Transbasal versus endoscopic endonasal versus combined approaches for olfactory groove meningiomas: importance of approach selection

Interdisciplinary Management of Skull Base Tumors

OBJECTIVE

Endoscopic endonasal skull base surgery has gained acceptance worldwide. Comparative analysis has demonstrated that endoscopic skull base surgery may have advantages for many pathologies of the anterior skull base, e. g., sinonasal malignant tumors; pathologies of the central skull base, e. g., pituitary adenomas, craniopharyngiomas; well-selected cases of planum sphenoidale and tuberculum sellae meningiomas; or for clival lesions, e. g., chordomas, chondrosarcomas, or selected meningiomas. Over the past three decades, interdisciplinary surgical teams, consisting of otolaryngologists and neurosurgeons, have provided detailed anatomical knowledge, suggested new approaches or modifications of established surgical techniques, and offered continued surgical education.

METHOD

A review of pertinent literature was conducted with an emphasis on interdisciplinary endoscopic surgery of skull base lesions.

RESULTS

Based on the authors̓ surgical experience in two different interdisciplinary endoscopic skull base centers, the authors classify approaches for endoscopic endonasal skull base surgery, describe indications, and key anatomic landmarks for common pathologies, and highlight surgical techniques to avoid complications.

CONCLUSION

Interdisciplinary endonasal endoscopic surgery combines surgical expertise, improves resection rates for many pathologies, and minimizes morbidity by reducing the incidence of surgical complications.

Endoscopic endonasal approach for olfactory groove meningioma resection: Strategies and outcomes in a retrospective case series

OBJECTIVE

Though the endoscopic endonasal approach (EEA) is a widely accepted treatment for skull base tumors, the specific use of EEA for olfactory groove meningiomas (OGMs) is debated, with variable outcomes reported in the literature. We review the surgical results of OGM resections for one surgeon including the operative approach, surgical nuances, and outcomes, with a focus on factors relating to patient selection which favor EEA over transcranial approaches.

METHODS

We retrospectively reviewed thirteen cases of endoscopic endonasal resection of olfactory groove meningiomas. Patient characteristics, clinical characteristics, surgical outcomes, and complications were analyzed. Extent of resection was determined based on volumetric analysis of pre- and postoperative MRI.

RESULTS

Anatomic characteristics that render a tumor difficult to access fully are lateral extension beyond the mid-orbit and anterior extension to the falx. Simpson Grade I resection was achieved in 11/13 (84.6 %) cases. Mean pre-operative tumor volume was 8.99 cm3 (range 2.19-16.79 cm3), and 92 % of tumors were WHO grade I. We demonstrate 2 cases of smell preservation, possible with small unilateral tumors and tumors that are confined to either the anterior or posterior portion of the cribriform plate. The post-operative CSF leak rate was 7.7 %, without prophylactic lumbar CSF drainage. The mortality rate was 7.7 % (n = 1) after infectious complications following CSF leak.

CONCLUSIONS

Endoscopic endonasal resection of olfactory groove meningiomas is an effective and safe operative method with outcomes and complication rates comparable to transcranial approaches. Key considerations include careful patient selection and familiarity with technical nuances of endoscopic endonasal approach for this specific tumor type.

Fully Endoscopic Supraorbital Approach for Anterior Cranial Base Meningiomas

BACKGROUND

Anterior cranial base meningiomas include those meningiomas originating from the tuberculum sellae, the planum sphenoidale, or the olfactory groove, with surgical excision being the main treatment modality for these tumors. Conventional microscopic and endoscope-assisted versions of the supraorbital keyhole approach via an eyebrow incision emerged into minimally invasive options that are frequently utilized nowadays for treating these tumors. At the early attempts of endoscope-assisted cranial surgery, it was noted that rigid endoscopes enabled overcoming the problem of suboptimal visualization when small exposures are used. The technical specifications and design of the currently available rigid endoscopes are associated with a group of unique features that define the endoscopic view and lay the basis for its superiority over the microscopic view during brain surgery. Notwithstanding, the fully endoscopic or endoscope-controlled version of the supraorbital keyhole approach is not routinely practiced by neurosurgeons, with few series published so far. In this chapter we elaborate on the surgical technique and nuances of the fully endoscopic supraorbital approach for anterior cranial base meningiomas.

METHODS

From a prospective database of endoscopic procedures maintained by the senior author, clinical data, imaging studies, operative charts, and videos of cases undergoing fully endoscopic excision of anterior cranial base meningiomas via supraorbital approach were retrieved and analyzed. The pertinent literature was also reviewed.

RESULTS

The surgical technique of the fully endoscopic supraorbital approach for anterior cranial base meningiomas was formulated.

CONCLUSION

The fully endoscopic supraorbital approach for anterior cranial base meningiomas has many advantages over the conventional procedures. In our hands, the technique has proven to be feasible, efficient, and minimally invasive with excellent results.

Effects of Endoscopic Sinus Surgery on Olfactory Function

PURPOSE OF REVIEW

To review the effects of endoscopic sinus surgery and endonasal approaches to the skull base on olfaction.

