Category: skull base surgery

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Anterior transpetrosal approach: experiences in 274 cases over 33 years. Technical variations, operated patients, and approach-related complications

J Neurosurg 136:413–421, 2022

The anterior transpetrosal approach (ATPA) was initially reported in 1985. The authors’ institution has 274 case records of surgery performed with the ATPA during the period from 1984 to 2017. Although many technical advances and modifications in the ATPA have occurred over those 33 years, to the authors’ knowledge no articles to date have reported a detailed analysis of variations and complications of the ATPA. In this study, the authors analyzed their patient series to elucidate improvements over time in ATPA methodology while highlighting unresolved problems and evaluating how to avoid surgical complications.

METHODS All surgical cases (274 patients) using the ATPA at the authors’ institution during the period from 1984 to 2017 were analyzed retrospectively using charts, clinical summaries, operative records, and operative videos. Obtained parameters were patient age and sex, diagnosis, size of tumors, location of disease, operative date, neurological symptoms before and after surgery, radiographically identified brain injury, and other surgical complications. The most common diagnosis was petroclival meningioma (n = 158), followed by trigeminal schwannoma (n = 32), chordoma (n = 25), epidermoid tumor (n = 21), other tumor (n = 27), aneurysm (n = 6), and other (n = 5).

RESULTS The original ATPA was performed in 239 cases. In an additional 35 cases, a modified ATPA was performed. Zygomatic osteotomy with ATPA was a common modification that was used in 19 of the 35 cases to decrease retraction damage to the temporal lobe for high-positioned tumors. Brain injury by temporal lobe retraction without venous hemorrhage still occurred in 8 of the 19 cases (3.1%) with surgical death in 1 of these cases (0.4%) of reoperation with sacrifice of the petrosal vein. Symptomatic CSF leak was the most frequent complication noted and was observed in 35 cases (13.5%). In most of these cases the patients were cured by observation or lumbar drain, but in 6 cases (17.1%) reoperation was needed. Facial nerve damage related to surgical approach decreased from 6.2% to 3.5% after 2010; however, the incidence of CSF leaks (13.5%) has not improved.

CONCLUSIONS There have been several modifications and advancements made in the ATPA to increase tumor removal and decrease surgical complications. However, complications related to surgical approach occurred, such as venous occlusion–related brain injury and facial nerve damage at pyramid resection. CSF leak remained an unsolved problem related to the ATPA procedures. Preoperative assessment of venous variation of the middle fossa, pneumatization of the temporal bone, and intraoperative monitoring of cranial nerves are important procedures to decrease these complications.

 

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Complications after 1002 endoscopic endonasal approach procedures at a single center: lessons learned, 2010–2018

https://doi.org/10.3171/2020.11.JNS202494

The endoscopic endonasal approach (EEA) has evolved into a mainstay of skull base surgery over the last two decades, but publications examining the intraoperative and perioperative complications of this technique remain scarce. A prior landmark series of 800 patients reported complications during the first era of EEA (1998–2007), parallel to the development of many now-routine techniques and technologies. The authors examined a single-institution series of more than 1000 consecutive EEA neurosurgical procedures performed since 2010, to elucidate the safety and risk factors associated with surgical and postoperative complications in this modern era.

METHODS
After obtaining institutional review board approval, the authors retrospectively reviewed intraoperative and postoperative complications and their outcomes in patients who underwent EEA between July 2010 and June 2018 at a single institution.

RESULTS
The authors identified 1002 EEA operations that met the inclusion criteria. Pituitary adenoma was the most common pathology (n = 392 [39%]), followed by meningioma (n = 109 [11%]). No patients died intraoperatively. Two (0.2%) patients had an intraoperative carotid artery injury: 1 had no neurological sequelae, and 1 had permanent hemiplegia. Sixty-one (6.1%) cases of postoperative cerebrospinal fluid leak occurred, of which 45 occurred during the original surgical hospitalization. Transient postoperative sodium dysregulation was noted after 87 (8.7%) operations. Six (0.6%) patients were treated for meningitis, and 1 (0.1%) patient died of a fungal skull base infection. Three (0.3%) patients died of medical complications, thereby yielding a perioperative 90-day mortality rate of 0.4% (4 deaths). High-grade (Clavien-Dindo grade III–V) complications were identified after 103 (10%) EEA procedures, and multivariate analysis was performed to determine the associations between factors and these more serious complications. Extradural EEA was significantly associated with decreased rates of these high-grade complications (OR [95% CI] 0.323 [0.153–0.698], p = 0.0039), whereas meningioma pathology (OR [95% CI] 2.39 [1.30–4.40], p = 0.0053), expanded-approach intradural surgery (OR [95% CI] 2.54 [1.46–4.42], p = 0.0009), and chordoma pathology (OR [95% CI] 9.31 [3.87–22.4], p < 0.0001) were independently associated with significantly increased rates of high-grade complications.

