Olfactory Groove Meningiomas: Clinical Outcome and Recurrence Rates after Tumor Removal Through the Frontolateral and Bifrontal Approach

A Cadaveric Feasibility Study of the Biportal Endoscopic Transfrontal Sinus Approach: A Minimally Invasive Approach to the Anterior Cranial Fossa

BACKGROUND AND OBJECTIVES

The trans-sinus transglabellar and bifrontal approaches offer direct access to the anterior cranial fossa. However, these approaches present potential drawbacks. We propose the biportal endoscopic transfrontal sinus (BETS) approach, adapting endoscopic endonasal approach (EEA) techniques for minimally invasive access to the anterior fossa, reducing tissue manipulation, venous sacrifice, and brain retraction.

METHODS

Six formalin specimens were used. BETS approach involves 2 incisions over the medial aspect of both eyebrows from the supraorbital notch to the medial end of the eyebrow. A unilateral pedicled pericranial flap is harvested. A craniotomy through the anterior table of the frontal sinus (FS) and a separate craniotomy through the posterior table are performed. Two variants of the approach (preservative vs cranialization) are described for opening and reconstruction of the FS based on the desired pathology to access. Bone flap replacement can be performed with titanium plates and filling of the external table defect with bone cement.

RESULTS

Like in EEA, this approach provides access for endoscope and multiple working instruments to be used simultaneously. The approach allows wide access to the anterior cranial fossa, subfrontal, and interhemispheric corridors, all the way up to the suprachiasmatic corridor and through the lamina terminalis to the third ventricle. BETS provides direct access to the anterior fossa, minimizing the level of frontal lobe retraction and providing potentially less tissue disruption and improved cosmesis. Cerebrospinal fluid fistula risk remains one of the major concerns as the narrow corridor limits achieving a watertight closure which can be mitigated with a pedicled flap. Mucocele risk is minimized with full cranialization or reconstruction of the FS.

CONCLUSION

The BETS approach is a minimally invasive approach that translates the concepts of EEA to the FS. It allows excellent access to the anterior cranial fossa structures with minimal frontal lobe retraction.

Endoscopic-Assisted Microsurgical Meningioma Resection in the Skull Base via Minicraniotomy: Is There a Difference in Radicality and Outcome between Anterior Skull Base and Posterior Fossa?

Background: Keyhole-based approaches are being explored for skull base tumor surgery; aiming for reduced complications while maintaining resection success rates. This study evaluates skull base meningiomas resected using an endoscopic-assisted microsurgical keyhole approach, comparing outcomes with standard procedures. Methods: Between 2013 and 2019; 71 out of 89 patients were treated using an endoscopic-assisted microsurgical procedure. A total of 42 meningiomas were localized at the anterior skull base and 29 in the posterior fossa. The surgical techniques and use of an endoscope were analyzed and compared in terms of complications, surgical radicality, outcome, and recurrences in the patients' follow-up. Results: The two different cohorts yielded similar rates of GTR (anterior skull base: 80% versus posterior fossa: 82%). The complication rate was 31% for the posterior fossa and 16% for the anterior skull base. An endoscope was used in 79% of all cases. Tumor remnants were detected by means of endoscopic visualization in 58.6% of posterior fossa and 33% of anterior skull base meningiomas. The statistical analysis revealed significantly higher benefits from endoscope use in the posterior fossa cohort (p < 0.05). Conclusions: The results revealed that endoscopy was beneficial in both locations. The identification of remnant tumor tissue and the benefit of endoscopy were clearly higher in the posterior fossa. Endoscopic assistance is a very helpful tool for increasing radicality, providing a better anatomical overview during surgery, and better identifying remnant tumor tissue in skull base meningioma surgery.

Surgical Morbidity in Relation to the Surgical Approach for Olfactory Groove Meningiomas-A Pooled Analysis of 1016 Patients and Proposal of a New Reporting System

Background: There is currently no consensus in the field regarding whether a frontal or lateral approach is superior for microsurgical resection of olfactory groove meningiomas (OGM). Due to the lack of uniformity in classifying lesions and inherent differences in reporting outcomes after varying operative approaches, the best practice for approaching these lesions is yet to be determined. Objective: This study aimed to assess various surgical approaches undertaken for OGMs, investigate procedural aspects influencing the extent of resection, and analyze the respective complication rate associated with each approach. We performed a comprehensive literature review of presenting signs and symptoms in OGM patients, their surgical management, and the reported surgical outcomes. To address the lack of uniform data reporting across studies and to take more recent translational studies into account, we developed a new classification system for OGMs that can remedy the existing deficiencies in comparability of reporting. Methods: We conducted a PRISMA-guided literature search for surgical reports on OGMs published in the MRI era using broad search terms such as 'olfactory groove meningioma' and 'surgery', which yielded 20,672 results. After title screening and removal of duplicates, we assessed 871 studies on the specific surgical management of olfactory groove meningiomas. Following the application of exclusion criteria and abstract screening, a set of 27 studies was chosen for the final analysis of a pooled cohort of these reported patient outcomes. Results: The final twenty-seven studies included in our in-depth analysis identified a total of 1016 individual patients who underwent open microsurgical resection of OGMs. The approaches used included: pterional/unilateral, bifrontal with variations, and anterior interhemispheric approaches. Across all studies, gross total resection (Simpson Grades I or II) was achieved in 91.4% of cases, and subtotal resection (Grades III and IV) was reported in 8.6% of cases. A cumulative twenty-seven percent of surgical OGM patients sustained some form of complications. Minor issues accounted for 22.2% (CSF leak, seizures, infection, transient cranial nerve palsies, hydrocephalus), whereas major issues comprised 4.7% (hemorrhage, ischemic infarct, malignant cerebral edema). We then examined the correlation between these complications and the surgical approach chosen. Among pooled cohort of 426 patients who underwent unilateral approaches, 14% experienced minor complications, and 2.1% experienced major complications. For the mixed cohort of 410 patients who underwent bifrontal approaches, 24.6% experienced minor complications, and 7% experienced major complications. Conclusions: Unilateral approaches appear to have lower complication rates for the resection of OGMs compared to bilateral approaches. However, the extent of resection is not uniformly reported, making it difficult to identify differences. The use of an improved preoperative classification and scoring system can help establish a more coherent system to select the most suitable approach and to uniformly report surgical outcomes, such as EOR and complication rates specific to a given OGM and its surgical approach.

The Evolution of Endoscopic Endonasal Approach for Olfactory Groove Meningiomas

BACKGROUND

There is controversy over the choice of optimal approach for olfactory groove meningiomas (OGM). The endoscopic endonasal approach (EEA) is one of the most recently described corridors, which provides direct access to the tumor base.