RECENT FINDINGS

Advancements in endonasal endoscopic approaches to the sinuses and skull base allow for direct treatment of a variety of sinonasal and skull base diseases. However, these extended approaches will often require manipulation of normal anatomical structures and the olfactory neuroepithelium. Depending on the planned procedure and extent of disease, the prognosis of olfactory perception can vary significantly among patients. Endoscopic sinonasal surgical procedures may impact olfaction. Optimizing olfactory function requires proper surgical techniques, gentle handling of tissue, and perioperative care. Surgeons must discuss objectives and manage patient expectations. Routine olfactory assessment is crucial in surgical work-up and follow-up. Preserving anatomical structures while addressing the obstruction of the olfactory cleft helps to prevent decreased olfactory threshold. However, smell identification and discrimination do not always correlate with sinonasal anatomy.

Olfaction preservation in olfactory groove meningiomas: a systematic review

Olfactory groove meningiomas (OGM) are a skull base neoplasm that represents between 8 and 13% of all intracranial meningiomas. Approach selection focuses on achieving frontal lobe decompression, gross total resection and vision preservation. Recently, there has been a focus on olfaction and considering its preservation as a quality-of-life outcome measure. An electronic search of the databases Medline, Scopus, Embase, Web of Science and Cochrane library databases was performed and data extracted according 2020 Preferred Reporting Items of Systematic Reviews and Meta-Analyses (PRISMA) statement. Six articles were selected for inclusion mainly based due to reporting quantitative outcomes for olfaction assessed by a smell identification test (e.g. sniffin' sticks). Objective olfaction preservation can be achieved with a variety of surgical approaches. More research which includes objective assessment of olfactory function and ideally as well QoL outcome measures is needed to further optimize the treatment pathways in OGM patients.

Olfactory Groove Meningiomas: Comprehensive assessment between the different microsurgical transcranial approaches and the Endoscopic Endonasal Approaches, systematic review and metanalysis on behalf of the EANS skull base section

•OGM surgery is much more complex than a simple debate of "from above or from below" (transcranial vs endoscopic).•Lateral Sub-frontal and Superior Interhemispheric seem the most effective, superior and versatile approaches for OGM.•Minimally Invasive Transcranial approaches showed no inferiority in OGM sized <4 ​cm.•Endoscopic Endonasal Approaches showed inferior results in surgical and in functional outcomes for OGM.

Clinical considerations for open versus endoscopic approaches in skull base surgery

PURPOSE OF REVIEW

We aim to distill the current body of evidence to consider when selecting an endoscopic versus open approach to address cranial base disease. We evaluate the evolution of modern surgical techniques and their respective limitations.

RECENT FINDINGS

Greater understanding of the role of tumor biology in relation to patient outcomes has led to increasingly sophisticated treatment algorithms. This combined with further development of advanced instrumentation and technique has led to the adoption of new surgical corridors previously unapproachable via traditional surgery.

SUMMARY

Endoscopic and open craniofacial approaches both remain important surgical techniques in the management of cranial base tumors. The modern skull base surgeon may employ a combination of approaches to optimize tumor extirpation while preserving functional outcomes. Patient history, anatomic tumor extent, histology, and functional goals should be considered thoroughly when planning any surgical intervention.

Anterior Skull Base Meningioma: Surgical Approach and Complication Avoidance

Introduction  Endoscopic endonasal approach (EEA) and keyhole transcranial approaches (TCAs) are being increasingly used in anterior skull base meningioma (ASBM) surgery. Objective  We compare tumor resection rates and complication profiles of EEA and supraorbital keyhole approach (SOKHA) with conventional TCAs. Methods  Fifty-four patients with ASBM (olfactory groove meningioma [OGM], n  = 19 and planum sphenoidale/tuberculum sellae meningioma [PSM/TSM], n  = 35) operated at a single center over 7 years were retrospectively analyzed. Results  The overall rate of gross total resection (GTR) was higher in OGM (15/19, 78.9%) than PSM-TSM group (23/35, 65.7%, p  = 0.37). GTR rate with OGM was 90% and 75% with TCA and EEA. Death ( n  = 1) following medical complication (TCA) and cerebrospinal fluid leak requiring re-exploration ( n  = 2, one each in TCA and EEA) accounted for the major complications in OGM. For the PSM/TSM group, the GTR rates were 73.3% ( n  = 11/15), 53.8% ( n  = 7/13), and 71.4% ( n  = 5/7) with TCA, EEA, and SOKHA, respectively. Seven patients (20%) of PSM-TSM developed major postoperative complications including four deaths (one each in TCA and SOKHA, and two in EEA groups) and three visual deteriorations. Direct and indirect vascular complications were common in lesser invasive approaches to PSM-TSM especially if the tumor has encased intracranial arteries. Conclusion  No single approach is applicable to all ASBMs. TCA is still the best approach to obtain GTR but has tissue trauma-related problems. SOKHA may be a good alternative to TCA in selected PSM-TSMs, while EEA may be an alternate option in some OGMs. A meticulous patient selection is needed to derive reported results of EEA for PSM-TSM.

Smell Outcomes in Olfactory Groove Meningioma Resection Through Unilateral vs Bilateral Transcranial Approaches: A Systematic Review and Meta-analysis

OBJECTIVE

Olfactory disturbance is a common complication that occurs following the surgical resection of olfactory groove meningiomas (OGMs). There is little evidence on the best trans-cranial approach that minimizes rates of postoperative olfactory disturbance. The objective of this systematic review and meta-analysis is to compare smell outcomes after OGM resection in unilateral vs bilateral trans-cranial approaches.

