Pilitsis, Julie G.

Since its US Food and Drug Administration approval in 2016, magnetic resonance–guided focused ultrasound (MRgFUS) thalamotomy has grown into one of the procedures of choice among patients with essential tremor (ET). Approved applications for the procedure have expanded over time from unilateral thalamotomy to treat ET and Parkinson disease tremor to bilateral staged thalamotomy for ET. As the procedure expands to healthcare environments beyond large academic centers, guidance is required to ensure that the responsible clinicians are appropriately trained to undertake this operative procedure. Although multidisciplinary movement disorder teams are important for the optimal management of patients, MRgFUS lesions are inherently surgical interventions. Neurosurgeons are trained to evaluate these patients, consider surgical alternatives and conduct these operations, particularly after completing a fellowship in the subspecialty of stereotactic and functional neurosurgery. At present, all high-level evidence regarding the safety and efficacy of MRgFUS lesions to treat movement disorders derives from procedures performed by neurosurgeons, so those results may not be generalizable to other physicians. Based on these considerations and potential liability issues, the American Society for Stereotactic and Functional Neurosurgery, which acts as the joint section representing the field of stereotactic and functional neurosurgery on behalf of the Congress of Neurological Surgeons and the American Association of Neurological Surgeons, puts forth this position statement that only neurosurgeons appropriately trained to conduct functional neurosurgery procedures should conduct MRgFUS surgical lesions.

OBJECTIVE Magnetic resonance–guided focused ultrasound (MRgFUS) thalamotomy has become a popular tool in the neurosurgical armamentarium for managing tremor in patients with essential tremor (ET) and Parkinson’s disease (PD). METHODS Given the recent exponential growth in the use of this technology, the American Society for Stereotactic and Functional Neurosurgery, which acts as the joint section representing the field of stereotactic and functional neurosurgery on behalf of the Congress of Neurological Surgeons and the American Association of Neurological Surgeons, provides an update on treatment indications and the efficacy and safety of MRgFUS for the treatment of tremor. RESULTS In ET, the efficacy of MRgFUS thalamotomy is supported by several open-label and 1 prospective, double-blind, sham-controlled randomized clinical trial (RCT) that showed a 47% improvement in hand tremor in the short term. Follow-up studies demonstrated that the benefits of MRgFUS for ET are sustained in the long term. Studies investigating the effects of bilateral staged MRgFUS thalamotomy in patients with ET have shown that tremor improvement on the second side was as significant as that observed after the first procedure. The efficacy of MRgFUS thalamotomy for PD tremor is supported by a systematic meta-analysis that consisted predominantly of smaller, nonrandomized studies; 1 RCT; and 1 prospective cohort study. Despite a significant short-term improvement in PD tremor, the long-term effects of this therapy remain unknown. Common early adverse effects of MRgFUS thalamotomy include gait disturbance and paresthesias. These, however, tend to subside over time. Other reported side effects are dysarthria, ataxia, taste disturbance, motor deficits, and speech difficulty. CONCLUSIONS MRgFUS thalamotomy is a safe, effective, and durable intervention for refractory ET in appropriately selected patients. The procedure appears to be safe and effective for PD tremor, although the long-term durability of the technique remains a concern. Early experience with bilateral staged lesions for ET suggests the procedure to be safe and effective.

Background The efficacy of EVOKE therapy, a closed-loop spinal cord stimulation (SCS) system, has been demonstrated in a double-blinded randomized controlled trial (RCT). RCT evidence, however, may not be generalizable to clinical practice, while limitations of real-world evidence may affect its validity. The aim of this study was to evaluate the effectiveness of EVOKE therapy in routine clinical practice employing a rigorous data collection approach. Methods The ECAP study was a prospective, multicenter, single-arm, pragmatic study that enrolled SCS candidates with chronic, intractable trunk and/or limb pain in 22 US investigational sites. PROMIS-29 questionnaire and objective neurophysiological metrics were collected, and minimal clinically important differences (MCIDs) were used to characterize baseline dysfunction and response to EVOKE therapy both at trial end and maximal analgesic effect post-implant visit. Pre-specified subgroup analyses were conducted based on diagnosis. Results EVOKE therapy observed included a dose ratio of 1.3 and neural dose accuracy of 2.8 μV. Improvements of >1 MCID were observed for all domains and improvements of ≥2 MCIDs were observed for six of the seven domains. Improvements observed at trial end were maintained or improved at post-implant visit, with statistically significant improvement in holistic MCID (MD 0.2, 95% CI 0.1 to 0.4, p=0.004), and a significantly greater proportion of patients considered holistic MCID responders (p=0.047). Subgroup analysis by diagnosis showed similar outcomes. Conclusions EVOKE therapy was associated with clinically meaningful improvements in a real-world chronic pain population across different subgroups and disease pathologies, with effects observed at trial end reproduced at post-implant visit.

