Abstract: Freezing of gait (FOG) in Parkinson's disease (PD) occurs frequently in situations with high environmental complexity. The supplementary motor cortex (SMC) is regarded as a major network node that exerts cortical input for motor control in these situations. We aimed at assessing the impact of single-session (excitatory) intermittent theta burst stimulation (iTBS) of the SMC on established walking during FOG provoking situations such as passing through narrow spaces and turning for directional changes. Twelve PD patients with FOG underwent two visits in the off-medication state with either iTBS or sham stimulation. At each visit, spatiotemporal gait parameters were measured during walking without obstacles and in FOG-provoking situations before and after stimulation. When patients passed through narrow spaces, decreased stride time along with increased stride length and walking speed (i.e., improved gait) was observed after both sham stimulation and iTBS. These effects, particularly on stride time, were attenuated by real iTBS. During turning, iTBS resulted in decreased stride time along with unchanged stride length, a constellation compatible with increased stepping frequency. The observed iTBS effects are regarded as relative gait deterioration. We conclude that iTBS over the SMC increases stepping frequency in PD patients with FOG, particularly in FOG provoking situations

Abstract: The open-face design of the Leksell Vantage frame provides many advantages. However, its more rigid, contoured design offers less flexibility than other frames. This is especially true for posterior fossa approaches. This study explores whether these limitations can be overcome by tailored frame placement using a virtual planning approach. The posterior fossa was accessed in ten patients using the Leksell Vantage frame. Frame placement was planned with the Brainlab Elements software, including a phantom-based (virtual) pre-operative planning approach. A biopsy was performed in all patients; in four, additional laser ablation surgery was performed. The accuracy of virtual frame placement was compared to actual frame placement. The posterior approach was feasible in all patients. In one case, the trajectory had to be adjusted; in another, the trajectory was switched from a right- to a left-sided approach. Both cases showed large deviations from the initially planned frame placement. A histopathological diagnosis was achieved in all patients. The new Leksell Vantage frame can be used to safely target the posterior fossa with a high diagnostic success rate and accuracy. Frame placement needs to be well-planned and executed. This can be facilitated using specific software solutions as demonstrated

Abstract: Study Design: Prospective cohort study. Objectives: The purpose of this prospective study was to evaluate a protocol for radiation-sparing kyphoplasty by assessing dosemetrically recorded radiation exposures to both patient and surgeon. Methods: This prospective clinical study examines the radiation exposure to patient and surgeon during single-level kyphoplasty in 32 thoracolumbar osteoporotic vertebral body fractures (12 OF 2, 9 OF 3, 11 OF 4 types) using a radiation aware surgical protocol between May 2017 and November 2019. The radiation exposure was measured at different locations using film, eye lens and ring dosemeters. Dose values are reported under consideration of lower detection limits of each dosemeter type. Results: A high proportion of dosemeter readings was below the lower detection limits, especially for the surgeon (>90%). Radiation exposure to the surgeon was highest at the unprotected thyroid gland (0.053 ± 0.047 mSv), however only slightly above the lower detection limit of dosemeters (0.044 mSv). Radiation exposure to the patient was highest at the chest (0.349 ± 0.414 mSv) and the gonad (0.186 ± 0.262 mSv). Fluoroscopy time, dose area product and number of fluoroscopic images were 46.0 ± 17.9 sec, 124 ± 109 cGy×cm2, and 35 ± 13 per kyphoplasty, respectively. Back pain significantly improved from 6.8 ± 1.6 to 2.5 ± 1.7 on the numeric rating scale on the first postoperative day (P 0.0001).brbrConclusions:brThe implementation of a strict intraoperative radiation protection protocol allows for safely performed kyphoplasty with ultra-low radiation exposure for the patient and surgeon without exceeding the annual occupational dose limits.brbrTrial registration:

Abstract: Objective Patients affected with von Hippel-Lindau disease often develop multiple hemangioblastomas in the cerebellum and spinal cord. Timing of surgical intervention is difficult and depends largely on the anticipated surgical morbidity. However, data regarding surgical outcome after multiple cerebellar and medullary surgeries are scarce. Our objective was to evaluate cumulative surgical morbidity in patients operated on multiple cerebellar and medullary hemangioblastomas and to deduce recommendations for treatment. Methods We performed a retrospective analysis for a consecutive cohort of von Hippel-Lindau patients with surgical treatment of at least two cerebellar and/or medullary hemangioblastomas. Pre- and postoperative functional grades were reviewed in patients' files and compared by Modified Ranking Scale (cerebellar surgeries) or by Modified McCormick Score (medullary surgeries). Results Thirty-six patients were surgically treated for at least two cerebellar hemangioblastomas (12 patients), at least two medullary hemangioblastomas (19 patients) or at least two hemangioblastomas in both locations (5 patients). Fourthy-eight cerebellar and 80 medullary procedures were performed in total. On average, multiple cerebellar surgeries caused no clinical deterioration, whereas multiple medullary surgeries led to a slight cumulative deterioration of postoperative functional grades. The severity of this deterioration did not correlate to the number of performed medullary surgeries. Conclusion Resection of multiple cerebellar hemangioblastomas is not associated with cumulative morbidity. Although there is a certain cumulative surgical morbidity caused by medullary surgeries, its extent does not increase with the number of performed surgeries. Microsurgical removal of asymptomatic tumors with radiographic progression can also be considered for patients with multiple tumors and previous surgeries

