A new technique for endoscopic carpal tunnel decompression

Nerve entrapment: update

LEARNING OBJECTIVES

After reading this article, the participant should be able to: 1. Understand the pathophysiology of chronic nerve compression. 2. Describe the evaluation of a patient presenting with compression neuropathy. 3. Discuss the current controversies in the management of compression neuropathies. 4. Describe the treatment of common compression neuropathies, including carpal and cubital tunnel syndromes.

SUMMARY

Nerve entrapment syndromes are common in the general population, and are managed by a wide variety of medical and surgical specialists. A thorough understanding of the pathophysiology of nerve compression and appropriate clinical workup are critical in the overall management of these conditions. There remain several topics of controversy regarding the surgical management of nerve entrapment syndromes, including multiple points of nerve compression, carpal tunnel release under local anesthesia, open versus endoscopic decompression surgery, the "best" operation for primary cubital tunnel surgery, and revision decompression surgery. This article attempts to provide a concise summary of the advances in the basic and clinical science of peripheral nerve entrapment.

Endoscopic carpal tunnel release: a new single-portal device

Carpal tunnel syndrome is a common peripheral nerve disease, often requiring surgical intervention. After the first description of endoscopic carpal tunnel release 20 years ago, several endoscopic techniques have been described. The endoscopic procedure seems to have a better outcome in terms of time to return to work. A feared complication of endoscopic carpal tunnel release is injury to the median nerve or branches of the median nerve. We developed a new guiding cannula with raised borders, which will prevent accidental injury to the median nerve. A single-portal anterograde technique, to release the transverse carpal ligament, is described with the use of this new guiding device.

The surgery of peripheral nerves (including tumors)

Surgical pathology of the peripheral nervous system includes traumatic injury, entrapment syndromes, and tumors. The recent significant advances in the understanding of the pathophysiology and cellular biology of peripheral nerve degeneration and regeneration has yet to be translated into improved surgical techniques and better outcome after peripheral nerve injury. Decision making in peripheral nerve surgery continues to be a complex challenge, where the mechanism of injury, repeated clinical evaluation, neuroradiological and neurophysiological examination, and detailed knowledge of the peripheral nervous system response to injury are prerequisite to obtain the best possible outcome. Surgery continues to be the primary treatment modality for peripheral nerve tumors and advances in adjuvant oncological treatment has improved outcome after malignant peripheral nerve tumors. The present chapter provides background knowledge of surgical peripheral nerve disease and some general and practical guidance toward its clinical management.

CARPAL TUNNEL RELEASE WITH A LIMITED PALMAR INCISION: CLINICAL RESULTS AND PILLAR PAIN AT 18 MONTHS FOLLOW-UP

Limited open carpal tunnel release was performed in 58 hands (44 patients) using a single 1.5 cm palmar incision according to the technique described by Lee and Strickland.1The patients were assessed at regular intervals after surgery for hand functions and subjective symptoms, in particular pillar pain. There was rapid wound recovery with minimal post-operative pain and scarring, and return to functional activities within four weeks. At an average follow-up of 18 months (range 14–24 months), 91% of patients had complete or significant resolution of hand paraesthesia. No patient required further surgery. However, pillar pain was found in 48% of hands at four weeks, 21% at 12 weeks, 12% at six months, 9% at 12 months and 7% at the last follow-up. The significance of the incidence of pillar pain is discussed.

Endoscopic release of the carpal tunnel: a 2-portal-modified technique

Endoscopic carpal tunnel release has been popularized since 1989 when Okutsu described it for the first time. Several surgeons have followed his principles and described their own techniques. These were developed in an attempt to decrease the well-known complications related to the open technique. Single and 2-portal techniques have been described. Indications include patients with moderate Carpal tunnel syndrome (CTS) and failed conservative treatment. A modified Tsai 2-portal technique is used creating a "fixed surgical tunnel" for decompression and a custom made plastic tube is used to check the quality of release. A specific instrumentation is needed (A.M. Surgical, Smithtown, NY). Few complications are associated, finding it a reliable technique for the decompression of the carpal tunnel.

Mini open carpal tunnel release using Knifelight: evaluation of the safety and effectiveness of using a single wrist incision (cadaveric study)

This cadaveric study evaluates the margin of safety and technical efficacy of mini open carpal tunnel release performed using Knifelight (Stryker Instruments) through a transverse 1 cm wrist incision. A single investigator released 32 wrists in 17 cadavers. The wrists were then explored to assess the completeness of release and damage to vital structures including the superficial palmar arch, palmar cutaneous branch and recurrent branch of the median nerve. All the releases were complete and no injury to the median nerve and other structures were observed. The mean distance of the recurrent motor branch to the ligamentous divisions was 5.7 +/- 2.4 mm, superficial palmar arch was 8.7 +/- 3.1 mm and palmar cutaneous branch to the ligamentous division was 7.2 +/- 2.4 mm. The mean length of the transverse carpal ligament was 29.3 +/- 3.7 mm. Guyon's canal was preserved in all cases.

