Endoscopic Carpal Tunnel Release
Reprinted from THE JOURNAL OF HAND SURGERY, St. Louis
Vol. 17, No 6, PP. 1009-1011, November, 1992
(Printed in the U.S.A.) (Copyright 1992 by Mosby-Year Book, Inc.)

We have performed 149 consecutive one-portal and 152 consecutive two-portal endoscopic carpal tunnel release operations. Average time to cessation of preoperative symptoms was 15 days in both the one-portal group and 17 days in the two-portal group. The complication rate in the one-portal group was 6%, and in the two-portal group it was 5%. In our opinion, the one-portal release technique is much more difficult and inherently more dangerous than the two-portal technique, and we recommend the latter for endoscopic carpal tunnel release.

(J. Hand Surg.1991;17A;1009-11)
Michael G. Brown, M.D.
Brent Keyser, M.D.
Eric S. Rothenberg, M.D. 
Houston, Texas

Division of tissue overlying the transverse carpal ligament (TCL) is inherent in the open carpal tunnel operation.^1,2 The healing of these superficial tissues may result in wound tenderness for some time after the procedure. This tenderness of the wound and later of the scar may inhibit application of palmar pressure and delay a return to maximum postoperative hand function. Complications of open carpal tunnel release have been described previously. ^3,4 

With the advent of new endoscopic instruments, it is now possible to release the ligament through one or two small incisions proximal and distal to the carpal tunnel, avoiding incision of the major portion of the overlying skin, fascia, muscle tissue, and possible fine nerve fibers.

Material and Methods
Our first group included 149 patients who had endoscopic carpal tunnel release with the original Agee Inside Job instrument before its redesign and reintroduction. The second group of 152 patients had a two portal release with a technique of our devising, which differs significantly from that of Chow^5,6 and other.^7,8. Before performing endoscopic carpal tunnel release on patients, the surgeon performed each procedure on twelve cadaver hands. This was followed by open dissections, which showed the complete division of the transverse carpal ligament and the absence of any injury to neurovascular structures.

In all patients carpal tunnel syndrome was diagnosed on the basis of history and physical examination with confirmatory nerve-conduction studies. In each case conservative treatment with splinting and anti-inflammatory medicines failed. All patients had normal x-ray views of the carpal tunnel. None of the patients were pregnant, and none had clinical evidence of thyroid disease. Three patients in the one-portal group had concomitant ulnar nerve entrapment in Guyon’s canal and were advised that endoscopic release might not solve their entire problem. Both open and closed procedures were carefully explained to each patient, and patients were allowed to choose between the procedures or to opt for continued non-operative therapy.

One-portal technique
For each of the techniques, patients were under general or intravenous regional block anesthesia and tourniquet control. The instrument (3M Agee Inside Job) was carefully checked, and marks were placed inside the channel to assist in proper positioning of the blade assembly. With the patient’s hand resting on a rolled towel, a 1.5-cm incision was made in the distal wrist crease ulnar to the palmaris longus. The anterior forearm fascia was exposed and an L-shaped incision was made in it. An elevator was used to push the synovium away from the under side of the TCL, and the "hamate finder" was used to confirm proper positioning. The instrument was then passed beneath the ligament until its distal edge was identified. The end of the channel was aligned with the distal edge of the ligament, a reference point on the ligament was noted relative to a channel mark, and the instrument.
THE JOURNAL OF HAND SURGERY

Results of 1236 Endoscopic Carpal Tunnel Release
Procedures Using the Brown Technique
Michael G. Brown, M.D., Eric S. Rothenberg, M.D.,
Brent Keyeser, M.D., Thomas T. Woloszyn, M.D.,
Any Wolford, R.N., M.S., C.N.S.

ABSTRACT
In a series of 1236 patients who underwent endoscopic carpal tunnel releases using the two portal Brown technique, the results were favorable in 98%, the failure rate was 2%, the instance of iatrogenic injury was O.O8% (one tendon injury), and the overall complication rate was O.97%. The patients had resolution of carpal tunnel syndrome in an average of 14 days and returned to work in an average of 15 days. Recurrence rate to date has been 2%, with the longest follow-up of 80 months. These results indicate that this is a safe and efficacious method of treatment for patients with carpal tunnel syndrome who require surgery.
 
INTRODUCTION
Surgical treatment of carpal tunnel syndrome was first described in 1947. An open approach to division of the transverse carpal ligament has been the mainstay of surgical treatment for this condition. With the exception of blindly-performed division of the transverse carpal ligament, open carpal tunnel release requires division of the overlying palmaris brevis muscle, palmar fascia, subcutaneous fat, possibly fibers of the thenar and hypothenar muscle, and skin. Division of these overlying structures has been cited as a cause for "pillar pain" and delay in the patient’s return to work and activities of daily living.

An endoscopic approach to the transverse carpal ligament was first described in 1989. In a double blind prospective randomized study comparing patients undergoing endoscopic carpal tunnel release with those undergoing open carpal tunnel release, the results were found to be superior in the endoscopic carpal tunnel release group with respect to postoperative strength, wound tenderness, and earlier return to work and participation in activities of daily living.  The superiority of endoscopic carpal tunnel release was supported further by a study demonstrating that a two-portal procedure is superior to a one-portal procedure. Considerable controversy has arisen regarding the ability to divide the transverse carpal ligament safely and completely using an endoscopic technique. Two cadaver studies using the technique described by Chow showed an unacceptably high incidence of incomplete ligament division and other technical complications. 

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