Evolving concepts of median nerve decompression in the carpal tunnel

Carpal tunnel syndrome is the most common and best known of the compression neuropathies in the upper extremity. The authors review their clinical experiences in the diagnosis and management of this entity and survey the extensive literature on the subject. An operative approach for decompression of the median nerve in the carpal canal is described that has proved to be most efficacious and safe.     

Pedicled fat flap coverage of the median nerve after failed carpal tunnel decompression

We reviewed 14 patients treated with either an ulnar or a hypothenar fat flap for recurrent carpal tunnel syndrome and scar tenderness. Nine patients were satisfied and there were few complications. One patient had delayed skin healing and another developed a hypertrophic scar.     

Intraoperative electroneurography during median nerve decompression in carpal tunnel syndrome

Summary In 17 patients with the diagnosis of carpal tunnel syndrome, orthodromic sensory nerve conduction measurements during ligament division and internal neurolysis were performed without the use of a pneumatic tourniquet. While ligament division led to an increase in conduction velocity (p < 0.05; median increase 0.7 m/s), it did not result in a significant change of the amplitude. During internal neurolysis, an increase of the sensory nerve potential (p<0.01; median increase 0.9 V) and no significant change in conduction velocity were observed. We conclude that internal neurolysis does not cause a disruption of nerve function during the operation.     

Evaluation of sensory function after median nerve decompression in carpal tunnel syndrome using the current perception threshold test

The recovery level for sensory function after carpal tunnel release for the treatment of idiopathic carpal tunnel syndrome (CTS) was assessed with the current perception threshold (CPT) test. Seventeen CTS patients (21 hands) were followed, and the CPTs at the index finger of each patient was measured preoperatively and at 1, 3, and 6 months postoperatively. After carpal tunnel release, there was significant recovery of CPT at all stimulation frequencies, indicating improvement of all sensory functions including sensations of temperature, pain, touch, and vibration.     

Contribution of magnetic resonance imaging for the diagnosis of median nerve lesion after endoscopic carpal tunnel release

Deterioration of pre-existing signs or appearance of a nerve deficit raise difficult problems during the complicated course following endoscopic carpal tunnel release. One possible explanation is transient aggravation of nerve compression by passage of the endoscopy material, but these signs may also be due to incomplete section of the flexor retinaculum or an iatrogenic nerve lesion. Each case raises the problem of surgical revision. The authors report three cases of open revision in which MRI allowed a very precise preoperative diagnosis of the lesions and all of the MR findings were confirmed during surgical revision. In the first case, MRI showed section of the most radial branches of the median nerve (collateral nerves of the thumb, index finger and radial collateral nerve of the middle finger). The proximal origin of the nerve of the 3rd web space, above the retinaculum, an anatomical variant, was also identified. Section of 2/3 of the nerve of the 3rd web space, proximal to the superficial palmar arch, was observed in the second case. Simple thickening of the nerve of the 3rd web space, without disruption after opening of the perineurium, was observed in the third case. MRI therefore appears to be an examination allowing early and precise definition of indications for surgical revision in this new iatrogenic disease.     

Time course and predictors of median nerve conduction after carpal tunnel release

PURPOSE: To identify predictors of outcome and of electrophysiologic recovery in patients with carpal tunnel syndrome (CTS) treated by endoscopic carpal tunnel release using a nerve conduction testing system (NC-Stat; NEUROMetrix, Inc, Waltham, MA). METHODS: Validity of the automated nerve conduction testing system was shown by comparing presurgical distal motor latencies (DMLs) against a reference obtained by referral to an electromyography laboratory. The DML was evaluated in 48 patients with CTS. Measurements were obtained within 1 hour of surgery and at 2 weeks, 6 weeks, 3 months, and 6 months after carpal tunnel release. Presurgical and postsurgical DMLs were then compared and correlated with variables and possible predictors of outcome including age, body mass index, gender, and presurgical DMLs. RESULTS: The automated nerve conduction testing system DMLs matched those of reference electromyography/nerve conduction study values with high correlation. Sensitivity of the automated nerve conduction testing system when compared with a standardized CTS case definition was 89%, with a specificity of 95%. A significant correlation was found between the DML before release and the DML 1 hour after release. Moreover, maximal postsurgical DML improvement was highly dependent on the presurgical DML, with no improvement shown for the <4-ms group, mild improvement for the 4-to-6-ms group, and maximal improvement in the >6-ms group. Among the clinical variables of age, gender, and body mass index only age was mildly predictive of postrelease DML changes at 6 months. No other correlations between clinical variables and postsurgical DMLs were significant. In addition the predictive value of age was lost when combined with the presurgical DML in a multivariate analysis. CONCLUSIONS: Postsurgical changes in the median nerve DML were highly dependent on the prerelease latency. The sensitivity and specificity of a nerve conduction monitoring system in detecting and aiding in the diagnosis of CTS is useful in the long-term management of patients with CTS and can aid in determining the level of improvement in median nerve function after endoscopic carpal tunnel release.     

