Kenefick 2002#.

Methods	Randomised crossover trial Blinding: participant and investigator Follow‐up: the study consisted of two 2‐week intervals with subsensory stimulation either 'on' or 'off' Setting: single centre UK Withdrawals: none Intention‐to‐treat analysis: yes
Participants	Enrolled: 2 Age: both aged 36 Gender: female (2) Duration of symptoms: not stated Received permanent implant: 2 Inclusion criteria: failed maximal conservative treatment; psychologically stable; normal sigmoidoscopy; prolonged whole gut transit time; delayed evacuation Exclusion criteria: not stated
Interventions	Both participants had a successful 3‐week trial of percutaneous stimulation before one‐stage permanent implantation of a stimulator to the S3 foramen. A Intervention: stimulator On for two weeks with subsensory stimulation B Control: stimulator Off No treatment‐free period between the weeks
Outcomes	Bowel frequency (per 2 weeks); time with pain and bloating (%); Wexner constipation score (0 to 30); Symptom analogue score (0 to 100); anal manometry
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Unclear: 'Randomised crossover trial'.
Allocation concealment (selection bias)	Unclear risk	Unclear: 'Randomised crossover trial'.
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Participants blinded.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Outcome assessor blinded.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Results were reported for everyone who entered the studies and the participants were analysed in the groups to which they were originally allocated, effectively resulting in an intention‐to‐treat analysis.
Selective reporting (reporting bias)	Unclear risk	The results of the Short Form 36 quality of life questionnaire were not reported in results table.
Other bias	Low risk	None identified.