CONCLUSIONS
The authors have reported a large 1002-operation cohort of EEA procedures and associated complications. Modern EEA surgery for skull base pathologies has an acceptable safety profile with low morbidity and mortality rates. Nevertheless, significant intraoperative and postoperative complications were correlated with complex intradural procedures and meningioma and chordoma pathologies.

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Morphometric Study of the Posterior Fossa: Identification of Practical Parameters for Tailored Selection of Surgical Routes to the Petroclival Region

J Neurol Surg B Skull Base 2022;83:37–43

The petroclival region is an integral part of the skull base. It can harbor different pathologies and provides access to the petroclival junction and cerebellopontine angle. We present the results of the morphometric analysis of the posterior fossa and a prediction model to enable skull base surgeons to choose an optimal surgical corridor considering patient’s bony anatomy.

Methods Ninety patients (14 to assess interobserver reliability) with temporal bone computed tomography were selected. Exclusion criteria included patients <18 years of age, radiographic evidence of trauma, infection, or previous surgery. The images were analyzed using OsiriX MD (Bernex, Switzerland). We recorded clival length, vertical angle, and surface area, and petroclival angle, petrous apex, and translabyrinthine corridors volume.

Results The average age was 49.5 years (55%) for males. The mean clival length and surface areas were 44.2mm (standard deviation [SD]   4.1) and 8.1 cm2 (SD   1.3). The mean petrous apex and translabyrinthine corridors volumes were 2.2 cm3 (SD   0.6) and 10.1 cm3 (SD   3.7). The mean petroclival angle at the internal auditory canal (IAC) was 154.9 degrees (SD   9). The clival length correlated positively with clival surface area (rho   0.6, p <0.05), petrous apex volume (rho   0.3, p < 0.05), and translabyrinthine volume (rho   0.3, p < 0.05).

Conclusion The petroclival region is complex and with high variability of surgical significance. The use of preoperative measurements of the clival length and petroclival angle as part of surgical planning that could help the surgeon to choose an optimal surgical corridor by overcoming the anatomical variability elements.

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Endoscopic endonasal versus transcranial surgery for primary resection of craniopharyngiomas based on a new QST classification system

J Neurosurg 135:1298–1309, 2021

An assessment of the transcranial approach (TCA) and the endoscopic endonasal approach (EEA) for craniopharyngiomas (CPs) according to tumor types has not been reported. The aim of this study was to evaluate both surgical approaches for different types of CPs.

METHODS A retrospective review of primary resected CPs was performed. A QST classification system based on tumor origin was used to classify tumors into 3 types as follows: infrasellar/subdiaphragmatic CPs (Q-CPs), subarachnoidal CPs (S-CPs), and pars tuberalis CPs (T-CPs). Within each tumor type, patients were further arranged into two groups: those treated via the TCA and those treated via the EEA. Patient and tumor characteristics, surgical outcomes, and postoperative complications were obtained. All variables were statistically analyzed between surgical groups for each tumor type.

RESULTS A total of 315 patients were included in this series, of whom 87 were identified with Q-CPs (49 treated via TCA and 38 via EEA); 56 with S-CPs (36 treated via TCA and 20 via EEA); and 172 with T-CPs (105 treated via TCA and 67 via EEA). Patient and tumor characteristics were equivalent between both surgical groups in each tumor type. The overall gross-total resection rate (90.5% TCA vs 91.2% EEA, p = 0.85) and recurrence rate (8.9% TCA vs 6.4% EEA, p = 0.35) were similar between surgical groups. The EEA group had a greater chance of visual improvement (61.6% vs 35.8%, p = 0.01) and a decreased risk of visual deterioration (1.6% vs 11.0%, p < 0.001). Of the patients with T-CPs, postoperative hypothalamic status was better in the TCA group than in the EEA group (p = 0.016). Postoperative CSF leaks and nasal complication rates occurred more frequently in the EEA group (12.0% vs 0.5%, and 9.6% vs 0.5%; both p < 0.001). For Q-CPs, EEA was associated with an increased gross-total resection rate (97.4% vs 85.7%, p = 0.017), decreased recurrence rate (2.6% vs 12.2%, p = 0.001), and lower new hypopituitarism rate (28.9% vs 57.1%, p = 0.008). The recurrence-free survival in patients with Q-CPs was also significantly different between surgical groups (log-rank test, p = 0.037). The EEA required longer surgical time for T-CPs (p = 0.01).

CONCLUSIONS CPs could be effectively treated by radical surgery with favorable results. Both TCA and EEA have their advantages and limitations when used to manage different types of tumors. Individualized surgical strategies based on tumor growth patterns are mandatory to achieve optimal outcomes.

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Neurosurgical management of petrous bone lesions: classification system and selection of surgical approaches

Acta Neurochirurgica (2021) 163:2895–2907

Surgery of petrous bone lesions (PBLs) is challenging for neurosurgeons. Selection of the surgical approach is an important key for success. In this study, the authors present an anatomical classification for PBLs that has been used by our group for over the past 26 years. The objective of this study is to investigate the benefits and applicability of this classification.