METHODS

A systematic review of the literature and meta-analysis was conducted using PUBMED, SCOPUS, and EMBASE in accordance with the PRISMA guidelines. The primary endpoint was incidence of new olfactory disturbance defined as either anosmia, and/or hyposmia. Patients were classified as undergoing either a unilateral or bilateral approach. Data on presence of new post-operative olfactory deficits was used to generate standardized mean differences and 95% confidence intervals.

RESULTS

Ten studies met the inclusion criteria for quantitative analysis, comprising 342 patients. A total of 216 patients underwent unilateral approaches while 126 underwent resection via bilateral approach. 17.1% in the unilateral approach cohort experienced new postoperative olfactory disturbance following resection, compared to 19.2% of patients in the bilateral approach cohort. Forest plot did not reveal any significant difference in the incidence of new olfactory disturbance following either unilateral or bilateral approaches.

CONCLUSIONS

Our data suggests that there is no significant difference between the investigated trans-cranial approaches and postoperative olfactory disturbances. Accordingly, our study suggests that further investigation with introduced experimental control could provide more insight into the capabilities and drawbacks of each route in relation to olfactory outcomes.

Stereotactic Radiosurgery for Olfactory Groove Meningiomas: An International, Multicenter Study

BACKGROUND

Stereotactic radiosurgery (SRS) is increasingly considered for selected olfactory groove meningiomas (OGMs).

OBJECTIVE

To investigate the safety and efficacy of SRS for OGMs.

METHODS

From 20 institutions participating in the International Radiosurgery Research Foundation, we pooled patients who underwent SRS for histologically confirmed or radiologically suspected WHO grade I OGMs and were followed for 6 mo or more after the SRS.

RESULTS

In total, 278 (median age 57 yr) patients underwent SRS for histologically confirmed (29%) or radiologically suspected (71%) WHO grade I OGMs Median treatment volume was 4.60 cm3 (range: 0.12-27.3 cm3), median prescription dose was 12 Gy, and median dose to the olfactory nerve was 11.20 Gy. During median post-SRS imaging follow-up of 39 mo (range: 6-240 mo), 43% of patients had partial or marginal response, 54% of patients had stable disease, and 3% of patients experienced progression. During median post-SRS clinical follow-up of 51 mo (range: 6-240 mo), 36 (13%) patients experienced clinical and/or radiological adverse radiation events (AREs). Elevated risk of AREs was associated with larger OGM volume (P = .009) and pre-SRS peritumoral T2/fluid-attenuated inversion-recovery signal abnormalities (P < .001). After the SRS, olfaction remained stable, improved, or deteriorated in 90%, 8%, and 2% of patients, respectively. Complete post-SRS anosmia was predicted by partial/complete anosmia before the SRS (odds ratio [OR] = 83.125; 95% CI [24.589-281.01], P < .001) and prior resection of OGM (OR = 3.919; 95% CI [1.713-8.970], P = .001).

CONCLUSION

SRS is associated with durable local control of the majority of OGM patients with acceptable safety profile. SRS allows preservation or improvement of olfactory function in the majority of OGM patients.

Comparison of Three Surgical Approaches for Frontobasal Meningiomas: Purely Endoscopic Endonasal, Purely Microscopic Bifrontal Transcranial, and Combined Endoscopic and Microscopic Supraorbital Transciliary Approaches

ABSTRACT

Surgical removal of frontobasal meningiomas (FBMs) can be achieved using different techniques, including endoscopic, transcranial, and combined approaches. The advantages and disadvantages of the outcomes of these approaches should be compared to provide the most convenient surgical treatment to the patient. This study aimed to compare 3 surgical approaches for FBMsin terms of outcomes and determine the superiority of each on the basis of anatomical, surgical, and clinical efficacy. Systematic review was performed to identify studies comparing techniques for the surgical removal of FBMs. Each group included 13 patients; 39 patients with FBMshad undergone surgery. These groups were endoscopic endonasal approach (EEA), microscopic bifrontal transcranial approach (MTA), and endoscopic plus microscopic combined supraorbital transciliary approach (STA) groups. Data on the demographics of patient population, pre- and post-operative neurological examination, tumor properties, imaging studies, and surgical complications were extracted. The mean age at the time of surgery for the patient population was 53.2 years. Among the groups, no statistically significant differences were observed with regard to sex (P = 0.582). The mean follow-up time was 56.7 months. A statistically significant difference was observed in the mean tumor volume among the groups; the MTA group showed the highest mean tumor volume. However, no significant difference was found in the mean tumor volume between EEA and STA groups. Regarding operation duration, the STA group had the shortest operation time (mean = 281.5 minutes), whereas the average surgical duration in MTA group was the longest (mean = 443.8 minutes). The average bleeding volume was highest in the MTA group (mean = 746.2 ml) and lowest in the EEA group (mean = 320.8 ml). Tumor removal was incomplete in three patients (two in the EEA group and one in the MTA group). Recurrence was detected in two cases. One patient with recurrence was operated using the endoscopic surgical approach, whereas the other patient underwent the microscopic bifrontal approach. Post-operative hyposmia/anosmia or decreased olfactory function was the most common complication observed in 5 patients, 2 patients each in the EEA and MTA groups and one in the STA group. The second most common complication was wound infection in one patient in the MTA group and two patients in the STA group (7.7%). Both cerebrospinal fluid (CSF) leakage and meningitis were present in two patients (5.1%), one patient each from the EEA and STA groups. Pre-operative visual disturbances were reported in 13 patients (33.3%), all of which resolved post-operatively No statistical differences were found among the groups. Mortality occurred in a patient in the MTA group (2.6%) caused by cardiac arrest on post-operative day 1. This is the first study comparing the surgical outcomes of three surgical approaches for FBMs. Although recent literature suggests that both endoscopic and transcranial approaches have their own advantages and disadvantages, the authors showed that none of the surgical approaches have obvious superiority over the others with regard to outcomes. Thus, the selection of the ideal surgical approach should be based on surgical experience and tumor characteristics.

