Combined Endoscopic Endonasal Transclival and Contralateral Transmaxillary Approach to the Petrous Apex and the Petroclival Synchondrosis: Working "Around the Corner" of the Internal Carotid Artery-Quantitative Anatomical Study and Clinical Applications.

The endoscopic contralateral transmaxillary (CTM) approach has been proposed as a potential route to widen the corridor posterolateral to the internal carotid artery (ICA). In this study, we first refined the surgical technique of a combined multiportal endoscopic endonasal transclival (EETC) and CTM approach to the petrous apex (PA) and petroclival synchondrosis (PCS) in the dissection laboratory, and then validated its applications in a preliminary surgical series. The combined EETC and CTM approach was performed on three cadaver specimens based on four surgical steps: (1) the nasal, (2) the clival, (3) the maxillary and (4) the petrosal phases. The CTM provided a "head-on trajectory" to the PA and PCS and a short distance to the surgical field considerably furthering surgical maneuverability. The best operative set-up was achieved by introducing angled optics via the endonasal route and operative instruments via the transmaxillary corridor exploiting the advantages of a non-coaxial multiportal surgery. Clinical applications of the combined EETC and CTM approach were reported in three cases, a clival chordoma and two giant pituitary adenomas. The present translational study explores the safety and feasibility of a combined multiportal EETC and CTM approach to access the petroclival region though different corridors.

Percutaneous Vertebroplasty as the Treatment of Choice for Multiple Adjacent Lumbar Atypical Haemangiomas: A Case Report.

Atypical vertebral haemangiomas (VHs) are uncommon lesions that cause lumbar pain and motor symptoms. Current management mainly relies on radiotherapy, surgical spine decompression, or percutaneous techniques. We describe a unique case of a patient with two adjacent lumbar VHs and an underlying lumbar fracture which was treated only by percutaneous vertebroplasty (PV). The non-invasive technique relieved the patient's pain and did not affect column stability. PV may be considered an amenable pain-relieving treatment for adjacent atypical VHs in selected patients.

Single versus multiple reoperations for recurrent intracranial meningiomas.

PURPOSE: To identify the risk factors and management of the multiple recurrences and reoperations for intracranial meningiomas. METHODS: Data of a neurosurgical series of 35 patients reoperated on for recurrent intracranial meningiomas were reviewed. Analyzed factors include patient age and sex, tumor location, extent of resection, WHO grade, Ki67-MIB1 and PR expression at initial diagnosis, time to recurrence; pattern of regrowth, extent of resection, WHO grade and Ki67-MIB1 at first recurrence were also analyzed. All these factors were stratified into two groups based on single (Group A) and multiple reoperations (Group B). RESULTS: Twenty-four patients (69%) belonged to group A and 11 (31%) to group B. The age < 65 years, male sex, incomplete resection at both initial surgery and first reoperation, and multicentric-diffuse pattern of regrowth at first recurrence are risk factors for multiple recurrences and reoperations. In group B, the WHO grade and Ki67-MIB1 increased in further recurrences in 54% and 64%, respectively. The time to recurrence was short in 7 cases (64%), whereas 4 patients (36%) further recurred after many years. Eight patients (73%) are still alive after 7 to 22 years and 2 to 4 reoperations. CONCLUSION: The extent of resection and the multicentric-diffuse pattern of regrowth at first recurrence are the main risk factors for multiple recurrences and reoperations. Repeated reoperations might be considered even in patients with extensive recurrent tumors before the anaplastic transformation occurs. In such cases, even partial tumor resections followed by radiation therapy may allow long survival in good clinical conditions.

Open-door extended endoscopic transorbital technique to the paramedian anterior and middle cranial fossae: technical notes, anatomomorphometric quantitative analysis, and illustrative case.