OBJECTIVE

To detail the evolution of the endoscopic endonasal technique over the past 2 decades and demonstrate the impact of this evolution on patient outcomes.

METHODS

This is a retrospective study based on a prospectively maintained database of consecutive cases of OGM operated on at our institution via EEA. For analysis, the whole cohort has been divided into 3 equal "eras" according to the time period during which the surgery happened, creating early, middle, and contemporary groups.

RESULTS

Seventy-five patients were included, 25 in each group. The rate of postoperative cerebrospinal fluid leak significantly decreased over time (28%, 32%, and 8% in the early, middle, and contemporary groups, respectively, P = .020). The rate of postoperative encephalomalacia was significantly lower in more recent groups (24%, 16%, and 0% in the early, middle, and contemporary groups, respectively, P = .029), as was the time to resolution of postoperative brain edema (103.9 months, 87.3 months, and 16.8 months in the early, middle, and contemporary groups, respectively, P = .020).

CONCLUSION

The endoscopic endonasal approach for OGM significantly evolved over time, achieving lower cerebrospinal fluid leak rates while providing a high rate of Simpson grade 1 resection. Technical improvements minimized the frontal lobe impact. Current data support EEA as a safe and effective corridor to treat OGM.

Lateral supraorbital approach for resection of large and giant olfactory groove meningiomas: a single center experience

BACKGROUND

The lateral supraorbital approach (LSO) provides an optimal access corridor for various skull bases lesions, including olfactory groove meningiomas (OGMs). The aim of this study is to describe the authors' experience with the management of large and giant OGMs utilizing the LSO approach and describe the technical nuances of the procedure.

METHODS

A retrospective review of seven patients with large and giant OGMs managed with the LSO approach between 2013 and 2019 was performed. Radiographic and clinical data were recorded and analyzed.

RESULTS

Seven patients with large and giant OGMs underwent surgical resection via the LSO approach. Six patients were female, with a median age of 56 years. Patients commonly presented with altered mentation, anosmia, and headaches. The average tumor volume was 120.6 ± 64.7 cm³ with five cases of vascular encasement. Simpson grade II resection was achieved in four patients while Simpson grade IV resection was achieved in three patients. The median length of stay was 2.0 days. The median preoperative Karnofsky Performance Scale (KPS) score was 70, improving to 100 at last postoperative follow-up visit. Two complications were encountered in the form of postoperative cerebrospinal fluid leak in one patient and a transient diplopia in another patient. Tumor recurrence/progression was identified in two patients during a median follow-up time of 65.5 months. Both cases have been managed with adjuvant radiosurgery.

CONCLUSION

The LSO approach is a safe and effective minimally invasive transcranial corridor for the management of OGMs that should be part of the armamentarium of skull base neurosurgeons.

Post-traumatic intra-orbital meningoencephalocele in adults: technical note on a rare entity and review of the literature

Post-traumatic orbital meningoencephaloceles related to orbital roof fractures are a challenging clinical entity because of their rarity and difficult differential diagnosis. We report a case of post-traumatic intra-orbital meningoencephalocele in a 69-year-old man, secondary to a likely trapdoor mechanism, treated with a modified one-piece orbitozygomatic craniotomy. We also performed an extensive literature review of traumatic Intra-Orbital Encephalocele related to Orbital Roof Fracture focused on adult patients on electronic databases including Scopus, MEDLINE/PubMed, and Google Scholar. Patient well recovered after surgery with immediate exophthalmos resolution and discharged without visual or neurological deficits. The literature review included 22 papers with a total of 28 patients: 22 males (78.6%) and 6 females (21.4%), with a median age of 34.7 years. Twenty-six patients (92.9%) reported ocular injuries, with associated intracranial complications in 16 cases (61.5%). Twenty-seven patients (96.4%) were surgically treated, 18 of those underwent unilateral or bilateral frontal approach. Most orbital roof fractures can be managed nanoperatively if asymptomatic. Indeed, when the intra-orbital volume decreases, for example due to an encephalocele, the intra-orbital pressure could increase and determine an orbital compartment syndrome. In our case, we performed a one-piece modified orbitozygomatic approach, which has several advantages in comparison to the frequent unilateral or bilateral frontal craniotomy like the better exposure of the brain and orbit and a minimum brain retraction.

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.

Quantitative Anatomic Comparison of Endoscopic Transnasal and Microsurgical Transcranial Approaches to the Anterior Cranial Fossa

BACKGROUND

Several microsurgical transcranial approaches (MTAs) and endoscopic transnasal approaches (EEAs) to the anterior cranial fossa (ACF) have been described.

OBJECTIVE

To provide a preclinical, quantitative, anatomic, comparative analysis of surgical approaches to the ACF.

METHODS

Five alcohol-fixed specimens underwent high-resolution computed tomography. The following approaches were performed on each specimen: EEAs (transcribriform, transtuberculum, and transplanum), anterior MTAs (transfrontal sinus interhemispheric, frontobasal interhemispheric, and subfrontal with unilateral and bilateral frontal craniotomy), and anterolateral MTAs (supraorbital, minipterional, pterional, and frontotemporal orbitozygomatic approach). An optic neuronavigation system and dedicated software (ApproachViewer, part of GTx-Eyes II-UHN) were used to quantify the working volume of each approach and extrapolate the exposure of different ACF regions. Mixed linear models with random intercepts were used for statistical analyses.

RESULTS

EEAs offer a large and direct route to the midline region of ACF, whose most anterior structures (ie, crista galli, cribriform plate, and ethmoidal roof) are also well exposed by anterior MTAs, whereas deeper ones (ie, planum sphenoidale and tuberculum sellae) are also well exposed by anterolateral MTAs. The orbital roof region is exposed by both anterolateral and lateral MTAs. The posterolateral region (ie, sphenoid wing and optic canal) is well exposed by anterolateral MTAs.

CONCLUSION

Anterior and anterolateral MTAs play a pivotal role in the exposure of most anterior and posterolateral ACF regions, respectively, whereas midline regions are well exposed by EEAs. Furthermore, certain anterolateral approaches may be most useful when involvement of the optic canal and nerves involvement are suspected.

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.

Two-step staged resection of giant olfactory groove meningiomas

Background

The surgical treatment of giant olfactory groove meningiomas (OGMs) with marked perilesional brain oedema is still a surgical challenge. After tumour resection, increase of brain oedema may occur causing dramatic neurological deterioration and even death of the patient. The objective of this paper is to describe surgical features of a two-step staged resection of these tumours performed to counter increase of postoperative brain oedema.

Methods

This two-step staged resection procedure was carried out in a consecutive series of 19 patients harbouring giant OGMs. As first step, a bifrontal craniectomy was performed followed by a right-sided interhemispherical approach. About 80% of the tumour mass was resected leaving behind a shell-shaped tumour remnant. In the second step, carried out after the patients’ recovery from the first surgery and decline of oedema, the remaining part of the tumour was removed completely followed by duro- and cranioplasty.

