Outcomes of decompressive surgery for cavernous sinus meningiomas: long-term follow-up in 50 patients

Multiple approaches to a spheno-orbital and deep face meningioma: how I do it

BACKGROUND

The integration of multiple approaches is sometimes needed for the safe resection of complex multicompartment skull base tumors.

METHOD

We present the case of a spheno-orbital and deep face meningioma that required a staged resection strategy using transnasal, transoral, transfacial, and transcranial approaches for airway protection and maximal safe tumor removal.

CONCLUSION

Limitations in individual skull base approaches for complex tumors can be anticipated and overcome by combining approaches.

Lateral Transorbital Endoscope-Assisted Approach to the Cavernous Sinus

BACKGROUND AND OBJECTIVES

Surgical access to the cavernous sinus (CS) poses a unique challenge to the neurosurgeon given the concentration of delicate structures in the confines of a very small anatomic space. The lateral transorbital approach (LTOA) is a minimally invasive, keyhole approach that can provide direct access to the lateral CS.

METHODS

A retrospective review of CS lesions treated by a LTOA at a single institution was performed between 2020 and 2023. Patient indications, surgical outcomes, and complications are described.

RESULTS

Six patients underwent a LTOA for a variety of pathologies including a dermoid cyst, schwannoma, prolactinoma, craniopharyngioma, and solitary fibrous tumor. The goals of surgery (ie, drainage of cyst, debulking, and pathological diagnosis) were achieved in all cases. The mean extent of resection was 64.6% (±34%). Half of the patients with preoperative cranial neuropathies (n = 4) improved postoperatively. There were no new permanent cranial neuropathies. One patient had a vascular injury repaired endovascularly with no neurological deficits.

CONCLUSION

The LTOA provides a minimal access corridor to the lateral CS. Careful case selection and reasonable goals of surgery are critical to successful outcome.

Bibliometric analysis of the top 100 cited articles on stereotactic radiosurgery of intracranial meningiomas

BACKGROUND

Sterotactic radiosurgery is becoming an integral modality in the management of intracranial meningiomas, both as the primary treatment or as adjuvant therapy. This study analyzes the scholarly impact of the top 100 cited articles on the stereotactic radiosurgical management of intracranial meningiomas.

METHODS

A ranked list of the 100 most-cited articles was generated using the Scopus database by searching the keywords 'intracranial meningioma' and 'stereotactic radiosurgery'. All articles were then evaluated on multiple criteria regarding both the publication of the articles (year of publication, journal, country of origin, and authors) as well as their methods and foci (type of study, location of studied meningiomas, and type of radiosurgical modality). Quantitaitve and qualitative analyses were then performed from the collected data.

RESULTS

The most frequently cited articles on stereotactic radiosurgical management of intracranial meningiomas were published between 1990 and 2016. The average citation-per-year across all papers in the list was 6.1. The most studied anatomic area of intracranial meningiomas was the skull base, with the cavernous sinus being the most well-studied specific site. The most utilized stereotactic radiosurgical modality was Gamma Knife radiosurgery. The country with the highest number of publications was the United States. Twenty-six percent of the articles were published in the journal Neurosurgery; Lunsford, Kondziolka, Flickinger, Sheehan, and Pollock were respectively the most frequent listed authors among this list. The most active academic institute publishing on this topic was the University of Pittsburgh Medical Center.

CONCLUSION

Stereotactic radiosurgery is an integral modality in the management of intracranial meningiomas. This bibliometric analysis sheds the light on the ways in which intracranial meningiomas have been studied in the past two decades in order to identify trends among neurosurgeons and radiation oncologists and to reveal areas of rising and declining focus.

Endoscopic Extended Transsphenoidal Surgery Aiming for Radical Resection of Skull Base Tumors Involving Cavernous Sinus: Assessment of Resectability and Risks of Complications

BACKGROUND AND OBJECTIVES

Surgical resection of tumors invading the cavernous sinus (CS) still shows therapeutic challenges. For "nonadenomatous" skull base tumors invading in CS, there were only a few reports showing the outcomes of radical resection. Therefore, the outcomes of endoscopic transsphenoidal surgery (ETS) aiming for radical resection thus remain largely unknown regarding resectability and functional results of the cranial nerves.

METHODS

We performed ETS aiming for radical resection in 35 skull base tumors involving CS (17 chondrosarcomas, 12 chordomas, 3 meningiomas, and 3 trigeminal schwannomas; median follow-up 36.5 months ranging from 12 to 91 months). Gross total resection (GTR) is attempted in all the cases for real-time findings from electrophysiological monitoring of the cranial nerves. When the tumor was strongly adherent to the cranial nerves or internal carotid artery, maximum volume reduction of the tumor was attempted.

RESULTS

GTR was achieved in 28 patients (80.0%), subtotal resection in 3 (8.6%), and partial resection in 4 (11.4%). One patient experienced internal carotid artery injury during surgery. After ETS, 15 patients showed symptom improvement (51.7% in all 29 patients with preoperative cranial nerve symptoms, CNS). Four (11.4%) transiently developed abducens nerve palsy, and one required repair surgery for cerebrospinal leakage. In univariate analyses, extension to the lateral compartment of CS ( P = .04) was significantly associated with reduced achievement of GTR. Previous transcranial surgery was associated with reduced possibility of improvement and worsening in CNS. Eleven patients underwent stereotactic radiosurgery, at a median of 12 months after ETS. 32 patients (91.4%) did not show recurrence at the final follow-up.

