Turning the operating room into a mixed-reality environment: a prospective clinical investigation for cerebral aneurysm clipping.

OBJECTIVE: The overall aim of this study was to demonstrate the potential benefit of a novel mixed-reality-head-mounted display (MR-HMD) on the spatial orientation of surgeons. METHODS: In a prospective clinical investigation, the authors applied for the first time a new multicamera navigation technology in an operating room setting that allowed them to directly compare MR-HMD navigation to standard monitor navigation. In the study, which included 14 patients with nonruptured middle cerebral artery aneurysms, the authors investigated how intuitively and effectively surgical instruments could be guided in 5 different visual navigation conditions. RESULTS: The authors demonstrate that multicamera tracking can be reliably integrated in a clinical setting (usability score 1.12 ± 0.31). Moreover, the technology captures large volumes of the operating room, allowing the team to track and integrate different devices and instruments, including MR-HMDs. Directly comparing mixed-reality navigation to standard monitor navigation revealed a significantly improved intuition in mixed reality, leading to navigation times that were twice as fast (2.1×, p ≤ 0.01). Despite the enhanced speed, the same targeting accuracy (approximately 2.5 mm, freehand tool use) in comparison to monitor navigation could be observed. Intraoperative planning strategies with mixed reality clearly outperformed classic preoperative planning: surgeons scored the mixed-reality plan as the best trajectory in 63% of the cases (chance level 33%). CONCLUSIONS: The incorporation of mixed reality in neurosurgical operations marks a significant advancement in the field. The use of mixed reality in brain surgery enhances the spatial awareness of surgeons, enabling more instinctive and precise surgical interventions. This technological integration promises to refine the execution of complex procedures without compromising accuracy.

Open Microsurgical Cerebral Aneurysm Treatment After Failed Endovascular Therapy: An Evaluation of Aneurysm Treatment Frequencies in All Neurovascular Centers Across Austria and the Czech Republic Over 20 Years.

BACKGROUND AND OBJECTIVES: Endovascular treatment of cerebral aneurysms has tremendously advanced over the past decades. Nevertheless, aneurysm residual and recurrence remain challenges after embolization. The objective of this study was to elucidate the portion of embolized aneurysms requiring open surgery and evaluate whether newer endovascular treatments have changed the need for open surgery after failed embolization. METHODS: All 15 cerebrovascular centers in Austria and the Czech Republic provided overall aneurysm treatment frequency data and retrospectively reviewed consecutive cerebral aneurysms treated with open surgical treatment after failure of embolization from 2000 to 2022. All endovascular modalities were included. RESULTS: On average, 1362 aneurysms were treated annually in the 2 countries. The incidence increased from 0.006% in 2005 to 0.008% in 2020 in the overall population. Open surgery after failed endovascular intervention was necessary in 128 aneurysms (0.8%), a proportion that remained constant over time. Subarachnoid hemorrhage was the initial presentation in 70.3% of aneurysms. The most common location was the anterior communicating artery region (40.6%), followed by the middle cerebral artery (25.0%). The median diameter was 6 mm (2-32). Initial endovascular treatment included coiling (107 aneurysms), balloon-assist (10), stent-assist (4), intrasaccular device (3), flow diversion (2), and others (2). Complete occlusion after initial embolization was recorded in 40.6%. Seventy-one percent of aneurysms were operated within 3 years after embolization. In 7%, the indication for surgery was (re-)rupture and, in 88.3%, reperfusion. Device removal was performed in 16.4%. Symptomatic intraoperative and postoperative complications occurred in 10.2%. Complete aneurysm occlusion after open surgery was achieved in 94%. CONCLUSION: Open surgery remains a rare indication for cerebral aneurysms after failed endovascular embolization even in the age of novel endovascular technology, such as flow diverters and intrasaccular devices. Regardless, it is mostly performed for ruptured aneurysms initially treated with primary coiling that are in the anterior circulation.

Sex-dependent characteristics and outcomes after clipping of unruptured intracranial aneurysms: a multicenter propensity score-matched study.