Results

Ten patients recovered quickly from first surgery and the second operation was performed after a mean of 12.4 days. In eight patients, the second operation was carried out later between day 25 and 68 due to surgery-related complications, development of a trigeminal zoster, or to a persisting frontal brain oedema. Mean follow-up was 49.3 months and all but one patient had a good outcome regardless of surgery-related complications.

Conclusions

Our results suggest that a two-step staged resection of giant OGMs minimizes the increase of postoperative brain oedema as far as possible and translates into lower morbidity and mortality.

Olfactory groove meningioma with a 10-year history of smell loss and olfactory recovery after surgery

A rare cause of olfactory impairment is olfactory groove meningiomas with insidious onset of non-specific symptoms like headache, olfactory dysfunction, psychiatric symptoms such as depression, personality changes, declining cognitive function, visual disturbances or seizures. A common complication of surgery is loss of olfactory function. Still, the preservation of olfactory function should be attempted as olfactory loss often has a severe negative impact on quality of life. This report describes a woman with an olfactory groove meningioma and a 10-year history of olfactory impairment. It includes preoperatively and postoperatively extended olfactory testing, a neurosurgical approach to preserve the olfactory function and postoperative olfactory rehabilitation. After rehabilitation, the patient regained a normal olfactory function, even though the right-sided olfactory nerve could not be preserved during surgery. The case demonstrates the importance of performing neuroimaging in selected patients with olfactory loss and a method for preserving and potentially improving postoperative olfactory function.

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.

Child Abuse: The Consequence of an Undiagnosed Giant Olfactory Groove Meningioma?

Olfactory groove meningiomas are slow-growing tumors that manifest with headaches, changes in vision, and personality changes. The anatomic location of these tumors makes psychiatric disturbances more common early in the stage of tumors than focal neurological deficits. The case study here describes a unique instance of an undiagnosed giant olfactory groove meningioma in a young mother who was charged with a felony of aggravated child abuse for the death of her toddler daughter. The patient underwent gross tumor resection and radiation therapy, which halted the visual decline, resolved the frontal headaches, and the patient showed improved mood. In this patient, the insidious onset of personality changes without obvious focal neurologic deficits until late as well as a history of depression likely contributed to the delayed diagnosis. Failure to notice these initial behavioral manifestations in these patients allows for further psychiatric and cognitive decline, which can result in devastating social consequences.

Meningiomas of the Planum Sphenoidale and Tuberculum Sella

Patients with meningiomas of the planum sphenoidale and tuberculum sella often present with insidious vision loss in one or both eyes as the only sign or symptom of their disease, although other sensory, oculomotor, and even endocrine abnormalities may be seen in a minority of cases. Incidentally discovered tumors also are common, as patients may undergo neuroimaging for unrelated symptoms or events. Depending on the size and orientation of the tumor, central vision loss from optic nerve compression may be a later sign, and loss of peripheral vision in one or both eyes may not be recognized until it has progressed to areas closer to fixation. A thorough neuroophthalmologic assessment including visual field testing will help to define the extent of optic pathway involvement. Both fundus examination and optical coherence tomography of the retinal nerve fiber layer and macular ganglion cell complex will aid in determining prognosis after treatment of the tumor. Orbital surgery rarely is indicated as primary therapy for meningiomas in this location, and surgical resection or debulking is usually pursued before consideration is given to radiation therapy. Because of the long-term risk of residual tumor growth or recurrence, neuroophthalmic surveillance along with serial neuroimaging is required for years after tumor resection and/or radiation therapy.

What's that smell? A pictorial review of the olfactory pathways and imaging assessment of the myriad pathologies that can affect them

The olfactory pathway is composed of peripheral sinonasal and central sensorineural components. The wide variety of different pathologies that can affect the olfactory pathway reflect this complex anatomical relationship. Localising olfactory pathology can present a challenge to the reporting radiologist. This imaging review will illustrate the normal anatomy of the olfactory system and describe a systematic approach to considering olfactory dysfunction. Key concepts in image interpretation will be demonstrated using examples of olfactory pathway pathologies.

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.

Single surgeon experience with minimally invasive supraorbital craniotomy versus bifrontal craniotomy for anterior skull base meningiomas

Background:

Anterior skull base meningiomas (ASBMs) account for about 10% of meningiomas. Bifrontal craniotomy (BFC) represents the traditional transcranial approach to accessing meningiomas in these locations. Supraorbital craniotomy (SOC) provides a minimally invasive subfrontal corridor in select patients. Here, we present our series of ASBM accessed by SOC and BFC by a single surgeon to review decision-making and compare outcomes in both techniques.

Methods:

Thirty-three patients were identified with ASBM. Age, tumor characteristics, presenting symptoms, postoperative complications, and outcomes were analyzed.

Results:

Bifrontal and SOC were performed in 13 and 20 patients, respectively. Mean follow-up time was 98.4 months. Patients undergoing SOC had smaller tumor size, located farther from the posterior table of frontal sinus, had less peritumoral edema, and decreased length of stay compared to patients undergoing BFC. Extent of resection was slightly better with BFC (99.8%) compared to SOC (91.8%), although this difference did not reach statistical significance. Recurrence-free survival and rate of re-do surgeries were not different between two groups. BFC was associated with higher rates of postoperative encephalomalacia.

Conclusion:

SOC provides an excellent surgical option for ASBMs providing comparable extent of resection, minimal manipulation of brain, and excellent cosmetic outcomes for patients. The patient selection is key to maximize the benefits from this approach.

An Illustrative Review of Common Modern Craniotomies

Craniotomy, or a surgical opening into the skull, has been observed as early as Paleolithic and Neolithic periods. Early craniotomies carried great morbidity and mortality and standardized during the 20th century, improving surgical outcomes. The simultaneous evolution of medical imaging and stereotactic navigation systems has allowed imaging to correlate findings with surgical approaches, further optimizing patient safety. We review the history of craniotomy and provide an imaging review of the most common craniotomy approaches.

