Interfascicular neurolysis in chronic ulnar nerve lesions at the elbow: an electrophysiological study

Intraoperative electrophysiological studies to predict the efficacy of neurolysis after nerve injury-experiment in rats

Compound muscle action potentials (CMAPs) can be used to analyze injury and recovery of nerve. This standardized study evaluates the value of CMAP analysis in predicting the long-term efficacy of neurolysis. CMAP amplitude is also used to determine the optimal extent of neurolysis. The left peroneal nerves of 30 rats were crushed. CMAPs were recorded for both crushed (left) and control (right) nerves. Fifteen rats underwent neurolysis 3 months post crush injury; the remaining 15 were sham controls and did not undergo neurolysis. CMAP measurements were taken after: (1) release of the nerve from the fascia, (2) opening the epineurium, and (3) opening the perineurium. At 3 months post crush injury, opening the epineurium resulted in a statistically significant increase in CMAP. CMAP increase with perineurial neurolysis was greater than with fascial release of the nerve but was not statistically different from that of epineurial release. At 5 months post crush injury, recovery of crushed nerves that underwent neurolysis was 90% and significantly less at 70.5% in rats not treated with neurolysis, according to CMAP analysis. Two conclusions can be made from this study. First, intraoperative neurophysiologic studies can monitor the immediate results of neurolysis and predict long-term results in the injured nerve. Second, epineurotomy is important in neurolysis, improves the function of the nerve, less invasive, and a slightly more effective technique than perineurotomy.

Comparison of partial excision with simple section of the transverse carpal ligament in the treatment of carpal tunnel syndrome

In the surgical treatment of carpal tunnel syndrome, debate has commonly focused on whether decompression should be performed by open or blind techniques. Contrarily, the goal of the present study was to determine whether instead of simple section, partial excision of the transverse carpal ligament has contributed to better results. Because complete healing of the transverse carpal ligament observed during reoperations has been reported elsewhere, the charts of 75 carpal tunnel syndrome patients who had been treated with open technique at Dokuz Eylül University were reviewed. Statistical analysis was performed using the Fisher's exact test and Student's t test when appropriate. Thirty-five patients had been treated with simple section of the transverse carpal ligament, whereas 40 had been treated with partial excision. Internal neurolysis was also performed in 19 of the patients, 11 of whom were treated with partial excision. The average follow-up time was 3.8 years. The comparisons regarding the overall operative outcomes did not show any significant difference between the two different techniques of releasing the transverse carpal ligament. In patients treated without neurolysis, results of partial excision of the transverse carpal ligament improved when compared with those of simple section, but this superiority was not statistically significant. There seemed to be statistically higher reoperation rates and worse outcomes after neurolysis (p < 0.05). Reoperation was required in eight patients (11 percent). Five of the patients who underwent reoperation had initially been treated with partial excision and neurolysis, whereas two had been treated with simple section and neurolysis. Another patient who had undergone reoperation had initially undergone only simple section. The mean time to return to work or daily activities did not differ between the types of applied technique for releasing the transverse carpal ligament. However, neurolysis lengthened these periods significantly when performed (p < 0.05). In the present study, partial excision of the transverse carpal ligament without adding neurolysis offered relatively better results than simple section. Verification of this finding endoscopically, if applicable, may improve the success rate of surgical therapy in patients with carpal tunnel syndrome.

Entrapment neuropathy at the cubital tunnel: simple decompression is the method of choice

We present a retrospective study of 41 patients treated by simple decompression for ulnar neuropathy. Pre- and postoperatively, patients were evaluated clinically and electrophysiologically. The median follow-up was 2 years (minimum: 0.5 years, maximum: 5.1 years). The leading pre-operative sign was motor loss in the ulnar distribution (36 patients = 89%) with consecutive atrophy of ulnar innervated muscles (30 patients = 75%). The secondary complaint was sensory impairment in 59% of all cases, less frequently patients presented with pain or paraesthesia. In the majority of cases the aetiology remained unknown (27 patients = 65%). When aetiology was known, previous trauma to the elbow was reported most frequently (9 patients = 22%). Motor nerve conduction velocity (mNCV), compared to the contralateral, non-involved arm, was lower at least for 10 m/s. In cases with atrophy of the ulnar innervated muscles the difference was greater than 15 m/s. In 89%, postoperative results were good or even very good. In 8% (3 patients) no improvement was observed. Worsening due to surgery did not occur. We could demonstrate a significant increase in postoperative mNCV of 7.95 m/s in all patients (p < 0.05). There is still disagreement as to the correct surgical treatment of this disorder. We favour simple decompression (SD) as the appropriate operative technique for cubital tunnel syndrome.

Intraoperative electroneurography: management of ulnar neuropathy at the elbow

At the elbow the ulnar nerve may be compressed either in the retrocondylar groove or at the cubital tunnel. Optimal surgical therapy should be directed at the specific site of involvement. Intraoperative electroneurography performed in conjunction with 19 ulnar nerve explorations helped localize the precise site of compression. Of the primary procedures, abnormality was at the retrocondylar groove in 9, cubital tunnel in 4, both locations in 3, and at an unusual distal point in 1; 12 anterior subcutaneous transpositions, 4 cubital tunnel releases, and 1 distal decompression resulted. Intraoperative studies helped identify residual compression in two patients undergoing reexploration. Although routine electrodiagnosis may localize an ulnar neuropathy to the elbow, reliably separating retrocondylar from cubital tunnel compression is more difficult. Preoperatively, percutaneous serial short increment studies were more accurate than simple "inching" in predicting the site of compression.

