Resection Of Olfactory Groove Meningiomas Research Articles

Surgical Approaches to Resection of Olfactory Groove Meningiomas: Comparative Meta-analysis of the Endoscopic Endonasal versus Transcranial and Unilateral versus Bilateral Approaches

Abstract Introduction Here we systematically review the extant literature to highlight the advantages of bilateral versus unilateral approaches and endoscopic endonasal (midline) approaches versus transcranial approaches for olfactory groove meningiomas, focusing on complications, extent of resection, and local recurrence rates. Methods Three databases were queried to identify all primary prospective trials and retrospective series comparing outcomes following endoscopic endonasal versus transcranial approaches and unilateral versus bilateral craniotomy for surgical resection of olfactory groove meningiomas. All articles were screened by two independent authors and selected for formal analysis according to predefined inclusion/exclusion criteria. Results Seven studies comprising 288 total patients (mean age 55.0 ± 24.6 years) met criteria for inclusion. In the three comparing the endoscopic endonasal (n = 21) versus transcranial (n = 32) approaches, there was no significant difference between the two with respect to gross total resection (p = 0.34) or rates of Simpson Grade 1 resection (p = 0.69). EEA demonstrated higher rates of overall complications (p < 0.01) including postoperative infection (p = 0.03). In the four studies comparing bilateral (n = 117) versus unilateral approaches (n = 118), overall complication rates (p < 0.01) and disease recurrence (p = 0.01) were higher with bilateral approaches. All surgery-related mortalities also occurred in the bilateral cohort (n = 7, 7.14%). Gross total resection (p = 0.63) and Simpson grade (p = 0.48) were comparable between approaches. Olfaction preservation was superior for unilateral approaches (p < 0.01). Conclusions Though the literature is limited, current evidence suggests that the endoscopic endonasal approach may be favorable over conventional craniotomy for select olfactory groove meningioma patients. Where craniotomy is used, unilateral approaches appear to reduce complications and the risk of olfaction loss.

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

PurposeThe 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. MethodsWe 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. ResultsTwelve 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. ConclusionsTo 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.

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

ObjectiveThough 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. MethodsWe 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. ResultsAnatomic 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. ConclusionsEndoscopic 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.

Olfactory groove meningiomas: supraorbital keyhole versus orbitofrontal, frontotemporal, or bifrontal approaches.

Olfactory groove meningiomas (OGMs) often require surgical removal. The introduction of recent keyhole approaches raises the question of whether these tumors may be better treated through a smaller cranial opening. One such approach, the supraorbital keyhole craniotomy, has never been compared with more traditional open transcranial approaches with regard to outcome. In this study, the authors compared clinical, radiographic, and functional quality of life (QOL) outcomes between the keyhole supraorbital approach (SOA) and traditional transcranial approach (TTA) for OGMs. They sought to examine the potential advantages and disadvantages of open/TTA versus keyhole SOA for the resection of OGMs in a relatively case-matched series of patients. A retrospective, single-institution review of 57 patients undergoing a keyhole SOA or larger traditional transcranial (frontotemporal, pterional, or bifrontal) craniotomy for newly diagnosed OGMs between 2005 and 2023 was performed. Extent of resection, olfaction, length of stay (LOS), radiographic volumetric assessment of postoperative vasogenic and cytotoxic edema, and QOL (using the Anterior Skull Base Questionnaire) were assessed. Thirty-two SOA and 25 TTA patients were included. The mean EOR was not significantly different by approach (TTA: 99.1% vs SOA: 98.4%, p = 0.91). Olfaction was preserved or improved at similar rates (TTA: 47% vs SOA: 43%, p = 0.99). The mean LOS was significantly shorter for SOA patients (4.1 ± 2.8 days) than for TTA patients (9.4 ± 11.2 days) (p = 0.002). The authors found an association between an increase in postoperative FLAIR cerebral edema and TTA (p = 0.031). QOL as assessed by the ASQB at last follow-up did not differ significantly between groups (p = 0.74). The keyhole SOA was associated with a statistically significant decrease in LOS and less postoperative edema relative to traditional open approaches.

