Magnetic
Therapy and Nerve Regeneration; a research bibliography.
Pulsed
magnetic field therapy found effective at regenerating nerve tissue in studies
performed since the 1970's. Dispite being found to be effective and safe,
these techniques have never been applied to medical practice due to their simplicity
and effectiveness. Where pulse repetition rate (frequency measured
in Hertz) and magnetic flux density (amplitude measured in Gauss or Tesla) are
both within certain parameters, pulsed magnetic field research has proven that
PEMF's are capable of equal or better results than conventional therapies and
invasive procedures without side effects or risk of infection. Pulsed electromagnetic
field research has proven routinely that PEMF therapy is capable of inducing substantial
healing even where conventional medicine has failed.
Beside promoting various healing mechanisms, pulsed electromagnetic field therapy
has been found to have substantially beneficial neuroendocrine, neurological and
psychological effects; as well as having ability to promote bone, tissue and nerve
regeneration.
BBC NEWS: Tuesday, 11 May, 2004, 09:13 GMT 10:13 UK
Doctors at Imperial College London administered magnetic stimulation to the
brains of people with partial damage to their spinal cord. The therapy led to
improved muscle and limb movement, and increased ability to feel sensations.
Details of the technique - known as repetitive transcranial magnetic
stimulation (rTMS) - are published in the journal Spinal Cord. It works by using
an electromagnet placed on the scalp to generate brief magnetic pulses, about
the strength of an MRI scan. These pulses stimulate the part of the brain called
the cerebral cortex.
The technique was tested on four patients with what are known as
incomplete spinal cord injuries. This is where the spinal cord has not been entirely
severed, but the patient has still lost the ability to move or feel properly below
the injury point.
Researcher Dr Nick Davey said: "Through rTMS we may be able to help
people who have suffered partial injuries to the spinal cord recover some of their
movement and feeling. "We think it works by strengthening the information
leaving the brain through the undamaged neurons in the spinal cord. It may work
like physiotherapy but instead of repeating a physical task, the machine activates
the surviving nerves to strengthen their connections."
The patients had all sustained their injuries at least 18 months
previously and had already received conventional rehabilitation including physiotherapy.
They were all considered stable in that they were no longer undergoing natural
improvement. The patients received both real and sham rTMS treatment over
a three-week period. The rTMS treatment involved five consecutive days of magnetic
stimulation for one hour per day.
The researchers focused on a phenomenon called intracortical inhibition
which makes it easier for message from the brain to pass down the spinal cord
to the rest of the body. They found rTMS treatment resulted in a 37.5% drop
in intracortical inhibition, compared with normal physiotherapy.
This reduction in intracortical inhibition was accompanied by
improvement in both motor and sensory function, which lasted for at least three
weeks after the treatment. Dr Davey said: "Despite this, we still need
to be extremely careful in interpreting these results as we only sampled a small
number of patients.
"Further studies on larger groups of patients will need to be carried
out before we will know if this treatment is fully effective. "Similarly we have
no idea how long the treatment benefits will last over a longer period."
The treatment was originally designed to treat psychiatric disorders,
and has been used in treating some of the symptoms of schizophrenia.
Several hundred
pulsed electromagnetic field therapy citations contained in our
research bibliographies are linked directly to PubMed a service of the U.S. National Library of Medicine and the U.S. National Institutes of Health.
These studies are offered for your education only and are not intended as promotional
material for EarthPulse™ Technologies, LLC.
See
also; Sandyk R, Anninos
PA , Jacobson
JI; three pioneers of electromagnetic field therapy to treat Parkinson's, Alzheimer's and epilepsy.
PEMF
Background:
Research
Bibliographies:
EarthPulse
research:
Altern Ther Health Med. 2006 Sep-Oct;12(5):42-9.Links
Regenerative effects of pulsed magnetic field on injured peripheral nerves.
Mert T, Gunay I, Gocmen C, Kaya M, Polat S.
Department of Biophysics, University of Cukurova School of Medicine, Adana, Turkey.
Previous studies confirm that pulsed magnetic field (PMF) accelerates
functional recovery after a nerve crush lesion. The contention that PMF
enhances the regeneration is still controversial, however. The
influence of a new PMF application protocol (trained PMF) on nerve
regeneration was studied in a model of crush injury of the sciatic
nerve of rats. To determine if exposure to PMF influences regeneration,
we used electrophysiological recordings and ultrastructural
examinations. After the measurements of conduction velocity, the
sucrose-gap method was used to record compound action potentials (CAPs)
from sciatic nerves. PMF treatment during the 38 days following the
crush injury enhanced the regeneration. Although the axonal
ultrastructures were generally normal, slight to moderate myelin sheath
degeneration was noted at the lesion site. PMF application for 38 days
accelerated nerve conduction velocity, increased CAP amplitude and
decreased the time to peak of the CAP. Furthermore, corrective effects
of PMF on. the abnormal characteristics of sensory nerve fibers were
determined. Consequently, long-periodic trained-PMF may promote both
morphological and electrophysiological properties of the injured
nerves. In addition, corrective effects of PMF on sensory fibers may be
considered an important finding for neuropathic pain therapy.
Bioelectromagnetics. 2005 Jan;26(1):20-7. Links
Pulsed electromagnetic fields induce peripheral nerve regeneration and endplate enzymatic changes.
De Pedro JA, Pérez-Caballer AJ, Dominguez J, Collía F, Blanco J, Salvado M.
Department of Orthopaedics, University Hospital of Salamanca, Salamanca, Spain. jpedrom@usal.es
An experimental study was carried out in rats with the purpose of
demonstrating the capacity of pulsed electromagnetic fields (PEMFs) to
stimulate regeneration of the peripheral nervous system (PNS). Wistar
and Brown Norway (BN) rats were used. Direct sciatic nerve anastomoses
were performed after section or allograft interposition. Treatment
groups then received 4 weeks of PEMFs. Control groups received no
stimulation. The evaluation of the results was carried out by
quantitative morphometric analysis, demonstrating a statistically
significant increase in regeneration indices (P < 0.05) in the
stimulated groups (9000 +/- 5000 and 4000 +/- 6000) compared to the
non-stimulated groups (2000 +/- 4000 and 700 +/- 200). An increase of
NAD specific isocitrate dehydrogenase (IDH) activity was found along
with an increase in the activity of acetyl cholinesterase at the motor
plate. The present study might lead to the search for new alternatives
in the stimulation of axonal regenerative processes in the PNS and
other possible clinical applications. 2004 Wiley-Liss, Inc.
Spine. 2003 Dec 15;28(24):2660-6. Links
Exposure to pulsed magnetic fields enhances motor recovery in cats after spinal cord injury.
Crowe MJ, Sun ZP, Battocletti JH, Macias MY, Pintar FA, Maiman DJ.
Neuroscience Research Laboratories, The Clement J. Zablocki VA Medical Center, Milwaukee, WI 53295, USA. mcrowe@mcw.edu
STUDY DESIGN: Animal model study of eight healthy commercial cats was
conducted. OBJECTIVE: To determine whether pulsed electromagnetic field
(PMF) stimulation results in improvement of function after contusive
spinal cord injury in cats. SUMMARY OF BACKGROUND DATA: PMF stimulation
has been shown to enhance nerve growth, regeneration, and functional
recovery of peripheral nerves. Little research has been performed
examining the effects of PMF stimulation on the central nervous system
and no studies of PMF effects on in vivo spinal cord injury (SCI)
models have been reported. MATERIALS AND METHODS: PMF stimulation was
noninvasively applied for up to 12 weeks to the midthoracic spine of
cats with acute contusive spinal cord injury. The injury was produced
using a weight-drop apparatus. Motor functions were evaluated with the
modified Tarlov assessment scale. Morphologic analyses of the injury
sites and somatosensory-evoked potential measurements were conducted to
compare results between PMF-stimulated and control groups. RESULTS:
There was a significant difference in locomotor recovery between the
PMF-stimulated and control groups. Although not statistically
significant, PMF-stimulated spinal cords demonstrated greater sparing
of peripheral white matter and smaller lesion volumes compared to
controls. Somatosensory-evoked potential measurements indicated that
the PMF-stimulated group had better recovery of preinjury waveforms
than the control group; however, this observation also was not
statistically significant because of the small sample size.
CONCLUSIONS: This preliminary study indicates that pulsed magnetic
fields may have beneficial effects on motor function recovery and
lesion volume size after acute spinal cord injury.
J Reconstr Microsurg. 1999 Aug;15(6):427-31.Links
Using a direct current electrical field to promote spinal-cord regeneration.
Shen NJ, Wang SC.
Department of Orthopedics, People's Hospital of Hainan Province, Haikou, China.
The authors used a direct current electrical field to promote
spinal-cord regeneration in a canine model. Thirty-two dogs were
randomly divided into four groups. Complete spinal-cord injury was
induced, and electrical stimulators were then placed in the animals.
Group 1 served as controls; Groups 2 to 4 were experimental groups,
with varying stimulator voltages: 0V in Group 1, 12V in Groups 2 and 4,
and 6V in Group 3, with the stimulator implanted 6 hr after spinal-cord
injury in Group 4. Functional, electrophysiologic and morphometric
assessments were carried out 1 to 3 months postoperatively. Results
showed that spinal-cord function, cortical somatosensory evoked
potentials, number of neurons, sectional area of neurons, and Nissl
body density in the experimental groups were much better than those in
the control group. In addition, all the indices in Group 2 were better
than those in Groups 3 and 4. This indicated that direct current
electrical stimulation could effectively promote spinal-cord
regeneration and functional recovery in this model. The 12V voltage was
safe for the animals. The stimulator was not rejected by the host for a
relatively long period of time.
Plast Reconstr Surg. 1984 Feb;73(2):173-83.
Pulsing electromagnetic field therapy in nerve regeneration: an experimental
study in the cat. Orgel MG, O'Brien WJ, Murray HM.
A multidisciplinary approach to the study of peripheral nerve regeneration in
the cat has been presented. The purpose of this work has been to determine if
pulsing electromagnetic field (PEMF) therapy can enhance peripheral nerve
regeneration after injury. In equal groups of animals, two types of pulsing
electromagnetic field treatment were compared with untreated controls. All
animals underwent quantitative electrophysiologic and morphologic assessment at
the area of injury. In addition, muscle fiber sizing in the periphery and
retrograde labeling of anterior horn motoneurons with horseradish peroxidase
were studied. Results have shown no statistical differences between the groups
in electrophysiologic or morphologic parameters. However, in animals treated
with a pulse-burst electromagnetic field there was a statistically significant
improvement in the labeling and localization of anterior horn cells in the
central nervous system. These results indicate that pulse-burst electromagnetic
radiation can increase the numbers of motor neurons that reestablish appropriate
connections to the periphery after nerve injury. It remains to be seen if this
improved spinal cord organization can translate to improved peripheral
functional return.
PMID: 6695016 [PubMed - indexed for MEDLINE]
2: Clin Orthop. 1983 Dec;(181):283-90.
Effect of weak, pulsing electromagnetic fields on neural regeneration in the
rat.
Ito H, Bassett CA.
The short- and long-term effects of pulsed electromagnetic fields (PEMFs) on the
rate and quality of peripheral nerve regeneration were studied. High bilateral
transections of rat sciatic nerves were surgically approximated (a 1-mm gap was
left) and shielded with a Silastic sleeve. Animals were exposed to PEMFs for two
to 14 weeks after operation. Three groups of 20 rats each (control rats and rats
undergoing 12- and 24-hour/day PEMF exposure) were killed at two weeks.
Histologically, regenerating axons had penetrated the distal stump nearly twice
as far in the PEMF-exposed animals as in the control animals. Return of motor
function was judged two to 14 weeks after operation by the load cell-measured,
plantar-flexion force produced by neural stimulation proximal to the transection
site. Motor function returned earlier in experimental rats and to significantly
higher load levels than in control rats. Nerves from animals functioning 12-14
weeks after operation had less interaxonal collagen, more fiber-containing axis
cylinders, and larger fiber diameters in the PEMF-exposed group than in the
control rats. Histologic and functional data indicate that PEMFs improve the
rate and quality of peripheral nerve regeneration in the severed rat sciatic
nerve by a factor of approximately two.
PMID: 6641063 [PubMed - indexed for MEDLINE]
3: J Hand Surg [Br]. 1984 Jun;9(2):105-12.
An experimental study of the effects of pulsed electromagnetic field (Diapulse)
on nerve repair.
Raji AM.
This study investigates the effects of a pulsed electromagnetic field (PEMF)
(Diapulse) on experimentally divided and sutured common peroneal nerves in rats.
Evidence is presented to show that PEMF accelerates recovery of use of the
injured limb and enhances regeneration of damaged nerves.
PMID: 6747406 [PubMed - indexed for MEDLINE]
4: J Bone Joint Surg Br. 1983 Aug;65(4):478-92.
