D.L. Marinus Oterdoom

Bilateral versus unilateral interlaminar approach for bilateral decompression in patients with single-level degenerative lumbar spinal stenosis : a multicenter retrospective study of 175 patients on postoperative pain, functional disability, and patient satisfaction

OBJECT The bilateral and unilateral interlaminar techniques for bilateral decompression both demonstrate good results for the treatment of degenerative lumbar spinal stenosis (DLSS). Although there is some discussion about which approach is more effective, studies that directly compare these two popular techniques are rare. To address this shortcoming, this study compares postoperative functional disability, pain, and patient satisfaction among patients with single-level DLSS who underwent bilateral decompression using either a bilateral or unilateral approach. METHODS This retrospective study included patients who underwent operations between November 1, 2009, and October 1, 2011. These patients underwent single-level bilateral decompressive surgery using either the bilateral or unilateral interlaminar approach at one of 5 participating hospitals. Exclusion criteria included previous lumbar surgery, additional disc surgery, and spondylolisthesis requiring fusion surgery. Primary outcome measures included bodily pain (as reported using the visual analog scale [VAS]), the Roland-Morris Disability Questionnaire (RMDQ), and the Oswestry Disability Index (ODI). In addition, reductions in leg and back symptoms and the patients general evaluation of the procedure were queried. Finally, patient satisfaction and surgical parameters were evaluated. Questionnaires were sent to each patients home, and electronic patient files were used to collect the data. RESULTS One hundred and seventy-five patients returned the questionnaire (74.4% response rate; 68 and 107 patients who underwent the bilateral or unilateral approach, respectively). Mean age at surgery was 68 years (range 34-89 years), and the mean follow-up period was 14.2 months (range 3.3-27.4 years). There were no significant differences in ODI (20.3 vs 22.6 for the bilateral and unilateral approaches, respectively), RMDQ (3.99 vs 4.8, respectively), or pain scores between treatment groups. Back symptoms were reduced in 74.8% (bilateral: 74.6% vs unilateral: 75%; not significant), and leg symptoms in 80.6% of the patients (bilateral: 73.1% vs unilateral: 85.4%; p = 0.048). In total, 72.1% (bilateral) and 80.0% (unilateral) of patients reported good overall treatment results (p = 0.226). Significantly more patients in the unilateral group reported a better overall satisfaction with the procedure (82.1% vs 69.1%; p = 0.047). CONCLUSIONS There were no differences in postoperative functional disability and pain between the surgical techniques. The significant differences in patient satisfaction and reduction in leg symptoms were unrelated to surgical technique. The overall treatment results were satisfactory. Both techniques are safe and effective options for treating patients with single-level DLSS.

Dystonia‐deafness syndrome caused by a β‐actin gene mutation and response to deep brain stimulation

Dystonia‐deafness syndrome is a distinct clinical presentation within the dystonia‐spectrum. Although several genetic and acquired causes have been reported, etiology remains unknown in the majority of patients.

Surgical Accuracy of 3-Tesla Versus 7-Tesla Magnetic Resonance Imaging in Deep Brain Stimulation for Parkinson Disease

BACKGROUND In deep brain stimulation (DBS), accurate placement of the lead is critical. Target definition is highly dependent on visual recognition on magnetic resonance imaging (MRI). We prospectively investigated whether the 7-T MRI enabled better visualization of targets and led to better placement of leads compared with the 1.5-T and the 3-T MRI. METHODS Three patients with PD (mean, 55 years) were scanned on 1.5-, 3-, and 7-T MRI before surgery. Tissue contrast and signal-to-noise ratio were measured. Target coordinates were noted on MRI and during surgery. Differences were analyzed with post-hoc analysis of variance. RESULTS The 7-T MRI demonstrated a significant improvement in tissue visualization (P < 0.005) and signal-to-noise ratio (P < 0.005). However, no difference in the target coordinates was found between the 7-T and the 3-T MRI. CONCLUSIONS Although the 7-T MRI enables a significant better visualization of the DBS target in patients with PD, we found no clinical benefit for the placement of the DBS leads.