CONCLUSION

ETS can achieve sufficient surgical resection in most of the patients, with acceptable neurological complications. For patients with CNS, ETS may offer the opportunity for improving CNS. We should also always prioritize avoidance of critical situations by preventing internal carotid artery injury.

Subtemporal approach for cavernous sinus meningiomas - Simple and effective

Background

Over the past few decades, there has been a paradigm shift in treatment strategy for cavernous sinus meningiomas (CSMs). Preserving neurological function and cranial nerve (CN) decompression have become the primary goal of cases eligible for surgical treatment. Extensive skull base dissection and drilling can be avoided by approaching these lesions through a subtemporal route.

Methods

We describe the subtemporal approach in a step-by-step fashion illustrating its advantages and pitfalls through and illustrative case.

Results

The subtemporal approach to CSMs is a valuable alternative for CN decompression and maximal safe resection. We describe the technique in comparison to classical skull base approaches. Although rare, recurrence after adjuvant maximal radiation is possible leaving reoperation as the only treatment option.

Conclusion

The subtemporal approach offers a less invasive alternative for initial and redo CN decompression and successful symptom control in patients suffering from CSM.

Skull Base Meningiomas

Skull base meningiomas are among the most challenging meningiomas to treat clinically due to their deep location, involvement or encasement of adjacent essential neurovascular structures (such as key arteries, cranial nerves, veins, and venous sinuses), and their often-large size prior to diagnosis. Although multimodal treatment strategies continue to evolve with advances in stereotactic and fractionated radiotherapy, surgical resection remains the mainstay of treatment for these tumors. Resection of these tumors however is challenging from a technical standpoint, and requires expertise in several skull-base surgical approaches that rely on adequate bony removal, minimization of brain retraction, and respect for nearby neurovascular structures. These skull base meningiomas originate from a variety of different structures including, but are not limited to: the clinoid processes, tuberculum sellae, dorsum sellae, sphenoid wing, petrous/petroclival area, falcotentorial region, cerebellopontine angle, and foramen magnum. In this chapter, we will cover the common anatomical areas in the skull base from which these tumors arise, and the specific or optimal surgical approaches and other treatment modalities for meningiomas in these such locations.

Single session versus multisession stereotactic radiosurgery for the management of intracranial meningiomas: a systematic review and meta-analysis

PURPOSE

To compare the efficacy, outcomes, and complications of single session (SS-SRS) and multisession (MS-SRS) stereotactic radiosurgery in the treatment of intracranial meningiomas.

METHODS

Relevant articles were retrieved from PubMed, Scopus, Web of Science, and Cochrane. A systematic review and meta-analysis of treatment protocols and outcomes were conducted. After the selection process, 20 articles describing 1483 cases were included.

RESULTS

A total of 1303 patients who underwent SS-SRS and 180 patients who underwent MS-SRS for the management of their intracranial meningioma were reported in the included studies. SS-SRS and MS-SRS had comparable one-year (SS-SRS: 98% vs. MS-SRS: 100%, p > 0.99) and five-year (SS-SRS: 94% vs. MS-SRS: 93%, p = 0.71) tumor control rates. The groups also had comparable tumor volume reduction/tumor regression rates (SS-SRS: 44% vs. MS-SRS: 25%, p = 0.25), tumor volume stability rates (SS-SRS: 51% vs. MS-SRS: 75%, p = 0.12), and tumor progression rates (SS-SRS: 4% vs. MS-SRS: 4%, p = 0.89). SS-SRS and MS-SRS yielded similar complication rates (10.4% vs. 11.4%, p = 0.68) and comparable functional improvement rates (MS-SRS: 44% vs. SS-SRS: 36%, p = 0.57). However, MS-SRS was used for significantly larger tumor volumes (MS-SRS: 23.8 cm³ vs. SS-SRS: 6.1 cm³, p = 0.02).

CONCLUSION

SS-SRS and MS-SRS resulted in comparable tumor control, tumor volumetric change, and functional outcomes despite significant biases in selecting patients for SS- or MS-SRS.

Clinical analysis of cavernous sinus anatomy, pathologies, diagnostics, surgical management and complications - comprehensive review

For decades, the cavernous sinus (CS) has been the subject of debates and scientific studies aimed at elucidating its anatomical variability, and at choosing the best method for accessing it so that optimal diagnoses and related surgical treatments can be decided. The present review considers a series of issues related to the CS. The anatomy of the CS and its features is explored first, and the most important structures, spaces and morphological variations are considered. This is followed by CS pathology and selected diagnostic methods that have proved useful in therapy, and then the management of these pathologies is discussed. Examples of therapeutic steps that have proved helpful in specific cases are taken from the literature. Finally, the various surgical accesses and complications that can be encountered during invasive interventions in the CS area are discussed. The aim of this study is to summarize up-to-date anatomical and clinical knowledge about the CS, citing the most informative scientific papers and aggregating their results. Morphological variations of the CS are common but have not been well described in the literature.

Critical appraisal of minimally invasive keyhole surgery for intracranial meningioma in a large case series

Background

Meningioma surgery has evolved over the last 20 years with increased use of minimally invasive approaches including the endoscopic endonasal route and endoscope-assisted and gravity-assisted transcranial approaches. As the “keyhole” concept remains controversial, we present detailed outcomes in a cohort series.

