Free muscle flap coverage as last resort for therapy-resistant neuropathic pain in the upper extremity: A long-term retrospective follow-up study.

Background: Persistent neuropathic pain severely impacts physical functioning and quality of life (QoL). However, optimal surgical management of persistent neuropathic pain remains unclear. Extensive neurolysis with subsequent free muscle flap coverage, a new surgical procedure for neuropathic pain in the upper extremity, can be performed as a final option to establish pain reduction.

Methods: All consecutive patients who received extensive microsurgical neurolysis with subsequent free muscle flap for persistent neuropathic pain in the upper extremity between 2007 and 2014 were identified. Patient-reported upper extremity function and QoL were assessed using three questionnaires (36-item short-form health survey (SF-36), the disabilities of the arm, shoulder, and head questionnaire, and the Michigan hand outcomes questionnaire).

Results: Fifteen patients were identified; 80% had neuropathic pain in the upper extremity due to nerve injury and a median of 3.0 previous surgeries (range 1-6). Sixty-seven percent developed some kind of complication, flap loss occurred in 22%, and all received a new free flap (one failed again). At last follow-up, pre- and postoperative visual analog scale (VAS) scores significantly differed (p = 0.002), and the median VAS at last follow-up was 1.5. Ten patients (67%) responded to the questionnaires after a median follow-up of 5.7 year (range 2.6-7.3 years). Patients on average reported poorer SF-36 "Physical Component Score" (PCS) and "Bodily Pain" compared to Dutch norms. Forty percent of patients reported still having always (very) severe pain. However, 64% had a postoperative decrease of at least 3.0 on VAS.

Conclusions: Extensive neurolysis with free muscle flap coverage for persistent neuropathic pain in the upper extremity showed a positive effect on pain reduction on short-term follow-up, and also at five-year follow-up. The impact of pain on functional outcomes remained. Nevertheless, 60% of the patients still experience sufficient pain reduction.