Skull Base Lesions Research Articles

Frontal trans-sinusal approach: how I do it.

Anterior skull base lesions could be reached by different approaches (subfrontal, pterional, interhemispheric, etc.). In selected cases, the frontal trans-sinusal approach is an effective alternative to conventional techniques. We present our technique to perform a frontal trans-sinusal approach in a patient affected by a large olfactory groove meningioma. The frontal trans-sinusal approach allows to approach safely lesions of the median anterior cranial fossa. This approach provides lower brain retraction, easier access to olfactory grooves, and earlier tumor devascularization. However, it remains limited to patients with large-sized frontal sinuses and entails some postoperative risks such as mucocele or CSF leak.

A multicenter retrospective analysis of clinical outcomes of intracranial chondrosarcoma in 26 patients

Intracranial chondrosarcoma is a rare tumor with limited reports. We reviewed the clinical outcomes, imaging findings, and pathological characteristics at three centers to improve the diagnosis and treatment of intracranial chondrosarcoma. We retrospectively analyzed 26 patients with intracranial chondrosarcoma who had undergone surgical treatment at Tangdu Hospital of Air Force Military Medical University, Mianyang Central Hospital, and Nanchong Central Hospital from January 2010 to July 2022. Clinical manifestations, imaging features, surgical treatment, prognosis, and overall survival (OS) were analyzed. All 26 chondrosarcomas were located at the skull base. Gross total resection (GTR), subtotal resection (STR), and partial resection (PR) were performed in 14, 10, and 2 cases, respectively. Four cases underwent endoscopic transnasal surgery, while the remaining cases underwent craniotomy. The clinical symptoms were evaluated 1 week after surgery, and 15 cases were relieved to varying degrees. Postoperative complications included pulmonary infection, subcutaneous hydrops, dysphagia and choking, facial numbness, abducens paralysis, and intracranial infection (ICI). Fifteen cases received postoperative adjuvant radiotherapy. Seven cases showed recurrence: two with PR, four with STR, and one with GTR. Six cases received reoperation or radiotherapy after tumor progression, and one untreated patient died 5 months after tumor recurrence. The extent of tumor resection (HR 21.74, 95% CI 1.25–376.6, P = 0.03) and pathological grading (HR 131.99, 95% CI 4.05–4300.5, P = 0.006) were associated with improved OS. We presented our experience in the treatment of intracranial chondrosarcoma at three centers in the past 12 years. Intracranial chondrosarcoma lacked typical imaging features and are difficult to differentiate from other skull base lesions. Maximum extent of tumor resection with minimal injury to neurological function remains the most important treatment strategy. The extent of surgical resection and pathological grading were found to be predictors for OS.

Evaluation of endocrinological sequelae following particle therapy performed on anterior skull base lesions in the adult population.

Radiotherapy has increasingly assumed a central role in the multidisciplinary treatment of skull base lesions. Unfortunately, it is often burdened by relevant radio-induced damage to the pituitary function and the surrounding structures and systems. Patients who were treated with radiotherapy around the sellar region especially have a high risk of developing radio-induced hypopituitarism. Particle therapy has the potential advantage of delivering a higher radiation dose to the target while potentially sparing the sellar region and pituitary function. The aim of this study is to evaluate the pituitary function in adult patients who have undergone hadron therapy for anterior skull base lesions involving or surrounding the pituitary gland. This is a retrospective, observational, and noncontrolled study. We evaluated pituitary and peripheral hormone levels in all patients referring to National Center for Oncological Hadrontherapy, Pavia, Italy for anterior skull base tumors. Furthermore, we performed a magnetic resonance imaging for every follow-up to evaluate potential tumoral growth. We evaluated 32 patients with different tumoral lesions with a mean follow-up of 27.9 months. The mean hadron therapy (HT) dose was 60 ± 14 Gray, with a mean dose per fraction of 2.3 ± 2.1 Gray. Six patients were treated with carbon ions and 26 with protons. Pituitary hormone alteration of some kind was reported for six patients. No patient experienced unexpected severe adverse events related to particle therapy. Particle radiotherapy performed on anterior skull base lesions has proved to cause limited damage to pituitary function in the adult population.

Image-Guided Biopsies of Superficial and Deep Head and Neck and Skull-Base Lesions.

