Reducing radiation exposure and costs: CT body scout views with an enhanced protocol versus conventional radiography after shunt surgery

OBJECTIVE

Ventriculoperitoneal shunt implantation has become standard treatment for cerebrospinal fluid diversion, besides endoscopic third ventriculostomy for certain indications. Postoperative X-ray radiography series of skull, chest and abdomen combined with cranial CT are obtained routinely in many institutions to document the shunt position and valve settings in adult patients. Measures to reduce postoperative radiation exposure are needed, however, there is only limited experience with such efforts. Here, we aim to compare routine postoperative cranial CT plus conventional radiography series (retrospective arm) with cranial CT and body scout views only (prospective arm) concerning both diagnostic quality and radiation exposure.

PATIENTS AND METHODS

After introduction of an enhanced CT imaging protocol, routine skull and abdomen radiography was no longer obtained after VP shunt surgery. The image studies of 25 patients with routine postoperative cranial CT and conventional radiography (retrospective arm of study) were then compared to 25 patients with postoperative cranial CT and CT body scout views (prospective arm of study). Patient demographics such as age, sex and primary diagnosis were collected. The image quality of conventional radiographic images and computed tomography scout views images were independently analyzed by one neurosurgeon and one neuroradiologist.

RESULTS

There were no differences in quality assessments according to three different factors determined by two independent investigators for both groups. There was a statistically significant difference, however, between the conventional radiography series group and the CT body scout view imaging group with regard to radiation exposure. The effective dose estimation calculation yielded a difference of 0.05 mSv (two-tailed t-test, p = 0.044) in favor of CT body scout view imaging. Furthermore, the new enhanced protocol resulted in a reduction of cost and the use of human resources.

CONCLUSION

CT body scout view imaging provides sufficient imaging quality to determine shunt positioning and valve settings. With regard to radiation exposure and costs, we suggest that conventional postoperative shunt series may be abandoned.

Somatosensory evoked potentials recorded from DBS electrodes: the origin of subcortical N18

The different peaks of somatosensory-evoked potentials (SEP) originate from a variety of anatomical sites in the central nervous system. The origin of the median nerve subcortical N18 SEP has been studied under various conditions, but the exact site of its generation is still unclear. While it has been claimed to be located in the thalamic region, other studies indicated its possible origin below the pontomedullary junction. Here, we scrutinized and compared SEP recordings from median nerve stimulation through deep brain stimulation (DBS) electrodes implanted in various subcortical targets. We studied 24 patients with dystonia, Parkinson's disease, and chronic pain who underwent quadripolar electrode implantation for chronic DBS and recorded median nerve SEPs from globus pallidus internus (GPi), subthalamic nucleus (STN), thalamic ventral intermediate nucleus (Vim), and ventral posterolateral nucleus (VPL) and the centromedian-parafascicular complex (CM-Pf). The largest amplitude of the triphasic potential of the N18 complex was recorded in Vim. Bipolar recordings confirmed the origin to be close to Vim electrodes (and VPL/CM-Pf) and less close to STN electrodes. GPi recorded only far-field potentials in unipolar derivation. Recordings from DBS electrodes located in different subcortical areas allow determining the origin of certain subcortical SEP waves more precisely. The subcortical N18 of the median nerve SEP-to its largest extent-is generated ventral to the Vim in the region of the prelemniscal radiation/ zona incerta.

Subthalamic Nucleus Deep Brain Stimulation Restores Motor and Sensorimotor Cortical Neuronal Oscillatory Activity in the Free-Moving 6-Hydroxydopamine Lesion Rat Parkinson Model

OBJECTIVES

Enhanced beta oscillations in cortical-basal ganglia (BG) thalamic circuitries have been linked to clinical symptoms of Parkinson's disease. Deep brain stimulation (DBS) of the subthalamic nucleus (STN) reduces beta band activity in BG regions, whereas little is known about activity in cortical regions. In this study, we investigated the effect of STN DBS on the spectral power of oscillatory activity in the motor cortex (MCtx) and sensorimotor cortex (SMCtx) by recording via an electrocorticogram (ECoG) array in free-moving 6-hydroxydopamine (6-OHDA) lesioned rats and sham-lesioned controls.

MATERIALS AND METHODS

Male Sprague-Dawley rats (250-350 g) were injected either with 6-OHDA or with saline in the right medial forebrain bundle, under general anesthesia. A stimulation electrode was then implanted in the ipsilateral STN, and an ECoG array was placed subdurally above the MCtx and SMCtx areas. Six days after the second surgery, the free-moving rats were individually recorded in three conditions: 1) basal activity, 2) during STN DBS, and 3) directly after STN DBS.

RESULTS

In 6-OHDA-lesioned rats (N = 8), the relative power of theta band activity was reduced, whereas activity of broad-range beta band (12-30 Hz) along with two different subbeta bands, that is, low (12-30 Hz) and high (20-30 Hz) beta band and gamma band, was higher in MCtx and SMCtx than in sham-lesioned controls (N = 7). This was, to some extent, reverted toward control level by STN DBS during and after stimulation. No major differences were found between contacts of the electrode grid or between MCtx and SMCtx.

CONCLUSION

Loss of nigrostriatal dopamine leads to abnormal oscillatory activity in both MCtx and SMCtx, which is compensated by STN stimulation, suggesting that parkinsonism-related oscillations in the cortex and BG are linked through their anatomic connections.

Primary and secondary gliosarcoma: differences in treatment and outcome

INTRODUCTION

There are only few studies comparing differences in the outcome of primary versus secondary gliosarcoma. This study aimed to review the outcome and survival of patients with primary or secondary gliosarcoma following surgical resection and adjuvant treatment. The data were also matched with data of patients with primary and secondary glioblastoma (GBM).

PATIENTS AND METHODS

Treatment histories of 10 patients with primary gliosarcoma and 10 patients with secondary gliosarcoma were analysed and compared. Additionally, data of 20 patients with primary and 20 patients with secondary GBM were analysed and compared. All patients underwent surgical resection of the tumour in our department. Follow-up data, progression-free survival (PFS), and median overall survival (mOS) were evaluated.

RESULTS

The median PFS in patients with primary gliosarcoma was significantly higher than in patients with secondary gliosarcoma (p = 0.037). The 6-month PFS rates were 80.0% in patients with primary and 30.0% in patients with secondary gliosarcoma. Upon recurrence, five patients with primary gliosarcoma and four patients with secondary gliosarcoma underwent repeat surgical resection. The mOS of patients with primary gliosarcoma was significantly higher than that of patients with secondary gliosarcoma (p = 0.031). The percentage of patients surviving at 1-year/2-year follow-up in primary gliosarcoma was 70%/20%, while it was only 10%/10% in secondary gliosarcoma. When PFS and mOS of primary gliosarcoma was compared to primary GBM, there were no statistically differences (p = 0.509; p = 0.435). The PFS and mOS of secondary gliosarcoma and secondary GBM were also comparable (p = 0.290 and p = 0.390).

CONCLUSION

Patients with primary gliosarcoma have a higher PFS and mOS compared to those with secondary gliosarcoma. In the case of tumour recurrence, patients with secondary gliosarcoma harbour an unfavourable prognosis with limited further options. The outcome of patients with primary or secondary gliosarcoma is comparable to that of patients with primary or secondary GBM.

External ventricular drainage in pediatric patients: indications, management, and shunt conversion rates

PURPOSE

Placement of an external ventricular drainage (EVD) is one of the most frequent procedures in neurosurgery, but it has specific challenges and risks in the pediatric population. We here investigate the indications, management, and shunt conversion rates of an EVD.

METHODS

We retrospectively analyzed the data of a consecutive series of pediatric patients who had an EVD placement in the Department of Neurosurgery at Hannover Medical School over a 12-year period. A bundle approach was introduced to reduce infections. Patients were categorized according to the underlying pathology in three groups: tumor, hemorrhage, and infection.

RESULTS

A total of 126 patients were included in this study. Seventy-two were male, and 54 were female. The mean age at the time of EVD placement was 5.2 ± 5.0 years (range 0-17 years). The largest subgroup was the tumor group (n = 54, 42.9%), followed by the infection group (n = 47, 37.3%), including shunt infection (n = 36), infected Rickham reservoir (n = 4), and bacterial or viral cerebral infection (n = 7), and the hemorrhage group (n = 25, 19.8%). The overall complication rate was 19.8% (n = 25/126), and the total number of complications was 30. Complications during EVD placement were noted in 5/126 (4%) instances. Complications during drainage time were infection in 9.5% (12 patients), dysfunction in 7.1% (9 patients), and EVD dislocation in 3.2% (4 patients). The highest rate of complications was seen in the hemorrhage group. There were no long-term complications. Conversion rates into a permanent shunt system were 100% in previously shunt-dependent patients. Conversion rates were comparable in the tumor group (27.7%) and in the hemorrhage group (32.0%).