Methods

Retrospective analysis was done for all patients undergoing meningioma removal at a tertiary brain tumor referral center from 2008–2021. Keyhole approaches were defined as: use of a minimally invasive “retractorless” approach for a given meningioma in which a traditional larger approach is often used instead. The surgical goal was maximal safe removal including conservative (subtotal) removal for some invasive locations. Primary outcomes were resection rates, complications, length of stay and Karnofsky Performance Scale (KPS). Secondary outcomes were endoscopy use, perioperative treatments, tumor control and acute MRI FLAIR/T2 changes to assess for brain manipulation and retraction injury.

Results

Of 329 patients, keyhole approaches were utilized in 193(59%) patients (mean age 59±13; 30 (15.5%) had prior surgery) who underwent 213 operations; 205(96%) were skull base location. Approaches included: endoscopic endonasal (n = 74,35%), supraorbital (n = 73,34%), retromastoid (n = 38,18%), mini-pterional (n = 20,9%), suboccipital (n = 4,2%), and contralateral transfalcine (n = 4,2%). Primary outcomes: Gross total/near total (>90%) resection was achieved in 125(59%) (5% for petroclival, cavernous sinus/Meckel’s cave, spheno-cavernous locations vs 77% for all other locations). Major complications included: permanent neurological worsening 12(6%), CSF leak 2(1%) meningitis 2(1%). There were no DVTs, PEs, MIs or 30-day mortality. Median LOS decreased from 3 to 2 days in the last 2 years; 94% were discharged to home with favorable 90-day KPS in 176(96%) patients. Secondary outcomes: Increased FLAIR/T2 changes were noted on POD#1/2 MRI in 36/213(17%) cases, resolving in all but 11 (5.2%). Endoscopy was used in 87/139(63%) craniotomies, facilitating additional tumor removal in 55%. Tumor progression occurred in 26(13%) patients, mean follow-up 42±36 months.

Conclusions & relevance

Our experience suggests minimally invasive keyhole transcranial and endoscopic endonasal meningioma removal is associated with comparable resection rates and low complication rates, short hospitalizations and high 90-day performance scores in comparison to prior reports using traditional skull base approaches. Subtotal removal may be appropriate for invasive/adherent meningiomas to avoid neurological deficits and other post-operative complications, although longer follow-up is needed. With careful patient selection and requisite experience, these approaches may be considered reasonable alternatives to traditional transcranial approaches.

Diplopia outcomes following stereotactic radiosurgery for petroclival or cavernous sinus meningiomas: patient series

BACKGROUND

Skull base meningiomas (SBM) often present with diplopia due to compression of the abducens cranial nerve (CN VI). The authors evaluated outcomes in 13 patients diagnosed with SBMs who were experiencing diplopia to determine if Gamma Knife surgery (GKS) resulted in resolution of their symptoms.

OBSERVATIONS

Fourteen patients who were diagnosed with SBMs located in the cavernous sinus, clivus, or petroclival regions and presented with diplopia were treated by GKS. Demographic and clinical data as well as the duration of diplopia prior to GKS were documented. Of the 13 patients included in the study, 1 was excluded because he was lost to follow-up. For the remaining 12, diplopia was resolved in 10 (83%) and no change was noted in 2 (17%). Time to resolution was measured in months, varying from 1 to 30 months, with a median resolution time of 4.5 ± 9.7 months. Of the patients with documented postradiosurgical resolution (n = 10), the median amount of time with diplopia prior to GKS was 1.5 months (range, 1 to 20).

LESSONS

This study showed that diplopia, related to a basal meningioma, may improve following GKS. An earlier time course to radiosurgery after diplopia onset was associated with better outcomes.

Midline Skull Base Meningiomas: Transcranial and Endonasal Perspectives

Simple Summary

Skull base meningiomas have always represented a challenge for neurosurgeons. Despite their histological nature, they may be associated with unfavorable outcomes due to their deep-seated location and the surrounding neurovascular structures. Over time, several corridors have been proposed, each one carrying its own pros and cons. During the last decades, the endoscopic endonasal route has been asserted among the classic routes for a growing number of midline and paramedian lesions. Therefore, the aim of our paper is to present a comprehensive review of the indications and techniques for the management of skull base meningiomas, emphasizing the ambivalent and complementary role of the low and high routes.

Abstract

Skull base meningiomas have always represented a challenge for neurosurgeons. Despite their histological nature, they may be associated with unfavorable outcomes due to their deep-seated location and the surrounding neurovascular structures. The state of the art of skull base meningiomas accounts for both transcranial, or high, and endonasal, or low, routes. A comprehensive review of the pertinent literature was performed to address the surgical strategies and outcomes of skull base meningioma patients treated through a transcranial approach, an endoscopic endonasal approach (EEA), or both. Three databases (PubMed, Ovid Medline, and Ovid Embase) have been searched. The review of the literature provided 328 papers reporting the surgical, oncological, and clinical results of different approaches for the treatment of skull base meningiomas. The most suitable surgical corridors for olfactory groove, tuberculum sellae, clival and petroclival and cavernous sinus meningiomas have been analyzed. The EEA was proven to be associated with a lower extent of resection rates and better clinical outcomes compared with transcranial corridors, offering the possibility of achieving the so-called maximal safe resection.