OBJECTIVE: Disparities in the epidemiology and growth rates of aneurysms between the sexes are known. However, little is known about sex-dependent outcomes after microsurgical clipping of unruptured intracranial aneurysms (UIAs). The aim of this study was to examine sex differences in characteristics and outcomes after microsurgical clipping of UIAs and to perform a propensity score-matched analysis using an international multicenter cohort. METHODS: This retrospective cohort study involved the participation of 15 centers spanning four continents. It included adult patients who underwent clipping of UIAs between January 2016 and December 2020. Patients were stratified according to their sex and analyzed for differences in morbidities and aneurysm characteristics. Based on this stratification, female patients were matched to male patients in a 1:1 ratio with a caliper width of 0.1 using propensity score matching. Endpoints included postoperative complications, neurological performance, and aneurysm occlusion at discharge and 24 months after clip placement. RESULTS: A total of 2245 patients with a mean age of 57.3 (range 20-87) years were included. Of these patients, 1675 (74.6%) were female. Female patients were significantly older (mean 57.6 vs 56.4 years, p = 0.03) but had fewer comorbidities. Aneurysms of the internal carotid artery (7.1% vs 4.2%), posterior communicating artery (6.9% vs 1.9%), and ophthalmic artery (6.0% vs 2.8%) were more commonly treated surgically in females, while clipping of aneurysms of the anterior communicating artery was more frequent in males (17.0% vs 25.3%; all p < 0.001). After propensity score matching, female patients were found to have had significantly fewer pulmonary complications (1.4% vs 4.2%, p = 0.01). However, general morbidity (24.5% vs 25.2%, p = 0.72) and mortality (0.5% vs 1.1%, p = 0.34), as well as neurological performance (p = 0.58), were comparable at discharge in both sexes. Lastly, rates of aneurysm occlusion at the time of discharge (95.5% vs 94.9%, p = 0.71) and 24 months after surgery (93.8% vs 96.1%, p = 0.22) did not significantly differ between male and female patients. CONCLUSIONS: Despite overall differences between male and female patients in demographics, comorbidities, and treated aneurysm location, sex did not relevantly affect surgical performance or perioperative complication rates.

Feasibility, Clinical Potential, and Limitations of Trans-Burr Hole Ultrasound for Postoperative Evaluation of Chronic Subdural Hematoma: A Prospective Pilot Study.

BACKGROUND AND OBJECTIVES: Chronic subdural hematoma (CSDH) is commonly managed through burr hole surgery. Routine follow-up using computed tomography (CT) imaging is frequently used at many institutions, contributing to significant radiation exposure. This study evaluates the feasibility, safety, and reliability of trans-burr hole sonography as an alternative postoperative imaging modality, aiming to reduce radiation exposure by decreasing the frequency of CT scans. METHODS: We conducted a prospective pilot study on 20 patients who underwent burr hole surgery for CSDH. Postoperative imaging included both CT and sonographic examinations through the burr hole. We assessed the ability to measure residual subdural fluid thickness under the burr hole sonographically compared with CT, the occurrence of complications, and the potential factors affecting sonographic image quality. The Pearson correlation coefficient was used to demonstrate relationships between CT and ultrasound and axial and coronal ultrasound. RESULTS: Sonography through the burr hole was feasible in 73.5% of cases, providing measurements of residual fluid that closely paralleled CT findings, with an average discrepancy of 1.2 mm for axial and 1.4 mm for coronal sonographic views. A strong positive correlation was found between axial and coronal ultrasound (r = 0.955), CT and axial ultrasound (r = 0.936), and CT and coronal ultrasound (r = 0.920). The primary obstacle for sonographic imaging was the presence of air within the burr hole or the subdural space, which typically resolved over time after surgery. CONCLUSION: Trans-burr hole sonography emerges as a promising technique for postoperative monitoring of CSDH, with the potential to safely reduce reliance on CT scans and associated radiation exposure in selected patients. Our results support further investigation into the extended use of sonography during the follow-up phase. Prospective multicenter studies are recommended to establish the method's efficacy and to explore strategies for minimizing air presence postsurgery.

From molecular signatures to radiomics: tailoring neurooncological strategies through forecasting of glioma growth.