CONCLUSION

EVD placement in children is an overall safe and effective option in children. In order to make further progress, carefully planned prospective and if possible randomized studies are needed controlling for multivariable aspects.

Does Temporary Externalization of Electrodes After Deep Brain Stimulation Surgery Result in a Higher Risk of Infection?

OBJECTIVES

Deep brain stimulation (DBS) is a well-established surgical therapy for movement disorders that comprises implantation of stimulation electrodes and a pacemaker. These procedures can be performed separately, leaving the possibility of externalizing the electrodes for local field potential recording or testing multiple targets for therapeutic efficacy. It is still debated whether the temporary externalization of DBS electrodes leads to an increased risk of infection. We therefore aimed to assess the risk of infection during and after lead externalization in DBS surgery.

MATERIALS AND METHODS

In this retrospective study, we analyzed a consecutive series of 624 DBS surgeries, including 266 instances with temporary externalization of DBS electrodes for a mean of 6.1 days. Patients were available for follow-up of at least one year, except in 15 instances. In 14 patients with negative test stimulation, electrodes were removed. All kinds of infections related to implantation of the neurostimulation system were accounted for.

RESULTS

Overall, infections occurred in 22 of 624 surgeries (3.5%). Without externalization of electrodes, infections were noted after 7 of 358 surgeries (2.0%), whereas with externalization, 15 of 252 infections were found (6.0%). This difference was significant (p = 0.01), but it did not reach statistical significance when comparing groups within different diagnoses. The rate of infection with externalized electrodes was highest in psychiatric disorders (9.1%), followed by Parkinson's disease (7.3%), pain (5.7%), and dystonia (5.5%). The duration of the externalization of the DBS electrodes was comparable in patients who developed an infection (6.1 ± 3.1 days) with duration in those who did not (6.0 ± 3.5 days).

CONCLUSIONS

Although infection rates were relatively low in our study, there was a slightly higher infection rate when DBS electrodes were externalized. On the basis of our results, the indication for electrode externalization should be carefully considered, and patients should be informed about the possibility of a higher infection risk when externalization of DBS electrodes is planned.

Assessing the feasibility of the transmastoid infralabyrinthine approach without decompression of the jugular bulb to the extradural part of the petrous apex and petroclival junction prior to surgery

BACKGROUND AND OBJECTIVE

This study aims to define specific measurements on cranial high-resolution computed tomography (HRCT) images prior to surgery to prove the feasibility of the navigated transmastoid infralabyrinthine approach (TI-A) without rerouting of the facial nerve (FN) and decompression of the jugular bulb (JB) in accessing the extradural-intrapetrous part of petrous bone lesions located at the petrous apex and petroclival junction.

MATERIALS AND METHODS

Vertical and horizontal distances of the infralabyrinthine space were measured on cranial HRCT images prior to dissection. Subsequently, the area of access was measured on dissected human cadaveric specimens. Infralabyrinthine access to the extradural part of the petrous apex and petroclival junction was evaluated on dissected specimens by two independent raters. Finally, the vertical and horizontal distances were correlated with the area of access.

RESULTS

Fourteen human cadaveric specimens were dissected bilaterally. In 54% of cases, the two independent raters determined appropriate access to the petrous apex and petroclival junction. A highly significant positive correlation (r = 0.99) was observed between the areas of access and the vertical distances. Vertical distances above 5.2 mm were considered to permit suitable infralabyrinthine access to the extradural area of the petrous apex and petroclival junction.

CONCLUSIONS

Prior to surgery, vertical infralabyrinthine distances on HRCT images above 5.2 mm provide suitable infralabyrinthine access to lesions located extradurally at the petrous apex and petroclival junction via the TI-A without rerouting of the FN and without decompression of the JB.

Large-Scale Screening: Phenotypic and Mutational Spectrum in Isolated and Combined Dystonia Genes

BACKGROUND

Pathogenic variants in several genes have been linked to genetic forms of isolated or combined dystonia. The phenotypic and genetic spectrum and the frequency of pathogenic variants in these genes have not yet been fully elucidated, neither in patients with dystonia nor with other, sometimes co-occurring movement disorders such as Parkinson's disease (PD).

OBJECTIVES

To screen >2000 patients with dystonia or PD for rare variants in known dystonia-causing genes.

METHODS

We screened 1207 dystonia patients from Germany (DysTract consortium), Spain, and South Korea, and 1036 PD patients from Germany for pathogenic variants using a next-generation sequencing gene panel. The impact on DNA methylation of KMT2B variants was evaluated by analyzing the gene's characteristic episignature.

RESULTS

We identified 171 carriers (109 with dystonia [9.0%]; 62 with PD [6.0%]) of 131 rare variants (minor allele frequency <0.005). A total of 52 patients (48 dystonia [4.0%]; four PD [0.4%, all with GCH1 variants]) carried 33 different (likely) pathogenic variants, of which 17 were not previously reported. Pathogenic biallelic variants in PRKRA were not found. Episignature analysis of 48 KMT2B variants revealed that only two of these should be considered (likely) pathogenic.

CONCLUSION

This study confirms pathogenic variants in GCH1, GNAL, KMT2B, SGCE, THAP1, and TOR1A as relevant causes in dystonia and expands the mutational spectrum. Of note, likely pathogenic variants only in GCH1 were also found among PD patients. For DYT-KMT2B, the recently described episignature served as a reliable readout to determine the functional effect of newly identified variants. © 2024 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Hearing loss in juvenile rats leads to excessive play fighting and hyperactivity, mild cognitive deficits and altered neuronal activity in the prefrontal cortex

Background

In children, hearing loss has been associated with hyperactivity, disturbed social interaction, and risk of cognitive disturbances. Mechanistic explanations of these relations sometimes involve language. To investigate the effect of hearing loss on behavioral deficits in the absence of language, we tested the impact of hearing loss in juvenile rats on motor, social, and cognitive behavior and on physiology of prefrontal cortex.

Methods

Hearing loss was induced in juvenile (postnatal day 14) male Sprague-Dawley rats by intracochlear injection of neomycin under general anesthesia. Sham-operated and non-operated hearing rats served as controls. One week after surgery auditory brainstem response (ABR) measurements verified hearing loss or intact hearing in sham-operated and non-operated controls. All rats were then tested for locomotor activity (open field), coordination (Rotarod), and for social interaction during development in weeks 1, 2, 4, 8, 16, and 24 after surgery. From week 8 on, rats were trained and tested for spatial learning and memory (4-arm baited 8-arm radial maze test). In a final setting, neuronal activity was recorded in the medial prefrontal cortex (mPFC).

Results

In the open field deafened rats moved faster and covered more distance than sham-operated and non-operated controls from week 8 on (both p < 0.05). Deafened rats showed significantly more play fighting during development (p < 0.05), whereas other aspects of social interaction, such as following, were not affected. Learning of the radial maze test was not impaired in deafened rats (p > 0.05), but rats used less next-arm entries than other groups indicating impaired concept learning (p < 0.05). In the mPFC neuronal firing rate was reduced and enhanced irregular firing was observed. Moreover, oscillatory activity was altered, both within the mPFC and in coherence of mPFC with the somatosensory cortex (p < 0.05).

Conclusions

Hearing loss in juvenile rats leads to hyperactive behavior and pronounced play-fighting during development, suggesting a causal relationship between hearing loss and cognitive development. Altered neuronal activities in the mPFC after hearing loss support such effects on neuronal networks outside the central auditory system. This animal model provides evidence of developmental consequences of juvenile hearing loss on prefrontal cortex in absence of language as potential confounding factor.

Surgical site infections after glioblastoma surgery: boon or bane?

BACKGROUND

Surgical site infections (SSIs) are among the most common postoperative complications. Glioblastoma multiforme is the most frequent malignant brain tumor with a dismal prognosis despite combined treatment. The effect of SSIs on the course of glioblastoma patients has not been fully clarified since available data are limited and partially contradictory. The aim of this study is to investigate the impact of SSIs on the course of patients with glioblastoma.

