Castaldo 1981.

Methods	Retrospective review
Participants	419 patients from 1968 to 1977
Interventions	25 operations on 23 patients for bowel obstruction (2 patients underwent 2 operations)
Outcomes	Successful palliation: defined survival > 8 weeks = 20/25 (80%) Hospital stay, post operation: mean 26 days (1 to 89 days) Postoperative mortality: 3/23 (13%) Postoperative morbidity: 10 patients suffered 22 complications
Notes	No information on symptoms of successes Postoperative morbidity includes patients who died Complications: small bowel obstruction in 9, large bowel in 10 and combination in 6
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)	Unclear risk	Successful palliation is defined but there is no information regarding symptoms in these patients Postoperative morbidity includes patients who died Results not reported according to surgical intervention