OBJECTIVE: Contemporary oncological paradigms for adjuvant treatment of low- and intermediate-grade gliomas are often guided by a limited array of parameters, overlooking the dynamic nature of the disease. The authors' aim was to develop a comprehensive multivariate glioma growth model based on multicentric data, to facilitate more individualized therapeutic strategies. METHODS: Random slope models with subject-specific random intercepts were fitted to a retrospective cohort of grade II and III gliomas from the database at Kepler University Hospital (n = 191) to predict future mean tumor diameters. Deep learning-based radiomics was used together with a comprehensive clinical dataset and evaluated on an external prospectively collected validation cohort from University Hospital Zurich (n = 9). Prediction quality was assessed via mean squared prediction error. RESULTS: A mean squared prediction error of 0.58 cm for the external validation cohort was achieved, indicating very good prognostic value. The mean ± SD time to adjuvant therapy was 28.7 ± 43.3 months and 16.1 ± 14.6 months for the training and validation cohort, respectively, with a mean of 6.2 ± 5 and 3.6 ± 0.7, respectively, for number of observations. The observed mean tumor diameter per year was 0.38 cm (95% CI 0.25-0.51) for the training cohort, and 1.02 cm (95% CI 0.78-2.82) for the validation cohort. Glioma of the superior frontal gyrus showed a higher rate of tumor growth than insular glioma. Oligodendroglioma showed less pronounced growth, anaplastic astrocytoma-unlike anaplastic oligodendroglioma-was associated with faster tumor growth. Unlike the impact of extent of resection, isocitrate dehydrogenase (IDH) had negligible influence on tumor growth. Inclusion of radiomics variables significantly enhanced the prediction performance of the random slope model used. CONCLUSIONS: The authors developed an advanced statistical model to predict tumor volumes both pre- and postoperatively, using comprehensive data prior to the initiation of adjuvant therapy. Using radiomics enhanced the precision of the prediction models. Whereas tumor extent of resection and topology emerged as influential factors in tumor growth, the IDH status did not. This study emphasizes the imperative of advanced computational methods in refining personalized low-grade glioma treatment, advocating a move beyond traditional paradigms.

Microsurgical Clipping of Unruptured Anterior Circulation Aneurysms-A Global Multicenter Investigation of Perioperative Outcomes.

BACKGROUND AND OBJECTIVES: Microsurgical aneurysm repair by clipping continues to be highly important despite increasing endovascular treatment options, especially because of inferior occlusion rates. This study aimed to present current global microsurgical treatment practices and to identify risk factors for complications and neurological deterioration after clipping of unruptured anterior circulation aneurysms. METHODS: Fifteen centers from 4 continents participated in this retrospective cohort study. Consecutive patients who underwent elective microsurgical clipping of untreated unruptured intracranial aneurysm between January 2016 and December 2020 were included. Posterior circulation aneurysms were excluded. Outcome parameters were postsurgical complications and neurological deterioration (defined as decline on the modified Rankin Scale) at discharge and during follow-up. Multivariate regression analyses were performed adjusting for all described patient characteristics. RESULTS: Among a total of 2192 patients with anterior circulation aneurysm, complete occlusion of the treated aneurysm was achieved in 2089 (95.3%) patients at discharge. The occlusion rate remained stable (94.7%) during follow-up. Regression analysis identified hypertension (P < .02), aneurysm diameter (P < .001), neck diameter (P < .05), calcification (P < .01), and morphology (P = .002) as preexisting risk factors for postsurgical complications and neurological deterioration at discharge. Furthermore, intraoperative aneurysm rupture (odds ratio 2.863 [CI 1.606-5.104]; P < .01) and simultaneous clipping of more than 1 aneurysm (odds ratio 1.738 [CI 1.186-2.545]; P < .01) were shown to be associated with an increased risk of postsurgical complications. Yet, none of the surgical-related parameters had an impact on neurological deterioration. Analyzing volume-outcome relationship revealed comparable complication rates (P = .61) among all 15 participating centers. CONCLUSION: Our international, multicenter analysis presents current microsurgical treatment practices in patients with anterior circulation aneurysms and identifies preexisting and surgery-related risk factors for postoperative complications and neurological deterioration. These findings may assist in decision-making for the optimal therapeutic regimen of unruptured anterior circulation aneurysms.

Global Outcomes for Microsurgical Clipping of Unruptured Intracranial Aneurysms: A Benchmark Analysis of 2245 Cases.

BACKGROUND AND OBJECTIVES: Benchmarks represent the best possible outcome and help to improve outcomes for surgical procedures. However, global thresholds mirroring an optimal and reachable outcome for microsurgical clipping of unruptured intracranial aneurysms (UIA) are not available. This study aimed to define standardized outcome benchmarks in patients who underwent clipping of UIA. METHODS: A total of 2245 microsurgically treated UIA from 15 centers were analyzed. Patients were categorized into low- ("benchmark") and high-risk ("nonbenchmark") patients based on known factors affecting outcome. The benchmark was defined as the 75th percentile of all centers' median scores for a given outcome. Benchmark outcomes included intraoperative (eg, duration of surgery, blood transfusion), postoperative (eg, reoperation, neurological status), and aneurysm-related factors (eg, aneurysm occlusion). Benchmark cutoffs for aneurysms of the anterior communicating/anterior cerebral artery, middle cerebral artery, and posterior communicating artery were determined separately. RESULTS: Of the 2245 cases, 852 (37.9%) patients formed the benchmark cohort. Most operations were performed for middle cerebral artery aneurysms (53.6%), followed by anterior communicating and anterior cerebral artery aneurysms (25.2%). Based on the results of the benchmark cohort, the following benchmark cutoffs were established: favorable neurological outcome (modified Rankin scale ≤2) ≥95.9%, postoperative complication rate ≤20.7%, length of postoperative stay ≤7.7 days, asymptomatic stroke ≤3.6%, surgical site infection ≤2.7%, cerebral vasospasm ≤2.5%, new motor deficit ≤5.9%, aneurysm closure rate ≥97.1%, and at 1-year follow-up: aneurysm closure rate ≥98.0%. At 24 months, benchmark patients had a better score on the modified Rankin scale than nonbenchmark patients. CONCLUSION: This study presents internationally applicable benchmarks for clinically relevant outcomes after microsurgical clipping of UIA. These benchmark cutoffs can serve as reference values for other centers, patient registries, and for comparing the benefit of other interventions or novel surgical techniques.