Clinical and electrophysiological recovery from peroneal palsy

Clinical examination, electromyography and conduction studies in motor and sensory fibres were performed in 14 patients with peroneal palsy of compressive or spontaneous origin. After a period of from 5 months - 3 years, the clinical and electrophysiological examinations were repeated. The rate of recovery was not uniformly good, as only 6 of 14 patients had a complete clinical recovery. Most patients had an incomplete electrophysiological recovery which only partly corresponded to the clinical findings. Electromyography and conduction studies in sensory and motor fibres were found to be of value in predicting the outcome of the peroneal palsy.

Ulnar nerve entrapment at the elbow. Tailoring the treatment to the cause

Ulnar nerve entrapment at the elbow is a common cause of arm and hand pain, paresthesias, and weakness. Its characteristics and the appropriate diagnostic tests should be known to all primary care physicians. An understanding of the surgical treatment of this common disorder is helpful in providing informed medical care.

Sensitivity and localizing significance of motor and sensory electroneurographic parameters in the diagnosis of ulnar nerve lesions at the elbow. A reappraisal

A total of 103 patients (40 with pure sensory disturbances, 63 with sensory and motor deficits) with ulnar nerve lesions at the elbow were examined neurophysiologically. The measurement of motor conduction velocity across the cubital tunnel alone did not completely localize the lesion. The latency to an ulnar-innervated flexor muscle was of outstanding importance. The measurement of amplitudes was only rarely of localizing significance. The results of sensory recording proved to be important in patients with pure sensory disturbances. In cases with additional motor deficits, sensory recordings were too often abnormal in all segments of the ulnar nerve to be of substantial localizing value.

Conduction block in compression neuropathy: recognition and quantification

Previous reports of conduction block in compression neuropathy have used the amplitude difference of the compound muscle action potential (CMAP) comparing proximal with distal stimulation. The present study was undertaken to determine if area reduction of the proximal CMAP provides diagnostic information that is not included in amplitude reduction, particularly in distinguishing conduction block from temporal dispersion. Digitized, integrated area measurements were compared with amplitude and, as a convenient estimate of area, the calculated M-index (1/2 duration X amplitude). Amplitude reduction did not reliably distinguish conduction block from temporal dispersion in compression neuropathy. Both in the investigation of conduction block and in the management of compression neuropathy, integrated area measurement allows for the more accurate identification and quantification of conduction--a usually reversible cause for weakness in compression neuropathy.

Acute vs. chronic compressive neuropathy

Studies of the management of acute and chronic compressive peripheral neuropathies have not kept pace with advances in our understanding of the pathophysiology of these disorders. In this review, the pathophysiological differences between acute and chronic compressive neuropathy are reviewed from experimental models as well as from clinical examples in humans. It is concluded that surgical intervention is unlikely to alter significantly the course of recovery in acute compressive neuropathies. Similarly, in chronic compressive neuropathies without progressive weakness, conservative treatment is indicated because of the high incidence of spontaneous improvement. However, in patients with progressive weakness, especially in conjunction with electrophysiological evidence of partial denervation or conduction block (but not simply slowing of nerve conduction), surgical treatment is recommended.

Polyneuropathy in nonmalignant IgM plasma cell dyscrasia: a morphological study

Six patients had peripheral neuropathy and nonmalignant IgM plasma cell dyscrasia. In two of them, immunological studies indicated that the monoclonal immunoglobulin reacted with myelin-associated glycoprotein, a constituent of peripheral nerve myelin. Sural nerve biopsy specimens from both patients showed morphological signs of primary damage to the myelin sheath. In the other four patients, two of whom had a monoclonal IgMK reactive with chondroitin sulfate C, the axon rather than the myelin sheath was considered the chief site of nerve injury. The morphological findings suggest that the pathogenesis of peripheral neuropathies in IgM plasma cell dyscrasia is heterogeneous. Moreover, the observations are consistent with a pathogenic interaction of the IgM paraprotein with autoantigens in peripheral nerve in some instances.

Ulnar neuropathy at the elbow treated with decompression. A clinical and electrophysiological investigation

Forty-four patients with ulnar neuropathy confined to the elbow region were operated with simple decompression. The operation was usually performed more than six months after the debut of symptoms. At follow-up earliest six months postoperatively 89% of the patients had improved and 39% recovered completely. An improvement in EMG activity and/or nerve conduction velocity was seen in 89% of the patients tested pre- and postoperatively. The validity of nerve compression, epineurial fibrosis and other factors of possible prognostic significance such as age, duration of symptoms and electrophysiological findings are discussed. Since the results of simple decompression of the ulnar nerve were similar to those obtained in a previous study of transposition, the former method is recommended as the standard procedure.