Usman 2013.

Methods	Single‐centre RCT Setting: Neurosurgery department of PGMI, Lady Reading Hospital, Peshawar Country: Pakistan Period: January 2010 to December 2010
Participants	Number: 60 patients (30/30) Diagnosis: physical examination and radiological/neuroimaging evidence Included: patients with symptoms of radiculopathy or neurogenic claudication; radiological/neuroimaging evidence of lumbar spinal stenosis involving the central canal and/or foraminal stenosis; failure of conservative treatment with medication and physiotherapy for a minimum of three months Excluded: Patients with spondylolisthesis; associated co‐morbid conditions; recurrent lumbar spinal stenosis Age (years): 73.4% between 31‐50 years old
Interventions	Group 1: conventional laminectomy Group 2: unilateral approach for bilateral decompression. Unilateral laminotomy was performed with partial resection of the inferior aspect of the cranial hemilamina and the superior aspect of the caudal hemilamina. Bilateral flavectomy was performed, and the lateral recess and neural foramina were decompressed contralaterally Follow‐up: minimum 3 months
Outcomes	Operation time Length of hospital stay
Notes	Surgeon's experience: not reported 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 total of 60 patients with lumbar stenosis were randomly assigned to undergo either a conventional laminectomy, or a unilateral approach."
Allocation concealment (selection bias)	Unclear risk	Not mentioned.
Blinding of participants (performance bias) All outcomes	Unclear risk	No mention of any attempts to blind the participants.
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: "a database was compiled using inpatients and outpatients medical records by an independent observer who was not part of the operative team and/or in patient care."
Incomplete outcome data (attrition bias) All outcomes	Low risk	100% of the patients completed the follow‐up.
Intention‐to‐treat analysis (attrition bias)	Unclear risk	No information about intention‐to‐treat analysis.
Selective reporting (reporting bias)	High risk	In the methods the authors reported that recovery rate was assessed as an outcomes measure. However, in the results the authors do not report data for this outcome.
Group similarity at baseline (selection bias)	Unclear risk	No information about patients characteristics at baseline.
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	Not mentioned.
Other bias	Unclear risk	Conflict of interest and financial support were not reported in this study.