SURG-25. 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

Abstract BACKGROUND There is no consensus regarding whether a frontal or lateral approach is superior for resection of olfactory groove meningiomas (OGM). Objective: 1) To compare surgical approaches for microsurgical resection of OGMs for extent of resection and complication rates. 2) To develop a novel preoperative scoring system to guide choice of approach to decrease surgical morbidity. METHODS A PRISMA-guided pooled analysis of 20,672 surgical reports on OGMs published in the MRI era using search terms such as ‘olfactory groove meningioma’ and ‘surgery’. After title screening and removal of duplicates, we assessed 871 studies on surgical management of OGMs. Following exclusion criteria, 27 studies were chosen for the final pooled cohort analysis of reported patient outcomes. RESULTS The 27 studies identified a total of 1,016 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 27% of surgical OGM patients sustained some form of complications. Minor complications 22.2% (CSF leak, seizures, infection, transient cranial nerve palsies, hydrocephalus). Major complications 4.7% (hemorrhage, ischemic infarct, malignant cerebral edema). Correlation between complications and the surgical approach was performed. Among 426 patients who underwent unilateral approaches, 14% experienced minor complications, and 2.1% experienced major complications. The 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 than bilateral approaches, however, the extent of resection is not uniformly reported, making it difficult to identify differences. We herein propose a novel preoperative imaging-based classification scoring system to help select the most suitable surgical approach to achieve lower post-surgical complication rates.

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.

Bilateral Persistent Primitive Olfactory Arteries Observed During Resection of Olfactory Groove Meningioma: Technical Case Report.

Resection of olfactory groove meningiomas is challenging because of their close proximity with the anterior cerebral circulation. It is important to recognize the vascular variants in procedures at the anterior skull base because inadvertent maneuvers may result in the rupture of these arteries and unexpected bleeding. We reported a type 2 persistent primitive olfactory artery with a dural branch of the elongated anterior cerebral artery directly to the ethmoid region, visualized during the surgical removal of an olfactory groove meningioma. This is the first report of bilateral persistent primitive olfactory artery demonstrated by operative visualization and confirmed with vascular study. Understanding and recognizing the possible variations of this vascular anatomy is of great importance for anterior skull base surgeries.

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

Stereotactic radiosurgery (SRS) is increasingly considered for selected olfactory groove meningiomas (OGMs). To investigate the safety and efficacy of SRS for OGMs. 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. 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 12Gy, and median dose to the olfactory nerve was 11.20Gy. 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). 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.

Olfaction in Olfactory Groove Meningiomas.

Clinical examination, including pre- and postoperative assessment of olfaction, is essential in evaluating surgical outcomes in patients with olfactory groove meningiomas (OGMs). A review of a recent series revealed a lack of assessment of olfaction in most of the studies. Tests determining olfactory detection should be used to reveal olfactory dysfunction. Specialized examination techniques (e.g., electro-olfactography, olfactory evoked potentials, and functional magnetic resonance imaging) are currently used in research. Prospective analysis of 13 patients who underwent surgical resection of OGMs from December 2013 to December 2017 was performed. Data on clinical presentation, pre- and postoperative neurologic examinations, complications, recurrences, adjuvant treatment, and follow-up outpatient examinations were recorded. Olfactory function was assessed using the Sniffin' Sticks odor identification test preoperatively, postoperatively, and 1 year after surgery. All the meningiomas were resected via unilateral craniotomy, and gross total resection was achieved in all cases. Surgery-related permanent morbidity was 7.7% and overall mortality 0%. For the eight patients with preoperative normosmia, five remained normosmic (62.5%), one deteriorated to hyposmia (12.5%), and two deteriorated to anosmia (25%). For the two patients with preoperative hyposmia, one remained hyposmic and one deteriorated to anosmia. For the three anosmic patients, two remained anosmic, and one improved to hyposmia.The intact olfactory function preoperatively was associated with a better olfactory outcome. Overall, 62.5% of these patients remained normosmic, and none of the hyposmic or anosmic patients normalized their olfaction.Higher meningioma volume is associated with worse olfactory function before surgery (normosmia in 16.7% versus 100.0% in less voluminous) and following the surgery (normosmia in 16.7% versus 57.1% less voluminous).The unilateral surgical approach enabled the anatomical preservation of the contralateral olfactory nerve in 76.9% of our patients. Functional normosmia was achieved in 50% and hyposmia in 30% of these cases. Assessment of olfactory function is both vital in preoperative decision making (surgical approach, radicality of resection) and when evaluating surgical outcome. Preoperative normosmia seems to be the most important prognostic factor for functional olfactory outcome. In normosmic patients the olfaction was preserved in 62.5% of cases. Moreover, higher meningioma volume is associated with worse olfactory function before and following the surgery. The greatest advantage of the unilateral surgical approach is anatomical preservation of the contralateral olfactory nerve with a satisfactory functional outcome. These results support a proactive approach, with early surgical resection using a unilateral approach even in cases with less voluminous OGMs that enables the preservation of olfactory function in a significant proportion of patients.