Skull Base Meningiomas in Patients with Neurofibromatosis Type 2: An International Multicenter Study Evaluating Stereotactic Radiosurgery

Objective  Meningiomas are the second most common tumors in neurofibromatosis type 2 (NF-2). Microsurgery is challenging in NF-2 patients presenting with skull base meningiomas due to the intrinsic risks and need for multiple interventions over time. We analyzed treatment outcomes and complications after primary Gamma Knife radiosurgery (GKRS) to delineate its role in the management of these tumors. Methods  An international multicenter retrospective study approved by the International Radiosurgery Research Foundation was performed. NF-2 patients with at least one growing and/or symptomatic skull base meningioma and 6-month follow-up after primary GKRS were included. Clinical and radiosurgical parameters were recorded for analysis. Results  In total, 22 NF-2 patients with 54 skull base meningiomas receiving GKRS as primary treatment met inclusion criteria. Median age at GKRS was 38 years (10-79 years). Most lesions were located in the posterior fossa (55.6%). Actuarial progression free survival (PFS) rates were 98.1% at 2 years and 90.0% at 5 and 10 years. The median follow-up time after initial GKRS was 5.0 years (0.6-25.5 years). Tumor volume at GKRS was a predictor of tumor control. Lesions >5.5 cc presented higher chances to progress after radiosurgery ( p  = 0.043). Three patients (13.64%) developed adverse radiation effects. No malignant transformation or death due to meningioma or radiosurgery was reported. Conclusions  GKRS is effective and safe in the management of skull base meningiomas in NF-2 patients. Tumor volume deserve greater relevance during clinical decision-making regarding the most appropriate time to treat. GKRS offers a minimally invasive approach of particular interest in this specific group of patients.

The Final Cut: Evolution of Cavernous Sinus Decompression Beyond the Dolenc Cut

BACKGROUND

Meningiomas involving the cavernous sinus (CS) represent a formidable challenge to neurosurgeons. Because of high morbidity, aggressive tumor resection within the CS has been largely replaced by extracavernous tumor resection and decompression of the CS. The widely used Dolenc method involves blind dural transection over the oculomotor nerve, potentially placing the crossing trochlear nerve at risk.

OBJECTIVE

To provide a safer way for the decompression of the CS and at the same time, circumferential resection of the temporal lobe dura.

METHODS

Cadaveric dissection of 8 cadaveric heads (16 sides) was performed. Frontotemporal craniotomy with zygomatic osteotomy was performed. Extradural and intradural dissection of the lateral wall of the CS and free edge of tentorium was performed. Photographic documentation, artistic illustrations, and illustrative video cases are provided.

RESULTS

Three tether points were released: anterior-the meningo-orbital band, lateral-dura over the V2 and V3, and medial-superficial layer of the free edge of tentorium. Transection of the superficial layer of the free edge of the tentorium along its edge, in conjunction with a lateral cut over the temporal convexity, constitutes the final cut, allowing a resection of the lateral CS wall and the circumferential resection of temporal lobe dura.

CONCLUSION

Using the "final cut" technique allows for a circumferential resection of the temporal lobe dura and lateral CS wall while avoiding blind cuts that could put cranial nerves at risk. All dural transections are performed in anatomically separated layers under constant visualization.

Predictors of visual function after resection of skull base meningiomas with extradural anterior clinoidectomy

Skull base meningiomas threatening the optic nerves may require performing an extradural anterior clinoidectomy (EAC) to optimally decompress the optic pathways. The present study evaluated the functional results and morbidity after surgical resection of skull base meningiomas including EAC, focusing on visual acuity (VA) and oculomotricity. Eighty-seven consecutive patients harboring skull base meningiomas who underwent surgical resection that included an EAC between 2003 and 2020 were retrospectively analyzed (86% women, median age 53 years). Decreased visual acuity (DVA) was graded as functional (VA ≥ 5/10) and nonfunctional (VA < 5/10). Statistical analyses were performed on VA and oculomotor nerve (OcN) dysfunction. Ninety surgical procedures were performed. Meningiomas were located at the anterior clinoid process (39%), cavernous sinus (31%), and spheno-orbital (30%) levels. Patients with a preoperative functional vision (normal or functional DVA) had a 90.9% (IC95% = [84.0; 97.8]) probability of preserving it at 6 months and an 84.8% (IC95% = [76.2; 93.5]) probability at last follow-up. Patients with preoperative nonfunctional vision (nonfunctional DVA or blindness) had a 19.0% (IC95% = [2.3; 35.8]) probability of recovery of functional vision at 6 months and a 23.8% (IC95% = [5.6; 42.0]) probability at last follow-up. Preoperative DVA was significantly associated with early postoperative DVA in univariate analyses (p = 0.04). Concerning the OcN, 65% of the patients experienced a postoperative dysfunction, and 78% of those cases recovered. Our study confirms EAC as a useful technical option for skull base meningiomas threatening the optic nerve, especially relevant for patients with preoperative functional vision, and supports early surgical management for these meningiomas.

Management of cavernous sinus meningiomas: Consensus statement on behalf of the EANS skull base section

Introduction

The evolution of cavernous sinus meningiomas (CSMs) might be unpredictable and the efficacy of their treatments is challenging due to their indolent evolution, variations and fluctuations of symptoms, heterogeneity of classifications and lack of randomized controlled trials. Here, a dedicated task force provides a consensus statement on the overall management of CSMs.

