Olfactory Groove Research Articles

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.

Endoscope-assisted transcranial surgery for anterior skull base meningiomas

Anterior skull base meningiomas are benign, dural-based tumors that originate from the tuberculum sellae, planum sphenoidale or olfactory groove. A multitude of traditional transcranial approaches have been effectively used for resection of these tumors. However, in the era of minimally invasive neurosurgery, the endoscopic endonasal and the endoscope-assisted or endoscope-controlled supraorbital keyhole eyebrow approaches stand out as the two main options utilized to resect these tumors. The supraorbital keyhole approach minimizes brain retraction, tissue dissection and length of the skin incision. Consequently, this approach is associated with a lower complication profile and much better cosmetic results in comparison to classic approaches. With endoscopic assistance or control, the approach provides an excellent view of anterior skull base meningiomas and enables optic nerve decompression when angled scopes are used. In our opinion, endoscopes will ultimately replace the surgical microscopes as the viewing tools in this type of surgery. A limited number of studies have directly compared the endoscopic endonasal approach versus the supraorbital keyhole one for resection of anterior cranial base meningiomas. In these studies, scores and algorithms have been suggested to help select the suitable approach. The practical value of these algorithms still needs to be validated by further research. Although the endoscope-assisted or -controlled supraorbital keyhole approach offers a minimally invasive and highly effective approach for excision of anterior cranial base meningiomas, the ideal approach should be tailored to the individual patient according to the tumor size, lateral extension, optic canal involvement, extent of vascular encasement and surgeon’s experience.

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.

Primary Repair of Posteriorly Located Anterior Skull Base Dural Defects Using Nonpenetrating Titanium Clips in Cranial Trauma.

Objective Primary repair of posteriorly located anterior skull base (ASB) dural defects following cranial trauma is made difficult by narrow operative corridors and adherent dura mater. Inadequate closure may result in continued cerebrospinal fluid (CSF) leak and infectious sequelae. Here, we report surgical outcomes following the use of nonpenetrating titanium microclips as an adjunctive repair technique in traumatic anterior skull base dural defects extending from the olfactory groove to the tuberculum sellae. Methods All trauma patients who underwent a bifrontal craniotomy from January 2013 to October 2019 were retrospectively reviewed. Patients with ASB defects located at posterior to the olfactory groove were analyzed. Patients with isolated frontal sinus fractures were excluded. All patients presented with CSF leak or radiographic signs of dural compromise. Patients were divided according to posterior extent of injury. Patient characteristics, imaging, surgical technique, and outcomes are reported. Results A total of 19 patients who underwent a bifrontal craniotomy for repair of posteriorly located ASB dural defects using nonpenetrating titanium microclips were included. Defects were divided by location: olfactory groove (10/19), planum sphenoidale (6/19), and tuberculum sellae (3/19). No patients demonstrated a postoperative CSF leak. No complications related to the microclip technique was observed. Clip artifact did not compromise postoperative imaging interpretation. Conclusion Primary repair of posteriorly located ASB dural defects is challenging due to narrow working angles and thin dura mater. Use of nonpenetrating titanium microclips for primary repair of posteriorly located dural defects is a reasonable adjunctive repair technique and was associated with no postoperative CSF leaks in this cohort.

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

Simple SummaryResectioning 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.(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.

A minimally invasive supraorbital keyhole approach through superciliary arch for giant olfactory Groove angiopericytoma: case report

Hemangiopericytoma of the central nervous system, also known as vascular pericytes tumor, which is a rare mesenchymal...

Regional Recurrences and Hyams Grade in Esthesioneuroblastoma.

Objective The aim of this study is to determine if Hyams grade may help predict which patients with esthesioneuroblastoma (ENB) tumors are likely to develop regional recurrences, and to determine the impact of tumor extent on regional failure in ENB patients without evidence of nodal disease at presentation. Design The study was designed as a retrospective review for ENB patients. Settings The study was prepared at tertiary care academic center for ENB patients. Participants Patients with ENB were included in the study. Main Outcome Measures Oncologic outcomes (5-year regional and locoregional control (LRC) and overall survival) in patients with Hyams low grade versus high grade. Oncologic outcomes based on radiographic disease extent. Results A total of 43 patients were included. Total 25 patients (58%) had Hyams low-grade tumor, and 18 (42%) had high-grade tumor. Of the 34 patients without regional disease at presentation, 8 (24%) were treated with elective nodal radiation. There were no statistically significant differences in 5-year regional control in the Hyams low-grade versus high-grade groups (78 vs. 89%; p = 0.4). The 5-year LRC rates in patients with low grade versus high grade were 73 versus 89% ( p = 0.6). The 5-year overall survival rates in patients with low-grade versus high-grade tumors were 86 versus 63% ( p = 0.1). Radiographic extension of disease into the olfactory groove, olfactory nerve, dura, and periorbita were statistically associated with decreased 5-year overall survival (5-year OS 49 vs. 91% [ p = 0.04], 49 vs. 91% [ p = 0.04], 44 vs. 92% [ p = 0.02], and 44 vs. 80% [ p = 0.04], respectively). Conclusion ENBs are associated with a risk of regional failure. The current analysis suggests that Hyams low-grade and high-grade malignancies have comparable rates of early and delayed regional recurrences, although small sample size may limit our conclusions.