Predicting the Outcome of Microsurgical Resection of Olfactory Groove Meningiomas (OGMs): Experience at Benha University Hospital

AbstractBackground: Radical excision of olfactory groove men-ingioma is the goal of microsurgery but faces some challenges such as the hypersostotic bone and paranasal sinus invasion with resulting Cerebrospinal Fluid (CSF) leak and infection making high recurrence rate.Aim of Study: The aim of the present study was to identify factors predicting the outcome for patients with a diagnosis of OGMs undergoing microsurgical resection and to examine whether there is a general benefit of such microsurgery.Patients and Methods: A total number of 28 patients were microsurgically operated for OGMs at the Neurosurgery Department of Benha University Hospital between January 2012 and December 2018.Results: No patient characteristics, such as age, sex or presenting symptoms could be considered predictive for the post-operative outcome. Of the tumor-related characteristics only the presence of skull base invasion and the Simpson grading of removal were considered negative predictors for the outcome.Conclusions: Microsurgical removal of the OGMs is effective and save with very little morbidity and low risk of post-operative recurrence provided that it is done totally with complete reconstruction of the skull base.

Smell Preservation following Unilateral Endoscopic Transnasal Approach to Resection of Olfactory Groove Meningioma: A Multi-institutional Experience.

Introduction Olfactory groove meningiomas (OGMs) are often associated with loss of smell following resection. Loss of smell has a measurable impact on quality of life. Smell preservation has been previously described in open approaches for early stage or unilateral OGMs. Evidence of smell preservation in endoscopic approaches is lacking. Design A multi-institutional retrospective review was performed on consecutive patients who underwent unilateral endoscopic endonasal resection of OGM. A gross total resection was achieved with preservation of the contralateral olfactory cleft and bulb. Olfactory function was assessed with a six-point olfactory symptom score and the Sniffin' Sticks 12-item smell identification test (SS-12). Contralateral olfactory bulb volume was measured on postoperative magnetic resonance imaging. Results Four patients (age 42.0 ± 7.5, 75% female) were assessed. Olfactory function was assessed at 21.8 ± 5.6 months following surgery. All patients reported some degree of smell preservation (75% described a slight/mild impairment in smell or better). Olfactory identification was preserved with an SS-12 score of 9 ± 1.4 (anosmia defined as ≤6). The olfactory bulb volume was calculated to be 47.4 ± 15.9 mm 3 (normal >40 mm 3 ). Conclusion Smell preservation is possible following unilateral endoscopic endonasal resection of carefully selected OGM.

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

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

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

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

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

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

Minimally Invasive Interhemispheric Approach for Giant Olfactory Groove Meningioma: Technical Note

Skull base tumors, such as large olfactory groove meningiomas (OGMs), are a challenge for neurosurgeons. However, the tendency to reduce invasive surgeries is gaining more adepts. We describe a minimally invasive interhemispheric approach with a falx window for microsurgical resection of the giant OGM as a technical note. A minimal medial frontal craniotomy measuring 3-5 cm in size is performed, and an interhemispheric approach is combined with an opening in the falx to improve microsurgical resection of the giant OGM. The technique and more details are described. A minimally invasive interhemispheric approach with a falx window was performed in this case. Gross total resection of the OGM was possible with minimal brain retraction. Simpson grade I was achieved, and there was a good outcome on the postoperative recovery period of the patient, with vision improvement, preservation of olfaction, and no other complications. The minimally invasive interhemispheric approach with a falx window is effective and safe for giant OGM with a good outcome for the patient. The opening in the falx improves the interhemispheric pathway and allows gross total resection with minimal brain retraction and low morbidity.

Modern microsurgical resection of olfactory groove meningiomas by classical bicoronal subfrontal approach without orbital osteotomies

