Search

In neuroendoscopy, an assistant surgeon holds the endoscope while the operating surgeon performs brain surgery using surgical instruments in both hands. The assistant surgeon’s task can be strenuous over time, especially in long surgeries, and unsteadiness or tremor might affect the visualization quality that the operating surgeon depends upon. Existing mechanical and pneumatic arms offer limited flexibility. We propose a robotic assistant as a third hand to the surgeon. It holds the endoscope and can be moved freely or held in place. As a proof of concept, we attached a neuroendoscope to an offthe- shelf robot with a custom handle, including a force/torque (F/T) sensor. We qualitatively identified the requirements for the third hand with a surgeon as a participant. We also quantitatively identified the range of forces applied by the endoscope to act as a retractor on two brain phantoms while visualizing the surgical site. With our proof of concept study, we could show the feasibility of robotic assistance in neuroendoscopy. Based on our observations, we found that an intuitive input device to switch the different robot modes, a second F/T sensor to measure the surgeon’s input and tissue interaction separately, and a differently shaped precision grip handle represent promising improvements to our third hand prototype.

Objective: Mastery of the posterior clinoidectomy technique is of utmost importance for neurosurgeons who specialize in endoscopic endonasal approaches, because the posterior clinoid process (PCP) is commonly involved in chondroid tumor resection. Three main techniques for posterior clinoidectomy have been developed: intradural, extradural, and transcavernous interdural. The authors introduce here a novel technical variant in which the transcavernous approach is extended to the dorsal clinoidal space after transection of the caroticoclinoid ligament, and they elaborate on its clinical application on the basis of anatomical dissections and radiological studies., Methods: The authors reviewed CT angiography images and 3D reconstruction of the PCP in 50 adults to analyze the height and presence of ossified ligament attachments. In addition, endoscopic endonasal posterior clinoidectomy was performed in 20 lightly embalmed postmortem human heads. Three techniques, including extradural, transcavernous, and extended transcavernous posterior clinoidectomy, were performed sequentially, and anatomical landmarks and areas exposed with each technique were investigated and compared., Results: Using radiological studies, the authors categorized the PCPs as 1 of 2 types: 1) normal, defined as less than or equal to 8 mm high with no ossified ligament attachments; or 2) complex, defined as greater than 8 mm high with or without an ossified ligament attachment. Compared with extradural (exposed PCP height 4.7 ± 0.5 mm) and transcavernous (exposed PCP height 7.3 ± 0.8 mm) posterior clinoidectomies, the extended transcavernous posterior clinoidectomy provided the maximally exposed PCP height (9.6 ± 0.4 mm; p < 0.0001)., Conclusions: This report details the extended transcavernous posterior clinoidectomy as a novel technical variant for achieving maximal exposure of the PCP in endoscopic endonasal surgery. In addition, the positive results establish the importance of preoperative skull base imaging for surgical planning.

Background/objectives: Detailed morphometric analysis of an aneurysm and the related vascular bifurcation are critical factors when determining rupture risk and planning treatment for unruptured intracranial aneurysms (UIAs). The standard visualization of digital subtraction angiography (DSA) and its 3D reconstruction on a 2D monitor provide precise measurements but are subject to variability based on the rater. Visualization using virtual (VR) and augmented reality platforms can overcome those limitations. It is, however, unclear whether accurate measurements of the aneurysm and adjacent arterial branches can be obtained on VR models. This study aimed to assess interrater reliability and compare measurements between 3D VR, standard 2D DSA, and 3D DSA reconstructions, evaluating the reliability and accuracy of 3D VR as a measurement tool., Methods: A pool of five neurosurgeons performed three individual analyses on each of the ten UIA cases, measuring them in completely immersed 3D VR and the standard on-screen format (2D DSA and 3D reconstruction). This resulted in three independent measurements per modality for each case. Interrater reliability of measurements and morphology characterization, comparative differences, measurement duration, and VR user experience were assessed., Results: Interrater reliability for 3D VR measurements was significantly higher than for 3D DSA measurements (3D VR mean intraclass correlation coefficient [ICC]: 0.69 ± 0.22 vs. 3D DSA mean ICC: 0.36 ± 0.37, p = 0.042). No significant difference was observed between 3D VR and 2D DSA (3D VR mean ICC: 0.69 ± 0.22 vs. 2D DSA mean ICC: 0.43 ± 0.31, p = 0.12). A linear mixed-effects model showed no effect of 3D VR and 3D DSA (95% CI = -0.26-0.28, p = 0.96) or 3D VR and 2D DSA (95% CI = -0.02-0.53, p = 0.066) on absolute measurements of the aneurysm in the anteroposterior, mediolateral, and craniocaudal dimensions., Conclusions: 3D VR technology allows for reproducible, accurate, and reliable measurements comparable to measurements performed on a 2D screen. It may also potentially improve precision for measurements of non-planar aneurysm dimensions.

