Clinical, Electrophysiological, and Intraoperative Analysis and Postoperative Success of Revision Surgery for Persistent and Recurrent Carpal Tunnel Syndrome.

Background: This paper reviews the signs and symptoms of recurrent or persistent carpal tunnel syndrome and examines some of the causes of failed primary carpal tunnel release. Methods: A retrospective review of the surgical findings and outcomes of 29 consecutive patients who underwent 30 revision carpal tunnel operations was performed. Patient outcomes were recorded at a minimum of 1 year postoperatively. Results: Thirty hands in 29 consecutive patients underwent a second operation by a single surgeon. The average time interval from the first carpal tunnel release to the revision surgery was 5.7 years. Twenty-three patients experienced recurrent symptoms, and 7 had persistent symptoms. On preoperative examination, 77% demonstrated abductor pollicis brevis muscle weakness, 67% demonstrated a positive Phalen sign, and 63% demonstrated ring finger "sensory splitting." Incomplete release of the transverse carpal ligament and circumferential fibrosis were the most common intraoperative findings, totaling 20 cases each; intact antebrachial fascia (8 cases), volar subluxation of the median nerve (5 cases), compression of the median nerve by palmaris longus (4 cases), flexor tenosynovitis (4 cases), and aberrant anatomy (1 case) were also observed. Nine patients (34%) had complete resolution of symptoms after the revision carpal tunnel release. Fifteen patients (58%) had improvement in symptoms, and 2 patients did not report improvement. Conclusions: We have found the Phalen sign, comparison of the strength of the abductor pollicis brevis muscle, and subjective "splitting" of the ring finger sensation to be the most helpful findings in establishing the diagnosis. Persistent carpal tunnel syndrome is almost always secondary to incomplete division of the transverse carpal ligament.