Detailed Arterial Anatomy and Its Anastomoses of the Sphenoid Ridge and Olfactory Groove Meningiomas with Special Reference to the Recurrent Branches from the Ophthalmic Artery.

Detailed arterial anatomy of the sphenoid ridge and olfactory groove meningiomas is complicated due to the fine angioarchitecture and anastomoses between each feeder. Herein, we present details of the arterial anatomy and the relationships of feeders in these lesions. This study included 20 patients admitted to our department between April 2015 and March 2020. Conditions of subjects consisted of 16 sphenoid ridge meningiomas and 4 olfactory groove meningiomas. We mainly analyzed arterial anatomy using 3D rotational angiography and slab MIP images of these lesions. We also analyzed the anastomoses of each feeder. We found that 19 (95%), 15 (75%), and 15 (75%) lesions had feeders from the ophthalmic, internal carotid, and external carotid arteries, respectively. As feeders from the ophthalmic artery, recurrent meningeal arteries were involved in 18 lesions (90%). Fifteen lesions (75%) had anastomoses between each feeder. Most of the meningiomas in the sphenoid ridge and olfactory groove had feeders from the ophthalmic and internal carotid arteries. There were various anastomoses between each feeder. This is the first report to demonstrate the detailed arterial anatomy and frequency of recurrent branches from the ophthalmic artery and their anastomoses using detailed imaging techniques.

Endoscopic Endonasal Resection-Olfactory Groove Meningioma: 2-Dimensional Operative Video.

Olfactory groove meningiomas can represent a surgical challenge, and controversy persists in regard to the optimal approach corridor.1,2 This video exemplifies the endoscopic endonasal resection of a voluminous olfactory groove meningioma. Focus is given on the key aspects of the procedure, complication avoidance, nuances of the technique, and advantages pertaining to this approach.3-6 The patient consented for the conception and publication of this video.

Microsurgical Excision of Olfactory Groove Meningiomas, Comparative Studies of Different Surgical Approaches

Introduction: To review the surgical approaches, techniques, outcomes and recurrence rates in a series of 11 olfactory groove meningioma (OGM) patients operated from January 2010 to April 2019. Methods: Eleven patients underwent craniotomy and micro-neurosurgical removal of olfactory groove meningioma. Tumor diameter varied from 5 to 8.5 cm among 11 cases, 2 cases underwent Transglabellar/ Subcranial approach, 3 cases by bifrontal approach, 1 case unifrontal approach, 2 extended endonasal and 3 cases fronto-lateral approach. Result: Total removal was possible in all cases except 2 cases. Histopathology revealed typical meningioma (WHO grade 1). There was 1 operative mortality and no permanent focal neurological deficit except anosmia. 3 patients developed CSF leak and two cases meningitis which were resolved by lumber drain and antibiotic therapy. Conclusion: Extended endonasal approach or transglabellar/ subcranial approach were sufficient for gross total removal of OGM which is associated with bony hyperostosis, paranasal extension and optic canal. Bang. J Neurosurgery 2020; 10(1): 9-19

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

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

MR imaging in Kallmann syndrome: a case report

BackgroundA rare genetic disorder called Kallmann syndrome results from a defect in the neuronal migration of olfactory axons and gonadotropin-releasing hormone neurons. MR imaging helps in confirming the diagnosis of Kallmann syndrome with characteristic morphological findings in the brain, in clinically suspicious cases of hypogonadotropic hypogonadism with anosmia/hyposmia.Case presentationA 15-year-old male teenager presented with complaints of a small penis and anosmia. Hormonal assay of gonadotropins and testosterone revealed low serum concentrations. MRI brain revealed the absence of the olfactory bulbs in the olfactory grooves and hypoplastic olfactory sulcus. With the gonadotropic hormonal assay showing low levels and characteristic MR imaging features of absent olfactory tracts and olfactory sulcus, the diagnosis of Kallmann syndrome was confirmed.ConclusionsMorphological abnormalities of olfactory tracts and olfactory sulcus can be accurately depicted with MR imaging through anterior fossa in the coronal plane. Therefore, MR imaging of the brain plays a significant role in diagnosing uncommon Kallmann syndrome and other associated brain abnormalities.