METHODS

The medical records of all patients undergoing surgery for glioblastoma between 2010 and 2020 in our institution were scanned and those with surgical site infections after glioblastoma resection were identified and compared to an age-matched control group. Overall survival and progression-free survival were the primary endpoints followed by the number of hospitalizations and the length of stay in hospital.

RESULTS

Out of 305 patients undergoing surgery for glioblastoma, 38 patients with postoperative surgical site infection after resection were identified and 15 (5 men and 10 women aged between 9 and 72) were included in this study. 23 patients were excluded. The control group consisted of 30 age-matched patients without SSI (18 men and 12 women). There were no significant differences in median overall survival. Progression-free survival was higher in the SSI group. The number of hospitalizations and the length of stay were significantly higher in the SSI group.

CONCLUSION

Our data suggest that SSIs might reduce early recurrences without affecting overall survival. Furthermore, they might decrease health-related quality of life by doubling the total length of hospital stay.

Task design for crowdsourced glioma cell annotation in microscopy images

Crowdsourcing has been used in computational pathology to generate cell and cell nuclei annotations for machine learning. Herein, we broaden its scope to the previously unsolved challenging task of glioma cell detection. This requires multiplexed immunofluorescence microscopy due to diffuse invasiveness and exceptional similarity between glioma cells and reactive astrocytes. In four pilot experiments, we iteratively developed a task design enabling high-quality annotations by crowdworkers on Amazon Mechanical Turk. We applied majority or weighted vote and validated them against ground truth in the final setting. On the base of a YOLO convolutional neural network architecture, we used these consensus labels for training with different image representations regarding colors, intensities, and immmunohistochemical marker combinations. A crowd of 712 workers defined aggregated point annotations in 235 images with an average [Formula: see text] score of 0.627 for majority vote. The networks resulted in acceptable [Formula: see text] scores up to 0.69 for YOLOv8 on average and indicated first evidence for transferability to images lacking tumor markers, especially in IDH-wildtype glioblastoma. Our work confirms feasibility of crowdsourcing to generate labels suitable for training of machine learning tools in the challenging and clinically relevant use case of glioma microenvironment.

Vagus nerve stimulation for the treatment of narcolepsy

BACKGROUND AND OBJECTIVE

No study on neurostimulation in narcolepsy is available until now. Arousal- and wake-promoting effects of vagus nerve stimulation (VNS) have been demonstrated in animal experiments and are well-known as side effects of VNS therapy in epilepsy and depression. The objective was to evaluate the therapeutic effect of VNS on daily sleepiness and cataplexies in narcolepsy.

METHODS

In our open-label prospective comparative study, we included narcolepsy patients who were treated with VNS because of depression or epilepsy and compared them to controls without narcolepsy treated with VNS for depression or epilepsy (18 patients in each group, aged 31.5 ± 8.2 years). We evaluated daily sleepiness (Epworth Sleepiness Scale, ESS) and the number of cataplexies per week before the implantation of VNS and at three and six month follow-ups.

RESULTS

Compared to baseline (ESS: 15.9 ± 2.5) patients with narcolepsy showed a significant improvement on ESS after three months (11.2 ± 3.3, p < 0.05) and six months (9.6 ± 2.8, p < 0.001) and a trend to reduction of cataplexies. No significant ESS-improvement was observed in patients without narcolepsy (14.9 ± 3.9, 13.6 ± 3.7, 13.2 ± 3.5, p = 0.2 at baseline, three and six months, correspondingly). Side effects did not differ between the study groups.

CONCLUSION

In this first evaluation of VNS in narcolepsy, we found a significant improvement of daily sleepiness due to this type of neurostimulation. VNS could be a promising non-medical treatment in narcolepsy.

Outcomes of Unilateral Pallidotomy in Focal and Hemidystonia Cases: A Single-Blind Cohort Study

BACKGROUND

The role of deep brain stimulation in the treatment of dystonia has been widely documented. However, there is limited literature on the outcome of lesioning surgery in unilateral dystonia.

OBJECTIVE

We restrospectively reviewed our cases of focal and hemidystonia undergoing unilateral Pallidotomy at our institute to evaluate the short-term and long-term outcome.

METHODS

Patients who underwent radiofrequency lesioning of GPi for unilateral dystonia between 1999 and 2019 were retrospectively reviewed. All patients were evaluated using the Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS) and Dystonia Disability Scale (DDS) preoperatively at the short term follow-up (<1 year) and at long-term follow-up (2-7.5 years). Video recordings performed at these time points were independently reviewed by a blinded movement disorders specialist.

RESULTS

Eleven patients were included for analysis. The preoperative, short-term, and long-term follow-up motor BFMDRS and DDS scores were 15.5 (IQR [interquartile range]: 10.5, 23.75) and 10.5 (IQR: 6.0, 14.5); 3.0 (IQR: 1.0, 6.0, P = 0.02) and 3.0 (IQR: 3.0, 8.0, P = 0.016); and 14.25 (IQR: 4.0, 20.0, P = 0.20) and 10.5 (IQR: 2.0, 15.0, P = 0.71) respectively. For observers B, the BFMDRS scores at the same time points were 19 (IQR: 12.5, 27.0), 7.5 (IQR: 6.0, 15.0, P = 0.002), and 21 (IQR: 7.0, 22.0, P = 0.65) respectively. The improvement was statistically significant for all observations at short-term follow-up but not at long-term follow-up.

CONCLUSION

Pallidotomy is effective for hemidystonia or focal dystonia in the short term. Continued benefit was seen in the longer term in some patients, whereas others worsened. Larger studies may be able to explain this in future.

Favorable combinations of antiseizure medication with vagus nerve stimulation to improve health-related quality of life in patients with epilepsy

BACKGROUND

Vagus nerve stimulation (VNS) is a non-pharmacological treatment of refractory epilepsy, which also has an antidepressive effect. The favorable combinations of VNS with specific mechanisms of action of antiseizure medication (ASM) on mood and health-related quality of life (HrQol) have not yet been studied. The objective was to identify favourable combinations of specific ASMs with VNS for the HrQoL and depression in refractory epilepsy.

METHODS

We performed an observational study including patients with refractory epilepsy and an implanted VNS (N = 151). In the first 24 months after VNS implantation, all patients were on stable ASM therapy. We used the standardized questionnaires QOLIE10, EQVAS and EQ5D to evaluate HrQoL as well as the Beck Depression Inventory (BDI). Multiple regression analysis was performed to evaluate the synergistic combinations of ASM with VNS for HrQoL.

RESULTS

At the year-two follow-up (N = 151, age 45.2 ± 17.0 years), significant improvement (p < 0.05) in BDI scores was found for combination of VNS with SV2A modulators (58.4 %) or AMPA antagonists (44.4 %). A significant increase of HrQoL by at least 30 % (p < 0.05) was measured for a combination of VNS with SV2A modulators (brivaracetam, levetiracetam) or slow sodium channel inhibitors (eslicarbazepine, lacosamide).

CONCLUSION

The results of our study suggests a favorable effect of the combination of SV2A modulators or slow sodium channel inhibitors with VNS on the HrQoL in comparison to other ASMs. Besides the possible synergistic effects on the seizure frequency, the amelioration of behavioral side effects of SV2A modulators by VNS is an important factor of HrQoL-improvement in these combinations.

Surgical treatment of spondylodiscitis in critically ill septic patients

PURPOSE

Surgical procedures in critically ill patients with spondylodiscitis are challenging and there are several controversies. Here, we present our experience with offering surgical intervention early in critically ill septic patients with spondylodiscitis.

METHOD

After we introduced a new treatment paradigm offering early but limited surgery, eight patients with spondylodiscitis complicated by severe sepsis and multiple organ failure underwent urgent surgical treatment over a 10-year period. Outcome was assessed according to the Barthel index at 12-month follow-up and at the last available follow-up (mean 89 months).

RESULTS

There were 7 men and 1 woman, with a mean age of 62 years. The preoperative ASA score was 5 in 2 patients, and 4 in 6 patients. Six of them presented with high-grade paresis, and in all of them, spondylodiscitis with intraspinal and/or paravertebral abscesses was evident in MR imaging studies. All patients underwent early surgery (within 24 h after admission). The median time in intensive care was 21 days. Out of the eight patients, seven survived. One year after surgery, five patients had a good outcome (Barthel index: 100 (1); 80 (3); and 70 (1)). At the last follow-up (mean 89 months), 4 patients had a good functional outcome (Barthel index between 60 and 80).

CONCLUSION

Early surgical treatment in critically ill patients with spondylodiscitis and sepsis may result in rapid control of infection and can provide favorable long-term outcome. A general strategy of performing only limited surgery is a valid option in such patients who have a relatively high risk for surgery.

