Long-Term Patient-Reported Outcome of Radiofrequency Thalamotomy for Tremor

Background: Thalamotomy is an endorsed treatment for medication-refractory tremor. It used to be the standard, but nowadays deep brain stimulation (DBS) has become the treatment option of choice. Nevertheless, DBS has the disadvantage of hardware failure, battery replacement, and frequent setting adjustment. Radiofrequency (RF) thalamotomy lacks these issues, is relatively inexpensive, and has a broad applicability in patients with significant comorbidity. Therefore, we analyzed the long-term patient-reported outcome of RF thalamotomy in a cohort of patients with an otherwise intractable tremor. Methods: A single-center cohort of 27 consecutive patients with intractable tremor was assessed after unilateral RF thalamotomy. Over time, 4 patients had died because of non-related causes. In total, 21 patients responded to a telephone survey to assess their personal judgment on postoperative tremor severity, using a validated tremor scale, adverse events, recurrence, and patient satisfaction. The median time between surgery and telephone survey was 39 months (range 12-126). Seven patients had an additional analysis with postoperative imaging, video-assisted electromyography tremor registration, and a self-reported treatment effect (SRTE) assessment. Results: Nineteen out of 21 patients (90.5%) reported absence or significant improvement of their tremor. The rating score (WHIGET/UPDRS-III) dropped significantly from a mean of 3.57 preoperatively to 1.05 postoperatively (p < 0.001). Eleven patients (52.4%) reported adverse events, but the majority (76.2%) did not consider the adverse events to be severe. SRTE assessment showed a direct postoperative effect of 89.6 of 100 points (SD 10.8), with a gradual decrease to 75.3 (SD 23.5) during follow-up. Conclusions: RF thalamotomy is a very effective long-term treatment for medication-refractory tremor and should therefore be considered in patients with a refractory unilateral tremor

Optimal Parameters of Deep Brain Stimulation in Essential Tremor:A Meta-Analysis and Novel Programming Strategy

The programming of deep brain stimulation (DBS) parameters for tremor is laborious and empirical. Despite extensive efforts, the end-result is often suboptimal. One reason for this is the poorly understood relationship between the stimulation parameters' voltage, pulse width, and frequency. In this study, we aim to improve DBS programming for essential tremor (ET) by exploring a new strategy. At first, the role of the individual DBS parameters in tremor control was characterized using a meta-analysis documenting all the available parameters and tremor outcomes. In our novel programming strategy, we applied 10 random combinations of stimulation parameters in eight ET-DBS patients with suboptimal tremor control. Tremor severity was assessed using accelerometers and immediate and sustained patient-reported outcomes (PRO's), including the occurrence of side-effects. The meta-analysis showed no substantial relationship between individual DBS parameters and tremor suppression. Nevertheless, with our novel programming strategy, a significantly improved (accelerometer p = 0.02, PRO p = 0.02) and sustained (p = 0.01) tremor suppression compared to baseline was achieved. Less side-effects were encountered compared to baseline. Our pilot data show that with this novel approach, tremor control can be improved in ET patients with suboptimal tremor control on DBS. In addition, this approach proved to have a beneficial effect on stimulation-related complications

Spinal Cord Ischemia Related to Disc Herniation:Case Report and a Review of the Literature

Symptoms of spinal cord ischemia can mimic myelopathy due to spinal cord compression in the acute phase. Thoracic disc herniation with limited spinal cord compression but rapid progression of neurological symptoms causes a clinical dilemma as to whether emergency decompression should be performed. We report a case of acute progressive myelopathy due to spinal cord ischemia related to thoracic disc herniation initially managed by Th8 laminectomy with reduction of the herniated disc. Repeat imaging showed T2-weighted hyperintensity in the posterior cord. The clinical and radiological course supports posterior spinal artery ischemia. This case illustrates and a review of the literature shows that thoracic disc herniation may be complicated by ischemic myelopathy even in the absence of cord compression

Bilateral Pallidotomy for Dystonia:A Systematic Review

Stereotactic lesioning of the bilateral globus pallidus (GPi) was one of the first surgical treatments for medication-refractory dystonia but has largely been abandoned in clinical practice after the introduction of deep brain stimulation (DBS). However, some patients with dystonia are not eligible for DBS. Therefore, we reviewed the efficacy, safety, and sustainability of bilateral pallidotomy by conducting a systematic review of individual patient data (IPD). Guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses and IPD were followed. In May 2020, Medline, Embase, Web of Science, and Cochrane Library were searched for studies reporting on outcome of bilateral pallidotomy for dystonia. If available, IPD were collected. In this systematic review, 100 patients from 33 articles were evaluated. Adverse events were reported in 20 patients (20%), of which 8 were permanent (8%). Pre-and postoperative Burke-Fahn-Marsden Dystonia Rating Movement Scale scores were available for 53 patients. A clinically relevant improvement (>20%) of this score was found in 42 of 53 patients (79%). Twenty-five patients with status dystonicus (SD) were described. In all but 2 the SD resolved after bilateral pallidotomy. Seven patients experienced a relapse of SD. Median-reported follow-up was 12 months (n = 83; range: 2-180 months). Based on the current literature, bilateral pallidotomy is an effective and relatively safe procedure for certain types of dystonia, particularly in medication-refractory SD. Although due to publication bias the underreporting of negative outcomes is very likely, bilateral pallidotomy is a reasonable alternative to DBS in selected dystonia patients. (c) 2020 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society

Are we on the right track in DBS surgery for dystonic head tremor?:Polymyography is a promising answer