OBJECTIVE: The superior eyelid endoscopic transorbital approach (SETOA) provides a direct and short minimally invasive route to the anterior and middle skull base. Nevertheless, it uses a narrow corridor that limits its angles of attack. The aim of this study was to evaluate the feasibility and potential benefits of an "extended" conservative variant of the "standard" endoscopic transorbital approach-termed "open-door"-to enhance the exposure of lesions affecting the paramedian aspect of the anterior and middle cranial fossae. METHODS: First, the authors described the technical nuances of the open-door extended transorbital approach (ODETA). Next, they documented its morphometric advantages over standard SETOA. Finally, they provided a clinical-anatomical application to demonstrate enhanced exposure and better angles of attack to treat lesions occupying the paramedian anterior and middle cranial fossae. Five adult cadaveric specimens (10 sides) initially underwent standard SETOA and then extended open-door SETOA (ODETA to the paramedian anterior and middle fossae). The adjunct of hinge-orbitotomy, through three surgical steps and straddling the frontozygomatic suture, converted conventional SETOA to its extended open-door variant. CT scans were performed before dissection and uploaded to the neuronavigation system for quantitative analysis. The angles of attack on the axial plane that addressed four key landmarks, namely the tip of the anterior clinoid process (ACP), foramen rotundum (FR), foramen ovale (FO), and trigeminal impression (TI), were calculated for both operative techniques and compared. RESULTS: Hinge-orbitotomy of the extended open-door SETOA resulted in several surgical, functional, and esthetic advantages: it provided wider axial angles of attack for each of the target points, with a gain angle of 26.68° ± 1.31° for addressing the ACP (p < 0.001), 29.50° ± 2.46° for addressing the FR (p < 0.001), 19.86° ± 1.98° for addressing the FO (p < 0.001), and 17.44° ± 2.21° for addressing the lateral aspect of the TI (p < 0.001), while hiding the skin scar, avoiding temporalis muscle dissection, preserving flap vascularization, and decreasing the rate of bone infection and degree of orbital content retraction. CONCLUSIONS: The extended open-door technique may be specifically suited for selected patients affected by paramedian anterior and middle fossae lesions, with prevalent anteromedial extension toward the anterior clinoid, the foremost compartment of the cavernous sinus and FR and not completely controlled with the pure endoscopic transorbital approach.

The Course of the Trochlear Nerve Presented via a 3-Dimensional Photorealistic Anatomic Model.

OBJECTIVES: Several factors contribute to the anatomical complexity of the trochlear nerve, including small diameter, complex and longest intracranial course, deep location, and numerous neurovascular relationships. A 3-dimensional (3D) photorealistic model of the cranial nerves provides a detailed and immersive representation of the anatomy, enabling one to improve surgical planning, advanced surgical research, and training. The purpose of this work is to present a 3D photogrammetric study for a more intuitive and interactive way to explore and describe the entire course of trochlear nerve. METHODS: Two injected-fixed head human specimens (4 sides) were examined. The dissection protocol was divided into the following steps: 1) brain hemisphere exposure; 2) hemispherectomy dissecting all cranial nerves and partial removal of the free edge of the tentorium; 3) middle fossa and lateral wall of cavernous sinus exposure; and 4) orbital exposure. A detailed 3D photogrammetric model was generated for each dissection step. RESULTS: Four main volumetric models were generated during a step-by-step layered dissection of the entire nerve pathway highlighting its different segments. Finally, a full and integrated model of the entire course of the nerve was created. The models are available for visualization on monoscopic display, virtual, and augmented reality environment. CONCLUSIONS: The present photogrammetric model provides a more comprehensive understanding of the nerve's anatomy in its different segments, allows for customizable views thus simulating different perspectives, and can be a valuable alternative to traditional dissections. It is an advanced tool for surgical planning and surgical simulation as well as virtual reality representation of the anatomy.

Massive bilateral paraclinoidal subdural empyema and parenchymal temporopolar abscess with anatomical infection pathway in a chronic inhaling cocaine-addicted patient: A case report and literature review.

Background: Focal suppurative bacterial infections of the central nervous system (CNS), such as subdural empyemas and brain abscesses, can occur when bacteria enter the CNS through sinus fractures, head injuries, surgical treatment, or hematogenous spreading. Chronic cocaine inhalation abuse has been linked to intracranial focal suppurative bacterial infections, which can affect neural and meningeal structures. Case Description: We present the case of a patient who developed a cocaine-induced midline destructive lesion, a vast bilateral paraclinoidal subdural empyema, and intracerebral right temporopolar abscess due to cocaine inhalation abuse. The infection disseminated from the nasal and paranasal cavities to the intracranial compartment, highlighting a unique anatomical pathway. Conclusion: The treatment involved an endoscopic endonasal approach, followed by a right frontal-temporal approach to obtain tissue samples for bacterial analysis and surgical debridement of the suppurative process. Targeted antibiotic therapy helped restore the patient's neurological status.