Microsurgical posterior fossa re-exploration for recurrent trigeminal neuralgia after previous microvascular decompression: common grounds-scarring, deformation, and the "piston effect"

OBJECTIVE

Microvascular decompression (MVD) is a well-accepted treatment modality for trigeminal neuralgia (TN) with high initial success rates. The causes for recurrence of TN after previously successful MVD have not been fully clarified, and its treatment is still a matter of debate. Here, we present the surgical findings and the clinical outcome of patients with recurrent TN after MVD who underwent posterior fossa re-exploration.

METHODS

Microsurgical posterior fossa re-exploration was performed in 26 patients with recurrent TN (mean age 59.1 years) who underwent MVD over a period of 10 years. The trigeminal nerve was exposed, and possible factors for recurrent TN were identified. Arachnoid scars and Teflon granulomas were dissected meticulously without manipulating the trigeminal nerve. Outcome of posterior fossa re-exploration was graded according to the Barrow Neurological Institute (BNI) pain intensity score. Follow-up was analyzed postoperatively at 3, 12, and 24 months and at the latest available time point for long-term outcome.

RESULTS

The mean duration of recurrent TN after the first MVD was 20 months. Pain relief was achieved in all patients with recurrent TN on the first postoperative day. Intraoperative findings were as follows: arachnoid scar tissue in 22/26 (84.6%) patients, arterial compression in 1/26 (3.8%), venous contact in 8/26 (30.8%), Teflon granuloma in 14/26 (53.8%), compression by an electrode in Meckel's cave used for treatment of neuropathic pain in 1/26 (3.8%), evidence of pulsations transmitted to the trigeminal nerve through the Teflon inserted previously/scar tissue ("piston effect") in 15/26 (57.7%), and combination of findings in 18/26 (69.2%). At long-term follow-up (mean 79.5 months; range, 29-184 months), 21/26 (80.8%) patients had favorable outcome (BNI I-IIIa). New hypaesthesia secondary to microsurgical posterior fossa re-exploration occurred in 5/26 (19.2%) patients.

CONCLUSIONS

Posterior fossa re-exploration avoiding manipulation to the trigeminal nerve, such as pinching or combing, may be a useful treatment option for recurrent TN after previously successful MVD providing pain relief in the majority of patients with a low rate of new hypaesthesia.

Rare germline variants in POLE and POLD1 encoding the catalytic subunits of DNA polymerases ε and δ in glioma families

Pathogenic germline variants in the DNA polymerase genes POLE and POLD1 cause polymerase proofreading-associated polyposis, a dominantly inherited disorder with increased risk of colorectal carcinomas and other tumors. POLE/POLD1 variants may result in high somatic mutation and neoantigen loads that confer susceptibility to immune checkpoint inhibitors (ICIs). To explore the role of POLE/POLD1 germline variants in glioma predisposition, whole-exome sequencing was applied to leukocyte DNA of glioma patients from 61 tumor families with at least one glioma case each. Rare heterozygous POLE/POLD1 missense variants predicted to be deleterious were identified in glioma patients from 10 (16%) families, co-segregating with the tumor phenotype in families with available DNA from several tumor patients. Glioblastoma patients carrying rare POLE variants had a mean overall survival of 21 months. Additionally, germline variants in POLD1, located at 19q13.33, were detected in 2/34 (6%) patients with 1p/19q-codeleted oligodendrogliomas, while POLE variants were identified in 2/4 (50%) glioblastoma patients with a spinal metastasis. In 13/15 (87%) gliomas from patients carrying POLE/POLD1 variants, features of defective polymerase proofreading, e.g. hypermutation, POLE/POLD1-associated mutational signatures, multinucleated cells, and increased intratumoral T cell response, were observed. In a CRISPR/Cas9-derived POLE-deficient LN-229 glioblastoma cell clone, a mutator phenotype and delayed S phase progression were detected compared to wildtype POLE cells. Our data provide evidence that rare POLE/POLD1 germline variants predispose to gliomas that may be susceptible to ICIs. Data compiled here suggest that glioma patients carrying POLE/POLD1 variants may be recognized by cutaneous manifestations, e.g. café-au-lait macules, and benefit from surveillance colonoscopy.

Microelectrode recording and hemorrhage in functional neurosurgery: a comparative analysis in a consecutive series of 645 procedures

OBJECTIVE

Functional stereotactic neurosurgery including deep brain stimulation (DBS) and radiofrequency lesioning is well established and widely used for treatment of movement disorders and various other neurological and psychiatric diseases. Although functional stereotactic neurosurgery procedures are considered relatively safe, intracranial hemorrhage resulting in permanent neurological deficits may occur in 1%-3% of patients. Microelectrode recording (MER) has been recognized as a valuable tool for refining the final target in functional stereotactic neurosurgery. Moreover, MER provides insight into the underlying neurophysiological pathomechanisms of movement disorders and other diseases. Nevertheless, there is an ongoing controversy on whether MER increases the risk for hemorrhage. The authors aimed to compare the risk of hemorrhage in functional stereotactic neurosurgical procedures with regard to the use of MER.

METHODS

The authors performed a comparative analysis on a consecutive series of 645 functional neurosurgery procedures, including 624 DBS surgeries and 21 radiofrequency lesionings, to evaluate whether the use of MER would increase the risk for hemorrhage. MER was performed in 396 procedures, while no MER was used in 249 cases. The MER technique involved the use of a guiding cannula and a single trajectory when feasible. Postoperative CT scans were obtained within 24 hours after surgery in all patients and screened for the presence of hemorrhage.

RESULTS

Twenty-one intracranial hemorrhages were detected on the postoperative CT scans (3.2%). Of the 21 intracranial hemorrhages, 14 were asymptomatic and 7 were symptomatic. Symptoms were transient except in 1 case. There was no statistically significant correlation between hemorrhage and the use of MER at any site (subdural, ventricle, trajectory, target, whether asymptomatic or symptomatic). There were 4 cases of symptomatic hemorrhage in the MER group (1%) and 3 cases in those without MER (1.2%).

CONCLUSIONS

Intraoperative MER did not increase the overall risk of hemorrhage in the authors' experience using primarily a single MER trajectory and a guiding cannula.

Early clinical experience with the new generation Pipeline Vantage flow diverter in the treatment of unruptured saccular aneurysms using short-term dual antiplatelet therapy

PURPOSE

The Pipeline Vantage flow diverter with Shield technology (PV) used in this study is a 4th-generation flow diverter (FD) designed to reduce thrombogenicity, promote endothelialization of the implant and increase efficiency in achieving aneurysm closure. In this study, we report the aneurysm occlusion rate, complication rate and clinical outcome with short-term dual antiplatelet therapy (DAPT) in the treatment of unruptured intracranial saccular aneurysms using the PV.

METHODS

We retrospectively identified patients treated between September 2021 and January 2023 with the PV and subsequently underwent short-term DAPT for 3 months. Patient and aneurysm characteristics, peri- and post-procedural complications, clinical outcomes and the grade of aneurysm occlusion were documented.

RESULTS

Thirty patients with 32 aneurysms were treated. Successful FD implantation was achieved in all cases (100%). No periprocedural complications were documented. The overall symptomatic complication rate was 10% and the neurologic, treatment-related symptomatic complication rate was 6.6%. Only one symptomatic complication (3.3%) was device-related. Permanent clinical deterioration occurred in 2/30 patients (6.6%), leading to deterioration of the mRS within the first 3 months after treatment. No mortality was documented. The rate of complete aneurysm occlusion after 3 months and after a mean imaging follow-up of 9.9 months was 65.6% and 75%, respectively.

CONCLUSION

Implantation of the PV for the treatment of saccular intracranial aneurysms achieves a good aneurysm occlusion rate with a low rate of complications. In addition, the use of short-term DAPT after PV implantation appears to be safe.

Patient-specific implants for reconstruction of orbit and skull following resection of spheno-orbital meningiomas: A two-implant concept

INTRODUCTION

The surgical treatment of spheno-orbital meningioma (SOM) is challenging. In addition to anatomical constraints that lead to a difficult resection, the reconstruction of the resulting defect is demanding. Uniform recommendations concerning the best reconstruction technique are not available in the existing literature. We propose a novel two-piece concept for reconstructing post-ablative defects using patient-specific implants.

