Taste dysfunction after endoscopic endonasal resection of olfactory groove meningioma: Case series and review of the literature.

PURPOSE: The incidence of ageusia and dysgeusia after endoscopic endonasal (EEA) resection of olfactory groove meningioma (OGM) is not well established despite recognized impairment in olfactory function. METHODS: We retrospectively administered a validated taste and smell survey to patients undergoing EEA for resection of OGM at two institutions. Demographics and clinical characteristics were collected and survey responses were analyzed. RESULTS: Twelve patients completed the survey. The median time from surgery was 24 months. The average total complaint score was 5.5 out of 16 [0-13]. All patients reported a change in sense of smell while only 42 % reported a change in sense of taste. Taste changes did not consistently associate with laterality or size of the neoplasm. Significant heterogeneity existed when rating severity of symptoms. CONCLUSIONS: To our knowledge this is the first case series examining taste changes after EEA resection of OGM. Despite universal olfactory dysfunction, only a minority of patients reported a change in their sense of taste. Our findings may improve patient counseling and expectations after surgery.

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.

How I Do It: Endonasal transethmoidal, transcribriform approach for resection of giant olfactory groove meningioma.

BACKGROUND: Olfactory groove meningiomas (OGMs) arise from the cribriform plate of the anterior fossa and account for 9-12% of all meningiomas. Giant OGMs are those larger than 6 cm and are technically challenging to resect. METHOD: Here we present the surgical decision-making and intraoperative details regarding the endonasal endoscopic resection of an OGM using a minimally invasive, endonasal approach in a 68-year-old female patient. CONCLUSION: Giant OGMs can be safely and effectively removed using an endonasal, transcribriform approach.

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.

Eyebrow supraorbital keyhole craniotomy for olfactory groove meningiomas with endoscope assistance: case series and systematic review of extent of resection, quantification of postoperative frontal lobe injury, anosmia, and recurrence.

BACKGROUND: Olfactory groove meningiomas (OGMs) are commonly treated with open craniotomy. Endonasal approaches have also been described. OBJECTIVE: To present clinical and radiographic outcomes for the minimally invasive eyebrow incision supraorbital keyhole approach with endoscopic assistance for OGMs. METHODS: We performed a retrospective single-center cohort study and a systematic literature review. RESULTS: Fifteen patients were identified, all with Grade I meningiomas. Radiographic gross total resection of enhancing tumor was achieved in all patients. Mean frontal lobe fluid-attenuated inversion recovery volume decreased from 11.1 ± 18.3 cm3 preoperatively to 9.9 ± 11.4 cm3 immediately postoperatively, and there was minimal new restricted diffusion (3.2 ± 2.2 cm3; max 7.5 cm3). Median length of stay was 3 days (range 2-8). Vision was improved in 4 (80%) and stable in 1 (20%) of 5 patients with a preoperative deficit. New postoperative anosmia occurred in 3 (23%) of 13 patients with any preoperative olfaction. All patients were satisfied with their cosmetic result at 3 months. After a median follow-up of 32.2 months, there were 2 (13.3%) asymptomatic radiographic recurrences, 1 treated with radiosurgery and the other with endoscopic endonasal approach (EEA). No patients required further craniotomy. Systematic review revealed the present series to be the largest to date reporting disaggregated outcomes for the eyebrow approach to OGM. CONCLUSION: The eyebrow incision supraorbital keyhole craniotomy with endoscopic assistance is a safe and effective approach to OGM with tumor control rates similar to more invasive open approaches and better than the endonasal approach. Rates of frontal lobe injury, CSF leak and anosmia are comparatively low.

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.

Giant nasofrontal meningioma: endoscopic and transcranial approach followed by microvascularized vastus laterallis flap reconstruction.

A 12-year-old girl presented with headache, nasal voice, and anosmia. Magnetic resonance imaging demonstrated a 11 × 9 × 8-cm tumor extending from the nasal cavity to the frontal lobes. Histological analysis was consistent with transitional meningioma WHO grade I. As far as we know, this is the first reported case of a giant olfactory groove meningioma invading the nasal cavity through the anterior cranial base. Complete surgical removal was accomplished with excellent result via a staged endoscopic and transcranial approach. A microvascularized vastus laterallis flap was used for reconstruction. Surgical options and technical details in the management of this lesion are reviewed.

