gms | German Medical Science

Objectives/Interrogation: Carpal tunnel release is associated with revision rates of 5-9%. Recurrent symptoms may be associated with perineurial scar formation and impaired nerve glide during functional movement of the wrist and flexors. An extended exposure of the median nerve with revision decompression and neurolysis is the recommended treatment, however the outcome of surgery is less favourable than for primary decompression surgery. We report a single institution experience of using porcine submucosa extracellular matrix (AxoGuard® AxoGen Inc., Alachua FL) in revision carpal tunnel surgery.

Methods: All patients undergoing revision carpal tunnel decompression and wrapping with an AxoGuard nerve protector between 2013 and 2018 were identified from a database at a regional hand and peripheral nerve injury service. Data capture included patient demographics, pre-and post-operative pain scores, sensation, Tinel's sign, DASH score and patient satisfaction assessed by DASH score were recorded.

Results: Thirteen patients with recurrent carpal tunnel compressive neuropathy were treated with revision release and AxoGuard nerve protector wrapping during the study period. The mean age at revision surgery was 42 years (range 24 to 79 years) and the mean follow up period was 42 months (range 4-36 months). The indication for application of the AxoGuard nerve protector was severe epineural scarring which was noted in all patients. Post-operative pain levels on a visual analogue scale improved from 8 to 3 (p<0.05) and subjective sensory improvement was from of 4 pre-operatively to 7 post-operatively using a 10/10 scale. All but one patient with neurofibromatosis reached the minimum clinically important difference in DASH score. Following revision surgery, absence of Tinel's sign was noted in all patients. In the current series there were no complications associated with the use of porcine submucosa extracellular matrix as a nerve wrap.

Conclusions: The application of a porcine submucosa extracellular matrix wrap as an adjunct to revision decompression and neurolysis of the median nerve is an effective treatment for patients with severe epineurial scar formation and adhesions. This pilot study has defined the treatment and assessment protocol. A large scale multi centre randomised controlled trial comparing simple decompression versus decompression and adjunctive wrapping in revision carpal tunnel surgery is required to evaluate the outcomes further.