Endoscopic Carpal Tunnel Release

Techniques, Controversies, and Comparison to Open Techniques

Jacques H. Hacquebord, MD; Jeffrey S. Chen, MD; Michael E. Rettig, MD


J Am Acad Orthop Surg. 2022;30(7):292-301. 

In This Article

Surgical Technique

Many modifications to ECTR technique have been made since its original description in 1987 by Okutsu et al,[8] whose technique consisted of placing both an endoscope and an instrument into a single volar incision. Two main techniques exist today—the two-portal technique and the single-portal technique. In reality, the exact steps to perform ECTR are often dictated by the configuration of the specific instrumentation to be used and are not the focus of this review. Cannula design, degrees of freedom, and blade orientation are examples of how individual systems can alter surgical technique. Specifics aside, each technique has several essential surgical steps, which will be reviewed below.

Two-portal Technique

The two-portal technique was first described in 1989 by Chow.[9] The first portal is made at the wrist flexion crease between the flexor carpi ulnaris and flexor carpi radialis tendons. The fascia is incised, and a trocar-cannula assembly is inserted into the carpal tunnel using the hook of the hamate as a guide (Figure 1). The wrist and fingers are then held in extension with a specialized device, and the assembly is advanced into the palm. The second portal is made in the palm over the tip of the trocar, and the endoscope is placed into the trocar at the proximal portal to visualize the undersurface of the transverse carpal ligament (TCL). A series of blades are then inserted into the distal portal to sequentially release the distal half of the ligament. Finally, the endoscope and blades are switched, and the proximal ligament is divided. The antebrachial fascia is then released through the proximal incision with tenotomy scissors. Although the original description by Chow used several specialized blades, modern systems frequently use one blade for a single pass through the TCL.

Figure 1.

Illustration showing correct placement of trocar through the carpal tunnel into the palm with the two-portal endoscopic technique. The trocar enters on the radial aspect of the hook of the hamate and exits on top of the superficial palmar arch (Reprinted from Arthroscopy, 5(1), Chow JC, Endoscopic release of the carpal ligament: A new technique for carpal tunnel syndrome, 19 to 24, 1989, with permission from Elsevier).

Single-portal Technique

Agee et al[10] introduced the contemporary single-portal technique in 1992, developed in concert with a new blade assembly device, which allowed blade deployment and visualization through a single window. A single incision is made at the wrist flexion crease in a similar fashion as previously mentioned. A distally based flap of antebrachial fascia is raised, and synovial tissue is cleared from the undersurface of the TCL followed by insertion of the blade assembly into the carpal tunnel (Figure 2, A). Once the ligament is properly visualized, the blade is deployed and the ligament is sequentially released in a retrograde fashion. The antebrachial fascia is then released with tenotomy scissors. Although the original description of Agee et al used a blade assembly with retrograde design, current systems offer both antegrade (Figure 2, B and C) and retrograde options.

Figure 2.

Intraoperative images demonstrating the single-portal endoscopic technique. A, Clinical photograph demonstrating proper placement of a single-portal endoscopic device with the assistant providing exposure. B, Endoscopic image with knife deployed releasing the transverse carpal ligament (TCL) in an antegrade fashion. The TCL can be identified by its transverse fibers. The distal margin can be identified by the fat pad visualized distally. C, Endoscopic image after TCL release has been completed. Radial and ulnar leaflets of the TCL are visualized, and complete release of the distal margin is confirmed. TCL = transverse carpal ligament