Carpal tunnel surgery

Indication of the site of the problem in carpal tunnel syndrome.

Carpal tunnel surgery, also called carpal tunnel release (CTR) and carpal tunnel decompression surgery, is a surgery in which the transverse carpal ligament is divided. It is a treatment for carpal tunnel syndrome and recommended when there is static (constant, not just intermittent) numbness, muscle weakness, or atrophy, and when night-splinting no longer controls intermittent symptoms of pain in the carpal tunnel.^[1] In general, milder cases can be controlled for months to years, but severe cases are unrelenting symptomatically and are likely to result in surgical treatment.^[2]

Medical uses

The procedure is used as a treatment to carpal tunnel syndrome and is intended to provide relief.

Technique

Scars from carpal tunnel release surgery. Two different techniques were used. The left scar is 6 weeks old, the right scar is 2 weeks old. Also note the muscular atrophy of the thenar eminence in the left hand, a common sign of advanced CTS.

The goal of any carpal tunnel release surgery is to divide the transverse carpal ligament and the distal aspect of the volar ante brachial fascia, thereby decompressing the median nerve and providing relief.^[3] The transverse carpal ligament is a wide ligament that runs across the hand, from the scaphoid bone to the hamate bone and pisiform. It forms the roof of the carpal tunnel, and when the surgeon cuts across it (i.e., in a line with the ring finger) it no longer presses down on the nerve inside, relieving the pressure.^[4]

The two major types of surgery are open carpal tunnel release and endoscopic carpal tunnel release. Most surgeons historically have performed the open procedure, widely considered to be the gold standard. However, since the 1990s, a growing number of surgeons now offer endoscopic carpal tunnel release.^[5] Existing research does not show significant differences in outcomes of one kind of surgery versus the other, so patients can choose a surgeon they like and the surgeon also will practice the technique they like.^[6]

Historically, carpal tunnel release was performed under general anaesthesia with a tourniquet, however the worldwide trend is now for 'wide awake hand surgery': with no tourniquet, no general or regional anaesthesia and no sedation; which also enables carpal tunnel release to be performed under local anaesthesia as a one stop procedure.^[7]

After carpal tunnel surgery, the long term use of a splint on the wrist should not be used for relief.^[8] Splints do not improve grip strength, lateral pinch strength, or bowstringing.^[8] While splints may protect people working with their hands, using a splint does not change complication rates or patient satisfaction.^[8] Using splints can cause problems including adhesion and lack of flexibility.^[8]

Carpal tunnel surgery is usually performed by a hand surgeon, orthopaedic surgeon, or plastic surgeon. Some neurosurgeons and general surgeons also perform the procedure.

Open surgery

The traditional open carpal tunnel surgery.

Open surgery involves an incision on the palm about an inch or two in length. Through this incision, the skin and subcutaneous tissue is divided, followed by the palmar fascia, and ultimately the transverse carpal ligament.^[9][10]

The open release technique has been compared to other treatments.^[11]

Endoscopic carpal tunnel release

Endoscopic techniques for carpal tunnel release involve one or two smaller incisions (less than half inch each) through which instrumentation is introduced including a synovial elevator, probes, knives, and an endoscope used to visualize the underside of the transverse carpal ligament.^[12] The endoscopic methods do not divide the subcutaneous tissues or the palmar fascia to the same degree as the open method does.^[13] Many studies have been done to determine whether perceived benefits of a limited endoscopic or arthroscopic release are significant.

Many surgeons have embraced limited incision methods. It is considered to be the procedure of choice for many of these surgeons with respect to idiopathic carpal tunnel syndrome. Supporting this are the results of some of the previously mentioned series that cite no difference in the rate of complications for either method of surgery. Thus, there has been broad support for either surgical procedure using a variety of devices or incisions.

Risks and complications

Carpal tunnel syndrome cannot be cured, but surgery to alleviate symptoms can be successful. The success rate of surgery to relieve symptoms depends on the definition of “success” and the metrics applied. For example, with respect to alleviation of symptoms, up to 90% success is reported. Yet with respect to patient satisfaction, approximately 50% is reported. The rate at which patients return to their former employer also is less than 90%. Yet approximately 25% of those patients are re-tasked to another duty in order to minimize further stress on their hands.^[14][15][16] In general, endoscopic techniques are as effective as traditional open carpal surgeries,^[17][18] though the faster recovery time typically noted in endoscopic procedures is felt by some to possibly be offset by higher complication rates.^[19][20] Success is greatest in patients with the most typical symptoms. The most common cause of failure is incorrect diagnosis, and it should be noted that this surgery will only mitigate carpal tunnel syndrome, and will not relieve symptoms with alternative causes. Recurrence is rare, and apparent recurrence usually results from a misdiagnosis of another problem. Complications can occur, but serious ones are infrequent to rare.

Recovery

In these surgeries, the flexor retinaculum is either simply severed or lengthened. When surgery is done to divide the flexor retinaculum (which is by far the more common procedure), scar tissue will eventually fill the gap left by surgery. The intent is that this will lengthen the flexor retinaculum enough to accommodate inflamed or damaged tendons and reduce the effects of compression on the median nerve

Research

Balloon carpal tunnelplasty is an experimental technique that uses a minimally invasive balloon catheter director to access the carpal tunnel. As with a traditional tissue elevator/expander, balloon carpal tunnelplasty elevates the carpal ligament, increasing the space in the carpal tunnel. As an experiment it has been described but there are no peer reviewed series available in the current hand surgical literature that review or comment upon the procedure. The technique is performed through a one-centimeter incision at the distal wrist crease. It is monitored and expansion is confirmed by direct or endoscopic visualization. The technique's secondary goals are to avoid to incision in the palm of the hand, to avoid cutting of the transverse carpal ligament, and to maintain the biomechanics of the hand.^[21]

References