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PubMed1980

[Principles of the automatic analysis of amplitude, transmission time, conduction velocity and refractory period of the compound nerve action potential of peripheral nerves. Results in the human sural nerve (author's transl)].

A method for the automatical determination of the amplitude, the transmission time, the conduction velocity and the refractory period of sural nerve was evaluated by help of HISTOMAT-S/MULTI 20 computer. The results of the automatical analysis were compared with those of the conventional method in 50 healthy control persons. There was no significant difference between the dates. Accuracy and correctness were exactly in the same range, but the investigation time of the analysis by help of a computer is much shorter.

Action Potentials↗
PubMed1999

Satellite-cell-derived nerve growth factor and neurotrophin-3 are involved in noradrenergic sprouting in the dorsal root ganglia following peripheral nerve injury in the rat.

Injury to a peripheral nerve induces in the dorsal root ganglia (DRG) sprouting of sympathetic and peptidergic terminals around large-diameter sensory neurons that project in the damaged nerve. This pathological change may be implicated in the chronic pain syndromes seen in some patients with peripheral nerve injury. The mechanisms underlying the sprouting are not known. Using in situ hybridization and immunohistochemical techniques, we have now found that nerve growth factor (NGF) and neurotrophin-3 (NT3) synthesis is upregulated in satellite cells surrounding neurons in lesioned DRG as early as 48 h after nerve injury. This response lasts for at least 2 months. Quantitative analysis showed that the levels of mRNAs for NT3 and NGF increased in ipsilateral but not contralateral DRG after nerve injury. Noradrenergic sprouting around the axotomized neurons was associated with p75-immunoreactive satellite cells. Further, antibodies specific to NGF or NT3, delivered by an osmotic mini-pump to the DRG via the lesioned L5 spinal nerve, significantly reduced noradrenergic sprouting. These results implicate satellite cell-derived neurotrophins in the induction of sympathetic sprouting following peripheral nerve injury.

Animals↗
PubMed2005

Oxidized galectin-1 advances the functional recovery after peripheral nerve injury.

Oxidized galectin-1 has been shown to promote axonal regeneration from transected-nerve sites in an in vitro dorsal root ganglion (DRG) explant model as well as in in vivo peripheral nerve axotomy models. The present study provides evidence that oxidized galectin-1 advances the restoration of nerve function after peripheral nerve injury. The sciatic nerve of adult rats was transected and the distal nerve was frozen after being sutured into a proximal site with four epineurial stitches. An osmotic pump delivered oxidized galectin-1 peripherally to the surgical site. Functional recovery was assessed by measurement of the degree of toe spread of the hind paw for 3 months after the sciatic nerve lesion. The recovery curves of toe spread in the test group showed a statistically significant improvement of functional recovery after day 21 by the application of oxidized recombinant human galectin-1 (rhGAL-1/Ox) compared to the control group. This functional recovery was supported by histological analysis performed by light microscopic examination. The regenerating myelinated fibers at the site 21 mm distal to the nerve-transected site were quantitatively examined at 100 days after the operation. The frequency distribution of myelinated fiber diameters showed that exogenous rhGAL-1/Ox increased the number and diameter of regenerating myelinated fibers; the number of medium-sized (6-11 microm in diameter) fibers increased significantly (P<0.05). These results indicate that oxidized galectin-1 promotes the restoration of nerve function after peripheral nerve injury. Thus, rhGAL-1/Ox may be a factor for functional restoration of injured peripheral nerves.

Animals↗
PubMed1985

Activation of the alternative pathway of complement by human peripheral nerve myelin.

