Deep Brain Stimulation Surgery (DBS) in refractory Chronic Pain

IntroductionAlthough DBS has been FDA approved for a number of indications (Parkinson, Dystonia, Tremor,etc.) but it still considered an off-label option when used to treat refractory pain.There is still a need for definitive randomized clinical trials to provide clear evidence-based proof of the safety and efficacy of DBS in refractory painHistorically, several neuromodulatory pain targets have been investigated, beginning in the 1950s. The periaqueductal/periventricular gray regions (PAG/PVG) in the midbrain and ventrocaudal nucleus (Vc) of the sensory thalamus have emerged as the two most common contemporary targets aimed at alleviating pain of nociceptive and neuropathic origin, respectively. Other less-studied DBS targets for chronic pain include the centromedian/parafascicular region (CM-Pf) of the thalamus, the internal capsule, and the posterior hypothalamus for cluster headache. Recently, anterior cingulate cortex (A C C) in patients withchronic neuropathic pain and ventral capsule/ventral striatum area selected for DBS in chronic pain management. Patient Selection and Indications:Patient selection should be done by an experienced multidisciplinary team of clinicians, including a psychiatrist, neurosurgeon, neuropsychologist, and pain specialist,Limitations:Conventional contraindications for DBS, including uncorrectable coagulation disorders, dementia, pregnancy, and inability to undergo an MRI, also apply to surgery for chronic pain. In addition, neurotic and uncooperative patients are poor candidates for techniques that require a patient’s subjective judgment for perioperative assessment and intraoperative complianceAssessment:Pain must be evaluated from both quantitative and qualitative perspectives by expert staff.Visual analogue scores (VAS) for reporting pain may not fully reflect clinical improvement in function and quality of life. Evaluation also must include short-form 36-question quality-of-life survey (SF-36), McGill pain questionnaire, and EuroQol-5D questionnaires.