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PubMedDate not supplied

[Post-gunshot wound lesions of the peripheral nerves which may be prevented with adequate primary surgical wound care].

The retrospective study includes 24 wounded persons with iatrogenic peripheral nerve lesion and 94 wounded whose neural damage occurred due to peripheral nerve engagement in scar tissue after main artery reconstruction, missile bone fracture or after soft tissues defects covering by Tiersch transplants. The authors analyzed frequency and localization of these lesions, intraoperative findings, applied operative procedures and clinical findings during preoperative follow-up. It is recommended to create the new bad for exposed peripheral nerve from adjacent muscles as part of primary surgical wound treatment. This procedure eliminates the risk of subsequent epineural scar formation in all situations that have been described (soft tissue defects, artery reconstruction and bone fracture) and makes the later operations on peripheral nerves unnecessary.

Cicatrix↗
PubMed1999

Hereditary absence of complement C5 in adult mice influences Wallerian degeneration, but not retrograde responses, following injury to peripheral nerve.

We have examined the role of complement component 5 (C5) in peripheral nerve fiber degeneration and regeneration, as well as in glial and neuronal cell responses in the central nervous system (CNS). Adult congenic mice lacking C5 (C5(-)) and the corresponding normal strain (C5(+)) were used. Macrophage recruitment as well as axonal and myelin sheath elimination were delayed from 1 to 21 days postinjury in C5(-) mice compared to the C5(+) group after sciatic nerve crush. Despite this, recovery of motor function was not delayed. In the CNS, microglial cells and astrocytes responded in the same way from 3 to 21 days after sciatic nerve injury in C5(-) and C5(+) mice, and the extent of neuron death following hypoglossal nerve avulsion was the same in both groups. These findings suggest that C5 and/or its derivatives play an important role in initiating the recruitment of macrophages to the injured nerve and, probably indirectly, in early remyelination of regenerating axons, but does not influence the longterm functional restoration or axotomy-induced nerve cell death. C5-derived molecules do not appear to participate in central glial cell responses to peripheral nerve injury. These findings elucidate new aspects on the functional role of the complement system in the peripheral nervous system following peripheral nerve injury.

Animals↗
PubMed1998

[Development of peripheral nerve surgery].

In the submitted review the author deals with the development of peripheral nerve surgery (PN) from ancient times to the present time incl. hithero unpublished details. He analyses in great detail the period of the last 40 years which is divided into three stages--the mechanical, biological period and the period of neurotrophism. From the Second World War to the sixties the period bears the term mechanical. The results of reinnervation during this period were not satisfactory as the nerves were connected without the use of a microscope, in major defects they were connected under considerable traction and the only criterion was the resistance against dehiscence. Significant improvement of results of regeneration of PN was recorded during the biological period. Mechanical ideas were overcome and biological and physiological reactions of the peripheral nerves were taken into account. Suture of nerves under traction was refuted and into clinical practice the surgical microscope, microsurgical technique and microsurgical autotransplantation with a nervous graft were introduced. The anatomical structure of the nerve with a plexiform pattern of the fascicles became however the limitation of surgical methods. After discovery of NGF (nerve growth factor) we can speak of the onset of a new period, neurotrophism. In laboratory experiments many substances are studied and theoretically new non-surgical possibilities how to promote regeneration lie ahead. However they cannot be applied yet in clinical practice. In injuries of peripheral nerves the only correct reconstruction method is still microsuture of the nerve and in case of losses microsurgical autotransplantation using a nerve graft.

History, 18th Century↗
PubMed1998

Peripheral nerve blocks improve analgesia after total knee replacement surgery.