Destruction of peripheral nerve myelin (PNM) occurs as a consequence of a variety of pathologic conditions affecting the peripheral nervous system. In certain primary demyelinating neuropathies, several lines of evidence implicate complement in the pathogenesis of demyelination. In this study we demonstrate that human PNM consumes complement in vitro in the absence of specific antibody or C1 activation. Furthermore, activation of complement by PNM via the alternative pathway was shown by cleavage of C3 in normal human serum (NHS) and of B in C2-deficient serum (C2d-HS). Increasing consumption of hemolytic activity of C3 in Mg-EGTA-treated NHS was also noted with increasing amounts of PNM. Pronase treatment of PNM abolished C3 consumption, suggesting that a protein component exposed on the surface of myelin participated in the alternative pathway activation. When P0, the major amphiphilic glycoprotein of PNM, was incorporated into artificial lipid bilayers, the Po-liposomes consumed C3 activity in NHS containing Mg-EGTA. Pronase treatment of Po-liposomes abolished C3 consumption to the level of control liposomes, indicating that P0 was responsible for at least part of the activation seen with peripheral myelin.

Animals↗
PubMed2002

Pre-degenerated peripheral nerve extracts applied to the proximal stump of transected sciatic nerve enhance both regeneration and autotomic behavior in rats.

BACKGROUND: Peripheral nerve regeneration after traumatic injury and standard repair with a nerve autograft is often incomplete and results in neuropathic pain. Peripheral nerve extracts applied to the proximal nerve stump by means of autologous, dead-ended connective tissue chambers (deCTC) are known to accelerate the rate of axon regeneration. This study tested if such extracts would influence autotomy, which is a behavioral measure of neuropathic pain in animal models. MATERIAL/METHODS: The study was performed on Wistar rats. DeCTCs, filled with postmicrosomal fraction obtained from 7-day-predegenerated nerves (7D group) or fibrin (F group), were implanted into transected sciatic nerve. In the control group (C), sciatic nerve was transected and its distal part was removed. The self-mutilation behavior in rats was assessed daily for seven weeks after sciatic nerve transection. The onset as well as intensity of autotomy was measured. The progress of regeneration was assessed under light microscopy and histochemistry. RESULTS: The earliest onset and greatest severity of autotomy were found in the 7D group. Regeneration progress was also highest in this group. In the F group, we found weaker regeneration and less autotomy. The control group showed no regeneration, but more autotomy than the F group. CONCLUSIONS: Intensified autotomy may be the price paid for enhanced peripheral nerve regeneration after application of growth-promoting substances.

Animals↗
PubMed2004

A computational solution of mathematical model for oxygen transport in peripheral nerve.

Time-dependent transport of oxygen in a peripheral nerve by simulating oxygen release, diffusion, chemical reactions and consumption in capillaries and surrounding peripheral nerve tissue using Krogh cylinder symmetry has been studied. Radial diffusion of oxygen is from a capillary to a surrounding cylinder tissue and axial diffusion to arterial distance to veins. A monoexponential or bioexponential function characterizes the approach of the oxygen tension to a new value. The time-dependent transport of oxygen in peripheral nerve with forward and backward reactions has been considered in this mathematical model which makes it different from earlier-studied models. A numerical technique has been used to find the solution.

Blood Flow Velocity↗
PubMed1998

Multiple schwannomas in the peripheral nerves.

Multiple tumours of peripheral nerves are often seen in patients with neurofibromatosis of type 1 or 2. Multiple schwannomas may occur without other manifestations of neurofibromatosis. We have reviewed 12 patients with multiple schwannomas arising from peripheral lesions who did not fulfil the criteria for either type of neurofibromatosis. Four had spinal and one an intracranial lesion in addition to the peripheral tumours. Two patients had one and three café-au-lait spots, respectively, and another had a probable family history. The largest tumours were 45 to 250 mm in size. Three patients had been referred as having von Recklinghausen's disease. The large size of tumours, the difficulties of histological diagnosis on biopsy, and the confusion with neurofibromatosis can lead to overtreatment. Malignant change seldom, if ever, occurs in patients with multiple schwannomas.

Adult↗
PubMed1996

Magnetic resonance neurography of peripheral nerve lesions in the lower extremity.

