|
| Bias | Study ID |
| Lundström et al. 2006 [23] | Sarikkola et al. 2011 [25] | Serrano-Aguilar et al. 2012 [24] |
|
| Random sequence generation (selection bias) | Unclear risk
“The patients were randomly assigned to ISCS or to DSCS.” No further description of randomization procedure | Low risk
“Randomization was performed using sealed envelopes after the preoperative examination” | Low risk
“A computer-generated sequence was used” |
|
Allocation concealment
(selection bias) | Unclear risk
Not described in paper | Unclear risk
Patients (and staff) knew after the preoperative assessment but before the surgery to which group they belonged | Unclear risk
“Random numbers were obtained for all patients on the waiting list before participants were selected on the basis of the inclusion and exclusion criteria. Randomization was performed sequentially for blocks of 200 patients.” Unclear whether those including the patients in the study were aware of the randomization status before inclusion/exclusion |
|
| Blinding of participants and personnel (performance bias) | High risk
Not possible to blind patients or personnel to whether the patient had ISBCS or different date bilateral surgery | High risk
Not possible to blind patients or personnel to whether the patient had ISBCS or different date bilateral surgery | High risk
Not possible to blind patients or personnel to whether the patient had ISBCS or different date bilateral surgery |
|
| Blinding of outcome assessment (detection bias) | Unclear risk
Not reported | Unclear risk
Not reported | Unclear risk
Not reported |
|
Incomplete outcome data
(attrition bias) | Unclear risk
High rate of exclusion after randomization/drop-outs (8/96 = 8.3%), not possible to assess whether this influenced the outcome since the characteristics of drop-outs were not compared to non-drop-outs | Low risk
96.0% in Group 1 and 97.3% in Group 2 were treated per protocol. 491/507 randomized patients had 1 month follow-up | Low risk
Low number of exclusions and drop-outs (<5% at the 1 month postoperative examination) |
|
| Selective reporting (reporting bias) | Low risk
Important outcomes were reported | Low risk
Important outcomes were reported | Low risk
Important outcomes were reported |
|
| Other bias | Low risk
Not likely in this study | Low risk
Not likely in this study | Low risk
Not likely in this study |
|