Effects of high-peak pulsed electromagnetic field on the degeneration and
regeneration of the common peroneal nerve in rats.
Raji AR, Bowden RE.
Apart from preliminary notices of present work, previous reports of experimental
and clinical trials of the effects of a high-peak pulsed electromagnetic field
(PEMF) on degeneration and regeneration of peripheral nerves lacked statistical
analysis. Therefore, we designed experiments with standardised operative,
histological, cytological and morphometric techniques to assess the effect of
PEMF on lesions of the common peroneal nerves in paired male rats matched for
age, environmental conditions and level and type of lesion. One of two types of
lesion was induced in the left common peroneal nerve: in 12 pairs of rats the
nerve was crushed just above the knee and in the remaining 12 pairs the nerve
was cut and immediately sutured at the same level. The right common peroneal
nerve of each rat served as a control. Animals received 15 minutes of PEMF
produced by a Diapulse machine or sham treatment daily for periods ranging from
three and a half days to eight weeks after injury. Healthy nerves were
unaffected, but after damage there were statistically significant differences
between PEMF treated and sham treated rats. PEMF accelerated the recovery of
injured limbs and the degeneration, regeneration and maturation of myelinated
axons; epineural, perineural and intraneural fibrosis was reduced; and the
luminal cross-sectional area of intraneural vessels increased after both types
of lesion. Findings are discussed and the need for clinical trials is stressed.
PMID: 6603461 [PubMed - indexed for MEDLINE]
5: Nippon Ika Daigaku Zasshi. 1986 Aug;53(4):321-31.
[Nerve regeneration with pulsing electromagnetic field stimulation, with special
reference to nerve conduction velocity]
[Article in Japanese]
Narita T.
PMID: 3760123 [PubMed - indexed for MEDLINE]
6: Paraplegia. 1976 May;14(1):12-20.
Experimental regeneration in peripheral nerves and the spinal cord in laboratory
animals exposed to a pulsed electromagnetic field.
Wilson DH, Jagadeesh P.
Peripheral nerve section and suture was performed in 132 rats. Postoperatively
half the animals were exposed to a pulsed electromagnetic field each day and
half were kept as controls. Nerve conduction studies, histology and nerve fibre
counts all indicated an increased rate of regeneration in the treated animals.
A
similar controlled study of spinal cord regeneration following hemicordotomy in
cats has been started, and preliminary results indicate that when the animals
are sacrificed three months after the hemicordotomy, the pulsed electromagnetic
therapy has induced nerve fibre regeneration across the region of the scar.
PMID: 180476 [PubMed - indexed for MEDLINE]
7: Plast Reconstr Surg. 1989 Feb;83(2):301-8.
Effect of a high-intensity static magnetic field on sciatic nerve regeneration
in the rat.
Cordeiro PG, Seckel BR, Miller CD, Gross PT, Wise RE.
Department of Plastic and Reconstructive Surgery, Lahey Clinic Medical Center,
Burlington, Mass.
The effect of a high-intensity static magnetic field on peripheral nerve
regeneration is evaluated in rat sciatic nerve. Forty-four rats underwent
sciatic nerve repair using polyethylene nerve guides. Postoperatively, the
animals were exposed to a 1-tesla magnetic field for 12 hours per day for 4
weeks with appropriate controls. Our results demonstrate that a 1-tesla static
magnetic field has no statistically significant effect on nerve regeneration as
determined by myelinated axon counts and electrophysiologic studies. Also, the
specific orientation of the sciatic nerve with respect to the magnetic field has
no influence on axonal growth or nerve conduction. Periods of restraint of 12
hours per day for 4 weeks significantly inhibit weight gain but have no effect
on peripheral nerve regeneration.
PMID: 2911629 [PubMed - indexed for MEDLINE]
8: Plast Reconstr Surg. 1991 Jan;87(1):122-9.
A multivariate approach to the treatment of peripheral nerve transection injury:
the role of electromagnetic field therapy.
Zienowicz RJ, Thomas BA, Kurtz WH, Orgel MG.
University of Massachusetts Medical School, Berkshire Medical Center,
Pittsfield.
A multivariate approach to the treatment of peripheral nerve transection injury
has been used in a rat model. A pilot study (48 animals, 8 groups) examined
variables associated with the method and timing of surgical repair, the arrest
of wallerian degeneration, and the role of pulsing electromagnetic field therapy
(PEMF) in functional recovery. A second phase (90 animals, 6 groups) then
studied the timing and duration of pulsing electromagnetic field therapy as the
only variable in larger groups of animals. The pilot study revealed that a
vein-graft conduit did not improve functional recovery compared with standard
epineurial repair. Additionally, delayed repair compared favorably with
immediate repair. The use of chlorpromazine to inhibit the toxic effects of
calcium influx appeared to enhance early functional recovery, and the
combination of delayed nerve repair and pulsing electromagnetic field therapy
seemed to consistently improve function. The second phase of the study has
demonstrated (for the first time) statistical improvement in ambulation in
animals treated with delayed surgical repair and prolonged pulsing
electromagnetic field therapy. We postulate that future treatment of nerve
transection injuries will involve a combined treatment regimen consisting of the
immediate arrest of wallerian degeneration, delayed surgery, and pulsing
electromagnetic field therapy.
PMID: 1984256 [PubMed - indexed for MEDLINE]
9: Lancet. 1982 Aug 21;2(8295):444-5.
Effects of high peak pulsed electromagnetic fields on degeneration and
regeneration of the common peroneal nerve in rate.
Raji AR, Bowden RE.
Publication Types:
Letter
PMID: 6124837 [PubMed - indexed for MEDLINE]
10: Equine Vet J. 1983 Oct;15(4):354-60.
Review of pulsing electromagnetic field therapy and its possible application to
horses.
Auer JA, Burch GE, Hall P.
The relevant literature on electrostimulation in general, and pulsing
electromagnetic fields in particular, is reviewed. DC current influences cell
behaviour by affecting transmembrane ion transport, which is often under
enzymatic control. Pulsing electromagnetic fields influence cell functions
through adsorption of ions or dipole formation at the cell membrane. Invasive
and non-invasive DC current stimulation is compared to pulsing electromagnetic
fields. The mode of application of pulsing electromagnetic fields to the equine
limb and suggested treatment times are briefly discussed. Two case reports are
used to illustrate the effect of pulsing electromagnetic fields in equine
fracture treatment.
Publication Types:
Case Reports
PMID: 6641683 [PubMed - indexed for MEDLINE]
11: Bioelectromagnetics. 1993;14(4):353-9.
Pretreatment of rats with pulsed electromagnetic fields enhances regeneration
of
the sciatic nerve.
Kanje M, Rusovan A, Sisken B, Lundborg G.
Department of Animal Physiology, University of Lund, Sweden.
Regeneration of the sciatic nerve was studied in rats pretreated in a pulsed
electromagnetic field (PEMF). The rats were exposed between a pair of Helmholtz
coils at a pulse repetition rate of 2 pps at a field density of 60 or 300
microT. The PEMF treatment was then discontinued. After an interval of recovery,
regeneration of the sciatic nerve was initiated by a crush lesion. Regeneration
of sensory fibers was measured by the "pinch test" after an additional 3-6 days.
A variety of PEMF pretreatments including 4 h/day for 1-4 days or exposure for
15 min/day during 2 days resulted in an increased regeneration distance,
measured 3 days after the crush lesion. This effect could be demonstrated even
after a 14-day recovery period. In contrast, pretreatment for 4 h/day for 2 days
at 60 microT did not affect the regeneration distance. The results showed that
PEMF pretreatment conditioned the rat sciatic nerve in a manner similar to that
which occurs after a crush lesion, which indicates that PEMF affects the
neuronal cell body. However, the mechanism of this effect remains obscure.
PMID: 8216387 [PubMed - indexed for MEDLINE]
12: Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi. 1999 Mar;13(2):114-8.
[Morphological changes and electrophysiological study of motor neuron of spinal
cord following delayed repair of peripheral nerve injury]
[Article in Chinese]
Zhu JY, Huang YT, Lu R.
Institute of Orthopaedics, Xijing Hospital, Fourth Military Medical University,
Xi'an Shanxi, P. R. China 710032.
OBJECTIVE: Following the delayed repair of peripheral nerve injury, the cell
number of anterior horn of the spinal cord and its ultrastructural changes,
motorneuron and its electrophysiological changes were investigated. METHODS: In
16 rabbits the common peroneal nerves of both sides being transected one year
later were divided into four groups randomly: the degeneration group and
regeneration of 1, 3 and 5 months groups. Another 4 rabbits were used for
control. All transected common peroneal nerves underwent epineural suture except
for the degeneration group the electrophysiological examination was carried out
at 1, 3 and 5 months postoperatively. Retrograde labelling of the anterior horn
cells was demonstrated and the cells were observed under light and
electronmicroscope. RESULTS: 1. The number of labelled anterior horn cell in the
spinal cord was 45% of the normal population after denervation for one year (P
<
0.01). The number of labelled cells increased steadily from 48% to 57% and 68%
of normal values at 1, 3 and 5 months following delayed nerve repair (P < 0.01).
2. The ultrastructure of the anterior horn cells of the recover gradually after
repair. 3. With the progress of regeneration the latency become shortened, the
conduction velocity was increased, the amplitude of action potential was
increased. CONCLUSION: Following delayed repair of injury of peripheral nerve,
the morphology of anterior horn cells of spinal cord and electrophysiological
display all revealed evidence of regeneration, thus the late repair of injury
of
peripheral nerve was valid.
PMID: 12080765 [PubMed - indexed for MEDLINE]
13: ASAIO Trans. 1988 Oct-Dec;34(4):947-51.
The use of DC electric fields to promote regeneration in the mammalian nervous
system.
Zanakis MF.
American Biointerface Corporation, New York, New York.
Publication Types:
Review
Review, Tutorial
PMID: 3064792 [PubMed - indexed for MEDLINE]
14: J UOEH. 1988 Mar 1;10(1):31-45.
The effect of long-term pulsing electromagnetic field stimulation on
experimental osteoporosis of rats.
Mishima S.
Department of Orthopedic Surgery, School of Medicine, University of Occupational
and Environmental Health, Kitakyushu, Japan.
The author performed experiments in order to investigate what biological effect
on the bone would be produced by long-term pulsing electromagnetic field (PEMF)
systemic stimulation. In some of the mature female rats used as experimental
animals, bilateral ovariectomy and right sciatic neurectomy were performed in
order to make a model osteoporosis. PEMF stimulation was produced by repetitive
pulse burst (RPB) waves at a positive amplitude of 25 mV, negative amplitude of
62.5 mV, burst width of 4.2 ms, pulse width of 230 microseconds and 12 Hz, with
the magnetic field strength within a cage being set at 3-10 Gauss. PEMF
stimulation over 6 months did not produce any effects on the physiologically
aged bones. PEMF stimulation also did not produce any effects on losed cortical
bone in osteoporotic hindlegs. On the other hand, an increase of bone volume and
bone formation activity was observed in the cancellous bone of osteoporotic
hindlegs. These findings suggested that PEMF stimulation exerted a preventive
effect against bone loss of osteoporotic hindlegs. Furthermore, an observed
increase in bone marrow blood flow seemed to be related with this increase of
bone volume and bone formation activity.
Publication Types:
Review
Review, Tutorial
PMID: 3285429 [PubMed - indexed for MEDLINE]
15: Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi. 1997 Jan;11(1):14-8.
[Influence of low energy He-Ne laser on regeneration of peripheral nerve]
[Article in Chinese]
Shi K, Lu R, Xu X.
Institute of Orthopedics of PLA, Fourth Military Medical University, Xi'an.
The purpose of this experiment was to elucidate the influence of the low-energy
He-Ne laser on the function of regeneration of peripheral nerve. Forty-four
rabbits about 2.5 kg body weight were used in the experiment. The animals were
divided into 4, 8, 12, 16 weeks groups according to the observation period. Six
animals were used in each irradiated group and in the control group 5 rabbits
were used in each observation period. Regeneration of the axon and myelinc
sheath, the latent rate of the common peroneal nerve, the conditions of the
anterior tibital muscle and the toe expansion test were all observed
systematically in both groups. The experimental results was: A few thin
regenerated axon was seen at 4 weeks in the irradiated group, while in the
control group it might be seen at 8 weeks, the P value was < 0.01. A low
amplitude latent rate of the common peroneal nerve is determined at the peroneal
side of the anterior tibial muscle in a few animal at 4 weeks of the irradiated
group, and it is not observed in the control group, from 12 to 16 weeks. THe
latent rate of the common peroneal nerve was the irradiated group than in the
controlled, the P value was < 0.01. The regeneration of the myeline sheath
was
evident in the irradiated group, and also the slstion of the musdle fibers
anterior tibial muscle was clearly visible than the controlled. 16 weeks
postoperatively, the toe expansion test was normal in the irradiated group,
while in the control group it was the same as seen at 12 weeks after operation
in the irradiated group. Now it was certain that the low-energy He-Ne laser
could promole the function of the spinal motor nerve cells and accelerate the
axonal regeneration.
