Long-term risk of hemorrhage and mortality after treatment of high-grade intracranial dural arteriovenous fistulas.

BACKGROUND: Despite recent multi-institutional efforts, long-term data on clinical and radiological outcomes after treatment of high-grade dural arteriovenous fistulas (dAVFs) remain scarce. This study aimed to evaluate the long-term risk of hemorrhage and fistula-related mortality after treatment. METHODS: Retrospective analysis of all consecutive patients primarily diagnosed with a high-grade dAVF (Cognard grade 2b, 2a+b, 3, 4) between January 2012 and September 2022 at a large neurovascular center. Primary endpoints were intracranial hemorrhage (ICH) and all-cause mortality after treatment; secondary endpoints were angiographic occlusion, complication rate and neurological deficits. RESULTS: A total of 121 patients underwent 141 treatments (122 endovascular therapy (EVT), 5 radiotherapy, 14 surgery) of which 12 patients (10%) underwent retreatment. Follow-up was available in all patients for a median of 4.2 (IQR 2.5 to 6.6) years. Eleven patients (9%) died during the follow-up period, of which three deaths (2%) occurred after hemorrhagic presentation, one of them attributable to treatment. One death (0.8%) was due to delayed hemorrhage after partial occlusion from EVT. No other post-treatment bleedings occurred. Angiographic follow-up after multimodality treatment was available in 93% of patients after a median of 6 months; the overall occlusion rate was 90%. The overall rate of complications was 25% after EVT and 14% after surgery. The rates of new transient and permanent neurological deficits after EVT were 9% and 3%, respectively. CONCLUSIONS: The long-term rate of re-bleeding or dAVF-related mortality was low when high rates of angiographic occlusion were achieved. The risk for treatment-related complications leading to neurological sequela was low.

3D exoscopic versus microscopic superficial temporal artery to middle cerebral artery bypass surgery for moyamoya disease - a comparative series.

PURPOSE: Superficial temporal artery to middle cerebral artery (STA-MCA) direct bypass surgery is the most common surgical procedure to treat moyamoya disease (MMD). Here, we aim to compare the performance of the 3D exoscope in bypass surgery with the gold standard operative microscope. METHODS: All direct STA-MCA bypass procedures performed at a single university hospital for MMD between 2015 and 2023 were considered for inclusion. Data were retrospectively collected from patient files and surgical video material. From 2020 onwards, bypass procedures were exclusively performed using a digital three-dimensional exoscope as visualization device. Results were compared with a microsurgical bypass control group (2015-2019). The primary endpoint was defined as total duration of surgery, duration of completing the vascular anastomosis (ischemia time), bypass patency, number of stiches to perform the anastomosis, added stiches after leakage testing of the anastomosis and the Glasgow outcome scale (GOS) at last follow-up as secondary outcome parameter. RESULTS: A total of 16 consecutive moyamoya patients underwent 21 STA-MCA bypass procedures. Thereof, six patients were operated using a microscope and ten patients using an exoscope (ORBEYE® n = 1; AEOS® n = 9). Total duration of surgery was comparable between devices (microscope: 313 min. ± 116 vs. exoscope: 279 min. ± 42; p = 0.647). Ischemia time also proved similar between groups (microscope: 43 min. ± 19 vs. exoscope: 41 min. ± 7; p = 0.701). No differences were noted in bypass patency rates. The number of stiches per anastomosis was similar between visualization devices (microscope: 17 ± 4 vs. exoscope: 17 ± 2; p = 0.887). In contrast, more additional stiches were needed in microscopic anastomoses after leakage testing the bypass (p = 0.035). CONCLUSION: Taking into account the small sample size, end-to-side bypass surgery for moyamoya disease using a foot switch-operated 3D exoscope was not associated with more complications and led to comparable clinical and radiological results as microscopic bypass surgery.

Predicting outcome after aneurysmal subarachnoid hemorrhage by exploitation of signal complexity: a prospective two-center cohort study.