Importance The Implantable Neurostimulator for the Treatment of Parkinson’s Disease (INTREPID) trial was a randomized, double-blind, sham-controlled study of subthalamic nucleus (STN) deep brain stimulation (DBS) for the treatment of Parkinson disease (PD). Objective To evaluate the long-term (5-year) outcomes and safety of STN-DBS for PD. Design, Setting, and Participants This was a prospective, randomized (3:1), 12-week double-blind sham-controlled study at 23 movement disorder centers across the US with an open-label 5-year follow-up. Patients were implanted and followed up with the Vercise DBS system from May 2013 to December 2022. Eligibility required diagnosis of bilateral idiopathic PD with more than 5 years of motor symptoms, more than 6 hours per day of poor motor function, modified Hoehn and Yahr Scale scores higher than 2, Unified Parkinson’s Disease Rating Scale (UPDRS-III) score of 30 or higher (medication-off state), and 33% or higher improvement in UPDRS-III medication-on score. Intervention Bilateral STN-DBS for moderate to advanced PD. Main Outcomes and Measures Primary outcomes included changes in UPDRS and dyskinesia scores, quality-of-life measures, and safety assessments. Exploratory analyses included medication reduction and DBS association with motor signs. Results A total of 313 patients were enrolled with 191 receiving the DBS system, and 137 participants (72%) completed the study. The study population had a mean (SD) age of 60 (7.9) years, with 139 (73%) male participants. Motor function without medication as measured by UPDRS-III improved from a mean (SD) of 42.8 (9.4) to 21.1 (10.6) at year 1 (51%; 95% CI, 49%-53%; P < .001) and 27.6 (11.6) at year 5 (36%; 95% CI, 33%-38%; P < .001). Activities of daily living without medication as measured by UPDRS-II improved from a mean (SD) of 20.6 (6.0) to 12.4 (6.1) at year 1 (41%; 95% CI, 38%-42%; P < .001) and 16.4 (6.5) at year 5 (22%; 95% CI, 18%-23%; P < .001). Dyskinesia scores decreased from 4.0 (5.1) to 1.0 (2.1) at year 1 (75%; 95% CI, 73%-75%; P < .001) and to 1.2 (2.1) at year 5 (70%; 95% CI, 63%-75%; P < .001). The levodopa equivalent dose was reduced by 28% at year 1, remaining stable at year 5 (28%; 95% CI, 26%-31%; P < .001). The most common serious adverse event was infection (9 participants). Ten deaths were reported, none related to the study. Conclusions and Relevance Although STN-DBS outcomes declined slightly, possibly due to the progressive nature of the disease, patients with PD sustained significant improvement in motor and activities of daily living scores, along with a stable reduction in anti-parkinsonian medication over the 5-year follow-up period.

