Strickland's hypothenar fat pad flap for revision surgery in carpal tunnel syndrome: Prospective study of 34 cases.

Several techniques are available for revision surgery of carpal tunnel syndrome (CTS) to preserve a gliding layer and protect the median nerve, including Strickland's pedicled hypothenar fat pad flap. The objective of this single-center, prospective study was to report the results of this flap after a minimum follow-up of two years. Between March 2006 and April 2014, 34 patients were enrolled (mean age 67 years) who had postoperative complications after the primary surgical release of CTS with nighttime paresthesia and/or neuropathic pain and abnormal electromyography findings. All patients were operated on using the same technique: neurolysis of the median nerve in the carpal tunnel with the nerve protected by a Strickland flap. The preoperative and postoperative evaluations consisted of questionnaires (paresthesia, neuropathic pain using the VAS and DN4 score, QuickDASH) and a clinical examination (grip strength, Weber two-point discrimination, atrophy of thenar muscles). Eighteen patients were reviewed in person and sixteen over the telephone. The outcomes were analyzed after at least 24 months' follow-up for all patients and 60 months for 13 patients. At 24 months postoperative, nighttime paresthesia was present in 3 of 34 patients and neuropathic pain in 2 of 24 patients. There was a significant reduction in pain on the VAS in all 34 patients (1.4 versus 6.4), the DN4 score (1.3 versus 5.7) and QuickDASH (60.7 versus 19.8). Of the 18 patients examined, grip strength improved from 72% to 86% of the opposite side (P<0.05), the mean static Weber was 6.4mm (versus 7.1mm preoperatively); nine patients had atrophy of the thenar muscles (versus eight preoperatively). The results observed at two years were maintained at five years' follow-up. This flap appears to improve the subjective neurological signs of CTS.