UNLABELLED: Total knee replacement (TKR) produces severe postoperative pain. Peripheral nerve blocks can be used as analgesic adjuncts for TKR, but the efficacy of femoral nerve blocks alone is controversial. The sciatic nerve innervates posterior regions of the knee; thus, performance of both sciatic and femoral nerve blocks may be necessary to improve analgesia after TKR. We performed this study to determine whether peripheral nerve blocks improve analgesia after TKR. In a randomized, double-blind fashion, 36 patients undergoing TKR received either femoral, sciatic-femoral, or sham nerve blocks after a standardized spinal anesthetic. Further postoperative analgesia was provided by patient-controlled i.v. morphine and ketorolac. Pain at rest and with physical therapy, morphine use, nausea, pruritus, sedation, and patient satisfaction were assessed. Patients receiving peripheral nerve blocks reported better analgesia at rest for at least 8 h after transfer to the hospital ward (P < 0.05). Morphine use was decreased by approximately 50% in the peripheral nerve block groups until the second postoperative day (P < 0.02). Side effect profiles and patient satisfaction were similar between groups. We conclude that femoral nerve blocks improve analgesia and decrease morphine use after TKR. The addition of a sciatic nerve block to the femoral nerve block did not further improve analgesic efficacy. IMPLICATIONS: Performance of femoral nerve blocks improves analgesia and decreases the need for morphine after total knee replacement surgery. The addition of a sciatic nerve block to the femoral nerve block does not provide additional benefits.

Aged↗
PubMed2000

Imaging the brachial plexus and peripheral nerves in infants and children.

Imaging of the brachial plexus and peripheral nerves is challenging in the pediatric patient. Magnetic resonance imaging is the modality of choice as it is not invasive and demonstrates proximal and distal lesions. This may be used to detect nerve root avulsions, nerve ruptures, pseudo-meningoceles, brachial plexus scarring, post-traumatic neuromas, brachial plexus edema, spinal cord damage, abnormalities of the shoulder joint, trauma, neoplasms, and infection. Imaging allows diagnosis and careful preoperative evaluation of children suffering from brachial plexus injuries and peripheral nerve disorders.

Brachial Plexus↗
PubMed1986

Management of peripheral nerve injuries.

The choice between repair or reconstruction in the management of nerve injury, and the determination on timing and the type of neurorrhaphy technique are clinical decisions that should be based on thorough understanding of the pathophysiology of nerve injury, the physiology of nerve healing, and the anatomy of peripheral nerves. The formulation of a treatment plan should be individualized.

Arm Injuries↗
PubMed1983

Nearest-neighbor distance of intermediate filaments in axons and Schwann cells. Distinction between axons and schwann cell processes in the denervated and reinnervated peripheral nerves.

To distinguish axons from Schwann cell processes in the denervated (Büngner's bands) and reinnervated peripheral nerves, the nearest-neighbor distance of intermediate filaments (NND) was measured in axons and Schwann cells from denervated and subsequent regenerating peripheral nerves. It was revealed that the NND was much larger in regenerating axons (41.9 +/- 14.1 nm) than in Schwann cell processes (23.1 +/- 7.1 nm in regeneration and 19.7 +/- 5.8 nm in denervation). In addition, the NND was also measured in the normal adult and developing peripheral nerves, and it became clear that in all cases the NND in axons (29.0-41.9 nm) was larger than in Schwann cells (19.7-23.1 nm). Thus, it can be generally considered that the NND is larger in axons than in Schwann cells. This fact can be used for the distinction between axons and Schwann cell processes, when the latter have a profile similar to that of the former as in Büngner's bands and in the regenerating nerves.

Animals↗
PubMed2001

High-concentration tetracaine for the management of trigeminal neuralgia: quantitative assessment of sensory function after peripheral nerve block.

OBJECTIVE: This study examined the effects of peripheral nerve block with high-concentration tetracaine for the management of trigeminal neuralgia, and evaluated sensory function by measuring the postblock current perception threshold. METHODS: Five infraorbital nerve blocks were performed in five elderly patients using 4% tetracaine dissolved in saline or 0.5% bupivacaine. The authors used a neurometer to compare postblock current perception threshold between the block side and the contralateral healthy side, and used cold tests to assess the sensory level. RESULTS: The analgesic effect of tetracaine blocks continued for a median period of 2 months (range, 1.5-months). Hypesthesia was observed in all patients after the block but resolved within a mean period of 2.2 weeks. Although differences in current perception threshold values between sides were not significant in any patient, block-side values in two patients were clinically higher than contralateral-side values (250 vs. 5 Hz) for some time before returning to normal levels. CONCLUSION: Peripheral nerve block with high-concentration tetracaine is a relatively safe and useful technique in the management of trigeminal neuralgia, particularly among older patients and those with systemic problems.