Machine learning based outcome prediction of microsurgically treated unruptured intracranial aneurysms.

Machine learning (ML) has revolutionized data processing in recent years. This study presents the results of the first prediction models based on a long-term monocentric data registry of patients with microsurgically treated unruptured intracranial aneurysms (UIAs) using a temporal train-test split. Temporal train-test splits allow to simulate prospective validation, and therefore provide more accurate estimations of a model's predictive quality when applied to future patients. ML models for the prediction of the Glasgow outcome scale, modified Rankin Scale (mRS), and new transient or permanent neurological deficits (output variables) were created from all UIA patients that underwent microsurgery at the Kepler University Hospital Linz (Austria) between 2002 and 2020 (n = 466), based on 18 patient- and 10 aneurysm-specific preoperative parameters (input variables). Train-test splitting was performed with a temporal split for outcome prediction in microsurgical therapy of UIA. Moreover, an external validation was conducted on an independent external data set (n = 256) of the Department of Neurosurgery, University Medical Centre Hamburg-Eppendorf. In total, 722 aneurysms were included in this study. A postoperative mRS > 2 was best predicted by a quadratic discriminant analysis (QDA) estimator in the internal test set, with an area under the receiver operating characteristic curve (ROC-AUC) of 0.87 ± 0.03 and a sensitivity and specificity of 0.83 ± 0.08 and 0.71 ± 0.07, respectively. A Multilayer Perceptron predicted the post- to preoperative mRS difference > 1 with a ROC-AUC of 0.70 ± 0.02 and a sensitivity and specificity of 0.74 ± 0.07 and 0.50 ± 0.04, respectively. The QDA was the best model for predicting a permanent new neurological deficit with a ROC-AUC of 0.71 ± 0.04 and a sensitivity and specificity of 0.65 ± 0.24 and 0.60 ± 0.12, respectively. Furthermore, these models performed significantly better than the classic logistic regression models (p < 0.0001). The present results showed good performance in predicting functional and clinical outcomes after microsurgical therapy of UIAs in the internal data set, especially for the main outcome parameters, mRS and permanent neurological deficit. The external validation showed poor discrimination with ROC-AUC values of 0.61, 0.53 and 0.58 respectively for predicting a postoperative mRS > 2, a pre- and postoperative difference in mRS > 1 point and a GOS < 5. Therefore, generalizability of the models could not be demonstrated in the external validation. A SHapley Additive exPlanations (SHAP) analysis revealed that this is due to the most important features being distributed quite differently in the internal and external data sets. The implementation of newly available data and the merging of larger databases to form more broad-based predictive models is imperative in the future.

A randomized, single ascending dose safety, tolerability and pharmacokinetics study of NicaPlant® in aneurysmal subarachnoid hemorrhage patients undergoing clipping.

Introduction: Aneurysmal subarachnoid hemorrhage (aSAH) is associated with high morbidity and mortality. Post-hemorrhagic vasospasm with neurological deterioration is a major concern in this context. NicaPlant®, a modified release formulation of the calcium channel blocker nicardipine, has shown vasodilator efficacy preclinically and a similar formulation known as NPRI has shown anti-vasospasm activity in aSAH patients under compassionate use. Research question: The study aimed to assess pharmacokinetics and pharmacodynamics of NicaPlant® pellets to prevent vasospasm after clip ligation in aSAH. Material and methods: In this multicenter, controlled, randomized, dose escalation trial we assessed the safety and tolerability of NicaPlant®. aSAH patients treated by clipping were randomized to receive up to 13 NicaPlant® implants, similarly to the dose of NPRIs previous used, or standard of care treatment. Results: Ten patients across four dose groups were treated with NicaPlant® (3-13 implants) while four patients received standard of care. 45 non-serious and 13 serious adverse events were reported, 4 non-serious adverse events and 5 serious adverse events assessed a probable or possible causal relationship to the investigational medical product. Across the NicaPlant® groups there was 1 case of moderate vasospasm, while in the standard of care group there were 2 cases of severe vasospasm. Discussion and conclusion: The placement of NicaPlant® during clip ligation of a ruptured cerebral aneurysm raised no safety concern. The dose of 10 NicaPlant® implants was selected for further clinical studies.

