Neurostimulation Devices for the Treatment of Neurologic Disorders.

Rapid advancements in neurostimulation technologies are providing relief to an unprecedented number of patients affected by debilitating neurologic and psychiatric disorders. Neurostimulation therapies include invasive and noninvasive approaches that involve the application of electrical stimulation to drive neural function within a circuit. This review focuses on established invasive electrical stimulation systems used clinically to induce therapeutic neuromodulation of dysfunctional neural circuitry. These implantable neurostimulation systems target specific deep subcortical, cortical, spinal, cranial, and peripheral nerve structures to modulate neuronal activity, providing therapeutic effects for a myriad of neuropsychiatric disorders. Recent advances in neurotechnologies and neuroimaging, along with an increased understanding of neurocircuitry, are factors contributing to the rapid rise in the use of neurostimulation therapies to treat an increasingly wide range of neurologic and psychiatric disorders. Electrical stimulation technologies are evolving after remaining fairly stagnant for the past 30 years, moving toward potential closed-loop therapeutic control systems with the ability to deliver stimulation with higher spatial resolution to provide continuous customized neuromodulation for optimal clinical outcomes. Even so, there is still much to be learned about disease pathogenesis of these neurodegenerative and psychiatric disorders and the latent mechanisms of neurostimulation that provide therapeutic relief. This review provides an overview of the increasingly common stimulation systems, their clinical indications, and enabling technologies.

Trial Design and Endpoint Evaluation in Clinical Studies Addressing Chronic Back Pain.

STUDY DESIGN: A review of the literature evaluating clinical trials of chronic back pain. OBJECTIVE: To assist physicians in assessing the quality of clinical trial data to make the most informed treatment decisions. SUMMARY OF BACKGROUND DATA: Chronic pain is a tremendous public health issue, affecting close to 100 million adults in the United States, and costs the American people billions of dollars. One traditional treatment approach, the long-term use of opiate medications, has recently come under intense scrutiny for problems with complications, diversion, abuse, addiction, and lack of efficacy. In addition, the Centers for Disease Control and Prevention has recognized that overprescribing opiates has enabled an overdose crisis, and written guidelines that are intended to limit their use. It is for this reason that physicians must have a comprehensive understanding of the range of drug-free alternative therapies available and have the tools needed to rigorously evaluate the chronic pain literature so they can make appropriate treatment decisions. METHODS: An evaluation of how clinical trials are designed and ranked, outcome measures, and costs for a variety of therapies is necessary to determine which treatment option is the most efficacious for an individual patient. RESULTS: Clinical trial data demonstrate that spinal cord stimulation (SCS) is a safe and effective treatment option for many types of chronic pain, including back pain. The last 10 years has brought tremendous advances in the field of neuromodulation. Today, several treatment modalities exist for SCS requiring the physician to be able to critically evaluate and interpret the literature and determine which modality has the strongest evidence. When evaluating clinical trial data of patients with chronic back pain, emphasis must be placed on well designed, randomized controlled trials with long-term follow-up producing level I evidence. These data are obtained in a rigorous manner and are likely to have less bias when compared with lower level studies. CONCLUSION: The level I studies performed to date have provided evidence that treatment with SCS results in sustainable pain reduction and improvements in scores measuring quality of life and patient functioning in those patients with chronic intractable back pain. LEVEL OF EVIDENCE: 5.

Novel 10-kHz High-frequency Therapy (HF10 Therapy) Is Superior to Traditional Low-frequency Spinal Cord Stimulation for the Treatment of Chronic Back and Leg Pain: The SENZA-RCT Randomized Controlled Trial.

BACKGROUND: Current treatments for chronic pain have limited effectiveness and commonly known side effects. Given the prevalence and burden of intractable pain, additional therapeutic approaches are desired. Spinal cord stimulation (SCS) delivered at 10 kHz (as in HF10 therapy) may provide pain relief without the paresthesias typical of traditional low-frequency SCS. The objective of this randomized, parallel-arm, noninferiority study was to compare long-term safety and efficacy of SCS therapies in patients with back and leg pain. METHODS: A total of 198 subjects with both back and leg pain were randomized in a 1:1 ratio to a treatment group across 10 comprehensive pain treatment centers. Of these, 171 passed a temporary trial and were implanted with an SCS system. Responders (the primary outcome) were defined as having 50% or greater back pain reduction with no stimulation-related neurological deficit. RESULTS: At 3 months, 84.5% of implanted HF10 therapy subjects were responders for back pain and 83.1% for leg pain, and 43.8% of traditional SCS subjects were responders for back pain and 55.5% for leg pain (P < 0.001 for both back and leg pain comparisons). The relative ratio for responders was 1.9 (95% CI, 1.4 to 2.5) for back pain and 1.5 (95% CI, 1.2 to 1.9) for leg pain. The superiority of HF10 therapy over traditional SCS for leg and back pain was sustained through 12 months (P < 0.001). HF10 therapy subjects did not experience paresthesias. CONCLUSION: HF10 therapy promises to substantially impact the management of back and leg pain with broad applicability to patients, physicians, and payers.