The outcome of surgical management for the patient with giant occipital encephalocele: a case illustration and systematic review.

PURPOSE: Occipital encephalocele (OE) is one of congenital malformation of the central nervous system. However, giant OE, mostly defines as bigger-than-head OE, is extremely rare and carries a worse prognosis. Here, we presented our systematic review of the management of the giant OE and illustrated our case. METHOD: The systematic review was carried out under PRISMA guidelines. Publications were searched under "occipital encephalocele" from 1959 to April 2021. Our primary area of interest was the outcome of patients who have undergone surgery for giant OE. Variables of interest included age, sex, size of the sac, presentations, associated anomalies, management, outcome, and follow-up period were collected. RESULT: We collected 35 articles, consisting of 74 cases (including 1 case from our illustrative case), to perform a systematic review. The mean age at the time of surgery was 3.53 ± 8.22 months. The mean circumference of the sac was 52.41 ± 18.6 cm. The three most common associated anomalies were microcephaly, corpus callosal agenesis/dysgenesis, and Chiari malformation. After the surgery, survival was reported in 64 (90.1%) patients. Postoperative complications were reported in 14 cases (16 events). Age above 1 month at the time of surgery was significantly associated with survival (p = 0.02) but not with complication (p = 0.22). In contrast, the type of surgery was not associated with survival (p = 0.18) or complications (p = 0.41). CONCLUSION: Despite a rare condition with a poor prognosis, our reported case and systematic review revealed promising outcomes of surgery regardless of surgical strategies, especially in patients older than 1 month. Thus, appropriate planning is essential for the treatment of this condition.

Bleeding pediatric AVM with negative pre-operative angiography: the first case report.

INTRODUCTION: Pediatric arteriovenous malformation (pAVM) is one of the most common vascular entities in non-traumatic intracerebral hemorrhage (ICH) in children. To diagnose arteriovenous malformation (AVM), digital subtraction angiography (DSA) is the gold standard investigation because it can provide sufficient dynamic information about the AVM. In extremely rare occasions, angiography is unable to detect an AVM because the AVM is spontaneously occluded. All reported cases found by authors in the literature had already been diagnosed with AVM by angiography or other vascular studies before the AVM occlusion. CASE PRESENTATION: We present a case of a 4-year-old girl who presented with left occipital ICH with atypical calcification. Based on history and investigation, pAVM was the most likely diagnosis. However, preoperative angiography was negative for pAVM and for shunting. Bleeding tumor was then suspected instead. After resection, pathological diagnosis confirmed pAVM. CONCLUSION: Our case demonstrates that DSA, despite being considered the gold standard, cannot always diagnose pAVM. The mechanism of spontaneous AVM occlusion remains unknown.

Efficacy and predicting factors of multimodal treatment for ruptured intracranial vertebral artery dissecting aneurysms.

We aimed to investigate the efficacy of our multimodal strategies and propose a treatment algorithm for ruptured vertebral artery dissecting aneurysms (VADAs). This study included 41 patients treated at a single institution between 2015 and 2022. The treatment modalities were justified based on the collateral circulation and aneurysm location related to the posterior inferior cerebellar artery (PICA). Treatment outcomes and complications of each treatment group were analyzed. The association between the collateral blood flow and the postoperative vertebrobasilar ischemia (VBI) was also investigated. There were 17 post-PICA, 10 PICA-involved, 7 pre-PICA, and 7 non-PICA types. Reconstruction techniques included flow diversion devices (n = 11) and stent-assisted coiling (n = 3). Deconstruction techniques included coil trapping (n=17) and microsurgical parent artery occlusion with (n = 8) or without PICA revascularization (n = 2). Five (18.5%) of the deconstruction group had postoperative VBI. Overall favorable outcomes in both groups were observed in 70.7% of patients with a mean follow-up time of 21.5 months. Poor World Federation of Neurosurgical Societies grade (IV-V) was identified as a predictor of unfavorable outcomes (p = 0.003). In addition, the VA4/BA4 ratio > 0.22, the presence of collateral blood flow from the posterior communicating artery (PcomA), and a contralateral VA diameter > 2.5 mm were associated with a lower risk of postoperative VBI. In summary, the proposed strategic treatment in this study is pragmatic, yielding satisfactory results where a deconstructive technique should be used with caution, particularly when there is a flow mismatch or the absence of collateral PcomA in the vertebrobasilar circulation.