Cognitive Changes in a Commercial Pilot Secondary to an Olfactory Meningioma

BACKGROUND: Olfactory meningiomas are typically benign, slow-growing intracranial tumors with subtle presentations that result in delayed diagnosis. To date, only a few published reports describe meningiomas in airmen. None specifically mention olfactory meningiomas or detail the associated presence of cognitive impairment.CASE REPORT: This was a 55-yr-old commercial pilot with over 20 yr of flight experience who presented for a fitness-for-duty evaluation due to alarming performance at work and neurocognitive concerns. On examination, the patient had an odd affect and anosmia. Imaging showed a large, frontal, midline intracranial mass consistent with an olfactory meningioma.DISCUSSION: Fitness-for-duty cases are often challenging and even more so when neurocognition is called into question. Symptoms may be subtle and gradual in onset, making recognition and diagnosis difficult. Dementia, alcohol or substance misuse/abuse, and psychiatric diagnoses are often the first conditions considered when evaluating new cognitive impairment in a pilot. This case highlights the importance of keeping a broad differential, including intracranial masses, conducting a thorough neurological examination, and the judicious use of brain imaging.Hong M, Kreykes AJ. Cognitive changes in a commercial pilot secondary to an olfactory meningioma. Aerosp Med Hum Perform. 2020; 91(12):966969.

Endoscopic endonasal surgery for anterior cranial fossa meningiomas

Meningiomas along the anterior skull base arise from the midline but have historically been resected via open cranial approaches with lateral to medial trajectories. The endoscopic endonasal approach (EEA) offers a direct, inferomedial approach which has demonstrated several superior qualities for their resection. These meningiomas include tuberculum sellae, planum sphenoidale, and olfactory groove meningiomas. While early gross total resection (GTR) was lower than open approaches, EEA has currently achieved comparable rates of GTR and significantly improved postoperative visual outcomes. Rate of cerebrospinal fluid (CSF) leak was one of the early complicating features preventing widespread use of EEA. However, CSF leak rates have dramatically fallen into a tolerable range with introduction of the vascularized nasoseptal flap. Olfactory groove meningiomas often present with anosmia which is persistent after endonasal approach. Rates of other complications have proven similar between EEA and open approaches and include: vascular injury, infection, morbidity, and mortality. With the appropriate team and experience, EEA for anterior skull base meningiomas is increasingly becoming the standard for resection of these lesions. However, there are certain anatomic considerations, patient features, and other aspects which may favor the open approach over EEA, and vice versa; these must be carefully and judiciously evaluated preoperatively. Overall, resection and recurrence rates are comparable, complication rates fall within a very acceptable range, and patients experience superior cosmesis and improved visual outcome with this approach.

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.

Anterior skull base olfactory tumours, which is what? A case report and review

Intracranial schwannomas not originating from cranial nerves are rare. In this paper, we report a case of a 50-year-old male who presented with worsening headaches, diplopia and nausea over two years. Radiological imaging revealed a large tumour arising from the olfactory groove region with a preoperative diagnosis of olfactory groove meningioma (OGM). Intraoperatively, the tumour originated from the region of the attachment of the falx to the crista galli. The patient recovered without complication and histopathology reported an unexpected diagnosis of WHO Grade 1 schwannoma. However, as olfactory groove schwannomas (OGSs) cannot be distinguished from olfactory ensheathing cell tumours (OECTs), it is possible that the tumour could have been either an OGS or an OECT. Distinguishing between OGSs, OECTs and OGMs preoperatively is difficult. OGMs exhibit distinct histopathological features from OGSs/OECTs, however, OGSs and OECTs currently cannot be distinguished from each other. Here, we review the literature to discuss the differentiating features and cellular origins of these three tumours.

Results of Transcranial Resection of Olfactory Groove Meningiomas in Relation to Imaging-Based Case Selection Criteria for the Endoscopic Approach

BACKGROUND

Endoscopic endonasal surgery (EES) is increasingly used for olfactory groove meningiomas (OGMs). The role of EES for large (≥4 cm) or complex OGMs is debated. Specific imaging features have been reported to affect the degree of gross total resection (GTR) and complications following EES for OGMs. The influence of these factors on transcranial resection (TCR) is unknown.

OBJECTIVE

To examine the impact of specific imaging features on outcome following TCR to provide a standard for large and endoscopically less favorable OGMs against which endoscopic outcomes can be compared.

METHODS

Retrospective study of patients undergoing TCR for OGMs 2002 to 2016.

RESULTS

Fifty patients (mean age 62.1 yr, mean maximum tumor diameter 5.04 cm and average tumor volume of 48.8 cm3) were studied. Simpson grade 1 and 2 resections were achieved in 80% and 12%, respectively. A favorable functional outcome (modified Rankin Scale [mRS] 0-2) was attained in 86%. The degree of resection, mRS, mortality (4%), recurrence (6%), infection (8%), and cerebrospinal fluid leak requiring intervention (12%) were not associated with tumor calcification, absence of cortical cuff, T2 hyperintensity, tumor configuration, tumor extension beyond midpoint of superior orbital roof, or extension to posterior wall of frontal sinus. There was no difference in resection rates but a trend towards greater complications between 3 arbitrarily divided groups of large meningiomas of increasing complexity based on extensive extension or vascular adherence.

CONCLUSION

Favorable outcomes can be achieved with TCR for large and complex OGMs Factors that may preclude endoscopic resection do not negatively affect outcome following TCR.

Cost-effectiveness of endoscopic endonasal vs transcranial approaches for olfactory groove meningioma

BACKGROUND

Endoscopic endonasal approaches (EEAs) have been adopted as an alternative to standard transcranial approaches for olfactory groove meningiomas (OGMs). However, the relative cost-effectiveness remains controversial.

METHODS

Cost-utility analysis from a societal perspective comparing EEA vs transcranial approaches for OGM was used in this study. Surgical treatment was modeled using decision analysis, and a Markov model was adopted over a 20-year horizon. Parameters were obtained from literature review. Costs were expressed in 2017 Canadian dollars.

RESULTS

In the base case, EEA was cost-effective compared with transcranial surgery with an incremental cost-effectiveness ratio of $33 523 ($30 475 USD)/QALY. There was a 55% likelihood that EEA was cost-effective at a willingness-to-pay of $50 000/QALY. EEA remained cost-effective at a cerebrospinal fluid leak rate below 60%, gross total resection rate above 25%, and base cost less than $66 174 ($60 158 USD).

CONCLUSION

EEA may be a cost-effective alternative to transcranial approaches for selected OGM.

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.

Wedge Resection of the Falx to Clip a Distal Anterior Cerebral Artery Aneurysm

BACKGROUND

The unilateral anterior interhemispheric approach has been widely used for distal anterior cerebral artery (DACA) aneurysms. However, there are some drawbacks of this approach because of the narrow operative field, including possible brain traction injury, bridging vein injury, and inadequate exposure of the aneurysm. Here, we report a case of a DACA aneurysm covered by the falx that could not be totally exposed with the unilateral interhemispheric approach. We successfully obtained a wide view with wedge resection of the falx, avoiding excessive brain traction and division of the superior sagittal sinus.