BACKGROUND: Signal complexity (i.e. entropy) describes the level of order within a system. Low physiological signal complexity predicts unfavorable outcome in a variety of diseases and is assumed to reflect increased rigidity of the cardio/cerebrovascular system leading to (or reflecting) autoregulation failure. Aneurysmal subarachnoid hemorrhage (aSAH) is followed by a cascade of complex systemic and cerebral sequelae. In aSAH, the value of entropy has not been established yet. METHODS: aSAH patients from 2 prospective cohorts (Zurich-derivation cohort, Aachen-validation cohort) were included. Multiscale Entropy (MSE) was estimated for arterial blood pressure, intracranial pressure, heart rate, and their derivatives, and compared to dichotomized (1-4 vs. 5-8) or ordinal outcome (GOSE-extended Glasgow Outcome Scale) at 12 months using uni- and multivariable (adjusted for age, World Federation of Neurological Surgeons grade, modified Fisher (mFisher) grade, delayed cerebral infarction), and ordinal methods (proportional odds logistic regression/sliding dichotomy). The multivariable logistic regression models were validated internally using bootstrapping and externally by assessing the calibration and discrimination. RESULTS: A total of 330 (derivation: 241, validation: 89) aSAH patients were analyzed. Decreasing MSE was associated with a higher likelihood of unfavorable outcome independent of covariates and analysis method. The multivariable adjusted logistic regression models were well calibrated and only showed a slight decrease in discrimination when assessed in the validation cohort. The ordinal analysis revealed its effect to be linear. MSE remained valid when adjusting the outcome definition against the initial severity. CONCLUSIONS: MSE metrics and thereby complexity of physiological signals are independent, internally and externally valid predictors of 12-month outcome. Incorporating high-frequency physiological data as part of clinical outcome prediction may enable precise, individualized outcome prediction. The results of this study warrant further investigation into the cause of the resulting complexity as well as its association to important and potentially preventable complications including vasospasm and delayed cerebral ischemia.

Decompressive craniectomy plus best medical treatment versus best medical treatment alone for spontaneous severe deep supratentorial intracerebral haemorrhage: a randomised controlled clinical trial.

BACKGROUND: It is unknown whether decompressive craniectomy improves clinical outcome for people with spontaneous severe deep intracerebral haemorrhage. The SWITCH trial aimed to assess whether decompressive craniectomy plus best medical treatment in these patients improves outcome at 6 months compared to best medical treatment alone. METHODS: In this multicentre, randomised, open-label, assessor-blinded trial conducted in 42 stroke centres in Austria, Belgium, Finland, France, Germany, the Netherlands, Spain, Sweden, and Switzerland, adults (18-75 years) with a severe intracerebral haemorrhage involving the basal ganglia or thalamus were randomly assigned to receive either decompressive craniectomy plus best medical treatment or best medical treatment alone. The primary outcome was a score of 5-6 on the modified Rankin Scale (mRS) at 180 days, analysed in the intention-to-treat population. This trial is registered with ClincalTrials.gov, NCT02258919, and is completed. FINDINGS: SWITCH had to be stopped early due to lack of funding. Between Oct 6, 2014, and April 4, 2023, 201 individuals were randomly assigned and 197 gave delayed informed consent (96 decompressive craniectomy plus best medical treatment, 101 best medical treatment). 63 (32%) were women and 134 (68%) men, the median age was 61 years (IQR 51-68), and the median haematoma volume 57 mL (IQR 44-74). 42 (44%) of 95 participants assigned to decompressive craniectomy plus best medical treatment and 55 (58%) assigned to best medical treatment alone had an mRS of 5-6 at 180 days (adjusted risk ratio [aRR] 0·77, 95% CI 0·59 to 1·01, adjusted risk difference [aRD] -13%, 95% CI -26 to 0, p=0·057). In the per-protocol analysis, 36 (47%) of 77 participants in the decompressive craniectomy plus best medical treatment group and 44 (60%) of 73 in the best medical treatment alone group had an mRS of 5-6 (aRR 0·76, 95% CI 0·58 to 1·00, aRD -15%, 95% CI -28 to 0). Severe adverse events occurred in 42 (41%) of 103 participants receiving decompressive craniectomy plus best medical treatment and 41 (44%) of 94 receiving best medical treatment. INTERPRETATION: SWITCH provides weak evidence that decompressive craniectomy plus best medical treatment might be superior to best medical treatment alone in people with severe deep intracerebral haemorrhage. The results do not apply to intracerebral haemorrhage in other locations, and survival is associated with severe disability in both groups. FUNDING: Swiss National Science Foundation, Swiss Heart Foundation, Inselspital Stiftung, and Boehringer Ingelheim.