Abstract Introduction DISTINCT is a randomized controlled trial evaluating passive recharge burst SCS compared with CMM in improving pain and pain‐related physical function in patients suffering from chronic back pain without prior lumbar surgery, and for whom corrective surgery is not an option. Sub‐analyses of outcome measures are presented for a subset implanted with paddle leads at both 6 and 12 months. Objective To investigate the treatment effect of using BurstDR‐capable SCS in nonsurgical low back pain (NSLBP) patients with paddle leads. Methods An independent board‐certified spine surgeon reviewed each case, confirming a lack of corrective surgical options. Out of 29 sites and 115 implants, 10 sites implanted 50 patients with paddle leads. Primary and secondary endpoints assessed improvements in low back pain intensity (NRS), low back pain‐related disability (ODI), pain catastrophizing (PCS), and patient global impression of change (PGIC). Results Data for patients with NSLBP and implanted with paddle leads are available for 47 and 44 patients at 6 and 12 months, respectively. Patients reported significant reductions in pain relief at 6 and 12 months, decreasing from 7.8 ± 1.2 at baseline to 2.0 ± 1.6 and 2.2 ± 2.2, respectively ( p < 0.0001). Disability was substantially reduced (> 20 points) from severe to mild at 6 and 12 months; ODI reduced from 54.4 ± 15.0 at baseline to 19.9 ± 14.1 and 22.1 ± 13.6, respectively ( p < 0.0001). Pain catastrophizing improved to reflect the average of a non‐chronic pain population; decreased from 27.6 ± 13.1 at baseline to 8.1 ± 8.2 and 7.8 ± 9.9 ( p < 0.0001). 93.2% of patients reported a moderately better‐much‐improved outcome on PGIC. Ten complications occurred in 9 patients, 3 being severe device‐related events. Two explants were required; one due to infection and one due to persistent pain at the IPG site, and one lead‐related event was resolved by surgical repositioning. Conclusions Passive recharge burst using paddle leads provides substantial relief to patients suffering from severe, debilitating, NSLBP. Patients report significant improvements in pain, function, and pain‐related emotional distress. In addition, the rate of adverse events is low, supporting a favorable safety profile.

Background To provide recommendations on risk mitigation, diagnosis and treatment of infectious complications associated with the practice of regional anesthesia, acute and chronic pain management. Methods Following board approval, in 2020 the American Society of Regional Anesthesia and Pain Medicine (ASRA Pain Medicine) commissioned evidence-based guidelines for best practices for infection control. More than 80 research questions were developed and literature searches undertaken by assigned working groups comprising four to five members. Modified US Preventive Services Task Force criteria were used to determine levels of evidence and certainty. Using a modified Delphi method, >50% agreement was needed to accept a recommendation for author review, and >75% agreement for a recommendation to be accepted. The ASRA Pain Medicine Board of Directors reviewed and approved the final guidelines. Results After documenting the incidence and infectious complications associated with regional anesthesia and interventional pain procedures including implanted devices, we made recommendations regarding the role of the anesthesiologist and pain physician in infection control, preoperative patient risk factors and management, sterile technique, equipment use and maintenance, healthcare setting (office, hospital, operating room), surgical technique, postoperative risk reduction, and infection symptoms, diagnosis, and treatment. Consensus recommendations were based on risks associated with different settings and procedures, and keeping in mind each patient’s unique characteristics. Conclusions The recommendations are intended to be multidisciplinary guidelines for clinical care and clinical decision-making in the regional anesthesia and chronic interventional pain practice. The issues addressed are constantly evolving, therefore, consistent updating will be required.

OBJECTIVE The objective of this study was to evaluate the 24-month durability of pain relief, function, quality of life, and safety outcomes for patients with nonsurgical refractory back pain (NSRBP) treated with high-frequency spinal cord stimulation (SCS) within a large, national, multicenter randomized controlled trial (RCT). METHODS Following the completion of an RCT comparing high-frequency SCS plus CMM with CMM alone for the treatment of NSRBP, patients gave additional consent for a follow-up extension to 24 months. Presented is the cohort analysis of all patients treated with high-frequency SCS following the optional crossover at 6 months. The outcomes assessed to 24 months included responder rate of ≥ 50% pain relief measured according to the visual analog scale [VAS]), disability (Oswestry Disability Index [ODI]), quality of life (EQ-5D 5-level [EQ-5D-5L]), opioid reduction. RESULTS Of the 125 patients who received a permanent implant, 121 completed the 12-month follow-up, 101 gave additional consent for extended follow-up, and 98 completed the 24-month follow-up. At 24 months after implantation, the mean back pain VAS score was reduced by 73% and the responder rate was 82%. ODI and EQ-5D-5L both improved by at least double the minimal clinically important difference for each measure. No unexpected adverse events were observed, and the rates of serious adverse events (3.4%) and device explantations (4.8%) were low. CONCLUSIONS The addition of high-frequency SCS to CMM in patients with NSRBP offers profound improvements at 24 months in pain, function, quality of life, and reduced opioid use. This study provides much-needed evidence to inform current clinical practice for managing patients with NSRBP.