Treatment outcomes between endoscopic surgery and conventional craniotomy for spontaneous supratentorial intracerebral hemorrhage: a randomized controlled trial.

Minimally invasive surgery (MIS) has been repeatedly evaluated in patients with ICH as a promising procedure for improved survival and functional outcome. Among MIS techniques, endoscopic surgery (ES) has shown superior efficacy for ICH removal due to rapid clot evacuation and immediate bleeding control. However, the results of ES are still uncertain due to insufficient data. In this study, participants with spontaneous supratentorial ICH who were indicated for surgery were randomly assigned (1:1) to undergo ES or conventional craniotomy (CC) between March 2019 and June 2022. The primary outcome was a difference in favorable modified Rankin Scale (mRS) outcome (0 to 3) at 180-day follow-up evaluated by blind assessors. There were 188 participants, 95 in the ES group and 93 in the CC group, who completed the trial. At 180-day follow-up, 46 (48.4%) participants in the ES group achieved favorable outcomes, compared to 33 (35.5%) in the CC group (risk difference [RD] 12.9, 95% CI - 1.1-27.0, p = 0.07). After covariate adjustment, the difference was slightly higher and significant (adjusted RD 17.3, 95% CI [4.6-30.0], p = 0.01). Moreover, the ES group had less operative duration and less intraoperative blood loss than the CC group. Clot evacuation rate and complications were similar between the two groups. Subgroup analyses showed a potential benefit of ES in age < 60 years, time to surgery ≥ 6 h, and deep ICH. This study showed that ES was safe and effective in ICH removal and provided a better functional outcome compared to CC.

Recent Update on Carotid Endarterectomy versus Carotid Artery Stenting.

Carotid artery stenosis (CS) is a major cause of ischemic stroke. Treatment of CS consists of best medical treatment and carotid revascularization (CR), including carotid endarterectomy (CEA) and carotid artery stenting (CAS). Both CR techniques have their own procedural risks. Therefore, selection of the appropriate treatment for patients with CS is relatively complicated. Many studies and guidelines have reported the efficacy of each treatment for both symptomatic and asymptomatic patients. However, the results are still controversial, especially concerning the efficacy and safety of CEA and CAS. In this paper, we review and discuss the current evidence and compare results from studies of CEA and CAS, including major randomized trials, meta-analyses and ongoing trials. Moreover, based on the current data, we propose a new comprehensive decision-making for the management of CS.

Cerebellopontine angle medulloblastoma with extensive nodularity in a child: case report and review of the literature.

BACKGROUND: Cerebellar medulloblastomas (MBs) are one of the most common posterior fossa tumors in children but rarely occur in the cerebellopontine angle (CPA). Only 39 cases of CPA MBs were reported in the literature, and most of them were classic and desmoplastic MBs. CASE PRESENTATION: A 22-month-old girl presented with progressive cerebellar ataxia. Magnetic resonance imaging showed a large tumor in the right CPA and obstructive hydrocephalus. Surgical resection was performed and achieved total tumor removal. Microscopic examination and immunohistochemical staining revealed the diagnosis of MB with extensive nodularity. The patient recovered from her symptoms during follow-up and was transferred for adjuvant chemotherapy. CONCLUSION: MB should be considered as a differential diagnosis of a lesion in the CPA. The treatment and outcome of CPA MBs are similar to cerebellar MBs.

Factors predicting outcomes of endoscopic endonasal approach in craniopharyngioma patients.