PMID: 9867943 [PubMed - indexed for MEDLINE]
16: Clin Orthop. 1983 Dec;(181):277-82.
Effects of pulsing electromagnetic fields on bone growth and articular
cartilage.
Smith RL, Nagel DA.
Observations made during treatment of juvenile pseudarthrosis by pulsing
electromagnetic fields (PEMF) suggested that bone growth might be altered. PEMF
applied to immature rabbits under conditions of continuous stimulation (24
hours/day for 8 weeks) produced no major changes in bone growth. Continuous
stimulation by PEMF induced a statistically significant increase (22%) in
femoral articular cartilage glycosaminoglycan. Intermittent PEMF stimulation (12
hours with stimulation/12 hours without stimulation) for 18 weeks produced no
significant change in bone growth or time of epiphyseal plate closure. No
significant changes in the physical characteristics of growing bone were
observed with any treatment.
PMID: 6641061 [PubMed - indexed for MEDLINE]
17: J Reconstr Microsurg. 1999 Aug;15(6):427-31.
Using a direct current electrical field to promote spinal-cord regeneration.
Shen NJ, Wang SC.
Department of Orthopedics, People's Hospital of Hainan Province, Haikou, China.
The authors used a direct current electrical field to promote spinal-cord
regeneration in a canine model. Thirty-two dogs were randomly divided into four
groups. Complete spinal-cord injury was induced, and electrical stimulators were
then placed in the animals. Group 1 served as controls; Groups 2 to 4 were
experimental groups, with varying stimulator voltages: 0V in Group 1, 12V in
Groups 2 and 4, and 6V in Group 3, with the stimulator implanted 6 hr after
spinal-cord injury in Group 4. Functional, electrophysiologic and morphometric
assessments were carried out 1 to 3 months postoperatively. Results showed that
spinal-cord function, cortical somatosensory evoked potentials, number of
neurons, sectional area of neurons, and Nissl body density in the experimental
groups were much better than those in the control group. In addition, all the
indices in Group 2 were better than those in Groups 3 and 4. This indicated that
direct current electrical stimulation could effectively promote spinal-cord
regeneration and functional recovery in this model. The 12V voltage was safe for
the animals. The stimulator was not rejected by the host for a relatively long
period of time.
PMID: 10480562 [PubMed - indexed for MEDLINE]
18: Brain Res. 1985 Nov 25;348(1):159-62.
Regeneration of gamma-fusimotor axons after nerve-freeze injury in the cat.
Scott JJ.
Nerve injury was produced by application of dry ice to the common peroneal
nerve. After 20 weeks, muscle-spindle primary endings responded normally to
stretch and the spindles were found to have a fully functional fusimotor
innervation.
PMID: 4063820 [PubMed - indexed for MEDLINE]
19: Muscle Nerve. 2001 May;24(5):662-6.
Partial peripheral motor nerve lesions induce changes in the conduction
properties of remaining intact motoneurons.
Havton LA, Hotson JR, Kellerth JO.
Department of Neurology, University of California, Los Angeles, and Reed
Neurological Research Center, 710 Westwood Plaza, Los Angeles, California
90095-1769, USA. LHavton@mednet.ucla.edu
A partial injury or loss of peripheral motor axons is followed by compensatory
sprouting of remaining intact motor axons in order to reinnervate muscle. Little
is known, however, about the electrophysiologic properties proximally of these
intact motoneurons and their axons following injury of neighboring motor axons.
We studied the conduction properties of intact cat motor axons and motoneurons
proximal to the site of a partial peripheral nerve section. Twelve weeks after
the partial transection of the cat medial gastrocnemius motor nerve, there was
a
significant (7%) reduction in conduction velocity and a 13% prolongation in
afterhyperpolarization half-decay time in the remaining intact motoneurons,
compared with controls. Partial injury to motor nerves thus induces reactive
electrophysiologic changes in the remaining intact motoneurons and their axons,
perhaps associated with compensatory sprouting within partially denervated
muscle. Copyright 2001 John Wiley & Sons, Inc.
PMID: 11317276 [PubMed - indexed for MEDLINE]
20: J Hand Surg [Am]. 1983 May;8(3):248-53.
Specificity of muscle reinnervation after epineurial and individual fascicular
suture of the rat sciatic nerve.
Brushart TM, Tarlov EC, Mesulam MM.
We experimentally analyzed the specificity of muscle reinnervation after suture
and regeneration of rat sciatic nerve. We used a horseradish peroxidase (HRP)
technique of axon tracing to compare the number and location of motoneurons that
innervate muscle via the peroneal nerve after epineurial and individual
fascicular suture of the parent sciatic nerve. These motoneurons are
significantly reduced in number from control levels and are often in spinal cord
locations that indicate previous innervation of antagonistic muscle via the
tibial nerve. This inappropriate reinnervation of peroneal muscle by tibial
motoneurons is minimized by individual fascicular suture without compromise of
overall reinnervation. Our findings thus support the hypothesis that individual
fascicular suture may avoid distortion of the central connections of peripheral
units.
PMID: 6348148 [PubMed - indexed for MEDLINE]
21: Science. 1980 May 9;208(4444):603-5.
Alteration in connections between muscle and anterior horn motoneurons after
peripheral nerve repair.
Brushart TM, Mesulam MM.
The connections between the spinal cord and lower leg muscles of the rat are
significantly altered by repair of the intervening sciatric nerve. Muscles
supplied by the peroneal branch of the sciatic are innervated by fewer
motoneurons after sciatic repair. Many of these neurons originally innervated
the peroneal muscles, and others formerly served the antagonistic tibial
muscles. Perikarya in the size range of alpha motoneurons regained peripheral
connections with greater frequency than those in the gamma range. There are thus
postoperative defects in the extent and specificity of alpha reinnervation as
well as in the degree of gamma control.
PMID: 7367884 [PubMed - indexed for MEDLINE]
22: Spine. 1984 Apr;9(3):273-9.
The effect of postoperative electromagnetic pulsing on canine posterior spinal
fusions.
Kahanovitz N, Arnoczky SP, Hulse D, Shires PK.
An experimental canine study was devised to evaluate the efficacy of a
noninvasive adjunct to improve the rate and quality of the posterior fusion mass
over the standard surgical technique. Ten large adult mongrel dogs underwent a
three-level lumbar spinal fusion. Bone excised from the spinous processes was
packed in removed facet joints and over the decorticated laminae. To insure
rigid internal fixation, custom-made distraction instrumentation was placed
bilaterally under the laminae of the vertebrae above and below the three fused
vertebrae. Five dogs underwent electromagnetic pulsing, and five dogs acted as
controls. Two dogs were sacrificed at 4, 6, 9, 12, and 15 weeks to assess the
radiographic and histologic status of the fusion mass. Preoperative and
preautopsy hematologic studies as well as gross and histologic autopsy specimens
revealed no abnormalities attributable to the electromagnetic pulsing.
High-resolution radiography and histologic studies showed earlier incorporation
of the graft, improved new bone formation, and better organization of the fusion
mass in the 4-, 6-, and 9-week stimulated specimens. However, by 12 and 15 weeks
there did not appear to be any histologic or radiographic differences between
the stimulated and control dogs. Although electromagnetic pulsing appears to
produce an early accelerated osteogenic response, it does not appear to improve
the overall results of primary canine spinal fusions.
PMID: 6729593 [PubMed - indexed for MEDLINE]
23: Exp Neurol. 1983 May;80(2):418-26.
Reinnervation of the gastrocnemius muscle by the contralateral S1 nerve root.
Shonnard N, Wakefield C.
Functional regeneration after transposition of a ventral nerve root was
established in the adult cat. Reconstruction of the ventral root, using
microsurgical methods, directed the right S1 ventral nerve root to innervate the
left gastrocnemius muscle. Stimulus-induced unit responses were recorded from
the left gastrocnemius muscle 5 to 8 months after the root cross, demonstrating
the reestablishment of neuromuscular connections. The innervation of the left
gastrocnemius muscle by neurons in the right ventral horn of the spinal cord was
verified by injecting horseradish peroxidase into the muscle. Horseradish
peroxidase reaction product was located in alpha and gamma motor neurons in the
right S1 segment of the spinal cord. Computer-assisted determination of the soma
area of the labeled neurons was compared with a normal S1 innervation of the
gastrocnemius muscle. Analysis of the percentage of cells of a given soma area
demonstrated an overall decrease in soma area in the operated animals. Because
ventral root reconstruction can result in innervation of a foreign muscle,
studies such as this may encourage repair or reconstruction of nerve roots to
gain some functional recovery after spinal cord or nerve root injuries.
PMID: 6840247 [PubMed - indexed for MEDLINE]
24: Bioelectromagnetics. 1996;17(1):44-7.
Effect of low-intensity millimeter wave electromagnetic radiation on
regeneration of the sciatic nerve in rats.
Kolosova LI, Akoev GN, Avelev VD, Riabchikova OV, Babu KS.
Pavlov Institute of Physiology, Russian Academy of Sciences, St. Petersburg.
The effect of low-intensity millimeter wave electromagnetic radiation (MWR) on
regeneration of the rat sciatic nerve after transection and microsurgical
reapproximation was examined. Rats were exposed to 54 GHz MWR at a power density
of 4 mW/cm2. It was found that MWR treatment of the femoral skin in the area of
suture accelerated the regeneration of nerve fibers. At the twentieth
postoperative day, the MWR-treated animals had a 32% increase in the
regeneration distance compared to the control animals. The conduction velocity
showed a 26% increase in the MWR-treated animals.
PMID: 8742755 [PubMed - indexed for MEDLINE]
25: J Neurosci Res. 1995 Dec;42(5):692-9.
Acute treatment with pulsed electromagnetic fields and its effect on fast axonal
transport in normal and regenerating nerve.
Sisken BF, Jacob JM, Walker JL.
Department of Anatomy and Neurobiology, University of Kentucky, Lexington 40506,
USA.
The mechanism whereby low-frequency electromagnetic fields accelerate axonal
regrowth and regeneration of peripheral nerve after crush lesion is not known.
One candidate is an alteration in axonal transport. In this study we exposed
unoperated rats for 15 min/day, and rats that had undergone a crush lesion of
the sciatic nerve, for 1 hr/day for 2 days, to 2-Hz pulsed electromagnetic
fields. To label fast transported proteins, [3H]-proline was microinjected into
the spinal cord, and the sciatic nerves were removed 2, 3.5, and 5 hr later. The
rates of fast axonal transport were obtained for animals in all groups by
counting sequential 2-mm segments of nerves. The following transport rates were
found: in unoperated normal sciatic nerve not exposed to PEMF, 373 +/- 14
mm/day; in unoperated normal nerve exposed to PEMF, 383 +/- 14 mm/day; in sham
crush nerves not exposed to PEMF, 379 +/- 19 mm/day; in sham crush nerve exposed
to PEMF, 385 +/- 17 mm/day; in crushed nerves not exposed to PEMF, 393 +/- 16
mm/day. and in crushed nerves exposed to PEMF, 392 +/- 15 mm/day. The results
of
these experiments indicate that 1) a crush injury to the sciatic nerve does not
alter the rate of fast axonal transport, and 2) low-frequency pulsed
electromagnetic fields do not alter fast axonal transport rates in operated
(crush) or unoperated sciatic nerves.
PMID: 8600302 [PubMed - indexed for MEDLINE]
26: Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi. 1997 Jan;11(1):10-3.
[Influence of low energy He-Ne laser on spinal motor nerve cell]
[Article in Chinese]
Shi K, Lu R, Xu X.
Institute of Orthopedics of PLA, Fourth Military Medical University, Xi'an.
The object of this experimental study was to investigate the influence of
low-energy He-Ne laser on the motor nerve cells of the spinal cord. The
experimental study included as follws: (1) Four rabbits were used in this
experiment. The L5-6 spinal cord segment was irradiated by He-Ne laser
percutaneously, the nerve velocity of the comon peroneal nerve was measured in
order to determine the function of the spinal motor nerve cells when the
peripheral nerve was intact. (2) The common peroneal nerve was transected on one
side wothout repair, two weeks after laser irradiation, the grey mater of the
spinal cord of L5-6 segment was procured for electronic microscopic examination.