Methods Between 1994 and 2019, 117 patients treated for PBLs were retrospectively reviewed. Using the V3 and arcuate eminence as reference points, the petrous bone is segmented into 3 parts: petrous apex, rhomboid, and posterior. The pathological diagnoses, selection of the operative approach, and the extent of resection (EOR) were analyzed and correlated using this classification.

Results This series included 22 facial nerve schwannomas (18.8%), 22 cholesterol granulomas (18.8%), 39 chordomas/ chondrosarcomas (33.3%), 6 trigeminal schwannomas (5.1%), 13 epidermoids/dermoids (11.1%), and 15 other pathologies (12.8%). PBLs were most often involved with the petrous apex and rhomboid areas (46.2%). The extradural subtemporal approach (ESTA) was most frequently used (57.3%). Gross total resection was achieved in 58.4%. Symptomatic improvement occurred in 92 patients (78.6%). Our results demonstrated a correlation between this classification with each type of pathology (p < .001), selection of surgical approaches (p < 0.001), and EOR (p = 0.008). Chordoma/chondrosarcoma, redo operations, and lesions located medially were less likely to have total resection. Temporary complications occurred in 8 cases (6.8%), persistent morbidity in 5 cases (4.3%), and mortality in 1 case.

Conclusion In this study, we proposed a simple classification of PBLs. Using landmarks on the superior petrosal surface, the petrous bone is divided into 3 parts, apex, rhomboid, and posterior. Our results demonstrated that chordoma/chondrosarcoma, redo operations, and lesions involving the tip of the petrous apex or far medial locations were more difficult to achieve total resection. This classification could help surgeons understand surgical anatomy framework, predict possible structures at risk, and select the most appropriate approach for each patient.

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Petrous bone lesions: surgical implementation and outcomes of extradural subtemporal approach

Acta Neurochirurgica (2021) 163:2881–2894

Petrous bone lesions (PBLs) are rare with few reports in the neurosurgical literature. In this study, the authors describe our current technique of extradural subtemporal approach (ESTA). The objective of this study was to evaluate the role and efficacy of ESTA for treatment of the PBLs. To our knowledge, this is the largest reported clinical series of using an ESTA-treated PBLs in which the clinical outcomes were evaluated.

Methods Between 1994 and 2019, 67 patients with PBLs treated by ESTA were retrospectively reviewed. Extent of resection, neurological outcomes, recurrence rate, and surgical complications were evaluated and compared with previous studies. The indications, advantages, limitations, and outcomes of ESTA were analyzed according to pathology.

Results This series included 7 facial nerve schwannomas (10.4%), 16 cholesterol granulomas (23.9%), 16 chordomas (23.9%), 6 chondrosarcomas (9%), 5 trigeminal schwannomas (7.5%), 9 epidermoids/dermoids (13.4%), and 8 other pathologies (11.9%). The most common location of PBLs operated with ESTA was at the petrous apex and rhomboid areas (68.7%). Gross total resection was achieved in 35 (55.6%). Symptomatic improvement occurred in 56 patients (83.6%). Complications occurred in 7 (10.4%) of cases including one mortality. Nine patients (17%) had recurrence within the mean follow-up 71 months. Compared to previous literature, our results demonstrated comparable outcomes but with higher rates of hearing and facial nerve preservation as well as minimal morbidity. From our results, ESTA is an effective therapeutic option for lesions located at the rhomboid and petrous apex, particularly when patients presented with intact facial and hearing function.

Conclusion Our series demonstrated that ESTA provided satisfactory outcomes with excellent benefits of hearing and facial function preservation for patients with petrous bone lesions. ESTA should be considered as a safe and effective therapeutic option for selected patients with PBLs.

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Impact of vestibular nerve preservation on facial and hearing outcomes in small vestibular schwannoma surgery

Acta Neurochirurgica (2021) 163:2219–2224

Management of small vestibular schwannomas (VSs) remains controversial. When surgery is chosen, the preservation of facial and cochlear nerve function is a priority. In this report, we introduce and evaluate a technique to anatomically preserve the vestibular nerves to minimize manipulation and preserve the function of the facial and cochlear nerves.

Methods The vestibular nerve preservation technique was prospectively applied to resect small VS tumors in patients with serviceable preoperative hearing (American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) class A or B). Clinical and radiological data were recorded and analyzed.

Results Ten patients met the inclusion criteria. The mean (SD) age was 40.4 (12.5) years. Follow-up ranged from 6 weeks to 2 years. The maximum tumor diameter parallel to the internal auditory canal ranged from 10 to 20 mm (mean, 14.9 (3.1) mm). There were three Koos grade 3 and seven Koos grade 2 tumors. Gross total resection was achieved in all cases. Both the facial and cochlear nerves were anatomically preserved in all cases. Postoperatively, 7 patients (70%) remained in the AAO-HNS class A or B hearing category. None of the patients had new vestibular symptoms, and all had House–Brackmann grade 1 facial function. Nervus intermedius dysfunction was observed in 1 patient preoperatively, which worsened postoperatively. Two patients had new nervus intermedius symptoms postoperatively.