MATERIAL AND METHODS

Between 2018 and 2021, seven patients underwent SOM resection using two digitally planned patient-specific implants for orbit and skull reconstruction. To analyze the accuracy of the reconstruction, preoperative plans were merged with postoperative data sets. The clinical outcome was evaluated by comparing the pre- and postoperative exophthalmos index (EI).

RESULTS

In all cases, adequate reconstruction and a satisfactory match between the final implant position and preoperative planning were achieved. The EI was reduced in all cases from a mean of 1.27 to 1.09 (p = 0.003).

CONCLUSIONS

The proposed concept of a two-piece reconstruction after SOM resection is an excellent way to manage the concern around post-ablative defects. The current technical conditions allow for a precise, safe, and predictable reconstruction.

Long-Term Follow-Up of Pediatric Patients with Dyskinetic Cerebral Palsy and Deep Brain Stimulation

BACKGROUND

Deep brain stimulation (DBS) has been increasingly used in the management of dyskinetic cerebral palsy (DCP). Data on long-term effects and the safety profile are rare.

OBJECTIVES

We assessed the efficacy and safety of pallidal DBS in pediatric patients with DCP.

METHODS

The STIM-CP trial was a prospective, single-arm, multicenter study in which patients from the parental trial agreed to be followed-up for up to 36 months. Assessments included motor and non-motor domains.

RESULTS

Of the 16 patients included initially, 14 (mean inclusion age 14 years) were assessed. There was a significant change in the (blinded) ratings of the total Dyskinesia Impairment Scale at 36 months. Twelve serious adverse events (possibly) related to treatment were documented.

CONCLUSION

DBS significantly improved dyskinesia, but other outcome parameters did not change significantly. Investigations of larger homogeneous cohorts are needed to further ascertain the impact of DBS and guide treatment decisions in DCP. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Isolated Cervical Dystonia: Diagnosis and Classification

This document presents a consensus on the diagnosis and classification of isolated cervical dystonia (iCD) with a review of proposed terminology. The International Parkinson and Movement Disorder Society Dystonia Study Group convened a panel of experts to review the main clinical and diagnostic issues related to iCD and to arrive at a consensus on diagnostic criteria and classification. These criteria are intended for use in clinical research, but also may be used to guide clinical practice. The benchmark is expert clinical observation and evaluation. The criteria aim to systematize the use of terminology as well as the diagnostic process, to make it reproducible across centers and applicable by expert and non-expert clinicians. Although motor abnormalities remain central, increasing recognition has been given to nonmotor manifestations, which are incorporated into the current criteria. Three iCD presentations are described in some detail: idiopathic (focal or segmental) iCD, genetic iCD, and acquired iCD. The relationship between iCD and isolated head tremor is also reviewed. Recognition of idiopathic iCD has two levels of certainty, definite or probable, supported by specific diagnostic criteria. Although a probable diagnosis is appropriate for clinical practice, a higher diagnostic level may be required for specific research studies. The consensus retains elements proven valuable in previous criteria and omits aspects that are no longer justified, thereby encapsulating diagnosis according to current knowledge. As understanding of iCD expands, these criteria will need continuous revision to accommodate new advances. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Neuroimaging-based analysis of DBS outcomes in pediatric dystonia: Insights from the GEPESTIM registry

INTRODUCTION

Deep brain stimulation (DBS) is an established treatment in patients of various ages with pharmaco-resistant neurological disorders. Surgical targeting and postoperative programming of DBS depend on the spatial location of the stimulating electrodes in relation to the surrounding anatomical structures, and on electrode connectivity to a specific distribution pattern within brain networks. Such information is usually collected using group-level analysis, which relies on the availability of normative imaging resources (atlases and connectomes). Analysis of DBS data in children with debilitating neurological disorders such as dystonia would benefit from such resources, especially given the developmental differences in neuroimaging data between adults and children. We assembled pediatric normative neuroimaging resources from open-access datasets in order to comply with age-related anatomical and functional differences in pediatric DBS populations. We illustrated their utility in a cohort of children with dystonia treated with pallidal DBS. We aimed to derive a local pallidal sweetspot and explore a connectivity fingerprint associated with pallidal stimulation to exemplify the utility of the assembled imaging resources.

METHODS

An average pediatric brain template (the MNI brain template 4.5-18.5 years) was implemented and used to localize the DBS electrodes in 20 patients from the GEPESTIM registry cohort. A pediatric subcortical atlas, analogous to the DISTAL atlas known in DBS research, was also employed to highlight the anatomical structures of interest. A local pallidal sweetspot was modeled, and its degree of overlap with stimulation volumes was calculated as a correlate of individual clinical outcomes. Additionally, a pediatric functional connectome of 100 neurotypical subjects from the Consortium for Reliability and Reproducibility was built to allow network-based analyses and decipher a connectivity fingerprint responsible for the clinical improvements in our cohort.

RESULTS

We successfully implemented a pediatric neuroimaging dataset that will be made available for public use as a tool for DBS analyses. Overlap of stimulation volumes with the identified DBS-sweetspot model correlated significantly with improvement on a local spatial level (R = 0.46, permuted p = 0.019). The functional connectivity fingerprint of DBS outcomes was determined to be a network correlate of therapeutic pallidal stimulation in children with dystonia (R = 0.30, permuted p = 0.003).

CONCLUSIONS

Local sweetspot and distributed network models provide neuroanatomical substrates for DBS-associated clinical outcomes in dystonia using pediatric neuroimaging surrogate data. Implementation of this pediatric neuroimaging dataset might help to improve the practice and pave the road towards a personalized DBS-neuroimaging analyses in pediatric patients.

Proinflammatory macrophage activation by the polysialic acid-Siglec-16 axis is linked to increased survival of glioblastoma patients

PURPOSE

Interactions with tumor-associated microglia and macrophages (TAM) are critical for glioblastoma progression. Polysialic acid (polySia) is a tumor-associated glycan, but its frequency of occurrence and its prognostic value in glioblastoma are disputed. Through interactions with the opposing immune receptors Siglec-11 and Siglec-16, polySia is implicated in the regulation of microglia and macrophage activity. However, due to a nonfunctional SIGLEC16P allele, SIGLEC16 penetrance is less than 40%. Here, we explored possible consequences of SIGLEC16 status and tumor cell-associated polySia on glioblastoma outcome.

EXPERIMENTAL DESIGN

FFPE specimens of two independent cohorts with 70 and 100 newly diagnosed glioblastoma patients were retrospectively analyzed for SIGLEC16 and polySia status in relation to overall survival. Inflammatory TAM activation was assessed in tumors, in heterotypic tumor spheroids consisting of polySia-positive glioblastoma cells and Siglec-16-positive or -negative macrophages, and by exposing Siglec-16-positive or -negative macrophages to glioblastoma cell-derived membrane fractions.

RESULTS

Overall survival of SIGLEC16 carriers with polySia-positive tumors was increased. Consistent with proinflammatory Siglec-16 signaling, levels of TAM positive for the M2 marker CD163 were reduced, whereas the M1 marker CD74 and TNF expression were increased, and CD8+ T cells enhanced in SIGLEC16 polySia double-positive tumors. Correspondingly, TNF production was elevated in heterotypic spheroid cultures with Siglec-16-expressing macrophages. Furthermore, a higher, mainly M1-like cytokine release and activating immune signaling was observed in SIGLEC16-positive as compared to SIGLEC16-negative macrophages confronted with glioblastoma cell-derived membranes.

CONCLUSIONS

Collectively, these results strongly suggest that proinflammatory TAM activation causes the better outcome in glioblastoma patients with a functional polySia-Siglec-16 axis.

The Chiari malformations: a bibliometric analysis of the 100 most cited papers

OBJECTIVE

The Chiari malformations present heterogeneous entities, raising many questions regarding their natural history, pathophysiology, treatment options and prognosis. Bibliometric analyses have emerged as a method to assess the impact of articles in current clinical practice.

METHODS

The most cited articles were identified via Scopus library by using the keywords "Chiari", "Arnold-Chiari" and "Chiari malformation". The 100 most cited articles were then assembled and analyzed in detail.

RESULTS

The top 100 articles yielded a mean of 155,28 citations per article, ranging from 87 to 896 citations, and from 1,63 to 38,96 per year. Years of publications ranged from 1950 to 2015. Oakes was the most cited author (n=7), followed by Tubbs, and Milhorat. The country with the highest cited articles was the United States (n=63), followed by the United Kingdom (n=6), Italy (n=5), Spain (n=5), Japan (n=4), and Germany (n=3). Neurosurgery is the journal with most highly cited articles (n=21), followed by the Journal of Neurosurgery (n=19). The majority of articles focused on Chiari malformation type I (n=83). The topic discussed most often was imaging (n=63), followed by the evaluation of treatment outcome (n=58), clinical signs and symptoms (n=57), and the role of surgery (n=56).