(3) The common peroneal nerve on the contralateral side was transected and
followed by end-to-end anastomosis, and laser irradiation was done on the same
spinal cord segment. Two weeks after irradiation, the nerve velocity of the
common peroneal nerve and the toe expanding test were investigated. The results
were: (1) the He-Ne laser can influence the spinal motor nerve cells function
as
expressed by latent rate when the peripherial nerve is intact. i.e. the nerve
velocity is slower than mormal, and the amplitude is markedly decreared. (2) the
change of the microstructure of the spinal motor nerve cells is comparatively
slight in the 10 and 15 minutes groups. (3) the recovery of the nerve velocity
and the toe expansion are more earlier in the 15 min. group. In short, the
low-energy He-Ne laser can influence the function of the spinal motor nerve
cells.
PMID: 9867942 [PubMed - indexed for MEDLINE]
27: J Bone Joint Surg Am. 1982 Jul;64(6):888-95.
Modification of fracture repair with selected pulsing electromagnetic fields.
Bassett CA, Valdes MG, Hernandez E.
We assayed different pulsing electromagnetic fields for their effects on the
mechanical and histological repair properties of an osteotomy of the radius of
the rat fourteen days postoperatively. Highly significant differences were found
in the control and experimental initial load values and their decay as a
function of time. These results correlate well with the histological pattern in
the bridging callus. A pulse that produces an increase (above the control level)
in initial load by a factor of 2.4 and a slower decay was characterized by more
extensive calcification of fibrocartilage and its replacement by fibrous bone
at
this early, but important, stage in fracture-healing.
PMID: 7085716 [PubMed - indexed for MEDLINE]
28: J Neurosurg. 1995 Apr;82(4):623-9.
The fate of motoneurons in the spinal cord after peripheral nerve repair: a
quantitative study using the neural tracer horseradish peroxidase.
Gilmour JA, Myles LM, Glasby MA.
Department of Anatomy, University of Edinburgh, Medical School, Scotland.
This study assessed the changes that occurred in the spinal motoneuron pool
after the repair of a specific peripheral nerve by means of several clinically
appropriate surgical techniques: nerve graft, muscle graft, and epineurial
suture. The motoneuron pool relating to a single muscle was assessed at 50, 100,
200, and 300 days after repair via retrograde axonal transport of the neural
tracer horseradish peroxidase. The results indicate that although a small
portion of the motoneuron population dies following peripheral nerve surgery,
this is not a significant number. The majority of the anterior horn cells appear
to have the ability to both survive nerve transection and form new functional
connections with the regenerated nerve after repair. The degree of cell loss is
influenced by the nature of the injury and the method of repair implemented.
Injuries involving neurotmesis result in the loss of a greater proportion of the
cell population than less severe injuries involving axonotmesis. A greater
proportion of the motoneuron population is preserved when the severed nerve has
been repaired using a direct epineurial suture than when repair is achieved by
means of a graft. The two methods of grafting produced comparable results,
although the muscle graft tended to result in the preservation of a greater
number of cells than the nerve graft, making it an acceptable alternative method
for the surgical repair of short gaps in peripheral nerves.
PMID: 7897525 [PubMed - indexed for MEDLINE]
29: Exp Mol Med. 2002 Mar 31;34(1):53-9.
Enhanced expression of neuronal nitric oxide synthase and phospholipase C-gamma1
in regenerating murine neuronal cells by pulsed electromagnetic field.
Kim SS, Shin HJ, Eom DW, Huh JR, Woo Y, Kim H, Ryu SH, Suh PG, Kim MJ, Kim JY,
Koo TW, Cho YH, Chung SM.
Department of Pathology, Ulsan University College of Medicine, Korea.
Pulsed electromagnetic field (PEMF) has been shown to improve the rate of
peripheral nerve regeneration. In the present study we investigated the
expression of neuronal nitric oxide synthase (nNOS) and phospholipase C-gamma1
(PLC-gamma1) in regenerating rat laryngeal nerves during the exposure to PEMF
after surgical transection and reanastomosis. Axons were found to regenerate
into the distal stump nearly twice faster in PEMF-exposed animals than in the
control. Consistently, motor function was better recovered in PEMF-treated rats.
The expression of nNOS and PLC-gamma1 was highly enhanced in the regenerated
nerves.
PMID: 11989979 [PubMed - indexed for MEDLINE]
30: Spine. 2003 Dec 15;28(24):2660-6.
Exposure to pulsed magnetic fields enhances motor recovery in cats after spinal
cord injury.
Crowe MJ, Sun ZP, Battocletti JH, Macias MY, Pintar FA, Maiman DJ.
Neuroscience Research Laboratories, The Clement J. Zablocki VA Medical Center,
Milwaukee, WI 53295, USA. mcrowe@mcw.edu
STUDY DESIGN: Animal model study of eight healthy commercial cats was conducted.
OBJECTIVE: To determine whether pulsed electromagnetic field (PMF) stimulation
results in improvement of function after contusive spinal cord injury in cats.
SUMMARY OF BACKGROUND DATA: PMF stimulation has been shown to enhance nerve
growth, regeneration, and functional recovery of peripheral nerves. Little
research has been performed examining the effects of PMF stimulation on the
central nervous system and no studies of PMF effects on in vivo spinal cord
injury (SCI) models have been reported. MATERIALS AND METHODS: PMF stimulation
was noninvasively applied for up to 12 weeks to the midthoracic spine of cats
with acute contusive spinal cord injury. The injury was produced using a
weight-drop apparatus. Motor functions were evaluated with the modified Tarlov
assessment scale. Morphologic analyses of the injury sites and
somatosensory-evoked potential measurements were conducted to compare results
between PMF-stimulated and control groups. RESULTS: There was a significant
difference in locomotor recovery between the PMF-stimulated and control groups.
Although not statistically significant, PMF-stimulated spinal cords demonstrated
greater sparing of peripheral white matter and smaller lesion volumes compared
to controls. Somatosensory-evoked potential measurements indicated that the
PMF-stimulated group had better recovery of preinjury waveforms than the control
group; however, this observation also was not statistically significant because
of the small sample size. CONCLUSIONS: This preliminary study indicates that
pulsed magnetic fields may have beneficial effects on motor function recovery
and lesion volume size after acute spinal cord injury.
PMID: 14673366 [PubMed - in process]
31: Exp Neurol. 1994 Feb;125(2):302-5.
Enhancement of functional recovery following a crush lesion to the rat sciatic
nerve by exposure to pulsed electromagnetic fields.
Walker JL, Evans JM, Resig P, Guarnieri S, Meade P, Sisken BS.
Division of Orthopaedic Surgery, University of Kentucky College of Medicine,
Shriners Hospitals for Crippled Children, Lexington.
Previous studies showed that exposure to pulsed electromagnetic fields (PEMF)
produced a 22% increase in the axonal regeneration rate during the first 6 days
after crush injury in the rat sciatic nerve. We used the same injury model to
assess the effect on functional recovery. The animals were treated with whole
body exposure to PEMF (0.3 mT, repetition rate 2 Hz) for 4 h/day during Days 1-5
while held in plastic restrainers. Functional recovery was serially assessed up
to Postinjury Day 43 using recently described video imaging of the 1-5 toe
spread and the gait-stance duration. Footprint analysis was also used with
calculation of a sciatic function index. Those animals treated with PEMF had
improved functional recovery, as compared to sham controls, using the tests for
video 1-5 toe spread and gait-stance duration (P = 0.001 and P = 0.081,
respectively). This effect was found throughout the 43-day recovery period. No
effect was found using the sciatic function index. This study confirms that
functional recovery after nerve crush lesion is accelerated by PEMF and has
broad implications for the clinical use of these fields in the management of
nerve injuries.
PMID: 8313945 [PubMed - indexed for MEDLINE]
32: J Neurosurg. 1996 Feb;84(2):234-43.
Reinnervation of avulsed and reimplanted ventral rootlets in the cervical spinal
cord of the cat.
Hoffmann CF, Marani E, van Dijk JG, vd Kamp W, Thomeer RT.
Department of Neurosurgery, University of Leiden, The Netherlands.
Spinal nerve root avulsions frequently occur in brachial plexus injuries caused
by traction. Such lesions are considered to afflict the central nervous system
(CNS) and are, therefore, believed to be beyond surgical repair. The present
experimental study was initiated to challenge this hypothesis. The ventral
rootlets of C-7 were avulsed from the spinal cord in 28 cats via an anterior
approach and subsequently reimplanted into the cord at the site of origin. In
nonoperated control cats and cats undergoing reimplantation,
electrophysiological experiments were performed and horseradish peroxidase was
administered to the spinal nerve on the reimplanted side after survival times
ranging from 6 to 293 days. Spinal cord sections in all cats were stained for
neurofilament, acetylcholinesterase (AChE), Nissl, and glial fibrillary acidic
protein. Horseradish peroxidase-labeled ventral horn motoneurons were found as
early as 14 days after reimplantation and their number increased with time. On
Days 209 and 293, the number of labeled neurons equaled the number of labeled
ventral horn neurons in the two control cats that did not undergo surgery.
Starting on Day 6 after reimplantation, the appearance of the ventral horn and
the white matter in the neurofilament, AChE, and Nissl-stained sections changed
as a result of the CNS response to the injury. A return to their normal
appearance could be observed in these stainings from Day 209 onward. Glial
fibrillary acidic protein-positive astrocytic tissue was consistently found in
the ventral horn and in the white matter reimplantation area. From Day 69
onward, electrophysiological stimulation of the spinal nerve C-7 on the
reimplanted side elicited an electromyogram response in the spinodeltoid muscle.
The latency and threshold intensity of the C-7 responses were initially
increased but equalized to match the nonoperated controls between 98 and 122
days after reimplantation. The results of this study show that functional
regeneration of ventral horn neurons after root avulsion and subsequent
reimplantation in the cat is possible.
PMID: 8592226 [PubMed - indexed for MEDLINE]
33: Lancet. 1984 Mar 31;1(8379):695-8.
Pulsed electromagnetic field therapy of persistent rotator cuff tendinitis. A
double-blind controlled assessment.
Binder A, Parr G, Hazleman B, Fitton-Jackson S.
The value of pulsed electromagnetic fields (PEMF) for the treatment of
persistent rotator cuff tendinitis was tested in a double-blind controlled study
in 29 patients whose symptoms were refractory to steroid injection and other
conventional conservative measures. The treated group (15 patients) had a
significant benefit compared with the control group (14 patients) during the
first 4 weeks of the study, when the control group received a placebo. In the
second 4 weeks, when all patients were on active coils, no significant
differences were noted between the groups. This lack of difference persisted
over the third phase, when neither group received any treatment for 8 weeks. At
the end of the study 19 (65%) of the 29 patients were symptomless and 5 others
much improved. PEMF therapy may thus be useful in the treatment of severe and
persistent rotator cuff and possibly other chronic tendon lesions.
Publication Types:
Clinical Trial
Randomized Controlled Trial
PMID: 6143039 [PubMed - indexed for MEDLINE]
34: J Bone Joint Surg Am. 1982 Oct;64(8):1214-20.
Treatment of therapeutically resistant non-unions with bone grafts and pulsing
electromagnetic fields.
Bassett CA, Mitchell SN, Schink MM.
This study reviews the cases of eighty-three adults with ununited fractures who
were treated concomitantly with bone-grafting and pulsed electromagnetic fields.
An average of 1.5 years had elapsed since fracture and the use of this combined
approach. Nearly one-third of the patients had a history of infection, and an
average of 2.4 prior operations had failed to produce bone union. Thirty-eight
patients who were initially treated with grafts and pulsed electromagnetic
fields for ununited fractures with wide gaps, synovial pseudarthrosis, and
malalignment achieved a rate of successful healing of 87 per cent. Forty-five
patients who had initially been treated unsuccessfully with pulsing
electromagnetic fields alone had bone-grafting and were re-treated with pulsing
electromagnetic fields. Ninety-three per cent of these fractures healed. The
residual failure rate after two therapeutic attempts, one of which was
operative, was 1.5 per cent. The median time to union for both groups of
patients was four months.
PMID: 6752151 [PubMed - indexed for MEDLINE]
35: Prog Clin Biol Res. 1986;210:251-60.
Effects of applied DC fields on sensory nerve sprouting and motor-nerve
regeneration in adult rats.
Pomeranz B.
PMID: 3960914 [PubMed - indexed for MEDLINE]
36: JAMA. 1982 Aug 27;248(8):921.
Pulsing electromagnetic field treatment.
Irvine RD.
Publication Types:
Letter
PMID: 7097952 [PubMed - indexed for MEDLINE]
37: Clin Exp Rheumatol. 1985 Oct-Dec;3(4):333-6.
Chronic lateral humeral epicondylitis--a double-blind controlled assessment of
pulsed electromagnetic field therapy.
Devereaux MD, Hazleman BL, Thomas PP.
