Background Trials in occupational populations, such as surgeons, face feasibility challenges due to high workload, restricted availability, and clinical heterogeneity, which may compromise recruitment, adherence, and retention.

Objective To prespecify the feasibility framework and progression criteria for an internal pilot phase embedded within a pragmatic randomized controlled trial (RCT) comparing Mechanical Diagnosis and Therapy with generalized exercise in surgeons with chronic spinal pain.

Design Protocol for a prespecified internal pilot phase embedded within a pragmatic, two-arm, parallel-group RCT.

Methods The internal pilot will include the first four months of recruitment and aims to randomize at least 12 participants. Feasibility will be assessed across predefined domains, i.e., recruitment, eligibility, consent, intervention uptake, adherence, retention, data completeness, and treatment fidelity. Each domain is operationally defined and linked to prespecified progression criteria to ensure interpretability and decision-making utility. Criteria will be interpreted collectively to guide trial continuation. A minimal qualitative process evaluation will be embedded.

Ethics and dissemination The host trial has received ethical approval (N-20240046) and is registered at ClinicalTrials.gov (NCT07293130). The findings from the internal pilot will be reported in a separate feasibility manuscript.

Tommy Kjaergaard Nielsen, Pascal Madeleine, Annett Dalboege, Benjamin Steinhilber, and Anne Vingaard Olesen report no competing interests. Claus Kjaergaard is affiliated with teaching activities for the Danish Association of Mechanical Diagnosis and Therapy and the McKenzie Institute International; these roles are independent of and have not influenced the design, conduct, analysis, or reporting of this trial. 

NCT07293130

This study received partial financial support from the Karen Elise Jensen Foundation and the Danish Association of Mechanical Diagnosis and Therapy. The Institute of Occupational and Social Medicine and Health Services Research at the University of Tuebingen, where one author is employed, receives unrestricted institutional funding from the employers association of the metal and electrical industry in Baden-Wuerttemberg (Suedwestmetall). The funders had no role in the design of the study and will have no role in its conduct, data collection, management, analysis, interpretation, manuscript preparation, or decision to publish. The study is investigator-initiated and investigator-led.

I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.

Yes

The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

Ethics Committee of the North Denmark Region gave ethical approval for this work (N-20240046)

I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals.

Yes

I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).

Yes

I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable.

Yes

No datasets were generated or analyzed for this protocol. Data arising from the study will be made available upon reasonable request to the corresponding author, subject to applicable data protection regulations.