Tailored Intraoperative MRI Strategies in High-Grade Glioma Surgery: A Machine Learning-Based Radiomics Model Highlights Selective Benefits.

BACKGROUND AND OBJECTIVES: In high-grade glioma (HGG) surgery, intraoperative MRI (iMRI) has traditionally been the gold standard for maximizing tumor resection and improving patient outcomes. However, recent Level 1 evidence juxtaposes the efficacy of iMRI and 5-aminolevulinic acid (5-ALA), questioning the continued justification of iMRI because of its associated costs and extended surgical duration. Nonetheless, drawing from our clinical observations, we postulated that a subset of intricate HGGs may continue to benefit from the adjunctive application of iMRI. METHODS: In a prospective study of 73 patients with HGG, 5-ALA was the primary technique for tumor delineation, complemented by iMRI to detect residual contrast-enhanced regions. Suboptimal 5-ALA efficacy was defined when (1) iMRI detected contrast-enhanced remnants despite 5-ALA's indication of a gross total resection or (2) surgeons observed residual fluorescence, contrary to iMRI findings. Radiomic features from preoperative MRIs were extracted using a U2-Net deep learning algorithm. Binary logistic regression was then used to predict compromised 5-ALA performance. RESULTS: Resections guided solely by 5-ALA achieved an average removal of 93.14% of contrast-enhancing tumors. This efficacy increased to 97% with iMRI integration, albeit not statistically significant. Notably, for tumors with suboptimal 5-ALA performance, iMRI's inclusion significantly improved resection outcomes (P-value: .00013). The developed deep learning-based model accurately pinpointed these scenarios, and when enriched with radiomic parameters, showcased high predictive accuracy, as indicated by a Nagelkerke R2 of 0.565 and a receiver operating characteristic of 0.901. CONCLUSION: Our machine learning-driven radiomics approach predicts scenarios where 5-ALA alone may be suboptimal in HGG surgery compared with its combined use with iMRI. Although 5-ALA typically yields favorable results, our analyses reveal that HGGs characterized by significant volume, complex morphology, and left-sided location compromise the effectiveness of resections relying exclusively on 5-ALA. For these intricate cases, we advocate for the continued relevance of iMRI.

Cortical and Subcortical Anatomy of the Orbitofrontal Cortex: A White Matter Microfiberdissection Study and Case Series.

BACKGROUND: The literature on white matter anatomy underlying the human orbitofrontal cortex (OFC) is scarce in spite of its relevance for glioma surgery. OBJECTIVE: To describe the anatomy of the OFC and of the underlying white matter fiber anatomy, with a particular focus on the surgical structures relevant for a safe and efficient orbitofrontal glioma resection. Based on anatomical and radiological data, the secondary objective was to describe the growth pattern of OFC gliomas. METHODS: The study was performed on 10 brain specimens prepared according to Klingler's protocol and dissected using the fiber microdissection technique modified according to U.T., under the microscope at high magnification. RESULTS: A detailed stratigraphy of the OFC was performed, from the cortex up to the frontal horn of the lateral ventricle. The interposed neural structures are described together with relevant neighboring topographic areas and nuclei. Combining anatomical and radiological data, it appears that the anatomical boundaries delimiting and guiding the macroscopical growth of OFC gliomas are as follows: the corpus callosum superiorly, the external capsule laterally, the basal forebrain and lentiform nucleus posteriorly, and the gyrus rectus medially. Thus, OFC gliomas seem to grow ventriculopetally, avoiding the laterally located neocortex. CONCLUSION: The findings in our study supplement available anatomical knowledge of the OFC, providing reliable landmarks for a precise topographical diagnosis of OFC lesions and for perioperative orientation. The relationships between deep anatomic structures and glioma formations described in this study are relevant for surgery in this highly interconnected area.

Current Strategies in the Treatment of Intracranial Large and Giant Aneurysms.