The endoscope-assisted supraorbital \u201ckeyhole\u201d approach for anterior skull base meningiomas: an updated meta-analysis

IntroductionThe 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.MethodsAn 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.ResultsA 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.ConclusionsIn 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: case series and systematic review of extent of resection, quantification of postoperative frontal lobe injury, anosmia, and recurrence.

Olfactory groove meningiomas (OGMs) are commonly treated with open craniotomy. Endonasal approaches have also been described. To present clinical and radiographic outcomes for the minimally invasive eyebrow incision supraorbital keyhole approach with endoscopic assistance for OGMs. We performed a retrospective single-center cohort study and a systematic literature review. 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 ± 18.3cm3 preoperatively to 9.9 ± 11.4cm3 immediately postoperatively, and there was minimal new restricted diffusion (3.2 ± 2.2cm3; max 7.5cm3). Median length of stay was 3days (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 3months. After a median follow-up of 32.2months, 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. 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.

Use of endoscopic transorbital and endonasal approaches for 360° circumferential access to orbital tumors.

Orbital tumors are often surgically challenging because they require an extensive fronto-temporo-orbital zygomatic approach (FTOZ) and a multidisciplinary team approach to provide the best outcomes. Recently, minimally invasive endoscopic techniques via a transorbital superior eyelid approach (ETOA) or endoscopic endonasal approach (EEA) have been proposed as viable alternatives to transcranial approaches for orbital tumors. In this study, the authors investigated the feasibility of 360° circumferential access to orbital tumors via both ETOA and EEA. Between April 2014 and June 2019, 16 patients with orbital tumors underwent either ETOA or EEA at the authors' institution. Based on the neuro-topographic "four-zone model" of the orbit with its tumor epicenter around the optic nerve in the coronal plane, ETOA (n = 10, 62.5%) was performed for tumors located predominantly superolateral to the nerve and EEA (n = 6, 37.5%) for those located predominantly inferomedial to the nerve. Eight patients (50%) presented with intraconal tumors and 8 (50%) with extraconal ones. The orbital tumors included orbital schwannoma (n = 6), cavernous hemangioma (n = 2), olfactory groove meningioma (n = 1), sphenoorbital meningioma (n = 1), chondrosarcoma (n = 1), trigeminal schwannoma (n = 1), metastatic osteosarcoma (n = 1), mature cystic teratoma (n = 1), sebaceous carcinoma (n = 1), and ethmoid sinus osteoma (n = 1). The clinical outcomes and details of surgical techniques were reviewed. Gross-total resection was achieved in 12 patients (75%), near-total resection in 3 (18.8%), and subtotal resection in 1 (6.2%). Eight (88.9%) of the 9 patients with preoperative proptosis showed improvement after surgery, and 4 (66.7%) of the 6 patients with visual symptoms demonstrated improvement. Four (40%) of the 10 patients treated with ETOA experienced partial third nerve palsy immediately after surgery (3 transient and 1 persistent). There have been no postoperative CSF leaks or infections in this series. Without transcranial approaches requiring temporalis muscle dissection and orbitozygomatic osteotomy, the selection of ETOA or EEA based on a concept of a four-zone model with its epicenter around the optic nerve successfully provides a minimally invasive 360° circumferential access to the entire orbit with acceptable morbidity.

Giant Olfactory Groove Meningioma in Pregnancy

Introduction: Meningioma is slow growing neoplasm cells that comes from arachnoid cap most common benign intracranial tumours. Olfactory groove meningiomas (OGM) account for 8–13% of all intracranial meningiomas. Intracranial tumors on pregnancy is a rare event, with few reports. Case Presentation: A 36-year-old- female (G11P9A1) 34 gestational week presented to the Adam Malik General Hospital with smelling disturbances for 6 months and lossing smelling sense in the past 1 month. Slowly progression of vision disturbances for 3 months without improvement in using glasses, progressive loss of vision in both eyes for the past 1 month. CT scan and MRI revealead a solid mass lesion, with 6.3 x 4.2 x 3.1 cm. It was a supratentorial in frontal region, olfactory groove mass. The Craniotomy tumor removal was performed in this patient. Discussion: Meningiomas are mostly silent brain tumors with slow growth, however may get detected and mostly become symptomatic during pregnancy and luteal phase of menstrual cycle due to increase in size secondary to either water retention, enhanced vascularity or progesterones are possible etiologies. The majority of meningiomas express progesterone reseptor, which can be detected also by immunohistochemistry. In fact, tumour growth when progesterone concentrations are higher, shows the role of sex hormones in the mechanism. Regardless of the status of pregnancy, symptomatic and large meningiomas require surgical resection. Conclusion: Changes of plasma concentration hormones during pregnancy and their effect on meningioma growth in the second and third trimester are crucial and critical. The management of brain lesions during pregnancy required professional collaboration between neurosurgeons, obstetricians and anesthesiologists.