Objective: Recurrent cerebrospinal fluid (CSF) rhinorrhea caused by sequential, anatomically separated skull base defects is rarely reported in the literature. Neither management nor etiology has been sufficiently investigated. We present an illustrative case and a systematic review of the literature regarding etiology, diagnostics, and management of this rare phenomenon., Methods: A systematic literature search looking for articles reporting sequential CSF leaks with multiple skull base defects was performed. Data from included articles were descriptively reported, and the quality of the included studies was assessed with Grading of Recommendations Assessment, Development and Evaluation., Results: A 71-year-old woman with posttraumatic CSF rhinorrhea and left-sided CSF otorrhea due to a left-sided horizontal fracture of the petrous bone presented at our institution. After initial surgical repair and a 10-week symptom-free interval, CSF rhinorrhea recurred. Imaging revealed a preexisting contralateral meningoencephalocele of the lateral sphenoid recess causing recurrent CSF rhinorrhea most likely after initial traumatic laceration. The defect was successfully treated. A literature search identified 366 reports, 6 of which were included in the systematic review with a total of 10 cases. Quality was deemed good in 8 of 10 cases. The most common location for primary and sequential CSF leaks was along the sphenoid bone (4/10 and 5/10 patients, respectively). All publications except one reported the presence of a meningo (encephalo)cele as cause of the sequential CSF leak., Conclusions: Occurrence of recurrent CSF rhinorrhea due to an anatomically separated sequential skull base lesion remains a rare phenomenon. Reassessment of imaging studies and a structured diagnostic workup to detect sequential CSF leaks independent of the primary lesion should is recommended., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Thyroid-stimulating hormone-secreting adenomas (TSH-oma) are exceptionally rare.1 The primary treatment is surgical resection with radiation and pharmacotherapy postoperatively if subtotal resection, especially with cavernous sinus invasion.2 We present the case of a 29-year-old man with TSH-oma with cavernous sinus medial wall invasion. This is the first documented case with selective resection of the cavernous sinus medial wall to achieve a complete resection and biochemical remission in TSH-oma through endoscopic endonasal approach. The patient had elevated TSH and thyroid hormones with symptoms of weight loss, palpitations, excess sweating, and decreased endurance. MRI revealed a 1.3 × 2.1 × 1.2 cm contrast-enhancing sellar mass with rightward pituitary gland displacement without evidence of cavernous sinus invasion (Knosp 2). The patient consented to procedure/publication. No institutional review board approval needed per institution. We performed standard resection of the firm sellar tumor portion and noted that there was tumor invasion into the left cavernous sinus medial wall dura. The bony opening was expanded to expose the anterior wall of the cavernous sinus, which was opened to identify the cavernous internal carotid artery and the medial wall attachments. The thickened medial wall was completely resected. We achieved a complete tumor resection, and the patient's TSH and thyroid hormone dropped to a desired threshold.3 Tumor stained for GATA3 and PIT1, characterizing the TSH-oma.4,5 Understanding cavernous sinus vascular and ligamentous anatomy allows for safe separation of invaded medial wall dura from the cavernous internal carotid artery,6 allowing for a more complete tumor resection, improving surgical cure rates, and sparing the patient from future radiation and pharmacotherapy., (Copyright © Congress of Neurological Surgeons 2024. All rights reserved.)

Objective: The mainstay of treatment for skull base chordoma (SBC) is maximal safe resection followed by radiotherapy. However, even after gross-total resection (GTR), the recurrence rate is high due to microscopic disease in the resection margins. Therefore, supramarginal resection (SMR) could be beneficial, as has been shown for sacral chordoma. The paradigm of postoperative radiation therapy for every patient has also begun to change, as molecular profiling has shown variability in the risk of recurrence. The aim of this study was to present the concept of SMR applied to SBC, along with an individualized decision for postoperative radiation therapy., Methods: This is a retrospective analysis of all SBCs operated on by the senior author between 2018 and 2023. SMR was defined as negative histological margins of bone and/or dura mater, along with evidence of bone resection beyond the tumor margins in the craniocaudal and lateral planes on postoperative imaging. Tumors were classified into 3 molecular recurrence risk groups (group A, low risk; group B, intermediate risk; and group C, high risk). Postoperative radiation therapy was indicated in group C tumors, in group B chordomas without SMR, or in cases of patient preference., Results: Twenty-two cases of SBC fulfilled the inclusion criteria. SMR was achieved in 12 (55%) cases, with a mean (range) amount of bone resection beyond the tumor margins of 10 (2-20) mm (+40%) in the craniocaudal axis and 6 (1-15) mm (+31%) in the lateral plane. GTR and near-total resection were each achieved in 5 (23%) cases. Three (19%) tumors were classified as group A, 12 (75%) as group B, and 1 (6%) as group C. Although nonsignificant due to the small sample size, the trends showed that patients in the SMR group had smaller tumor volumes (13.9 vs 19.6 cm3, p = 0.35), fewer previous treatments (33% vs 60% of patients, p = 0.39), and less use of postoperative radiotherapy (25% vs 60%, p = 0.19) compared to patients in the non-SMR group. There were no significant differences in postoperative CSF leak (0% vs 10%, p = 0.45), persistent cranial nerve palsy (8% vs 20%, p = 0.57), and tumor recurrence (8% vs 10%, p = 0.99; mean follow-up 15 months) rates between the SMR and non-SMR groups., Conclusions: In select cases, SMR of SBC appears to be feasible and safe. Larger cohorts and longer follow-up evaluations are necessary to explore the benefit of SMR and individualized postoperative radiation therapy on progression-free survival.