The Sellar Region as Seen from Transcranial and Endonasal Perspectives: Exploring Bony Landmarks Through New Surface Photorealistic Three-Dimensional Model Reconstruction for Neurosurgical Anatomy Training.

BACKGROUND: Virtual reality-based learning of neuroanatomy is a new feasible method to explore, visualize, and dissect interactively complex anatomic regions. We provide a new interactive photorealistic three-dimensional (3D) model of sellar region microsurgical anatomy that allows side-by-side views of exocranial and endocranial surfaces to be explored, with the aim of assisting young neurosurgery residents in learning microsurgical anatomy of this complex region. METHODS: Four head specimens underwent an endoscopic endonasal approach extended to the anterior and posterior skull base to expose the main bony anatomic landmarks of the sellar region. The same bony structures were exposed from a transcranial perspective. By using a photogrammetry method, multiple photographs from both endocranial and exocranial perspectives, different for angulations and depth, were captured, fused, and processed through dedicated software. RESULTS: All relevant bony structures were clearly distinguishable in the 3D model reconstruction, which provides several benefits in neuroanatomy learning: first, it replicates bony structures with high degrees of realism, accuracy, and fidelity; in addition, it provides realistic spatial perception of the depth of the visualized structures and their anatomic relationships; again, the 3D model is interactive and allows a 360° self-guided tour of the reconstructed object, so that the learner can read the bones and their anatomic relationship from all desired points of view. CONCLUSIONS: Detailed knowledge of key surgical landmarks representing keyholes and/or anatomic structures to not violate is mandatory for safer surgery, especially for a complex region such as the skull base. Highly accurate virtual and functional neurosurgical models, such as photogrammetry, can generate a realistic appearance to further improve surgical simulators and learn neuroanatomy.

Time to Recurrence of Intracranial Meningiomas from a Monoinstitutional Surgical Series.

BACKGROUND: Meningiomas show variable tendency to recur. While risk factors of recurrence have been largely investigated in literature, a paucity of data is available on the time to recurrence. Our purpose was to identify main factors affecting the time to recurrence to assist preoperative treatment decision-making strategy and to define a tailored clinical and neuroradiological follow-up. METHODS: Data of 35 patients with intracranial meningioma recurrences have been retrospectively reviewed. Demographic (patient age at initial diagnosis and sex), radiologic (meningioma location, pattern of regrowth and topography of recurrences at first reoperation), pathologic (WHO grade and Ki67-MIB1 at initial surgery and at first reoperation, progesterone receptor [PR] expression), and surgical (extent of resection at initial surgery according to Simpsons grading system, number of reoperations) factors were analyzed. RESULTS: Time to recurrence ranged from 20 to 120 months. Extent of resection at initial surgery was Simpson grade I in 7 patients (20%), grade II in 10 (28.5%), grade III in 14 (40%), and grade IV in 4 (11.5%). Longer median time to recurrence was observed for skull base localization (P < 0.01), Simpson grades I and II versus grades III (P = 0.01) and IV (P = 0.02), values of Ki67-MIB1 ≤ 4% (P = 0.001), and PR > 60% (P = 0.03); conversely, sex, age, number of reoperations, unchanged/progression of Ki67, and/or World Health Organization grade between first surgery and reoperation did not correlate in statistically significant way with time to recurrence. CONCLUSIONS: The extent of resection and the Ki67-MIB1 represent the most important factors predicting shorter recurrence time of intracranial meningiomas. Patients with incomplete (Simpson grades III and IV) resection and high Ki67-MIB1 values, especially at non-skull base localization and with low PR values, require a closer short-term clinical and radiologic follow-up in the first years after surgery.

The Goutallier Classification System: How does Paravertebral Adipose Degeneration Change in Patients with Symptomatic Lumbar Spinal Stenosis?