CASE DESCRIPTION

A 76-year-old woman with a 6-mm unruptured DACA aneurysm underwent a unilateral craniotomy with the anterior interhemispheric approach. In the operative field, the aneurysm was found at the midline, just below the falx. The aneurysm was covered by the falx and could not be completely exposed with the usual brain retraction. Therefore, we performed wedge resection of the falx, thus obtaining sufficient surgical field and totally exposing the aneurysm. We were then able to apply the clip successfully. Postoperative brain computed tomography angiography showed no remnant aneurysm sac or complications of falx resection or brain retraction, such as bleeding or vessel injury.

CONCLUSIONS

When an aneurysm is located just below the falx and is exposed inadequately, performing wedge resection of the falx can expose the aneurysms adequately for application of the clip.

Current decision-making in meningiomas

The incidence of meningiomas is rising and the number of incidental cases is increasing steadily. The efficiency and the safety of each treatment strategy are also improving over time. Therefore the indications to treat meningiomas are constantly changing. The aim of meningioma treatment is keeping the patient fully functional while achieving long-term relief or prevention from problems related to intracranial tumor growth. This chapter reviews the natural history and treatment results and aims to put together the information for the most objective decision-making in treating meningiomas. Factors acting on the treatment decision such as anatomical localization, symptomatology, variations in tumor biology, recurrence status, age and co-morbidities, operative gains, and patient preference are individually discussed.

Natural history of intracranial meningiomas

We know that the extent of resection is the greatest predictor of long-term survival. However, the potential tradeoff for gross total resection in difficult locations is diminished quality of life. Benign subtotally resected or small incidentally discovered meningiomas may be followed clinically especially in the elderly. In addition, radiosurgery plays a role in the treatment of meningiomas as a primary treatment modality, or as a salvage therapy. Decisions regarding management should be made with an understanding of the natural history and rate of growth. In this chapter we review the known meningioma epidemiology as well as the growth patterns of meningiomas based upon location.

Elderly Patients with Frontobasal and Suprasellar Meningiomas: Safety and Efficacy of Tumor Removal via Frontolateral Approach

OBJECTIVE

Many neurosurgeons prefer conservative treatments in the elderly because of higher rates of mortality and morbidity after surgery. We aim to evaluate safety and efficacy of surgery in elderly patients with frontobasal and suprasellar meningiomas with a simple operative procedure, the frontolateral approach.

METHODS

Retrospective analysis was made in consecutive patients with meningiomas operated via frontolateral approach. They were divided into 2 groups: elderly group (age ≥ 65 years) and young group (age < 65 years). Multivariate logistic regression analysis was performed for postoperative complications and Karnofsky Performance Scale score (KPS).

RESULTS

The study comprises 128 patients operated over a 19-year period, of which 35 patients were in the elderly group and 93 patients were in the young group. More elderly patients presented with American Society of Anesthesiology (ASA) class II and III (57.1% vs. 43%). Gross resection was achieved in 31 cases in the elderly and 85 cases in young group (88.6% vs. 90.3%, P = 0.17). Postoperative KPS in both groups was improved (85.7% vs. 91.4%, P = 0.18). One death occurred in elderly group (2.9%, P = 0.27). Approach-related and medical morbidity in the elderly group was slightly higher than in the young group without significant difference (respectively, 11.4% and 14.3% vs. 9.7% and 8.6%, P = 0.18). Multivariate logistic regression showed increasing age was not associated with approach-related morbidity (odds ratio [OR]: 1.39, P = 0.53), medical morbidity (OR: 1.94, P = 0.88), and improvement of KPS (OR: 0.32, P = 0.25).

CONCLUSIONS

Frontobasal and suprasellar meningiomas in elderly patients can be treated surgically with acceptably low morbidity and mortality rates via the frontolateral approach. Preoperative KPS score ≤60 and ASA classification ≥III predict an unfavorable postoperative outcome.

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.

Decision-making algorithm for minimally invasive approaches to anterior skull base meningiomas

OBJECTIVE Anterior skull base meningiomas are benign lesions that cause neurological symptoms through mass effect on adjacent neurovascular structures. While traditional transcranial approaches have proven to be effective at removing these tumors, minimally invasive approaches that involve using an endoscope offer the possibility of reducing brain and nerve retraction, minimizing incision size, and speeding patient recovery; however, appropriate case selection and results in large series are lacking. METHODS The authors developed an algorithm for selecting a supraorbital keyhole minicraniotomy (SKM) for olfactory groove meningiomas or an expanded endoscopic endonasal approach (EEA) for tuberculum sella (TS) or planum sphenoidale (PS) meningiomas based on the presence or absence of olfaction and the anatomical extent of the tumor. Where neither approach is appropriate, a standard transcranial approach is utilized. The authors describe rates of gross-total resection (GTR), olfactory outcomes, and visual outcomes, as well as complications, for 7 subgroups of patients. Exceptions to the algorithm are also discussed. RESULTS The series of 57 patients harbored 57 anterior skull base meningiomas; the mean tumor volume was 14.7 ± 15.4 cm³ (range 2.2-66.1 cm³), and the mean follow-up duration was 42.2 ± 37.1 months (range 2-144 months). Of 19 patients with olfactory groove meningiomas, 10 had preserved olfaction and underwent SKM, and preservation of olfaction in was seen in 60%. Of 9 patients who presented without olfaction, 8 had cribriform plate invasion and underwent combined SKM and EEA (n = 3), bifrontal craniotomy (n = 3), or EEA (n = 2), and one patient without both olfaction and cribriform plate invasion underwent SKM. GTR was achieved in 94.7%. Of 38 TS/PS meningiomas, 36 of the lesions were treated according to the algorithm. Of these 36 meningiomas, 30 were treated by EEA and 6 by craniotomy. GTR was achieved in 97.2%, with no visual deterioration and one CSF leak that resolved by placement of a lumbar drain. Two patients with tumors that, based on the algorithm, were not amenable to an EEA underwent EEA nonetheless: one had GTR and the other had a residual tumor that was followed and removed via craniotomy 9 years later. CONCLUSIONS Utilizing a simple algorithm aimed at preserving olfaction and vision and based on maximizing use of minimally invasive approaches and selective use of transcranial approaches, the authors found that excellent outcomes can be achieved for anterior skull base meningiomas.