Conclusion Improvement of facial nerve and hearing outcomes is feasible through the intentional preservation of the vestibular nerves in the resection of small VSs. Longer follow-up is required to rule out tumor recurrence.

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Large and small vestibular schwannomas: same, yet different tumors

Acta Neurochirurgica (2021) 163:2199–2207

Vestibular schwannomas (VS) present at variable size with heterogeneous symptomatology. Modern treatment paradigms for large VS include gross total resection, subtotal resection (STR) in combination with observation, and/or radiation to achieve optimal function preservation, whereas treatment is felt to be both easier and safer for small VS. The objective is to better characterize the presentation and surgical outcomes of large and small VS.

Methods We collected data of patients who had surgically treated VS with a posterior fossa diameter of 4.0 cm or larger (large tumor group, LTG) and smaller than 1.0 cm in cisternal diameter (small tumor group, STG). Statistical significance was defined as p < 0.05.

Results LTG included 48 patients (average tumor size: 44.9 mm) and STG 38 (7.9 mm). Patients in STG presented more frequently with tinnitus and sudden hearing loss. Patients in LTG underwent more STR than STG (50.0% vs. 2.6%, p < 0.0001). LTG had more complications (31.3% vs. 13.2%, p = 0.049). Postoperative facial nerve function in STG was significantly better than LTG. STG had better hearing preoperatively (p < 0.0001) and postoperatively than LTG (p = 0.0002). Postoperative headache was more common in STG (13.2% vs. 2.1%, p = 0.045). The rate of recurrence/progression needing treatment was not statistically different between the groups (12.5% in LTG vs. 7.9% in STG, p = 0.49). Those patients who required periprocedural cerebrospinal fluid diversion had higher risk of infection (20.8% vs 4.8%, p = 0.022).

Conclusion Large and small VS present differently. LTG showed more unsatisfactory outcomes in facial nerve function and postoperative hearing despite maximal efforts undertaken toward function-preservation strategy; however, similar tumor control was achieved.

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The orbitopterygoid corridor as a deep keyhole for endoscopic access to the paranasal sinuses and clivus

J Neurosurg 134:1480–1489, 2021

The anteromedial triangle (AMT) is the triangle formed by the ophthalmic (V1) and maxillary (V2) nerves. Opening of this bony space offers a limited access to the sphenoid sinus (SphS). This study aims to demonstrate the utility of the orbitopterygopalatine corridor (OPC), obtained by enlarging the AMT and transposing the contents of the pterygopalatine fossa (PPF) and V2, as an entrance to the SphS, maxillary sinus (MaxS), and nasal cavity.

METHODS Five formalin-injected cadaveric specimens were used for this study (10 approaches). A classic pterional approach was performed. An OPC was created through the inferior orbital fissure, between the orbit and the PPF, by transposing the PPF inferiorly. The extent of the OPC was measured using neuronavigation and manual measurements. Two illustrative cases using the OPC to access skull base tumors are presented in the body of the article.

RESULTS Via the OPC, the SphS, MaxS, ethmoid sinus (EthS), and nasal cavity could be accessed. The use of endoscopic assistance through the OPC achieved better visualization of the EthS, SphS, MaxS, clivus, and nasal cavity. A significant gain in the area of exposure could be achieved using the OPC compared to the AMT (22.4 mm2 vs 504.1 mm2).

CONCLUSIONS Opening of the AMT and transposition of V2 and the contents of the PPF creates the OPC, a potentially useful deep keyhole to access the paranasal sinuses and clival region through a middle fossa approach. It is a valuable alternative approach to reach deep-seated skull base lesions infiltrating the cavernous sinus and middle cranial fossa and extending into the paranasal sinus.

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Hyperostosing sphenoid wing meningiomas: surgical outcomes and strategy for bone resection and multidisciplinary orbital reconstruction

J Neurosurg 134:711–720, 2021

Hyperostosing sphenoid wing meningiomas cause bony hyperostosis that may extend into the orbit, resulting in proptosis, restriction of extraocular movements, and/or compressive optic neuropathy. The extent of bony removal necessary and the optimal reconstruction strategy to prevent enophthalmos is debated. Herein, the authors present their surgical outcomes and reconstruction results.

METHODS This is a retrospective review of 54 consecutive patients undergoing resection of sphenoid wing meningiomas associated with bony hyperostosis. The majority of cases were operated on by the senior author. Extent of tumor resection, volumetric bone resection, radiographic exophthalmos index, complications, and recurrence were analyzed.

RESULTS The median age of the cohort was 52.1 years, with women comprising 83% of patients. Proptosis was a presenting symptom in 74%, and 52% had decreased visual acuity. The WHO grade was I (85%) or II (15%). The median follow-up was 2.6 years. On volumetric analysis, a median 86% of hyperostotic bone was resected. Gross-total resection of the intracranial tumor was achieved in 43% and the orbital tumor in 27%, and of all intracranial and orbital components in 20%. Orbital reconstruction was performed in 96% of patients. Postoperative vision was stable or improved in 98% of patients and diplopia improved in 89%. Postoperative complications occurred in 44% of patients, and 26% of patients underwent additional surgery for complication management. The most frequent complications were medical complications and extraocular movement deficits. The median preoperative exophthalmos index was 1.26, which improved to 1.12 immediately postoperatively and to 1.09 at the 6-month follow-up (p < 0.001). Postoperatively, 18 patients (33%) underwent adjuvant radiotherapy after subtotal resection. Tumors recurred/progressed in 12 patients (22%).