CONCLUSIONS

The present bibliometric analysis provides a succinct appraisal of the most cited articles concerning Chiari malformation, allowing a deeper insight in this area and its main influential articles with their impact on current clinical practice and future research.

Deep brain stimulation for hemidystonia: A meta-analysis with individual patient data

BACKGROUND

Deep brain stimulation (DBS) is now well established for the treatment of dystonic movement disorders. There is limited data, however, on the efficacy of DBS in hemidystonia. This meta-analysis aims to summarize the published reports on DBS for hemidystonia of different etiologies, to compare different stimulation targets, and to evaluate clinical outcome.

METHODS

A systematic literature review was performed on PubMed, Embase and Web of Science to identify appropriate reports. The primary outcome variables were the improvement in the Burke-Fahn-Marsden Dystonia Rating Scale movement (BFMDRS-M) and disability (BFMDRS-D) scores for dystonia.

RESULTS

Twenty-two reports (39 patients; 22 with pallidal stimulation, 4 with subthalamic stimulation, 3 with thalamic stimulation, and 10 with combined target stimulation) were included. Mean age at surgery was 26.8 years. Mean follow-up time was 31.72 months. An overall mean improvement of 40% in the BFMDRS-M score was achieved (range 0%-94%), which was paralleled by a mean improvement of 41% in the BFMDRS-D score. When considering a 20% cut-off for improvement, 23/39 patients (59%) would qualify as responders. Hemidystonia due to anoxia did not significantly improve with DBS. Several limitations of the results must be considered, most importantly the low level of evidence and the small number of reported cases.

CONCLUSION

Based on the results of the current analysis, DBS can be considered as a treatment option for hemidystonia. The posteroventral lateral GPi is the target used most often. More research is needed to understand the variability in outcome and to identify prognostic factors.

Advances in Technical Aspects of Deep Brain Stimulation Surgery

BACKGROUND

Deep brain stimulation has become an established technology for the treatment of patients with a wide variety of conditions, including movement disorders, psychiatric disorders, epilepsy, and pain. Surgery for implantation of DBS devices has enhanced our understanding of human physiology, which in turn has led to advances in DBS technology. Our group has previously published on these advances, proposed future developments, and examined evolving indications for DBS.

SUMMARY

The crucial roles of structural MR imaging pre-, intra-, and post-DBS procedure in target visualization and confirmation of targeting are described, with discussion of new MR sequences and higher field strength MRI enabling direct visualization of brain targets. The incorporation of functional and connectivity imaging in procedural workup and their contribution to anatomical modelling is reviewed. Various tools for targeting and implanting electrodes, including frame-based, frameless, and robot-assisted, are surveyed, and their pros and cons are described. Updates on brain atlases and various software used for planning target coordinates and trajectories are presented. The pros and cons of asleep versus awake surgery are discussed. The role and value of microelectrode recording and local field potentials are described, as well as the role of intraoperative stimulation. Technical aspects of novel electrode designs and implantable pulse generators are presented and compared.

Pallidal Beta Activity Is Linked to Stimulation-Induced Slowness in Dystonia

BACKGROUND

Pallidal deep brain stimulation (DBS) effectively alleviates symptoms in dystonia patients, but may induce movement slowness as a side-effect. In Parkinson's disease, hypokinetic symptoms have been associated with increased beta oscillations (13-30 Hz). We hypothesize that this pattern is symptom-specific, thus accompanying DBS-induced slowness in dystonia.

METHODS

In 6 dystonia patients, pallidal rest recordings with a sensing-enabled DBS device were performed and tapping speed was assessed using marker-less pose estimation over 5 time points following cessation of DBS.

RESULTS

After cessation of pallidal stimulation, movement speed increased over time (P < 0.01). A linear mixed-effects model revealed that pallidal beta activity explained 77% of the variance in movement speed across patients (P = 0.01).

CONCLUSIONS

The association between beta oscillations and slowness across disease entities provides further evidence for symptom-specific oscillatory patterns in the motor circuit. Our findings might help DBS therapy improvements, as DBS-devices able to adapt to beta oscillations are already commercially available. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

The intralaminar thalamus: a review of its role as a target in functional neurosurgery

The intralaminar thalamus, in particular the centromedian-parafascicular complex, forms a strategic node between ascending information from the spinal cord and brainstem and forebrain circuitry that involves the cerebral cortex and basal ganglia. A large body of evidence shows that this functionally heterogeneous region regulates information transmission in different cortical circuits, and is involved in a variety of functions, including cognition, arousal, consciousness and processing of pain signals. Not surprisingly, the intralaminar thalamus has been a target area for (radio)surgical ablation and deep brain stimulation (DBS) in different neurological and psychiatric disorders. Historically, ablation and stimulation of the intralaminar thalamus have been explored in patients with pain, epilepsy and Tourette syndrome. Moreover, DBS has been used as an experimental treatment for disorders of consciousness and a variety of movement disorders. In this review, we provide a comprehensive analysis of the underlying mechanisms of stimulation and ablation of the intralaminar nuclei, historical clinical evidence, and more recent (experimental) studies in animals and humans to define the present and future role of the intralaminar thalamus as a target in the treatment of neurological and psychiatric disorders.

Case report: Pallidal deep brain stimulation for treatment of tardive dystonia/dyskinesia secondary to chronic metoclopramide medication

Objectives

Tardive dystonia/dyskinesia (TDD) occurs as a side effect of anti-dopaminergic drugs, including metoclopramide, and is often refractory to medication. While pallidal deep brain stimulation (DBS) has become an accepted treatment for TDD secondary to neuroleptic medication, there is much less knowledge about its effects on metoclopramide-induced TDD.

Methods

We present the case of a woman with metoclopramide-induced TDD, whose symptoms were initially misjudged as "functional." After 8 years of ineffective medical treatments, she received bilateral implantation of quadripolar electrodes into the posteroventral lateral globus pallidus internus (GPi).

Results

GPi DBS led to significant symptom reduction [Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS) motor score 24/44 at admission and 7/44 at discharge]. Chronic stimulation led to full recovery from TDD symptoms 9 years after surgery. The BFMDRS motor score decreased to 0.5 (98% improvement).

Discussion

Pallidal DBS may result in sustained improvement of TDD secondary to chronic metoclopramide intake in the long term.

Clinical Features of Idiopathic Normal Pressure Hydrocephalus: Critical Review of Objective Findings

Background

Idiopathic normal pressure hydrocephalus (iNPH) is characterized by the classic clinical triad of gait, cognitive, and urinary dysfunction, albeit incomplete in a relevant proportion of patients. The clinical findings and evolution of these symptoms have been variably defined in the literature.

Objectives

To evaluate how the phenomenology has been defined, assessed, and reported, we performed a critical review of the existing literature discussing the phenomenology of iNPH. The review also identified the instrumental tests most frequently used and the evolution of clinical and radiologic findings.

Methods

The review was divided into 3 sections based on gait, cognitive, and urinary dysfunction. Each section performed a literature search using the terms "idiopathic normal pressure hydrocephalus" (iNPH), with additional search terms used by each section separately. The number of articles screened, duplicates, those meeting the inclusion criteria, and the number of articles excluded were recorded. Findings were subsequently tallied and analyzed.

Results

A total of 1716 articles with the aforementioned search criteria were identified by the 3 groups. A total of 81 full-text articles were reviewed after the elimination of duplicates, articles that did not discuss phenomenological findings or instrumental testing of participants with iNPH prior to surgery, and articles with fewer than 10 participants.

Conclusions

"Wide-based gait" was the most common gait dysfunction identified. Cognitive testing varied significantly across articles, and ultimately a specific cognitive profile was not identified. Urodynamic testing found detrusor overactivity and "overactive bladder" as the most common symptom of urinary dysfunction.

Severity Assessment of Complex and Repeated Intracranial Surgery in Rats

INTRODUCTION

Evidence-based grading of the impact of intracranial surgery on rat's well-being is important for ethical and legal reasons. We assessed the severity of complex and repeated intracranial surgery in a 6-hydroxydopamine (6-OHDA) Parkinson's rat model with subsequent intracranial electrode implantation and in an intracranial tumor model with subsequent resection.