Abstract: Background Meningiomas are common brain tumours that are usually defined by benign clinical course. However, some meningiomas undergo a malignant transformation and recur within a short time period regardless of their World Health Organization (WHO) grade. The current study aimed to identify potential markers that can discriminate between benign and malignant meningioma courses. Methods We profiled the metabolites from 43 patients with low- and high-grade meningiomas. Tumour specimens were analyzed by nuclear magnetic resonance analysis; 270 metabolites were identified and clustered with the AutoPipe algorithm. Results We observed two distinct clusters marked by alterations in glycine/serine and choline/tryptophan metabolism. Glycine/serine cluster showed significantly lower WHO grades and proliferation rates. Also progression-free survival was significantly longer in the glycine/serine cluster. Conclusion Our findings suggest that alterations in glycine/serine metabolism are associated with lower proliferation and more recurrent tumours. Altered choline/tryptophan metabolism was associated with increases proliferation, and recurrence. Our results suggest that tumour malignancy can be reflected by metabolic alterations, which may support histological classifications to predict the clinical outcome of patients with meningiomas

Abstract: Background Intraoperative 3-dimensional (3D) navigation is increasingly being used for pedicle screw placement. For this purpose, dedicated mobile 3D C-arms are capable of providing intraoperative fluoroscopy-based 3D image data sets. Modern 3D C-arms have a large field of view, which suggests a higher radiation exposure. In this experimental study we therefore investigate the radiation exposure of a new mobile 3D C-arm with large flat-panel detector to a previously reported device with regular flat-panel detector on an Alderson phantom. Methods We measured the radiation exposure of the Vision RFD 3D (large 30 × 30 cm detector) while creating 3D image sets as well as standard fluoroscopic images of the cervical and lumbar spine using an Alderson phantom. The dosemeter readings were then compared with the radiation exposure of the previous model Vision FD Vario 3D (smaller 20 × 20 cm detector), which had been examined identically in advance and published elsewhere. Results The larger 3D C-arm induced lower radiation exposures at all dosemeter sites in cervical 3D scans as well as at the sites of eye lenses and thyroid gland in lumbar 3D scans. At ​​male and especially female gonads in lumbar 3D scans, however, the larger 3D C-arm showed higher radiation exposures compared with the smaller 3D C-arm. In lumbar fluoroscopic images, the dosemeters near/in the radiation field measured a higher radiation exposure using the larger 3D C-arm. Conclusions The larger 3D C-arm offers the possibility to reduce radiation exposures for specific applications despite its larger flat-panel detector with a larger field of view. However, due to the considerably higher radiation exposure of the larger 3D C-arm during lumbar 3D scans, the smaller 3D C-arm is to be recommended for short-distance instrumentations (mono- and bilevel) from a radiation protection point of view. The larger 3D C-arm with its enlarged 3D image set might be used for long instrumentations of the lumbar spine. From a radiation protection perspective, the use of the respective 3D C-arm should be based on the presented data and the respective application

Abstract: Automatic anatomical segmentation of patients' anatomical structures and modeling of the volume of tissue activated (VTA) can potentially facilitate trajectory planning and post-operative programming in deep brain stimulation (DBS). We demonstrate an approach to evaluate the accuracy of such software for the ventral intermediate nucleus (VIM) using directional leads. In an essential tremor patient with asymmetrical brain anatomy, lead placement was adjusted according to the suggested segmentation made by the software (Brainlab). Postoperatively, we used directionality to assess lead placement using side effect testing (internal capsule and sensory thalamus). Clinical effects were then compared to the patient-specific visualization and VTA simulation in the GUIDETM XT software (Boston Scientific). The patient's asymmetrical anatomy was correctly recognized by the software and matched the clinical results. VTA models matched best for dysarthria (6 out of 6 cases) and sensory hand side effects (5/6), but least for facial side effects (1/6). Best concordance was observed for the modeled current anterior and back spread of the VTA, worst for the current side spread. Automatic anatomical segmentation and VTA models can be valuable tools for DBS planning and programming. Directional DBS leads allow detailed postoperative assessment of the concordance of such image-based simulation and visualization with clinical effects