Background:  The literature concerning the management of antiplatelet (AP) and anticoagulation (AC) medication in the perioperative phase of craniotomy remains scarce. The aim of this international survey was to investigate the current practice among neurosurgeons regarding their perioperative management of AP and AC medication., Methods:  We distributed an online survey to neurosurgeons worldwide with questions concerning their perioperative practice with AP and AC medication in patients undergoing craniotomy. Descriptive statistics were performed., Results:  A total of 130 replies were registered. The majority of responders practice neurosurgery in Europe (79%) or high-income countries (79%). Responders reported in 58.9 and 48.8% to have institutional guidelines for the perioperative management of AP and AC medication. Preoperative interruption time was reported heterogeneously for the different types of AP and AC medication with 40.4% of responders interrupting aspirin (ASA) for 4 to 6 days and 45.7% interrupting clopidogrel for 6 to 8 days. Around half of the responders considered ASA safe to be continued or resumed within 3 days for bypass (55%) or vascular (49%) surgery, but only few for skull base or other tumor craniotomies in general (14 and 26%, respectively). Three quarters of the responders (74%) did not consider AC safe to be continued or resumed early (within 3 days) for any kind of craniotomy. ASA was considered to have the lowest risk of bleeding. Nearly all responders (93%) agreed that more evidence is needed concerning AP and AC management in neurosurgery., Conclusion:  Worldwide, the perioperative management of AP and AC medication is very heterogeneous among neurosurgeons., Competing Interests: None declared., (Thieme. All rights reserved.)

Objective: Tumors located in the retrochiasmatic region with extension to the third ventricle might be difficult to access when the pituitary-chiasmatic corridor is narrow. Similarly, tumor extension into the interpeduncular and retrosellar space poses a major surgical challenge. Pituitary transposition techniques have been developed to gain additional access. However, when preoperative pituitary function is already impaired or the risk of postoperative panhypopituitarism (PH) is considered to be particularly high, removal of the pituitary gland (PG) might be the preferred option to increase the working corridor. The aim of this study was to describe the relevant surgical anatomy, operative steps, and clinical experience with the endoscopic endonasal pituitary sacrifice (EEPS) and transsellar approach., Methods: This study comprised anatomical dissections to highlight the relevant surgical steps and a retrospective case series reporting clinical characteristics, indications, and outcomes of patients who underwent EEPS. The surgical technique is as follows: both lateral opticocarotid recesses are exposed laterally, the limbus sphenoidale superiorly, and the sellar floor inferiorly. After opening the dura, the PG is detached circumferentially and mobilized off the medial walls of the cavernous sinuses. The descending branches of the superior hypophyseal artery are coagulated, and the stalk is transected. After removal of the PG, drilling of the dorsum sellae and bilateral posterior clinoidectomies are performed to gain access to the hypothalamic region, interpeduncular, and prepontine cisterns., Results: From 2018 to 2023, 11 patients underwent EEPS. The cohort comprised mostly tuberoinfundibular craniopharyngiomas (n = 8, 73%). Seven (64%) patients had partial or complete anterior PG dysfunction preoperatively, while 4 (36%) had preoperative diabetes insipidus. Because of the specific tumor configuration, the chance of preserving endocrine function was estimated to be very low in patients with intact function. The main reasons for pituitary sacrifice were impaired visibility and surgical accessibility to the retrochiasmatic and retrosellar spaces. Gross-total tumor resection was achieved in 10 (91%) patients and near-total resection in 1 (9%) patient. Two (18%) patients experienced a postoperative CSF leak, requiring surgical revision., Conclusions: When preoperative pituitary function is already impaired or the risk for postoperative PH is considered particularly high, the EEPS and transsellar approach appears to be a feasible surgical option to improve visibility and accessibility to the retrochiasmatic hypothalamic and retrosellar spaces, thus increasing tumor resectability.

Background: H3 K27-altered diffuse midline gliomas (DMGs) are rare tumors, which are, regardless of their histological appearance, classified as World Health Organization grade 4 tumors. They are characterized by a diffuse growth pattern, midline anatomical location, and poor prognosis. Although DMGs occur predominantly in childhood, these tumors can also be found in young adults., Observations: The authors present a case of a 29-year-old patient who was found unconscious with a Glasgow Coma Scale score of 4, along with abnormal extensor movements and bilateral middilated nonreactive pupils. Computed tomography revealed obstructive hydrocephalus due to an acute hemorrhage in a right thalamic lesion. To drain the hydrocephalus and relieve the ongoing central herniation, emergent placement of a right-sided, and later a left-sided, extraventricular drain was performed. Despite the postoperative resolution of hydrocephalus, the patient died shortly after because of the central brain herniation that had occurred. Brain autopsy revealed a H3 K27-altered DMG in the right thalamus., Lessons: Although typically described in the pediatric population and located in the pons, H3 K27-altered DMG should also be considered in young adult patients with midline lesions, particularly if they are located in the thalamus or brainstem. In rare cases, H3 K27-altered DMG may present with an acute tumor-related hemorrhage, leading to a fulminant clinical course.