Background:The olfactory groove meningioma has always been surgically challenging. The common microscopic surgical procedures exercised involve modification of pterional or sub-frontal approaches with or without orbital osteotomies. However, we believe that orbital osteotomies are not mandatory to achieve gross total resection. Hence, this study was performed to evaluate the surgical outcomes of olfactory groove meningioma with bicoronal sub frontal approach but without orbital osteotomies.Materials and Methods:The study was performed by reviewing the medical charts, neuroimaging data, and follow-up data of 19 patients who were treated micro surgically for olfactory groove meningioma without orbital osteotomies in our department. Mean overall follow up period of our study was 5 years. Statistical analysis was done by means of IBM SPSS Software version 19.Results:Nineteen patients (1 male and 18 female patients, with an age range of 35-67 years; average age of patients' 51±7.5 years) of OGM were managed in our department. All patients were evaluated by MRI Brain with and without Gadolinium, CTA, CT Scan both axial and Coronal sequences. Most common symptom reported was head ache (80%), others include; urinary incontinence (26%), seizures (78%), decreased visual acuity (79%), papilledema (74%), personality changes (68%) and olfactory loss was reported in 57% of the patients. Post-operative complications include; CSF accumulation (5%), hematoma at tumor bed (10%), skin infection (5%) and mild post-operative brain edema (26%). Mortality rate was 5%. During 5 years of follow-up, we recorded one recurrence which was after 26 months and successfully removed in reoperation.Conclusion:Bi-coronal sub frontal approach appears to be an excellent technique for Olfactory Meningioma removal as practiced by most neurosurgeons. Nevertheless, it is not mandatory to carry out orbital osteotomy to acquire optimal surgical outcome as is advocated by some Authors.

Lateral supraorbital approach for microsurgical resection of olfactory groove meningiomas

Objective To investigate the safety and efficacy of the application of lateral supraorbital (LSO) approach for microsurgical resection of olfactory groove meningiomas. Methods Between January 2013 and December 2016, 20 patients with olfactory groove meningiomas underwent surgery through LSO approach at Department of Neurosurgery, the Second Affiliated Hospital of Zhejiang University School of Medicine. Their clinical data, surgical treatment and outcomes were analyzed retrospectively. Neuroradiological findings, improvement of symptoms and some relevant evaluation scales were used to assess the efficacy and safety of LSO for resection of olfactory groove meningiomas. Results Six patients had Simpson grade Ⅰ resection, 12 had Simpson grade Ⅱ grade resection and 2 had Simpson grade Ⅳ resection. The mean operation time was 204.8±77.4 min and the mean intraoperative blood loss was 192.5±109.2 ml. Four patients developed fever post operation, 1 had psychiatric symptoms, 1 had disturbance of consciousness, 1 had cerebral edema, and 1 developed seizure. No incision infection or cerebrospinal fluid rhinorrhea occurred. Post surgery, 2 out of 8 patients with preoperative impairment of olfactory function obtained symptomatic improvement. Among the 4 patients with vision impairment, 2 achieved improvement, 1 remained the same and 1 reported aggravation. During the follow-up of 19 patients lasting 3-40 months with an average of 16.4±9.7 months, favorable outcomes were reported in 16 cases, severe disability in 1 and tumor recurrence in 2. There was no death. Conclusion Microsurgery through LSO approach demonstrates advantages in resection of olfactory groove meningiomas including shorter operative duration, less invasiveness, and low morbidity and mortality, which is thus worthy of recommendation. Key words: Meningioma; Microsurgery; Lateral supraorbital approach; Treatment outcome

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

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). 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. 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. 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.

Unilateral Endonasal Transcribriform Approach with Septal Transposition for Olfactory Groove Meningioma: Can Olfaction Be Preserved?

Background: Loss of olfaction has been considered inevitable in endoscopic endonasal resection of olfactory groove meningiomas. The concept of olfaction preservation may be feasible through an endonasal unilateral transcribriform approach with septal transposition and contralateral preservation of the olfactory apparatus.

Unilateral endonasal transcribriform approach with septal transposition for olfactory groove meningioma: can olfaction be preserved?

Loss of olfaction has been considered inevitable in endoscopic endonasal resection of olfactory groove meningiomas. Olfaction preservation may be feasible through an endonasal unilateral transcribriform approach, with the option for expansion using septal transposition and contralateral preservation of the olfactory apparatus. An expanded unilateral endonasal transcribriform approach with septal transposition was performed in five cadaver heads. The approach was applied in a surgical case of a 24 × 26-mm olfactory groove meningioma originating from the right cribriform plate with partially intact olfaction. The surgical approach offered adequate exposure to the anterior skull base bilaterally. The nasal/septal mucosa was preserved on the contralateral side. Gross total resection of the meningioma was achieved with the successful preservation of the contralateral olfactory apparatus and preoperative olfaction. Six months later, the left nasal cavity showed no disruption of the mucosal lining and the right side was at the appropriate stage of healing for a harvested nasoseptal flap. One year later, the preoperative olfactory function was intact and favorably viewed by the patient. Objective testing of olfaction showed microsomia. Olfaction preservation may be feasible in the endoscopic endonasal resection of a unilateral olfactory groove meningioma through a unilateral transcribriform approach with septal transposition and preservation of the contralateral olfactory apparatus.