Gallagher 1994.

Methods	RCT
Participants	Departments of Pain Relief, Rheumatology and Orthopaedics, Guy's Hospital, London, UK (N = 41) Inclusion criteria Back pain > 3 months Age 25 to 55 years and ≥ 4 of the following: Tenderness on palpation More pain on extension than on flexion Pain on rotation of the spine Referred pain (above the knee) Pain exacerbated by exercise and relieved by rest Pain exacerbated by sitting or standing Pain not exacerbated by coughing or sneezing Radiological evidence of facet joint degeneration or predisposing factors Pain relief over 12 hours after local anaesthetic  Exclusion criteria Previous back operations Neurological signs of nerve root compression in lower limbs Patients with major mental illness or severe personality disorder Pending compensation claims General ill health
Interventions	Experiment group After area was anaesthetised (nerves above and below and the painful nerve) with lignocaine 2% 0.5 mL, RF lesion was made at 80°C for 90S of medial branch of posterior primary ramus of lumbar segmental nerves Group A (N = 18): good response to diagnostic block + denervation Group B (N = 6): equivocal response to diagnostic block + denervation Control  group Nerves to joints were identified by stimulation, local anaesthetic was injected in the usual way, but no heat lesion was made Group C (N = 12): good response to diagnostic block + placebo Group D (N = 5): equivocal response to diagnostic block + placebo
Outcomes	Significant differences in mean pain scores (VAS 0 to 100) between groups A and C at 1 month and at 6 months Pain intensity: change in VAS score at 1 month: ‐17 (A), ‐13 (B), ‐13 (C), ‐12 (D) Pain intensity: change in VAS score at 6 months: ‐7 (A), ‐5 (B), ‐3 (C), ‐17 (D)
Notes	Dropouts: number unclear
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Remained unclear from text
Allocation concealment (selection bias)	Unclear risk	Remained unclear from text
Blinding (performance bias and detection bias) All outcomes ‐ patients?	Low risk	Placebo procedure indistinguishable from intervention
Blinding (performance bias and detection bias) All outcomes ‐ providers?	Unclear risk	Remained unclear from text
Blinding (performance bias and detection bias) All outcomes ‐ outcome assessors?	Low risk	Participant reported outcome measures by blinded participants
Incomplete outcome data (attrition bias) All outcomes ‐ drop‐outs?	Unclear risk	Remained unclear from text
Incomplete outcome data (attrition bias) All outcomes ‐ ITT analysis?	Unclear risk	Remained unclear from text
Selective reporting (reporting bias)	Unclear risk	No protocol available
Baseline characteristics similar?	Low risk	No differences between groups in terms of age or duration of pain
Co‐interventions avoided or similar?	Unclear risk	Remained unclear from text
Compliance acceptable?	Low risk	Irrelevant: single‐session intervention
Timing of outcome assessments similar?	Low risk	Participants assessed before any treatment, before denervation, at 1 month and at 6 months