Kwon 2007.

Methods	Method of randomisation: block randomisation (no other information) Assessor blinding: no blinding but independent assessment of clinical and radiological outcome measures Loss to follow‐up: patient‐reported outcomes: 9 were lost to follow‐up or refused to send in their self‐reported "outcome packages" radiographical outcomes: 5 lost to follow‐up
Participants	Country: Canada, at the Vancouver General Hospital, Vancouver, British Columbia Period of study recruitment: between 1998 and 2003 Total number: 42 participants Inclusion criteria Unilateral facet fracture, dislocation, or fracture dislocation between C3 and T1, with subluxation of < 25% of anteroposterior diameter of caudal vertebral body Injury amenable to either anterior or posterior approach Age ≥ 17 years Exclusion criteria Associated spinal cord injury Associated injury that would affect postoperative mobilisation Associated compression fracture of subjacent vertebral body > 10% of anterior height Narcotic or opioid allergy or addiction Inability to understand use of self‐controlled analgesia device Pre‐existing conditions that would affect postoperative mobilisation Documented disc herniation on magnetic resonance imaging Age Anterior group: 35.5 ± 3.6 years Posterior group: 33.0 ± 3.1 years Gender Male: 31 Female: 11
Interventions	Reduction was performed during the surgical procedure 1. Anterior procedure: anterior cervical discectomy + tricortical iliac crest autograft + plate fixation 2. Posterior procedure: lateral mass screw‐plate fixation and/or interspinous and/or oblique wiring Postoperative care: self‐controlled analgesia device provided to the participants; all mobilised with cervical orthoses (Guildford, Inc.) and were trained by occupational therapists in brace application. Standard physiotherapy regimen. Outpatient physiotherapy was not routine.
Outcomes	Length of follow‐up: 12 months Pain: 1st and 2nd postoperative days Clinical and radiographical outcomes: 6 weeks and 3, 6 and 12 months postoperatively Primary outcome Duration of postoperative time required to achieve a standard set of discharge criteria Secondary outcomes Neck pain: 1st and 2nd postoperative days (visual analogue score) Function and activities of daily living: 36‐item Short‐Form Survey and North American Spine Society cervical spine questionnaire questionnaires Radiographical outcomes: fusion and sagittal alignment Complications
Notes	The study population included the following types of unilateral facet injuries: fracture subluxations: 34, of which there were 9 isolated inferior facet fractures, 15 isolated superior facet fractures and 10 other fracture subluxations Purely ligamentous injuries without fracture: 8, of which facet was completely dislocated in 2, perched in 2 and subluxed in 4 Ten participants had single nerve root injury: 6 (anterior) versus 4 (posterior)
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	No details: "The patients were randomised according to a block randomisation procedure"
Allocation concealment (selection bias)	Unclear risk	No details provided
Blinding of participants and personnel (performance bias) All outcomes	High risk	No blinding for participants or treatment providers
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	No blinding. "Independent research assistants not involved in the patients’ clinical care administered all clinical outcome measures".
Incomplete outcome data (attrition bias) All outcomes	High risk	All participants lost to follow‐up or excluded were reported. However, their data were not presented. For patient‐reported outcomes: anterior group: 6 participants (30%) posterior group: 3 participants (14%) For radiographic outcomes: anterior group: 2 participants (10%) posterior group: 3 participants (14%)
Selective reporting (reporting bias)	Low risk	All the outcomes described in the methods section were presented in the results
Other bias	Unclear risk	Different types of instrumentation were used in both groups, especially in the posterior fixation group, in which lateral mass screws with plates and/or interspinous and/or oblique wiring were deployed.