STUDY DESIGN: Retrospective, observational study. OBJECTIVE: To determine the relationship between the Goutallier Classification System (GS) and anthropometric, clinical, and radiological features in 168 patients with lumbar spinal stenosis (LSS). BACKGROUND: There is no agreement on a classification system that is both reliable and easy to use for describing the severity of fatty degeneration in the paravertebral muscles of the lower back in patients with symptomatic lumbar spinal stenosis. This study aimed to determine the statistical relationship between the GS and anthropometric, clinical, and radiological factors in 168 patients with LSS. METHODS: This study was conducted on 168 patients with LSS scheduled for elective decompressive surgery. A control group of 110 healthy individuals was enrolled. The study assessed paralumbar musculature fatty infiltration using GS on preoperative Magnetic Resonance Imagin (MRI). We evaluated the statistical association between patient age, Body Mass Index (BMI), preoperative Oswestry Disability Index (ODI) questionnaire, and cross-sectional areas (CSAs) of the dural sac and lumbar paraspinal muscles. Multivariate analysis was performed to adjust for confounding. RESULTS: This study enrolled 168 patients with symptomatic LSS (95 men, 73 women; mean±standard deviation; range); age: 67,81±9,38; (32,78 - 92,34) years; BMI: 28,29±3,36; (19,95 - 38,10) kg/m2. The control group was comprised of 110 healthy patients (61 men and 49 women). Age, sex, BMI, and ES-CSA were not significantly different between the two groups. We found a direct relationship between GS grade and age, and an inverse relationship between GS grade and DS-, LM-, ES-, and PM-CSAs. (Table 2 and Fig. 5). Univariate analyses showed the variables statistically related to a higher GS grade included patient age, (P<0.001), ODI (P=0.136), DS-CSA (P=0.011), LM-CSA (P< 0.001), ES-CSA (P<0.001), and PM-CSA (P<0.001). Multivariate least squares analysis showed the GS grade to be influenced by patient age (P=0.01), LM-CSA (P=0.002), ES-CSA (P=0.002), and PM-CSA (P=0.003). CONCLUSIONS: GS shows great potential as a tool for evaluating fat infiltration in the paralumbar muscles. This measure does not correlate with the ODI and BMI, but is related to all radiological parameters and patient age. Further prospective studies are required to establish a link between preoperative and postoperative outcomes in the setting of paraspinal fat infiltration.

Multimodal Use of Contact Endoscopy in Neurosurgery: Case Series with Technical Note and Literature Review.

BACKGROUND: Originally adopted for the cytological screening of cervical and uterine cancer, contact endoscopy (CE) is now widely used in several fields of oncological surgery. The CE method, with magnification power up to 150x, was designed to enhance visualization and identify microscopic changes indicative of precancerous and cancerous lesions at early stages. In this pilot study, we evaluated the multimodal applications of CE during different endoscopic intracranial neurosurgical procedures. METHODS: Twenty patients with skull base lesions underwent surgery using different minimally invasive endoscopic approaches (endonasal, transorbital, and supraorbital). CE was used to distinguish the pathology from the surrounding healthy tissue by positioning the endoscope either in proximity or directly onto the target tissue. Special attention was given to the visualization of the margins of the lesion to differentiate compression/displacement from infiltration of the normal surrounding tissue. RESULTS: With its unprecedented range of magnification, CE could clearly identify the microvascular pattern and cytological architecture of a tissue not detectable by simple white light endoscopy, with no reported damage due to heat transmission or iatrogenic injuries. All the lesions diagnosed as "presumed neoplastic tissue" by CE were confirmed by histopathology. The most promising results were observed in surgeries for meningioma and pituitary adenoma, as these lesions exhibit distinctive microvascular networks. CONCLUSIONS: CE represents a new and effective technique for the in vivo identification of pathological microvascular and tissue features, allowing preservation of normal tissue during different endoscopic approaches. The use of CE could improve diagnostic accuracy and assist in intraoperative decision-making, becoming a key tool in various applications in neurosurgical field.

Sporadic Spinal Hamartoma in Adults: A Rare Pathologic Entity.

BACKGROUND: Sporadic spinal hamartomas in adults are extremely rare tumor-like lesions, without defined guidelines of treatment. The aim of this study is to investigate the peculiar features of this pathologic entity to support a more accurate diagnosis and management. METHODS: A comprehensive and detailed literature review of sporadic spinal hamartomas in adults, including a personal case, was performed. Demographic (sex and age), clinical (presenting symptoms), radiologic and pathologic (size, localization, dural and spinal cord relationship of lesion) features, as well as treatment (time to surgery, extent of resection, perioperative and postoperative complications) and outcome (clinical) data were analyzed. RESULTS: Seven studies, including 7 patients, were eligible for the review. A personal case was also added. Sporadic adult spinal hamartomas equally affect males and females, in a range of age from 18 to 75 years; sensory radicular deficits were detected in all patients at clinical onset; thoracic segment (4/8) of the spine and intradural compartment (6/8) were most involved. All patients underwent surgery and just one experimented postoperative complication; gross total resection was achieved in only 3 patients, mainly in an extradural localization; clinical improvement at last follow-up was reported in all but 1 patient. CONCLUSIONS: Spinal hamartomas in adults may sometimes account for progressive worsening of neurologic symptoms and lead to potentially irreversible neurologic deficit; therefore, prompt and adequate diagnosis and treatment are mandatory. Surgical resection represents the only curative treatment and is indicated for symptomatic lesions to achieve neurologic symptoms restoration or arrest/prevent their progressive deterioration.