The clinical benefit of Deep Brain Stimulation (DBS) is associated with electrode positioning accuracy. Intraoperative assessment of clinical effect is therefore key. Evaluating this clinical effect in patients with dystonic head tremor, as opposed to limb tremor, is challenging because the head is fixed in a stereotactic frame. To clinically assess head tremor during surgery, surface electromyography (EMG) electrodes were bilaterally applied to the sternocleidomastoid and cervical paraspinal muscles. This case shows that intraoperative polymyography is an easy and useful tool to assess the clinical effect of DBS electrode positioning

Accuracy Assessment of Pedicle and Lateral Mass Screw Insertion Assisted by Customized 3D-Printed Drill Guides:A Human Cadaver Study

BACKGROUND: Accurate cervical screw insertion is of paramount importance considering the risk of damage to adjacent vital structures. Recent research in 3-dimensional (3D) technology describes the advantage of patient-specific drill guides for accurate screw positioning, but consensus about the optimal guide design and the accuracy is lacking. OBJECTIVE: To find the optimal design and to evaluate the accuracy of individualized 3D-printed drill guides for lateral mass and pedicle screw placement in the cervical and upper thoracic spine. METHODS: Five Thiel-embalmed human cadavers were used for individualized drill-guide planning of 86 screw trajectories in the cervical and upper thoracic spine. Using 3D bone models reconstructed from acquired computed tomography scans, the drill guides were produced for both pedicle and lateral mass screw trajectories. During the study, the initial minimalistic design was refined, resulting in the advanced guide design. Screw trajectories were drilled and the realized trajectories were compared to the planned trajectories using 3D deviation analysis. RESULTS: The overall entry point and 3D angular accuracy were 0.76 +/- 0.52 mm and 3.22 +/- 2.34 degrees, respectively. Average measurements for the minimalistic guides were 1.20 mm for entry points, 5.61 degrees for the 3D angulation, 2.38 degrees for the 2D axial angulation, and 4.80 degrees for the 2D sagittal angulation. For the advanced guides, the respective measurements were 0.66 mm, 2.72 degrees, 1.26 degrees, and 2.12 degrees, respectively. CONCLUSION: The study ultimately resulted in an advanced guide design including caudally positioned hooks, crosslink support structure, and metal inlays. The novel advanced drill guide design yields excellent drilling accuracy

The Accuracy of Patient-Specific Spinal Drill Guides Is Non-Inferior to Computer-Assisted Surgery:The Results of a Split-Spine Randomized Controlled Trial

In recent years, patient-specific spinal drill guides (3DPGs) have gained widespread popularity. Several studies have shown that the accuracy of screw insertion with these guides is superior to that obtained using the freehand insertion technique, but there are no studies that make a comparison with computer-assisted surgery (CAS). The aim of this study was to determine whether the accuracy of insertion of spinal screws using 3DPGs is non-inferior to insertion via CAS. A randomized controlled split-spine study was performed in which 3DPG and CAS were randomly assigned to the left or right sides of the spines of patients undergoing fixation surgery. The 3D measured accuracy of screw insertion was the primary study outcome parameter. Sixty screws inserted in 10 patients who completed the study protocol were used for the non-inferiority analysis. The non-inferiority of 3DPG was demonstrated for entry-point accuracy, as the upper margin of the 95% CI (−1.01 mm–0.49 mm) for the difference between the means did not cross the predetermined non-inferiority margin of 1 mm (p < 0.05). We also demonstrated non-inferiority of 3D angular accuracy (p < 0.05), with a 95% CI for the true difference of −2.30◦–1.35◦, not crossing the predetermined non-inferiority margin of 3◦ (p < 0.05). The results of this randomized controlled trial (RCT) showed that 3DPGs provide a non-inferior alternative to CAS in terms of screw insertion accuracy and have considerable potential as a navigational technique in spinal fixation

Acute effects of adaptive Deep Brain Stimulation in Parkinson's disease

Background: Beta-based adaptive Deep Brain Stimulation (aDBS) is effective in Parkinson's disease (PD), when assessed in the immediate post-implantation phase. However, the potential benefits of aDBS in patients with electrodes chronically implanted, in whom changes due to the microlesion effect have disappeared, are yet to be assessed. Methods: To determine the acute effectiveness and side-effect profile of aDBS in PD compared to conventional continuous DBS (cDBS) and no stimulation (NoStim), years after DBS implantation, 13 PD patients undergoing battery replacement were pseudo-randomised in a crossover fashion, into three conditions (NoStim, aDBS or cDBS), with a 2-min interval between them. Patient videos were blindly evaluated using a short version of the Unified Parkinson's Disease Rating Scale (subUPDRS), and the Speech Intelligibility Test (SIT). Results: Mean disease duration was 16 years, and the mean time since DBS-implantation was 6.9 years. subUPDRS scores (11 patients tested) were significantly lower both in aDBS (p=<.001), and cDBS (p = .001), when compared to NoStim. Bradykinesia subscores were significantly lower in aDBS (p = .002), and did not achieve significance during cDBS (p = .08), when compared to NoStim. Two patients demonstrated re-emerging tremor during aDBS. SIT scores of patients who presented stimulation-induced dysarthria significantly worsened in cDBS (p = .009), but not in aDBS (p = .407), when compared to NoStim. Overall, stimulation was applied 48.8% of the time during aDBS. Conclusion: Beta-based aDBS is effective in PD patients with bradykinetic phenotypes, delivers less stimulation than cDBS, and potentially has a more favourable speech side-effect profile. Patients with prominent tremor may require a modified adaptive strategy