A randomised sham-controlled study evaluating rTMS analgesic efficacy for postherpetic neuralgia

Abstract

ContextPostherpetic neuralgia (PHN) is a refractory neuropathic pain condition in which new treatment options are being developed. Repetitive transcranial magnetic stimulation (rTMS) may have the potential to reduce pain sensations in patients with postherpetic neuralgia.ObjectivesThis study investigated the efficacy on postherpetic neuralgia by stimulating two potential targets, the motor cortex (M1) and the dorsolateral prefrontal cortex (DLPFC).MethodsThis is a double-blind, randomised, sham-controlled study. Potential participants were recruited from Hangzhou First People’s Hospital. Patients were randomly assigned to either the M1, DLPFC or Sham group. Patients received ten daily sessions of 10-Hz rTMS in 2 consecutive weeks. The primary outcome measure was visual analogue scale (VAS) assessed at baseline, first week of treatment (week 1), post-treatment (week 2), 1-week (week 4), 1-month (week 6) and 3-month (week 14) follow-up.ResultsOf sixty patients enrolled, 51 received treatment and completed all outcome assessments. M1 stimulation resulted in a larger analgesia during and after treatment compared to the Sham (week 2 – week 14, p < 0.005), as well as to the DLPFC stimulation (week 1 – week 14, p < 0.05). In addition to pain, sleep disturbance was significantly improved and relieved by targeting either the M1 or the DLPFC (M1: week 4 – week 14, p < 0.01; DLPFC: week 4 – week 14, p < 0.01). Moreover, pain sensations following M1 stimulation uniquely predicted improvement in sleep quality.ConclusionM1 rTMS is superior to DLPFC stimulation in treating PHN with excellent pain response and long-term analgesia. Meanwhile, M1 and DLPFC stimulation were equally effective in improving sleep quality in PHN.Clinical trial registrationhttps://www.chictr.org.cn/, identifier ChiCTR2100051963.

The efficacy of repetitive transcranial magnetic stimulation in postherpetic neuralgia: a meta-analysis of randomized controlled trials

“…It is noteworthy that our study observed that rTMS in both the DLPFC and M1 regions led to a significant reduction in VAS, but no statistical difference was detected between them ( p = 0.98). This finding differs from Wang et al ( 11 ), who suggested that stimulating the M1 region has a more pronounced analgesic effect. This discrepancy may be due to the smaller number of patients included in the M1 group in their experiment, as they only included 20 patients in the M1 group compared to the DLPFC group.…”

“…Further scrutiny of the full texts of the remaining 12 articles led to the exclusion of 7 more studies due to dates that could not be extracted ( n = 2), non-randomized control trials ( n = 3) and patient overlap ( n = 2). This process resulted in the selection of 5 randomized controlled trials for the analysis of the efficacy of rTMS in PHN ( 11 , 14 – 17 ). Figure 1 displays the PRISMA flow diagram depicting this selection process.…”

“…Repetitive transcranial magnetic stimulation (rTMS), as a non-invasive brain stimulation technique, has emerged as a promising intervention in the treatment of neuropathic pain ( 10 ). However, there is limited research on rTMS for treating PHN, and there is controversy over its effectiveness ( 11 – 16 ). The improvement of short-form McGill pain questionnaire (SF-MPQ) ( 11 , 14 , 15 , 17 ) and patients’ global impression of change scale (PGIC) ( 14 , 15 , 17 ) post-treatment is also a subject of debate.…”

“…However, there is limited research on rTMS for treating PHN, and there is controversy over its effectiveness ( 11 – 16 ). The improvement of short-form McGill pain questionnaire (SF-MPQ) ( 11 , 14 , 15 , 17 ) and patients’ global impression of change scale (PGIC) ( 14 , 15 , 17 ) post-treatment is also a subject of debate.…”

Transcranial Magnetic Stimulation to Treat Neuropathic Pain: A Bibliometric Analysis

“…The keywords less mentioned but with important link strengths were “neuralgia” and “treatment outcome”. This probably shows that some investigators devote their work to understanding the impact of using TMS on the treatment of neuropathic pain, evaluating the resulting outcomes and understanding the impact of using TMS in the treatment of different types of neuropathic pain, such as neuralgia [ 31 ]. In fact, there are studies that suggest that TMS is a reasonable and well-tolerated add-on treatment in neuropathic pain [ 32 , 33 , 34 , 35 ].…”