Magnetic resonance imaging of the carpal tunnel

Eleven wrists in eight patients with carpal tunnel syndrome were investigated by electrophysiological studies and magnetic resonance imaging (M.R.I.). The operative findings in ten wrists correlated with the M.R.I. evidence of synovial disease, carpal tunnel stenosis and median nerve compression.     

Giant median nerve in bilateral carpal tunnel syndrome

We introduce a middle age healthy man with sequential bilateral carpal tunnel syndrome. At the surgery, we encountered a wide median nerve in both wrists. Although enlargement of median nerve in carpal tunnel has been well documented, 25 mm width of the nerve is a rare scene, underscoring that leaving the nerve under the unyielding pressure would lead to a fibrous atrophic median nerve.KEY WORDS: Blood-nerve barrier, carpal tunnel syndrome, compressive neuropathy, median nerve, neural edema     

Intraneural median nerve pressure in carpal tunnel syndrome

In order to determine whether endoscopic carpal tunnel release decompresses the median nerve, we measured the intraneural median nerve pressure pre- and postoperatively in 55 hands. The median nerve pressure was significantly reduced postoperatively.     

Sensory neural loop of the median nerve at the carpal tunnel

This article discusses a sensory neural loop on the radial aspect of the median nerve in the palm. The surgeon should be aware of this anomaly when the transverse carpal ligament is divided to approach the structures contained in the carpal canal.     

Giant cell arteritis of the median nerve simulating carpal tunnel syndrome

We present a distinctly rare case of giant cell arteritis involving the small artery of the median nerve with symptoms that may be confused with carpal tunnel syndrome. The excision of the involved arterial segment cures the patient of the local symptoms, but the administration of corticosteroids as soon as the diagnosis is established is very important for these patients with multiple arterial involvement.     

Carpal tunnel and median nerve volume changes after tunnel release in patients with the carpal tunnel syndrome: a magnetic resonance imaging (MRI) study

Purpose

Our aim was to study the dynamics of the post-surgical canal and nerve volumes and their relationships to objective [electromyoneurography (EMNG)] and subjective (pain) outcomes.

Methods

Forty-seven patients with carpal tunnel syndrome (CTS) (median age 52, range 23-75 years) with a prominent narrowing of the median nerve within the canal (observed during carpal tunnel release) were evaluated clinically using EMNG and magnetic resonance imagining (MRI) before and at 90 and 180 days post-surgery.

Results

Canal and nerve volumes increased, EMNG findings improved and pain resolved during the follow-up. Increase in tunnel volume was independently associated with increased nerve volume. A greater post-surgical nerve volume was independently associated with a more prominent resolution of pain, but not with the extent of EMNG improvement, whereas EMNG improvement was not associated with pain resolution.

Conclusions

Data confirm that MRI can detect even modest changes in the carpal tunnel and median nerve volume and that tunnel release results in tunnel and nerve-volume increases that are paralleled by EMNG and clinical improvements. Taken together, these observations suggest that MRI could be used to objectivise persistent post-surgical difficulties in CTS patients.Level of evidence 3 (follow-up study).

     

Measurement of carpal canal and median nerve pressure in patients with carpal tunnel syndrome

Carpal tunnel syndrome is a compression neuropathy wherein the median nerve is compressed inside of the carpal canal. Its diagnosis is made clinically, electrophysiologically, and sometimes by carpal canal pressure measurement. The objective of surgical management of this condition is the decompression of the median nerve. We usually measure carpal canal pressure preoperatively and postoperatively using a continuous infusion technique for diagnoses as well as for postoperative evaluation of decompression following our Universal Subcutaneous Endoscope system procedure. To evaluate whether our procedure effectively decompressed the median nerve, we measured intraneural pressure preoperatively and postoperatively in the resting position, with active power grip, and in the Okutsu test position. Correlation between the carpal canal pressure and intraneural median nerve pressure was statistically analyzed using the Kendall rank correlation coefficient (n = 157 hands). A significant correlation was present preoperatively in resting position and postoperatively with active power grip and in the Okutsu test position. Because of this correlation, we conclude that our endoscopic operative procedure effectively decompresses the median nerve and that simple carpal canal pressure measurement is sufficient to confirm diagnoses and to evaluate the status of postoperative decompression.     

Complete median nerve transection as a complication of carpal tunnel release with a carpal tunnel tome

A 48 year-old right-hand-dominant man presented to our institution with paresthesia and loss of feeling along the median nerve distribution of the right hand 1 week after undergoing minimally open carpal tunnel release with the Biomet Indiana Tome at another hospital. At surgery, transection of the median nerve was discovered and repaired. This is the first report of a complete median nerve transection using the revised carpal tunnel tome with a single-pass technique.