Deep brain stimulation: indications and evidence

Abstract

Deep brain stimulation is a minimally invasive targeted neurosurgical intervention that enables structures deep in the brain to be stimulated electrically by an implanted pacemaker. It has become the treatment of choice for Parkinson's disease, refractory to, or complicated by, drug therapy. Its efficacy has been demonstrated robustly by randomized, controlled clinical trials, with multiple novel brain targets having been discovered in the last 20 years. Multifarious clinical indications for deep brain stimulation now exist, including dystonia and tremor in movement disorders; depression, obsessive-compulsive disorder and Tourette's syndrome in psychiatry; epilepsy, cluster headache and chronic pain, including pain from stroke, amputation, trigeminal neuralgia and multiple sclerosis. Current research argues for novel indications, including hypertension and orthostatic hypotension. The development, principles, indications and effectiveness of the technique are reviewed here. While deep brain stimulation is a standard and widely accepted treatment for Parkinson's disease after 20 years of experience, in chronic pain it remains restricted to a handful of experienced, specialist centers willing to publish outcomes despite its use for over 50 years. Reasons are reviewed and novel approaches to appraising clinical evidence in functional neurosurgery are suggested.

Nociception and autonomic nervous system

“…The stimulation of this structure may provide long-term effective pain relief in selected patients [52,53]. The PAG receives afferents from the central and from the peripheral nervous systems.…”

Predictors of unfavorable outcomes following deep brain stimulation for movement disorders and the effect of hospital case volume on outcomes: an analysis of 33, 642 patients across 234 US hospitals using the National (Nationwide) Inpatient Sample from 2002 to 2011

“…DBS is now used to treat dystonia, essential tremor, obsessive-compulsive disorder, Tourette's syndrome, epilepsy, cluster headaches, stroke-related pain, phantom-limb pain, trigeminal neuralgia, and multiple sclerosis. 4,21,29,35 When DBS gained government-regulated approval, an increase in the national number of DBS procedures was noted. In 1996, 756 DBS procedures were performed, which increased to 4200 DBS procedures by 2006.…”

Neuropathic Pain and Deep Brain Stimulation

“…Another method favored for evaluating analgesia in single cases and small groups of patients is the N-of-1 trial [135][136][137]. A randomized, placebo-controlled intrapatient trial is conducted whereby the patient receives pairs of treatment periods during which each intervention-be it DBS on or off, or different stimulation targets or parameters-occurs once.…”