Celik 2010.

Methods	Single‐centre RCT Setting: Department of Neurosurgery, Beyoglu State Hospital, Istanbul Country: Turkey Period: July 2001 to May 2003
Participants	Number: 80 patients (40/40) Diagnosis: dynamic x‐rays, thin‐sliced CT and MRI; severe back/leg pain and neurogenic claudication; anteroposterior diameter less than 10 mm of the lumbar spinal canal by CT scan and MRI Included: patients who had not responded to conservative medical therapy and physical therapy; more than 41% in ODI; more than 7 in VAS pain; walking distance less than 30 meters; severe lumbar spinal stenosis clinically Excluded: patients requiring discectomy or showing any kind of instability before the surgery Age (years): mean (SD) 61 (13)/59 (14)
Interventions	Group 1: total laminectomy Group 2: bilateral micro decompressive laminotomy. Medial facetectomy and wide foraminotomies were performed at the level of stenosis, preserving the lateral aspect of the facet joints. No patient received discectomy. Follow‐up: 60 months
Outcomes	Pain: 10 cm VAS leg pain Disability: ODI, walking distance Operation time Perioperative blood loss Complications Reoperations
Notes	Surgeon's experience: "both groups of patients were operated by the same senior surgeon in the same time period" Funding: Conflict of interest and financial support were not reported in this study.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: "a chart system was used to process randomizaton".
Allocation concealment (selection bias)	Low risk	Quote: "a registered nurse informed surgeons about the type of surgery before the operation".
Blinding of participants (performance bias) All outcomes	Low risk	Quote: "patients were not informed as which group they would be placed".
Bliding of personnel/ care providers (performance bias)	High risk	The surgeon could not have been blinded to the intervention.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Quote: "the patients were preoperative examined and followed at regular intervals by the operating neurosurgeons and by a neurology specialist blinded to the study protocol."
Incomplete outcome data (attrition bias) All outcomes	Low risk	71/80 = 89% of the patients completed the follow‐up. The number of drop‐outs is unlikely to affect the results.
Intention‐to‐treat analysis (attrition bias)	Unclear risk	No information about intention‐to‐treat analysis.
Selective reporting (reporting bias)	Low risk	It was clear that the published report included all expected outcomes.
Group similarity at baseline (selection bias)	Low risk	There were no preoperative differences between groups, based on Tables 1 to 3.
Co‐interventions (performance bias)	Low risk	Only the surgical technique differed between treatment groups.
Compliance (performance bias)	Low risk	Compliance in both treatment groups: 100% (surgery).
Timing of outcome assessment (detection bias)	Unclear risk	All important outcome assessments for both groups were measured at the same time.
Other bias	Unclear risk	Conflict of interest and financial support were not reported in this study.