Xu 2006.

Methods	A randomised, parallel group study comparing radiofrequency thermocoagulation (RFT) using the VectorVision navigation system to Hartel's technique of facial measurement. It is not clear if this study was double blind, and unclear if an independent observer was used. Day stay setting
Participants	Intervention: Gasserian RFT with navigation Diagnostic criteria of patients included in the trial             TN fulfilling criteria of International Association for the Study of Pain, no prior surgery MRI Age mean (range, SD)  63 (48 to 79, 5)      Gender 12 female, 14 male          Severity (mean, SD)  Not available Duration of condition years mean, range, SD)  5.3 (3 to 10, 1.2) years           Number            26           Control: Gasserian RFT without navigation Diagnostic criteria of patients included in the trial             TN fulfilling criteria of International Association for the Study of Pain, no prior surgery MRI Age mean (range, SD)  59 (45 to 73, 7) Gender               15 female, 13 male Severity (mean, SD)  No indication Duration of condition years mean, ( range, SD)  4.9 (2.5 to 12, 1.5) years Number          28
Interventions	Intervention: Gasserian RFT with navigation Type of intervention       VectorVision navigation system had frame attached 8 to 10 gauge needle, 1 mm exposed  Test with 2 Hz , 50 Hz, temperature of 45 °C for 30 s, repeated with further lesion temperature 75 °C for 60 s Repeated 2 to 3 more times till blunt to touch Antibiotics 3 to 4 days, other medications stopped Length of follow‐up 13 to 58, mean 36 + 7 months Control: Gasserian RFT without navigation Type of intervention       Hartel’s technique with measurement on the face 8 to 10 gauge needle, 1 mm exposed  Test with 2 Hz , 50 Hz, temperature of 45 °C for 30 s, repeated with further lesion temperature 75 °C for  60 s Repeated 2 to 3 more times till blunt to touch Antibiotics 3 to 4 days, other medications stopped Length of follow‐up 10 to 54, mean 34 + 5 months
Outcomes	Primary outcomes The patient's overall degree of improvement, that is: complete pain relief, partial satisfactory pain relief, partial unsatisfactory pain relief, no change and worse Outcome complete pain relief on Kaplan‐Meier Time of measurement 6 months, 1 year, yearly intervals Kaplan‐Meier Secondary outcome Morbidity Adverse events
Notes	A high risk of bias was identified in this study. This is a comparative study comparing 2 techniques for performing radiofrequency thermocoagulation. Few details are provided to determine the quality of the RCT, e.g. method of randomisation, blinding, outcome assessment, and the only outcome measure used was complete pain relief ascertained by a questionnaire at 3 months. Actuarial methodology shows that both techniques provide pain relief but this is more sustained if a neuronavigation system is used. This system also decreases side effects
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	High risk	"randomly divided into two groups" no details provided
Allocation concealment (selection bias)	High risk	No details provided
Blinding (performance bias and detection bias) All outcomes	High risk	Immediate effectiveness of the surgery which was based on the condition of the participants was recorded in hospital. Three months after being discharged, all the participants were sent questionnaires addressing the absence or presence of facial pain, its characteristics, duration and time of recurrence, adverse effects, complications and the need for further treatment. The data available from these records were processed and stored in a designed computer database. Outcomes only measured once by questionnaire and timing not known. No clear data provided on blinding of either patient or assessor.
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Unknown number lost to follow‐up
Selective reporting (reporting bias)	High risk	Used questionnaires at 3 months but not other times and study continued beyond this time
Other bias	Unclear risk	Not clear

TN: trigeminal neuralgia; VAS: visual analogue scale; SD: standard deviation; MRI: magnetic resonance imaging; RCT: randomised controlled trial; CT scan: computerised tomography scan.