Endoscopic Carpal Tunnel Release: The Chow Dual-Portal Technique

Published on 11/04/2015 by admin

Filed under Orthopaedics

Last modified 11/04/2015

Print this page

rate 1 star rate 2 star rate 3 star rate 4 star rate 5 star
Your rating: none, Average: 0 (0 votes)

This article have been viewed 334 times

CHAPTER 31 Endoscopic Carpal Tunnel Release: The Chow Dual-Portal Technique

Rationale and Basic Science

James C. Y. Chow published his dual-portal technique in 19891 and reported his clinical results in 1990.2 The rationale for developing an endoscopic carpal tunnel release is similar to that used in the development of other endoscopic techniques such as laparoscopic cholecystectomy and arthroscopy. A minimal incision approach to carpal tunnel release leads to a decrease in postoperative pain and an earlier return to daily activities. The dual-portal system has the advantage of creating a fixed space in which to operate. The cannula is fixed at the proximal and distal portals. The cannula creates an operative field into which instruments can be easily moved (Figure 31.1).

Technique

Surgical technique

The dual-portal endoscopic carpal tunnel release, as described by Chow and modified by others, uses a proximal portal that is established 1 cm proximal to the wrist flexion crease just ulnar to the palmaris longus. The distal portal is established just distal to the distal edge of the transverse carpal ligament along the long axis of the ring finger. The volar antebrachial fascia is carefully entered, and a curved dissector is passed into the carpal tunnel—taking care to hug the hook of the hamate.

A “washboard” sensation is felt as the tip of the dissector passes over the ridges in the dorsal surface of the transverse carpal ligament (TCL). If this washboard sensation is not felt, the dissector is either palmar to the TCL or in Guyon’s canal. The distal edge of the transverse carpal ligament is able to be palpated using the curved dissector and the position of the distal edge of the transverse carpal ligament is marked on the overlying palmar skin (Figure 31.1).

The curved dissector is removed and the slotted cannula/obturator is placed into the carpal tunnel. The operator’s hand is placed on the palmar aspect of the hand between the thenar and hypothenar eminences and the cannula system is lifted (the lift test). The examiner’s palpating fingers should not be able to feel the cannula. If the cannula is palpable, it is either palmar to the TCL or in Guyon’s canal and must be removed and repositioned. Once the cannula is safely placed, taking care to stay close to the hook of the hamate and keeping the cannula system parallel to the long axis of the arm, the wrist and fingers are extended and the hand is placed on the hand holder. The tip of the cannula system is palpated just distal to the distal edge of the TCL. The cannula system is then passed through the distal portal while pushing the superficial palmar arch dorsally with the palmar arch depressor (Figure 31.2).

Buy Membership for Orthopaedics Category to continue reading. Learn more here