Percutaneous image-guided biopsy has largely replaced open surgical biopsies for many head and neck (H&N) lesions, being very safe and minimally invasive. Although the radiologist plays the primary role in these cases, it requires a multidisciplinary approach. Depending upon numerous factors, these biopsies can be either fine-needle aspiration or core needle biopsy, using ultrasound for superficial lesions and computed tomography for deep neck lesions. The most crucial part of H&N biopsies is planning a trajectory to avoid injury to critical anatomic structures. This article outlines the standard biopsy approaches and key anatomical considerations for H&N procedures.

Leukocyte- and platelet-rich fibrin in endoscopic endonasal skull base reconstruction: study protocol for a multicenter prospective, parallel-group, single-blinded randomized controlled non-inferiority trial

BackgroundRecent advances in endoscopic endonasal transsphenoidal approaches (EETA) for skull base lesions have resulted in a significant increase in extent and complexity of skull base defects, demanding more elaborate and novel reconstruction techniques to prevent cerebrospinal fluid (CSF) leakage and to improve healing. Currently, commercially available fibrin sealants are often used to reinforce the skull base reconstruction. However, problems have been reported regarding hypersensitivity reactions, efficacy, and costs. This trial aims to investigate autologous leukocyte- and platelet-rich fibrin (L-PRF) membranes as an alternative for commercially available fibrin glues in EETA-related skull base reconstruction reinforcement.Methods/designThis multicenter, prospective randomized controlled trial aims to demonstrate non-inferiority of L-PRF membranes compared to commercially available fibrin sealants in EETA cases (1) without intra-operative CSF-leak as dural or sellar floor closure reinforcement and (2) in EETA cases with intra-operative CSF-leak (or very large defects) in which a classic multilayer reconstruction has been made, as an additional sealing. The trial includes patients undergoing EETA in three different centers in Belgium. Patients are randomized in a 1:1 fashion comparing L-PRF with commercially available fibrin sealants. The primary endpoint is postoperative CSF leakage. Secondary endpoints are identification of risk factors for reconstruction failure, assessment of rhinological symptoms, and interference with postoperative imaging. Additionally, a cost-effectiveness analysis is performed.DiscussionWith this trial, we will evaluate the safety and efficacy of L-PRF compared to commercially available fibrin sealants.Trial registrationClinicalTrials.gov NCT03910374. Registered on 10 April 2019.

A rare case of temporal bone chondrosarcoma

A rare case of lateral skullbase lesion, in a 24-year female, presented with moderately severe conductive type hearing loss, and facial paralysis. Audiological and radiological investigations were done which could not provide a reasonably certain diagnosis. So the patient was taken up for surgery. A subtotal pertrosectomy with blind sac closure was done. The histopathological analysis showed the lesion to be moderately differentiated chondrosracoma, an osseocartilagenous malignancy of the temporal bone. Due to rare nature, difficult location near vital structures, local invasiveness and potential for complications, diagnosis and treatment is difficult.

Imaging of Skull Base Tumors.

The skull base provides a platform for supporting the brain while serving as a conduit for major neurovascular structures. In addition to malignant lesions originating in the skull base, there are many benign entities and developmental variants that may simulate disease. Therefore, a basic understanding of the relevant embryology is essential. Lesions centered in the skull base can extend to the adjacent intracranial and extracranial compartments; conversely, the skull base can be secondarily involved by primary extracranial and intracranial disease. CT and MRI are the mainstay imaging methods and are complementary in the evaluation of skull base lesions. Advances in cross-sectional imaging have been crucial in the management of patients with skull base pathology, as this represents a complex anatomical area that is hidden from direct clinical exam. Furthermore, the clinician must rely on imaging studies for therapy planning and to monitor treatment response. It is crucial to have a thorough understanding of skull base anatomy and its various pathologies, as well as to recognize the appearance of treatment-related changes. In this review, we aim to describe skull base tumors and tumor-like lesions in an anatomical compartmental approach and present imaging methods that aid in diagnosis, management, and follow-up.