Toward adaptive deep brain stimulation for dystonia

The presence of abnormal neural oscillations within the cortico-basal ganglia-thalamo-cortical (CBGTC) network has emerged as one of the current principal theories to explain the pathophysiology of movement disorders. In theory, these oscillations can be used as biomarkers and thereby serve as a feedback signal to control the delivery of deep brain stimulation (DBS). This new form of DBS, dependent on different characteristics of pathological oscillations, is called adaptive DBS (aDBS), and it has already been applied in patients with Parkinsons disease. In this review, the authors summarize the scientific research to date on pathological oscillations in dystonia and address potential biomarkers that might be used as a feedback signal for controlling aDBS in patients with dystonia.

The characteristics of pallidal low-frequency and beta bursts could help implementing adaptive brain stimulation in the parkinsonian and dystonic internal globus pallidus

INTRODUCTION Adaptive deep brain stimulation (aDBS) has been applied in Parkinsons disease (PD), based on the presence of brief high-amplitude beta (13-35 Hz) oscillation bursts in the subthalamic nucleus (STN), which correlate with symptom severity. Analogously, average low-frequency (LF) oscillatory power (4-12 Hz) in the internal globus pallidus (GPi) correlates with dystonic symptoms and might be a suitable physiomarker for aDBS in dystonia. Characterization of pallidal bursts could facilitate the implementation of aDBS in the GPi of PD and dystonia patients. OBJECTIVE AND METHODS We aimed to describe the bursting behaviour of LF and beta oscillations in a cohort of five GPi-DBS PD patients and compare their amplitude and length with those of a cohort of seven GPi-DBS dystonia, and six STN-DBS PD patients (n electrodes = 34). Furthermore, we used the information obtained to set up aDBS and test it in the GPi of both a dystonia and a PD patient (n = 2), using either LF (dystonia) or beta oscillations (PD) as feedback signals. RESULTS LF and beta oscillations in the dystonic and parkinsonian GPi occur as phasic, short-lived bursts, similarly to the parkinsonian STN. The amplitude profile of such bursts, however, differed significantly. Dystonia showed higher LF burst amplitudes, while PD presented higher beta burst amplitudes. Burst characteristics in the parkinsonian GPi and STN were similar. Furthermore, aDBS applied in the GPi was feasible and well tolerated in both diseases. CONCLUSION Pallidal LF and beta burst amplitudes have different characteristics in PD and dystonia. The presence of increased burst amplitudes could be employed as feedback for GPi-aDBS.

Reversal of Status Dystonicus after Relocation of Pallidal Electrodes in DYT6 Generalized Dystonia

Background DYT6 dystonia can have an unpredictable clinical course and the result of deep brain stimulation (DBS) of the internal part of the globus pallidus (GPi) is known to be less robust than in other forms of autosomal dominant dystonia. Patients who had previous stereotactic surgery with insufficient clinical benefit form a particular challenge with very limited other treatment options available. Case Report A pediatric DYT6 patient unexpectedly deteriorated to status dystonicus 1 year after GPi DBS implantation with good initial clinical response. After repositioning the DBS electrodes the status dystonicus resolved. Discussion This case study demonstrates that medication‐resistant status dystonicus in DYT6 dystonia can be reversed by relocation of pallidal electrodes. This case highlights that repositioning of DBS electrodes may be considered in patients with status dystonicus, especially when the electrode position is not optimal, even after an initial clinical response to DBS.

Oscillatory activity and cortical coherence of the nucleus basalis of Meynert in Parkinson's disease dementia

BACKGROUND Deep brain stimulation (DBS) of the nucleus basalis of Meynert (NBM) is a new potential treatment for Parkinsons Disease dementia (PDD) and other types of dementia. To get a better understanding of this structure, its local neurophysiological properties and cortical connectivity patterns were studied. METHODS We simultaneously recorded DBS local field potentials (LFPs) and electroencephalography (EEG) in two patients with PDD. Both patients had DBS electrodes in the internal globus pallidus (GPi) with one or more distal contacts close to or inside the NBM. Measurements were obtained during routine battery replacement. The distance of DBS contacts to the NBM were calculated using CT-MRI fusion. RESULTS Delta (1-4 Hz) oscillations were more prominently present in the NBM region than in its vicinity, whereas temporal coherence in the theta (4-8 Hz) range was less outspoken. CONCLUSION These neurophysiological characteristics, if also proven in larger cohorts, might help to map the NBM more precisely during electrode implantation.