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

OBJECTIVE There has been much debate regarding the optimal surgical approach for resecting olfactory groove meningiomas (OGMs). In this paper, the authors analyzed the factors involved in approach selection and reviewed the surgical outcomes in a series of OGMs. METHODS A retrospective review of 28 consecutive OGMs from a prospective database was conducted. Each tumor was treated via one of 3 approaches: transbasal approach (n = 15), pure endoscopic endonasal approach (EEA; n = 5), and combined (endoscope-assisted) transbasal-EEA (n = 8). RESULTS The mean tumor volume was greatest in the transbasal (92.02 cm³) and combined (101.15 cm³) groups. Both groups had significant lateral dural extension over the orbits (transbasal 73.3%, p < 0.001; combined 100%), while the transbasal group had the most cerebral edema (73.3%, p < 0.001) and vascular involvement (66.7%, p < 0.001), and the least presence of a cortical cuff (33.3%, p = 0.019). All tumors in the combined group were recurrent tumors that invaded into the sinonasal cavity. The purely EEA group had the smallest mean tumor volume (33.33 cm³), all with a cortical cuff and no lateral dural extension. Gross-total resection was achieved in 80% of transbasal, 100% of EEA, and 62.5% of combined cases. Near-total resection (> 95%) was achieved in 20% of transbasal and 37.5% of combined cases, all due to tumor adherence to the critical neurovascular structures. The rate of CSF leakage was 0% in the transbasal and combined groups, and there was 1 leak in the EEA group (20%), resulting in an overall CSF leakage rate of 3.6%. Olfaction was preserved in 66.7% in the transbasal group. There was no significant difference in length of stay or 30-day readmission rate between the 3 groups. The mean modified Rankin Scale score was 0.79 after the transbasal approach, 2.0 after EEA, and 2.4 after the combined approach (p = 0.0604). The mean follow-up was 14.5 months (range 1-76 months). CONCLUSIONS The transbasal approach provided the best clinical outcomes with the lowest rate of complications for large tumors (> 40 mm) and for smaller tumors (< 40 mm) with intact olfaction. The role of EEA appears to be limited to smaller, appropriately selected tumors in which olfaction is already absent. EEA also plays an important adjunctive role when combined with the transbasal approach for recurrent OGMs invading the sinonasal cavity. Careful patient selection using an individualized, tailored strategy is important to optimize surgical outcomes.

Incidence, Clinico-Radiological Features and Outcome of Skull Base versus Non-Skull Base Meningiomas Treated in Kuala Lumpur General Hospital: A Five-Year Experience

Background

Meningiomas are the most common intracranial tumours; they account for 13%-26% of all the primary intracranial tumours. Skull base meningiomas make up 25% of all meningiomas and are one of the most difficult intracranial tumours to be managed surgically. This is due to the fact that it is difficult to approach the lesions which are also close to vital structures such as cranial nerves and major blood vessels. Despite the abundance of these cases in Malaysia, local data on meningiomas is scarce.

Methods

This is a retrospective study consisting of 199 patients with meningiomas who have been operated at the Kuala Lumpur General Hospital from January 2010-December 2014. They were categorised into skull base and non-skull base groups. Demography, tumour characteristics, and patient outcomes were analysed. Kaplan-Meier survival curves as well as Cox hazard univariable and multivariable regressions for the possible predictors of survival were analysed.

Results

97.5% of the patients (n = 194) had WHO grade I meningioma and only five patients had WHO grade II meningioma. There was a female predominance (n = 134; 67.3%), with a male-to-female ratio of 1:2. Some 27.1 % patients had skull base meningiomas. Patients with skull base meningiomas had poorer outcomes and discharge conditions (n = 23; 42.6% P < 0.01), in addition to higher risk of incomplete resections (n = 34; 63% P < 0.01). Multivariate cox hazard regressions showed that the skull base meningioma group had four times the risk of death of the non-skull base group.

Conclusions

Symptomatic meningiomas can be curative if the tumour is completely removed. Our study has revealed that skull base meningiomas which were operated locally had higher rates of incomplete resection and poorer surgical outcomes as compared to the non-skull base group. Patients with skull base meningiomas had four times the risk of death vis-à-vis non-skull base ones. More local studies are needed to look into skull base meningiomas for the improvement of its surgical outcomes.

Recurrence of Anterior Skull Base Meningiomas After Endoscopic Endonasal Resection: 10 Years' Experience in a Series of 52 Endoscopic and Transcranial Cases

INTRODUCTION

Although the indication of endoscopic approaches for anterior skull base meningiomas (ASBM) has been progressively refined, there remains a paucity of data on recurrence rates after resection. To analyze and compare recurrence rates of ASBM resected through endoscopic endonasal (EEE) versus transcranial (TCA) approaches.

MATERIAL AND METHODS

We performed a retrospective analysis of patients submitted to the EEE or TCA approach for ASBM resection from May 2006 to January 2016 in our center. Clinical, radiological, and pathology data were retrieved for analysis. Tumor size, location, surgical technique, extent of resection, and tumor grade were assessed. The 2 groups were compared to identify predictors and differences regarding tumor recurrence.

RESULTS

Fifty-two patients (17 olfactory groove meningioma [OGM] and 35 tuberculum sellae meningioma [TSM]) were included; 26 (6 OGM and 20 TSM) underwent EEE and 26 (13 OGM and 13 TSM) TCA, with a mean follow-up of 41 months. Gross total resection was achieved in 38 (73%) patients (18 [69%] in EEE and 20 [77%] in TCA). Eight (15%) patients presented with recurrence: 5 (19%) in the EEE group and 3 (11.5%) in the TCA group without a statistical difference (P = 0.69). Among the recurrences, gross total resection had been achieved in 1 case of each group. In the EEE group, 1 patient underwent TCA for a recurrent tumor and another patient was referred for radiosurgery.

CONCLUSIONS

This study has shown an overall similar recurrence rate of ASBM regardless of the technique used. However, the analysis of larger series with longer follow-up is necessary to clearly define the indications and to fully validate the efficacy of EEE.

Utility of calcium phosphate cement cranioplasty following supraorbital approach for tumor resection

OBJECTIVE

We have previously documented the utility of calcium phosphate cement cranioplasty following retromastoid craniectomy. In this study, we aimed to demonstrate its efficacy following a supraorbital approach for tumor resection.

METHODS

A retrospective analysis of a prospectively maintained database was conducted of eight patients (7 female, 1 male) with anterior cranial fossa meningiomas resected via a supraorbital approach followed by cranioplasty involving adjunctive or sole use of calcium phosphate cement.

RESULTS

Cranioplasty was achieved in all patients. No patient developed an incisional leak. The cohort had a mean follow-up of approximately 3.1 months (range: 0.5-7 months) in which time no further complications were noted. No patients developed post-surgical infections.

CONCLUSION

In our experience, a low incidence of infection or CSF leaks has been noted after the use of calcium phosphate cement retromastoid cranioplasty. Extending this technique to supraorbital craniotomies may minimize incisional CSF leak.

Evaluation of Olfactory Outcome After Frontolateral Approach for Treatment of Suprasellar Tumors

OBJECTIVE

We present the findings of our prospective study assessing olfactory function outcome in patients undergoing a frontolateral approach for the resection of suprasellar lesions.