CONCLUSIONS Resection of hyperostosing sphenoid wing meningiomas, particularly achieving gross-total resection of hyperostotic bone with a good aesthetic result, is challenging and associated with notable medical and ocular morbidity. Recurrence rates in this series are higher than previously reported. Nevertheless, the authors were able to attain improvement in proptosis and visual symptoms in the majority of patients by using a multidisciplinary approach.

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Trigeminal schwannoma: a single-center experience with 43 cases and review of literature

British Journal of Neurosurgery 2021, 35:1, 49-56

Trigeminal schwannomas (TS) are rare, when compared to vestibular schwannomas. The present study aims to analyze the clinical characteristics and surgical strategies of TS via the retrospective analysis of the clinical data of 43 patients.

Methods: The clinical information of 43 patients diagnosed with TS, who were surgically treated from January 2008 to January 2018, was retrospectively analyzed. Then, the selection of approaches and surgical strategies were discussed.

Results: During the last 10 years, 43 patients with TS received surgical treatment at Xuan Wu Hospital of Capital Medical University. Facial numbness and hypoesthesia were the most common symptoms, which developed in 29 cases (67.4%). Typical trigeminal neuralgia was complained by four patients (9.3%), while trigeminal motor impairment developed in nine cases (20.9%). The tumor was totally removed in 39 patients (90.7%), near-totally removed in three patients (7.0%), and partially removed in one patient (2.3%) due to intraoperative internal carotid artery (ICA) injury. The abducens was intraoperatively damaged in two patients (4.7%). After the operation, all four patients with trigeminal neuralgia achieved total recovery, but the facial numbness still continued in 24 patients (82.8%). At a median of 45.3 ± 25.5 (6–84) months of follow up, a tumor recurred in only one patient, and this patient received a second operation.

Conclusion: It can be concluded that total removal via the proper approach can be the best treatment for TS with a low complication rate. However, preoperative symptoms, such as facial numbness and trigeminal motor impairment that seldom improved though normal fibers, were carefully recognized and preserved during the operation.

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Access to Meckel’s cave for biopsies of indeterminate lesions

Neurosurgical Review (2021) 44:249–259

Accessing Meckel’s cave (MC) is surgically challenging. Open approaches are complex and often correlated with high morbidity. Endoscopic approaches emerged in the last decade as feasible alternatives to open approaches, especially for sampling indeterminate lesions.

This article first analyses available routes to approach Meckel’s cave and presents furthermore an illustrative case. We conducted a systematic review and reported according to the guidelines for preferred reporting items for systematic reviews and meta-analyses (PRISMA). Various surgical approaches identified through the search are evaluated and discussed in detail. Additionally, we report on a case of woman with a lesion in MC, which was accessed through an endoscopic transpterygoid approach subsequently diagnosed as a diffuse large B cell lymphoma. Our search delivered 75 articles that included case reports (n = 21), cadaveric studies (n = 32), clinical articles (n = 16), review of the literatures (n = 3), as well as technical notes (n = 2) and a radiological manuscript (n = 1).

Open routes included lateral approaches with many variations, mainly intra- and extradural pterional approaches and anterior petrosal, as well as a retrosigmoid intradural suprameatal and a lateral transorbital approach.

Endoscopically, MC was reached via approaches that included transpterygoid, transorbital or infraorbital fissure routes.

Percutaneous approaches, e.g. through the foramen ovale, were also described. Multiple surgical approaches to MC are currently available.

Their different characteristics as well as individual patient factors, such as clinical history and the localization of the disease, have to be considered when choosing a surgical corridor.

Studies included in this review highlight the endonasal endoscopic transpterygoidal technique as an excellent corridor for biopsies in the ventral MC.

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Surgery for diaphragma sellae meningioma: how I do it

Acta Neurochirurgica (2021) 163:97–100

Surgery for diaphragma sellae meningiomas (DSM) remains challenging due to the intimate neurovascular relationships of the tumor. Excision of DSM along with a decompression of the optic apparatus requires a good knowledge of the skull base anatomy and a precise preoperative evaluation of the tumor extensions.

Method We describe the key steps of transcranial approach for DSM with a video illustration. The surgical anatomy is described along with the advantages and limitations of this approach.

Conclusions The transcranial approach allows a safe tumor excision with an early and adequate control of the neurovascular structures, while minimizing postoperative CSF rhinorrhea.

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Eyebrow supraorbital keyhole craniotomy for olfactory groove meningiomas with endoscope assistance

Acta Neurochirurgica (2021) 163:101–112

Olfactory groove meningiomas (OGMs) are commonly treated with open craniotomy. Endonasal approaches have also been described. Objective To present clinical and radiographic outcomes for the minimally invasive eyebrow incision supraorbital keyhole approach with endoscopic assistance for OGMs.