Surgical nuances of the expanded endoscopic anterior skull base craniectomy for hyperostotic meningioma resection.

BACKGROUND: The rostral expanded endoscopic approach (EEA) to anterior cranial fossa (ACF) has several advantages over transcranial/craniofacial surgery, providing early access to the vascular supply of tumors and reducing morbidities of craniotomy especially that of brain retraction. This article presents endoscopic landmarks and nuances for a wide ACF corridor, with stepwise image-guided dissections highlighting surgical tricks and techniques to enhance surgical safety. METHODS: We describe an expanded endoscopic endonasal anterior skull base craniectomy for a recurrent large olfactory groove hyperostotic meningioma, with correlated cadaveric dissections. CONCLUSION: The widening of rostral EEA can provide a safe and feasible route to access ACF. This article highlights the specific landmarks in endoscopic anatomy with reference to the angle of visualization and bayonetted instruments.

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.

The endoscopic endonasal approach is not superior to the microscopic transcranial approach for anterior skull base meningiomas-a meta-analysis.

OBJECT: In the past decade, the endonasal transsphenoidal approach (eTSA) has become an alternative to the microsurgical transcranial approach (mTCA) for tuberculum sellae meningiomas (TSMs) and olfactory groove meningiomas (OGMs). The aim of this meta-analysis was to evaluate which approach offered the best surgical outcomes. METHODS: A systematic review of the literature from 2004 and meta-analysis were conducted in accordance with the PRISMA guidelines. Pooled incidence was calculated for gross total resection (GTR), visual improvement, cerebrospinal fluid (CSF) leak, intraoperative arterial injury, and mortality, comparing eTSA and mTCA, with p-interaction values. RESULTS: Of 1684 studies, 64 case series were included in the meta-analysis. Using the fixed-effects model, the GTR rate was significantly higher among mTCA patients for OGM (eTSA: 70.9% vs. mTCA: 88.5%, p-interaction < 0.01), but not significantly higher for TSM (eTSA: 83.0% vs. mTCA: 85.8%, p-interaction = 0.34). Despite considerable heterogeneity, visual improvement was higher for eTSA than mTCA for TSM (p-interaction < 0.01), but not for OGM (p-interaction = 0.33). CSF leak was significantly higher among eTSA patients for both OGM (eTSA: 25.1% vs. mTCA: 10.5%, p-interaction < 0.01) and TSM (eTSA: 19.3%, vs. mTCA: 5.81%, p-interaction < 0.01). Intraoperative arterial injury was higher among eTSA (4.89%) than mTCA patients (1.86%) for TSM (p-interaction = 0.03), but not for OGM resection (p-interaction = 0.10). Mortality was not significantly different between eTSA and mTCA patients for both TSM (p-interaction = 0.14) and OGM resection (p-interaction = 0.88). Random-effect models yielded similar results. CONCLUSION: In this meta-analysis, eTSA was not shown to be superior to mTCA for resection of both OGMs and TSMs.

Olfactory groove meningiomas: An analysis based on surgical experience with 129 cases.

OBJECTIVE: The surgical strategy and outcome for 129 patients operated for an olfactory groove meningioma is retrospectively analyzed. MATERIAL AND METHODS: One hundred and twenty nine patients with an olfactory groove meningioma operated between the years 1987 and 2016 were analyzed on the basis of clinical and radiological factors that appeared to affect the conduct of surgery and its outcome. Each factor was given points, and the points were added to obtain a score. On the basis of the score, the tumors were divided into three grades. The grades determined the difficulties that could be anticipated during surgery. In the initial part of the series, a bifrontal craniotomy was done to resect the tumor in all patients. In the later half of the series, majority of the patients were operated by the use of a unifrontal craniotomy. The aim of surgery was to resect the tumor completely. RESULTS: Total tumor resection was achieved in 86 patients, and subtotal tumor resection with less than 10% tumor left behind was achieved in 43 patients. Seven patients died in the immediate postoperative period. All patients where a subtotal tumor resection was done and where the patient died after surgery had a higher grade tumor. The average follow-up period was 82 months. There was non-symptomatic recurrence in 11 patients. CONCLUSIONS: The location and size of the tumor, extent and duration of visual symptoms, extent of tumor adjoining cerebral edema, encasement of anterior cerebral artery complex and extension in the extracranial compartment were more important factors that affected the outcome of surgery.