METHODS

Stereotactic surgery was performed in adult male rats with the same general anesthesia and perioperative pain management. In Parkinson's model, Sprague Dawley rats received unilateral injection of 6-OHDA (n = 11) or vehicle (n = 7) into the medial forebrain bundle as first operation (1st OP). After four weeks, neural electrodes were implanted in all rats as second operation (2nd OP). For tumor formation, BDIX/UlmHanZtm rats (n = 8) received frontocortical injection of BT4Ca cells as 1st OP, followed by tumor resection as 2nd OP after one week. Multiple measures severity assessment was done two days before and four days after surgery in all rats, comprising clinical scoring, body weight, and detailed behavioral screening. To include a condition with a known burden, rats with intracranial tumors were additionally assessed up to a predefined humane endpoint that has previously been classified as "moderate".

RESULTS

After the 1st OP, only 6-OHDA injection resulted in transient elevated clinical scores, a mild long-lasting weight reduction, and motor disturbances. After the second surgery, body weight was transiently reduced in all groups. All other parameters showed variable results. Principal component analysis showed a separation from the preoperative state driven by motor-related parameters after 6-OHDA injection, while separation after electrode implantation and more clearly after tumor resection was driven by pain-related parameters, although not reaching the level of the humane endpoint of our tumor model.

CONCLUSION

Overall, cranial surgery of different complexity only transiently and rather mildly affects rat's well-being. Multiple measures assessment allows the differentiation of model-related motor disturbances in Parkinson's model from potentially pain-related conditions after tumor resection and electrode implantation.

Stereotactic biopsy of a brain lesion caused by hormographiella aspergillata

Background

Invasive fungal infections are an increasing problem in immunosuppressed patients. In patients with the central nervous system involvement, there is a high case fatality rate. There is a very limited experience with infections caused by Hormographiella aspergillata (HA) in such cases and most often diagnosis is only confirmed postmortem.

Case Description

We report the case of a 53-year-old woman with acute myeloid leukemia. After primary therapy with daunorubicin, cytarabine, and gemtuzumab ozogamicin, the patient developed pneumonia and later neurological symptoms caused by multiple gadolinium-enhancing brain lesions in magnetic resonance imaging (MRI). Stereotactic biopsy of a frontal precentral lesion was performed and revealed HA infection. The patient died in the further course secondary to cardiopulmonary problems.

Conclusion

Stereotactic biopsy is a safe way to establish the diagnosis of unclear lesions such as HA infection. We recommend to perform stereotactic biopsy early in immunocompromised patients with brain lesions to guide further treatment.

Routine postoperative admission to the neurocritical intensive care unit after microvascular decompression: necessary or can it be abandoned?

Postoperative neurocritical intensive care unit (NICU) admission of patients who underwent craniotomy for close observation is common practice. In this study, we performed a comparative analysis to determine if there is a real need for NICU admission after microvascular decompression (MVD) for cranial nerve disorders or whether it may be abandoned. The present study evaluates a consecutive series of 236 MVD surgeries performed for treatment of trigeminal neuralgia (213), hemifacial spasm (17), vagoglossopharyngeal neuralgia (2), paroxysmal vertigo (2), and pulsatile tinnitus (2). All patients were operated by the senior surgeon according to a standard protocol over a period of 12 years. Patients were admitted routinely to NICU during the first phase of the study (phase I), while in the second phase (phase II), only patients with specific indications would go to NICU. While 105 patients (44%) were admitted to NICU postoperatively (phase I), 131 patients (56%) returned to the ward after a short stay in a postanaesthesia care unit (PACU) (phase II). Specific indications for NICU admission in phase I were pneumothorax secondary to central venous catheter insertion (4 patients), AV block during surgery, low blood oxygen levels after extubation, and postoperative dysphagia and dysphonia (1 patient, respectively). There were no significant differences in the distribution of ASA scores or the presence of cardiac and pulmonary comorbidities like congestive heart failure, arterial hypertension, or chronic obstructive pulmonary disease between groups. There were no secondary referrals from PACU to NICU. Our study shows that routine admission of patients after eventless MVD to NICU does not provide additional value. NICU admission can be restricted to patients with specific indications. When MVD surgery is performed in experienced hands according to a standard anaesthesia protocol, clinical observation on a neurosurgical ward is sufficient to monitor the postoperative course. Such a policy results in substantial savings of costs and human resources.

Mechanical Stability of Nano-Coatings on Clinically Applicable Electrodes, Generated by Electrophoretic Deposition

The mechanical stability of implant coatings is crucial for medical approval and transfer to clinical applications. Here, electrophoretic deposition (EPD) is a versatile coating technique, previously shown to cause significant post-surgery impedance reduction of brain stimulation platinum electrodes. However, the mechanical stability of the resulting coating has been rarely systematically investigated. In this work, pulsed-DC EPD of laser-generated platinum nanoparticles (PtNPs) on Pt-based, 3D neural electrodes is performed and the in vitro mechanical stability is examined using agarose gel, adhesive tape, and ultrasonication-based stress tests. EPD-generated coatings are highly stable inside simulated brain environments represented by agarose gel tests as well as after in vivo stimulation experiments. Electrochemical stability of the NP-modified surfaces is tested via cyclic voltammetry and that multiple scans may improve coating stability could be verified, indicated by higher signal stability following highly invasive adhesive tape stress tests. The brain sections post neural stimulation in rats are analyzed via laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS). Measurements reveal higher levels of Pt near the region stimulated with coated electrodes, in comparison to uncoated controls. Even though local concentrations in the vicinity of the implanted electrode are elevated, the total Pt mass found is below systemic toxicologically relevant concentrations.

Processing of auditory information in forebrain regions after hearing loss in adulthood: Behavioral and electrophysiological studies in a rat model

Background

Hearing loss was proposed as a factor affecting development of cognitive impairment in elderly. Deficits cannot be explained primarily by dysfunctional neuronal networks within the central auditory system. We here tested the impact of hearing loss in adult rats on motor, social, and cognitive function. Furthermore, potential changes in the neuronal activity in the medial prefrontal cortex (mPFC) and the inferior colliculus (IC) were evaluated.

Materials and methods

In adult male Sprague Dawley rats hearing loss was induced under general anesthesia with intracochlear injection of neomycin. Sham-operated and naive rats served as controls. Postsurgical acoustically evoked auditory brainstem response (ABR)-measurements verified hearing loss after intracochlear neomycin-injection, respectively, intact hearing in sham-operated and naive controls. In intervals of 8 weeks and up to 12 months after surgery rats were tested for locomotor activity (open field) and coordination (Rotarod), for social interaction and preference, and for learning and memory (4-arms baited 8-arms radial maze test). In a final setting, electrophysiological recordings were performed in the mPFC and the IC.

Results

Locomotor activity did not differ between deaf and control rats, whereas motor coordination on the Rotarod was disturbed in deaf rats (P &lt; 0.05). Learning the concept of the radial maze test was initially disturbed in deaf rats (P &lt; 0.05), whereas retesting every 8 weeks did not show long-term memory deficits. Social interaction and preference was also not affected by hearing loss. Final electrophysiological recordings in anesthetized rats revealed reduced firing rates, enhanced irregular firing, and reduced oscillatory theta band activity (4–8 Hz) in the mPFC of deaf rats as compared to controls (P &lt; 0.05). In the IC, reduced oscillatory theta (4–8 Hz) and gamma (30–100 Hz) band activity was found in deaf rats (P &lt; 0.05).

Conclusion

Minor and transient behavioral deficits do not confirm direct impact of long-term hearing loss on cognitive function in rats. However, the altered neuronal activities in the mPFC and IC after hearing loss indicate effects on neuronal networks in and outside the central auditory system with potential consequences on cognitive function.

Heterozygous UCHL1 loss-of-function variants cause a neurodegenerative disorder with spasticity, ataxia, neuropathy, and optic atrophy

PURPOSE

Biallelic variants in UCHL1 have been associated with a progressive early-onset neurodegenerative disorder, autosomal recessive spastic paraplegia type 79. In this study, we investigated heterozygous UCHL1 variants on the basis of results from cohort-based burden analyses.

METHODS

Gene-burden analyses were performed on exome and genome data of independent cohorts of patients with hereditary ataxia and spastic paraplegia from Germany and the United Kingdom in a total of 3169 patients and 33,141 controls. Clinical data of affected individuals and additional independent families were collected and evaluated. Patients' fibroblasts were used to perform mass spectrometry-based proteomics.