Therapeutic potential of deep brain stimulation of the nucleus accumbens in morbid obesity

OBJECTIVE Morbid obesity is a growing problem worldwide. The current treatment options have limitations regarding effectiveness and complication rates. New treatment modalities are therefore warranted. One of the options is deep brain stimulation (DBS) of the nucleus accumbens (NAC). This review aims to summarize the current knowledge on NAC-DBS for the treatment of morbid obesity. METHODS Studies were obtained from multiple electronic bibliographic databases, supplemented with searches of reference lists. All animal and human studies reporting on the effects of NAC-DBS on body weight in morbidly obese patients were included. Articles found during the search were screened by 2 reviewers, and when deemed applicable, the relevant data were extracted. RESULTS Five relevant animal experimental papers were identified, pointing toward a beneficial effect of high-frequency stimulation of the lateral shell of the NAC. Three human case reports show a beneficial effect of NAC-DBS on body weight in morbidly obese patients. CONCLUSIONS The available literature supports NAC-DBS to treat morbid obesity. The number of well-conducted animal studies, however, is very limited. Also, the optimal anatomical position of the DBS electrode within the NAC, as well as the optimal stimulation parameters, has not yet been established. These matters need to be addressed before this strategy can be considered for human clinical trials.

The mercedes star sign

A 61-year-old woman presented with acute excruciating back pain, rapidly followed by paraplegia, sensory loss (Level Th9), and loss of sphincter tone. She was on longterm phenprocoumon treatment for atrial fibrillation. Her other medical history was unremarkable. Urgent magnetic resonance imaging of the spine showed a lesion suggestive of a spinal hematoma (Figure, Left). The distinction between an intraor extradural localization of a spinal hematoma can be challenging. In this case, however, the transversal magnetic resonance images (Figure, Right) showed the typical sign of an intradural localization, which is easy to recognize and easy to memorize: the mercedes star sign [1]. This appearance is caused by the anatomical properties of the spinal cord that is ‘‘tied up’’ to the dura by the denticulate ligaments. In this case, a Th5–L2 laminectomy with dural opening, evacuation of a spinal intradural hematoma, and dural closure was performed. Six

Deep Brain Stimulation in a Dopaminergic Non-responsive Patient With Parkinson's Disease: Case Report and Systematic Review

P < 0.001); Stimulation side Direction interaction (F[1,4] 1⁄4 9.5; P 1⁄4 0.02)). We provide the first demonstration that LA/RC GVS shifts estimates of whole-body spatial position. A possible explanation for this finding is an altered gain of the peripheral vestibular system. However, for this explanation to hold we would expect to observe biases for both active stimulation conditions, which we do not. Eye movements could also have influenced position estimates. GVS at around 1mA is known to produce both torsional andweak horizontal eye movements toward the anode [9]. However, the fact that we did not observe position biases in both active stimulation conditions also rules out the possibility of a gaze-shift mediated effect. The most parsimonious explanation for our results is that LA/ RC GVS biased spatial attention during the position task. Previous studies have shown that this montage biases visuospatial attention to the left space [1,2,4]. We show that when participants perform a whole-body spatial position task, LA/RC stimulation induces a relative spatial bias toward left space which results in participants underestimating spatial position estimates during rightward whole-body translations, and overestimating spatial position estimates during leftward whole-body translations. Further, these biases are not secondary to numerical biasing as the alphabetical control experiment yielded identical results. To conclude, our data indicates that LA/RC GVS induces hemispheric biases in spatial attentional networks which subsequently disrupts position estimates.