Hoefnagels 1997.

Methods	RCT
Participants	Mean age 51 years (range 21 to 87 years), 74% women. Mean duration of complaints 21 months. Mean SSS (SD) 3.0 (0.8) vs 2.9 (0.8) ECTR vs OCTR. Mean FSS 2.1 (0.7) vs 2.2 (0.7) Electrophysiologically confirmed CTS
Interventions	(1) ECTR: 1‐portal Agee technique (87 participants) (2) OCTR (91 participants)
Outcomes	SSS, FSS, pinch strength (Citec manometer), pain and tingling (10‐point VAS scale), electroneurophysiological tests at 3 months, satisfaction with result, return to work, complications
Notes	Study conducted in the Netherlands, published in Dutch only
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	No information given ("A research nurse randomly assigned the patients to ...")
Allocation concealment (selection bias)	Unclear risk	No information given ("A research nurse randomly assigned the patients to ...")
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	High risk	No information given. Participants and personnel could not be blinded
Incomplete outcome data (attrition bias) All outcomes	Low risk	Dropout rate described and acceptable (2 participants in ECTR group dropped out: in 1 participant ECTR could not be performed, in another participant the ECTR equipment was not available. Both participants were treated with OCTR and were left out of the analyses
Selective reporting (reporting bias)	Low risk	All outcomes presented in the results were mentioned in the methods section
Other bias	Low risk	Groups similar at baseline. Funded by a grant from Dutch MRC. No information on conflicts of interest