The endoscope-assisted supraorbital "keyhole" approach for anterior skull base meningiomas: an updated meta-analysis

INTRODUCTION

The gold-standard treatment for symptomatic anterior skull base meningiomas is surgical resection. The endoscope-assisted supraorbital "keyhole" approach (eSKA) is a promising technique for surgical resection of olfactory groove (OGM) and tuberculum sellae meningioma (TSM) but has yet to be compared with the microscopic transcranial (mTCA) and the expanded endoscopic endonasal approach (EEA) in the context of existing literature.

METHODS

An updated study-level meta-analysis on surgical outcomes and complications of OGM and TSM operated with the eSKA, mTCA, and EEA was conducted using random-effect models.

RESULTS

A total of 2285 articles were screened, yielding 96 studies (2191 TSM and 1510 OGM patients). In terms of effectiveness, gross total resection incidence was highest in mTCA (89.6% TSM, 91.1% OGM), followed by eSKA (85.2% TSM, 84.9% OGM) and EEA (83.9% TSM, 82.8% OGM). Additionally, the EEA group had the highest incidence of visual improvement (81.9% TSM, 54.6% OGM), followed by eSKA (65.9% TSM, 52.9% OGM) and mTCA (63.9% TSM, 45.7% OGM). However, in terms of safety, the EEA possessed the highest cerebrospinal fluid leak incidence (9.2% TSM, 14.5% OGM), compared with eSKA (2.1% TSM, 1.6% OGM) and mTCA (1.6% TSM, 6.5% OGM). Finally, mortality and intraoperative arterial injury were 1% or lower across all subgroups.

CONCLUSIONS

In the context of diverse study populations, the eSKA appeared not to be associated with increased adverse outcomes when compared with mTCA and EEA and offered comparable effectiveness. Case-selection is paramount in establishing a role for the eSKA in anterior skull base tumours.

Modern endoscopic skull base neurosurgery

INTRODUCTION

Since the early use of the endoscopic view for treating simple intrasellar pituitary adenomas, the skull base surgery has experienced an unprecedented revolution elevating the treatment of skull base lesions to the next level in proficiency and excellence of care.

METHODS

We have reviewed the preclinical and clinical evidence supporting the use of the endoscope in the treatment of skull base lesions. In this article, we aim to discuss and provide a wide view of the current indications and future perspectives of the endoscopic endonasal approaches (EEA) and of the endoscopic transcranial approaches.

RESULTS

As in the development of any other technique, EEA have gone through a transformation process from theoretical anatomic models to a pragmatic clinical use. Along the way, EEA have required several modifications, as well as pushbacks in the application of this technique in some indications. This process has resulted in the provision of an additional tool to the current surgical armamentarium that allows the skull base surgeon to face most challenging lesions along the skull base.

CONCLUSIONS

The judicious combination of transcranial and endoscopic-transnasal approaches warrants highest chances of achieving satisfactory tumors resection with a reduced risk of complications.

The transbasal approach to the anterior skull base: surgical outcome of a single-centre case series

A variety of sinonasal tumours, meningiomas or other lesions of the anterior skull base involve the paranasal sinuses and the periorbital area. The transbasal approach (TBA) has turned out to be a feasible technique to reach those lesions. A retrospective review at a neurosurgical university department between November 2007 and January 2020 with adult patients who underwent resection of oncologic pathologies through TBA. Surgical technique, extent of resection (EOR), clinical outcome and postoperative complications were analysed. 18 TBAs between November 2007 and January 2020 were performed. Median age was 62 (range 25–83), 7 female and 11 male patients. Gross total resection rate was 85.8% throughout all entities. Four (22.2%) patients suffered from WHO°I meningiomas and 14 (77.7%) from other extra-axial lesions. Preoperative Karnofsky Performance Status Scale (KPSS) was 80% (range 40–90), postoperative KPSS 80% (range 20–100). Rate of postoperative complications requiring intervention was 16.7%. Median follow-up was 9.8 (range 1.2–71.8) months. Modifications and extensions of the classic TBA are not mandatory. Complete resection can be performed under functional and cosmetic-preserving aspects. Second-step procedures such as transnasal approaches may be performed to avoid high morbidity of more aggressive TBAs, if necessary. Surgical considerations should be kept simple and straightforward.