Methods We performed a retrospective single-center cohort study and a systematic literature review.

Results Fifteen patients were identified, all with Grade I meningiomas. Radiographic gross total resection of enhancing tumor was achieved in all patients. Mean frontal lobe fluid-attenuated inversion recovery volume decreased from 11.1 ± 18.3 cm3 preoperatively to 9.9 ± 11.4 cm3 immediately postoperatively, and there was minimal new restricted diffusion (3.2 ± 2.2 cm3; max 7.5 cm3). Median length of stay was 3 days (range 2–8). Vision was improved in 4 (80%) and stable in 1 (20%) of 5 patients with a preoperative deficit. New postoperative anosmia occurred in 3 (23%) of 13 patients with any preoperative olfaction. All patients were satisfied with their cosmetic result at 3 months. After a median follow-up of 32.2 months, there were 2 (13.3%) asymptomatic radiographic recurrences, 1 treated with radiosurgery and the other with endoscopic endonasal approach (EEA). No patients required further craniotomy. Systematic review revealed the present series to be the largest to date reporting disaggregated outcomes for the eyebrow approach to OGM.

Conclusion The eyebrow incision supraorbital keyhole craniotomy with endoscopic assistance is a safe and effective approach to OGM with tumor control rates similar to more invasive open approaches and better than the endonasal approach.Rates of frontal lobe injury, CSF leak and anosmia are comparatively low.

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Surgical management for large vestibular schwannomas: a systematic review, meta-analysis, and consensus statement on behalf of the EANS skull base section

Acta Neurochir (2020) 162:2595–2617

The optimal management of large vestibular schwannomas continues to be debated. We constituted a task force comprising the members of the EANS skull base committee along with international experts to derive recommendations for the management of this problem from a European perspective.

Material and methods A systematic review of MEDLINE database, in compliance with the PRISMA guidelines, was performed. A subgroup analysis screening all surgical series published within the last 20 years (January 2000 to March 2020) was performed. Weighted summary rates for tumor resection, oncological control, and facial nerve preservation were determined using metaanalysis models. This data along with contemporary practice patterns were discussed within the task force to generate consensual recommendations regarding preoperative evaluations, optimal surgical strategy, and follow-up management.

Results Tumor classification grades should be systematically used in the perioperative management of patients, with large vestibular schwannomas (VS) defined as > 30 mm in the largest extrameatal diameter. Grading scales for pre- and postoperative hearing (AAO-HNS or GR) and facial nerve function (HB) are to be used for reporting functional outcome. There is a lack of consensus to support the superiority of any surgical strategy with respect to extent of resection and use of adjuvant radiosurgery. Intraoperative neuromonitoring needs to be routinely used to preserve neural function. Recommendations for postoperative clinico-radiological evaluations have been elucidated based on the surgical strategy employed.

Conclusion The main goal of management of large vestibular schwannomas should focus on maintaining/improving quality of life (QoL), making every attempt at facial/cochlear nerve functional preservation while ensuring optimal oncological control, thereby allowing to meet patient expectations. Despite the fact that this analysis yielded only a few Class B evidences and mostly expert opinions, it will guide practitioners to manage these patients and form the basis for future clinical trials.

Keywords

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Surgical treatment of falcotentorial meningiomas

J Neurosurg 133:630–641, 2020

Meningiomas at the falcotentorial junction represent a rare subgroup of complex meningiomas. Debate remains regarding the appropriate treatment strategy for and optimal surgical approach to these tumors, and surgical outcomes have not been well described in the literature. The authors reviewed their single-institution experience in the management, approach selection, and outcomes for patients with falcotentorial meningiomas.

METHODS From the medical records, the authors identified all patients with falcotentorial meningiomas treated with resection at the Barrow Neurological Institute between January 2007 and October 2017. Perioperative clinical, surgical, and radiographic data were retrospectively collected. For patients who underwent the supracerebellar infratentorial approach, the tentorial angle was defined as the angle between the line joining the nasion with the tuberculum sellae and the tentorium in the midsagittal plane.

RESULTS Falcotentorial meningiomas occurred in 0.97% (14/1441) of the patients with meningiomas. Most of the patients (13/14) were female, and the mean patient age was 59.8 ± 11.3 years. Of 17 total surgeries (20 procedures), 11 were single-stage primary surgeries, 3 were two-stage primary surgeries (6 procedures), 2 were reoperations for recurrence, and 1 was a reoperation after surgery had been aborted because of brain edema. Hydrocephalus was present in 5 of 17 cases, 4 of which required additional treatment. Various approaches were used, including the supracerebellar infratentorial (4/17), occipital transtentorial/transfalcine (4/17), anterior interhemispheric transsplenial (3/17), parietal transventricular (1/17), torcular (2/17), and staged supracerebellar infratentorial and occipital transtentorial/transfalcine (3/17) approaches. Of the 17 surgeries, 9 resulted in Simpson grade IV resection, and 3, 1, and 4 surgeries resulted in Simpson grades III, II, and I resection, respectively. The tentorial angle in cases with Simpson grade I resection was significantly smaller than in those with an unfavorable resection grade (43.3° ± 4.67° vs 54.0° ± 3.67°, p = 0.04). Complications occurred in 10 of 22 approaches (17 surgeries) and included visual field defects (6 cases, 2 permanent and 4 transient), hemiparesis (2 cases), hemidysesthesia (1 case), and cerebellar hematoma (1 case).