Endoscopic Transorbital Approach for Spheno-Orbital Tumors: Case Series and Systematic Review of Literature

Transorbital neuroendoscopic surgery (TONES) comprises a group of approaches with indications expanding from orbital tumors to more complex skull base lesions. We analyzed the role of the endoscopic transorbital approach (eTOA) for spheno-orbital tumors, reporting the results of our clinical series and of a systematic review of the literature. All patients operated on from 2016 to 2022 at our institution for a spheno-orbital tumor through an eTOA were included in a clinical series, and a systematic review of the literature was performed. Our series consisted of 22 patients (16 females, mean age 57 ± 13 years). Gross tumor removal was achieved in 8 patients (36.4%) after the eTOA and in 11 (50.0%) after a multistaged strategy combining the eTOA with the endoscopic endonasal approach. Complications included 1 chronic subdural hematoma and 1 permanent extrinsic ocular muscle deficit. Patients were discharged after 2.4 ± 1.3 days. The most common histotype was meningioma (86.4%). Proptosis improved in all cases, visual deficit in 66.6%, and diplopia in 76.9%. These results were confirmed by the review of the 127 cases reported in the literature. Despite its recent introduction, a significant number of spheno-orbital lesions treated with an eTOA are being reported. Its main advantages are favorable patient outcome and optimal cosmetic results, with minimal morbidity and quick recovery. This approach can be combined with other surgical routes or adjuvant therapies for complex tumors. However, it is a technically demanding procedure, requiring specific skills in endoscopic surgery, that should be reserved to dedicated centers.

Prevalence of Anatomical Variations of Sphenoid Sinus and Its Adjacent Structures Pneumatization and Its Significance: A CT Scan Study.

The purpose of our study was to assess the prevalence of variations and type of sphenoid sinus and its adjacent structures pneumatization and its significance. This prospective study included 114 patients who underwent CT of the paranasal sinuses. The CT scan in axial, coronal and mid sagital section were analysed to assess the type of pneumatization of the sphenoid sinus and its adjacent structures like; anterior clinoid process, greater wing of sphenoid and pterygoid process. The sphenoid sinus pneumatization was classified into Conchal, Presellar, and Sellar types, later comprised of sellar and post-sellar types. Out of 114 cases of pneumatized sphenoid sinus, 5.2% cases were conchal type, 26.3% cases Presellar type and 68.4% cases sellar type. The one or more adjacent structures was pneumatized in 71 (62.2%) of cases. The adjacent structures which found to be pneumatized are anterior clinoid process in 26.3%, Pterygoid process in 23.6%, and greater wing of sphenoid in 12.3% cases. The pneumatization of adjacent structures was more prevalent in sellar type of sphenoid sinus, followed by pre-sellar type and no pneumatization in conchal type. The anterior clinoid process pneumatization was present in 26.1% of cases, in which 3 (2.6%) cases in pre-sellar type and 27 (23.5%) cases in sellar type. It was unilaterally pneumatized in 13 (11.4%) and bilaterally in (17 (14.9%) cases. The pterygoid process pneumatization was present in 27 (23.6%) of cases, unilateral in 16 (14%) cases and bilateral in 11 (9.6%) cases. The Greater wing of sphenoid pneumatization was found in 14 (12.3%) cases, no cases in conchal types, 2 (1.8%) in pre-sellar type, and 12 (10.4%) in sellar type There was no statistically difference found in between right and left side of sphenoid sinus and its structure pneumatization. The extent of pneumatization of the sphenoid sinus has clinical and surgical implications in sinus diseases, sellar and central skull base lesions.

P.086 Unusual case of Aspergillosis presenting as a skull base lesion

Background: Fungi are ubiquitous microorganisms. Sinonasal fungal infections range from an acute fulminant to a chronic indolent clinical course. Fungal infections are common in immunocompromised patients, diabetics, and those with hematological malignancies. We present an unusual case of chronic invasive fungal sinusitis presenting as an anterior skull base lesion. Methods: A 42-year-old patient was referred with a history of right-sided proptosis. Prompt CT and MR imaging revealed a large right sinonasal erosive mass, predominantly T2 hypointense with heterogeneous enhancement. It extended into the right anterior skull base and invaded the right frontal lobe. The mass also invaded into the right extra-conal orbital fat, right pterygopalatine fossa, and right sphenopalatine foramen. Results: In view of the imaging findings, a biopsy was performed which confirmed fungal elements and chronic inflammation. Subsequently, a right-sided endoscopic endonasal resection of the sinonasal mass with resection of the right orbital component and debulking of the anterior skull base component was performed. Culture specimen grew aspergillosis. Conclusions: Extra-sinus invasion in fungal sinusitis is not uncommon. These cases may mimic other pathologies, e.g., tumors, with potential delay in treatment. Sound knowledge of the imaging appearances of this entity is imperative to ensure a good outcome.

