A modern approach to olfactory groove meningiomas

J Neurosurg 140:1215–1222, 2024

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.

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

Neurosurgery 89:784–791, 2021

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

OBJECTIVE: To investigate the safety and efficacy of SRS for OGMs.

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

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

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

 

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

Acta Neurochirurgica (2021) 163:661–676

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 effective- ness, 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.

 

Eyebrow supraorbital keyhole craniotomy for olfactory groove meningiomas with endoscope assistance

Acta Neurochirurgica (2021) 163:101–112

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

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

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

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

Endoscopic Endonasal Transethmoidal Transcribriform Transfovea Ethmoidalis Approach to the Anterior Cranial Fossa and Skull Base

Neurosurgery 66:883-892, 2010 DOI: 10.1227/01.NEU.0000368395.82329.C4

The anterior skull base, in front of the sphenoid sinus, can be approached using a variety of techniques including extended subfrontal, transfacial, and craniofacial approaches. These methods include risks of brain retraction, contusion, cerebrospinal fluid leak, meningitis, and cosmetic deformity. An alternate and more direct approach is the endonasal, transethmoidal, transcribriform, transfovea ethmoidalis approach.

METHODS: An endoscopic, endonasal approach was used to treat a variety of conditions of the anterior skull base arising in front of the sphenoid sinus and between the orbits in a series of 44 patients. A prospective database was used to detail the corridor of approach, closure technique, use of intraoperative lumbar drainage, operative time, and postoperative complications. Extent of resection was determined by a radiologist using volumetric analysis.

RESULTS: Pathology included meningo/encephaloceles (19), benign tumors (14), malignant tumors (9), and infectious lesions (2). Lumbar drains were placed intraoperatively in 20 patients. The CSF leak rate was 6.8% for the whole series and 9% for intradural cases. Leaks were effectively managed with lumbar drainage. Early reoperation for cerebrospinal fluid (CSF) leak occurred in 1 patient (2.2%). There were no intracranial infections. Greater than 98% resection was achieved in 12 of 14 benign and 5 of 9 malignant tumors.

CONCLUSION: The endoscopic, endonasal, transethmoidal, transcribriform, transfovea ethmoidalis approach is versatile and suitable for managing a variety of pathological entities. This minimal access surgery is a feasible alternative to transcranial, transfacial, or combined craniofacial approaches to the anterior skull base and anterior cranial fossa in front of the sphenoid sinus. The risk of CSF leak and infection are reasonably low and decrease with experience. Longer follow-up and larger series of patients will be required to validate the long-term efficacy of this minimally invasive approach.

Endoscopic Endonasal Transethmoidal Transcribriform Transfovea Ethmoidalis Approach to the Anterior Cranial Fossa and Skull Base

Neurosurgery 66:1-10, 2010. DOI: 10.1227/01.NEU.0000368395.82329.C4

The anterior skull base, in front of the sphenoid sinus, can be approached using a variety of techniques including extended subfrontal, transfacial, and craniofacial approaches. These methods include risks of brain retraction, contusion, cerebrospinal fluid leak, meningitis, and cosmetic deformity. An alternate and more direct approach is the endonasal, transethmoidal, transcribriform, transfovea ethmoidalis approach.

METHODS: A purely endoscopic, endonasal approach was used to treat a variety of conditions of the anterior skull base arising in front of the sphenoid sinus and between the orbits in a series of 44 patients. A prospective database was used to detail the corridor of approach, closure technique, use of intraoperative lumbar drainage, operative time, and postoperative complications. Extent of resection was determined by a radiologist using volumetric analysis.

RESULTS: Pathology included meningo/encephaloceles (19), benign tumors (14), malignant tumors (9), and infectious lesions (2). Lumbar drains were placed intraoperatively in 20 patients. The CSF leak rate was 6.8% for the whole series and 9% for intradural cases. Leaks were effectively managed with lumbar drainage. Early reoperation for cerebrospinal fluid (CSF) leak occurred in 1 patient (2.2%). There were no intracranial infections. Greater than 98% resection was achieved in 12 of 14 benign and 5 of 9 malignant tumors.

CONCLUSION: The purely endoscopic, endonasal, transethmoidal, transcribriform, transfovea ethmoidalis approach is versatile and suitable for managing a variety of pathological entities. This minimal access surgery is a feasible alternative to transcranial, transfacial, or combined craniofacial approaches to the anterior skull base and anterior cranial fossa in front of the sphenoid sinus. The risk of CSF leak and infection are reasonably low and decrease with experience. Longer follow-up and larger series of patients will be required to validate the long-term efficacy of this minimally invasive approach.