Bicoronal frontobasal approach with a limited, midline orbital bar osteotomy - a technical note.

The frontobasal approach remains a workhorse for removing large olfactory groove meningiomas. Removal of the orbital bar in addition to standard bifrontal craniotomy allows for additional basal exposure, minimising brain retraction and allowing early and direct access to both the vascular supply and dural origin of this tumour. Here, we describe a simple yet effective modification to the standard orbital bar osteotomy. It has the benefit of being simpler and faster with improved cosmesis compared with an osteotomy of the entire orbital bar. It also has the advantage of not requiring manipulation of the supraorbital nerves or intraorbital or periorbital dissection.

Resection of olfactory groove meningioma - a review of complications and prognostic factors.

INTRODUCTION: High complication rates have been cited following olfactory groove meningioma (OGM) resection but data are lacking on attendant risk factors. We aimed to review the complications following OGM resection and identify prognostic factors. METHODS: A retrospective review was performed on 34 consecutive patients who underwent primary OGM resection at a single London institution between March 2008 and February 2013. Collected data included patient comorbidities, pre-operative corticosteroid use, tumour characteristics, imaging features, operative details, extent of resection, histology, use of elective post-operative ventilation, complications, recurrence and mortality. RESULTS: Complication rate was 39%. 58% of complications required intensive care or re-operation. Higher complication rates occurred with OGM > 40 mm diameter versus ≤ 40 mm (53 vs. 28%; p = 0.16); OGM with versus without severe perilesional oedema (59 vs. 19%; p = 0.26), more evident when corrected for tumour size; and patients receiving 1-2 days versus 3-5 days of pre-operative dexamethasone (75 vs. 19%; p = 0.016). Patients who were electively ventilated post-operatively versus those who were not had higher risk tumours but a lower complication rate (17 vs. 44%; p = 0.36) and a higher proportion making a good recovery (83 vs. 55%; p = 0.20). Complete versus incomplete resection had a higher complication rate (50 vs. 23%; p = 0.16) but no recurrence (0 vs. 25%; p = 0.07). CONCLUSION: Risk of morbidity with OGM resection is high. Higher complication risk is associated with larger tumours and greater perilesional oedema. Pre-operative dexamethasone for 3-5 days versus shorter periods may reduce the risk of complications. We describe a characteristic pattern of perilesional oedema termed 'sabre-tooth' sign, whose presence is associated with a higher complication rate and may represent an important radiological prognostic sign. Elective post-operative ventilation for patients with high-risk tumours may reduce the risk of complications.

Septal transposition: a novel technique for preservation of the nasal septum during endoscopic endonasal resection of olfactory groove meningiomas.

Endonasal resection of olfactory groove meningiomas allows for several advantages over transcranial routes, including a direct approach to the bilateral anterior cranial base and dura mater, early tumor devascularization, and avoidance of brain retraction. Although considered minimally invasive, the endoscopic approach to the cribriform plate typically requires resection of the superior nasal septum, resulting in a large superior septal perforation. The septal transposition technique improves preservation of sinonasal anatomy through the elimination of a septal perforation while allowing for wide exposure to the midline anterior cranial base and harvest of a nasal septal flap. Herein, the authors describe a 39-year-old female who presented with a progressively enlarging olfactory groove meningioma. An endoscopic endonasal resection with a septal transposition technique was performed. On follow-up, the nasal cavity had completely normal anatomy with preservation of the turbinates and nasal septum. The authors conclude that septal transposition is a useful technique that allows wide exposure of the anterior cranial base with maximal preservation of normal nasal anatomy and avoidance of a large septal perforation.

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.

Bilateral cranioorbital foramina (Hyrtl foramina): crucial anatomical findings in the management of giant olfactory groove meningioma - a case report and literature review.

Presence of bilateral cranio-orbital foramina, AKA Hyrtl foramina is rare yet existing. They carry the risks of retinal artery emboli due to reflux embolization for the neurovascular interventionalists, navigating complexities in olfactory groove meningioma management. A 59-year-old woman with progressive frontal lobe syndrome presented a large olfactory groove meningioma primarily supplied by bilateral sphenopalatine arteries together with bilateral anterior cerebral arteries, necessitating risky preoperative embolization and meticulous resection. This case underscores the intricate nature of vascular supply in frontal skull base tumors, emphasizing the need for multidisciplinary approaches, thorough preoperative planning, and detective research to optimize treatment outcomes.

