van Dalen 2003.

Methods	Randomisation by closed envelope system                                                     Design of RCT: parallel clinical trial                                                    Power calculation: not stated                                                  No blinding used                                                         "Time of follow up: only in patients in whom an appendectomy was not performed was undertaken in September 2001"                                                   63 women of 163 participants with appendicitis diagnosis No participants excluded after random assignment                                                      Participants lost to follow‐up: not clearly stated                                                    60 women analysed                                                   Single centre: Department of Surgery, Christchurch Hospital, Christchurch, New Zealand                                                 Enrolment from July 1991 to July 1992                                                  Source of funding: not stated Ethical issues: ethical approval obtained from the Canterbury Ethics Committee  Method used to establish definitive diagnosis: visual examination of appendix and abdominal cavity and histopathological examination of appendix when removed in laparoscopic group. Not clearly stated in conventional group, but in all participants, appendix removed and sent for histopathological study
Participants	"Female patients aged between 16 and 45 years with a clinical diagnosis of acute appendicitis were eligible for inclusion in the study. Suitable patients in whom a decision had been made to proceed to appendectomy were asked to participate in the study. They were excluded if informed consent was not obtained, or if laparoscopy was contraindicated"                                                          Mean age (range): 24 years (16 to 45) in laparoscopy group, 22 years (16 to 51) in conventional group                                                Mean temperature (range): 37.3 °C (36 to 38.4) in laparoscopy group, 37 °C (35.2 to 39.5) in conventional group                               Mean serum white cell count (range): 13,000 (4200 to 21,500) in laparoscopy group, 13,100 (7100 to 22,000) in conventional group                                                     Duration of pain (range): 35.5 days (five to 120) in laparoscopy group and 43.3 days (six to 168) in conventional  group
Interventions	Laparoscopy first or open appendicectomy performed directly                                                     If appendix clearly seen and looking normal, no appendicectomy carried out. If other pathology seen, this was dealt with appropriately. If inflamed appendix seen or evidence thereof, or if appendix could not be seen, open appendicectomy carried out                                                            Those assigned to appendicectomy group: routine open appendicectomy and other pathology dealt with as necessary
Outcomes	Mean operating time: not defined or stated in methods, only reported                           Total days of stay: not defined or stated in methods, only reported                                                            Median postoperative stay: not defined or stated in methods, only reported                                                     Diagnostic accuracy: not defined or stated in methods, only reported
User defined 1
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Only mentioned the word "randomised". No further description provided
Allocation concealment (selection bias)	Unclear risk	Publication: states that sealed envelopes were used
Blinding (performance bias and detection bias) All outcomes	High risk	Open RCT
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Not clear whether follow‐up was similar in the two groups. Three of 63 lost to follow‐up
Selective reporting (reporting bias)	Unclear risk	Protocol of the study not available
Free of differential verification bias	Unclear risk	Definitive diagnosis not done with the same reference standard in the two groups
Free of partial verification bias	Unclear risk	Non‐random set of participants not undergoing the reference standard
Free of Incorporation Bias	High risk	Index test incorporated as the reference standard in the laparoscopic group
Other bias	Unclear risk	All baseline characteristics not reported

Abbreviations

CT = computed tomography.

GSRS = Gastrointestinal Symptom Rating Scale.

IUD = intrauterine device.

NSAP = non‐specific abdominal pain.

NSLAP = non‐specific lower abdominal pain.

PGWB = Psychological General Well Being Index.

PID = pelvic inflammatory disease.

RCT = randomized controlled trial.

SD = standard deviation.

STD = sexually transmitted disease.

US = ultrasonography.