Objectives: Endoscopic endonasal approach (EEA) is commonly used for resection of craniopharyngioma (CP). Treatment outcomes of EEA for CP were related to numerous factors; however, they have been evaluated in few studies. The objective of this study is to investigate factors associated with the outcomes of CP following this operation. Materials and Methods: The records of patients with CP, who underwent EEA at our institution from January 2014 to June 2022, were retrospectively reviewed. Surgical outcomes, including the extent of resection, visual recovery, and endocrinological outcomes, were reported. Clinical and radiographic factors were analyzed for their associations with treatment outcomes using logistic regression analyzes. Results: This study cohort consisted of 28 patients with CP. Gross total resection (GTR) was achieved in 12 patients (43%). Post-operative visual status improved, stabilized, and deteriorated in 89%, 6%, and 6% of the patients, respectively. There were no patients recovered from pre-operative pituitary dysfunctions, while post-operative hypoadrenalism, hypothyroidism, and hypogonadism were found in 9 (36%), 11 (42%), and 4 (22%) patients, respectively. Post-operative permanent diabetic insipidus was found in 13 patients (50%). Greater suprasellar extension of the tumor was associated with a lower rate of GTR (P = 0.011). Diabetes mellitus (DM) was associated with poor visual recovery (P = 0.022). Larger tumor size and Puget grade 2 were associated with postoperative hypoadrenalism (P = 0.01 and 0.023, respectively). In addition, Puget grade 2 was associated with post-operative hypothyroidism (P = 0.017). Conclusion: For EEA in CP, the extent of resection could be determined by suprasellar extension of the tumor. DM was a poor predicting factor for visual recovery, while larger tumors and Puget grade 2 had a higher risk of post-operative hypopituitarism.

Comparison of adjunctive middle meningeal artery embolization using embosphere particles versus surgical drainage alone for the treatment of chronic subdural hematoma: A prospective study.

BACKGROUND: Middle meningeal artery embolization (MMAE) has emerged as a primary and adjunctive therapy for chronic subdural hematoma (CSDH) in addition to conventional treatment. However, there is a scarcity of data that explicitly compares the effectiveness of adjunctive MMAE to surgical drainage alone (SDA), as well as the use of Embosphere particles. The objective of this study was to assess the safety and efficacy of adjunctive MMAE in the treatment of symptomatic CSDH compared to SDA. METHODS: This prospective study included 43 patients with 52 CSDH sides, treated at a single institution between 2022 and 2023. The primary outcome was postoperative hematoma volume at 14, 30, 90, and 180 days after surgical drainage, which was analyzed using the generalized estimating equation. The secondary outcomes were the complications and recurrence/reoperation rate. Adjunctive MMAE was performed within 7 days following the surgery, utilizing Embosphere as the embolic material. RESULTS: The patients were assigned to either the adjunctive MMAE group (n = 20, 26 CSDH sides) or the SDA group (n = 23, 26 CSDH sides). The adjunctive MMAE group demonstrated a more significant reduction in hematoma volume (p = 0.007) and maximal hematoma thickness (p = 0.016) at all follow-up intervals. A trend towards lower recurrence and reoperation rates was observed with adjunctive MMAE; particularly, none of the patients in the adjunctive MMAE group experienced a recurrence of CSDH, compared to 19.2 % in the SDA group (p = 0.051). One procedural-related complication (3.8 %) in the adjunctive MMAE group. CONCLUSION: Our results suggested that adjunctive MMAE, compared to SDA, may enhance hematoma resolution and reduce the need for reoperation due to recurrence.

Optimizing Management of Cavernous Sinus Meningiomas: A Novel Strategy Integrating Endoscopic Endonasal and Transorbital Surgery with Adjuvant Stereotactic Radiotherapy.