RESULTS

UCHL1 was prioritized in both independent cohorts as a candidate gene for an autosomal dominant disorder. We identified a total of 34 cases from 18 unrelated families, carrying 13 heterozygous loss-of-function variants (15 families) and an inframe insertion (3 families). Affected individuals mainly presented with spasticity (24/31), ataxia (28/31), neuropathy (11/21), and optic atrophy (9/17). The mass spectrometry-based proteomics showed approximately 50% reduction of UCHL1 expression in patients' fibroblasts.

CONCLUSION

Our bioinformatic analysis, in-depth clinical and genetic workup, and functional studies established haploinsufficiency of UCHL1 as a novel disease mechanism in spastic ataxia.

Validity of the Early Functional Ability scale (EFA) among critically ill patients undergoing early neurological rehabilitation

Background

A reliable assessment of the functional abilities of patients after severe brain damage is crucial for valid prognostication and treatment decisions, but most clinical scales are of limited use among this specific group of patients.

Aim

The present study investigates the usefulness of the Early Functional Ability (EFA) scale, which determines the functional abilities of severely impaired patients.

Methods

Critically ill patients consecutively admitted to early neurological rehabilitation were screened for eligibility. We assessed the correlation between the EFA scale and (i) the Early Rehabilitation Barthel Index (ERBI), and (ii) the Coma Recovery Scale-Revised (CRS-R). The 1-year outcome on the Glasgow Outcome Scale-extended (GOSE) was used to examine the predictive validity. Demographical and medical variables were entered into univariate and multivariate binary regression models to identify independent predictors of 1-year outcome.

Results

Two hundred fifty-seven patients (168 men) with a median age of 62 years (IQR = 51–75) were enrolled. The correlation of the EFA scale with the CRS-R was high but low with the ERBI upon admission. Multivariate regression analysis yielded the vegetative subscale of the EFA scale as the only independent predictor for the 1-year outcome of patients admitted to early neurological rehabilitation.

Conclusions

This study shows a high correlation of the EFA scale with the CRS-R but a weak correlation with the ERBI in patients with low functional abilities. With improving patient abilities, these correlations were partly reversed. Thus, the EFA scale is a useful tool to assess the functional abilities and the prognosis of critically ill patients adequately and may be more feasible than other scales.

Are Transventricular Approaches Associated With Increased Hemorrhage? A Comparative Study in a Series of 624 Deep Brain Stimulation Surgeries

BACKGROUND

Deep brain stimulation (DBS) surgery has advanced tremendously, for both clinical applications and technology. Although DBS surgery is an overall safe procedure, rare side effects, in particular, hemorrhage, may result in devastating consequences. Although there are certain advantages with transventricular trajectories, it has been reasoned that avoidance of such trajectories would likely reduce hemorrhage.

OBJECTIVE

To investigate the possible impact of a transventricular trajectory as compared with a transcerebral approach on the occurrence of symptomatic and asymptomatic hemorrhage after DBS electrode placement.

METHODS

Retrospective evaluation of 624 DBS surgeries in 582 patients, who underwent DBS surgery for movement disorders, chronic pain, or psychiatric disorders. A stereotactic guiding cannula was routinely used for DBS electrode insertion. All patients had postoperative computed tomography scans within 24 hours after surgery.

RESULTS

Transventricular transgression was identified in 404/624 DBS surgeries. The frequency of hemorrhage was slightly higher in transventricular than in transcerebral DBS surgeries (15/404, 3.7% vs 6/220, 2.7%). While 7/15 patients in the transventricular DBS surgery group had a hemorrhage located in the ventricle, 6 had an intracerebral hemorrhage along the electrode trajectory unrelated to transgression of the ventricle and 2 had a subdural hematoma. Among the 7 patients with a hemorrhage located in the ventricle, only one became symptomatic. Overall, a total of 7/404 patients in the transventricular DBS surgery group had a symptomatic hemorrhage, whereas the hemorrhage remained asymptomatic in all 6/220 patients in the transcerebral DBS surgery group.

CONCLUSION

Transventricular approaches in DBS surgery can be performed safely, in general, when special precautions such as using a guiding cannula are routinely applied.

Surgical treatment of selected tumors via the navigated minimally invasive presigmoidal suprabulbar infralabyrinthine approach without rerouting of the facial nerve

The feasibility of a novel skull base approach - the navigated minimally invasive presigmoidal suprabulbar infralabyrinthine approach (NaMIPSI-A) without rerouting of the fallopian canal for selected jugular foramen tumors (JFTs) - has been demonstrated in a neuroanatomical laboratory study. Here, we present our clinical experience with the NaMIPSI-A for selected JFTs, with a particular focus on its efficacy and safety. All patients with JFTs who were treated via the NaMIPSI-A were included in this study. The JFTs were classified according to a modified Fisch classification. The neurological and neuroradiological outcome, the extent of tumor resection, and the approach-related morbidity were examined. Five patients (two women, three men; mean age 57 years, range 48-65) were available. According to the modified Fisch classification, two JFTs were graded as C1, one as De1, and two as De2. Gross total resection (GTR) was achieved in three patients and near-total resection (NTR) in two. Postsurgically, no new neurological deficits and no approach-related morbidity and mortality occurred. One case with a postoperative cerebrospinal fluid leak was managed successfully with lumbar drainage. During the follow-up period (mean 67.6 months, range 12-119 months), tumor recurrence was noted in the NTR group but not in the GTR group. The NaMIPSI-A to the jugular foramen without rerouting of the fallopian canal is highly valuable for selected tumors of the jugular foramen. It is less invasive than other skull base approaches, and it allows safe and complete tumor removal in appropriate patients.

Effect of mannitol on platelet function during elective craniotomy in adult patients with brain tumor

BACKGROUND

Mannitol is used in the treatment of raised intracranial pressure (ICP). The aim of this study was to investigate whether mannitol (MAN) leads to a relevant deterioration in platelet function in routine neurosurgical procedures.

METHODS

Thirty-eight patients undergoing elective craniotomy due to a brain tumor with elevated ICP were included. After induction of anaesthesia a blood sample was taken (T1). The patients then received 1 g-kg-1 MAN within 30 minutes. The second blood sample (T2) was obtained 60 minutes after T1. Blood samples were examined by means of aggregometry (Multiplate®) and PFA-100® tests.

RESULTS

No patient had clinical signs of increased bleeding. We could not find any deterioration in the aggregometry using Multiplate®, neither in the adenosinediphosphate (ADP), the arachidonic acid (ASPI), or the thrombin receptor activating protein (TRAP) test. PFA-100® closing times (cT) showed a significant prolongation between T1 and T2: collagen/adenosindiphosphate (COL/ADP) test 79s [70/99] and 91s [81/109]; p=0.002); collagen/epinephrine (COL/EPI) test 109s [92/129] and 122s [94/159]; p=0.0004). A subgroup analysis showed that the patients who received isotonic balanced infusions only, had no prolongation of cT, whereas the patients who received additionally gelatine solution had a significant prolongation.

COL/ADP

78s [70/98] and 91s [82/133]; p=0.0004). COL/EPI: test 111s [92/128] and 127s [103/146]; p=0.0026). Except for individual outliers, the measured values were in the normal range.

CONCLUSIONS

In this study, we found no clinically relevant deterioration of platelet function in neurosurgical patients with increased ICP after administration of MAN. Changes that occurred were all within normal ranges.

Sweets for my sweet: modulation of the limbic system drives salience for sweet foods after deep brain stimulation in Parkinson's disease

BACKGROUND

An increase in body weight is observed in the majority of patients with Parkinson's disease (PD) who undergo deep brain stimulation (DBS) of the subthalamic nucleus (STN) although the mechanisms are unclear.

OBJECTIVES

To identify the stimulation-dependent effects on reward-associated and attention-associated neural networks and to determine whether these alterations in functional connectivity are associated with the local impact of DBS on different STN parcellations.

METHODS

We acquired functional task-related MRI data from 21 patients with PD during active and inactive STN DBS and 19 controls while performing a food viewing paradigm. Electrode placement in the STN was localised using a state-of-the-art approach. Based on the 3D model, the local impact of STN DBS was estimated.

RESULTS

STN DBS resulted in a mean improvement of motor function of 22.6%±15.5% (on medication) and an increase of body weight of ~4 kg within 2 years of stimulation. DBS of the limbic proportion of the STN was associated with body weight gain and an increased functional connectivity within the salience network and at the same time with a decreased activity within the reward-related network in the context of sweet food images.

CONCLUSIONS

Our findings indicate increased selective attention for high-caloric foods and a sweet food seeking-like behaviour after DBS particularly when the limbic proportion of the STN was stimulated.