Results of 1245 endoscopic carpal tunnel decompressions

Between 1994 and 2000, the senior author performed 1245 endoscopic carpal tunnel decompressions. There were 291 bilateral cases. A telephone review was conducted of those patients who had not had an early excellent result, or conversion to an open procedure. Ninety-four per cent follow-up of patients in this group was achieved; 88% had an early excellent result with no subsequent problems. In 33 hands (3%) the carpal tunnel was opened, because of abnormal anatomy or poor view. A further 5% had a late excellent result. Seventeen hands (1%) have required subsequent open decompression, with adherence of the median nerve often found at revision surgery. Another 24 hands (2%) had a poor result. Fourteen hands (1%) had minor symptoms and 26 (2%) had another diagnosis of upper limb pathology. In contrast to other series, there was only one case of damage to an important structure - the radial digital nerve of the thumb.

Endoscopic carpal tunnel release

Endoscopic carpal tunnel release is not a procedure to be taken lightly. Like many surgical procedures, it is a demanding exercise that requires exacting knowledge of the anatomy of the hand, attention to detail, and the ability to manipulate three-dimensional objects while observing them in two dimensions on a video screen. In the hands of well trained surgeons, ECTR provides patients with a safe, predictable solution to their carpal tunnel sydrome that will allow them a rapid return to normal activities with minimal postoperative discomfort.

Multiple Entrapment Neuropathy in the Upper Extremity

Multiple entrapment neuropathy is compression of more than two nerves in the same extremity. In this case series, 169 patients (208 upper extremities) with this condition were identified, and 124 patients (138 upper extremities) had surgical decompression after an ineffective course of conservative treatment. There were 31 men and 93 women. Average age was 41 years (range 20-87 years). Follow-up averaged 23 months (range 12 to 60 months). Our rating system included patients' self-assessment of overall symptom improvement and return to activity and a physician assessment of strength (grip and pinch) and sensibility (recovery of two-point discrimination). A total of 92 patients (67%) achieved good to excellent results. The clinical features of multiple entrapment neuropathy in our series were presented with a variety of nerve compression syndromes and with a high incidence of regional musculotendinous syndromes. In our surgical treatment, we emphasise simultaneous release of all possible compression sites with a minimally invasive endoscopic approach to achieve better results.

Does endoscopic carpal tunnel release have a higher rate of complications than open carpal tunnel release? An analysis of published series

The purpose of this study was to evaluate the reported rate of complications after endoscopic carpal tunnel release by means of an analysis of 54 publications, reporting a total of 9516 endoscopic and 1203 open releases. Endoscopic release was comparable to open release in the rate of irreversible nerve damage (0.3% and 0.2% respectively) but case reports may indicate a small risk of unacceptable complications with endoscopy, such as transection of the median nerve. Reversible nerve problems were more common after endoscopic release. Tendon lesions were extremely rare (0.03%) and the rate of other complications (reflex sympathetic dystrophy, haematoma, wound problems, etc.) was about the same with endoscopic as with open release.

Ultrasonographically assisted carpal tunnel release

An operative technique of carpal tunnel release using intraoperative ultrasonography is described. In this technique, "safe line" is defined in the transverse carpal ligament and the adjacent deep forearm fascia midway between the ulnar margin of the median nerve and the radial margin of the ulnar artery. After ultrasonographic design of a 1.0 to 1.5-cm skin incision along the safe line at the distal carpal tunnel, the distal ligament is released under direct vision. Proximal release is performed along this line under ultrasonographic monitoring using a device that consists of a basket punch and an outer metal tube. In a prospective randomized study, the outcomes were compared for carpal tunnel release using either this technique in 50 hands of 50 patients or conventional open release in 53 hands of 53 patients. Follow-up assessment at 3, 6, 13, 26, 52, and 104 weeks showed no significant difference with respect to numbness and paresthesias, static two-point discrimination, findings on Semmes-Weinstein monofilament testing, findings on manual muscle testing of the abductor pollicis brevis, and electrophysiologic findings. The ultrasonographic-release group had better outcomes regarding pain, tenderness of the scar, and key-pinch strength at 3, 6, and 13 weeks, and grip strength at 3 and 6 weeks after surgery. The scar was more aesthetic in this group. There were no complications with either technique.

Total ulnar nerve transection during endoscopic carpal tunnel release

We report the case of a patient who suffered a complete laceration of the ulnar nerve during an endoscopic carpal tunnel release following Chow's two-portal extrabursal method. The possible mechanism of injury is discussed.