Peripheral nerve stimulation (PNS) may be a viable treatment option for patients with facial trigeminal neuropathic pain (TNP), according to results of a systematic review and meta-analysis published in Neuromodulation.
Researchers from Central South University in China searched publication databases through October 2020 for studies of neuropathic pain and implantable neurostimulators. A total of 13 studies comprising 221 patients were included in the final analysis.
Patients were mostly women (59.7%) with TNP (85%). Other diagnoses included atypical trigeminal neuralgia, herpes zoster ophthalmicus, postherpetic neuralgia, persistent idiopathic facial pain, supraorbital neuralgia, symptomatic trigeminal neuralgia, trigeminal deafferentation pain, temporomandibular joint disorder, trigeminal neuralgia, and headache.
The response rate to PNS (pain relief of >50%) was 60.2% (95% CI, 41.9% to 76.1%; I2, 70.733%; P <.0001). Compared with baseline, PNS was associated with an improvement in pain scores of 2.363 (95% CI, 1.408-3.319; I2, 85.723%; P <.0001).
Stratified by subgroup, the response rates of the combined etiologies was 69.1% (95% CI, 42.8% to 87.0%; I2, 76.315%; P =.001) and among the TNP subgroup, the response rate was 47.0% (95% CI, 23.5% to 71.9%; I2, 62.160%; P =.048).
Stratified by PNS target, the response rate for gasserian ganglion stimulation was 29.3% (95% CI, 19.2% to 41.8%; I2, 0%; P =.635), 77.6% for peripheral branch stimulation (P <.0001), and 52.2% (95% CI, 32.5% to 71.2%; I2, 0%; P =1) for trigeminal nerve root stimulation.
Frequently reported adverse events included displacement of electrodes, infection, physical discomfort, surgical revision, and loss of efficacy.
This analysis was limited by the fact that no studies were of randomized designs, significant heterogeneity was observed, and the combined etiology group had few patients with multiple diagnoses.
The study authors concluded PNS may be a viable treatment option for patients with TNP, especially among patients who are not candidates for conventional therapies. Stimulation of the trigeminal peripheral branches may be more effective than stimulation of the gasserian ganglion. Additional randomized trials are needed.
Ni Y, Yang L, Han R, et al. Implantable peripheral nerve stimulation for trigeminal neuropathic pain: a systematic review and meta-analysis. Neuromodulation. Published online May 18, 2021. doi:10.1111/ner.13421