CONCLUSIONS Falcotentorial meningiomas are challenging lesions. A steep tentorial angle is an unfavorable preoperative radiographic factor for achieving maximal resection with the supracerebellar infratentorial approach. Collectively, the study findings show that versatility is required to treat patients with falcotentorial meningiomas and that treatment goals and surgical approach must be individualized to obtain optimal surgical results.

https://thejns.org/doi/abs/10.3171/2019.4.JNS19208

KEYWORDS falcotentorial; meningioma; surgery; oncology

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Endoscopic transorbital and endonasal approach for trigeminal schwannomas

J Neurosurg 133:467–476, 2020

Trigeminal schwannomas are rare neoplasms with an incidence of less than 1% that require a comprehensive surgical strategy. These tumors can occur anywhere along the path of the trigeminal nerve, capable of extending intradurally into the middle and posterior fossae, and extracranially into the orbital, pterygopalatine, and infratemporal fossa. Recent advancements in endoscopic surgery have suggested a more minimally invasive and direct route for tumors in and around Meckel’s cave, including the endoscopic endonasal approach (EEA) and endoscopic transorbital superior eyelid approach (ETOA). The authors assess the feasibility and outcomes of EEA and ETOA for trigeminal schwannomas.

METHODS A retrospective multicenter analysis was performed on 25 patients who underwent endoscopic surgical treatment for trigeminal schwannomas between September 2011 and February 2019. Thirteen patients (52%) underwent EEA and 12 (48%) had ETOA, one of whom underwent a combined approach with retrosigmoid craniotomy. The extent of resection, clinical outcome, and surgical morbidity were analyzed to evaluate the feasibility and selection of surgical approach between EEA and ETOA based on predominant location of trigeminal schwannomas.

RESULTS According to predominant tumor location, 9 patients (36%) had middle fossa tumors (Samii type A), 8 patients (32%) had dumbbell-shaped tumors located in the middle and posterior cranial fossae (Samii type C), and another 8 patients (32%) had extracranial tumors (Samii type D). Gross-total resection (GTR, n = 12) and near-total resection (NTR, n = 7) were achieved in 19 patients (76%). The GTR/NTR rates were 81.8% for ETOA and 69.2% for EEA. The GTR/NTR rates of ETOA and EEA according to the classifications were 100% and 50% for tumors confined to the middle cranial fossa, 75% and 33% for dumbbell-shaped tumors located in the middle and posterior cranial fossae, and 50% and 100% for extracranial tumors. There were no postoperative CSF leaks. The most common preoperative symptom was trigeminal sensory dysfunction, which improved in 15 of 21 patients (71.4%). Three patients experienced new postoperative complications such as vasospasm (n = 1), wound infection (n = 1), and medial gaze palsy (n = 1).

CONCLUSIONS ETOA provides adequate access and resectability for trigeminal schwannomas limited in the middle fossa or dumbbell-shaped tumors located in the middle and posterior fossae, as does EEA for extracranial tumors. Tumors predominantly involving the posterior fossa still remain a challenge in endoscopic surgery.

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Surgical treatment of pontine cavernous malformations via subtemporal transtentorial and intradural anterior transpetrosal approaches

Neurosurgical Review (2020) 43:1179–1189

The aim of this study was to report our surgical experience on resection of the pontine cavernous malformations (CMs) via subtemporal transtentorial approach (STTA) and intradural anterior transpetrosal approach (ATPA).

Clinical data were retrospectively reviewed in 61 patients with pontine CMs that were surgically treated by the STTA and the intradural ATPA. The surgical procedures, complications, and outcomes were analyzed.

The study consists of 61 patients with a total of 61 pontine CMs. Other than 4 lesions located medially in the pons, all CMs were in the lateral pons with a left or right lateral epicenter (the left/right ratio was 22/35). Totally, 11 patients (18.0%) with lesions located in the upper pons were treated by the STTA, and 50 patients (82.0%) with lesions involving the lower pons were treated by the intradural ATPA. Postoperatively, the complete resection was achieved in 58 patients (95.1%) and incomplete resection in 3 patients (4.9%). Twenty-seven patients (44.3%) suffered from a new or worsened neurological deficit in the immediate postoperative period, and 8 patients (13.1%) encountered a non-neural complication, including rebleeding, cerebrospinal fluid leak, intracranial infection, and pulmonary infection, and 3 patients had contusion of temporal lobe. With a mean follow-up of 54.2 months, the patients’ neurological condition had improved in 43 cases (71.6%), not changed in 10 cases (16.7%), and worsened in 7 cases (11.7%), respectively. The Karnofsky Performance Scale (KPS) score evaluated at the last time for per patient was significantly better than their baseline status (t = 6.677, p < 0.001). However, 21 patients (35.0%) suffered from a new or worsened persistent postoperative deficit.

