Protocol for Endoscopic Versus Open Cubital tunnel release (EVOCU): an open randomized controlled trial : EVOCU trial: Endoscopic Versus Open Cubital tunnel release.

Background: Cubital tunnel syndrome is the second most common entrapment neuropathy of the upper extremity. Surgical decompression of the ulnar nerve aims to improve complaints and prevent permanent damage to the nerve. Open and endoscopic release of the cubital tunnel are both used in common practice, but none has proven to be superior. This study assesses patient reported outcome and experience measures (PROMs and PREMs respectively), in addition to objective outcomes of both techniques.

Methods: A prospective single-center open randomized non-inferiority trial will take place at the Plastic Surgery Department in the Jeroen Bosch Hospital, the Netherlands. 160 patients with cubital tunnel syndrome will be included. Patients are allocated to endoscopic or open cubital tunnel release by randomization. The surgeon and patients are not blinded for treatment allocation. The follow-up time will take 18 months.

Discussion: Currently, the choice for one of the methods is based on surgeon's preferences and degree of familiarity with a particular technique. It is assumed that the open technique is easier, faster and cheaper. The endoscopic release, however, has better exposure of the nerve and reduces the chance of damaging the nerve and might decrease scar discomfort. PROMs and PREMs have proven potential to improve the quality of care. Better health care experiences are associated with better clinical outcome in self-reported post-surgical questionnaires. Combining subjective measures with objective outcomes, efficacy, patient treatment experience and safety profile could help differentiating between open and endoscopic cubital tunnel release. This could aid clinicians in evidence based choices towards the best surgical approach in patients with cubital tunnel syndrome.

Trial Registration: This study is registered prospectively with the Dutch Trial Registration under NL9556. Universal Trial Number (WHO-UTN) U1111-1267-3059. Registration date 26-06-2021. The URL: https://www.trialregister.nl/trial/9556.