When Two Is Better Than One: A Pilot Study on Transcranial Magnetic Stimulation Plus Muscle Vibration in Treating Chronic Pelvic Pain in Women

Abstract

Chronic pelvic pain syndrome (CPPS) affects about 4-16% of adult women, and about one-third of them require medical assistance due to severe symptoms. Repetitive transcranial magnetic stimulation (rTMS) over the supplementary motor area (SMA) has been shown to manage pain in refractory CPPS. Focal muscle vibration (FMV) has also been reported to relieve pelvic pain. The objective of this study was to assess the feasibility and effect of rTMS coupled with FMV to reduce pain in seven adult women with refractory CPPS. This pilot, open-labeled, prospective trial examined treatment by 5 Hz rTMS over SMA and 150 Hz FMV over the perineum, suprapubic, and sacrococcygeal areas, with one daily session for five consecutive days for three weeks. We assessed tolerance and subjective pain changes (as per visual analog scale, VAS) until one month post-treatment, with a primary endpoint at day 7. No patients experienced serious adverse effects or a significant increase in pain. Six out of seven patients experienced a VAS improvement of at least 10% at T7; three of these individuals experienced a VAS improvement of more than 30%. Overall, we found a significant VAS reduction of 15 points (95% CI 8.4-21.6) at T7 (t = 6.3, p = 0.001; ES = 2.3 (1.1-3.9)). Three of the women who demonstrated a significant VAS reduction at T7 retained such VAS improvement at T30. VAS decreased by six points (95% CI 1.3-10.7) at T30 (t = 3.1, p = 0.02; ES = 1.5 (0.2-2.6)). This coupled approach seems promising for pain management in adult women with refractory CPPS and paves the way for future randomized controlled trials.

Keywords: chronic pelvic pain syndrome (CPPS); focal muscle vibration (FMV); pelvic floor muscles (PFMs); repetitive transcranial magnetic stimulation (rTMS); supplementary motor area (SMA).

Figure 1

(a) Experimental study design. (b) SMA rTMS site and cup-like and pen-like probe sites for FMV. (c) Single-pulse TMS stimulation sites. Legend: AH: abductor halluces; AMT: active motor threshold; FDI: first dorsal interosseous; FMV: focal muscle vibration; M1: primary motor cortex; rTMS: repetitive transcranial magnetic stimulation; SMA: supplementary motor area; T0: baseline; T30: follow-up visit 30 days after the end of the stimulation protocol; T7: follow-up visit seven days after the end of the stimulation protocol.

Figure 2

Average values of the outcome measures. Data are reported as mean with standard deviation; * indicates a significant T7-T0 or T30-T0 change (*** p < 0.001; ** p < 0.01; * p < 0.05). Legend: VAS: visual analog scale; T0: mean scores of the 30 days before the first treatment session; T7: 7-day follow-up visit. T30: 30-day follow-up visit; BPI: Brief Pain Inventory short form; BDI: Beck’s Depression Inventory; QOL: Flanagan’s Quality of Life.