Objective: The modern management of patients with Koos grade IV vestibular schwannomas (VSs) aims at functional preservation and long-term tumor control. Gross-total resection (GTR) leads to optimal tumor control but frequently also results in permanent facial nerve (FN) palsy. Subtotal resection (STR) or near-total resection (NTR) followed by a wait-and-scan protocol and second-line radiation therapy (RT) in case of progressive residuals yields excellent tumor control rates with less permanent morbidity., Methods: The authors present the results of their prospective cohort of Koos grade IV VS patients who underwent less-than-total resection followed by a wait-and-scan protocol between January 2009 and December 2019 and discuss the latest evidence on this controversial subject. The cohort was followed up with annual clinical and volumetric outcome analyses after standardized MRI., Results: Forty-eight patients were included in the analysis. The mean extent of resection was 87% (median 91%, range 45%-100%), best fitting into the definition of STR rather than NTR. In 2 cases, the proximal portion of the FN at the brainstem could not be reliably identified and monitored during the initial operation, and a second-stage resection was necessary. At 4.4 years after surgery, 81% (39/48) of the tumor residuals regressed or were stable in size. The percentage of regressive tumor residuals increased over time. Nineteen percent (9/48) of the tumor residuals displayed volumetric progression within a mean time of 35 months (median 36 months, range 14-72 months), resulting in a Kaplan-Meier estimate for progression-free survival of 79% after 4 years; higher postoperative volume showed a linear correlation with higher volumetric progression (factor 1.96, 95% CI 1.67-2.30; p < 0.001). Thirty-four of the 48 (71%) patients continue to undergo a wait-and-scan protocol. Second-line RT was performed in 14 patients (29%) within a mean time of 25 months (median 23 months, range 5-54 months), 12 (86%) of whom responded with post-RT pseudoprogression, resulting in an overall tumor control rate of 96%. At the 4.4-year follow-up from the initial resection, 92% of the patients had a good facial outcome (House-Brackmann [HB] grade I or II), 6% had a fair facial outcome (HB grade III), and 2% had a poor facial outcome (HB grades IV-VI). So far, there has been no need for salvage surgery after RT., Conclusions: STR followed by observation and second-line RT in cases of progression leads to good facial outcome and an excellent tumor control rate in the longer term.

Objective: Discontinuation of antithrombotics (AT) prior to elective cranial procedures is common practice, despite the higher risk of thromboembolic complications in these patients. The aim of this study was to investigate the risks and benefits of a new perioperative management protocol of continuation or ultra-early AT resumption in elective cranial procedures., Methods: This study was an analysis of a prospectively collected cohort of patients undergoing elective cranial surgery with (AT group) and without (control group) AT. For extraaxial or shunt surgeries, acetylsalicylic acid (ASA) was continued perioperatively. For intraaxial pathologies, ASA was discontinued 2 days before surgery and resumed on postoperative day 3. All other AT were discontinued according to their pharmacokinetics, and resumed on postoperative day 3 after unremarkable postoperative imaging. Additionally, the authors performed a retrospective analysis of patients with AT who underwent surgery before implementation of this new AT management protocol (historical AT group). Primary and secondary outcomes were the incidence of hemorrhagic and thromboembolic complications within 3 months after surgery., Results: Outcomes of 312 patients were analyzed (83 [27%] in the AT group, 106 [34%] in the control group, and 123 [39%] in the historical AT group). For all 3 patient groups, the most common type of surgery was craniotomy for intraaxial tumors (14 [17%] in the AT group, 28 [26%] in the control group, and 60 [49%] in the historical AT group). The most commonly used AT were ASA (38 [46%] in the AT group and 78 [63%] in the historical AT group), followed by non-vitamin K oral anticoagulants (32 [39%] in the AT group and 18 [15%] in the historical AT group). The total perioperative discontinuation time in the AT group was significantly shorter than in the historical AT group (median of 4 vs 16 days; p < 0.001). The rate of hemorrhagic complications was 4% (95% CI 1-10) (n = 3/83) in the AT group, 6% (95% CI 2-12) (n = 6/106) in the control group, and 7% (95% CI 3-13) (n = 9/123) in the historical AT group (p = 0.5). The rate of thromboembolic complications was 5% (95% CI 1-12) (n = 4/82) in the AT group, 8% (95% CI 3-15) (n = 8/104) in the control group, and 7% (95% CI 3-13) (n = 8/120) in the historical AT group (p = 0.7)., Conclusions: The presented perioperative management protocol of continuation or ultra-early resumption of AT in elective cranial procedures does not seem to increase the hemorrhagic risk. Moreover, it appears to potentially protect patients from thromboembolic complications.

Background: Cerebellar contusion, swelling and herniation is frequently encoutered upon durotomy in patients undergoing retrosigmoid craniotomy for cerebellopontine angle (CPA) tumors, despite using standard methods to obtain adequate cerebellar relaxation., Objective: The aim of this study is to report an alternative cerebrospinal fluid (CSF)-diversion method using image-guided ipsilateral trigonal ventriculostomy., Methods: Single-center retro- and prospective cohort study of n  = 62 patients undergoing above-mentioned technique. Prior durotomy, CSF-diversion was performed to the point where the posterior fossa dura was visibly pulsatile. Outcome assessment consisted of the surgeon's intra- and postoperative clinical observations, and postoperative radiological imaging., Results: Fifty-two out of n  = 62 (84%) cases were eligible for analysis. The surgeons consistently reported successful ventricular puncture and a pulsatile dura prior durotomy without cerebellar contusion, swelling or herniation through the dural incision in n  = 51/52 (98%) cases. Forty-nine out of n  = 52 (94%) catheters were placed correctly within the first attempt, with the majority of catheter tips ( n  = 50, 96%) located intraventricularly (grade 1 or 2). In n  = 4/52 (8%) patients, postoperative imaging revealed evidence of a ventriculostomy-related hemorrhage (VRH) associated with an intracerebral hemorrhage [ n  = 2/52 (4%)] or an isolated intraventricular hemorrhage [ n  = 2/52 (4%)]. However, these hemorrhagic complications were not associated with neurological symptoms, surgical interventions or postoperative hydrocephalus. None of the evaluated patients demonstrated radiological signs of upward transtentorial herniation., Conclusion: The method described above efficiently allows CSF-diversion prior durotomy to reduce cerebellar pressure during retrosigmoid approach for CPA tumors. However, there is an inherent risk of subclinical supratentorial hemorrhagic complications., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (© 2023 Roethlisberger, Eberhard, Rychen, Al-Zahid, Jayapalan, Zweifel, Karuppiah and Waran.)