The lateral and anterolateral pons can be exposed well by the subtemporal transtentorial and intradural anterior transpetrosal approaches. Lesions of CMs located in the lateral pons, including ventrolateral and dorsolateral pons, could be totally removed by these two lateral approaches with an acceptable surgical morbidity.

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Clinical features and operative technique of transinfundibular craniopharyngioma

J Neurosurg 133:119–128, 2020

Transinfundibular craniopharyngioma (TC) is one of the 4 subtypes of suprasellar craniopharyngioma. In this study, the authors analyzed the clinical features of and operative technique for TC.

METHODS A total of 95 consecutive cases of suprasellar craniopharyngioma that had been resected via the endoscopic expanded endonasal approach were retrospectively reviewed. Patients were divided into 2 groups: 34 in the TC group and 61 in the nontransinfundibular craniopharyngioma (NC) group. Clinical and radiographic features, intraoperative findings, histopathological and genetic findings, and surgical outcomes were analyzed and compared between groups.

RESULTS Compared with NC, TC was mostly seen in adult patients (97.1%); it was rare in children (2.9%). Clinical presentations tended toward headache, hydrocephalus, and diabetes insipidus. The relatively smaller volume, midline location (consistent with the stalk position), unidentifiable stalk, no shift of the third ventricle, and greater likelihood to involve the third ventricle and cause hydrocephalus were the characteristic features of TC in the preoperative MRI study. According to the degree of vertical extension of the tumor, the 34 TCs could be classified into 3 subtypes: type 1, entity was limited to stalk (n = 2, 5.9%); type 2, tumor extended up to the third ventricle (type 2a) or down to the subdiaphragmatic cavity (type 2b) (n = 23, 67.6%); and type 3, tumor extended in both directions (n = 9, 26.5%). For TC resection, the chiasm–pituitary corridor, lamina terminalis corridor, and pituitary corridor could be used separately or jointly. Most of the TCs originated from the infundibulum–tuber cinereum, grew within and along the long axis of the infundibulum, and the pituitary stalk was not usually preserved in TCs (20.6%), whereas the rate of preservation was higher (80.3%) in NCs. Bilateral hypothalamic injury was found in nearly all TCs if radical resection was performed, whereas the relationship between NCs and hypothalamus was either compression (32.8%) or unilateral invasion (67.2%). Meanwhile, the postoperative endocrine and neuropsychological function outcomes in patients with TC were worse than in patients with NC. The genetic analysis with whole-exome sequencing studies showed no differential mutations of CTNNB1 (b-catenin) and BRAF (V600E) between TC and NC subtypes, but there was a difference between adamantinomatous craniopharyngioma and papillary craniopharyngioma.

CONCLUSIONS TC is a special subtype of suprasellar craniopharyngioma, which is remarkably different from NC. Identification of this type of tumor preoperatively is essential for the planning of appropriate surgical approach and degree of excision.

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A clinical study of ocular motor nerve functions after petroclival meningioma resection

Acta Neurochirurgica (2020) 162:1249–1257

Ocular motor dysfunction is one of the most common postoperative complications of petroclival meningioma. However, its incidence, recovery rate, and independent risk factors remain poorly explored.

Methods: A prospective analysis of 31 petroclival meningiomas was performed. Operative approaches were selected by utilizing a new 6-region classification of petroclival meningiomas we proposed. Two scores were used to evaluate the functions of the oculomotor and abducens nerves. Pearson correlation analysis and binary logistic regression analysis were used to identify independent risk factors for intraoperative oculomotor and abducens nerve injury.

Results: Postoperative new-onset dysfunctions in the pupillary light reflex and eye/eyelid movements as well as abducens paralysis were detected in eight (25.8%), ten (32.3%) and twelve (38.7%) cases, respectively. Their corresponding recovery rates after 6 months of follow-up were 75% (6/8), 80% (8/10), and 83.3% (10/12), respectively, and their mean times to start recovery were 4.03, 2.43, and 2.5 months, respectively. Tumor invasion into the suprasellar region/sphenoid sinus was the only risk factor for dysfunctions in both the pupillary light reflex (p = 0.001) and eye/ eyelid movements (p = 0.002). Intraoperative utilization of the infratrigeminal interspace was the only risk factor for dysfunction in eyeball abduction movement (p = 0.004).

Conclusions: Dysfunctions of the oculomotor and abducens nerves recovered within 6 months postoperatively. Tumor extension into the suprasellar region/sphenoid sinus was the only risk factor for oculomotor nerve paralysis. Eye/eyelid movements were more sensitive than the pupillary light reflex in reflecting nerve dysfunctions. Intraoperative utilization of the infratrigeminal interspace was the only risk factor for abducens nerve paralysis.

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