Posterior Tibial Nerve Stimulation did not Improve Fibromyalgia Symptoms

Adding posterior tibial nerve stimulation (PTNS) to existing pharmacological treatment did not reduce pain or improve quality of life in patients with fibromyalgia, according to a study published in Journal of Clinical Medicine.¹

Peripheral nerve stimulation works by targeting a nerve trunk with subcutaneous or transcutaneous electrical stimulation, which can improve pain and neuromodulation. The approach reduces levels of glutamate and substance P, while increasing serotonin and GABA levels, all of which are affected in patients with fibromyalgia. PTNS, specifically, is currently used to manage conditions including chronic pelvic pain, chronic prostatitis, fecal incontinence, and overactive bladder. Additional benefits of this approach are its ease of application, lack of side effects, and allows for patients to perform it on themselves.²

“Considering the pathophysiology of fibromyalgia and the mechanisms of peripheral nerve stimulation, we hypothesized that posterior tibial nerve stimulation might be used in fibromyalgia,” wrote İlker İlhanlı, MD, PhD, associated with the Department of Physical Medicine and Rehabilitation, Ondokuz Mayıs University, Turkey, and colleagues. “By affecting the central and peripheral mechanisms involved in the pathophysiology of fibromyalgia, which is thought to have neuropathic pain component, it was assumed that the posterior tibial nerve stimulation would reduce the pain, improve quality of life, and decrease disease severity of patients.”

The prospective, single-blind, parallel-group, randomized controlled trial enrolled female patients with newly diagnosed fibromyalgia receiving 30 mg/day duloxetine treatment at the Giresun University Giresun Training and Research Hospital and Ondokuz Mayıs University Faculty of Medicine Physical Therapy and Rehabilitation Outpatient Clinic, in Turkey. In addition to the medication, patients in the intervention cohort received 6 sessions of PTNS, twice weekly, with 3 – 4 days in between each session. Controls received duloxetine treatment only.

All participants were assessed at baseline, month 1, and month 3 to determine changes in pain, quality of life, disease severity, and functional status. Pain was evaluated using the short-form McGill Pain Questionnaire (SF-MPQ) and the numeric rating scale (NRS), quality of life was assessed using the 36-item short-form health survey (SF-36), and functional status and disease severity was determined using the Fibromyalgia Impact Questionnaire (FIQ).

In total, 22 patients were included into the PTNS intervention cohort, and 30 patients were placed in the control group. Pain and FIQ scores improved across both groups. Both groups reported improved vitality in the 1st month, according to SF-36 scores, although no significant changes in other quality of life subscales were observed in either cohort.

No statistical differences between the intervention group and the control group were observed regarding changes in pain, SF-36 scores, and FIQ compared with baseline, month 1, and month 3. No complications, serious adverse events, or infections were reported due to pharmacological treatment or PTNS during the study period.

Investigators noted a lack of generalizability in their findings, as the study only included female patients. Additionally, they did not standardize or evaluate other non-pharmacological treatment options, including diet or exercise, which may have affected the results of PTNS treatment. Lastly, investigators did not evaluate the neuropathic component of fibromyalgia using a neuropathic pain-specific test pre- and post-intervention. However, this study was the first to test the efficacy of PTNS in this patient population.

“Further studies with large sample size investigating the effects of PTNS application at different sessions, durations, doses, and frequencies, and peripheral stimulation of other nerves will contribute additional findings to the literature,” investigators concluded.

References

1. ^{Sarı İF, İlhanlı İ, Mızrak T, Kulaklı F, Kasap Z. The Effect of Transcutaneous Posterior Tibial Nerve Stimulation on Pain and Quality of Life in Patients with Fibromyalgia: A Single-Blind, Randomized Controlled Trial. J Clin Med. 2023;12(15):4989. Published 2023 Jul 29. doi:10.3390/jcm12154989}
2. ^{Kabay, S.; Kabay, S.C.; Yucel, M.; Ozden, H. Efficiency of posterior tibial nerve stimulation in category IIIB chronic prostatitis/chronic pelvic pain: A Sham-Controlled Comparative Study. Urol. Int. 2009, 83, 33–38}