Even short-term training improves the skills of novice exoscope users: a prospective laboratory experiment.

BACKGROUND: The surgical 3D exoscopes have recently been introduced as an alternative to the surgical microscopes in microneurosurgery. Since the exoscope availability is still limited, it is relevant to know whether even a short-term exoscope training develops the skills needed for performing exoscope-assisted surgeries. METHODS: Ten participants (six consultants, four residents) performed two laboratory bypass test tasks with a 3D exoscope (Aesculap Aeos®). Six training sessions (6 h) were performed in between (interval of 2-5 weeks) on artificial models. The participants were divided into two groups: test group (n = 6) trained with the exoscope and control group (n = 4) with a surgical microscope. The test task was an artificial end-to-side microsurgical anastomosis model, using 12 interrupted 9-0 sutures and recorded on video. We compared the individual as well as group performance among the test subjects based on suturing time, anastomosis quality, and manual dexterity. RESULTS: Altogether, 20 bypass tasks were performed (baseline n = 10, follow-up n = 10). The median duration decreased by 28 min and 44% in the exoscope training group. The decrease was steeper (29 min, 45%) among the participants with less than 6 years of microneurosurgery experience compared to the more experienced participants (13 min, 24%). After training, the participants with at least 1-year experience of using the exoscope did not improve their task duration. The training with the exoscope led to a greater time reduction than the training with the microscope (44% vs 17%). CONCLUSIONS: Even short-term training with the exoscope led to marked improvements in exoscope-assisted bypass suturing among novice microneurosurgeons. For the more experienced participants, a plateau in the initial learning curve was reached quickly. A much longer-term effort might be needed to witness further improvement in this user group.

Long-term treatment outcomes and natural course of low-grade intracranial dural arteriovenous fistulas.

OBJECTIVE: In contrast to high-grade dural arteriovenous fistula (dAVF), low-grade dAVF is mainly associated with tinnitus and carries a low risk of morbidity and mortality. It remains unclear whether the benefits of active interventions outweigh the associated risk of complications in low-grade dAVF. METHODS: The authors conducted a retrospective single-center study that included all consecutive patients diagnosed with an intracranial low-grade dAVF (Cognard type I and IIa) during 2012-2022 with DSA. The authors analyzed symptom relief, symptomatic angiographic cure, treatment-related complications, risk for intracerebral hemorrhage (ICH), and mortality. All patients were followed up until the end of 2022. RESULTS: A total of 81 patients were diagnosed with a low-grade dAVF. Of these, 48 patients (59%) underwent treatment (all primary endovascular treatments), and 33 patients (41%) did not undergo treatment. Nine patients (19%) underwent retreatments. Angiographic follow-up was performed after median (IQR) 7.7 (6.1-24.1) months by means of DSA (mean 15.0, median 6.4 months, range 4.5-83.4 months) or MRA (mean 29.3, median 24.7 months, range 5.9-62.1 months). Symptom control was achieved in 98% of treated patients after final treatment. On final angiographic follow-up, 73% of patients had a completely occluded dAVF. There were 2 treatment-related complications resulting in 1 transient (2%) and 1 permanent (2%) neurological complication. One patient showed recurrence and progression of a completely occluded low-grade dAVF to an asymptomatic high-grade dAVF. No cases of ICH- or dAVF-related mortality were found in either treated patients (median [IQR] follow-up 5.1 [2.0-6.8] years) or untreated patients (median [IQR] follow-up 5.7 [3.2-9.0] years). CONCLUSIONS: Treatment of low-grade dAVF provides a high rate of symptom relief with small risks for complications with neurological sequela. The risks of ICH and mortality in patients with untreated low-grade dAVF are minimal. Symptoms may not reveal high-grade recurrence, and radiological follow-up may be warranted in selected patients with treated low-grade dAVF. An optimal radiographic follow-up regimen should be developed by a future prospective multicenter registry.

Intra-arterial nimodipine for the treatment of refractory delayed cerebral ischemia after aneurysmal subarachnoid hemorrhage.