Minimally Invasive Approaches to Anterior Skull Base Meningiomas

Objective Anterior skull base meningiomas include olfactory groove, planum sphenoidale, and tuberculum sellae lesions. Traditionally, standard craniotomy approaches have been used to access meningiomas in these locations. More recently, minimally invasive techniques including supraorbital and endonasal endoscopic approaches have gained favor; however there are limited published series comparing the use of these two techniques for these meningiomas. Using our patent database, we identified patients who underwent these two approaches, and conducted a retrospective chart review to compare outcomes between these two techniques.

Methods A total of 32 patients who underwent minimally invasive approaches were identified: 20 supraorbital and 11 endoscopic endonasal. Radiographic images, presenting complaints and outcomes, were analyzed retrospectively. The safety of each approach was evaluated.

Results The mean extent of resection through a supraorbital approach was significantly greater than that of the endoscopic endonasal approach, 88.1 vs. 57.9%, respectively (p = 0.016). Overall, preoperative visual acuity and anopsia deficits were more frequent in the endonasal group that persisted postoperatively (visual acuity: p = 0.004; anopsia: p = 0.011). No major complications including cerebrospinal fluid (CSF) leaks or wound-related complications were identified in the supraorbital craniotomy group, while the endonasal group had two CSF leaks requiring lumbar drain placement. Length of stay was shorter in the supraorbital group (3.4 vs. 6.1 days, p < 0.001).

Conclusion Anterior skull base meningiomas can be successfully managed by both supraorbital and endoscopic endonasal approaches. Both approaches provide excellent direct access to tumor in carefully selected patients and are safe and efficient, but patient factors and symptoms should dictate the approach selected.

Resection of Olfactory Groove Meningiomas Through Unilateral vs. Bilateral Approaches: A Systematic Review and Meta-Analysis

Introduction: Consensus is limited regarding optimal transcranial approaches (TCAs) for the surgical resection of olfactory groove meningiomas (OGMs). This systematic review and meta-analysis aims to examine operative and peri-operative outcomes of unilateral compared to bilateral TCAs for OGMs. Methods: Electronic databases were searched from inception until December 2019 for studies delineating TCAs for OGM patients. Patient demographics, pre-operative symptoms, surgical outcomes, and complications were evaluated and analyzed with a meta-analysis of proportions. Results: A total of 27 observational case series comparing 554 unilateral vs. 451 bilateral TCA patients were eligible for review. The weighted pooled incidence of gross total resection is 94.6% (95% CI, 90.7-97.5%; I ² = 59.0%; p = 0.001) for unilateral and 90.9% (95% CI, 85.6-95.4%; I ² = 58.1%; p = 0.003) for bilateral cohorts. Similarly, the incidence of OGM recurrence is 2.6% (95% CI, 0.4-6.0%; I ² = 53.1%; p = 0.012) and 4.7% (95% CI, 1.4-9.2%; I ² = 55.3%; p = 0.006), respectively. Differences in oncologic outcomes were not found to be statistically significant (p = 0.21 and 0.35, respectively). Statistically significant differences in complication rates in bilateral vs. unilateral TCA cohorts include meningitis (1.0 vs. 0.0%; p = 0.022) and mortality (3.2 vs. 0.2%; p = 0.007). Conclusions: While both cohorts have similar oncologic outcomes, bilateral TCA patients exhibit higher post-operative complication rates. This may be explained by underlying tumor characteristics necessitating more radical resection but may also indicate increased morbidity with bilateral approaches. However, evidence from more controlled, comparative studies is warranted to further support these findings.

Midline Meningiomas of the Anterior Skull Base: Surgical Outcomes and a Decision-Making Algorithm for Classic Skull Base Approaches

Simple Summary

Resectioning midline meningiomas of the anterior skull base such as olfactory groove, planum sphenoidale, or tuberculum sellae is challenging, and determining the appropriate approach is important. Based on our experience with midline meningiomas, we propose a decision algorithm for choosing suitable transcranial approaches. With dichotomizing classic skull bases approaches into median and lateral ones, we display that median approaches provide satisfactory results for olfactory groove meningiomas, whereas lateral approaches enable sufficient exposure of the visual apparatus for planum sphenoidale meningiomas or tuberculum sellae meningiomas. This manuscript aims to point out the sufficiency and feasibility of classic transcranial techniques.

Abstract

(1) Background: Midline meningiomas such as olfactory groove (OGMs), planum sphenoidale (PSMs), or tuberculum sellae meningiomas (TSMs) are challenging, and determining the appropriate approach is important. We propose a decision algorithm for choosing suitable transcranial approaches. (2) Methods: A retrospective chart review between 06/2007 and 01/2020. Clinical outcomes, radiographic findings, and postoperative complication rates were analyzed with respect to operative approaches. (3) Results: We included 88 patients in the analysis. Of these, 18.2% (16/88) underwent an interhemispheric approach, 72.7% (64/88) underwent a pterional/frontolateral/supraorbital approach, 2.3% (2/88) underwent a unilateral subfrontal approach, and 6.8% (6/88) underwent a bifrontal approach. All OGMs underwent median approaches, along with one PSM. All of the other PSMs and TSMs were resected via lateral approaches. The preoperative tumor volume was ∅20.2 ± 27.1 cm³. Median approaches had significantly higher tumor volume but also higher rates of Simpson I resection (75.0% vs. 34.4%). An improvement of visual deficits was observed in 34.1% (30/88). The adverse event rate was 17.0%. Median follow-up was 15.5 months (range 0–112 months). (4) Conclusions: Median approaches provides satisfying results for OGMs, lateral approaches enable sufficient exposure of the visual apparatus for PSMs and TSMs. In proposing a simple decision-making algorithm, the authors found that satisfactory outcomes can be achieved for midline meningiomas.