Pulsed electromagnetic fields (PEMF) have been shown to be beneficial in the
treatment of rotator cuff tendinitis. As lateral humeral epicondylitis (tennis
elbow) is a similar chronic tendon lesion, 30 patients with both clinical and
thermographic evidence of tennis elbow were randomly allocated to receive either
active or inactive PEMF therapy. Treatment was continued for a minimum period
of
eight weeks. At this time there was no statistical difference between the two
groups.
Publication Types:
Clinical Trial
Randomized Controlled Trial
PMID: 4085165 [PubMed - indexed for MEDLINE]
38: Electromyogr Clin Neurophysiol. 1994 Jul-Aug;34(5):259-64.
Electrophysiological study of regenerated rabbit tibial and peroneal nerves:
autologous versus non-neural grafts.
Wessel K, Muller H, Deseniss V, Dombert T.
Department of Neurology, Medical University of Lubeck, Germany.
In recent years, successful experimental nerve regeneration using extracellular
matrix as implants has been reported. In the present study, we compared
peripheral nerve regeneration through implants of amnion membrane matrix (AMM)
and umbilical cord membrane matrix (UCMM) versus autologous nerve
transplantation, bridging gaps 8-12 mm in length in rabbit tibial and peroneal
nerves. The data are based on direct nerve stimulation and recording of
somatosensory evoked potentials (SEPs) and muscle action potentials (MAPs) to
measure functional recovery after these different types of neuroplastic
bridging. Incomplete regeneration was demonstrable as missing SEPs (15-22%),
missing MAPs (17-42%), a mean delay of SEPs and distal motor latencies of
approximately 40-50% compared with a normal control group, and slowed motor
conduction velocities by approximately 50%. There were no significant
differences between the three different types of neuroplastic bridging. Most of
the AMM and UCMM implants (80-100%), but none of the autologous nerve
transplants, caused inadequate connections with peripheral targets. We conclude
that extracellular matrix implantation represents a useful experimental model
for studying the biological basis of nerve regeneration, but does not yet serve
as a tool for therapeutic applications.
PMID: 7956874 [PubMed - indexed for MEDLINE]
39: J Neurosurg. 2001 Jan;94(1 Suppl):82-90.
Innervation of the caudal denervated ventral roots and their target muscles by
the rostral spinal motoneurons after implanting a nerve autograft in spinal
cord-injured adult marmosets.
Liu S, Aghakhani N, Boisset N, Said G, Tadie M.
Laboratory of Experimental Neurosurgery, Faculte de M ecine Paris-Sud,
University of Paris XI, France.
OBJECT: The authors conducted a study to determine the effects of using a nerve
autograft (NAG) to promote and guide axonal regrowth from the rostral spinal
cord to the caudal lumbar ventral nerve roots to restore hindlimb motor function
in adult marmosets after lower thoracic cord injury. METHODS: Nine animals
underwent a left-sided hemisection of the spinal cord at T-12 via left-sided
T9-L3 hemilaminectomy, with section of all ipsilateral lumbrosacral ventral
nerve roots. In the experimental group (five animals), an NAG obtained from the
right peroneal nerve was anastomosed with the sectioned and
electrophysiologically selected lumbar ventral roots (left L-3 and L-4)
controlling the left quadriceps muscle and then implanted into the left
ventrolateral T-10 cord. In the control group (four animals), the
sectioned/selected lumbar ventral roots were only ligated. After surgery, all
marmosets immediately suffered from complete paralysis of their left hindlimb.
Five months later, some clinical signs of reinnervation such as tension and
resistance began to appear in the paralyzed quadriceps of all experimental
animals that received autografts. Nine months postoperatively, three of the five
experimental marmosets could maintain their lesioned hindlimb in hip flexion.
Muscle action potentials and motor evoked potentials were recorded from the
target quadriceps in all experimental marmosets, but these potentials were
absent in the control animals. Horseradish peroxidase retrograde labeling from
the distal sectioned/reconnected lumbar ventral roots traced 234+/-178 labeled
neurons in the ipsilateral T8-10 ventral horn, mainly close to the NAG tip.
Histological analysis showed numerous regenerating axons in this
denervated/reconnected nerve root pathway, as well as newly formed motor
endplates in the denervated/reinnervated quadriceps. No axonal regeneration was
detected in the control animals. CONCLUSIONS: These data indicate that the
rostral spinal neurons can regrow into the caudal ventral roots through an NAG,
thereby innervating the target muscle in adult marmosets after spinal cord
injury.
PMID: 11147873 [PubMed - indexed for MEDLINE]
40: Exp Neurol. 1998 Jul;152(1):95-100.
Motoneuron survival after neonatal peroneal nerve injury in the rat-evidence for
the sparing effect of reciprocal inhibition.
Waters HJ, Barnett G, O'Hanlon GM, Lowrie MB.
Division of Biomedical Sciences, Imperial College School of Medicine, Norfolk
Place, London, W2 1PG, United Kingdom.
Sciatic nerve crush at birth results in the death of most of the motoneurons in
the sciatic motor pool. It has been proposed that these cells die through
excessive activation which can be explained partly by an increased
susceptibility to NMDA. However, it is also possible that decreased inhibitory
mechanisms resulting from nerve injury may contribute to overactivation of the
motoneurons. In this study we compared the survival of motoneurons innervating
two muscles in the peroneal motor pool, tibialis anterior and extensor digitorum
longus, after either sciatic or common peroneal nerve crush. These two
procedures both axotomize the motoneurons but differ in their effects on
afferent input. Sciatic nerve crush severely reduces the afferent input from the
antagonist muscles innervated via the tibial nerve, whereas common peroneal
nerve crush preserves them. Using retrograde labeling with horseradish
peroxidase, we found that almost twice as many motoneurons survived common
peroneal nerve crush than sciatic nerve crush and that muscle weight showed a
corresponding significant improvement. A control experiment excluded the
possible involvement of increased stretch of the muscles as a result of common
peroneal nerve crush alone as an explanation for the improvement. We therefore
suggest that the increased survival of motoneurons after peroneal nerve crush
was due to the preservation of their reciprocal inhibitory input. However, since
even with this improvement the majority of motoneurons still died, loss of
reciprocal inhibition probably does not play a major role in the death of
motoneurons induced by overactivation. Copyright 1998 Academic Press.
PMID: 9682016 [PubMed - indexed for MEDLINE]
41: Zh Nevropatol Psikhiatr Im S S Korsakova. 1989;89(5):41-4.
[Characteristics of the effect of a constant electromagnetic field on reparative
processes in spinal cord injuries]
[Article in Russian]
Tkach EV, Abilova AN, Gazalieva ShM.
In 171 white rats the spinal cord was completely sectioned in the upper thoracic
region. In 46 control rats an early crude spinal cord scar was identified which
precluded the growth of nervous fibers. On the contrary, in animals exposed to
constant magnetic field a smooth spinal cord scar was found with collaterals of
anterior spinal arteria, recrease of the destruction zone and nervous fiber
growth across the scar, This resulted in restored hind paw motility by 56 +/-
4.8% as related to control rats in which motility did not restore. Magnet
therapy applied as a part in combined restitutional therapy in 104 patients in
early restitution period yielded a 46.15 +/- 4.89% to 76.32 +/- 4.87% increase
in the rate of restoration of motor and sensory functions. With the therapy
applied in late periods, the restitution was 48.1 +/- 5.6% and 78.1 +/- 3.9%,
respectively. The magnetic field is considered as a reparation booster in spinal
cord trauma applicable in any stage of the disease.
PMID: 2781918 [PubMed - indexed for MEDLINE]
42: Am J Otolaryngol. 1993 Jan-Feb;14(1):43-8.
Misdirected regeneration of injured recurrent laryngeal nerve in the cat.
Nahm I, Shin T, Watanabe H, Maeyama T.
Department of Otolaryngology, Saga Medical School, Japan.
INTRODUCTION: Misdirected regeneration (MR) frequently occurs following injury
to the recurrent laryngeal nerve (RLN) resulting in neurotmesis or axonotmesis.
Physiological and anatomic parameters involved in the functional recovery of the
larynx following freezing injury or neurorrhaphy of the RLN were studied. A
multi-facilitated approach is undertaken to clarify the functional abnormalities
caused by the MR after recurrent laryngeal nerve injury. MATERIALS AND METHODS:
Three groups of adult cats were studied. These included controls, cats with
recurrent laryngeal neurorrhaphy, and cats with recurrent laryngeal nerve freeze
injuries. From 2 weeks to 9 months after the nerve injury, the animals were
studied endoscopically and with electromyography (EMG). Using the same animal,
the number and location of motoneurons supplying the ipsilateral posterior
cricoarytenoid (PCA) muscle were examined with horseradish peroxidase (HRP).
Animals were subsequently sacrificed to study the pattern of reinnervation.
RESULTS: Following neurorrhaphy all cats had vocal cord paralysis. After
neurorrhaphy, effective motion function did not return in the affected vocal
cord and it remained fixed in the paramedian position. Although EMG of the
laryngeal muscles of the affected side showed interference voltage, the pattern
of activities was markedly different from that of the unaffected side, and
reciprocity among the laryngeal muscles was not restored. The number of PCA
motoneurons recovered to the normal range, but a considerable number of neuronal
bodies were dispersed outside the normal PCA area. This indicates misdirected
reinnervation to the PCA muscle by motoneurons that originally served other
laryngeal muscles. In the freezing injury, effective vocal cord movement finally
recovered after 6 months. At this time, EMG showed a normal pattern, although
a
relatively small amount of misdirected neurons was observed. DISCUSSION:
Functional recovery of vocal cord motion does not occur following neurorrhaphy.
Prominently disorganized arrangement of laryngeal motor neurons was observed in
the horseradish peroxidase study. This suggests that inappropriate reinnervation
develops in spite of reapproximation and suturing. Altered central organization
of the motor nucleus is a significant pathogenic factor in the loss of laryngeal
muscular coordination following recurrent laryngeal nerve lesions. The degree
of
recovery is related to the mechanism of injury.
PMID: 8434719 [PubMed - indexed for MEDLINE]
43: Arch Otolaryngol Head Neck Surg. 1998 Apr;124(4):383-9.
Effect of pulsed electromagnetic stimulation on facial nerve regeneration.
Byers JM, Clark KF, Thompson GC.
Department of Otorhinolaryngology, University of Oklahoma Health Sciences
Center, Oklahoma City, USA.
OBJECTIVE: To determine if exposure to electromagnetic fields influences
regeneration of the transected facial nerve in the rat. DESIGN AND METHODS: The
left facial nerve was transected in the tympanic section of the fallopian canal
in 24 rats randomly assigned to 2 groups. The cut ends of the facial nerve were
reapproximated without sutures within the fallopian canal to maximize the
potential for regeneration. Rats in the experimental group (n= 12) were then
exposed to pulsed electromagnetic stimulation (0.4 millitesla at 120 Hz) for 4
hours per day, 5 days per week, for 8 weeks. Rats in the control group (n=12)
were handled in an identical manner without pulsed electromagnetic stimulation.
Four other rats were given sham operations in which all surgical procedures were
carried out except for the actual nerve transection. Two of these rats were
placed in each group. Nerve regeneration was evaluated using electroneurography
(compound action potentials), force of whisker and eyelid movements, and
voluntary facial movements before and at 2-week intervals after transection.
Histological evaluation was performed at 10 weeks after transection. Each
dependent variable was analyzed using a 2-way analysis of variance with 1
between variable (groups) and 1 within repeated measures variable (days after
transection). RESULTS: Statistical analysis indicated that N1 (the negative
deflection of depolarization phase of the muscle and/or nerve fibers) area, N1
amplitude, and N1 duration, as well as absolute amplitude of the compound action
potentials, were all significantly greater 2 weeks after transection in the
experimental than in the control group of rats. The force of eye and whisker
movements after electrical stimulation was statistically greater in the
experimental group of rats 4 weeks after transection. Voluntary eye movements
in
the experimental group were significantly better at 5 and 10 weeks, while
whisker movements were better at 3 and 10 weeks. There was no statistical
difference between the 2 groups for any histological variable. CONCLUSION:
Results of this study indicate that pulsed electromagnetic stimulation enhances
early regeneration of the transected facial nerve in rats.
PMID: 9559684 [PubMed - indexed for MEDLINE]
44: Tierarztl Prax. 1983;11(4):483-6.
[Treatment of a navicular bone fracture in a horse with pulsing electromagnetic
field (MF therapy)]
[Article in German]
Boening KJ.
Publication Types:
Case Reports
PMID: 6658771 [PubMed - indexed for MEDLINE]
45: Brain Res. 1983 Jan 17;259(1):31-9.
Changes in the somatotopic organization of the cat lumbar spinal cord following
peripheral nerve transection and regeneration.
Lisney SJ.