Background: The etiologies of parkinsonism are diverse. A possible and rare cause of hemiparkinsonism is mechanical compression of the basal ganglia and its connecting white matter tracts. The authors present a case of hemiparkinsonism caused by a lateral sphenoid wing meningioma, discuss the underlying pathophysiology based on tractography, and systematically review the existing literature., Observations: A 59-year-old female was referred for a left-sided tremor of the hand, accompanied by a cogwheel rigidity of the left arm. Symptomatology appeared 1 year earlier and worsened in the previous 6 months, finally also showing involvement of the left leg. Magnetic resonance imaging (MRI) showed a space-occupying suspected meningioma originating from the right lateral sphenoid wing and compressing the ipsilateral striatum. Tractography studies contributed to elucidate the underlying pathophysiology. Resection of the meningioma could be performed without complications. At the 4-month follow-up, the patient's hemiparkinsonism had completely recovered., Lessons: An intracranial space-occupying lesion may be a rare cause of hemiparkinsonism. In new-onset parkinsonism, especially if a secondary form is suspected, brain MRI should be performed promptly to avoid misdiagnosis and treatment. Tractography studies help understand the underlying pathophysiology. After surgical decompression of the affected structures, symptoms can recover completely.

Background: Very small anterior communicating artery aneurysms (vsACoA) of <5 mm in size are detected in a considerable number of patients with aneurysmal subarachnoid hemorrhage (aSAH). Single-center studies report that vsACoA harbor particular risks when treated., Objective: To assess the clinical and radiological outcome(s) of patients with aSAH diagnosed with vsACoA after aneurysm treatment and at discharge., Methods: Information on n = 1868 patients was collected in the Swiss Subarachnoid Hemorrhage Outcome Study registry between 2009 and 2014. The presence of a new focal neurological deficit at discharge, functional status (modified Rankin scale), mortality rates, and procedural complications (in-hospital rebleeding and presence of a new stroke on computed tomography) was assessed for vsACoA and compared with the results observed for aneurysms in other locations and with diameters of 5 to 25 mm., Results: This study analyzed n = 1258 patients with aSAH, n = 439 of which had a documented ruptured ACoA. ACoA location was found in 38% (n = 144/384) of all very small ruptured aneurysms. A higher in-hospital bleeding rate was found in vsACoA compared with non-ACoA locations (2.8 vs 2.1%), especially when endovascularly treated (2.1% vs 0.5%). In multivariate analysis, aneurysm size of 5 to 25 mm, and not ACoA location, was an independent risk factor for a new focal neurological deficit and a higher modified Rankin scale at discharge. Neither very small aneurysm size nor ACoA location was associated with higher mortality rates at discharge or the occurrence of a peri-interventional stroke., Conclusion: Very small ruptured ACoA have a higher in-hospital rebleeding rate but are not associated with worse morbidity or mortality., (Copyright © Congress of Neurological Surgeons 2022. All rights reserved.)

Background/aim: Discontinuation of aspirin (ASA) prior to elective craniotomies is common practice. However, patients treated with ASA for secondary prevention bear a higher risk for thromboembolic complications. Aim of this systematic review is to investigate the risks and benefits of perioperative continuation and discontinuation of ASA in elective craniotomies., Methods: PubMed and Embase databases were searched. Inclusion criteria were retro- and prospective studies, reporting hemorrhagic and thromboembolic complications in patients in whom ASA was either continued or discontinued perioperatively in elective craniotomies. We excluded shunt operations and emergency cases. The MINORS (Methodological index for non-randomized studies) score was used to quantify the methodological quality of the eligible studies., Results: Out of 523 publications, 7 met the eligibility criteria (cumulative cohort of 646 patients). The mean MINORS score for the comparative studies was 18.7/24 (± SD 2.07, range: 17-22) and 9/16 for the unique non-comparative study, indicating an overall weak methodological quality of the included studies. 57.1% of the patients underwent craniotomy for intra- and extra-axial tumor removal, 39.0% for bypass surgery and 3.9% for neurovascular lesions (other than bypass). In 31.0% of the cases, ASA was prescribed for primary and in 69.0% for secondary prevention. ASA was continued perioperatively in 61.8% and discontinued in 38.2% of the cases. The hemorrhagic complication rate was 3% (95% CI [0.01-0.05]) in the ASA continuation group (Con-Group) and 3% (95% CI [0.01-0.09]) in the discontinuation group (Disc-Group) (p = 0.9). The rate of thromboembolic events in the Con-Group was 3% (95% CI [0.01-0.06]) in comparison to 6% (95% CI [0.02-0.14]) in the Disc-Group (p = 0.1)., Conclusion: Perioperative continuation of ASA in elective craniotomies does not seem to be associated with an increased hemorrhagic risk. The potential beneficial effect of ASA continuation on thromboembolic events needs to be further investigated in patients under ASA for secondary prevention., (© 2022. The Author(s).)

