Comparing endoscopic decompression of the ulnar nerve with open decompression in the surgical management of cubital tunnel syndrome

UNDER Study: Ulnar Nerve Decompression Endoscopic Randomisation Study. A prospective randomised controlled trial comparing endoscopic decompression of the ulnar nerve with open decompression in the surgical management of cubital tunnel syndrome

Status

Active, not recruiting

Phases

Unknown

Study type

Interventional

Source

ISRCTN

Registry ID

ISRCTN65991101

Enrollment

334

Registered

2024-02-28

Start date

2024-04-11

Completion date

Unknown

Last updated

2026-04-20

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Cubital tunnel syndrome Surgery

Interventions

Participants will be recruited into UNDER Study at treating hospitals and will do so at either the Cohort or RCT phase. Participants in the Cohort will receive only Endoscopic Decompression surgery fo

Eligibility

Sex/Gender

All

Age

18 Years to 80 Years

Inclusion criteria

Inclusion criteria: 1. Adult patients aged 18-80 years at the time of surgery 2. Clinical and neurophysiological diagnosis of cubital tunnel syndrome (CuTS) [moderate / severe CuTS with subjective or objective motor weakness] or persistent symptoms of CuTS after a 3-month period of activity modification for mild severity cases 3. Patients willing to be randomised to either Endoscopic Decompression or Open Decompression surgery for CuTS* *inclusion criteria for the RCT only

Exclusion criteria

Exclusion criteria: 1. Patients with a previous surgery for CuTS in the same limb 2. Pre-operative ulnar nerve subluxation at the elbow identified on clinical examination 3. Clinical diagnosis of CuTS with normal neurophysiology studies 4. Planned concomitant surgery in the same arm 5. Patients unable to provide consent 6. Patients unable to complete the follow up pathway including completing follow-up questionnaires

Design outcomes

Primary

Measure	Time frame
Phase 1: Surgeon Review CRF based on complications during and 6-weeks post-surgery, conversions to open decompression, and surgeon confidence from delivering the endoscopic decompression Phase 2: Patient-rated ulnar nerve evaluation (PRUNE) score at 3 months post-surgery	—

Secondary

Measure	Time frame
1. Determine the cost effectiveness of ED and OD for the surgical management of CuTS using a parallel economic evaluation: Length of procedures recorded on day of surgery 2. Complications at all visits 3. EuroQol EQ-5D-5L measured at baseline, 3 months, and 6 months post-surgery (plus additional 24-month follow-up for those that reach this timepoint within the open data collection window of the study), Within-trial estimate of cost-effectiveness over a 6-month time horizon. Decision-analytic modelling-based estimate of cost-effectiveness over a lifetime time horizon 3. To assess the complication profile and rate for ED and OD techniques in the surgical management of CuTS:: Complications data captured and classified using the Clavien-Dindo system on day of surgery, 6-weeks (Phase 1 only), 3-, 6-, and 24-months 4. To assess clinical recovery in terms of elbow range of motion, muscle strength and return to work following ED and OD: Elbow goniometry plus BMRC motor function at baseline and 3-months, and work status at 3-, 6-, and 24-months 5. To assess clinical recovery in terms of function, symptoms, and pain: Modified Wilson Krout Classification at 6-Weeks (Phase 1 only), and three months 6. To assess patient satisfaction with the surgical scar for the ED and OD surgery: POSAS V2.0 at 3-months 7. To understand the surgeon learning curve for the ED procedure (Phase 1 & 2): Surgeon Confidence on day of surgery (Phase 1 only), Complications at 6 weeks (Phase 1 only), complications, revision rates and functional outcomes at 3-, 6- and 24-months 8. To determine symptom recurrence at 6 months following ED and OD: PRUNE score and need for secondary intervention at 6-months	—

Measure

Time frame

1. Determine the cost effectiveness of ED and OD for the surgical management of CuTS using a parallel economic evaluation: Length of procedures recorded on day of surgery 2. Complications at all visits 3. EuroQol EQ-5D-5L measured at baseline, 3 months, and 6 months post-surgery (plus additional 24-month follow-up for those that reach this timepoint within the open data collection window of the study), Within-trial estimate of cost-effectiveness over a 6-month time horizon. Decision-analytic modelling-based estimate of cost-effectiveness over a lifetime time horizon 3. To assess the complication profile and rate for ED and OD techniques in the surgical management of CuTS:: Complications data captured and classified using the Clavien-Dindo system on day of surgery, 6-weeks (Phase 1 only), 3-, 6-, and 24-months 4. To assess clinical recovery in terms of elbow range of motion, muscle strength and return to work following ED and OD: Elbow goniometry plus BMRC motor function at baseline and 3-months, and work status at 3-, 6-, and 24-months 5. To assess clinical recovery in terms of function, symptoms, and pain: Modified Wilson Krout Classification at 6-Weeks (Phase 1 only), and three months 6. To assess patient satisfaction with the surgical scar for the ED and OD surgery: POSAS V2.0 at 3-months 7. To understand the surgeon learning curve for the ED procedure (Phase 1 & 2): Surgeon Confidence on day of surgery (Phase 1 only), Complications at 6 weeks (Phase 1 only), complications, revision rates and functional outcomes at 3-, 6- and 24-months 8. To determine symptom recurrence at 6 months following ED and OD: PRUNE score and need for secondary intervention at 6-months

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Countries

England, Northern Ireland, Scotland, United Kingdom, Wales

Contacts

Public ContactScott Parsons

understudy@ndorms.ox.ac.uk+44 1865 223489

Outcome results

None listed

Source: ISRCTN (via WHO ICTRP) · Data processed: Apr 23, 2026