Ellis 1991.

Methods	Retrospective review
Participants	134 patients (138 procedures) from 1979 to 1989
Interventions	26 patients had a malignant cause of bowel obstruction confirmed
Outcomes	Successful palliation: the ability to tolerate regular oral feeding at discharge; 20/26 (77%) Operative mortality: death occurring before discharge; 6/26 (23%) Morbidity: 14/26 (54%)
Notes	Figures in the table do not add up (20/26 calculated from data in paper) All 26 patients had resection or anastomosis No indication what morbidity was
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	High risk	Patients allocated to surgery by clinician/patient choice and retrospectively reviewed
Allocation concealment (selection bias)	High risk	Patients allocated to surgery by clinician/patient choice and retrospectively reviewed
Blinding (performance bias and detection bias) All outcomes	High risk	Patients allocated to surgery by clinician/patient choice and retrospectively reviewed
Blinding of participants and personnel (performance bias) All outcomes	High risk	Patients allocated to surgery by clinician/patient choice and retrospectively reviewed
Blinding of outcome assessment (detection bias) All outcomes	High risk	Patients allocated to surgery by clinician/patient choice and retrospectively reviewed
Selective reporting (reporting bias)	High risk	Figures in table do not add up