Background: The minipterional (MPT) craniotomy is a workhorse approach for clipping of middle cerebral artery (MCA) aneurysms. Because it aims to reach the skull base, traction on the temporal muscle is required. As a result, patients may suffer from transient postoperative temporal muscle discomfort. The sylvian keyhole approach (SKA) represents an alternative craniotomy for the clipping of MCA aneurysms. The aims of this study are to describe the operative technique of the SKA and to discuss the benefits and disadvantages compared to the MPT craniotomy., Methods: In this technical note, we report the experience gained with the SKA. This experience was acquired with virtual reality, 3D-printed models, and anatomical dissections. We also present two clinical cases., Results: The SKA is centered on the distal sylvian fissure and tailored toward the specific MCA aneurysm. Traction to the temporal muscle is not necessary because access to the skull base is not sought. With the SKA, dissection of the MCA is performed from distal to proximal, aiming for a proximal control at the level of the M1-segment. The limen insulae was identified as a key anatomical landmark for approach selection. The SKA offers good surgical maneuverability when the aneurysm is located at the level or distal to the limen. The MPT craniotomy, however, remains the most appropriate approach when the aneurysm is located proximal to the limen., Conclusion: The SKA represents a feasible and innovative alternative approach to the MPT craniotomy for surgical clipping of unruptured MCA aneurysms located at the level or distal to the limen insulae., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (© 2022 Rychen, Saemann, Gehweiler, Roethlisberger, Soleman, Hutter, Müller-Gerbl, Mariani and Guzman.)

Growing evidence links COVID-19 with acute and long-term neurological dysfunction. However, the pathophysiological mechanisms resulting in central nervous system involvement remain unclear, posing both diagnostic and therapeutic challenges. Here we show outcomes of a cross-sectional clinical study (NCT04472013) including clinical and imaging data and corresponding multidimensional characterization of immune mediators in the cerebrospinal fluid (CSF) and plasma of patients belonging to different Neuro-COVID severity classes. The most prominent signs of severe Neuro-COVID are blood-brain barrier (BBB) impairment, elevated microglia activation markers and a polyclonal B cell response targeting self-antigens and non-self-antigens. COVID-19 patients show decreased regional brain volumes associating with specific CSF parameters, however, COVID-19 patients characterized by plasma cytokine storm are presenting with a non-inflammatory CSF profile. Post-acute COVID-19 syndrome strongly associates with a distinctive set of CSF and plasma mediators. Collectively, we identify several potentially actionable targets to prevent or intervene with the neurological consequences of SARS-CoV-2 infection., (© 2022. The Author(s).)

Objective: Postoperative internal carotid artery (ICA) intimal flap (IF) is a potential complication after carotid endarterectomy (CEA) for carotid artery stenosis. There are no clear recommendations in the current literature on the management of this condition due to sparse evidence. Some authors advocate carotid stent placement or reoperation, while others suggest watchful waiting. The aim of this study was to analyze incidence and management strategies of postoperative ICA-IF, and moreover, to put these findings into context with a systematic literature review., Methods: The authors retrospectively reviewed all consecutive CEA cases performed at the University Hospital of Bern over a decade (January 2008 to December 2018). The incidence of postoperative ICA-IF, risk factors, management strategies, and outcomes were analyzed. These results were put into context with a systematic review following the PRISMA guidelines., Results: A total of 725 CEAs were performed between January 2008 and December 2018. Postoperative ICA-IF was detected by routine duplex neurovascular ultrasound (NVUS) in 13 patients, corresponding to an incidence rate of 1.8% (95% CI 1.0%-3.1%). There were no associated intraluminal thrombi on the detected IF. Intraoperative shunt placement was used in 5.6% and one or more intima tack sutures were performed in 42.5% of the 725 cases. There was no significant association between intraoperative shunt placement and the occurrence of an IF (p > 0.99). Two patients (15.4%) with IF experienced a transient postoperative neurological deficit (transient ischemic attack). In these cases, the symptoms resolved spontaneously without any interventions or change in the antiplatelet regimen. All other cases (84.6%) with IF were asymptomatic. In 1 patient (7.7%) with IF, the antiplatelet treatment was switched from a mono- to a dual-antiaggregating regimen because the IF led to a stenosis > 70%; this patient remained asymptomatic. All cases of IFs were managed conservatively with close radiological follow-up evaluations, without reoperation or stenting of the ICA. All 13 IFs vanished spontaneously after a mean duration of 6.9 months (median 1.5 months, range 0.5-48 months). A systematic literature review revealed a postoperative ICA-IF incidence of 3.0% (95% CI 2.1%-4.1%) with relatively heterogenous management strategies., Conclusions: Postoperative ICA-IF is a rare finding after CEA. Conservative therapy with close NVUS follow-up evaluations appears to be an acceptable and safe management strategy for asymptomatic IFs without associated intraluminal thrombi.

Background: Current prognostic tools in aneurysmal subarachnoid hemorrhage (aSAH) are constrained by being primarily based on patient and disease characteristics on admission., Objective: To develop and validate a complication- and treatment-aware outcome prediction tool in aSAH., Methods: This cohort study included data from an ongoing prospective nationwide multicenter registry on all aSAH patients in Switzerland (Swiss SOS [Swiss Study on aSAH]; 2009-2015). We trained supervised machine learning algorithms to predict a binary outcome at discharge (modified Rankin scale [mRS] ≤ 3: favorable; mRS 4-6: unfavorable). Clinical and radiological variables on admission ("Early" Model) as well as additional variables regarding secondary complications and disease management ("Late" Model) were used. Performance of both models was assessed by classification performance metrics on an out-of-sample test dataset., Results: Favorable functional outcome at discharge was observed in 1156 (62.0%) of 1866 patients. Both models scored a high accuracy of 75% to 76% on the test set. The "Late" outcome model outperformed the "Early" model with an area under the receiver operator characteristics curve (AUC) of 0.85 vs 0.79, corresponding to a specificity of 0.81 vs 0.70 and a sensitivity of 0.71 vs 0.79, respectively., Conclusion: Both machine learning models show good discrimination and calibration confirmed on application to an internal test dataset of patients with a wide range of disease severity treated in different institutions within a nationwide registry. Our study indicates that the inclusion of variables reflecting the clinical course of the patient may lead to outcome predictions with superior predictive power compared to a model based on admission data only., (Copyright © 2020 by the Congress of Neurological Surgeons.)