The interhemispheric fissure-surgical outcome of interhemispheric approaches

Exposure of the anterior skull base is challenging due to strategic structures. The interhemispheric approach (IHA) has turned out to be a feasible technique. We report our experience with IHAs in patients with extraaxial lesions (EAL). We performed a retrospective chart review at a tertiary neurosurgical center between April 2009 and March 2020. We included patients with resection of EAL through IHAs concentrating on surgical technique, complete resection rate, postoperative outcome, and complications. Seventy-four patients resected by an IHA were included: 49 (66.2%) frontal (FIA), nine (12.1%) parietooccipital (PIA), and 16 (21.6%) frontobasal IHAs (FBIAs). Median age at time of surgery was 59 years (range 16–88 years), 47 (63.5%) female and 27 (36.5%) male. Complete resection rate was 83.8% (FIA 89.8%, PIA 55.6%, FBIA 81.3%). Rate of new minor deficits was 17.6%, rate of major deficits 5.4%, total rate 23.0%. 51 (68.9%) WHO°I meningiomas, ten (13.5%) WHO°II meningiomas, two (2.7%) WHO°III meningiomas, nine (12.2%) metastases, one (1.4%) sarcoma, and one (1.4%) local adenocarcinoma were resected. Total complication rate was 27.0%. Rate of major complications requiring intervention was 9.6%. Mean follow-up was 34.2 (± 33.2) months. In patients with lesions of the interhemispheric fissure, overall morbidity and complications are comparatively high. Extensions of IHAs with potential even higher morbidity are not necessary though; we support the use of standardized IHAs. Our findings suggest regular usage of relatively feasible IHAs for a satisfying outcome. Invasive, complicated, or contralateral trajectories were not needed.

TRANS-FRONTAL SINUS APPROACH FOR OLFACTORY GROOVE MENINGIOMAS: A 19 YEAR EXPERIENCE

INTRODUCTION

Olfactory groove meningiomas (OGMs) account for 8-13 % of all intracranial meningiomas. The gold standard of treatment is generally surgery, however various approaches have been used and the literature is still uncertain about the superiority of one treatment over the others. The most debated techniques are traditional microscopic open approaches versus the endoscopic endonasal ones. The aim of this paper is to prove a valid surgical route that gathers the benefits of both endoscopic and transcranial routes.

METHODS

Fifty consecutive patients underwent trans-frontal sinus surgical removal of an OGM between January 2000 and January 2019 at the Neurosurgical Departments in Torino, Brescia and Legnano (Italy). The clinical features were collected in a database and compared with neuroimaging and outcomes. All patients were investigated with neuroimaging techniques. Clinical evaluations were performed 3-4 months and 1 year after surgery, together with neuroradiological follow-up.

RESULTS

All patients with OGM underwent Simpson grade I resection. The most common neurological symptom leading to neuroradiological evaluations were headaches (36 %), followed by behavioural changes (30 %), hyposmia/anosmia (12 %), visual impairments (6%) and focal deficits (6%). At 3-4 months follow-up 48 patients underwent a brain MRI (2 patients underwent a brain CT), and a complete resection was confirmed in 45 patients (94 %).

CONCLUSIONS

Despite different techniques and studies supported by good evidence, there is no consensus on the best surgical approach for OGMs. The data shown in this article suggests that the trans-frontal sinus approach is a valid alternative to an endoscopic approach and the classical transcranial routes, collecting benefits from both approaches.

Temporo-parietal muscle pedicle flap for reconstruction of the anterior skull base after resection of recurrent olfactory groove meningioma: a technical note

Reconstruction becomes the main issue in surgery for tumours penetrating the anterior skull base because it faces the nasal cavity. Vascularized flaps are desirable for preventing infection, but in re-opening surgery, tissue availability is limited. We report a case of recurrent olfactory groove meningioma in which the anterior skull base defect was reconstructed using a temporo-parietal muscle (TPM) pedicle flap. A 65-year-old woman presented with recurrent olfactory groove meningioma penetrating the anterior skull base. Because the frontal pericranium had been used in the initial surgery, the temporal fascia was harvested with a TPM pedicle flap from behind the initial bicoronal incision. After removal of the tumour, the pedicle flap reached the sphenoid planum easily and was sutured to the surrounding structures. The fascia lata was sutured as an inlay. The postoperative course was uneventful, and no cerebrospinal fluid leakage was observed. In re-opening surgery, a TPM pedicle flap can be an option for reconstruction of the anterior skull base.