OBJECTIVE: We describe the clinical application and utility of high-resolution magnetic resonance neurography (MRN) techniques to image the normal fascicular structure of peripheral nerves and its distortion by mass lesions or trauma in the lower extremity. METHODS: MRN images were obtained using a standard 1.5 Tesla magnet and custom built phased-array coils. Patients were imaged using T1-weighted spin echo without and with gadolinium, T2-weighted fast spin echo with fat peripheral nerve tumors (three neurofibromas and one schwannoma), two with intraneural cysts, and three with traumatic peripheral nerve lesions. Six patients with peripheral nerve mass lesions underwent surgery, thereby allowing MRN images to be correlated with intraoperative and pathological findings. RESULTS: Preoperative MRN accurately imaged the normal fascicular anatomy of peripheral nerves and precisely depicted its relation to tumor and cystic lesions. Increased signal on T2-weighted fast spin-echo and short tau inversion recovery fast spin-echo pulse sequences was seen in the peripheral nerve fascicles of patients with clinical and electrodiagnostic evidence of nerve injury. CONCLUSION: MRN proved useful in the preoperative evaluation and planning of surgery in patients with peripheral nerve lesions.

Adult↗
PubMed1997

Peripheral nerve schwannomas--an analysis of 16 patients.

16 patients with peripheral nerve neurinomas (benign schwannomas) were operated upon in our hospital between 1990-1995. The largest tumours were found on proximal segments of peripheral nerves (brachial plexus: 15 cm, sciatic nerve: 20 cm). The average duration of symptoms was 1 1/2 years (range: 3 months-15 years). Pain or painful paraesthesias were the main complaints (13/16). Postoperatively, 9 patients were painfree while 4 improved. Similarly, neurological deficits were favourably influenced by the operation: Out of 5 patients with motor deficits 4 had complete, 1 patient had partial recovery. One out of 4 patients with sensory deficits had complete recovery, 2 remained unchanged, while 1 worsened. Two patients developed new motor and 6 patients new sensory deficits, which (in the course of time) did not disappear completely. New deficits developed predominantly in patients with large tumours or longstanding symptoms. Tumour recurrences were not seen during the follow-up period of 23 months. Our findings revealed that in the majority of cases peripheral nerve neurinomas can be excised with good results. Patients should be treated by a neurosurgeon with special expertise in peripheral nerve surgery. The patient should be thoroughly informed pre-operatively about any eventual new neurological deficits following surgery.

Adult↗
PubMed1997

Dissociation of microglial activation and neuropathic pain behaviors following peripheral nerve injury in the rat.

Peripheral nerve injury commonly leads to neuropathic pain states fostered, in part, by neuroimmunologic events. We used two models of neuropathic pain (L5 spinal nerve cryoneurolysis (SPCN) and chronic constriction injury (CCI)) to assess the role of spinal glial activation responses in producing pain behaviors. Scoring of glial responses subjectively encompassed changes in cell morphology, cell density and intensity of immunoreactivity with specific activation markers (OX-42 and anti-glial fibrillary acidic protein (GFAP) for microglia and astrocytes, respectively). Glial responses were compared with tactile sensitivity (mechanical allodynia) at 1, 3 or 10 days following SPCN and with thermal hyperalgesia at 10 days in the CCI group. Neuropathic pain behaviors preceded and did not closely correlate with microglial responses in either model. Perineural application of bupivacaine prior to SPCN prevented spinal microglial responses but not pain behaviors. Spinal astrocytic responses to SPCN were early, robust and not altered by bupivacaine. The current findings support the use of bupivacaine as a tool to suppress microglial activation and challenge the putative role of microglia in initiating or potentiating pain behaviors which result from nerve injury.

Anesthetics, Local↗
PubMed1997

Lower-limb lengthening in short stature. An electrophysiological and clinical assessment of peripheral nerve function.