METHODS

Eighteen consecutive patients (7 females, 11 males) surgically treated at our institute for suprasellar tumors were included in this prospective study. Olfactory function was evaluated at the admission and 14 days after the surgery using the standard 12-item "Sniffin' Sticks" screening (SSS) test. The olfactory outcome was correlated to the following variables: tumor type, size, consistency, and extent of vertical and lateral growth.

RESULTS

Preoperative and postoperative SSS test mean values were, respectively, 9.11 and 8.72 (not significant: P = 0.274). In only 1 case (5%), with larger suprasellar extension, the difference between preoperative and postoperative SSS was ≥3 (reduction of 5 points). At the subjective evaluation, no patient stated a deficit in smelling.

CONCLUSION

The frontolateral craniotomy is a minimally invasive route to treat suprasellar tumors and has a low approach-related morbidity. It allows tumor resection with low risk for the olfactory function. A risk factor for postoperative olfactory deficit could be significant brain retraction.

Minimally Invasive Approaches for Anterior Skull Base Meningiomas: Supraorbital Eyebrow, Endoscopic Endonasal, or a Combination of Both? Anatomic Study, Limitations, and Surgical Application

BACKGROUND

Minimally invasive accesses to the anterior skull base include the endoscopic endonasal approach (EEA) and the supraorbital eyebrow approach. These 2 are often seen as competing approaches, not alternative or combinatory approaches. In this study, we evaluated the anatomic limitations of each approach and the combined approach for accessing the anterior skull base.

METHODS

Ten neurovascular injected cadaver heads were used for the study. The supraorbital approach to the anterior skull base was performed on 5 heads, and EEA was done on the other 5 heads. Then, the supraorbital approach was added to the 5 heads receiving EEA. Visualization and surgical limitations were recorded by the ability to perform resection of the crista galli, anterior clinoid, cribriform plate, and planum sellae.

RESULTS

The maximal lateral extension of EEA for anterior skull base was the midorbit line anteriorly but narrowing down toward the orbital apex. The limitation of the supraorbital approach was found mostly medial and anterior. Drilling of anterior skull base was impossible medially between the sphenoethmoidal suture and the posterior aspect of the crista galli. The combined approach showed complementary areas of visualization and surgical maneuverability. Three clinical cases were presented to illustrate the indications for the stand-alone supraorbital approach, EEA, and combined approach.

CONCLUSION

The limitations of the EEA when dealing with lateral extension of anterior skull base meningiomas, and the limitations of the supraorbital eyebrow approach for medial skull base drilling and reconstruction, can be overcome by a judicious, anatomically based combination of both approaches.

[The trans-eyebrow supraorbital approach for removal of anterior cranial fossa and suprasellar meningiomas]

Over the past two decades, improvements in surgical tools, navigation systems, and endoscopic techniques have resulted in the widespread use of keyhole surgery for a wide range of skull base tumors. Currently, the trans-eyebrow supraorbital approach is being increasingly used in surgery for anterior cranial fossa and parasellar tumors.

MATERIAL AND METHODS

The study included 7 patients who underwent surgery for meningioma using the trans-eyebrow supraorbital approach at the Burdenko Neurosurgical Institute in the period between 2013 and 2017. The age of patients ranged from 51 to 75 years (median, 60 years); there were 5 females and 2 males. The maximum diameter of resected tumors ranged from 20 to 60 mm (median 40 mm).

RESULTS

Total resection of the tumor was achieved in all 7 cases, which was confirmed by postoperative MRI control. All 7 patients had a good cosmetic result. In 1 case, there was postoperative cerebrospinal fluid rhinorrhea due to incomplete closure of the frontal sinus, which required the patient to be re-operated. None of 7 cases was associated with injury to the main vessels or cavernous sinus.

CONCLUSION

Supraorbital trans-eyebrow craniotomy provides a minimally invasive approach for removing most anterior cranial fossa base and suprasellar tumors. The advantages of keyhole surgery, in comparison with traditional craniotomies, are minimal complications associated with the approach.

[A supraorbital trans-eyebrow approach in surgery of chiasmatic-sellar and anterior cranial fossa tumors]

OBJECTIVE

to analyze 31 resections of chiasmatic-sellar region (CSR) and anterior cranial fossa (ACF) tumors using the supraorbital trans-eyebrow approach (STA).

MATERIAL AND METHODS

We analyzed medical histories of 31 patients who underwent tumor resection using STA in the period between October 2013 and April 2017. We analyzed the age and gender of patients, size and location of the tumor, presence of a neurological deficit, vision and olfactory functions before and after surgery, surgery duration, amount of intraoperative blood loss, rate of frontal sinus trephination and nasal liquorrhea, hemorrhagic and ischemic complications after surgery, Simpson grade of tumor resection, patient's condition before and after surgery (Glasgow Outcome Scale and Karnofsky Scale), and degree of patient satisfaction with the cosmetic result of surgery. A total of 26 meningiomas (20 sphenoid plate, tubercle, and diaphragm tumors, 3 lesser sphenoid wing meningiomas, 2 orbital roof tumors, and 1 anterior clinoid process meningioma), 3 frontal lobe gliomas, and 2 pituitary adenomas were resected.

RESULTS

In all 31 operations, the approach was adequate and enabled tumor resection without lethal outcomes. The mean surgery duration was 174.6±64.4 min. The mean blood loss was 190±96.6 mL (50-380 mL). After surgery, none of the patients developed motor deficits and new epileptic seizures. Neurological deficit aggravation in the form of impaired vision and mental disorders occurred in 8 (25.8%) patients. Vision impaired in 4 (12.9%) patients, improved in 6 (19.3%) patients, and remained unchanged in 21 (67.7%) patients. An endocrinological deficit in the form of partial hypopituitarism developed in 3 (9.6%) patients; in 4 (12.9%) patients, there were mental disorders that regressed by the end of the first month of therapy. There were no intracerebral and subarachnoid hemorrhages. In 2 (6.4%) patients, small epidural hematomas were diagnosed, which did not require surgical treatment. There were only good outcomes (a GOS score of 4 or 5). After surgery, the median Karnofsky index in the STA group was 90±7. In all 31 (100%) patients, the postoperative wound healed by primary intention, without infectious complications and wound liquorrhea. One (4%) patient developed eyebrow palsy; 3 (12%) patients had hypoesthesia in the supraorbital region. The mean VAS score of patient satisfaction with the cosmetic result was 9.36 (median 10±1). The mean follow-up period was 16.2±13.5 months (2-38 months).

CONCLUSION

The STA is adequate for removal of CSR and ACF tumors under proper selection of patients. It provides an adequate view of anatomical structures and enables successful tumor resection through a less traumatic access.