Glass microelectrodes were used to record the activity of neurones in the left
dorsal horn of the L6 segment of the spinal cord of normal cats and cats in
which the left sciatic and saphenous nerves had been cut 1 or 9 months
previously. In the normal animals the receptive fields of L6 dorsal horn neurons
excited by tactile stimulation of the leg were somatotopically organized, with
neurones in the medial and central dorsal horn having receptive fields on the
distal parts of the leg, particularly the toes, and neurones in the lateral
dorsal horn having receptive fields on the proximal parts of the leg, buttock
and lower back. This somatotopy has been shown before. One month after nerve
section no cells responded to tactile stimulation of the distal leg and cells
in
the medial and central parts of the dorsal horn now had receptive fields on the
proximal leg, buttock and back. There did not appear to be any somatotopic
organization of these new receptive fields. Lateral dorsal horn neurones had
normal receptive fields. Nine months after nerve section neurones in the medial
and central parts of the lumbar dorsal horn had receptive fields on the distal
leg but they showed several abnormal features and there was no evidence of a
return of the somatotopic organization seen in normal animals. Lateral dorsal
horn cells still had normal receptive fields.
PMID: 6824934 [PubMed - indexed for MEDLINE]
46: Ann N Y Acad Sci. 1974;238:575-85.
The effects of pulsed electromagnetic energy on peripheral nerve regeneration.
Wilson DH, Jagadeesh P, Newman PP, Harriman DG.
PMID: 4548339 [PubMed - indexed for MEDLINE]
47: Otolaryngol Head Neck Surg. 1996 Mar;114(3):424-34.
Hyperbaric oxygen treatment after rat peroneal nerve transection and
entubulation.
Santos PM, Zamboni WA, Williams SL, Covey JF, Kienstra MA.
Division of Otolaryngology, Southern Illinois University, Springfield, IL 62794,
USA.
Rat peroneal nerves were transected and entubulated with a Silastic channel. The
experimental group was treated with hyperbaric oxygen to evaluate changes in
acute edema, functional recovery, and histology. Hyperbaric oxygen was
administered with 100% O2 at 2.5 atmospheres absolute for 90 minutes twice a day
for 1 week and then four times a day for 1 week. Acute edema changes based on
nerve water weight and transfascicular area measurements were greater in injured
than in uninjured nerves but demonstrated no differences between hyperbaric
oxygen-treated and -untreated groups 2, 8 and 16 days after surgery. Functional
evaluation with gait analysis demonstrated significant changes between injured
and uninjured group 1, 3, 7, and 13 weeks after injury but no differences
between hyperbaric oxygen-treated and -untreated groups. Thirteen weeks after
the initial injury, elicited muscle force measurements demonstrated no
significant improvement from hyperbaric oxygen treatment of injured nerves.
Histologic evaluation of nerve area, myelinated axon number, myelinated axon
area, myelin thickness, and blood vessel number and area revealed no significant
differences between hyperbaric oxygen-treated and -untreated groups. Hyperbaric
oxygen was not associated with improvement of nerve regeneration with any of the
outcome variables in this model.
PMID: 8649877 [PubMed - indexed for MEDLINE]
48: J Neurosci Res. 1998 Mar 15;51(6):723-34.
Axonal regrowth through a collagen guidance channel bridging spinal cord to the
avulsed C6 roots: functional recovery in primates with brachial plexus injury.
Liu S, Bodjarian N, Langlois O, Bonnard AS, Boisset N, Peulve P, Said G, Tadie
M.
Department of Neurosurgery, Hospital of Bicetre, Le Kremlin-Bicetre, France.
Intraspinal implantation of a collagen guidance channel (CGC) to promote axon
regeneration was investigated in marmosets with brachial plexus injury. After
avulsion of the right C5, C6 and C7 spinal roots, a CGC containing (group B) or
not (group A) a nerve segment, or a nerve graft (group C), was ventro-laterally
implanted into the cord to bridge the ventral horn and the avulsed C6 roots. No
spinal cord dysfunction was observed following surgery. Two months later, the
postoperative flaccid paralysis of the lesioned arm improved. In five months,
a
normal electromyogram of the affected biceps muscle was recorded in all repaired
animals. Motor evoked potentials were obtained with a mean amplitude of 13.37
+/- 13.66 microV in group A, 13.21 +/- 5.16 microV in group B and 37.14 +/-
35.16 microV in group C. The force of biceps muscle contraction was 27.33 +/-
20.03 g (group A), 24.33 +/- 17.03 g (group B) and 37.38 +/- 21.70 g (group C).
Retrograde tracing by horseradish peroxidase showed labelled motoneurons
ipsilaterally located in the C5 and C6 ventral horn, nearby the implantation
site. The mean labelled neurons was 32.33 +/- 21.13, 219.33 +/- 176.29 and 64.33
+/- 23.54 in group A, B and C respectively. Histological analysis presented
numerous myelinated and unmyelinated regenerating axons in the implant of these
animals. Statistical analysis did not show significant difference among the
three repaired groups. Our results indicate that spinal neurons can regenerate
through a CGC to avulsed nerve roots and induce motor recovery in primates.
PMID: 9545086 [PubMed - indexed for MEDLINE]
49: Plast Reconstr Surg. 1998 Nov;102(6):2072-81; discussion 2082-4.
Long-term observation of the effect of peripheral nerve injury in neonatal and
young rats.
Watanabe O, Mackinnon SE, Tarasidis G, Hunter DA, Ball DJ.
Department of Surgery, Washington University School of Medicine, St. Louis, MO,
USA.
The purpose of this study was to observe functional recovery and motoneuron
death after nerve transection-and-repair in neonatal versus young animals. One
hundred nine Lewis rats underwent posterior tibial nerve transection-and-repair
at 6 or 22 days of age. Fifty-two and fifty-seven nerves at the 6- and 22-day
times were used for endpoint analysis at 1, 3, 10, and 14 months. These
assessments included serial functional walking track analysis,
electrophysiologic studies, muscle mass evaluation, motoneuron counts with
retrograde horseradish peroxidase tracing, and histologic and morphometric nerve
analysis. Walking track analysis and nerve conduction velocity indicated
significantly poorer functional regeneration in the 6-day-old group than in the
22-day-old group. Muscle mass in the 6-day-old group did not recover as well as
in the 22-day-old group. Motoneuron numbers stained with horseradish peroxidase
were less in the 6-day-old group than in the 22-day-old group. In contrast,
morphometric analysis did not reach significance. This study suggests that the
same nerve injury sustained in a neonatal rat is less likely to demonstrate
functional recovery than one sustained in a young rat.
PMID: 9811005 [PubMed - indexed for MEDLINE]
50: J Reconstr Microsurg. 1997 Jan;13(1):31-7.
Nerve regeneration after terminolateral neurorrhaphy: experimental study in
rats.
Zhao JZ, Chen ZW, Chen TY.
Zhong Shan Hospital, Shanghai Medical University, People's Republic of China.
Four methods of nerve terminolateral neurorrhaphy (TLN) were studied in rat
experimental model. In Group A, the distal end of a severed peroneal nerve was
sutured end-to-side with an intact tibial nerve trunk, without removal of the
tibial epineurium at the suture site. In Group B, the distal end of a severed
peroneal nerve was sutured end-to-side with the intact tibial nerve trunk, with
removal of the tibial epineurium at the suture site. In Group C, a nerve segment
was bridged between the distal part of the severed peroneal nerve and the intact
tibial nerve with two end-to-side sutures. In Group D, the proximal end of a
severed tibial nerve was sutured end-to-side with the peroneal nerve trunk.
Through electrophysiologic, histologic, and ultrastructural examinations, the
following conclusions were drawn: 1. Nerve regeneration is possible after TLN.
2. The regenerating fibers after TLN have the ability to penetrate the
endoneurium, perineurium, and epineurium. 3. After different methods of TLN, the
regenerating fibers grow in both a flowing-out and a filling-in fashion.
PMID: 9120840 [PubMed - indexed for MEDLINE]
51: J Peripher Nerv Syst. 2003 Mar;8(1):17-22.
Repair of ventral root avulsion using autologous nerve grafts in cats.
Holtzer CA, Marani E, van Dijk GJ, Thomeer RT.
Neuroregulation Group, Department of Neurosurgery, Leiden University Medical
Center, Leiden, The Netherlands.
This study focuses on the capacity of motor axons to elongate from the spinal
cord through an autologous nerve graft into a spinal nerve. Applying a ventral
surgical approach, C7 ventral roots were avulsed from the cord in 12 cats.
Autologous saphenous nerve grafts were implanted into the cord at the ventral
root outlet site and coaptated to the spinal nerve. Outgrowth of axons was
studied at survival times 7, 14, 30, 60 and 120 days, respectively. The results
showed horseradish peroxidase positive motoneurons in the C7 ventral horn after
retrograde labeling, as well as neurofilament and acetylcholinesterase positive
axons in the entire trajectory from spinal cord to spinal nerve. Neurotization
of the C7 spinal nerve started between 14 and 30 days after graft implantation.
In addition electrophysiology provided evidence that outgrowing axons had
re-established functional contact with the spinodeltoid muscle at 120 days after
implantation.
PMID: 12678550 [PubMed - indexed for MEDLINE]
52: J Anat. 1997 Jan;190 ( Pt 1):51-6.
Nerve fibre regeneration across the peripheral-central transitional zone.
Carlstedt T.
Department of Orthopaedics, Karolinska Hospital, Stockholm, Sweden.
Neurons cannot negotiate an elongation across the peripheral (PNS)-central
nervous system (CNS) transitional zone and grow into or out of the spinal cord
in the mature mammal. The astrocytic rich CNS part of the spinal nerve root is
most effective in preventing regeneration even of nerve fibres from transplanted
embryonic ganglion cells. Regeneration of severed nerve fibres into the spinal
cord occurs when the transition zone is absent as in the immature animal. Before
the establishment of a transition zone there is also new growth of neuronal
processes from dorsal horn neurons distally to the injured dorsal root. Thus the
experimental strategy to reestablish spinal cord to peripheral nerve
connectivity has been to delete the transitional region and implant severed
ventral or dorsal roots into the spinal cord. Dorsal root implantation resulted
in reestablished afferent connectivity by new neuronal processes from secondary
sensory neurons in the dorsal horn of the spinal cord extending into the PNS.
The ability for plasticity in these cells allowed for a concurrent retention of
their original rostral projection. Ventral root implantation into the spinal
cord corrected deficit motor function. In a long series of experiments performed
in different species, the functional restitution was demonstrated to depend on
an initial regrowth of motor neuron axons through spinal cord tissue (CNS).
These findings have led to the design of a new surgical strategy in cases of
traumatic spinal nerve root injuries.
Publication Types:
Review
Review, Tutorial
PMID: 9034881 [PubMed - indexed for MEDLINE]
53: J Reconstr Microsurg. 2001 Nov;17(8):631-6.
Direct neurotization of muscles by presynaptic motoneurons.
Brunelli GA.
Department of Orthopaedics, University of Brescia, Italy.
The spinal cord cannot heal after severance because the central nervous system
is "non-permissive" to the advancement of axons that regrow from presynaptic
motoneurons. With the aim of overcoming paraplegia, the author has carried out
extensive experimental research since 1980, first in rats and subsequently in
monkeys, severing the cord and connecting its cephalad stump with the muscular
nerve branches by means of peripheral-nerve grafts, and using various surgical
protocols. Functional connections were established, ascertained by physical,
electrophysiologic, and histologic examinations. In this reported study, it is
demonstrated that presynaptic motoneurons are also able to reconstruct the
cytoskeleton of peripheral neurons, as well as motor end-plates. The possibility
of elongation of the axons of presynaptic motoneurons into the peripheral nerve
up to the muscle had not previously even been hypotheized. This possibility,
which has now been validated, can open the door to new surgical techniques for
spinal-cord lesions. In addition, the author presents preliminary results from
a
single human case, utilizing the surgical procedures of the preceding animal
experiments.
PMID: 11740660 [PubMed - indexed for MEDLINE]
54: Spine. 1994 Mar 15;19(6):705-9.
The effect of electromagnetic pulsing on posterior lumbar spinal fusions in
dogs.
Kahanovitz N, Arnoczky SP, Nemzek J, Shores A.
Anderson Clinic, Arlington, Virginia.
This study evaluated the effect of pulsed electromagnetic fields (PEMF) on the
healing of lumbar spinal fusions. Bilateral posterior facet fusions were
performed at L1-2 and L4-5 in 24 adult mongrel dogs. After surgery, eight
animals were stimulated with a pulse burst type signal (PEMF) for 30 minutes a
day, and eight animals were stimulated with the same PEMF for 60 minutes a day.
The remaining eight animals received no active PEMF stimulation and served as
controls. Four animals from each group were euthanatized at 6 and 12 weeks, and
the facet fusions were evaluated using high resolution radiographs and routine
histology. No statistical difference in the radiographic or histologic
appearance of the fusion mass could be detected between the stimulated and
control groups at either 6 or 12 weeks. The results of this study suggest that
PEMF stimulation had no effect on the healing of the primary posterior spinal
fusions in this controlled experimental canine model.