Aged↗
PubMedDate not supplied

Double-injection method using peripheral nerve stimulator is superior to single injection in axillary plexus block.

BACKGROUND AND OBJECTIVES: Axillary block using a single-injection method does not always provide effective analgesia. This study examined whether a double axillary block injection technique is superior to a single injection axillary block. METHOD: Fifty patients were randomly allocated to two groups. In group I (single injection), the whole volume of local anesthetic (0.7 mL/kg) was injected after locating only one of the median, radial, or ulnar nerves. In group 2 (double injection), half of the volume was injected after locating one nerve and the other half after locating another peripheral nerve. Bupivacaine 0.5% and prilocaine 1% (1:1 volumes) were used as local anesthetic. A peripheral nerve stimulator was used to identify the nerves. Sensory block of seven nerves and motor block of four nerves were tested after 40 minutes. RESULTS: Complete sensory and motor block (scores 2 or 3 on scale 0-3) in all four main nerves (median, ulnar, radial, musculocutaneous) was achieved in 3 (12%) versus 20 (80%) patients in groups 1 and 2, respectively (P = .000001). Primary success rate (no need for supplemental nerve block) was 52% in group 1 and 92% in group 2 (P = .0016). CONCLUSIONS: A double-injection method in axillary block provides excellent analgesia and motor block compared with a single-injection method. Moreover, the need for supplemental nerve blocks is significantly decreased.

Adult↗
PubMed1992

[Microsurgical and histological observations in schwannoma of peripheral nerves].

From 1986 to 1991, eight patients with benign schwannomas (neurilemomas) of peripheral nerves underwent tumor resection. In six of eight cases, microsurgical dissection revealed one or several nerve fascicles "disappearing" in the center of the schwannoma. Therefore, these fascicles had to be removed along with the tumor. This observation contradicts the current opinion that enucleation of benign schwannomas is usually straightforward and possible without fascicular damage. Interestingly, the resection of fascicles did not create additional neurological deficits. For functional reasons, partial nerve grafts bridging the resulting fascicular defects were considered appropriate in two cases. Tumors of peripheral nerves should be treated by surgeons familiar with microsurgical operative techniques.

Adult↗
PubMed1975

Penetration of C14-labelled rifampicin into primate peripheral nerve.

The penetration of C14 Rifampicin into various tissues, but particularly peripheral nerve, has been studied in the monkey. Penetration into the substance of peripheral nerve internal to the epineurial covering was demonstrated and the significance of this in relation to the treatment of leprosy is discussed.

Animals↗
PubMed2002

Pre-, intra-, and postoperative electrophysiologic analysis of the recovery of old injuries of the peripheral nerve and brachial plexus after microsurgical management.

This prospective electrophysiologic study compares the analysis of the pre-, intra-, and postoperative results of 38 surgically treated patients suffering from old injuries of the peripheral nerve (n=28) and brachial plexus (n=10). The period from injury until surgery for the peripheral nerve group ranged from 1.2 to 50 years and, in the brachial plexus group, from 1.2 to 12 years. A statistical electrophysiologic analysis was done: 1) to compare intraoperative amplitude and latency changes of the compound muscle action potential (CMAP) at commencement and on completion of surgery; 2) to compare amplitude and latency changes of CMAP and recruitment (voluntary muscle activity) prior to and 1 year after surgery. In the peripheral nerve group, intraoperative electrophysiologic recordings of CMAP showed a low amplitude at the onset of surgery and significant increase on completion of surgery after neurolysis (p=0.0001) with improvement of latency (p=0.001). The statistical analysis of recruitment of muscles showed a 60 percent improvement 1 year after neurolysis (27 patients) and good recovery after nerve graft (1 patient). There were no statistically significant differences in results in patients under 40 years of age, compared to those above 40 years of age. In the brachial plexus group, statistical analysis of recruitment showed voluntary muscle activity in 45 percent of muscles 1 year after neurolysis (7 patients) and in 42 percent of muscles after nerve graft and neurotization (3 patients). Intraoperative electrophysiologic findings provide useful information during surgery for old peripheral nerve and brachial plexus injury. Intraoperative and postoperative electrophysiologic analyses suggest that the viability of the old injured nerve tissue is longer than previously considered, thus providing a longer period of time in which nerve recovery can occur.