BACKGROUND: Cavernous sinus meningiomas (CSMs) are challenging skull base tumors due to their proximity to vital neurovascular structures. Traditional aggressive transcranial resection often leads to significant morbidities with limited improvement of cranial nerve (CN) deficits. Recent advancements in endoscopic skull base surgery and stereotactic radiation therapy (SRT) offer a more conservative approach, facilitating tumor decompression while preserving critical structures. METHODS: This retrospective study reviewed medical records of patients with symptomatic CSMs who underwent endoscopic endonasal and/or transorbital surgery, followed by adjuvant SRT, at our institution between January 2017 and April 2022. Patient demographics, tumor characteristics, surgical approaches, radiation, treatment outcomes, complications, and follow-up time were analyzed. RESULTS: Thirty-nine patients with CSMs were included. Endoscopic endonasal approach was performed in 24 patients (61.5%), endoscopic transorbital approach in 10 patients (25.6%), and combined approaches in 5 patients (12.8%). Adjuvant SRT was administered to 79.5% of patients. Postoperative outcomes showed recovery of CN 3-6 deficits and vision in 60.9% and 65% of cases, respectively. Complications included postoperative CN 3-6 deficits in 5 cases and postradiation visual deterioration in 1 case. During a mean follow-up period of 44 months, tumor progression occurred in 4 patients (10.3%), with 3 diagnosed as World Health Organization grade II meningiomas and 1 as World Health Organization grade I. CONCLUSIONS: This study supports the use of endoscopic skull base surgery combined with adjuvant SRT for symptomatic CSMs, demonstrating both safety and efficacy. This approach yielded favorable outcomes in symptom improvement, tumor control, and positive safety profile.

Effectiveness of a multimodal strategy to reduce external ventricular drain-associated infection: A quasi-experimental study.

BACKGROUND: Infection is a serious complication in neurosurgical patients who undergo external ventricular drain (EVD) insertion. METHODS: We conducted a quasi-experimental study in patients who underwent EVD insertion to evaluate the impact of a multi-modal strategy to reduce the incidence of external ventricular drain associated infections (EVDAIs). The study was divided into 2 periods; (1) the pre-intervention period when techniques for EVD insertion and maintenance were up to the discretion of the neurosurgeons and (2) the post-intervention after implementation of a multi-modal strategy (cefazolin antibiotic prophylaxis, preoperative chlorhexidine showers, application of postoperative chlorhexidine-impregnated dressing, limited manipulation of the EVD, and meticulous EVD management). The primary outcome was the incidence rate of EVDAIs; secondary outcomes included in-hospital mortality rate, the hospital length of stay. RESULTS: In total, 135 patients were included. The incidence rate of EVDAIs was significantly reduced in the post-intervention period (5.6 cases/1,000 EVD-days) compared with the pre-intervention period (18.2 cases/1,000 EVD-days; P=0.026). There were no differences in all secondary outcomes analyzed. This multi-modal strategy was associated with high satisfaction among health care personnel. CONCLUSIONS: Implementation of a multi-modal strategy was associated with a reduction in the incidence of EVDAIs. This was in line with our goal of promoting a new culture of safety despite being in a resource-limited setting.

Prediction of Permanent Shunt Dependency in Patients with Intraventricular Hemorrhage: Outcomes of Early External Ventricular Drainage Weaning Protocol.