PMID: 8009336 [PubMed - indexed for MEDLINE]
55: Fysiatr Revmatol Vestn. 1980 Jun;58(3):137-42.
[The effect of an electromagnetic field on the neuromuscular apparatus]
[Article in Czech]
Rehacek J, Benova H, Straub J.
PMID: 7190118 [PubMed - indexed for MEDLINE]
56: Brain Res. 1997 Oct 10;771(1):31-6.
Reinnervation of denervated muscle by transplantation of fetal spinal cord to
transected sciatic nerve in the rat.
Katsuki M, Atsuta Y, Hirayama T.
Department of Orthopaedic Surgery, Asahikawa Medical College, Nishikagura,
Japan.
When motor neurons in the spinal cord are destroyed, regeneration of motor axons
and muscle reinnervation cannot be expected. We attempted reinnervation of the
denervated muscle, i.e. motor unit reconstruction, using transplantation of the
fetal spinal cord to the peripheral nerve. The sciatic nerve of an adult rat was
resected for 20 mm, and a cavity was prepared using an autologous femoral vein
at the distal stump of the nerve. The fetal spinal cord was then transplanted
into the venous cavity. After 3-6 months, no voluntary muscle contraction was
observed due to the absence of communication with the central nervous system.
However, reinnervation of the muscles via the sciatic nerve by the transplanted
spinal neurons was demonstrated electrophysiologically and histochemically. This
suggested that a motor unit can be reconstructed by fetal spinal cord
transplantation even if the original motor neurons in the spinal cord are not
available.
PMID: 9383005 [PubMed - indexed for MEDLINE]
57: Eur J Oral Sci. 1995 Oct;103(5):299-305.
The effects of low level laser treatment on recovery of nerve conduction and
motor function after compression injury in the rat sciatic nerve.
Khullar SM, Brodin P, Messelt EB, Haanaes HR.
Dept. of Oral Surgery and Oral Medicine, University of Oslo, Norway.
An animal study is presented examining the effect of low level laser (LLL)
treatment on nerve regeneration following axonotmesis. Twenty animals received
a
standardised injury to the right sciatic nerve using a time, load and length
sequence (10 min, 150 N, 5 mm) known to cause extensive axonal degeneration of
the rat sciatic nerve. The LLL treatment was administered using a hand-held
laser probe in light contact with the skin on the dorsal aspect of the hind leg
overlying the site of the axonotmesis injury to the sciatic nerve. A group of
10
animals were treated with 6J of LLL (GaAlAs 830 nm) daily for a period of 28 d.
Ten more animals were treated daily with a sham exposure setting and served as
controls. Nerve function was assessed by a recognised method of walking tract
print analysis; the "Sciatic Functional Index" (SFI), and nerve regeneration was
assessed by recording the evoked compound action potentials (cAP) in the common
peroneal nerve. At 21 d post-injury, the laser-treated group had a significantly
lower median SFI than the sham laser-treated group, indicating that the real
laser treatment had improved functional recovery in the nerve. However, no
differences were found between the evoked cAP parameters that were measured in
the laser-treated and sham laser-treated groups. Histological examination
reiterated the lack of difference between the two groups. Consequently, the
effects of LLL on recovery must have occurred more peripherally to the point
measured.
PMID: 8521121 [PubMed - indexed for MEDLINE]
58: J Bone Joint Surg Am. 1981 Apr;63(4):511-23.
Treatment of ununited tibial diaphyseal fractures with pulsing electromagnetic
fields.
Bassett CA, Mitchell SN, Gaston SR.
One hundred and twenty-five patients with one hundred and twenty-seven ununited
fractures of the tibial diaphysis were treated exclusively with pulsing
electromagnetic fields. The over-all success rate in healing of the fracture
with this surgically non-invasive out-patient method was 87 per cent. The
success rate was not materially affected by the age or sex of the patient, the
length of prior disability, the number of previous failed operations, or the
presence of infection or metal fixation.
PMID: 7217117 [PubMed - indexed for MEDLINE]
59: Izv Akad Nauk SSSR Biol. 1981 Sep-Oct;(5):774-80.
[Acute experimental emotional stress in rabbits in a modulated electromagnetic
field]
[Article in Russian]
Gorbunova AV, Petrova NV, Portugalov VV, Sudakov SK.
PMID: 7197697 [PubMed - indexed for MEDLINE]
60: Clin Orthop. 1981 Jan-Feb;(154):136-48.
Congenital "pseudarthroses" of the tibia: treatment with pulsing electromagnetic
fields.
Bassett CA, Caulo N, Kort J.
During the past seven years, 34 patients with infantile nonunions associated
with congenital "pseudarthroses" completed treatment with pulsing
electromagnetic fields (PEMFs). An analysis of results reveals that 17/34 (50%)
have achieved complete healing with biomechanically sound union and radiographic
demonstration of remedullarization. Union with function, i.e., healing with
continued need for protection, was achieved in 7/34 (21%). Failure was the
outcome in 10/34 patients (29%). Most of these occurred in males with a history
of early fracture (less than 1 year) and with spindled, hypermobile lesions
(Type III). During the early period of the study, PEMFs were the sole means of
treatment. After a "coil effect" had been demonstrated, surgical realignment,
immobilization and grafting were combined with PEMF treatment. Fundamentals of
orthopedic management developed by the larger experience with adult nonunions
were found to apply equally to infantile nonunions treated with PEMFs. These
include effective immobilization of the fracture site and controlled "stress
working" during recovery to facilitate gradual remodeling. PEMFs have been
demonstrated to be a potentially useful adjunct in the orthopedic surgeon's
armamentarium for treating infantile nonunions (congenital "pseudarthroses").
PMID: 6781806 [PubMed - indexed for MEDLINE]
61: Equine Vet J. 1989 May;21(3):201-5.
A preliminary investigation of the effect of selected electromagnetic field
devices on healing of cannon bone osteotomies in horses.
Sanders-Shamis M, Bramlage LR, Weisbrode SE, Gabel AA.
Department of Clinical Sciences, Ohio State University, College of Veterinary
Medicine, Columbus 43210.
The effect of electrical stimulation by means of selected electromagnetic field
devices on healing of cannon bone osteotomies in horses was examined. The
defects were created as 3 cm x 1 mm longitudinal osteotomies through the dorsal
cortices of the mid-metacarpi/metatarsi of adult horses. This type of defect
would asses bone healing in a situation similar to an acute, stable fracture of
the cortex. Three electromagnetic devices of different design were tested in
three different groups of horses. Healing was evaluated radiographically and
histologically. Results showed that osteotomies treated with the electromagnetic
devices healed similarly to untreated controls. Our conclusion is that the
electromagnetic devices studied did not have a local effect on the repair
process of an acute, stable, osseous defect.
PMID: 2731509 [PubMed - indexed for MEDLINE]
62: Zh Ushn Nos Gorl Bolezn. 1980 May-Jun;(3):51-3.
[Use of a low-frequency pulsing electromagnetic field in treating inflammatory
diseases of the ENT organs]
[Article in Russian]
Ozinkovskii VV.
Publication Types:
Case Reports
PMID: 7385978 [PubMed - indexed for MEDLINE]
63: J Physiol. 2001 May 1;532(Pt 3):835-49.
Size of myelinated nerve fibres is not increased by expansion of the peripheral
field in cats.
Gordon T, Rafuse VF.
Department of Pharmacology, Division of Neuroscience, University of Alberta,
Edmonton, Alberta, Canada T6G 2H7. tessa.gordon@ualberta.ca
This study tests the hypothesis that target size regulates the size of
myelinated sensory and motor fibres in peripheral nerves. Cat medial
gastrocnemius (MG) muscles were partially denervated and the size of the
remaining nerve fibres that sprouted was examined 6.4 +/- 0.9 months later to
determine whether nerve fibre size increased with target size.
Electrophysiological and morphometric analyses were used to quantify myelinated
nerve fibre size. Charge measurements from dorsal and ventral roots were used
to
electrophysiologically quantify the relative number of cut nerve fibres and the
average size of the remaining intact sensory and motor nerve fibres. Medial
gastrocnemius muscle and motor unit forces provided indirect measurements of the
increase in target size. Conduction velocities and amplitude of unitary action
potentials of motor nerve fibres innervating single motor units were also
measured after partial denervation. Electrophysiological measurements of nerve
fibre size and morphometric measurements of outer fibre perimeters and fibre
areas concurred and demonstrated that myelinated nerve fibres supplying
partially denervated MG muscles did not increase in size in parallel with the
increase in the target size. Thus, unlike non-myelinated nerve fibres, the size
of myelinated nerve fibres does not increase as target size increases.
Retrograde control of size in non-myelinated but not in myelinated nerve fibres
demonstrates differences in plasticity of neurons in the somatic and autonomic
nervous systems.
PMID: 11313450 [PubMed - indexed for MEDLINE]
64: Ann Otol Rhinol Laryngol. 1997 Jun;106(6):506-12.
End-to-side neurorrhaphy resulting in limited sensory axonal regeneration in a
rat model.
Tarasidis G, Watanabe O, Mackinnon SE, Strasberg SR, Haughey BH, Hunter DA.
Department of Otolaryngology-Head and Neck Surgery, Washington University School
of Medicine, St Louis, Missouri 63110, USA.
This study evaluated reinnervation of an end-to-side neurorrhaphy and the
resultant functional recovery in a rat model. The cut distal posterior tibial
nerve was repaired to the side of an intact peroneal nerve. In one group, the
epineurium of the peroneal nerve was left intact; in another group, the
epineurium was stripped; in the third experimental group, a perineurial slit was
created. Evaluations included walking track analysis, nerve conduction studies,
muscle mass measurements, retrograde nerve tracing, and histologic evaluation.
Walking tracks indicated poor functional recovery. No significant difference in
nerve conduction between the experimental and control groups was seen.
Gastrocnemius muscle mass measurements revealed no functional recovery in the
end-to-side groups. Retrograde nerve tracing revealed minimal staining of motor
neurons. However, sensory neuronal staining of the dorsal root ganglia occurred
in all groups. Histology revealed minimal myelinated axonal regeneration. These
results suggest that predominantly sensory neural regeneration occurs in an
end-to-side neurorrhaphy at an end point of 16 weeks.
PMID: 9199612 [PubMed - indexed for MEDLINE]
65: Plast Reconstr Surg. 1998 Aug;102(2):430-6; discussion 437-8.
Motor versus sensory neuron regeneration through collagen tubules.
Madorsky SJ, Swett JE, Crumley RL.
Department of Otolaryngology-Head and Neck Surgery, University of California
Irvine, Orange 92868, USA.
Differences in regeneration of sensory and motor nerves were studied in rats to
determine the effects of entubulation with collagen conduits. The rat sciatic
nerve was repaired either with a 10-mm saline-filled gap or with a no-gap
end-to-end repair cuffed within collagen tubules. These repairs were compared
with the standard epineurial repairs. The populations of regenerated motor and
sensory neurons in the peroneal nerves of all repairs were compared against the
populations of normal peroneal neurons using horseradish peroxidase retrograde
labeling. The epineurial repair resulted in regeneration of 65 percent (409 +/-
150) of motor neurons and 79 percent (2127 +/- 516) of sensory neurons (n = 6).
The no-gap end-to-end repair in a collagen tubule resulted in regeneration of
53
percent (338 +/- 203) of motor and 70 percent (1893 +/- 794) of sensory neurons
(n = 7). In the 10-mm gap repair, only 6.2 percent (39 +/- 18) of motor neurons
but 63 percent (1710 +/- 557) of sensory neurons regenerated (n = 5). These
results show that collagen entubulation supports nerve regeneration in
end-to-end nerve repairs comparably to standard epineurial suture repairs. With
the 10-mm gap repairs in collagen tubules, sensory neurons regenerated
consistently better than motor neurons in the same environment. Therefore,
intrinsic differences exist between motor and sensory neuron regeneration in the
same nerve.
PMID: 9703080 [PubMed - indexed for MEDLINE]
66: J Neurophysiol. 1995 Feb;73(2):651-61.
Rescue of motoneuron and muscle afferent function in cats by regeneration into
skin. I. Properties of afferents.
Johnson RD, Taylor JS, Mendell LM, Munson JB.
Department of Neuroscience, University of Florida, Gainesville 32610-0244, USA.
