Revision surgery for refractory cubital tunnel syndrome: A systematic review

Background: Indications for revision surgery are unclear in refractory cubital tunnel syndrome patients, and the optimal surgical method has not been determined. The systematic review evaluates the evidence of functional outcome for revision surgery in refractory cubital tunnel syndrome patients. Hypothesis: We hypothesize that functional outcome of revision surgery in refractory cubital tunnel syndrome will be favorable. Methods: We searched PubMed, Ovid/MEDLINE, Cochrane, Google Scholar, and EMBASE databases using the keywords “cubital tunnel syndrome” or “recurrent cubital tunnel syndrome” and “revision surgery” according to the MeSH index for English-language studies. We performed a systematic review using PRISMA guidelines. The review was registered in PROSPERO (CRD42018096622). Results: Based on the Oxford Centre for Evidence-Based Medicine criteria, one level 3b study and nine level 4 studies were identified, including 195 elbows of 192 patients aged 15–75 years. The remission period for recurrent cubital tunnel syndrome was 6–21 months, and the follow-up period was 6–113 months. Transposition surgery was the primary surgery in 99 (51%) of 178 elbows. The most common intraoperative finding at revision surgery was perineural scarring (79%), with the most frequent entrapment site being the medial intermuscular septum (33%). The most common revision surgery was submuscular transposition of the ulnar nerve (75%). Most studies reported favorable outcomes, although outcomes varied widely among studies. Conclusion: This is the first study to summarize the functional outcomes of revision surgery for refractory cubital tunnel syndrome which showed to be favorable. Functional outcomes were averagely reported and varied widely. A consensus regarding the functional outcomes parameter after surgery for cubital tunnel syndrome is urgently needed. Level of evidence: III, systematic review.