BACKGROUND: Hydrocephalus remains a common sequela of intraventricular hemorrhage (IVH) despite adequate drainage of the hematoma, including endoscopic surgery, intraventricular fibrinolysis, and external ventricular drainage (EVD). Moreover, the appropriate timing for conversion from EVD to ventriculoperitoneal shunt (VPS) is uncertain. This study aimed to evaluate the predictors of shunt dependency in patients with IVH based on the early EVD weaning protocol in our institution. METHODS: We retrospectively reviewed medical records of patients who were diagnosed with primary IVH and secondary IVH from spontaneous intracerebral hemorrhage during the period 2018-2021. Predictors associated with shunt dependency were identified using a logistic regression model. The cutoff point of each variable was selected by receiver operating characteristic curve analysis. Furthermore, shunt complications were reported as a safety measure of our early EVD weaning protocol. RESULTS: The analysis included 106 patients. After IVH treatment, 15 (14%) patients required ventriculoperitoneal shunt, whereas 91 (86%) patients were shunt-free. The diameter of posttreatment temporal horn and the degree of IVH reduction were the significant predictors of shunt dependency. Moreover, patients with IVH reduction of >45% and temporal horn diameter of <9 mm had a lower probability of shunt dependency. Shunt failure was found in 2 (13.3%) patients. CONCLUSIONS: This study showed that a large temporal horn diameter and a lower degree of IVH removal were predictors of shunt dependency in patients with IVH. In addition, early conversion from EVD to ventriculoperitoneal shunt is safe and feasible.

Safety and efficacy of continuous intravenous labetalol for blood pressure control in neurosurgical patients.

OBJECTIVES: Current evidence supporting the use of continuous intravenous labetalol for blood pressure (BP) control in neurosurgical patients is limited. This study aims to assess the efficacy and safety of labetalol in neurosurgical patients and identify potential contributing factors to these outcomes. METHODS: We retrospectively reviewed the medical records of neurosurgical patients who received continuous labetalol infusion for BP control. Efficacy was assessed based on the time needed to achieve the target BP (systolic BP ≤ 140 mmHg or diastolic BP ≤ 90 mmHg). Safety was assessed according to adverse events that occurred during labetalol administration. Factors associated with efficacy and safety were analyzed using a logistic regression model. RESULTS: Among 79 patients enrolled in this study, 47 (59.49%) achieved the target BP within 1 hour (early response). No factors were significantly associated with an early response. Hypotension was observed in 11 patients (13.9%), and bradycardia was observed in 8 patients (10.1%). Hypotension was significantly associated with patient age and motor impairment, while bradycardia was significantly associated with diabetes mellitus. CONCLUSION: The efficacy and safety profiles of labetalol infusion suggest this treatment as a promising option for BP control in neurosurgical patients.

Outcomes of Combined Endoscopic Surgery and Fibrinolytic Treatment Protocol for Intraventricular Hemorrhage: A Randomized Controlled Trial.

BACKGROUND: Intraventricular fibrinolysis (IVF) and endoscopic surgery (ES) are the new promising treatment strategies to enhance the rate of hematoma clearance, which might improve functional outcome. This study investigated and compared the outcomes among these interventions. METHODS: A randomized (1:1) double-blinded trial was carried out between August 2018 and December 2021. The intervention and control groups comprised patients receiving IVF and/or ES and external ventricular drainage (EVD), respectively. All participants had experienced primary or secondary intraventricular hemorrhage (IVH) from spontaneous intracerebral hemorrhage with obstructive hydrocephalus complications. The primary outcome was modified Rankin Scale score 180 days post treatment. Interim assessments were planned for every 50 participants enrolled to ensure safety and efficacy. RESULTS: After enrollment of 110 participants (55 participants in each group), there was a difference in 30-day mortality (2 [3.6%] vs. 13 [32.7%] in the EVD group, P = 0.002), reaching the predetermined boundaries for termination of the trial. We demonstrated a better favorable outcome (modified Rankin Scale score 0-3) at 180 days in the intervention group, compared with the control group (35 [63.6%] vs. 24 [43.6%], P = 0.04). Participants in the intervention group experienced a higher IVH removal rate (91% [9.0] vs. 69.5% [38.0], P < 0.01) and had lower shunt conversion (1 [1.8%] vs. 16 [29.3%], P < 0.01). Treatment complications were comparable between the two groups. CONCLUSIONS: This study demonstrated that combined ES and IVF is safe and effective for the treatment of IVH. In addition, it concluded that aggressive but safe procedures used to remove IVH could improve clinical outcome in patients with IVH.