INTRODUCTION: Very large and giant aneurysms are among the most challenging cerebrovascular pathologies in neurosurgery. METHODS: The aim of this paper is to review the current literature on the management of very large and giant aneurysms and to describe representative cases illustrating possible treatment strategies. RESULTS: In view of the poor natural history, active management using multiprofessional individualized approaches is required to achieve aneurysm occlusion, relief of mass effect, and obliteration of the embolic source. Both reconstructive (clipping, coiling, stent-assisted coiling, flow diversion [FD]) and deconstructive techniques (parent artery occlusion [PAO], PAO in conjunction with bypass surgery, and strategies of flow modification) are available to achieve definitive treatment with acceptable morbidity. CONCLUSIONS: Patients harboring such lesions should be managed at high-volume cerebrovascular centers by multidisciplinary teams trained in all techniques of open and endovascular neurosurgery.

The influence of smoking in minimally invasive spinal fusion surgery.

BACKGROUND: The impact of smoking on spinal surgery has been studied extensively, but few investigations have focused on minimally invasive surgery (MIS) of the spine and the difference between complication rates in smokers and non-smokers. We evaluated whether a history of at least one pack-year preoperatively could be used to predict adverse peri- and postoperative outcomes in patients undergoing minimally invasive fusion procedures of the lumbar spine. In a prospective study, we assessed the clinical effectiveness of MIS in an unselected population of 187 patients. METHODS: We evaluated perioperative and postoperative complication rates in MIS fusion techniques of the lumbar spine in smoking and non-smoking patients. MIS fusion was performed using interbody fusion procedures and/or posterolateral fusion alone. RESULTS: Smokers were significantly younger than non-smokers. We did not encounter infection at the site of surgery or severe wound healing disorder in smokers. We registered no difference between the smoking and non-smoking groups with regard to peri- or postoperative complication rate, blood loss, or length of stay in hospital. We found a significant influence of smoking (p = 0.049) on the overall perioperative complication rate. CONCLUSION: MIS fusion techniques seem to be a suitable tool for treating degenerative spinal disorders in smokers.

Long-Term Outcomes in Ventriculoatrial Shunt Surgery in Patients with Pediatric Hydrocephalus: Retrospective Single-Center Study.

OBJECTIVE: Long-term outcomes are rarely reported for patients with pediatric hydrocephalus. Ventriculoperitoneal shunting is the surgical standard; nevertheless, in selected patients, a ventriculoatrial shunt (VAS) remains an important alternative. This study aimed to analyze the causes of VAS revisions and complications. METHODS: Pediatric patients who underwent their first shunt operation between 1982 and 1992 were included. The timing, cause, and modality of VAS revisions were retrospectively determined. RESULTS: Overall, 138 patients were treated for hydrocephalus and 61 patients received a VAS during the follow-up period. A primary VAS was the first shunt type in 42 (68.85%) patients. In 19 (31.15%) patients, conversions to second-line VAS were carried out. The rates of VAS revisions performed for dysfunction or elective lengthening of a short atrial catheter were 52.2% and 22.9%, respectively. There was no difference in the number of VAS revisions between patients with primary VASs and second-line VASs. Age at VAS and etiology of hydrocephalus had no effect on the number of revisions. Specific VAS complications were observed in 2 patients. Deep positioning of the distal catheter led to asymptomatic tricuspid regurgitation that was reversible after shortening of the atrial catheter. Another patient presented with shunt nephritis and completely recovered after the atrial catheter was replaced with a peritoneal catheter. CONCLUSIONS: VAS remains an appropriate second-line alternative in selected patients. Specific VAS complications were rarely observed and completely reversible after treatment. However, regular and specific follow-up examinations are strongly recommended to avoid cardiopulmonary or renal complications.

The impact of type 2 diabetes on the peri- and postoperative outcomes of minimally invasive fusion techniques in the lumbar spine.

BACKGROUND: The impact of diabetes on spinal surgery has been studied extensively, but very few studies have focused on minimal access spinal technologies (MAST) and complication rates in patients suffering from type 2 diabetes (T2DM). Diabetes increases the risk of wound healing disorders, complication rate and length of stay in the hospital. We focused on the peri- and postoperative complications of MAST in an unselected consecutive population of 187 patients suffering from degenerative disorders lumbar spine disorders. Since mostly older patients are affected by degenerative lumbar changes, we concentrated on T2DM. METHODS: We evaluated perioperative and postoperative complication rates associated with MAST fusion techniques in lumbar spine surgery in patients suffering from T2DM compared to patients without diabetes. Lumbar fusion was performed using interbody and posterolateral fusion. RESULTS: Eighteen female and sixteen male patients suffered from T2DM (15.65% and 22.22% respectively). No differences between patients with and without T2DM concerning surgery-related complications including infections, severe wound healing disorders or length of in-hospital stay were noted. Peri- or postoperative complication rates, as well as blood loss volumes, were evenly distributed between the two groups. CONCLUSIONS: T2DM is not a risk factor for the occurrence of complications in MAST.