Action Potentials↗
PubMed2001

Inhibition of the I(h) current in isolated peripheral nerve: a novel mode of peripheral antinociception?

Although the alpha2-adrenergic agonist clonidine has been shown to promote peripheral antinociception, its mechanism of action has not yet been clearly elucidated. By the use of the sucrose-gap method, we have shown that in C fibers of the rabbit vagus nerve, clonidine at micromolar concentrations enhances activity-dependent hyperpolarizations generated by the Na+-K+ pump during and after repetitive stimulation. Similar results were obtained with 10 microM of ZD 7288, a specific blocker of the hyperpolarization-activated cation current (I(h)) and with 2 mM of Ba2+ that blocks the inwardly rectifying potassium current (I(KIR)). Furthermore, clonidine had no added effect on the ZD 7288-induced response, whereas it produced a marked enhancement of Ba2+induced response. From these results, it can be concluded that clonidine enhances activity-dependent hyperpolarization by inhibiting the current I(h). We propose that clonidine, by increasing the threshold for initiating the action potential, induces a slowing or block of conduction and that this mechanism is the origin of the clonidine-induced antinociception. Finally, this study suggests a novel role for inwardly rectifying hyperpolarization-activated conductances in peripherally mediated antinociception.

Action Potentials↗
PubMedDate not supplied

[Palpable orbital subcutaneous masses in chronic inflammatory demyelinating polyneuropathy. MRI and neurophysiological study of multiple peripheral nerve swelling].

We report a 46-year-old woman with chronic inflammatory demyelinating polyneuropathy (CIDP) in whom swelling of the first branch of the trigeminal nerves in the bilateral orbits were observed as subcutaneous masses in the upper eyelids. The disease developed when the patient was 33 years old, and weakness of the four limbs, double vision, unilateral hypoglossal neuroparalysis, and unilateral facial paralysis frequently occurred during the course of the illness. On nerve conduction studies, conduction block was detected in the motor nerves. Steroid therapy and immunoglobulin treatment improved the symptoms. At 43 years old, subcutaneous phymas were noted in the bilateral upper eyelids, and fat-suppressed MRI detected the phymas localized along the upper region of the superior straight muscle in the bilateral orbits, and the muscles were slightly compressed downward. The masses branched in the orbits, and were diagnosed as nerve swelling of the supraorbital nerve, the first branch of the trigeminal nerve. Fat-suppressed MRI also identified nerve swelling of the extracranial maxillary and mandibular nerves. However, the patient had no subjective sensory disturbance in the trigeminal nerve region. Blink reflex did not induce R1 and R2 exhibited low amplitude and delayed latency. MRI confirmed asymmetric nerve swelling in the regions of the bilateral median nerves with motor nerve conduction block. Lumbar MRI detected nerve swelling in the peripheral nerves distant from the lumbar ganglion. MRI detected no nerve swelling in the arachnoid space such as the cervical cord, thoracic cord, or cauda equina. Aggravation of CIDP was treated with steroids and immunoglobulin. Diplopia occasionally appeared, but was not consistent with aggravation of CIDP. The bilateral supraorbital nerves remained unchanged for three years on MRI.

Chronic Disease↗
PubMed2003

p15INK4b, p14ARF, and p16INK4a inactivation in sporadic and neurofibromatosis type 1-related malignant peripheral nerve sheath tumors.

