Systematic Review and Meta-Analysis of High-Frequency rTMS over the Dorsolateral Prefrontal Cortex .on Chronic Pain and Chronic-Pain-Accompanied Depression

The effect of high-frequency (HF) repetitive transcranial magnetic stimulation (rTMS) on the dorsolateral prefrontal cortex (DLPFC) can relieve chronic pain and accompanying depressive symptoms. However, in recent years, some high-quality studies have challenged this view. Therefore, it is necessary to update the data and analyze the effects of HF rTMS on the DLPFC on chronic pain and accompanying depression. We performed a systematic review and meta-analysis to evaluate the effect of HF rTMS on the DLPFC on chronic pain and accompanying depression. We searched PubMed, Medline, Web of Science, and Cochrane through September 2021. The search strings searched were : "pain" AND ("TMS" OR "transcranial magnetic stimulation") AND "prefrontal cortex". The inclusion criteria according to PICOS was as follows: P, patient with chronic pain; I, HF (≥5 Hz) rTMS on the DLPFC; C, included a sham treatment condition; O, pain indicators; S, pre-/poststudies, crossover, or parallel-group. We extracted the pain and accompanying depression evaluation indicators. The short-term analgesic effect of HF rTMS over the left DLPFC is not significant (WMD = 0.34, 95% CI: [−1.60, 2.28]) but has a significant mid-term and long-term analgesic effect on chronic pain (WMD = −0.50, 95% CI: [−0.99, −0.01]; WMD = −1.10, 95% CI: [−2.00, −0.19], respectively). HF rTMS over the DLPFC can effectively alleviate the depressive symptoms of patients with chronic pain (WMD = −0.83, 95% CI: [−3.01, 1.36]). Thus, HF rTMS on the left DLPFC can relieve chronic pain and accompanying depressive symptoms.