BACKGROUND: Delayed cerebral ischemia (DCI) is one of the main contributors to poor clinical outcome after aneurysmal subarachnoid hemorrhage (SAH). Endovascular spasmolysis with intra-arterial nimodipine (IAN) may resolve angiographic vasospasm, but its effect on infarct prevention and clinical outcome is still unclear. We report the effect of IAN on infarction rates and functional outcome in a consecutive series of SAH patients. METHODS: To assess the effectiveness of IAN, we collected functional outcome data of all SAH patients referred to a single tertiary center since its availability (2011-2020). IAN was primarily reserved as a last tier option for DCI refractory to induced hypertension (iHTN). Functional outcome was assessed after 12 months according to the Glasgow Outcome Scale (GOS, favorable outcome = GOS4-5). RESULTS: Out of 376 consecutive SAH patients, 186 (49.5%) developed DCI. Thereof, a total of 96 (25.5%) patients remained unresponsive to iHTN and received IAN. DCI-related infarction was observed in 44 (45.8%) of IAN-treated patients with a median infarct volume of 111.6 mL (Q1: 51.6 to Q3: 245.7). Clinical outcome was available for 84 IAN-treated patients. Of those, a total of 40 (47.6%) patients reached a favorable outcome after 1 year. Interventional complications were observed in 9 (9.4%) of the IAN-treated patients. CONCLUSION: Intra-arterial spasmolysis using nimodipine infusion was associated with low treatment specific complications. Despite presenting a subgroup of severely affected SAH patients, almost half of IAN-treated patients were able to lead an independent life after 1 year of follow-up. TRIAL REGISTRATION NUMBER: German Clinical Trial Register DRKS00030505.

Corrigendum to "Infection-related failure of autologous versus allogenic cranioplasty after decompressive hemicraniectomy - A systematic review and meta-analysis" [Brain Spine 3 (2023) 101760].

[This corrects the article DOI: 10.1016/j.bas.2023.101760.].

Infection-related failure of autologous versus allogenic cranioplasty after decompressive hemicraniectomy - A systematic review and meta-analysis.

Introduction: Cranioplasty is required after decompressive craniectomy (DC) to restore brain protection and cosmetic appearance, as well as to optimize rehabilitation potential from underlying disease. Although the procedure is straightforward, complications either caused by bone flap resorption (BFR) or graft infection (GI), contribute to relevant comorbidity and increasing health care cost. Synthetic calvarial implants (allogenic cranioplasty) are not susceptible to resorption and cumulative failure rates (BFR and GI) tend therefore to be lower in comparison with autologous bone. The aim of this review and meta-analysis is to pool existing evidence of infection-related cranioplasty failure in autologous versus allogenic cranioplasty, when bone resorption is removed from the equation. Materials and methods: A systematic literature search in PubMed, EMBASE, and ISI Web of Science medical databases was performed on three time points (2018, 2020 and 2022). All clinical studies published between January 2010 and December 2022, in which autologous and allogenic cranioplasty was performed after DC, were considered for inclusion. Studies including non-DC cranioplasty and cranioplasty in children were excluded. The cranioplasty failure rate based on GI in both autologous and allogenic groups was noted. Data were extracted by means of standardized tables and all included studies were subjected to a risk of bias (RoB) assessment using the Newcastle-Ottawa assessment tool. Results: A total of 411 articles were identified and screened. After duplicate removal, 106 full-texts were analyzed. Eventually, 14 studies fulfilled the defined inclusion criteria including one randomized controlled trial, one prospective and 12 retrospective cohort studies. All but one study were rated as of poor quality based on the RoB analysis, mainly due to lacking disclosure why which material (autologous vs. allogenic) was chosen and how GI was defined. The infection-related cranioplasty failure rate was 6.9% (125/1808) for autologous and 8.3% (63/761) for allogenic implants resulting in an OR 0.81, 95% CI 0.58 to 1.13 (Z â€‹= â€‹1.24; p â€‹= â€‹0.22). Conclusion: In respect to infection-related cranioplasty failure, autologous cranioplasty after decompressive craniectomy does not underperform compared to synthetic implants. This result must be interpreted in light of limitations of existing studies. Risk of graft infection does not seem a valid argument to prefer one implant material over the other. Offering an economically superior, biocompatible and perfect fitting cranioplasty implant, autologous cranioplasty can still have a role as the first option in patients with low risk of developing osteolysis or for whom BFR might not be of major concern. Trial registration: This systematic review was registered in the international prospective register of systematic reviews. PROSPERO: CRD42018081720.