OBJECTIVE Spinal cord stimulation (SCS) at 10 kHz (10-kHz SCS) is a safe and effective therapy for treatment of chronic low-back pain. However, it is unclear from existing evidence whether these findings can be generalized to patients with chronic back pain that is refractory to conventional medical management (CMM) and who have no history of spine surgery and are not acceptable candidates for spine surgery. The authors have termed this condition "nonsurgical refractory back pain" (NSRBP) and conducted a multicenter, randomized controlled trial to compare CMM with and without 10-kHz SCS in this population. METHODS Patients with NSRBP, as defined above and with a spine surgeon consultation required for confirmation, were randomized 1:1 to patients undergoing CMM with and without 10-kHz SCS. CMM included nonsurgical treatment for back pain, according to physicians’ best practices and clinical guidelines. Primary and secondary endpoints included the responder rate (≥ 50% pain relief), disability (Oswestry Disability Index [ODI]), global impression of change, quality of life (EQ-5D-5L), and change in daily opioid use and were analyzed 3 and 6 months after randomization. The protocol allowed for an optional crossover at 6 months for both arms, with observational follow-up over 12 months. RESULTS In total, 159 patients were randomized; 76 received CMM, and 69 (83.1%) of the 83 patients who were assigned to the 10-kHz SCS group received a permanent implant. At the 3-month follow-up, 80.9% of patients who received stimulation and 1.3% of those who received CMM were found to be study responders (primary outcome, ≥ 50% pain relief; p < 0.001). There was also a significant difference between the treatment groups in all secondary outcomes at 6 months (p < 0.001). In the 10-kHz SCS arm, outcomes were sustained, including a mean 10-cm visual analog scale score of 2.1 ± 2.3 and 2.1 ± 2.2 and mean ODI score of 24.1 ± 16.1 and 24.0 ± 17.0 at 6 and 12 months, respectively (p = 0.9). In the CMM arm, 74.7% (56/75) of patients met the criteria for crossover and received an implant. The crossover arm obtained a 78.2% responder rate 6 months postimplantation. Five serious adverse events occurred (procedure-related, of 125 total permanent implants), all of which resolved without sequelae. CONCLUSIONS The study results, which included follow-up over 12 months, provide important insights into the durability of 10-kHz SCS therapy with respect to chronic refractory back pain, physical function, quality of life, and opioid use, informing the current clinical practice for pain management in patients with NSRBP.

AbstractBackgroundSpinal cord stimulation (SCS) has been shown to provide pain relief for chronic back and leg pain due to failed back surgery syndrome. But many patients with chronic back pain have not had major back surgery or are not good candidates for surgery, and conventional medical management (CMM) provides limited relief. We have termed this condition nonsurgical refractory back pain (NSRBP). Level 1 evidence does not yet exist showing the therapeutic benefit of SCS for NSRBP.ObjectiveTo compare 10‐kHz SCS plus CMM (10‐kHz SCS + CMM) to CMM alone for treatment of NSRBP in terms of clinical and cost effectiveness.Study DesignMulticenter, randomized controlled trial (RCT), with subjects randomized 1:1 to either 10‐kHz SCS + CMM or CMM alone. Optional crossover occurs at 6 months if treatment does not achieve ≥50% pain relief.MethodsPatients with NSRBP as defined above may be enrolled if they are ineligible for surgery based on surgical consultation. Subjects randomized to 10‐kHz SCS + CMM will receive a permanent implant if sufficient pain relief is achieved in a temporary trial. Both groups will receive CMM per standard of care and will undergo assessments at baseline and at follow‐ups to 12 months. Self‐report outcomes include pain, disability, sleep, mental health, satisfaction, healthcare utilization, and quality of life.ResultsEnrollment was initiated on September 10, 2018. Prespecified independent interim analysis at 40% of the enrollment target indicated the sample size was sufficient to show superiority of treatment at the primary endpoint; therefore, enrollment was stopped at 211.ConclusionsThis large multicenter RCT will provide valuable evidence to guide clinical decisions in NSRBP.