Research question

To determine the best overall management of CSMs, depending on their clinical presentation, size, and evolution as well as patient characteristics.

Material and methods

Using the PRISMA 2020 guidelines, we included literature from January 2000 to December 2020. A total of 400 abstracts and 77 titles were kept for full-paper screening.

Results

The task force formulated 8 recommendations (Level C evidence). CSMs should be managed by a highly specialized multidisciplinary team. The initial evaluation of patients includes clinical, ophthalmological, endocrinological and radiological assessment. Treatment of CSM should involve experienced skull-base neurosurgeons or neuro-radiosurgeons, radiation oncologists, radiologists, ophthalmologists, and endocrinologists.

Discussion and conclusion

Radiosurgery is preferred as first-line treatment in small, enclosed, pauci-symptomatic lesions/in elderly patients, while large CSMs not amenable to resection or WHO grade II-III are candidates for radiotherapy. Microsurgery is an option in aggressive/rapidly progressing lesions in young patients presenting with oculomotor/visual/endocrinological impairment. Whenever surgery is offered, open cranial approaches are the current standard. There is limited experience reported about endoscopic endonasal approach for CSMs and the main indication is decompression of the cavernous sinus to improve symptoms. Whenever surgery is indicated, the current trend is to offer decompression followed by radiosurgery.

•

A thorough evaluation of cavernous sinus meningiomas by a multidisciplinary team is mandatory.

•

Microsurgery should be considered for aggressive lesions in young patients.

•

Extended endoscopic approaches can be effective when combined with radiotherapy.

•

Stereotaxic radiotherapy and stereotaxic radiosurgery offer excellent tumour control in small/asymptomatic lesions .

Impact of the Extent of Microsurgical Resection in Sphenopetro-clival Meningiomas Trough a Multistaged Approach: A Volumetric Analysis

Objective  Sphenopetroclival meningiomas (SPCMs) represent a challenge for surgical treatment. The authors used an objective volumetric analysis to assess the effect of the grade of resection and different surgical strategies that may affect the outcome of this tumors. Methods  Over a period of 4 years, patients with SPCMs were treated using a middle versus posterior fossa approach, or a two-stage surgery combining both approaches, based on the tumor location in relation to the petrous ridge and tumor volume. Retrospectively, all cases were analyzed with regard to tumor volume, extent of resection (EOR), functional outcome, and complications. Results  Twenty-seven patients with SPCMs met the inclusion criteria, and the mean follow-up was 24.8 months. Eleven patients underwent a two-stage surgery, while 16 patients had their SPCMs resected via a single craniotomy. Mean EOR was 87.6% and gross total resection was achieved in 48% of patients. Patients with greater EOR had better functional outcomes ( r  = 0.81, p  < 0.01). Greater EOR was not accompanied by a significant increase in surgical complications. There was a trend toward lower postoperative volumes and better EOR with our two-stage approach (2.2 vs. 3.2 cm ³ , p  = 0.09; and 94.1 vs. 91.2%, p  = 0.49, respectively), without an increase in the rate of complications (18.7 vs. 18.2%, p  = 0.5). Conclusion  Staging of the surgical resection of larger tumors may lead to greater EOR, and this strategy should be considered for larger tumors.

Outcomes of Preserving the Hypertrophic Arachnoid Membrane in the Brain-meningioma Interface: Long-term Follow-up

Abnormal hypertrophic arachnoid membranes are often observed in the brain–meningioma interface during microsurgery. They contain fibrosis and tumor cell clusters; however, preservation of the membranes does not always cause recurrence from the brain surface, and the optimal treatments in the interface remain unclear. We investigated the incidence of recurrence on the brain surface following extra-arachnoid dissection with an approach emphasizing preservation of the arachnoid membranes in meningiomas of World Health Organization (WHO) Grade I. The features of dissection cleavages in the interface were prospectively recorded at surgery. The patients were followed up with MR imaging regularly. In total, 111 patients were included. The median follow-up time was 97.0 (interquartile range [IQR] 70.0–124.0) months. The cleavages in the interface were classified into three subgroups: the Extra-H group (n = 56) with extra-arachnoid resection and preservation of hypertrophic arachnoid membranes, the Extra-N group (n = 39) with extra-arachnoid resection having normal membranes, and the Subpial resection group (n = 16). Tumors recurred in 13 (11.7%) patients at both the brain and dura mater (n = 1) or at the dura mater alone (n = 12). The median recurrence-free survival (RFS) of all recurrences was significantly related to the Simpson grades (P <0.01). For brain surface recurrence, the median RFS was not related to the subgroups. The Karnofsky Performance Scores (KPSs) significantly improved in the patients except for the Subpial group at 3 months after surgery. This study revealed that hypertrophic arachnoid membranes preserved on the brain surface rarely caused recurrence from the brain in WHO Grade I meningiomas after a long-term follow-up.

Comparative analysis of the combined petrosal and the pretemporal transcavernous anterior petrosal approach to the petroclival region

OBJECTIVE

The combined petrosal (CP) approach has been traditionally used to resect petroclival meningioma (PCM). The pretemporal transcavernous anterior petrosal (PTAP) approach has emerged as an alternative. A quantitative comparison of both approaches has not been made. This anatomical study compared the surgical corridors afforded by both approaches and identified key elements of the approach selection process.