Impact of deep brain stimulation therapy on the vertebral sagittal balance in Parkinson's disease patients.

Parkinson's disease (PD) is characterized by cardinal motor signs: 4-6 Hz resting tremor, rigidity, and bradykinesia. In addition, 3-18% of PD patients have camptocormia, an abnormal forward flexion of the thoracolumbar spine, which may have a negative impact on patients' quality of life. Different possible treatments have been suggested for such a condition, but no one is resolutive. This study aims to define the possible impact of DBS, with selective targeting on the dorsal-lateral region of the STN, on the sagittal balance of patients affected by PD. Among all patients that have undergone DBS procedures in our institution, we selected eight subjects, four females and four males, with selective targeting on the dorsal-lateral region of the subthalamic nucleus (STN) because of camptocormia and other severe postural changes. Radiological assessments of spinal balance parameters before surgery and at 6 and 12 months postoperatively were carried out. Comparison of preoperative and postoperative spine X-ray data showed a statistically significant improvement in dorsal kyphosis angle (D-Cobb) 12 months after the operation. Deep brain stimulation with selective targeting of the dorsal lateral part of the STN may induce changes of the posture in patients with Parkinson's disease 12 months after the operation, which appears to improve in this small sample size, but larger observational and controlled trials would be required to confirm this observation.

The Transorbital Approach, A Game-Changer in Neurosurgery: A Guide to Safe and Reliable Surgery Based on Anatomical Principles.

During the last few years, the superior eyelid endoscopic transorbital approach has been proposed as a new minimally invasive pathway to access skull base lesions, mostly in ophthalmologic, otolaryngologic, and maxillofacial surgeries. However, most neurosurgeons performing minimally invasive endoscopic neurosurgery do not usually employ the orbit as a surgical corridor. The authors undertook this technical and anatomical study to contribute a neurosurgical perspective, exploring the different possibilities of this novel route. Ten dissections were performed on ten formalin-fixed specimens to further refine the transorbital technique. As part of the study, the authors also report an illustrative transorbital surgery case to further detail key surgical landmarks. Herein, we would like to discuss equipment, key anatomical landmarks, and surgical skills and stress the steps and details to ensure a safe and successful procedure. We believe it could be critical to promote and encourage the neurosurgical community to overcome difficulties and ensure a successful surgery by following these key recommendations.

Atypical Teratoid/Rhabdoid Tumor of the Nervous System in Adults: Location-Related Features and Outcome.

BACKGROUND: Atypical teratoid/rhabdoid tumor (AT/RT) of the nervous system is a rare and highly malignant neoplasm, mainly affecting children, first recognized as a pathologic entity in 1996 and added to the World Health Organization Classification of the Tumors of the Central Nervous System in 2000. AT/RT is even rarer among adults and is associated with a worse prognosis. The aim of the present study was to analyze the different tumor features according to the location in adults. METHODS: A comprehensive and detailed literature review of AT/RTs in adults was made. The demographic, management, and outcome data associated with tumor location were analyzed and compared; histopathologic and molecular features were also discussed. Furthermore, we added our personal case with brain hemispheric localization and reported a progression-free survival of 103 months after gross total resection and adjuvant radiotherapy showing a peculiar histopathologic pattern. RESULTS: Female sex is mainly affected by AT/RT on median localizations, both intracranial and spinal, and by all sellar region cases. Gross total resection is mainly achieved among lateral compared with median localizations. Combined radiotherapy and chemotherapy is the most adopted adjuvant treatment in all tumor localizations and is related to better outcome. Postoperative death is reported only among sellar region localizations, whereas brain hemispheric cases show the best overall survival. CONCLUSIONS: AT/RTs show different and peculiar features according to their location, which significantly affects the outcome; precise knowledge of them helps the neurosurgeon in planning the best strategy for treatment.

