Przeklasa‐Muszynska 2006.

Methods	A parallel group, randomised prospective study
Participants	Intervention: radiofrequency thermocoagulation (RFT) + steroid Diagnostic criteria of patients included in the trial             Not available Age mean (range)  65 (49 to 83) Gender 14 female, 8 male Severity VAS 0 to 10, 8.4 McGill Pain Questionnaire 38.9 ± 11.5 Duration of condition mean (range) years 9.8 (0.8 to 40) years Number   22          Intervention: RFT + pentoxyphilline Diagnostic criteria of patients included in the trial             Not available Age mean (range)  65 (49 to 83) Gender 13 female, 8 male Severity VAS 8.5 McGill Pain Questionnaire 43.4 ± 14.9 Duration of condition mean (range) years 9.8 (0.8 to 40) Number   21          Control: RFT only Diagnostic criteria of patients included in the trial             Not available Age mean (range)  65 (49 to 83) Gender 14 female, 8 male Severity VAS 8.1 McGill Pain Questionnaire 41.1 ± 11.4 Duration of condition mean (range) years 9.8 (0.8 to 40) Number   22
Interventions	Intervention: RFT + steroid Type of intervention       Radiofrequency thermocoagulation at Gasserian ganglion using 5 mm needle, 3 x 30 s 21 mV at 50 mA with 40 mg methylprednisolone Length of follow‐up mean 2 hrs, 7 days, 30 days, 90 days Intervention: RFT + pentoxyphilline Type of intervention   Radiofrequency thermocoagulation at Gasserian ganglion using 5 mm needle, 3 x 30 s 21 mV at 50 mA with 10 mg pentoxyphilline Length of follow‐up mean 2 hrs, 7 days, 30 days, 90 days Control: RFT only Type of intervention   Radiofrequency thermocoagulation at Gasserian ganglion using 5 mm needle, 3 x 30 s 21 mV at 50 mA with 2 ml normal saline Length of follow‐up mean 2 hrs, 7 days, 30 days, 90 days
Outcomes	Primary outcome Pain relief on the VAS Time of measurement: 6 months, one year and at yearly intervals (Kaplan‐Meier) Secondary outcome VAS McGill Pain Questionnaire Adverse events
Notes	This RCT determines whether the injection of a steroid or pentoxyphilline ( agent to reduce inflammatory response) at the time of the radiofrequency thermocoagulation affects outcome at 90 days. Nearly 30% of patients received no benefit from RFT but this was reduced in the pentoxyphilline group at 90 days. There was some reduction in side effects in terms of swelling and sensory change when using pentoxyphilline. There are no details provided on randomisation, how bias was removed or of completeness of follow‐up. A power calculation was not done.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	High risk	In English abstract say “ randomly divided” in Polish abstract and text “ divided” but no mention of the word random
Allocation concealment (selection bias)	Unclear risk	No mention of concealment
Blinding (performance bias and detection bias) All outcomes	Unclear risk	Not mentioned
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	No mention of completeness of follow‐up
Selective reporting (reporting bias)	Unclear risk	Incomplete data
Other bias	Unclear risk	None mentioned