METHODS

Twelve cadaveric specimens were dissected, and 10 were used for morphometric analysis. Groups A and B (n = 5 in each) underwent the CP and PTAP approaches, respectively. The area of drilled clivus, lengths of cranial nerves (CNs) II-X, length of posterior circulation vessels, surgical area of exposure of the brainstem, and angles of attack anterior and posterior to a common target were measured and compared.

RESULTS

The area of drilled clivus was significantly greater in group A than group B (mean ± SD 88.7 ± 17.1 mm2 vs 48.4 ± 17.9 mm2, p < 0.01). Longer segments of ipsilateral CN IV (52.4 ± 2.33 mm vs 46.5 ± 3.71 mm, p < 0.02), CN IX, and CN X (9.91 ± 3.21 mm vs 0.00 ± 0.00 mm, p < 0.01) were exposed in group A than group B. Shorter portions of CN II (9.31 ± 1.28 mm vs 17.6 ± 6.89 mm, p < 0.02) and V1 (26.9 ± 4.62 mm vs 32.4 ± 1.93 mm, p < 0.03) were exposed in group A than group B. Longer segments of ipsilateral superior cerebellar artery (SCA) were exposed in group A than group B (36.0 ± 4.91 mm vs 25.8 ± 3.55 mm, p < 0.02), but there was less exposure of contralateral SCA (0.00 ± 0.00 mm vs 7.95 ± 3.33 mm, p < 0.01). There was no statistically significant difference between groups with regard to the combined area of the exposed cerebral peduncles and pons (p = 0.75). Although exposure of the medulla was limited, group A had significantly greater exposure of the medulla than group B (p < 0.01). Finally, group A had a smaller anterior angle of attack than group B (24.1° ± 5.62° vs 34.8° ± 7.51°, p < 0.03).

CONCLUSIONS

This is the first study to quantitatively identify the advantages and limitations of the CP and PTAP approaches from an anatomical perspective. Understanding these data will aid in designing maximally effective yet minimally invasive approaches to PCM.

Streamlining brain tumor surgery care during the COVID-19 pandemic: A case-control study

BACKGROUND

The COVID-19 pandemic forced a reconsideration of surgical patient management in the setting of scarce resources and risk of viral transmission. Herein we assess the impact of implementing a protocol of more rigorous patient education, recovery room assessment for non-ICU admission, earlier mobilization and post-discharge communication for patients undergoing brain tumor surgery.

METHODS

A case-control retrospective review was undertaken at a community hospital with a dedicated neurosurgery and otolaryngology team using minimally invasive surgical techniques, total intravenous anesthesia (TIVA) and early post-operative imaging protocols. All patients undergoing craniotomy or endoscopic endonasal removal of a brain, skull base or pituitary tumor were included during two non-overlapping periods: March 2019-January 2020 (pre-pandemic epoch) versus March 2020-January 2021 (pandemic epoch with streamlined care protocol implemented). Data collection included demographics, preoperative American Society of Anesthesiologists (ASA) status, tumor pathology, and tumor resection and remission rates. Primary outcomes were ICU utilization and hospital length of stay (LOS). Secondary outcomes were complications, readmissions and reoperations.

FINDINGS

Of 295 patients, 163 patients were treated pre-pandemic (58% women, mean age 53.2±16 years) and 132 were treated during the pandemic (52% women, mean age 52.3±17 years). From pre-pandemic to pandemic, ICU utilization decreased from 92(54%) to 43(29%) of operations (p<0.001) and hospital LOS≤1 day increased from 21(12.2%) to 60(41.4%), p<0.001, respectively. For craniotomy cohort, median LOS was 2 days for both epochs; median ICU LOS decreased from 1 to 0 days (p<0.001), ICU use decreased from 73(80%) to 29(33%),(p<0.001). For endonasal cohort, median LOS decreased from 2 to 1 days; median ICU LOS was 0 days for both epochs; (p<0.001). There were no differences pre-pandemic versus pandemic in ASA scores, resection/remission rates, readmissions or reoperations.

CONCLUSION

This experience suggests the COVID-19 pandemic provided an opportunity for implementing a brain tumor care protocol to facilitate safely decreasing ICU utilization and accelerating discharge home without an increase in complications, readmission or reoperations. More rigorous patient education, recovery room assessment for non-ICU admission, earlier mobilization and post-discharge communication, layered upon a foundation of minimally invasive surgery, TIVA anesthesia and early post-operative imaging are possible contributors to these favorable trends.

Extradural anterior clinoidectomy in surgical management of clinoidal meningiomas

Background

Despite the recent advances in skull base surgery, microsurgical techniques, and neuroimaging, yet surgical resection of clinoidal meningiomas is still a major challenge. In this study, we present our institution experience in the surgical treatment of anterior clinoidal meningiomas highlighting the role of extradural anterior clinoidectomy in improving the visual outcome and the extent of tumor resection. This is a prospective observational study conducted on 33 consecutive patients with clinoidal meningiomas. The surgical approach utilized consisted of extradural anterior clinoidectomy, optic canal deroofing with falciform ligament opening in all patients. The primary outcome assessment was visual improvement and secondary outcomes were extent of tumor resection, recurrence, and postoperative complications.

