Bifid median nerve as a determinant of carpal tunnel syndrome recurrence after endoscopic procedures. A case report

A number of complications have been associated with endoscopic technique in treating carpal tunnel syndrome (CTS). We observed a female patient who had previously undergone endoscopic surgery for CTS. Shortly after surgery, this patient complained of pain, numbness and strength deficiency, as severe as it was before the operation. A new, open, surgical procedure was performed. During this second-look surgery, we found a bifid median nerve, which divided into two branches at the second third of the forearm, proximal to the flexor retinaculum. We strongly suggest a careful exploration of the median nerve in the carpal tunnel. Moreover, we believe that an extensive preoperative assessment of median nerve morphology and function is mandatory prior to endoscopic approach in treating CTS.     

Electromyographic evaluation after endoscopic carpal tunnel release in idiopathic carpal tunnel syndrome

The purpose of this study was to electromyographically evaluate results in patients with carpal tunnel syndrome (CTS) who underwent endoscopic carpal tunnel release (ECTR). The subjects were 26 patients with idiopathic CTS (37 hands) who were followed for at least 6 months after ECTR. To compare results informatively, hands were classified into four groups: those with normal distal motor latency (DML) and sensory conduction velocity (SCV) were classified as group A, those with normal DML and abnormal SCV as group B, those with an abnormal DML and normal SCV as group C, and those with abnormal DML and SCV as group D. All but one of the hands were classified as group D on the basis of preoperative electromyographic evaluation, while one was classified as group C. The mean preoperative obtainable DML and SCV values were 7.2 m and 27.3 m/s, respectively. Postoperatively, 12 hands were in group A, 8 hands in group B, 2 hands in group C, and 15 hands in group D. The mean DML and SCV values at final follow-up were 4.3 ms and 40.8 m/s, respectively. Of the 25 hands with muscle atrophy before surgery, 6 hands were in group A, 5 hands were in group B, 1 hand was in group C, and 13 hands were in group D at final follow-up. Thenar muscle atrophy and denervation potentials were present before surgery in 13 of the 15 hands classified as group D at the final follow-up. Received for publication on June 23, 1998; accepted on Oct. 30, 1998     

Bilateral palmaris profundus in association with bifid median nerve as a cause of failed carpal tunnel release

This is a case in which an anomalous tendon of the palmaris profundus was found running on the anterior surface of the median nerve, dividing the nerve into 2 branches at the wrist bilaterally. Excision of the tendon at the time of re-exploration of the carpal tunnel resulted in complete relief of carpal tunnel symptoms.     

Endoscopic carpal tunnel release for recurrent carpal tunnel syndrome after previous open release.

Recurrent carpal tunnel syndrome from various causes has been shown to occur in up to 19% of patients. Endoscopic carpal tunnel release has been used to decompress the median nerve in carpal tunnel syndrome for many years. However, endoscopic release for recurrent carpal tunnel syndrome after previous surgical release has not been reported. Nine hands in six patients had recurrent carpal tunnel syndrome five to 20 years after previous open carpal tunnel release. All the cases were successfully treated with endoscopic release.     

Ulnar subluxation of the median nerve following carpal tunnel release: a case report

Complications of carpal tunnel release, while infrequent, include incomplete release resulting in persistent symptoms or recurrence due to postoperative scarring, as well as iatrogenic damage to nerves and vessels. We present the case of a patient who underwent carpal tunnel release with resolution of symptoms in the immediate postoperative period. At one and a half years post release he started to experience numbness and tingling in a median nerve distribution triggered by repetitive ulnar to radial deviation of the wrist, with no symptoms at rest. Dynamic ultrasound showed a subluxation of the median nerve from one side of the palmaris longus tendon to the other. The patient's symptoms were triggered as the median nerve squeezed in between the palmaris longus and flexor digitorum superficialis tendons.     

Carpal tunnel syndrome caused by a fibrolipomatous hamartoma of the median nerve treated by endoscopic release of the carpal tunnel

Fibrolipomatous hamartoma has up to now been considered a rare anomaly that most commonly affects the median nerve. Its pathogenesis is controversial. The magnetic resonance (MR) appearance is pathognomonic and precludes the necessity for a diagnostic biopsy. Its reported incidence is likely to increase as a result of the increased use of MRI. There is no definitive treatment, although carpal tunnel syndrome caused by fibrolipomatous hamartoma has been noted to respond to open release of the carpal tunnel. We describe a case of carpal tunnel syndrome caused by fibrolipomatous hamartoma of the median nerve that responded to a two-port endoscopic technique of release. Provided that a safe, distinct surgical plane can be established between the median nerve and the flexor retinaculum, the two-port technique of endoscopic release of the carpal tunnel is both safe and effective.     