Adult Outcome in Shunted Pediatric Hydrocephalus: Long-Term Functional, Social, and Neurocognitive Results.

OBJECTIVE: Very long-term outcomes are rarely reported for patients with shunted pediatric hydrocephalus. This study aimed to determine the functional, social, and neurocognitive outcomes of such patients after transition to adulthood. METHODS: Adult patients with pediatric hydrocephalus who underwent their first shunt operation between 1982 and 1992 were included. Functional, social, educational, working aspects, and verbal intelligence were evaluated. In patients with average or above average verbal intelligence, detailed neuropsychological testing was performed and memory, executive functioning, selective attention, and concentration were assessed. RESULTS: Overall, 137 patients underwent primary surgery because of pediatric hydrocephalus, 53 (38.7%) of whom died during the follow-up period. Of the 84 long-term survivors, 65 (77.4%) agreed to participate and were included for further analysis. Forty-five patients (69.2%) had completed secondary school, but only 34 (52.3%) were integrated in the open labor market. Although the verbal intelligence of 31 patients (47.7%) was within the normal range, 19 (29.2%) had a severe mental handicap. Shunt infections (P = 0.0025), epilepsy (P < 0.0001), and the number of shunt operations (P = 0.0082) were associated with reduced verbal intelligence. Most patients with average or above average verbal intelligence had deficits in detailed neuropsychological testing. In 23 patients, detailed neuropsychological testing was performed. CONCLUSIONS: The overall long-term outcome of patients with shunted pediatric hydrocephalus is poor. These results highlight the importance of lifelong routine controls to avoid later complications. Further, repeated neuropsychological examinations might be important to understand the patient's special needs to optimize professional support.

The influence of age on the peri- and postoperative clinical course in patients undergoing minimally invasive transforaminal lumbar interbody fusion techniques of the lumbar spine.

OBJECTIVE: As a result of continuously increasing life expectancy, the number of requests for surgery to treat degenerative diseases of the spine in the elderly population will increase. Since older age is associated with the occurrence of medical comorbidities, the demand for less extensive surgical approaches is growing. The aim of this study is to establish whether minimally invasive fusion techniques are a safe and adequate tool for use in elderly patients. PATIENTS AND METHODS: We analyzed 187 patients who underwent minimally invasive surgery (MIS) in the form of one- to four-level fusion procedures. In 146 patients, additional widening of the spinal canal was performed. The subjects were grouped into four age categories of approximately equal size (33-56, 56-66, 66-74 and 74-85). The effect of age on the incidence of peri- and postoperative complications was investigated and compared between the age groups. RESULTS: Older age was not associated with the occurrence of perioperative complications, which include wound healing disorders, hematomas, wound traction-blisters and cerebrospinal fluid leakage. Fourteen patients (7.49%) encountered distinct surgical technique related complications, making surgical revision necessary in eight patients (4.28%). Furthermore, increasing age didn't elevate the risk of postoperative adverse events, i.e. pulmonary embolism, ischemic heart attack or pneumonia, among others. However, older patients were found to stay in hospital longer than younger patients, especially when more than one level was fused. CONCLUSIONS: Minimally invasive surgery techniques are safe in elderly patients. The small-scale surgical approach guarantees a low incidence of infections and wound healing disorders. However, a longer hospital stay must be expected in older patients.

Surgical and Clinical Results of Minimally Invasive Spinal Fusion Surgery in an Unselected Patient Cohort of a Spinal Care Unit.