The oxygen reactivity index indicates disturbed local perfusion regulation after aneurysmal subarachnoid hemorrhage: an observational cohort study.

BACKGROUND: Cerebral autoregulation (CA) can be impaired in patients with delayed cerebral ischemia (DCI) after aneurysmal subarachnoid hemorrhage (aSAH). The Pressure Reactivity Index (PRx, correlation of blood pressure and intracranial pressure) and Oxygen Reactivity Index (ORx, correlation of cerebral perfusion pressure and brain tissue oxygenation, PbtO2) are both believed to estimate CA. We hypothesized that CA could be poorer in hypoperfused territories during DCI and that ORx and PRx may not be equally effective in detecting such local variances. METHODS: ORx and PRx were compared daily in 76 patients with aSAH with or without DCI until the time of DCI diagnosis. The ICP/PbtO2-probes of DCI patients were retrospectively stratified by being in or outside areas of hypoperfusion via CT perfusion image, resulting in three groups: DCI + /probe + (DCI patients, probe located inside the hypoperfused area), DCI + /probe- (probe outside the hypoperfused area), DCI- (no DCI). RESULTS: PRx and ORx were not correlated (r = - 0.01, p = 0.56). Mean ORx but not PRx was highest when the probe was located in a hypoperfused area (ORx DCI + /probe + 0.28 ± 0.13 vs. DCI + /probe- 0.18 ± 0.15, p < 0.05; PRx DCI + /probe + 0.12 ± 0.17 vs. DCI + /probe- 0.06 ± 0.20, p = 0.35). PRx detected poorer autoregulation during the early phase with relatively higher ICP (days 1-3 after hemorrhage) but did not differentiate the three groups on the following days when ICP was lower on average. ORx was higher in the DCI + /probe + group than in the other two groups from day 3 onward. ORx and PRx did not differ between patients with DCI, whose probe was located elsewhere, and patients without DCI (ORx DCI + /probe- 0.18 ± 0.15 vs. DCI- 0.20 ± 0.14; p = 0.50; PRx DCI + /probe- 0.06 ± 0.20 vs. DCI- 0.08 ± 0.17, p = 0.35). CONCLUSIONS: PRx and ORx are not interchangeable measures of autoregulation, as they likely measure different homeostatic mechanisms. PRx represents the classical cerebrovascular reactivity and might be better suited to detect disturbed autoregulation during phases with moderately elevated ICP. Autoregulation may be poorer in territories affected by DCI. These local perfusion disturbances leading up to DCI may be more readily detected by ORx than PRx. Further research should investigate their robustness to detect DCI and to serve as a basis for autoregulation-targeted treatment after aSAH.

How I do it: surgery for spinal arteriovenous malformations.

BACKGROUND: Spinal arteriovenous malformations (AVM) are rare lesions. They may present with intramedullary hemorrhage or edema, often inducing severe neurological deficits. Active treatment of spinal AVMs is challenging even for experienced neurosurgeons. METHOD: Anticipation of anatomy and AVM angiocharacteristics from preoperative imaging is key for successful treatment. Information gathered from MRI and DSA has to be then matched to intraoperative findings. This is a prerequisite for reasonably safe and structured lesion removal. CONCLUSION: We provide a structured approach for surgical treatment of spinal AVMs, supplemented by high-resolution video and imaging material.

Subtemporal approach for cavernous sinus meningiomas - Simple and effective.

Background: Over the past few decades, there has been a paradigm shift in treatment strategy for cavernous sinus meningiomas (CSMs). Preserving neurological function and cranial nerve (CN) decompression have become the primary goal of cases eligible for surgical treatment. Extensive skull base dissection and drilling can be avoided by approaching these lesions through a subtemporal route. Methods: We describe the subtemporal approach in a step-by-step fashion illustrating its advantages and pitfalls through and illustrative case. Results: The subtemporal approach to CSMs is a valuable alternative for CN decompression and maximal safe resection. We describe the technique in comparison to classical skull base approaches. Although rare, recurrence after adjuvant maximal radiation is possible leaving reoperation as the only treatment option. Conclusion: The subtemporal approach offers a less invasive alternative for initial and redo CN decompression and successful symptom control in patients suffering from CSM.