Applications of Machine Learning Model for Prediction of Outcomes in Primary Pontine Hemorrhage.

BACKGROUND: Primary pontine hemorrhage (PPH) is a rare intracranial hemorrhage with a wide range of mortality rate. Predicting the prognosis of PPH is still challenging. Previous prognostic scoring tests have not been widely used due to limited external validation. This study applied machine learning (ML) algorithms to develop predictive models for mortality and prognosis of patients with PPH. METHODS: Data of patients with PPH were retrospectively reviewed. Seven ML models were used to train and validate for predicting outcomes of PPH including 30-day mortality rate, 30-day, and 90-day functional outcomes. Accuracy, sensitivity, specificity, positive and negative predictive value, F1 score, Brier score, and area under the curve (AUC) of the receiver operating characteristic were calculated. The models with the highest AUC were then selected to evaluate the testing data. RESULTS: One hundred and fourteen patients with PPH were included. Mean hematoma volume was 7 ml and most patients had hematoma in the central part of the pons. The 30-day mortality rate was 34.2% and favorable outcomes were observed in 71.1% and 70.2% during 30-day and 90-day follow-up. The ML model could predict 30-day mortality with an AUC of 0.97 using an artificial neural network. Regarding functional outcome, the gradient boosting machine could predict both 30-day and 90-day outcomes with an AUC of 0.94. CONCLUSIONS: ML algorithms achieved a high performance and accuracy in predicting PPH outcomes. Despite the need for further validation, ML models are promising tools for clinical applications in the future.

Quantitative Comparative Analysis of the Endoscope-Assisted Expanded Retrosigmoid Approach and the Far-Lateral Approach to the Inframeatal Area: An Anatomic Study With Surgical Implications.

BACKGROUND: The inframeatal area (IFMA) is a complex anatomic region of the posterior cranial fossa. Given its deep-seated location, tumors involving the IFMA represent a surgical challenge. OBJECTIVE: To objectively compare the endoscope-assisted expanded retrosigmoid approach (ERSA) and the far-lateral supracondylar transtubercular approach (FLTA) to address the IFMA. METHODS: Anatomic dissections were performed on 5 cadaveric heads (10 sides). The ERSAs were performed before and after the FLTAs. The surgical exposure, surgical freedom, and angles of attack to the IFMA were measured and compared for each approach. In addition, 2 illustrative clinical cases are reported. RESULTS: Compared with FLTA, ERSA yielded a nonsignificantly smaller mean area of exposure, whereas FLTA provided a significantly larger mean area of surgical freedom, compared with ERSA ( P = .002). The mean horizontal and vertical angles of attack were significantly different between the approaches. In the vertical plane, FLTA yielded the broadest angle of attack at the root entry zone of the lower cranial nerves (CN; P < .004), whereas ERSA did so at the dural entry zone of CN VII/VIII ( P = .006). In the horizontal plane, FLTA achieved its broadest angle of attack at the root entry zone of the lower CNs ( P = 1.83) while ERSA at the dural entry zone of CN VII/VIII ( P = .37). CONCLUSION: ERSA and FLTA granted a comparable exposure with the IFMA. Although FLTA may afford a larger area of surgical freedom, ERSA may be a suitable alternative to approach the IFMA, particularly to reach the most medial and superior aspects of this region. Conversely, FLTA may facilitate access to more caudally targets.

The "Crista Ovale": A Reliable Anatomical Landmark in Transorbital Endoscopic Approaches to the Middle Cranial Fossa.