Transorbital neuroendoscopy-assisted resection of a giant optic pathway glioma in a neonate.

Congenital giant orbital tumors in infancy are relatively rare, especially when the tumors are associated with significant intracranial extension. We describe the use of a transorbital neuroendoscopy-assisted resection of such a lesion. While this approach is increasingly gaining popularity for certain anterior and middle skullbase lesions in adults, this report represents the youngest patient reported on where this minimally invasive approach has been successfully used to resect the intracranial tumor. This surgical approach obviated the need for a separate craniotomy, with the additional benefit of minimizing blood loss.

A giant invasive macroprolactinoma with recurrent nasal bleeding as the first clinical presentation: case report and review of literature

BackgroundGiant prolactinoma (> 4 cm in dimension) is a rare disorder. Invasive macroprolactinoma has the potential to cause base of skull erosion and extend into the nasal cavity or even the sphenoid sinus. Nasal bleeding caused by intranasal tumor extension is a rare complication associated with invasive giant prolactinoma.We report a case of giant invasive macroprolactinoma with repeated nasal bleeding as the initial symptom.Case presentationA 24-year-old man with an invasive giant prolactinoma in the nasal cavity and sellar region who presented with nasal bleeding as the initial symptom, misdiagnosed as olfactory neuroblastoma. However, markedly elevated serum prolactin levels (4700 ng/mL), and a 7.8-cm invasive sellar mass confirmed the diagnosis of invasive giant prolactinoma. He was treated with oral bromocriptine. Serum prolactin was reduced to near normal after 6 months of treatment. Follow-up magnetic resonance imaging showed that the sellar lesion had disappeared completely and the skull base lesions were reduced.ConclusionThis case is notable in demonstrating the aggressive nature of untreated invasive giant prolactinomas which can cause a diagnostic difficulty with potential serious consequences. Early detection of hormonal levels can avoid unnecessary nasal biopsy. Early identification of pituitary adenoma with nasal bleeding as the first symptom is particularly important.

Chronic cerebrospinal fluid rhinorrhea as an initial presentation of chordoma: illustrative case.

Skull base chordomas are typically extradural and present with cranial nerve deficits, headache, and visual disturbances. Clival chordoma involving the dura and presenting as a spontaneous cerebrospinal fluid (CSF) leak is extremely rare and can be mistaken for other skull base lesions. Here the authors present a case of chordoma with an unusual presentation. A 43-year-old female who presented with clear nasal drainage was diagnosed with CSF rhinorrhea secondary to a clival defect previously thought to be ecchordosis physaliphora. The patient subsequently developed bacterial meningitis and underwent endoscopic, endonasal, transclival gross-total resection of the lesion with repair of the dural defect. Pathology revealed brachyury-positive chordoma. She received adjuvant proton beam radiotherapy and has remained stable for 2 years. Spontaneous CSF rhinorrhea can occur as a rare primary presentation of clival chordoma, requiring careful radiological interpretation and a high index of suspicion for diagnosis. Chordoma cannot be reliably differentiated from benign notochordal lesions based on imaging alone; thus, intraoperative exploration and immunohistochemistry play key roles. Clival lesions presenting with CSF rhinorrhea should undergo prompt resection to facilitate diagnosis and prevent complications. Future studies on connections between chordoma and benign notochordal lesions may help to establish management guidelines.

Application of Radiomics to the Differential Diagnosis of Temporal Bone Skull Base Lesions: A Pilot Study.

Temporal bone skull base pathologies represent a complex differential because they can be radiographically obscure and difficult to diagnose without biopsy. Radiomics involves the use of mathematical quantification of imaging data beyond simple intensity, size, and location to inform diagnosis and prognosis. We examined the feasibility of using radiomic parameters to help predict temporal bone tumor type. A total of 117 radiomic parameters were analyzed from 5 magnetic resonance imaging sequences (T1 without contrast, T1 with contrast, T2, fluid-attenuated inversion recovery, apparent diffusion coefficient [ADC]) for each tumor. Statistical analysis was used to delineate known primary, metastatic/secondary, and lymphoma lesions using radiomics. The mean tumor volumes for the 14 primary, 12 secondary, and 8 lymphoma lesions were 2.98 ± 2.11, 3.28 ± 2.31, and 12.16 ± 7.1cm3, respectively (P= 0.2). No significant differences in mean intensity values for any sequence helped distinguish tumors (P > 0.05), but 6 radiomic parameters were significantly correlated with diagnostic accuracy. Discriminant analysis using a stepwise algorithm generated a model where radiomic parameters for T1 cluster prominence, ADC dependence nonuniformity, T1 with contrast zone percentage, and ADC informational measure of correlation 2 achieved the best predictive model (P= 0.0001). These significant characteristics were often indirect measures of tumor heterogeneity on different magnetic resonance imaging sequences. These data suggest that quantitative measures of tumor heterogeneity can be discriminatory of pathology and might be integrated into clinical workflow. Although this pilot study requires further validation, these data support the exploration of radiomics in temporal bone radiographic diagnostics.