Results

The study included 5 males and 28 females with mean age 49.48 ± 11.41 years. Preoperative visual deficit was present in 30 (90.9%) patients. Optic canal involvement was present in 24 (72.7%) patients, ICA encasement was in 16 (48.5%), and cavernous sinus invasion in 8 (24.2%). Vision improved in 21 patients (70%), while 6 patients (20%) had stationary course and 1 patient (3%) suffered postoperative new visual deterioration. Gross total resection was achieved in 24 patients (72.7%). The main factors precluding total removal were cavernous sinus involvement and ICA encasement. Mortality rate was 6.1%; mean follow-up period was 27 ± 13 months.

Conclusions

In this series, the use of extradural anterior clinoidectomy provided a favorable visual outcome and improved the extent of resection in clinoidal meningioma patients.

Predicting Discharge Disposition Following Meningioma Resection Using a Multi-Institutional Natural Language Processing Model

BACKGROUND

Machine learning (ML)-based predictive models are increasingly common in neurosurgery, but typically require large databases of discrete variables for training. Natural language processing (NLP) can extract meaningful data from unstructured text.

OBJECTIVE

To present an NLP model that predicts nonhome discharge and a point-of-care implementation.

METHODS

We retrospectively collected age, preoperative notes, and radiology reports from 595 adults who underwent meningioma resection in an academic center from 1995 to 2015. A total of 32 algorithms were trained with the data; the 3 best performing algorithms were combined to form an ensemble. Predictive ability, assessed by area under the receiver operating characteristic curve (AUC) and calibration, was compared to a previously published model utilizing 52 neurosurgeon-selected variables. We then built a multi-institutional model by incorporating notes from 693 patients at another center into algorithm training. Permutation importance was used to analyze the relative importance of each input to model performance. Word clouds and non-negative matrix factorization were used to analyze predictive features of text.

RESULTS

The single-institution NLP model predicted nonhome discharge with AUC of 0.80 (95% CI = 0.74-0.86) on internal and 0.76 on holdout validation compared to AUC of 0.77 (95% CI = 0.73-0.81) and 0.74 for the 52-variable ensemble. The multi-institutional model performed similarly well with AUC = 0.78 (95% CI = 0.74-0.81) on internal and 0.76 on holdout validation. Preoperative notes most influenced predictions. The model is available at http://nlp-home.insds.org.

CONCLUSION

ML and NLP are underutilized in neurosurgery. Here, we construct a multi-institutional NLP model that predicts nonhome discharge.

Long-term disease control and treatment outcomes of stereotactic radiosurgery in cavernous sinus meningiomas

BACKGROUND

Most of the current knowledge on the clinical effects of stereotactic radiosurgery (SRS) on the treatment of cavernous sinus meningiomas (CSM) is based on series with limited follow-up. However, determining the role of radiation in a tumor with slow disease progression such as CSM necessitates long term follow up.

OBJECTIVE

To review and pool metadata in the literature to determine the long-term outcomes of SRS with respect to clinical and radiographic tumor control of CSM.

METHODS

A systematic search was conducted following MOOSE guidelines. Results were screened against predefined criteria, which excluded studies with a median follow-up less than 5 years. The incidences of each outcome were calculated using random-effects metanalysis of proportions.

RESULTS

Seven studies met the inclusion criteria, comprising 645 patients. The median follow-up was 74 months (range 62-87). Progression-free-survival at 5, 10, and 15 years was 93.4% (95% CI 89.1-96.7%), 84.9% (95% CI 77-91.4%), and 81.3% (95% CI 74-87.7%), respectively. Clinical response to SRS at last follow-up defined as improvement of cranial nerve deficits was found in in 36.4% (95% CI 26.3-47.1%) of patients, while worsening or onset of new cranial nerve deficits was found in 11.5% (95% CI 7.9-15.7%). Radiological regression was found in 57.8% (95% CI 43-71.8%), while tumor progression was found in 8.5% (95% CI 5.2-12.6%).

CONCLUSION

SRS achieves excellent disease control and radiographic response in CSM. Although the risk of long-term cranial neuropathies is minimal, it is relatively higher to what has been previously reported in early series with limited follow-up.

Cavernous Sinus Meningioma with Orbital Involvement: Algorithmic Decision-Making and Treatment Strategy

Cavernous sinus meningioma (CSM) with orbital involvement presents a unique challenge to modern-day neurosurgeons. In the modern era of preventive medicine with enhanced screening tools, physicians encounter CSM more frequently. An indolent natural history, late clinical presentation, close proximity to vital neurovascular structures, poor tumor-to-normal tissue interface, and high risk of iatrogenic morbidity and mortality with aggressive resection add to the complexity of decision-making and optimal management of these lesions. The clinical dilemma of deciding whether to observe or intervene first for asymptomatic lesions remains an enigma in current practice. The concepts of management for CSM with orbital involvement have gradually evolved from radical resection to a more conservative surgical approach with maximal safe resection, with the specific goals of preserving function and reducing proptosis. This change in surgical attitude has enabled better long-term functional outcomes with conservative approaches as compared with functionally disabled outcomes resulting from the pursuit of anatomical cure from disease with radical resection. The advent of stereotactic radiosurgery as an adjunct tool to treat residual CSM has greatly shaped our resection principles and planning. Interdisciplinary collaboration for multimodality management is key to successful management of these difficult to treat lesions and tailor management as per individual's requirement.