BACKGROUND: Transorbital endoscopic approaches (TOEAs) have emerged as adjunct and alternatives for accessing the middle cranial fossa (MCF). Nuances of the skull base anatomy from a ventral transorbital endoscopic viewpoint remain to be fully described. OBJECTIVE: To assess the anatomy of the "crista ovale" (COv), described transcranially as the midsubtemporal ridge (MSR), from a ventral transorbital perspective and evaluate its role as a landmark in TOEA to the MCF. METHODS: Lateral TOEAs to the MCF were performed in 20 adult cadaveric heads (40 sides). The presence of the COv/MSR was evaluated under endoscopic visualization. Anatomic relationships between COv/MSR and surrounding structures were assessed. The presence of COv/MSR was also examined in 30 cadaveric head computed tomography (CT) scans (60 sides). RESULTS: The COv/MSR was identified in 98% (39/40) of sides at the MCF, as 1 of 4 major configurations. The COv/MSR was found anterolateral to the foramen ovale and foramen spinosum (mean distance: 9.2 ± SD 2.4 mm and 12.3 ± SD 2.6 mm, respectively) directly anterior or anteromedial to the petrous apex (mean distance: 26.2 ± SD 2.6 mm) and at a mean 47.6 ± SD 4.7 mm from the approach's surgical portal. It was recognized in 95% (57/60) of CT scans. CONCLUSION: The COv/MSR can be readily identified during TOEA to the MCF and on CT. It serves as a reliable landmark to localize the foramen ovale, foramen spinosum, and petrous apex. Further studies may confirm its surgical significance in transorbital endoscopic procedures.

Endoscopic Approaches to the Paramedian Skull Base: An Anatomic Comparison of Contralateral Endonasal and Transmaxillary Strategies.

BACKGROUND: The expanded endoscopic endonasal approach (EEA) is limited laterally by the internal carotid artery (ICA). The EEA to the paramedian skull base often requires complex maneuvers such as dissection of the Eustachian tube (ET) and foramen lacerum (FL), and ICA manipulation. An endoscopic contralateral transmaxillary approach (CTMA) has the potential to provide adequate exposure of the paramedian skull base while bypassing manipulation of the aforementioned anatomic structures. OBJECTIVE: To quantify and compare the surgical nuances of a CTMA and a contralateral EEA when approaching the paramedian skull base in cadaveric specimens. METHODS: Five adult cadaveric heads were dissected bilaterally (10 sides) using a contralateral EEA and a CTMA to expose targets of interest at the paramedian skull base. For each target in both approaches, the surgical freedom, angle of attack, the corridor's "perspective angle," and "turning angle" to circumvent the ICA, ET, and FL were obtained. RESULTS: The CTMA achieved superior surgical freedom at all targets ( P < .05) except at the root entry point of cranial nerve XII. The CTMA provided superior vertical and horizontal angles of " attack " to the majority of targets of interest. Except when approaching the root entry point of cranial nerve XII, the CTMA " turning angle " around the ICA, ET, and FL were wider with CTMA for all targets. CONCLUSION: A CTMA complements the EEA to access the paramedian skull base. A CTMA may limit the need for complex maneuvers such as ICA mobilization and dissection of the ET and FL when approaching the paramedian skull base.

Transorbital Approach for Olfactory Groove Meningioma.

The transorbital endoscopic approach has been increasingly employed in the management of skull base disease.1-4 We present a case of a 48-year-old woman with a 2-month history of progressively worsening headache referred to our neurosurgery division after a new-onset generalized seizure. On examination, she was found to have diminished olfaction with no additional findings, including no visual or cognitive deficits. Preoperative imaging revealed a large anterior fossa mass originating at the left olfactory groove with leftward extension and prominent anterior and posterior ethmoidal arterial feeders. A left-sided transorbital approach was planned to address the tumor. The lesion was resected without incident using a pure transorbital endoscopic technique. The microscope was brought into the field at the end of the procedure to aid with hemostasis of the surgical bed. The patient recovered without surgical complications. Histopathology revealed a World Health Organization grade I olfactory groove meningioma. Postoperative imaging confirmed gross total tumor resection without evidence of recurrence. This case highlights the application of the transorbital endoscopic approach in the management of anterior cranial base tumors. Advantages of this approach include minimal invasive access, avoidance of brain retraction, and ease for early tumor devascularization.