Objective: Early permanent cerebrospinal fluid (CSF) diversion for hydrocephalus during the first 2 weeks after aneurysmal subarachnoid hemorrhage (aSAH) shortens the duration of external ventricular drainage (EVD) and reduces EVD-associated infections (EVDAI). The objective of this study was to detect any association with symptomatic delayed cerebral vasospasm (DCVS), or delayed cerebral ischemia (DCI) by the time of hospital discharge. Methods: We used a single-center dataset of aSAH patients who had received a permanent CSF diversion. We compared an 'early group' in which the procedure was performed up to 14 days after the ictus, to a 'late group' in which it was performed from the 15 th day onward. Results: Among 274 consecutive aSAH patients, 39 (14%) had a permanent CSF diversion procedure with a silver-coated EVD. While the blood clot burden was similarly distributed, patients with early permanent CSF diversion (20 out of 39; 51%) had higher levels of consciousness on admission. Early permanent CSF diversion was associated with less colonized catheter, a shorter duration of extracorporeal CSF diversion (OR 0.73, 95%CI 0.58-0.92 per EVD day), and a lower rate of EVDAI (OR 0.08, 95%CI 0.01-0.80). The occurrence of CSF diversion device obstruction, the rate of symptomatic DCVS or detected DCI on computed tomography and the likelihood of a poor outcome at discharge did not differ between the two groups. Discussion: Early permanent CSF diversion lowers the occurrence of catheter colonization and infectious complication without affecting DCVS-related morbidity in good-grade aSAH patients. These findings need confirmation in larger prospective multicenter cohorts. Abbreviations: aSAH: aneurysmal subarachnoid hemorrhage; BNI: Barrow Neurological Institute Scale; CSF: Cerebrospinal fluid; DCVS: Delayed Cerebral Vasospasm; DCI: Delayed Cortical Ischemia; EKNZ: Ethik-Kommission Nordwest Schweiz; EVD: External ventricular drain; EVDAI: External ventricular drain-associated infections; GCS: Glasgow Coma Scale; IRB: Institutional Review Board; IVH: Inraventricular hemorrhage; mRS: Modified Rankin Scale; SOS: Swiss Study of Subarachnoid Hemorrhage Registry; WFNS: World Federation Neurological-Surgeon Scale.

Introduction: Management of spontaneous intracerebral hemorrhage (ICH) remains controversial despite efforts to produce high level evidence in the past few years. We systematically examined the pooled literature data on the natural history and surgical management of ICH., Evidence Acquisition: A systematic review was performed using the PubMed and Embase databases, encompassing English, full-text articles, reporting treatment outcomes for the conservative and surgical management of ICH., Evidence Synthesis: A total of 91 studies met the eligibility criteria (total of 16,411 ICH cases). The most common locations for an ICH were the basal ganglia for both the conservative (68.7%) and surgical cohorts (58.4%). Patients in the non-operative group (40.5%) were older (mean age 62.9 years; range 12.0-94.0), had a higher Glasgow Coma Scale (GCS) score at presentation (mean GCS 10.2; range 3-15) and lower ICH volume (mean 36.9 mL). When managed non-operatively, a favorable functional outcome was encountered in 25.7% (95% CI 16.9-34.5) of patients, with a 22.2% (95% CI 16.6-27.8) mortality rate. Patients who underwent surgery (59.5%) were younger (mean age 58.8 years; range 12.0-94.0), had a lower GCS at presentation (mean GCS 8.2; range 3-15) and larger ICH volume (mean 58.3 mL; range 8.2-140.0). Craniotomy with hematoma evacuation was the preferred surgical technique (38.6%). A favorable functional outcome was encountered in 29.8% (95% CI 23.8-35.8) of operated patients, with a 21.3% (95% CI 16.3-26.3) mortality rate., Conclusions: For many ICH cases, the reviewed literature allows to define surgical and conservative candidates. However, there are still some ICH-cases where management remains controversial.

Background: The supraorbital craniotomy (SOC) is classically performed through a skin incision in the patient's eyebrow. A variant with a skin incision in the patient's eyelid has become increasingly popular in recent years., Objective: To compare the transpalpebral and the transciliary variants of the SOC with regard to their potential role in aneurysm surgery., Methods: We carried out cadaveric dissections and virtual craniotomies on computerized tomography datasets. The skin incision, the craniotomy location and size, the working angles, and the achievable exposure of neurovascular structures were assessed and compared for both variants of the SOC., Results: The skin incision measured 4 cm for the transpalpebral and 3 cm for the transciliary variant. The skin could be retracted 1.5 cm upward from the lower edge of the orbital rim with the transpalpebral and 2.5 cm upward with the transciliary variant. The craniotomy size was 2.5 × 1.5 cm for both variants, given that the transpalpebral variant included an orbital osteotomy. The bony opening in the transpalpebral variant was 1 cm more caudal; this restricted the craniocaudal working angles and, thereby, limited the achievable exposure of neurovascular structures in the paraclinoid area and along the sphenoid ridge., Conclusion: If the orbital rim and the anterior aspect of the orbital roof are removed, then the transpalpebral variant of the SOC enables a bony opening that is just as large as that of the transciliary variant. Nonetheless, the more caudal location of the bony opening alters the available working angles and may impede exposure of key structures during aneurysm surgery., (Copyright © 2019 by the Congress of Neurological Surgeons.)