A New Perspective on the Cavernous Sinus as Seen through Multiple Surgical Corridors: Anatomical Study Comparing the Transorbital, Endonasal, and Transcranial Routes and the Relative Coterminous Spatial Regions.

Background: The cavernous sinus (CS) is a highly vulnerable anatomical space, mainly due to the neurovascular structures that it contains; therefore, a detailed knowledge of its anatomy is mandatory for surgical unlocking. In this study, we compared the anatomy of this region from different endoscopic and microsurgical operative corridors, further focusing on the corresponding anatomic landmarks encountered along these routes. Furthermore, we tried to define the safe entry zones to this venous space from these three different operative corridors, and to provide indications regarding the optimal approach according to the lesion's location. Methods: Five embalmed and injected adult cadaveric specimens (10 sides) separately underwent dissection and exposure of the CS via superior eyelid endoscopic transorbital (SETOA), extended endoscopic endonasal transsphenoidal-transethmoidal (EEEA), and microsurgical transcranial fronto-temporo-orbito-zygomatic (FTOZ) approaches. The anatomical landmarks and the content of this venous space were described and compared from these surgical perspectives. Results: The oculomotor triangle can be clearly exposed only by the FTOZ approach. Unlike EEEA, for the exposure of the clinoid triangle content, the anterior clinoid process removal is required for FTOZ and SETOA. The supra- and infratrochlear as well as the anteromedial and anterolateral triangles can be exposed by all three corridors. The most recently introduced SETOA allowed for the exposure of the entire lateral wall of the CS without entering its neurovascular structures and part of the posterior wall; furthermore, thanks to its anteroposterior trajectory, it allowed for the disclosure of the posterior ascending segment of the cavernous ICA with the related sympathetic plexus through the Mullan's triangle, in a minimally invasive fashion. Through the anterolateral triangle, the transorbital corridor allowed us to expose the lateral 180 degrees of the Vidian nerve and artery in the homonymous canal, the anterolateral aspect of the lacerum segment of the ICA at the transition zone from the petrous horizontal to the ascending posterior cavernous segment, surrounded by the carotid sympathetic plexus, and the medial Meckel's cave. Conclusions: Different regions of the cavernous sinus are better exposed by different surgical corridors. The relationship of the tumor with cranial nerves in the lateral wall guides the selection of the approach to cavernous sinus lesions. The transorbital endoscopic approach can be considered to be a safe and minimally invasive complementary surgical corridor to the well-established transcranial and endoscopic endonasal routes for the exposure of selected lesions of the cavernous sinus. Nevertheless, peer knowledge of the anatomy and a surgical learning curve are required.

3-Dimensionally Printed Affordable Nose Model: A Reliable Start in Endoscopic Training for Young Neurosurgeons.

BACKGROUND: Training neurosurgical skills is one of the most important tasks of a residency program. Techniques' complexity and pathology rarity define a long learning curve for mastering different surgical skills for which simulation on anatomic samples is extremely important. For this purpose, cadaver laboratory training is the most reliable tool. However, since access to cadaveric specimens is limited, due to costs and availability, surgical skills could be developed using inanimate models. This work aimed to develop a printable 3-dimensional model of the nasal cavity and sellar floor using an open-source downloadable file, to give residents the opportunity to improve their endoscopic surgical skills in a low-risk atmosphere with little cost. METHODS: The 3D model was realized taking as a sample a real-case CT scan imaging from which the sellar floor was removed. A quail egg was placed underneath the printed model covering the sellar floor opening. Under endoscopic visualization, the "sellar floor" was drilled by each participant with the goal of sparing the egg's inner membrane. Once the task was achieved, surgeons were asked to participate in a satisfaction survey. RESULTS: The total cost for printing was 6.31€ (6,72$). A satisfaction survey showed technical improvement (90%), increased confidence (80%), and bringing learned skills into the operating room (70%), leading to a 100% agreement in introducing this project into residency programs. CONCLUSIONS: Training on affordable anatomic models represents a useful tool in technical skills improvement. We believe this model could help residents bring their technical capabilities to more sophisticated levels.

The anterolateral triangle as window on the foramen lacerum from transorbital corridor: anatomical study and technical nuances.

