EVOCU Trial: Endoscopic Versus Open CUbital tunnel release

Background
Cubital tunnel syndrome is the second most common entrapment neuropathy of the upper extremity after carpal tunnel syndrome. For surgical decompression, two methods are being used in common practice: an open or an endoscopic release. There is ongoing debate as to what constitutes the superior surgical approach. So far, only objective outcomes have been studied and these studies have not been randomised. Moreover, these objective measures might not adequately reflect the succes of the surgical procedure. This study therefore aims to determine efficacy of open and endoscopic cubital tunnel release in terms of patient reported outcome measures, patient reported experience measures and complications.

Methods
This prospective single-center open randomised trial will include 160 patients with clinically objectified cubital tunnel syndrome and will take 18 months from baseline. Patients are randomised to receive cubital tunnel release using the open or endoscopic approach. The surgeon and patients are not blinded for treatment allocation. The trial will take place at the Plastic Surgery Department of the Jeroen Bosch Hospital, the Netherlands.

Discussion
Currently, the choice for one of the methods is based on surgeon’s preferences and degree of familiarity with a particular technique, which is mostly the open technique on the assumption that this is easier, faster and cheaper. The theoretical benefits of an endoscopic release include a less invasive surgical technique, reduced nerve complications and decreased scar discomfort. PROMs and PREMs have potential to improve the quality of services and that better health care experiences are associated with better clinical outcome in self-reported postsurgical 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.

We hypothesise that open and endoscopic cubital tunnel release have a different effectiveness in treating cubital tunnel syndrome in both primary and secondary outcomes. Since the RCTs performed were of moderate-quality and consists of a relatively low number of patients, the American Society for Surgery of the Hand (2018) states that research data on the optimal surgical treatment for cubital tunnel syndrome remains inconclusive. A more large-sample, high- quality RCT is needed to verify the outcomes.

- Before baseline - demographics, disease history, disease characteristics, physical examination, EMG
- Baseline (surgery) - PROMS (BCTQ and PRUNE), surgical characteristics
- 2 weeks - pain (VAS), complications
- 6 weeks (phone call) - pain (VAS), RTW, complications, Bishop
- 3 months - pain (VAS), RTW, complications, Bishop, PREM, two-point discrimination, PROMS (BCTQ and PRUNE)
- 12 months - pain (VAS), RTW, complications, Bishop, two-point discrimination, PROMS (BCTQ and PRUNE), POSAS
- 18 months (online) - pain (VAS), PROMS (BCTQ and PRUNE)

Open cubital tunnel release and endoscopic cubital tunnel release.