Exoscopic resection of giant olfactory groove meningioma.

Olfactory groove meningiomas represent 8%-13% of all intracranial meningiomas. Gross-total resection for large (4-6 cm) and giant (> 6 cm) cases remains challenging due to their relationship with critical neurovascular structures and extensive frontal lobe edema. A variety of transcranial and endoscopic approaches have been described. This 2D operative video shows the use of a digital 3D exoscope in the removal of a giant olfactory groove meningioma through a lateral supraorbital approach in a 57-year-old woman with visual impairment and apathy. The exoscope provides a very good angulated view of the subfrontal area on both sides of the anterior cranial fossa even through a small craniotomy. The video can be found here: https://stream.cadmore.media/r10.3171/2023.10.FOCVID23125.

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.

A modern approach to olfactory groove meningiomas.

OBJECTIVE: Management of olfactory groove meningiomas (OGMs) has changed significantly with the advances in extended endoscopic endonasal approaches (EEAs), which is an excellent approach for patients with anosmia since it allows early devascularization and minimizes retraction on the frontal lobes. Craniotomy is best suited for preservation of olfaction. However, not infrequently, a tumor presents after extending outside the reach of an EEA and a solely transcranial approach would require manipulation and retraction of the frontal lobes. These OGMs may best be treated by a staged EEA-craniotomy approach. In this study the authors' goal was to present their case series of patients with OGMs treated with their surgical approach algorithm. METHODS: The authors conducted an IRB-approved, nonrandomized historic cohort including all consecutive cases of OGMs treated surgically between 2010 and 2020. Patient demographic information, presenting symptoms, operative details, and complications data were collected. Preoperative and postoperative tumor and T2/FLAIR intensity volumes were calculated using Visage Imaging software. RESULTS: Thirty-one patients with OGMs were treated (14 craniotomy only, 11 EEA only, and 6 staged). There was a significant difference in the distribution of patients presenting with anosmia and visual disturbance by approach. Tumor size was significantly correlated with preoperative vasogenic edema. Gross-total resection was achieved in 90% of cases, with near-total resection occurring twice with EEA and once with a staged approach. T2/FLAIR hyperintensity completely resolved in 90% of cases and rates did not differ by approach. Complication rates were not significantly different by approach and included 4 CSF leaks (p = 0.68). CONCLUSIONS: A staged approach for the management of large OGMs with associated anosmia and significant lateral extension is a safe and effective option for surgical management. Through utilization of the described algorithm, the authors achieved a high rate of GTR, and this strategy may be considered for large OGMs.

The unilateral frontotemporal approach for large and giant olfactory groove meningioma: Experience with 18 consecutive patients.

AIM: Although the bifrontal approach used to be recommended for large olfactory groove meningioma (OGM), recent studies showed that large OGMs can also be resected safely via unilateral approaches. The present study aimed to discuss reasons for preferring a unilateral frontotemporal approach (UFTA), and the technical nuances and results of the UFTA, based on 18 cases. MATERIAL AND METHODS: The clinical and surgical data of patients who had been operated on for large (4-6cm) or giant (>6cm) OGM via a UFTA between 2011 and 2018 were retrospectively collected. RESULTS: In all, 18 patients were included. All tumors were compatible with a diagnosis of OGM in the light of peri-operative examinations. 11 cases (61%) were large and 7 (39%) giant OGM; mean diameter was 6.1cm (range, 4-10cm). Resection extent was Simpson grade II in 14 cases (78%), grade III in 1 (5%), and grade IV in 3 (17%). Sixteen cases (89%) had no peri-operative complications, while 2 patients (11%) showed cerebrospinal fluid leakage and hemorrhagic deposition in the surgical area. There were no new neurological deficits nor deaths. CONCLUSION: The UFTA for OGM is a relatively safe and effective approach, ensuring a high total removal rate with low mortality and morbidity. This study, with a reasonable number of patients, is one of the few in the literature on the outcome of this approach.