gms | German Medical Science

Objectives/Interrogation: Endoscopic release of the median nerve according to Agee's original technique is limited to section of the flexor retinaculum without endocanalar exploration. We present a video of the modified Agee technique the purpose of which is to explore the carpal tunnel, including its contents and walls.

Methods: The procedure is performed under locoregional anesthesia with a tourniquet at the root of the arm. As soon as the endoscope is introduced into the carpal tunnel, the median nerve is located and section of the retinaculum is only performed afterwards. Once the retinaculum has been divided, exploration becomes easier. By longitudinal rotational movements of the endoscope we may visualize the following anatomical elements: the retinaculum margins confirming its complete section, the median nerve and its motor branch on the radial side, the long flexor of the thumb in its sheath outside, the flexor tendons of the 4th and 5th fingers with their lumbrical muscles on the ulnar side, the uncus of the hamatum and finally, behind the flexor tendons, the anterior capsulo-ligamentous parts of the carpus.

Results and Conclusions: On a continuous series of 100 carpal tunnels, the median nerve was always visualized before section of the retinaculum and the motor branch was visualized 82 times. Release of the motor branch was performed under endoscopy in 27 cases who presented thenar atrophy or a compressive anatomical element. In most of these cases, endocanalar vision associated with passive flexion/extension movements of the first metacarpal, revealed shearing of the motor branch due to fibrous reinforcement of the flexor fascia, this arch was sectioned. The long flexor of the thumb was individualized 87 times, the flexors of the 4th and 5th fingers with the lumbrical muscles 68 times. In 18 cases we found degenerative tendon lesions with a rough hamate. The anterior part of the carpus was visualized by passing the endoscope under the flexor tendons. A synovial cyst was found in one case.

This film shows that the endoscopic technique offers endocanalar anatomical vision with better quality than the classical open technique. It proves that complementary procedures, such as neurolysis of the median nerve and its motor branch, associated with section of the retinaculum are possible by endoscopy. This experience has led us to believe that, just as with wrist arthroscopy for the carpus, endoscopy will become a standard means of exploring the carpal tunnel.