Feasibility and Morbidity for the Use of MR-Guided Laser-Induced Thermotherapy for the Treatment of Skull Base Tumors: A Report of Three Cases

Background Laser-induced thermotherapy (LITT) is a minimally invasive technique that has been demonstrated as an effective treatment of many pathologies; however, it has never been investigated for the use in skull base tumors. Case Series Three patients underwent LITT for treatment of skull base meningiomas. All three patients were determined to be poor candidates for open resection. Each patient was treated with a single laser fiber. Postoperative imaging confirmed ablation zones along the tract of the catheter in all three patients. Ablation zones were estimated to be 9 to 20% of the intended to treat tumor volume. Two of three treated patients suffered cranial nerve injury following the procedure with one patient diagnosed with neurotrophic keratitis and one patient with symptoms consistent with anesthesia dolorosa. Conclusion LITT is a technically feasible, minimally invasive treatment modality for skull base lesions. Significant risk to cranial nerves and small ablation zones afforded by a single cannula placement proposes serious obstacles. Further investigation is warranted prior to using this technique outside of a palliative indication.

Endoscopic transorbital approach for skull base lesions: a report of 16 clinical cases.

Due to the deep location, complex anatomy, and adjacent vital neurovascular structures, skull base surgery is challenging and requires specific approaches. The emerging endoscopic transorbital approach (eTOA) technique provides a new approach to the orbital content, spheno-orbital region, lateral cavernous sinus, and Meckel's cave. In this study, the clinical utility and effectiveness of the eTOA are reported. Sixteen cases who underwent the eTOA were included in the current study. The patients were divided into 3 groups according to tumor location: Group A (intraorbital, 6 cases), group B (spheno-orbital, 7 cases), and group C (cavernous sinus, and Meckel's cave, 3 cases). The clinical data and surgical results were analyzed. Eight meningiomas, 2 hemangiomas, 1 low-grade glioma, 1 instance of inflammatory hyperplasia tissue, 1 Langerhans cell histiocytosis, 1 epidermoid cyst, 1 trigeminal schwannoma, and 1 bone fibrosis hyperplasia were observed. The mean tumor diameter was 2.4cm. A single case in Group A and Group C underwent biopsy (12.5%), and 1 case of fibrous dysplasia in Group B underwent sufficient orbit decompression (6.25%). The remaining 13 cases underwent gross total tumor resection (81.25%). No cerebral-spinal fluid leak or infection occurred. And no cosmetic problems or significant complications were observed during the follow-up. As a minimally invasive technique, the eTOA has unique advantages for carefully selected skull base lesions because of its direct route, short working distance, and distinct attack angle.

Bilateral clinoidal Rosai Dorfman disease mimicking meningioma – a rare cause of bilateral blindness

Rosai Dorfman disease is a self-limiting disease usually affecting the lymph nodes. Intracranial lesions are seen in less than 5% of cases. Isolated intracranial RDD without nodal involvement is rare, only 70 cases have been reported to date. Skull base lesions are seen in only 7 cases, petro clival RDD. Clionoidal lesions of RDD have not been reported in the literature, we report a rare case of bilateral Clionoidal lesions of RDD presenting with bilateral blindness in a young male.

