Does output voltage influence the clinical effects of pulsed radiofrequency of the suprascapular and axillary nerves in chronic shoulder pain? A double-masked, non-randomized comparative study.

Abstract

Aims: Chronic shoulder pain can cause substantial disability. This study evaluated whether increasing pulsed radiofrequency (PRF) output voltage from 45 V to 85 V provides additional benefit when treating the suprascapular and axillary nerves.

Patients and methods: In this prospective, double-masked, non-randomized comparative study, 80 patients (40 per group) with refractory chronic shoulder pain underwent ultrasound-guided PRF at 45 V or 85 V using otherwise identical parameters. The primary outcome was pain intensity (visual analog scale [VAS]); secondary outcomes included QuickDASH, SF-12, HADS, patient global improvement, analgesic use, and safety. Outcomes were assessed over 6 months using a repeated-measures general linear model.

Results: At 6 months, estimated marginal mean VAS scores were 5.89 (95% CI 5.18-6.59) with 45 V and 5.47 (95% CI 4.92-6.02) with 85 V. Neither the group effect (p = 0.137) nor group-by-time interaction (p = 0.815) was significant. QuickDASH scores were 53.84 (95% CI 48.02-59.66) and 49.86 (95% CI 44.30-55.42), respectively, with a significant group-by-time interaction (p = 0.018).

Conclusions: Increasing PRF voltage from 45 V to 85 V was not associated with a significant difference in pain trajectories, although small differences in secondary outcomes cannot be excluded.