Werner 2005.

Methods	Quasi‐randomised single‐blind controlled trial Blinded assessors Ethics approval and informed consent obtained
Participants	Total N = 161 (161 wrists) randomised Intervention group N = 86 wrists randomised, 63 wrists completed Control group N = 75 wrists randomised, 49 wrists completed 55 males, 57 females* Mean ± SD (range) age:* Intervention group: 44.74 ± 1.02 (25.6 to 59.0) yrs Control group: 43.77 ± 1.44 (25.5 to 59.2) yrs Inclusion criteria: 1. Worker‐reported symptoms of numbness, tingling, burning, or pain in the wrist or the hand for more than a week or more than 3 times in the last 6 months 2. Hand diagram was suggestive of CTS; that is, there were symptoms of numbness, tingling, burning, or pain in the median nerve distribution Exclusion criteria: 1. Upper‐extremity musculoskeletal disorders secondary to acute trauma on or off the job 2. History of bilateral carpal tunnel release (CTR) surgery 3. Pregnancy
Interventions	Intervention: Customised wrist splints and ergonomic education ‐ participants were fitted with a custom wrist‐hand orthosis that maintained the wrist in a neutral posture, and was worn at night for 6 weeks. Participants received instructions in how to reduce ergonomic stressors in the work and home environments by viewing a 20‐minute video on CTS and ergonomic risk factors. Control: Ergonomic education alone via the same 20‐minute video on CTS and ergonomic risk factors presented to participants in the intervention group.
Outcomes	Outcomes assessed at baseline, and three**, six**, and a mean of 12 months (range 7 to 15 months) follow‐up (after the end of treatment): 1. Symptoms using carpal tunnel questionnaire (rates 11 items on ordinal scale 1: mildest, to 5: most severe) 2. Elbow and forearm, and wrist, hand and finger discomfort using a 30‐day worst‐discomfort rating on a 0 to 10 VAS 3. Surgical rates for CTS 4. Nerve conduction: median nerve sensory peak latency (msec), median nerve sensory amplitude (µv), median‐ulnar peak latency difference (msec) 5. Data in Occupational Health and Safety Administration logs, plant medical records, disability records, days of work missed due to upper extremity problems, and workers’ compensation status or work restrictions collected from computerised records*** 6. Splint usage and satisfaction (only in the intervention group) using a questionnaire administered at the end of the 6‐week treatment period
Notes	*Data only reported for participants completing treatment (n = 112) **According to the authors, half of the participants did not complete the questionnaires at 3 and 6 month follow‐up, so no data from these time points were reported. ***This was not a pre‐specified outcome of this review, so data were not entered into RevMan. In participants with bilateral CTS, the wrist with the most severe symptoms was chosen for treatment and evaluation, so a unit of analysis error resulting from the correlation between two wrists in bilateral CTS participants could not have occurred.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	High risk	Quote: "Subjects were randomized to either a treatment or a control group, depending on whether the last digit of their Social Security number was odd or even." Comment: The trial authors used a non‐random component in the sequence generation process.
Allocation concealment (selection bias)	High risk	Quote: "Subjects were randomized to either a treatment or a control group, depending on whether the last digit of their Social Security number was odd or even. Subjects were not informed of the sequence for random allocation nor were they told to which group they were assigned until after consenting to participate." Comment: The trials authors did not adequately conceal the treatment allocation until interventions were assigned, as a non‐random process was used.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Quote: "Subjects were not blinded to their treatment, and the primary outcome measure was a self‐reported symptom severity score." Comment: Participants were probably not blinded to treatment allocation.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Quote: "The nerve conduction data were collected at baseline and at the 12‐month follow‐up. Subjects reported to the medical department to have the testing done during regular work hours, and the person doing the testing was blinded to the treatment assignment." Comment: The outcome assessor of nerve conduction data was probably blinded, but it is not reported whether surgical rates and extraction of medical records were done by someone blinded to treatment assignment
Incomplete outcome data (attrition bias) 3 months or less	High risk	Quote: "Data collection was incomplete at the 3‐ and 6‐month follow‐up periods. Subjects were contacted by a study site coordinator and were reminded to fill out the questionnaire, but about half of the subjects did not complete the 3‐ or 6‐month questionnaires. The trend in outcome measures at 3 and 6 months was similar to the results at 12 months." Comment: Data not complete for all outcomes, with no explanation as to how this may have impacted on the data reported.
Incomplete outcome data (attrition bias) After 3 months	High risk	Quote: "The 12‐month follow‐up data are presented because they represent a more complete data set...The 12‐month follow‐up was actually a range of follow‐up times, with an average of 12 months and a range of 7 to 15 months." Comment: Data not complete for each outcome, with no explanation as to how this may have impacted on the data reported.
Selective reporting (reporting bias)	High risk	Comment: The results of the following outcomes were not reported, despite being mentioned as being collected in the Methods section of the trial: Occupational Health and Safety Administration logs, disability records, days of work missed due to upper extremity problems, and workers' compensation status or work restrictions  collected from computerised records at baseline and 12 months' follow‐up, and nerve conduction data at 12 months' follow‐up.
Other bias	Low risk	Comment: No other sources of bias identified.