OBJECTIVES: To review the surgical results and to identify possible parameters influencing the clinical outcomes in an unselected patient collective undergoing minimally invasive lumbar interbody fusion in a spinal care unit. METHODS: A total of 229 adult patients who underwent minimally invasive lumbar spinal fusion between 2008 and 2016 were included in this retrospective analysis. Lumbar fusion was performed using transforaminal interbody fusion (TLIF) devices and posterolateral fusion. To eliminate confounding parameters, in all patients interbody fusion was indicated by lumbar degenerative pathologies, and surgery was performed using the same fusion device. Treatment efficacy was evaluated using scores describing pain (visual analogue scale [VAS]) and health impairment (EQ-5D, Oswestry Disability Index [ODI]). The influence of patient age, obesity, active smoking status, and co-morbidities on clinical outcome and perioperative complications was analyzed. RESULTS: The patient population reviewed had improved VAS (P(leg pain) ≤ 0.0001, P(back pain) ≤ 0.0001), ODI (P ≤ 0.0001), EQ-VAS (P ≤ 0.0001), and EQ-5D subscales "mobility", "self-care", "pain", and "anxiety" (P(mobility) ≤ 0.0001, P(self-care) = 0.41, P(pain) ≤ 0.0001, P(anxiety) = 0.011) postoperatively. Neither advanced patient age, nor increased body mass index (BMI), hypertension, or active smoking status had a significantly limiting influence on the success of minimally invasive spinal surgeries (MIS). Duration of surgery strongly correlated with the number of spinal levels treated and with intraoperative blood loss (r = 0.774, P ≤ 0.0001, n = 208). Weak positive correlations were found between patient age and duration of surgery (r = 0.184, P = 0.005, n = 229), intraoperative blood loss (r = 0.165, P = 0.012, n = 229), and duration of hospitalization (r = 0.270, P ≤ 0.0001, n = 228), respectively. When compared to non-smokers, smokers were younger (P ≤ 0.0001), and had a significantly lower BMI (P = 0.001), shorter durations of surgery (P ≤ 0.0001), decreased intraoperative blood loss (P = 0.022), and shorter hospital stays (P = 0.006), respectively. Complications occurred in 17 patients (7%) and were not affected by patient age, BMI, hypertension, or active smoking status. CONCLUSION: Minimally invasive spinal surgery is a safe and effective treatment option and may be superior to open surgery in subpopulations with significant co-morbidities and risk factors, such as elderly and obese patients as well as patients with an active smoking status.

Abdominal Pseudocysts and Peritoneal Catheter Revisions: Surgical Long-Term Results in Pediatric Hydrocephalus.

OBJECTIVE: An abdominal pseudocyst (APC) is a distal catheter site-specific failure in patients treated with ventriculoperitoneal shunts. Few studies with more than 10 patients have been reported. The aim of this study was to analyze causes of peritoneal catheter revisions with special emphasis on revisions because of an APC. METHODS: Pediatric patients with first shunt operation between 1982 and 1992 were included, and time, cause, and modality of peritoneal catheter revision were determined retrospectively. RESULTS: One hundred thirty-eight patients were treated for hydrocephalus, and 112 patients received a peritoneal catheter during the follow-up. An APC was diagnosed in 14 (12.5%) patients, and 28 revisions were needed for its treatment. The rate of shunt infection in patients with APC was 50%, but bacterial examination of the pseudofluid culture revealed infection in only 3 patients. Age at first surgical procedure, type of first surgical procedure, and etiology of hydrocephalus were not associated with APC diagnosis. APC recurred in 4 patients. These patients had a catheter repositioning directly into the peritoneum as first surgical treatment. No recurrences were observed in patients with shunt externalization or replacement of the peritoneal catheter. CONCLUSIONS: An APC is a major long-term complication after ventriculoperitoneal shunt treatment. Although a sterile inflammatory response cannot be excluded completely, our results favor the hypothesis of low-level shunt infection. In both cases, the surgical consequences are the same. An infected APC should be treated as a shunt infection. Uninfected patients can be treated with shunt externalization and replacement of only the peritoneal catheter.

Virtual Cerebral Aneurysm Clipping with Real-Time Haptic Force Feedback in Neurosurgical Education.

OBJECTIVE: Realistic, safe, and efficient modalities for simulation-based training are highly warranted to enhance the quality of surgical education, and they should be incorporated in resident training. The aim of this study was to develop a patient-specific virtual cerebral aneurysm-clipping simulator with haptic force feedback and real-time deformation of the aneurysm and vessels. METHODS: A prototype simulator was developed from 2012 to 2016. Evaluation of virtual clipping by blood flow simulation was integrated in this software, and the prototype was evaluated by 18 neurosurgeons. In 4 patients with different medial cerebral artery aneurysms, virtual clipping was performed after real-life surgery, and surgical results were compared regarding clip application, surgical trajectory, and blood flow. RESULTS: After head positioning and craniotomy, bimanual virtual aneurysm clipping with an original forceps was performed. Blood flow simulation demonstrated residual aneurysm filling or branch stenosis. The simulator improved anatomic understanding for 89% of neurosurgeons. Simulation of head positioning and craniotomy was considered realistic by 89% and 94% of users, respectively. Most participants agreed that this simulator should be integrated into neurosurgical education (94%). Our illustrative cases demonstrated that virtual aneurysm surgery was possible using the same trajectory as in real-life cases. Both virtual clipping and blood flow simulation were realistic in broad-based but not calcified aneurysms. Virtual clipping of a calcified aneurysm could be performed using the same surgical trajectory, but not the same clip type. CONCLUSIONS: We have successfully developed a virtual aneurysm-clipping simulator. Next, we will prospectively evaluate this device for surgical procedure planning and education.