1. In this study we investigate the peripheral receptive field properties and
spinal cord connections of low-threshold muscle afferent fibers
cross-regenerated into the skin to determine whether a cutaneous target can
rescue physiological functions lost after chronic axotomy. 2. In adult cats the
medial gastrocnemius (MG) muscle nerve was coated with the distal cut end of
either the caudal or lateral cutaneous sural nerves and allowed to regenerate
into the hairy skin (postoperative period 6-30 mo). During terminal acute
experiments we made recordings of single MG afferent fibers in dorsal root
filaments and peripheral nerve. Conduction velocity and receptive field
characteristics were determined for each fiber. In addition, the MG nerve was
stimulated to elicit cord dorsum potentials and monosynaptic excitatory
postsynaptic potentials (EPSPs) in heteronymous motoneurons. As controls,
studies were carried out after MG nerve axotomy (postoperative period 2.5-12
mo). 3. After innervation of the skin, MG muscle afferent fibers exhibited
firing characteristics and proximal segment conduction velocities like those of
normal MG afferents. Responses to skin and hair stimulation consisted primarily
of slowly adapting, stretch-sensitive, and steady discharge patterns, all common
in normal muscle afferents but not in cutaneous afferents. These properties were
observed despite the innervation of touch domes and single hairs, suggesting
that the peripheral physiology of muscle afferents is a function of the axonal
membrane and is not respecified by a cutaneous target and/or receptors. 4. Cord
dorsum potentials were characteristic of those elicited by intact muscle
afferents rather than skin afferents and showed recovery of configurations lost
after chronic axotomy. 5. The monosynaptic EPSPs elicited in lateral
gastrocnemius-soleus motoneurons also recovered from the reduction in amplitude
observed after chronic axotomy. The configurations of these EPSPs were
characteristic of muscle afferents rather than skin afferents. 6. These
experiments demonstrate that the peripheral and central physiological properties
of muscle afferents are rescued from the axotomy state if the afferents are
allowed to reinnervate skin. We found no evidence that respecification had
occurred to bring the function of muscle afferents into accord with the new
cutaneous target.
PMID: 7760124 [PubMed - indexed for MEDLINE]
67: JAMA. 1982 Feb 5;247(5):623-8.
Pulsing electromagnetic field treatment in ununited fractures and failed
arthrodeses.
Bassett CA, Mitchell SN, Gaston SR.
Pulsing electromagnetic fields (PEMFs) induce weak electric currents in bone by
external coils on casts or skin. This surgically noninvasive, outpatient method,
approved by the Food and Drug Administration in November 1979, produced
confirmed end results in 1,007 ununited fractures and 71 failed arthrodeses,
worldwide. Overall success at Columbia-Presbyterian Medical Center was 81%;
internationally, 79%; and in other patients in the United States, 76%. Treatment
with PEMFs was effective in 75% of 332 patients (a subset) with an average
4.7-year disability duration, an average of 3.4 previous operative failures to
produce union, and a 35% rate of infection. Eighty-four percent of carpal
naviculars and 82% of femoral neck-trochanteric nonunions were united. After
attempted arthrodeses could not salvage a failed total-knee prosthesis, PEMFs
promoted healing in 85% of patients. When coils were unsuccessful alone,
combining them with surgical repair was effective.
PMID: 7054564 [PubMed - indexed for MEDLINE]
68: J Neurosci Res. 1999 Jan 15;55(2):230-7.
Electromagnetic fields influence NGF activity and levels following sciatic nerve
transection.
Longo FM, Yang T, Hamilton S, Hyde JF, Walker J, Jennes L, Stach R, Sisken BF.
Department of Neurology, UCSF/VAMC, San Francisco, California, USA.
LFM@itsa.UCSF.edu
Pulsed electromagnetic fields (PEMF) have been shown to increase the rate of
nerve regeneration. Transient post-transection loss of target-derived nerve
growth factor (NGF) is one mechanism proposed to signal induction of early nerve
regenerative events. We tested the hypothesis that PEMF alter levels of NGF
activity and protein in injured nerve and/or dorsal root ganglia (DRG) during
the first stages of regeneration (6-72 hr). Rats with a transection injury to
the midthigh portion of the sciatic nerve on one side were exposed to PEMF or
sham control PEMF for 4 hr/day for different time periods. NGF-like activity was
determined in DRG, in 5-mm nerve segments proximal and distal to the transection
site and in a corresponding 5-mm segment of the contralateral nonoperated nerve.
NGF-like activity of coded tissue samples was measured in a blinded fashion
using the chick DRG sensory neuron bioassay. Overall, PEMF caused a significant
decrease in NGF-like activity in nerve tissue (P < 0.02, repeated measures
analysis of variance, ANOVA) with decreases evident in proximal, distal, and
contralateral nonoperated nerve. Unexpectedly, transection was also found to
cause a significant (P=0.001) 2-fold increase in DRG NGF-like activity between
6
and 24 hr postinjury in contralateral but not ipsilateral DRG. PEMF also reduced
NGF-like activity in DRG, although this decrease did not reach statistical
significance. Assessment of the same nerve and DRG samples using ELISA and
NGF-specific antibodies confirmed an overall significant (P < 0.001) decrease
in
NGF levels in PEMF-treated nerve tissue, while no decrease was detected in DRG
or in nerve samples harvested from PEMF-treated uninjured rats. These findings
demonstrate that PEMF can affect growth factor activity and levels, and raise
the possibility that PEMF might promote nerve regeneration by amplifying the
early postinjury decline in NGF activity.
PMID: 9972825 [PubMed - indexed for MEDLINE]
69: Exp Brain Res. 1999 Mar;125(1):19-27.
Recovery of synapses in axotomized adult cat spinal motoneurons after
reinnervation into muscle.
Brannstrom T, Kellerth JO.
Department of Anatomy, Umea University, Sweden. thomas.brannstrom.us@vll.se
Peripheral axotomy of adult cat spinal motoneurons induces a marked loss of
synaptic boutons from the cell bodies and dendritic trees. The aim of the
present study was to analyze the recovery of synaptic contacts in axotomized
motoneurons following reinnervation into muscle. Adult cat spinal motoneurons
were first deprived of their muscular contacts for 12 weeks and, then, allowed
to reinnervate their target muscle. Two years later, regenerated motoneurons
were labeled with horseradish peroxidase to allow quantitative ultrastructural
analyses of the synaptic covering of the cell bodies and dendrites. Presynaptic
boutons were classified according to their size and the shape of their synaptic
vesicles. Results show that a recovery of synaptic covering occurs in the
axotomized neurons after muscle reinnervation, but it affects various bouton
types to different degrees. The number of S-type boutons synapsing with the soma
was 70% higher after reinnervation than at 12 weeks after axotomy, while the
number of F-type boutons had increased by only 13%. Compared with the normal
situation, the number of S-type boutons synapsing with the proximal dendrites
increased from 82% at 12 weeks after axotomy to 180% in the reinnervated state.
In conclusion, in adult cat spinal motoneurons, the reestablishment of muscular
contact is followed by a normalization of some of the synaptological changes
induced by a prolonged state of axotomy. In certain respects restitution is
incomplete, but in others it results in overcompensation.
PMID: 10100972 [PubMed - indexed for MEDLINE]
70: J Neurocytol. 2001 Nov;30(11):917-26.
Neurofilamentous hypertrophy of intramedullary axonal arbors in intact spinal
motoneurons undergoing peripheral sprouting.
Havton LA, Kellerth JO.
Department of Neurology and Brain Research Institute, Neurologic Rehabilitation
and Neural Repair Programs, University of California, Los Angeles, CA.
90095-1769, USA. LHavton@mednet.ucla.edu
An incomplete motor nerve injury or a partial loss of motoneurons leads to a
partial denervation of skeletal muscle. As part of a compensatory response, the
remaining intact motoneurons undergo peripheral sprouting and increase their
motor unit size. Our knowledge about the responses in the more proximal parts
of
these sprouting motoneurons is sparse, however. We investigated the effects of
an incomplete transection of the medial gastrocnemius (MG) nerve in the adult
cat on the morphology of the intramedullary axon and axon collateral systems of
the remaining intact MG motoneurons. At twelve weeks following the partial
transection of the MG nerve, intracellular recording and labeling techniques
were used to deposit horseradish peroxidase into single intact MG motoneurons
for detailed morphological studies. The light microscopic appearance and caliber
of the intramedullary stem motor axons of the intact MG motoneurons were
indistinguishable from controls. The number and size of the intramedullary
motoraxon collateral systems were also unchanged. However, frequent and marked
hypertrophy of the distal portions of the motoraxon collaterals was encountered.
Electron microscopic studies of the hypertrophied collaterals demonstrated
abnormal accumulations of disorganized neurofilaments arranged in bundles or
whorls. The morphological changes were indistinguishable from the
neurofilamentous hypertrophy that has previously been reported in Wallerian
degeneration, in experimental and human motor neuron disease and in some
regenerating axonal processes of spinal motoneurons. We conclude that,
neurofilamentous hypertrophy of the intramedullary arbors of motor axons may
also be part of a reactive and non-degenerative response in intact motoneurons
undergoing compensatory peripheral sprouting.
PMID: 12373099 [PubMed - indexed for MEDLINE]
71: Neurosci Lett. 1980 Aug;19(1):33-7.
Non-selective distribution of hypoglossal nerve fibers after section and
resuture: a horseradish peroxidase study in the cat.
Mizuno N, Uemura-Sumi M, Matsuda K, Takeuchi Y, Kume M, Matsushima R.
The retrograde tracing method of horseradish peroxidase (HRP) was applied to
examine the process of regeneration of severed hypoglossal nerve in the cat.
After section and resuture of the hypoglossal nerve, the cats were allowed to
survive for 4-6 months. In these cats, distribution of neurons labeled with HRP
injected into the genioglossus muscle was examined and compared with that in the
normal cat. In the operated cats, labeled genioglossus motoneurons were
scattered within all subdivisions of the hypoglossal nucleus, indicating
non-selective distribution of regenerating hypoglossal nerve fibers to the
lingual muscles.
PMID: 7052512 [PubMed - indexed for MEDLINE]
72: Otolaryngol Head Neck Surg. 1998 Oct;119(4):337-41.
End-to-side neurorraphy: a long-term study of neural regeneration in a rat
model.
Tarasidis G, Watanabe O, Mackinnon SE, Strasberg SR, Haughey BH, Hunter DA.
Department of Otolaryngology-Head and Neck Surgery, Washington University School
of Medicine, St. Louis, Missouri, USA.
This study evaluated long-term reinnervation of an end-to-side neurorraphy and
the resultant functional recovery in a rat model. The divided distal posterior
tibial nerve was repaired to the side of an intact peroneal nerve. Control
groups included a cut-and-repair of the posterior tibial nerve and an end-to-end
repair of the peroneal nerve to the posterior tibial nerve. Evaluations included
walking-track analysis, nerve conduction studies, muscle mass measurements,
retrograde nerve tracing, and histologic evaluation. Walking tracks indicated
poor recovery of posterior tibial nerve function in the experimental group. No
significant difference in nerve conduction velocities was seen between the
experimental and control groups. Gastrocnemius muscle mass measurements revealed
no functional recovery in the experimental group. Similarly, retrograde nerve
tracing revealed minimal motor neuron staining in the experimental group.
However, some sensory staining was seen within the dorsal root ganglia of the
end-to-side group. Histologic study revealed minimal myelinated axonal
regeneration in the experimental group as compared with findings in the other
groups. These results suggest that predominantly sensory regeneration occurs in
an end-to-side neurorraphy at an end point of 6 months.
PMID: 9781986 [PubMed - indexed for MEDLINE]
73: J Peripher Nerv Syst. 1996;1(2):111-8.
Experimental surgery in spinal cord lesions by connecting upper motoneurons
directly to peripheral targets.
Brunelli GA, Brunelli GR.
Department of Orthopedics, University of Brescia Medical School, Italy.
This research was aimed at assessing the possibility to connect central
motoneurons with skeletal muscles through PNS segments bypassing a lesion of the
spinal cord. The investigation was performed in 20 non-human primates (Macaca
fascicularis). The surgical paradigm consisted of anastomosing the lateral
bundle of the spinal cord directly with the sciatic nerve of the right hindlimb,
using the peroneal nerve as a graft. The animals were followed-up clinically for
18 months; at the end of this observation period, they underwent
electrophysiological examinations before being killed. Specimens were taken from
the spinal cord, graft, sciatic nerve and potentially reinnervated muscles, and
processed for routine light microscopy and immunohistochemistry. Postoperative
mortality was fairly high (six monkeys), yet the overall outcome was regarded
as
very good because the animals were neither restrained nor intensively cared for.
Five of the surviving monkeys showed clinical, electrophysiological and
histological evidence of successful reinnervation. This research demonstrated
that upper CNS motoneurons are potentially capable of elongating neuritic
processes into the endoneural tubes of a connecting graft, up to reaching a
peripheral nerve (sciatic), and restoring functional connections with the
relevant skeletal muscles.
PMID: 10975719 [PubMed - indexed for MEDLINE]
74: J Bone Joint Surg Am. 1984 Jun;66(5):693-8.