The Preferred Locations of Meningioma According to Different Biological Characteristics Based on Voxel-Wise Analysis.

Objective: Meningiomas presented preferred intracranial distribution, which may reflect potential biological natures. This study aimed to analyze the preferred locations of meningioma according to different biological characteristics.Method: A total of 1,107 patients pathologically diagnosed with meningiomas between January 2012 and December 2016 were retrospectively analyzed. Preoperative MRI were normalized, and lesions were semiautomatically segmented. The stereospecific frequency and p value heatmaps were constructed to compare two biological phenotypes using two-tailed Fisher's exact test. Age, sex, WHO grades, extent of resection (EOR), recurrence, and immunohistochemical markers including p53, Ki67, epithelial membrane antigen (EMA), progesterone receptor (PR), and CD34 were statistically analyzed. Recurrence-free survival (RFS) were analyzed by Kaplan–Meier method.Result: Of 1,107 cases, convexity (20.8%), parasagittal (16.1%), and falx (11.4%) were the most predominant loci of meningiomas. The p-value heatmap suggested lesion predominance in the left frontal and occipital convexity among older patients while in the left sphenoid wing, and right falx, parasellar/cavernous sinus, and middle fossa among younger patients. Lesions located at anterior fossa and frontal structures were more frequently seen in the male while left parietal falx and tentorial regions, and right cerebellopontine angle in the female. Grades II and III lesions presented predominance in the frontal structures compared with grade I ones. Meningiomas at the left parasagittal sinus and falx, tentorium, intraventricular regions, and skull-base structures were significantly to receive subtotal resection. Lesions with p53 positivity were statistically located at the left frontal regions and parasellar/cavernous sinus, higher Ki67 index at the left frontal and bilateral parietal convexity and right parasellar/cavernous sinus, EMA negativity at the right olfactory groove and left middle fossa, and CD34 positivity at the sellar regions and right sphenoid wing. Tumor recurrence rates for grades I, II, and III were 2.8, 7.9, and 53.8%, respectively. Inferior RFS, higher Ki67 index, grades II and III, and a larger preoperative volume were observed in older patients. Recurrent meningiomas were more frequently found at the occipital convexity, tentorium, sellar regions, parasagittal sinus, and left sphenoid wing.Conclusion: The preferred locations of meningioma could be observed according to different biological characteristics, which might be helpful for clinical decisions.

The Role of 3D Tractography in Skull Base Surgery: Technological Advances, Feasibility, and Early Clinical Assessment with Anterior Skull Base Meningiomas.

Objective The aim of this study is to determine feasibility of incorporating three-dimensional (3D) tractography into routine skull base surgery planning and analyze our early clinical experience in a subset of anterior cranial base meningiomas (ACM). Methods Ninety-nine skull base endonasal and transcranial procedures were planned in 94 patients and retrospectively reviewed with a further analysis of the ACM subset. Main Outcome Measures (1) Automated generation of 3D tractography; (2) co-registration 3D tractography with computed tomography (CT), CT angiography (CTA), and magnetic resonance imaging (MRI); and (3) demonstration of real-time manipulation of 3D tractography intraoperatively. ACM subset: (1) pre- and postoperative cranial nerve function, (2) qualitative assessment of white matter tract preservation, and (3) frontal lobe fluid-attenuated inversion recovery (FLAIR) signal abnormality. Results Automated 3D tractography, with MRI, CT, and CTA overlay, was produced in all cases and was available intraoperatively. ACM subset : 8 (44%) procedures were performed via a ventral endoscopic endonasal approach (EEA) corridor and 12 (56%) via a dorsal anteromedial (DAM) transcranial corridor. Four cases (olfactory groove meningiomas) were managed with a combined, staged approach using ventral EEA and dorsal transcranial corridors. Average tumor volume reduction was 90.3 ± 15.0. Average FLAIR signal change was -30.9% ± 58.6. 11/12 (92%) patients (DAM subgroup) demonstrated preservation of, or improvement in, inferior fronto-occipital fasciculus volume. Functional cranial nerve recovery was 89% (all cases). Conclusion It is feasible to incorporate 3D tractography into the skull base surgical armamentarium. The utility of this tool in improving outcomes will require further study.

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.

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.