Small amount of alcohol did not deteriorate microsurgical dexterity: a prospective laboratory study.

BACKGROUND: Alcohol consumption has been reported to deteriorate surgical performance both immediately after consumption as well as on the next day. We studied the early effects of alcohol consumption on microsurgical manual dexterity in a laboratory setting. METHOD: Six neurosurgeons or neurosurgical residents (all male) performed micro- and macro suturing tasks after consuming variable amounts of alcohol. Each participant drank 0-4 doses of alcohol (14 g ethanol). After a delay of 60-157 min, he performed a macrosurgical and microsurgical task (with a surgical microscope). The tasks consisted of cutting and re-attaching a circular latex flap (diameter: 50 mm macrosuturing, 4 mm microsuturing) with eight interrupted sutures (4-0 multifilament macrosutures, 9-0 monofilament microsutures). We measured the time required to complete the sutures, and the amplitude and the frequency of physiological tremor during the suturing. In addition, we used a four-point ordinal scale to rank the quality of the sutures for each task. Each participant repeated the tasks several times on separate days varying the pre-task alcohol consumption (including one sober task at the end of the data collection). RESULTS: A total of 93 surgical tasks (47 macrosurgical, 46 microsurgical) were performed. The fastest microsurgical suturing (median 11 min 49 s, [interquartile range (IQR) 654 to 761 s]) was recorded after three doses of alcohol (median blood alcohol level 0.32‰). The slowest microsurgical suturing (median 15 min 19 s, [IQR 666 to 1121 s]) was observed after one dose (median blood alcohol level 0‰). The quality of sutures was the worst (mean 0.70 [standard deviation (SD) 0.48] quality points lost) after three doses of alcohol and the best (mean 0.33 [SD 0.52] quality points lost) after four doses (median blood alcohol level 0.44‰). CONCLUSIONS: Consuming small amount of alcohol did not deteriorate microsurgical performance in our study. An observed reduction in physiological tremor may partially explain this.

Aneurysmal Subarachnoid Hemorrhage in Hospitalized Patients on Anticoagulants-A Two Center Matched Case-Control Study.

Objective-Direct oral anticoagulants (DOAC) are replacing vitamin K antagonists (VKA) for the prevention of ischemic stroke and venous thromboembolism. We set out to assess the effect of prior treatment with DOAC and VKA in patients with aneurysmal subarachnoid hemorrhage (SAH). Methods-Consecutive SAH patients treated at two (Aachen, Germany and Helsinki, Finland) university hospitals were considered for inclusion. To assess the association between anticoagulant treatments on SAH severity measure by modified Fisher grading (mFisher) and outcome as measured by the Glasgow outcome scale (GOS, 6 months), DOAC- and VKA-treated patients were compared against age- and sex-matched SAH controls without anticoagulants. Results-During the inclusion timeframes, 964 SAH patients were treated in both centers. At the time point of aneurysm rupture, nine patients (0.93%) were on DOAC treatment, and 15 (1.6%) patients were on VKA. These were matched to 34 and 55 SAH age- and sex-matched controls, re-spectively. Overall, 55.6% of DOAC-treated patients suffered poor-grade (WFNS4-5) SAH compared to 38.2% among their respective controls (p = 0.35); 53.3% of patients on VKA suffered poor-grade SAH compared to 36.4% in their respective controls (p = 0.23). Neither treatment with DOAC (aOR 2.70, 95%CI 0.30 to 24.23; p = 0.38), nor VKA (aOR 2.78, 95%CI 0.63 to 12.23; p = 0.18) were inde-pendently associated with unfavorable outcome (GOS1-3) after 12 months. Conclusions-Iatrogenic coagulopathy caused by DOAC or VKA was not associated with more severe radiological or clinical subarachnoid hemorrhage or worse clinical outcome in hospitalized SAH patients.

Three-Dimensional Exoscopic Versus Microscopic Resection of Vestibular Schwannomas: A Comparative Series.