Endoscopic endonasal versus transcranial approach to resection of olfactory groove meningiomas: a systematic review

Despite the increasing utility of the endoscopic endonasal approach (EEA) for management of anterior skull base (ASB) pathologies, the optimal treatment strategy for olfactory groove meningiomas (OGM) remains unclear. This project sought to systematically compare outcomes of EEA management with conventional transcranial approach (TCA) for the treatment of OGMs. A systematic review was performed to identify studies that compared outcomes following EEA and TCA for OGMs. Data extracted from each study included gross total resection (GTR), incidence of cerebrospinal fluid (CSF) leaks, and post-operative complications including anosmia. The results of the search yielded 5 studies which met the criteria for inclusion and analysis. All studies compared TCA (n = 922) with EEA (n = 141) outcomes for OGMs. Overall, the rate of gross total resection (GTR) was lower among the endoscopic group (70.9%) relative to the transcranial group (91.5%). The rate of post-operative CSF leak was 6.3% vs. 25.5% for the transcranial and endoscopic groups, respectively. Post-operative anosmia was higher for patients undergoing EEA (95.9%) compared with patients in the transcranial group (37.4%). In this analysis, EEA was associated with a lower rate of GTR and higher incidences of CSF leaks and post-operative anosmia. However, with increasing surgeon familiarity of the endoscopic anatomy and technique for managing ASB pathologies, a nuanced approach may be used to minimize patient morbidity and widen the spectrum of skull base surgery.

Surgical Outcomes of Endoscopic Versus Open Resection for Primary Sinonasal Malignancy: A Meta-analysis

Background

Endoscopic resection (ER) for uncommon sinonasal malignancies (SNMs) has been reported to confer superior surgical outcomes compared to open resection (OR) based on indirect comparisons of limited evidence.

Objective

The aim of this study was to pool all direct comparative studies in the literature to validate this potential superior association.

Methods

Systematic searches of 7 electronic databases from their inception to April 2019 were conducted following Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. There were 1001 articles identified for screening. Outcomes of interest were pooled as risk ratios (RRs) and mean difference (MD) and analyzed using a random-effects model.

Results

There were 10 studies included in this meta-analysis, with 900 SNM patients in total where ER and OR were utilized in 399 (44%) and 501 (56%) cases, respectively. Compared to OR, random-effects (RE) modeling indicated ER resulted in statistically comparable complications (RR = 0.68; P-effect = .12) and recurrence (RR = 0.84; P-effect = .35). ER was associated with significantly shorter length of stay (LOS) compared to OR (MD = −2.9 days; P-effect <.01).

Conclusions

The use of ER to manage SNM was associated with significantly favorable reduction in LOS compared to OR. However, with respect to other surgical outcomes and recurrence, the current literature does not indicate either ER or OR as statistically superior. Therefore, until greater validation of these associations can be proven, expectations that ER for SNMs confers superior surgical outcomes compared to OR should be tempered.

Perioperative olfactory dysfunction in patients with meningiomas of the anteromedial skull base

Olfactory dysfunction represents a main symptom in olfactory groove meningiomas (OGM). Besides this, olfactory function has been sparsely investigated in patients suffering from supratentorial meningiomas. Here, the authors explore pre- and postoperative variables associated with olfactory dysfunction in supratentorial meningioma patients. This is a retrospective study on supratentorial meningioma patients who underwent meningioma resection between January 2015 and January 2016. Preoperative and postoperative olfactory performance was quantified using a lateralized sniffin' stick odor identification test. Meningiomas affecting the olfactory system (n = 23) were compared to meningiomas in other locations among the control group (n = 40). Meningiomas that affected the olfactory system had odds of 3.6 and 3.7 in being associated with ipsilateral (lesional) and bilateral anosmia, respectively. Subgroup analysis revealed that meningiomas causing a midline shift across the frontal base and older age represented risk factors for preoperative anosmia. The odds of experiencing acquired postoperative ipsilateral anosmia were significantly increased in olfactory system affecting meningiomas (OR 11.1). Subgroup analysis highlighted OGMs to represent the predominant location associated with deterioration. General surgical complications predisposed patients to loss of contralateral (OR 12.3) and bilateral olfactory function (OR 27.8). Older age and meningiomas causing a midline shift across the frontal base predispose patients to preoperative olfactory dysfunction. Resection of OGMs and surgical complications are risk factors for postoperative olfactory deterioration to anosmia. Likely, olfactory dysfunction is underrecognized even in OGMs. In OGM surgery, however, preoperative lateralized testing might be critical to selecting an appropriate surgical route to preserve olfactory function. Clin. Anat. 32:524-533, 2019. © 2019 Wiley Periodicals, Inc.

Small Extended Bifrontal Approach for Midline Anterior Skull Base Meningiomas: Our Experience with 54 Consecutive Patients

OBJECTIVE

To describe the technique of a small extended bifrontal approach and review the clinical outcome of patients with midline anterior skull base (MASB) meningiomas treated using this technique.

METHODS

The small extended bifrontal craniotomy extends inferiorly to the nasofrontal suture without entering the orbit, superiorly 3 cm above the supraorbital rim, and laterally 3 cm to the midline on both sides. A review of a prospectively acquired database was performed of 54 consecutive patients with MASB meningiomas who underwent this craniotomy.