We assessed peripheral nerve function during and after lower-limb lengthening by callotasis in 14 patients with short stature, using motor conduction studies. Four patients with short stature of varying aetiology showed unilateral and one showed bilateral weakness of foot dorsiflexion. Both clinical and electrophysiological abnormalities consistent with involvement of the peroneal nerve were observed early after starting tibial callotasis. There was some progressive electrophysiological improvement despite continued bone distraction, but two patients with Turner's syndrome had incomplete recovery. A greater percentage increase in tibial length did not correspond to a higher rate of peroneal nerve palsy. The function of the posterior leg muscles and the conduction velocity of the posterior tibial nerve were normal throughout the monitoring period. The F-wave response showed a longer latency at the end of the bone distraction than in basal conditions; this is probably related to the slowing of conduction throughout the entire length of the nerve.

Achondroplasia↗
PubMed2005

Continuous peripheral nerve blocks in children.

In recent years, regional anaesthesia in children has generated increasing interest. Continuous peripheral nerve blocks have an important role in the anaesthetic arsenal, allowing effective, safe and prolonged postoperative pain management. Indications for continuous peripheral nerve blocks depend on benefits/risks analysis of each technique for each patient. The indications include surgery associated with intense postoperative pain, surgery requiring painful physical therapy, and complex regional pain syndrome. Continuous peripheral nerve blocks are usually performed under general anaesthesia or sedation, and require appropriate equipment in order to decrease the risk of nerve injury. New techniques, such as transcutaneous stimulation or ultrasound guidance, appear to facilitate nerve and plexus identification in paediatric patients. Nevertheless, continuous peripheral nerve block may mask compartment syndrome in certain surgical procedure or trauma. Finally, ropivacaine appears to be the best local anaesthetic for continuous peripheral nerve blocks in children, requiring low flow rate with low concentration of the local anaesthetic.

Anesthetics, Local↗
PubMed2000

Repair of peripheral nerve defects in the upper extremity.

Repair of peripheral nerve defects in the upper extremity using end-to-end coaptation is accomplished by one of four techniques: in situ mobilization, rerouting and transposition, joint positioning, and bone shortening. A key concern is the amount of tension generated when nerves are elongated to overcome a gap defect. The evidence indicates that elongation should be limited to 8% to 10% of the original length to avoid neural ischemia. It should be noted, however, that when repairs are delayed, the vascularity of nerves is increased. As a result, compared with acute injuries, chronic injuries will tolerate the same degree of elongation with less neural ischemia despite increased stiffness. The mesoneural attachments along each end of the nerve may be safely stripped to a distance of 8 to 12 cm when mobilizing the nerve. Larger nerves tolerate greater lengths of mobilization than smaller nerves. The maximum amount of mobilization that does not produce ischemia can be expressed as a ratio of the diameter of the nerve to the length mobilized and its value is 1:45. The amount of nerve mobilization required for a secondary repair may be reduced by the initial application of tension to unrepaired nerves, thereby reducing the amount of retraction. As the interval to repair increases, nerve retraction results in up to a six-fold increase in the gap defect that must be overcome. Finally recommendations exist for the repair of peripheral nerve segmental defects in the acute setting.

Algorithms↗
PubMed2006

[Peripheral nerve injury and male sexual dysfunction].

The genital organ is innervated by autonomic and somatic nerve. The former is both sympathetic and parasympathetic nerve and the later is comprised by sensory and motor fibers. The symptoms of male sexual dysfunction are sexopathy, erectile dysfunction, disorder of ejaculation and orgasm, and pianism. Not only different symptom but the same symptom can be induced by different injured nerve. The relationship between peripheral nerve injury and male sexual dysfunction should be understood correctly.

Erectile Dysfunction↗
PubMed1977

Ischaemia of peripheral nerve and muscle.