Limitations of the endonasal endoscopic approach in treating olfactory groove meningiomas. A systematic review

OBJECTIVE

To review current management strategies for olfactory groove meningioma (OGM)s and the recent literature comparing endoscopic endonasal (EEA) with traditional transcranial (TCA) approaches.

METHODS

A PubMed search of the recent literature (2011-2016) was performed to examine outcomes following EEA and TCA for OGM. The extent of resection, visual outcome, postoperative complications and recurrence rates were analyzed using percentages and proportions, the Fischer exact test and the Student's t-test using Graphpad PRISM 7.0Aa (San Diego, CA) software.

RESULTS

There were 444 patients in the TCA group with a mean diameter of 4.61 (±1.17) cm and 101 patients in the EEA group with a mean diameter of 3.55 (± 0.58) cm (p = 0.0589). GTR was achieved in 90.9% (404/444) in the TCA group and 70.2% (71/101) in the EEA group (p < 0.0001). Of the patients with preoperative visual disturbances, 80.7% (21/26) of patients in the EEA cohort had an improvement in vision compared to 12.83%(29/226) in the TCA group (p < 0.0001). Olfaction was lost in 61% of TCA and in 100% of EEA patients. CSF leaks and meningitis occurred in 25.7% and 4.95% of EEA patients and 6.3% and 1.12% of TCA patients, respectively (p < 0.0001; p = 0.023).

CONCLUSIONS

Our updated literature review demonstrates that despite more experience with endoscopic resection and skull base reconstruction, the literature still supports TCA over EEA with respect to the extent of resection and complications. EEA may be an option in selected cases where visual improvement is the main goal of surgery and postoperative anosmia is acceptable to the patient or in medium-sized tumors with existing preoperative anosmia. Nevertheless, based on our results, it seems more prudent at this time to use TCA for the majority of OGMs.

SMO mutation status defines a distinct and frequent molecular subgroup in olfactory groove meningiomas

Background

Meningiomas are the most common primary intracranial tumors in adults. Identification of SMO and AKT1 mutations in meningiomas has raised the hope for targeted therapies. It would be useful to know the precise frequency of these mutations in anatomical subgroups and clarify their prognostic value.

Methods

We used the Sanger sequencing technique to characterize 79 samples of olfactory groove meningiomas for SMO (L412F and W535L) and AKT1E17K mutations. We reviewed clinical data to assess the prognostic value of these mutations in this anatomical subgroup.

Results

Out of the 79 patients with olfactory groove meningiomas, we identified targetable mutations in 34 patients (43%) (22 patients [28%] with SMO mutation-L412F almost exclusively-and 12 patients [15%] with AKT1 mutation). Meningiomas in the SMO-mutant group had an overall 36% recurrence rate, significantly higher than in the AKT1-mutant group (16%) and in the "SMO and AKT1 wildtype" group (11%) (χ2 test, P = .04). All late recurrences (after 5 y) occurred in the SMO-mutant group. Among grade I meningiomas, the SMO-mutant group was identified as having a significantly poorer prognosis. World Health Organization histological grade II (P = .006) and incomplete resection (P = .001) were independently associated with shorter recurrence-free survival.

Conclusion

Molecular diagnosis of SMOL412F/W535L and AKT1E17K mutations improves prognostic evaluation in olfactory groove meningiomas and opens new therapeutic perspectives with SMO or AKT inhibitors for recurrent cases.

Endoscopic Assisted Supraorbital Keyhole Approach or Endoscopic Endonasal Approach in Cases of Tuberculum Sellae Meningioma: Which Surgical Route Should Be Favored?

OBJECTIVE

Keyhole approaches are under investigation for skull base tumor surgery. They are expected to have a low complication rate with the same successful resection rate compared with endoscopic endonasal procedures. In this study, we compare our current series of tuberculum sellae meningiomas resected via an endoscopic endonasal or microsurgical supraorbital keyhole approach.

METHODS

Between 2011 and 2016, 16 patients were treated using the supraorbital keyhole procedure and 6 patients received an endoscopic endonasal procedure. Both surgical techniques were analyzed and compared concerning complications, surgical radicality, endocrinologic, and ophthalmologic outcome and recurrences in patients' follow-up.

RESULTS

The 2 different approaches yielded similar rates of gross total resection (endonasal 83% [5 of 6] vs. supraorbital 87% [14 of 16]), near total resection (17% [1 of 6] vs. 13% [2 of 16]), and visual recovery (endonasal 66% [2 of 3] vs. supraorbital 60% [3 of 5]). An extension lateral to the internal carotid artery was noted in 81% (13 of 16) of the supraorbital cases and in none of the endonasal cases. Tumor volume was 14.9 cm³ (±8.2 cm³) for supraorbital tumors versus 2.1 cm³ (±0.8 cm³) for the endonasal approach.

CONCLUSIONS

Both approaches provide minimally invasive surgical routes accessing meningiomas of the sellar region. The ideal approach should be tailored to the individual patient considering the tumor anatomy, lateral extension, and the experience of the surgeon with both surgical approaches. We suggest using the supraorbital approach for larger meningiomas of sellar region with far lateral extension or broad vascular encasement.

Supraorbital Versus Endoscopic Endonasal Approaches for Olfactory Groove Meningiomas: A Cost-Minimization Study

OBJECTIVE

To perform a cost-minimization study comparing the supraorbital and endoscopic endonasal (EEA) approach with or without craniotomy for the resection of olfactory groove meningiomas (OGMs).

METHODS

We built a decision tree using probabilities of gross total resection (GTR) and cerebrospinal fluid (CSF) leak rates with the supraorbital approach versus EEA with and without additional craniotomy. The cost (not charge or reimbursement) at each "stem" of this decision tree for both surgical options was obtained from our hospital's finance department. After a base case calculation, we applied plausible ranges to all parameters and carried out multiple 1-way sensitivity analyses. Probabilistic sensitivity analyses confirmed our results.

RESULTS

The probabilities of GTR (0.8) and CSF leak (0.2) for the supraorbital craniotomy were obtained from our series of 5 patients who underwent a supraorbital approach for the resection of an OGM. The mean tumor volume was 54.6 cm³ (range, 17-94.2 cm³). Literature-reported rates of GTR (0.6) and CSF leak (0.3) with EEA were applied to our economic analysis. Supraorbital craniotomy was the preferred strategy, with an expected value of $29,423, compared with an EEA cost of $83,838. On multiple 1-way sensitivity analyses, supraorbital craniotomy remained the preferred strategy, with a minimum cost savings of $46,000 and a maximum savings of $64,000. Probabilistic sensitivity analysis found the lowest cost difference between the 2 surgical options to be $37,431.

CONCLUSION

Compared with EEA, supraorbital craniotomy provides substantial cost savings in the treatment of OGMs. Given the potential differences in effectiveness between approaches, a cost-effectiveness analysis should be undertaken.