BACKGROUND: Microsurgical resection of vestibular schwannoma (VS) is highly challenging, especially because surgical treatment nowadays is mainly reserved for larger (Koos grade 3 and 4) tumors. OBJECTIVE: To assess the performance of three-dimensional exoscope use in VS resection in comparison with the operative microscope. METHODS: Duration of surgery and clinical and radiological results were collected for 13 consecutive exoscopic schwannoma surgeries. Results were compared with 26 preceding microsurgical resections after acknowledging similar surgical complexity between groups by assessment of tumor size (maximum diameter and Koos grade), the presence of meatal extension or cystic components, and preoperative hearing and facial nerve function. RESULTS: Total duration of surgery was comparable between microscopically and exoscopically operated patients (264 minutes ± 92 vs 231 minutes ± 84, respectively; P = .276). However, operative time gradually decreased in consecutive exoscopic cases and in a multiple regression model predicting duration of surgery, and exoscope use was associated with a reduction of 58.5 minutes (95% CI -106.3 to -10.6; P = .018). Tumor size was identified as the main determinant of duration of surgery (regression coefficient = 5.50, 95% CI 3.20-7.80) along meatal extension and the presence of cystic components. No differences in postoperative hearing preservation and facial nerve function were noted between the exoscope and the microscope. CONCLUSION: Resection of VS using a foot switch-operated three-dimensional exoscope is safe and leads to comparable clinical and radiological results as resection with the operative microscope.

Ocular Trauma with Ophthalmic Artery Injury as a Rare Cause of Subarachnoid Hemorrhage: a Case Report and Review of the Literature.

BACKGROUND AND IMPORTANCE: Traumatic avulsion of the ophthalmic artery is a rare cause of subarachnoid hemorrhage (SAH). In this case, a relative minor fall with isolated ocular trauma caused bulbar dislocation and rupture of the ophthalmic artery in its intracranial segment resulting in subarachnoid bleeding. CLINICAL PRESENTATION: In a female patient in her 70s, a direct penetrating trauma to the orbit by a door handle resulted in basal SAH with blood dispersion into both Sylvian fissures. Cerebral angiography revealed a blunt-ending stump at the origin of the ophthalmic artery. To provide protection against further bleeding, a flow diverter stent was placed in the internal carotid artery to cover the origin of the ophthalmic artery. After a longer intensive care stay complicated by pneumonia and respiratory insufficiency, the patient made a full recovery. Of all four reported cases (including ours), delayed cerebral ischemia was seen in one patient and hydrocephalus in two patients. These potential complications necessitate close observation and fitting treatment similar to aneurysmal SAH. CONCLUSION: Due to similar physiologic aspects, this type of bleed mimics many aspects of aneurysmal SAH. In this case, we observed no hydrocephalus or the development of delayed cerebral ischemia. This represents, however, the first reported case treated by placement of a flow diverter stent to prevent rebleeding and pseudoaneurysm formation.

How I do it-Helsinki style mini-pterional craniotomy for clipping of middle cerebral artery bifurcation aneurysms.

BACKGROUND: Different versions of the mini-pterional (MPT) approach have been described often with the idea the smaller the better. Attempts to reduce incision and craniotomy size for better cosmetic results should not be performed at the expense of safety. METHOD: We present our take on the MPT as a balance between size and safety which can be adopted by vascular neurosurgeons in training. The craniotomy stays within the confines of the superior temporal line and is completely covered by temporal muscle after closure. CONCLUSION: This approach is cosmetically superior while still offering anatomical familiarity and sufficient instrument maneuverability.

How I do it: lateral approach for craniocervical junction tumors.

BACKGROUND: The far lateral approach has been developed to access lesions at the craniocervical junction and upper cervical spinal canal. Associated morbidity triggered the development of less invasive tailored approaches. METHOD: In this lateral approach to the craniocervical junction, the occipital condyle is kept intact, vertebral artery manipulation is minimized, and the sigmoid sinus is not skeletonized. A linear incision through skin and muscles and use of an abdominal wall fat graft minimize the risk of cerebrospinal fluid leakage. CONCLUSIONS: The exposure provided is sufficient for the majority of tumors in this region and allows for low complication rates.