Although skeletal muscle and peripheral nerves are both resistant to ischaemia there are nevertheless many syndromes in which they are affected, either separately or together. It is frequently difficult to distinguish the effects of arterial ischaemia from those of compression, which may operate through vascular occlusion, or, in the case of peripheral nerve, by mechanical deformation of nerve fibres. A great deal has been learned from experimental models, but not all of it is applicable to the complexity of human neuromuscular ischaemia which requires further study.

Arteriosclerosis↗
PubMed1986

Morphologic and immunohistochemical features of two spontaneous peripheral nerve tumors in Wistar rats.

Morphologic features and S-100 protein immunoreactivity of a benign and malignant peripheral nerve sheath tumor were studied in two Wistar rats. Neoplasms that developed in untreated control rats from tumor bioassays were S-100 protein positive and had similar histopathologic features. Each peripheral nerve sheath tumor was encapsulated and composed of spindle cells arranged around small thin-walled blood vessels. Palisaded tumor cells were in the benign peripheral nerve sheath tumor while cells of the malignant peripheral nerve sheath tumor had cellular atypia and moderate numbers of mitoses. Ultrastructural examination of the malignant peripheral nerve sheath tumor revealed cells with external lamina and interdigitation of cytoplasmic processes. Intracytoplasmic concentric lamellae were seen; they were regularly spaced with a periodicity of about 15 nm. Such structures, indistinguishable from myelin sheaths, have not been commonly associated with peripheral nerve sheath tumors in man. Electron microscopy and immunohistochemistry were useful in the diagnosis of these tumors as Schwannomas and in differentiation from other spindle cell tumors.

Animals↗
PubMed2004

Mitchell's influence on European studies of peripheral nerve injuries during World War I.

OBJECTIVE: Describe the influence of S. Weir Mitchell's (1829-1914) work, and in particular his ideas on causalgia, on European physicians who treated peripheral nerve injuries during World War I (WWI). BACKGROUND: During the American Civil War (1861-1865), Mitchell studied peripheral nerve injuries with colleagues George Read Morehouse and William Williams Keen. Three monographs resulted from this work. All were important landmarks in the evolution of knowledge of peripheral nerve injuries. A subsequent occasion to improve knowledge came in WWI. METHODS: The most important European monographs or series on peripheral nerve injuries from WWI were studied with special interest in references to causalgia and Mitchell's works on peripheral nerve injuries. We included works by Tinel, Athanassio-Benisty, Purves-Stewart & Evans and Carter, Foerster and Oppenheim. RESULTS: Tinel and Athanassio-Benisty provided the most detailed information on peripheral nerve injuries and causalgia and often referred to Mitchell. Both mentioned a possible sympathetic origin. Athanassio-Benisty described tremor and other movement disorders in relation to causalgia. Purves-Stewart and Evans mentioned Mitchell and causalgia in the second edition of their book. They advocated the term "thermalgia." Carter, who had access to data of many cases, concentrated his work on causalgia, referring to Mitchell. Foerster provided data of a great number of peripheral nerve injuries, but did not refer to Mitchell. However, he described the symptoms of causalgia cursorily, applying the term Reflexschmerz (reflexpain). Oppenheim was particularly interested in muscle innervation and referred to Mitchell with respect to hypertrichosis and glossy skin. Oppenheim did not use the term causalgia, although he described the syndrome in some of his patients. It wasn't until around 1920 that German physicians devoted significant attention to causalgia and began using the term. CONCLUSION: Knowledge of peripheral nerve injuries was greatly advanced during and after WWI. Mitchell's influence was mainly found in the French medical literature, where his findings provided the basis for further research on the origin of causalgia. In England, Mitchell and causalgia were also well-known. We found evidence to suggest that some of the English knowledge came from French physicians. German physicians described the symptoms of causalgia, but did not use the term, nor did they refer to Mitchell. This variation in Mitchell's influence by country probably reflects the fact that Mitchell's Injuries of nerves and their consequences was translated into French but not German.

Biomedical Research↗