Outcomes of open and endoscopic carpal tunnel release: a meta-analysis

Background

Currently, there are two genres of surgical treatment of carpal tunnel syndrome, open versus endoscopic. The goal of our study is to analyze published data by comparing outcomes of surgical treatment for carpal tunnel syndrome and determine if one approach is superior to the other (open versus endoscopic).

Methods

A meta-analysis of retrospective series of Carpal tunnel release including >20 patients, with results measuring outcomes based on at least six of the following nine parameters (paresthesia relief, scar tenderness, two-point discrimination, thenar muscle weakness, Semmes–Weinstein/SW monofilament testing, return to work time, grip and pinch strength, and complications).

Results

Endoscopic carpal tunnel approach showed statistically superior outcomes in eight of the nine categories investigated. Only in the category of complications (mean occurrence of 1.2 % in the open release versus 2.2 % in the endoscopic release group) was the endoscopic group inferior.

Conclusion

This suggests that the endoscopic release is superior to the open release, particularly in experienced hands.     

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.     

腕管综合征内窥镜手术预防正中神经损伤的临床研究

目的 介绍腕管综合征内窥镜手术(endoscopic carpal tunnel release,ECTR)预防正中神经损伤并发症的方法.方法 利用彩色多普勒超声仪(B超)对37例74手患者术前进行检测.结果 71例正中神经走行在桡侧腕屈肌腱与掌长肌腱之间,3例走行在掌长肌腱与尺侧腕屈肌腱之间,并术中确认.结论 正中神经变异走行在掌长肌腱与尺侧腕屈肌腱之间是ECTR的禁忌证,B超能准确定位正中神经与掌长肌腱关系,避免内窥镜手术损伤正中神经,更具有简单、经济、方便可靠等优点.

Abstract：

Objective To introduce a method of preventing median never injury during endoscopic carpal tunnel release (ECTR). Methods Ultrasonography of both wrists was done to 37 patients of carpal tunnel syndrome who were going to undergo open release of the transverse carpal ligament. Structures in the carpal tunnel were visualized to guide surgical decision-making. Results Ultrasonography showed that median never lies between the tendon of flexor carpi radialis and palmaris longus in 71 patients and lies between the tendon of palmaris longus and flexor carpi ulnaris in 3 patients. These findings were confirmed during the surgeries. Conclusion It is a contraindication of ECTR if median never lies between palmaris longus and flexor carpi ulnaris. Ultrasonography can accurately reveal the relative position of median never to the palmaris longus tendon. Pre-operative ultrasonography of the wrist is a simple, inexpensive and convenient method to exclude these contraindications and thus prevent median never injuries in ECTR.     

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.     

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.     

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.     

Complications of endoscopic and open carpal tunnel release.

Separate questionnaires regarding surgically treated complications of endoscopic and open carpal tunnel release over a 5-year period were sent to members of the American Society for Surgery of the Hand to assess and compare major complications of the 2 procedures. Four hundred fifty-five major complications from endoscopic carpal tunnel release were treated by the 708 respondents. This included 100 median nerve lacerations, 88 ulnar nerve lacerations, 77 digital nerve lacerations, 121 vessel lacerations, and 69 tendon lacerations. There were 283 major complications from open carpal tunnel release treated by 616 respondents, including 147 median nerve lacerations, 29 ulnar nerve lacerations, 54 digital nerve lacerations, 34 vessel lacerations, and 19 tendon lacerations. Although this is a retrospective voluntary study with resultant methodologic flaws, the data support the conclusion that carpal tunnel release, be it endoscopic or open, is not a safe and simple procedure. Major, if not devastating, complications can and do occur with both procedures, of which surgeons should be ever cautious.     

Early recovery after endoscopic vs. short-incision open carpal tunnel release

Endoscopic carpal tunnel release has been claimed to offer improvement in recovery time and postoperative discomfort over open carpal tunnel release. Short-incision open carpal tunnel release has been claimed to offer recoveries comparable with endoscopic techniques. Patients receiving carpal tunnel surgery were randomized to short-incision open release or single-portal endoscopic release. Preoperative and postoperative evaluation included grip and pinch strength measurements and patient completion of a questionnaire regarding symptoms and function. Thirty-six operated hands completed evaluation, including 22 endoscopic and 14 open releases. Early grip and pinch strength after endoscopic carpal tunnel release were improved significantly over short-incision open release (p < 0.05). Subjective evaluation indicated a trend toward improved symptoms and function with endoscopic over short-incision open carpal tunnel release. Endoscopic carpal tunnel release provides faster recovery of strength than short-incision open carpal tunnel release and improves early postoperative comfort and function to a small degree.