Macdermid 2003.

Methods	Single centre RCT
Participants	Participants were randomised in an unbalanced design with a 3:1 probability of receiving an endoscopic procedure (91 ECTR, 32 OCTR). Age 45 ± 15 for ECTR and 53 ± 16 for OCTR. Women comprised 68% of both arms (demographics were similar between groups) CTS confirmed by electrophysiology, and participants had poor response to 6 months' conservative treatment
Interventions	2‐portal ECTR (transbursal ‐ Chow technique) vs OCTR
Outcomes	Follow‐up at 1 and 6 weeks and 3 months SSS, serious complications, grip strength, pinch strength, sensory threshold, pain (McGill pain questionnaire), time to return to work, rate of repeat procedures (at > 2 years follow‐up)
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	No information given in the manuscript
Allocation concealment (selection bias)	Unclear risk	No information given in the manuscript
Blinding of participants and personnel (performance bias) All outcomes	High risk	No information given. Participants and personnel could not be blinded
Blinding of outcome assessment (detection bias) All outcomes	Low risk	The authors state that "all evaluations were performed by a blinded evaluator" , although there was no additional information given regarding the way of blinding (eg gloves used)
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	No information given in the manuscript regarding potentially losses to follow‐up and how they were addressed
Selective reporting (reporting bias)	Unclear risk	The authors only provide diagrams, with no SDs or P values
Other bias	Unclear risk	Groups were similar at baseline but only in demographics. No statistical analysis was provided regarding measurements at baseline, although such measurements had been conducted The authors declare no conflict of interest or financial support