Invasive Neuromodulation of the Central Nervous System in Painful Trigeminal Neuropathy: A Systematic Review

Motor cortex stimulation (MCS), deep brain stimulation (DBS), and spinal cord stimulation (SCS) are invasive neuromodulatory techniques that can be trialed in medically and/or surgically refractory painful trigeminal neuropathy. We aimed to assess the outcomes of MCS, DBS, and SCS in the treatment of painful trigeminal neuropathy.

MEDLINE, Embase, and Cochrane Library electronic databases were searched from inception to April 2021 following Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines. The search was rerun in April 2024. Studies were included if they reported on adults diagnosed with painful trigeminal neuropathy who underwent MCS, DBS, or SCS. The primary outcome was reduction in patient-reported pain intensity. Secondary outcomes included adverse effects. Risk of bias and study quality were assessed.

Overall, 21 articles satisfied all inclusion criteria (13 MCS, five DBS, three SCS). Data were obtained for a total of 187 patients. Included diagnoses were painful trigeminal neuropathy attributed to herpes zoster, trigeminal postherpetic neuralgia, painful posttraumatic trigeminal neuropathy, painful trigeminal neuropathy attributed to other disorder, and idiopathic painful trigeminal neuropathy. Significant pain reductions were obtained with all three techniques, and some subtypes of painful trigeminal neuropathy appeared to benefit most from DBS and SCS. MCS and DBS reduced pain in painful trigeminal neuropathy, and posterior hypothalamus DBS was effective in patients with multiple sclerosis-associated pain in the V1 distribution. SCS indicated mixed results but was most effective for nondeafferentation pain. There was bias present in the one controlled trial of MCS and low-quality evidence among the remaining studies.

There is promising but limited, low-quality evidence to support the use of MCS, DBS, and SCS in painful trigeminal neuropathy. Additional research is required to strengthen the evidence, improve patient selection, and determine optimal stimulation settings for the diverse range of painful trigeminal neuropathies.