Comparison of clinical outcomes in patients who underwent Gamma Knife radiosurgery for parasellar meningiomas with or without prior surgery

Background

Parasellar meningioma is a common benign tumour in brain. Both surgery and radiosurgery are important treatment modalities for this tumour. The study was designed to investigate whether prior surgery would affect treatment outcomes of patients with parasellar meningiomas after management with Gamma Knife radiosurgery.

Methods

A total of 93 patients who received Gamma Knife surgery were included in this retrospective study. There were 30 males and 63 females, with a median age of 48.6 years (range, 15.2–78.7 years). Prior surgery was performed in 45 patients. The median tumor volume was 5.02 cm³ (range 1.07–35.46 cm³) and median marginal dose was 12 Gy (range 10–15 Gy). The mean imaging follow-up and clinical follow-up periods were 40.7 and 52.7 months, respectively.

Results

In the group without prior surgery, 31 patients had improvement of preexisting symptoms; and in the group with prior surgery, 20 patients were noted to improve. The difference in symptom improvement between the two groups reached statistical significance (P = 0.009). Patients with prior surgery were more likely to have stable symptoms after Gamma Knife surgery (P = 0.012). Tumor recurrence was reported in 8 patients out of 45 patients with prior surgery, and 3 patients out of 48 patents without prior surgery (P = 0.085). After Gamma Knife surgery, 5 and 4 patients in two groups developed new neurological symptoms, respectively (P = 0.651). Cox regression analysis identified follow-up period as prognostic factor of progression-free survival. Ordinal logistic regression analysis identified surgery prior to Gamma Knife surgery as an unfavorable factor of symptom change.

Conclusion

Gamma Knife radiosurgery provided long-term effective tumor control and better symptom recovery compared with those with prior surgery. Patients with surgery before Gamma Knife radiosurgery were more likely to have stable symptoms. Further analyses indicated that long follow-up is essential to determine the efficacy of radiosurgery for parasellar meningiomas. Further study needs to include more patients with longer follow-up to draw a more solid conclusion.

Parasellar Meningiomas

Parasellar spaces remain particularly singular, comprising the most important neurovascular structures such as the internal carotid artery and optic, oculomotor, and trigeminal nerves. Meningiomas are one of the most frequent tumors arising from parasellar spaces. In this location, meningiomas remain mostly benign tumors with WHO grade I and a meningothelial subtype. Progestin intake should be investigated and leads mostly to conservative strategies. In the case of benign nonsymptomatic tumors, observation should be proposed. Tumor growth will lead to the proposition of surgery or radiosurgery. In the case of an uncertain diagnosis and an aggressive pattern, a precise diagnosis is required. For cavernous sinus and Meckel's cave lesions, complete removal is rarely considered, leading to the proposition of an endoscopic endonasal or transcranial biopsy. Optic nerve decompression could also be proposed via these approaches. A case-by-case discussion about the best approach is recommended. A transcranial approach remains necessary for tumor removal in most cases. Vascular injury could lead to severe complications. Cerebrospinal fluid leakage, meningitis, venous sacrifice, visual impairment, and cranial nerve palsies are more frequent complications. Pituitary dysfunctions are rare in preoperative assessment and in postoperative follow-up but should be assessed in the case of meningiomas located close to the pituitary axis. Long-term follow-up is required given the frequent incomplete tumor removal and the risk of delayed recurrence. Radiosurgery is relevant for small and well-limited meningiomas or intra-cavernous sinus postoperative residue, whereas radiation therapy and proton beam therapy are indicated for large, extended, nonoperable meningiomas. The place of the peptide receptor radionuclide therapyneeds to be defined. Targeted therapy should be considered in rare, recurrent, and aggressive parasellar meningiomas.

Cavernous sinus meningioma

Cavernous sinus meningioma (CSM) presents a management challenge to present-day neurosurgeons. Lack of adequate understanding of the natural history of these lesions, the early involvement of vital neurovascular structures, the absence of clear tissue planes with normal surrounding structures, and a high rate of aggressive surgery-related morbidity each pose management dilemmas for neurosurgeons. Over the past few decades, the enthusiasm of the neurosurgical community has shifted from aggressive microsurgical resection to maximal safe resection and institution of adjuvant radiotherapy, if necessary. This paradigm shift has ensured better functional outcome in treated patients. This chapter has been designed to discuss the current treatment algorithm and the importance of multimodality management for optimal outcome in patients with CSM. The technical aspects of this approach to management are presented, and the various treatment options are compared.

The historical perspective in approaches to the spheno-petro-clival meningiomas

The current literature regarding surgical treatment for tumors in the sphenopetroclival (SPC) region is merely scarce. Through a comprehensive literature review, we investigated the indications, outcomes, and complications of different surgical approaches to the SPC meningiomas. Given its complicated relationship between these slow-progression tumors and some critical neurovascular structures in the SPC region, surgical treatment of these tumors faces the challenge of achieving a maximal grade of resection, while preserving patient functionality. The development of new surgical techniques and approaches in recent years have permitted the advancement in the treatment of these tumors, with acceptable rates of morbidity and mortality. The choice of a surgical approach as a treatment for the lesion depends mainly on the type of tumor extension, surgeon's preferences, and the displacement of neurovascular structures. Rather than focusing on one single strategy of treatment, the skull-base surgeon should tailor the approach based on the origin and features of the lesion; as well as the peculiarities of the surgical anatomy. This strategy aims to decrease morbidity and to optimize tumor resection and patient quality of life.