Deep Brain Stimulation for Facial Pain.

Electro-modulation of subcortical deep brain structures by surgically implanted electrodes is now standard evidence-based treatment for movement disorders such as Parkinson's disease and essential tremor and is approved for dystonia and obsessive-compulsive disorder under a humanitarian exemption. Historically, deep brain stimulation (DBS) for multiple indications has demonstrated acceptable complication rates, rare mortality, and reducing morbidity as the technology and the techniques of its application have advanced. DBS for the amelioration of pain has been performed since the early 1950s, and became widely used in the 1970s, when targeting the somatosensory thalamus was shown to be efficacious for intractable pain syndromes including facial pain. The technique fell out of favour in the late 1990s after 2 multicentre trials failed to meet end-point criteria. Since these trials, DBS for pain has remained for investigational or "off-label" use. Criticisms from previous literature have involved unsuitability of patient selection, as well as inconsistencies in neurosurgical technique. Clinical success with DBS for facial pain has been for the treatment of a variety of chronic neuropathic and nociceptive pain syndromes; including trigeminal neuropathy, post-herpetic neuralgia, deafferentation facial pain, "atypical" facial pain, cluster headaches and other trigeminal autonomic cephalalgias, as well as head and neck pathologies, most often which have been resistant to all other 1st- and 2nd-line medical and surgical treatments, when DBS has become a "last treatment option." An enhanced understanding of the mechanisms of action of DBS for pain will enhance outcome, and appropriately prescribe evolving novel nuclear brain targets.