Background: Augmented reality (AR) applied to surgery refers to the virtual superimposition of computer-generated anatomical information on the surgical field. AR assistance in extracranial-intracranial (EC-IC) bypass revascularization surgery has been reported to be a helpful technical adjunct., Objective: To describe our experience of using AR in superficial temporal artery to middle cerebral artery (STA-MCA) bypass surgery with the additional implementation of new technical processes to improve the safety and efficacy of the procedure., Methods: Data sets from preoperative imaging were loaded and fused in a single 3-dimensional matrix using the neuronavigation system. Anatomical structures of interest (the STA, a selected M4 branch of the MCA, the middle meningeal artery [MMA], and the primary motor cortex [PMC]) were segmented. After the registration of the patient and the operating microscope, the structures of interest were projected into the eyepiece of the microscope and superimposed onto the patient's head, creating the AR surgical field., Results: AR was shown to be useful in patients undergoing EC-IC bypass revascularization, mostly during the following 4 surgical steps: (1) microsurgical dissection of the donor vessel (STA); (2) tailoring the craniotomy above the recipient vessel (M4 branch of the MCA); (3) tailoring the craniotomy to spare the MMA; and (4) tailoring the craniotomy and the anastomosis to spare the PMC., Conclusion: AR assistance in EC-IC bypass revascularization is a versatile technical adjunct for helping surgeons to ensure the safety and efficacy of the procedure., (Copyright © 2019 by the Congress of Neurological Surgeons.)

Objective : There is a relative lack of literature on long-term aneurysm recurrence and de novo aneurysm formation following surgical treatment of unruptured intracranial aneurysms. This retrospective single-center cohort study, therefore, analyzes the incidence of aneurysm recurrence, and the incidence of de novo aneurysms formation in patients with at least 10yrs of radiological follow-up. The data are put into the context of a systematic review of the literature. Methods : Patients that underwent surgical treatment of an unruptured intracranial aneurysm at the Basel University Hospital were retrospectively identified. The rate of recurrent or de novo aneurysm formation was assessed for all patients with imaging follow-up ≥10yrs. A systematic review including studies with a mean follow-up period of ≥10yrs was then performed. Results : A total of 95 patients had undergone surgical treatment of an unruptured intracranial aneurysm between 1994 and 2008. Twenty-one patients (22.1%) had available imaging follow-up ≥10yrs (mean: 13.1yrs). In these patients, aneurysm recurrence and de novo aneurysm formation were equally found in 23.8% (n = 5; 1.8%/yr). There was no case of aneurysm rupture from a recurrent or a de novo aneurysm. The systematic literature review covered a combined cohort of 1778 patients over a mean follow-up period of 14.0yrs. In this cohort, the aneurysm recurrence rate was 16.4% (0.7%/yr), and the rate of de novo aneurysm formation was 6.2% (0.4%/yr). Discussion : Despite some discrepancy regarding the incidence, both cohorts show a non-negligible long-term risk of aneurysm recurrence and de novo aneurysm formation, which warrants life-long imaging follow-up. Abbreviations: SD: standard deviation; DSA: digital subtraction angiography; CTA: computed tomography angiography; MRA: magnetic resonance angiography; MCA: middle cerebral artery; ACA: anterior cerebral artery; ACommA: anterior communicating artery; ICA: internal carotid artery; ADPKD: autosomal dominant polycystic kidney disease; MeSH: Medical Subject Headings.

In vestibular schwannoma (VS) surgery postoperative facial nerve (CN VII) palsy is reducing quality of life. Recently, we have introduced a surgical suction device for continuous dynamic mapping to provide feedback during tumor resection without switching to a separate stimulation probe. The objective was to evaluate the reliability of this method to avoid CN VII injury. Continuous mapping for CN VII was performed in large VS (08/2014 to 11/2017) additionally to standard neurophysiological techniques. A surgical suction-and-mapping probe was used for surgical dissection and continuous monopolar stimulation. Stimulation was performed with 0.05-2 mA intensities (0.3 msec pulse duration, 2.0 Hz). Postoperative CNVII outcome was assessed by the House-Brackmann-Score (HBS) after 1 week and 3 months following surgery. Twenty patients with Koos III (n = 2; 10%) and Koos IV (n = 18; 90%) VS were included. Preoperative HBS was 1 in 19 patients and 2 in 1 patient. Dynamic mapping reliably indicated the facial nerve when resection was close to 5-10 mm. One week after surgery, 7 patients presented with worsening in HBS. At 3 months, 4 patients' facial weakness had resolved and 3 patients (15%) had an impairment of CN VII (HBS 3 and 4). Of the 3 patients, near-total removal was attempted in 2. The continuous dynamic mapping method using an electrified surgical suction device might be a valuable additional tool in surgery of large VS. It provides real-time feedback indicating the presence of the facial nerve within 5-10 mm depending on stimulation intensity and may help in avoiding accidental injury to the nerve.