Endoscopic Carpal Tunnel Release (ECTR) refers to a method of performing carpal tunnel release surgery using an endoscope or an arthroscopic device.
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ECTR uses myriad blades to release the transverse carpal ligament (TCL) that overlies and compresses the median nerve within the carpal tunnel. It is this compression on the median nerve that leads to the characteristic 'pins and needles' paresthesia in the thumb, index, long and ring fingers. The primary benefit of endoscopic releases versus traditional open carpal tunnel release is often perceived to be the smaller incision size. ECTR incisions are commonly less than 1 cm (0.39 in) compared to a 2–4 in (51–100 mm) longitudinal incision with a traditional carpal tunnel release. However, the incision size is not the only factor that differentiates the two methods. The principle behind the endoscopic release is that the Palmar aponeurosis, a thick tough layer of tissue that lines the palm, is not divided with endoscopic methods. In addition, the endoscopic methods offer less dissection and interruption of tissue planes than the open methods. Thus, a more rapid recovery is generally touted with ECTR as the normal skin above the TCL is not incised. Surgery, either open or endoscopic is a way to treat Carpal Tunnel Syndrome.
The use of an endoscope to release the carpal tunnel was first described in 1989 by Okutsu et al.[1] Here a flexible clear plastic tube was used with a standard endoscope to identify the transverse carpal ligament and release it with a retrograde knife.
Many variations of the endoscopic or arthroscopic methods have been described, each with its own unique apparatus and surgical protocol.
The two more common and popular devices were referred to early on as the Chow device and the 3M Agee device. The Chow device is a two-portal device, while the 3M Agee endoscopic carpal tunnel release system is a single-portal device. The Chow device was produced by Dyonics and early papers documented its success. It was heralded by its corporate manufacturer as a breakthrough in carpal tunnel surgery. The Agee 3M device used a single, transverse incision in the area of the proximal wrist flexion crease. The Chow two-portal or two-incision device has had other manifestations, and the Agee device was bought by MicroAire Surgical Instruments. Both methods are still in use today.
Additional modifications in technique for a smaller or limited incision have been accompanied by many variations of knives, rasps and tubes through which these instruments and the imaging arthroscope or endoscope are passed. Despite the many manifestations of these devices they are all either a single or two portal system. Athrex, Brown-Instratek, Linvatek and other manufacturers modified the original one or two portal systems for endoscopic carpal tunnel release. Most of these methods utilize an endoscope to visualize the under surface of the transverse carpal ligament while others simply rely on instrumentation that allows for a smaller incision and instrumentation that aids in guiding the surgeon's modified blade or knife. Lastly, several years later a distal portal or single incision in the distal palm was advocated by a group from Louisville.
Many studies have been done to determine whether the perceived benefits of a limited endoscopic or arthroscopic release are truly significant. One prospective, randomized, multi-center study found no significant differences between the two groups with regard to the secondary quantitative outcome measurements. However, the open technique resulted in more tenderness of the scar than did the endoscopic method. A prospective randomized study using the MicroAire system was conducted in 2002 by Trumble and Diao et al and revealed that good clinical outcomes and patient satisfaction are achieved more quickly when the endoscopic method of carpal tunnel release is used. Their study concluded that single-portal Endoscopic carpal tunnel release surgery is a safe and effective method of treating carpal tunnel syndrome. There was no significant difference in the rate of complications or the cost of surgery between the two groups. However the open technique resulted in greater scar tenderness during the first three months after surgery as well as a longer time until the patients could return to work.[2]