RESULTS

Twenty-nine patients with olfactory groove meningiomas, 2 with planum sphenoidale meningiomas (PSMs), and 23 with tuberculum sellae meningiomas (TSMs) were treated using this technique. Gross total resection was achieved in all patients. Of 29 patients with olfactory groove meningiomas, 12 (41.4%) had normal olfaction at presentation and 8 had preservation of olfaction postoperatively. Of 25 patients with TSMs/PSMs, 23 (92.0%) had preoperative visual impairment, with 13 showing improved vision (56.5%), 8 unchanging (34.8%), and 2 deteriorating (8.7%) after surgery. The most common complications were anosmia and hyposmia, which occurred in 5 patients (20.0%) and 3 patients (12.0%) with TSMs/PSMs, respectively. No mortality was reported. There was no recurrence in all patients after a mean follow-up of 39.5 months (range, 16-64 months).

CONCLUSIONS

The small extended bifrontal approach is a safe and effective technique for resection of MASB meningiomas, which provides adequate surgical exposure with less approach-related morbidity. It is an excellent alternative for surgeons who favor the bifrontal approach and its extended variations.

Olfactory groove and tuberculum sellae meningioma resection by endoscopic endonasal approach versus transcranial approach: A systematic review and meta-analysis of comparative studies

Intracranial meningiomas such as olfactory groove meningioma (OGM) and tuberculum sellae meningioma (TSM) arising at the anterior skull base are amenable to surgical resection. Traditionally, this has been achieved by transcranial approaches (TCAs), however, there has been an evolution in an endoscopic endonasal approach (EEA) within recent years. The aim of this systematic review and meta-analysis was to determine if the EEA was superior to the TCA in managing these anterior skull base meningioma based on comparative studies only, and highlight the limitations of the current literature. Searches of seven electronic databases from inception to April 2018 were conducted following Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. There were 1479 articles identified for screening. Data were extracted and analyzed using meta-analysis of proportions. A total of 10 comparative studies satisfied criteria for inclusions. Resection by the EEA resulted in significantly less likelihood of worse vision (OR, 0.318; p = 0.039) when compared to TCA in OGM. However, EEA resulted also in significantly greater likelihoods of olfactory loss in OGM (OR, 4.511; p = 0.038) and TSM (OR, 3.075; p = 0.017), and CSF leak (OR, 3.854; p = 0.013) in TSM. In terms of surgical and prognosis outcomes, there was no statistically significant trend in favor of either approach in OGM or TSM. The EEA appears to confer a different postoperative complication profile when compared to the TCA in resecting OGM vs TSM which validates previous case-series comparisons. There is a need for longer-term studies that are larger, prospective, randomized in order to fully elucidate efficacy given slow tendency for progression of meningioma in order to develop a more rigorous approach selection algorithm.

The Endoscopic Endonasal Management of Anterior Skull Base Meningiomas

Introduction  The endoscopic endonasal approach (EEA) might seem an "unnatural" route for intradural lesions such as meningiomas. The aim of this study is to critically revise our management of anterior skull base meningiomas to consider, in what cases it may be advantageous. Material and Methods  Each consecutive case of anterior skull base meningioma operated on through an EEA or combined endoscopic-transcranial approach at our institution, between 2003 and 2017, have been included. Tumors were classified on the basis of their location and intra or extracranial extension. Follow-up consisted of an MRI (magnetic resonance imaging) and a clinical examination 3 months after the surgery and then repeated annually. Results  Fifty-seven patients were included. The most common location was the tuberculum sellae (62%), followed by olfactory groove (14%), planum sphenoidale (12%), and frontal sinus (12%). Among these, 65% were intracranial, 7% were extracranial, and 28% both intra and extracranial. Radical removal was achieved in 44 cases (77%). Complications consisted in 10 CSF (cerebrospinal fluid) leaks (17.6%), 1 overpacking (1.7%), and 1 asymptomatic brain ischemia (1.7%). Visual acuity and campimetric deficits improved respectively in 67 and 76% of patients. Recurrence rate was of 14%. Conclusions  EEA presents many advantages in selected cases of anterior skull base meningioma. However, it is hampered by the relevant risk of CSF leak. We consider that it could be advantageous for planum/tuberculum sellae tumors. Conversely, for olfactory groove or frontal sinus meningiomas, it can be indicated for tumors with extracranial extension, while its role is still debatable for purely intracranial forms as considering our surgical results, it could be advantageous for midline planum/tuberculum sellae tumors. Conversely, it can be of first choice for olfactory groove or frontal sinus meningiomas with extracranial extension, while its role for purely intracranial forms is still debatable.

Training the skull base surgeon of the future: a comprehensive approach

The tremendous advances in endoscopic skull base surgery added a new set of intricate less invasive approaches to the neurosurgical armamentarium. The new generations of neurosurgeons face the challenge of adopting the ever-changing technology and quickly learning modern surgical techniques beyond the traditional neurosurgery comfort zone. The future skull base surgeon must be well trained and knowledgeable in all surgical portals to the skull base in order to select the safest, least invasive, most direct approach that offers the optimum exposure to handle a complex skull base pathology. The multi-portal/corridor philosophy is often adopted in order to achieve superior surgical and clinical outcomes. Neurosurgeons need to consider such an approach when appropriate as it may offer a superior outcome while minimizing the morbidity associated with large exposures.