Staged Open Cranial Surgery for Primary Intra-axial Neoplasms: A Systematic Review

Staged surgery for skull base lesions has been utilized to facilitate maximal safe resection and optimize outcomes while minimizing morbidity and complications. Conversely, staged surgery for primary intraparenchymal neoplasms is less commonly performed and has not been reported as extensively within the literature. As such, we performed a systematic review to examine the unique surgical indications for staging, timing between stages, specific surgical approaches utilized, and postoperative complications of staged surgery for primary intra-axial neoplasms. A literature search was conducted in August 2021 using PubMed, Web of Science, and Cochrane databases using the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) recommendations. Titles and abstracts were evaluated independently by 2 authors, after which articles were selected for final analysis based on application of strict inclusion criteria during full text screen. Each included article was then qualitatively assessed and relevant variables-including operative approaches, timing, and outcomes-were extracted for synthesis. Of 115 results, 7 articles were included for final analysis and consisted of 17 pediatric and 4 adult patients. Staged approaches were more commonly utilized in the pediatric patient population for resection of astrocytoma and glioma. Pediatric patients had a timing of surgeries ranging from 5-10 days between operations, compared with 18 days to 4 months in adult patients. Complications in pediatric patients were most commonly hemiparesis, hydrocephalus, cranial nerve VI and VII palsies, truncal ataxia, and cerebellar mutism, while complications in adult patients included language and abstract thinking deficits, respiratory failure, and motor weakness. This study reports the first comprehensive review of staged surgical procedures for primary, intra-axial cranial neoplasms. There exists a large degree of heterogeneity in complications resulting from staged surgeries for intra-axial neoplasms, which are similar to complications associated with single-stage surgery for intraparenchymal lesions as well as multi-stage surgeries for skull base lesions.

Transorbital approach for resection of intracranial skull base lesions: Outcomes and complications

IntroductionThe transorbital approach has emerged in recent years as a minimally invasive corridor for accessing intracranial skull base lesions. We reviewed our experience developing a multidisciplinary superior eyelid transorbital technique to further elucidate the indications, and clinical outcomes of this novel approach. MethodsRetrospective single-center chart review of patients undergoing microscopic transorbital resection of skull base lesions via a superior eyelid or suprabrow incision was completed. Comparisions between neurologic, opthamologic, and cosmetic outcomes of those undergoing surgery in the first two years of adopting the technique versus the last two years were completed. R-studio and descriptive statistics were used for analysis. ResultsForty patients (33 % male) underwent transorbital surgery from 2017 to 2021. Postoperatively, 72 % experienced symptom stability or improvement. No patients demonstrated mild decline in visual acuity (>0.5 LogMAR “the logarithm of the minimum angle of resolution” decrease) on long-termfollow-up and there was no significant change in overall visual acuity from pre-op to post-op in all patients.Early postoperative complications included infection, seizure, and hematoma, with an overall complication rate of 7.5 %. In the most recent year, there have been no significant postoperative complications, or need for additional cosmetic procedures in 21 patients. There have been no cerebrospinal fluid leaks throughout all the years of practice. ConclusionThe superior eyelid transorbital approach provides an innovative minimally invasive corridor for a variety of middle fossa, anterior skull base, andsellarregion pathologies. Multidisciplinary collaboration has allowed us to develop this technique over time, minimize complications, and allow for good cosmetic and clinical outcomes.

Neurovascular structures in the lateral recess of the sphenoid sinus. A computed tomography evaluation

Introduction and objectivesAnatomical variations of the lateral recess of the sphenoid sinus and its relations with the adjacent neurovascular structures should be preoperatively evaluated to plan an adequate surgical approach and avoid iatrogenic injuries. This study aims to analyze the patterns of pneumatization of the lateral recess of the sphenoid sinus and their association with the presence of protrusion and dehiscence of the optic canal, carotid canal, vidian canal, and maxillary nerve. Materials and methodsA retrospective evaluation of 320 sphenoid sinuses by computed tomography was performed. Studied variables included type of lateral recess, and protrusion, and dehiscence of the optic and carotid canal, and vidian and maxillary nerve. ResultsThe mean age was 45.67±17.43. A total of 55.6% (n=178) of the evaluated sphenoid sinuses corresponded to male subjects. Protrusion of the carotid canal, maxillary nerve, and vidian canal was associated with a type 3 lateral recess pneumatization, while dehiscence of these structures was most commonly observed in a type 2 lateral recess (p=<0.001). ConclusionsProtrusion or dehiscence of neurovascular structures surrounding the sphenoid sinus has been associated with the extent of pneumatization of the lateral recess, increasing the risk of intraoperative injury. Preoperative identification of anatomical variations is mandatory to select the best approach for skull base lesions and avoid iatrogenic injuries.