PURPOSE: Malignant peripheral nerve sheath tumor (MPNST) can arise sporadically or in association with neurofibromatosis type 1. Deletions at the 9p21 locus have been reported in these tumors. To additionally characterize the status of this chromosomal region, in this study we performed a comprehensive, mostly PCR-based molecular analysis of the three tumor suppressor genes p15(INK4b), p14(ARF) and p16(INK4a) located at the 9p21 locus in 26 cryopreserved MPNSTs. EXPERIMENTAL DESIGN: Fourteen neurofibromatosis type 1-related and 12 sporadic cases were investigated for homozygous deletion coupled with fluorescent in situ hybridization, promoter methylation, and mutational analysis, as well as m-RNA expression. RESULTS: The results showed that an inactivation of one or more genes occurred in 77% of MPNSTs and was mainly achieved through homozygous deletion (46%), which, in turn, encompassed all of the three tandemly linked genes in 83% of the deleted cases. Promoter methylation was at a less extent involved in gene silencing (18%), and no mutations were found. Loss of function at DNA level strongly correlated with loss of mRNA expression accounting for 80% of the cases. Because of the close relationship between p14(ARF) and TP53 and between p15(INK4b)/p16(INK4a) and Rb, these results support a model of a coinactivation of TP53 and Rb pathways in 75% of MPNSTs, with functional consequences on cell growth control and apoptosis. CONCLUSIONS: The inactivation of the 9p21 locus is a frequent and peculiar hallmark of MPNST genetic profile leading also to an impaired apoptosis that could be taken into account in treatment planning of these tumors.

Adult↗
PubMed1982

The effect of peripheral nerve lesions and of neonatal capsaicin in the rat on primary afferent depolarization.

1. In anaesthetized adult rats with intact peripheral nerves, a conditioning orthodromic volley in myelinated afferents produces a prolonged increase in the excitability of the terminals of the afferents which have carried the orthodromic volley and in the terminals of their passive neighbours. This phenomenon, primary afferent depolarization, p.a.d., is shown by the antidromic stimulation of afferents with a micro-electrode in the dorsal horn and by recording the antidromic volley on a cut peripheral nerve.2. If a peripheral nerve is cut and ligated, the size of the myelinated afferent volley generated by stimulation proximal to the cut and measured on dorsal roots is not affected for 14 days after the cut (Wall & Devor, 1981). Similarly the size of the volleys ascending the cord in axons from cord cells remains unaffected.3. If a peripheral nerve is cut and tested after 7-14 days, it produces a markedly decreased p.a.d. on itself and on its neighbours.4. If a nerve is crushed rather than cut, it produces a normal p.a.d. on itself and its neighbours after 7-14 days.5. In animals treated neonatally with capsaicin, there is a severe loss of unmyelinated afferents. Testing the effect of an orthodromic volley in myelinated afferents on the excitability of myelinated afferent central terminals shows that there is a strongly decreased p.a.d. in these animals.6. It is concluded that primary afferent depolarization is sensitive to peripheral nerve lesions and that it may be particularly dependent on the integrity of the unmyelinated afferents in spite of the fact that p.a.d. is measured as a phenomenon of myelinated afferents acting on myelinated afferents.

Action Potentials↗
PubMed1988

Neuroendocrine differentiation in the glandular peripheral nerve sheath tumor. Pathologic distinction from the biphasic synovial sarcoma with glands.

We studied eight glandular peripheral nerve sheath tumors and seven biphasic synovial sarcomas with glands with the objectives of (a) characterizing the nerve sheath tumors, especially with respect to a possible neuroendocrine differentiation, and (b) identifying features that could be used to distinguish between the two lesions. In a mainly immunohistochemical study, neuroendocrine differentiation of glandular cells was observed in five of eight (62.5%) nerve sheath tumors. The neuroendocrine cell markers found included chromogranin (five of eight cases), serotonin (four of seven cases), pancreatic polypeptide (two of five cases), and gastrin (two of six cases). These findings--together with histological, histochemical, and ultrastructural observations made in this and in other studies--point to a foregut type of intestinal differentiation for the glands in a majority of glandular peripheral nerve sheath tumors. Specific histological and immunohistochemical differences between the nerve sheath tumors and the synovial sarcomas were identified. The main histological differences were a sharp distinction between the spindle and glandular cells of the former but not the latter lesion, and the presence of goblet-type cells only in the glandular peripheral nerve sheath tumors. Major immunohistochemical differences included neuroendocrine differentiation and reactivity for S-100 protein and CEA (seen only or mainly in the nerve sheath tumors), and the reactivity of spindle cells of only the biphasic synovial sarcomas for epithelial membrane antigen.

Biomarkers, Tumor↗