OBJECTIVE: Neurosurgical indications for the superior eyelid transorbital endoscopic approach (SETOA) are rapidly expanding over the last years. Nevertheless, as any new technique, a detailed knowledge of the anatomy of the surgical target area, the operative corridor, and the specific surgical landmark from this different perspective is required for a safest and successful surgery. Therefore, the aim of this study is to provide, through anatomical dissections, a detailed investigation of the surgical anatomy revealed by SETOA via anterolateral triangle of the middle cranial fossa. We also sought to define the relevant surgical landmarks of this operative corridor. METHODS: Eight embalmed and injected adult cadaveric specimens (16 sides) underwent dissection and exposure of the cavernous sinus and middle cranial fossa via superior eyelid endoscopic transorbital approach. The anterolateral triangle was opened and its content exposed. An extended endoscopic endonasal trans-clival approach (EEEA) with exposure of the cavernous sinus content and skeletonization of the paraclival and parasellar segments of the internal carotid artery (ICA) was also performed, and the anterolateral triangle was exposed. Measurements of the surface area of this triangle from both surgical corridors were calculated in three head specimens using coordinates of its borders under image-guide navigation. RESULTS: The drilling of the anterolateral triangle via SETOA unfolds a space that can be divided by the course of the vidian nerve into two windows, a wider "supravidian" and a narrower "infravidian," which reveal different anatomical corridors: a "medial supravidian" and a "lateral supravidian," divided by the lacerum segment of the ICA, leading to the lower clivus, and to the medial aspect of the Meckel's cave and terminal part of the horizontal petrous ICA, respectively. The infravidian corridor leads medially into the sphenoid sinus. The arithmetic means of the accessible surface area of the anterolateral triangle were 45.48 ± 3.31 and 42.32 ± 2.17 mm2 through transorbital approach and endonasal approach, respectively. CONCLUSION: SETOA can be considered a minimally invasive route complementary to the extended endoscopic endonasal approach to the anteromedial aspect of the Meckel's cave and the foramen lacerum. The lateral loop of the trigeminal nerve represents a reliable surgical landmark to localize the lacerum segment of the ICA from this corridor. Nevertheless, as any new technique, a learning curve is needed, and the clinical feasibility should be proven.

A "masked" pleomorphic xanthoastrocytoma.

The latest WHO Classification of tumours of the Central Nervous System (CNS) emphasizes the necessity of an integrated diagnostic approach during the workup of a CNS neoplasm. In addition to the mutational status, assessment of methylation profile of a tumour emerged as a helpful (often necessary) tool to make a correct and unequivocal diagnosis. Here we present a case of a Pleomorphic Xanthoastrocytoma with clinical, radiological and histopathological findings remarkably overlapping with a recently described paediatric-type glioma namly Polymorphic Low-grade Neuroepithelial Tumour of the Young (PLNTY). The differential diagnosis here discussed represents a methodological paradigm in the modern neuropathology. In fact, the presentation of this case is a demonstration that in day-to-day practice, clinical, radiological, and histopathological data can all be misleading, and the correct diagnosis can only be reached by integration with molecular analysis. In the modern neuro-oncology, it is by far mandatory for all the specialists dealing with cerebral tumours to "contaminate" their own cultural heritage with other ones, to optimally manage a patient with CNS tumour.

Meningiomas of the rolandic region: risk factors for motor deficit and role of intra-operative monitoring.

OBJECTIVE: Meningiomas of the rolandic region are associated to high risk of postoperative motor deficits. This study discusses the factors affecting motor outcome and recurrences from the analysis of a monoinstitutional case series and eight studies from a literature review. METHODS: Data of 75 patients who underwent surgery for meningioma of the rolandic region were retrospectively reviewed. The analyzed factors included tumor location and size, clinical presentation, magnetic resonance imaging (MRI) and surgical findings, brain-tumor interface, extent of resection, postoperative outcome and recurrence. Eight studies from literature on rolandic meningiomas treated with or without intraoperative monitoring (IOM) were reviewed with the aim to define the impact of IOM on the extent of resection and motor outcome. RESULTS: Among the 75 patients of the personal series, the meningioma was on the brain convexity in 34 (46%), at the parasagittal region in 28 (37%) and at the falx in 13 (17%). The brain-tumor interface was preserved in 53 cases (71%) at MRI and in 56 (75%) at surgical exploration. Simpson grade I resection was obtained in 43% of patients, grade II in 33%, grade III in 15% and grade IV in 9%. The motor function worsened postoperatively in 9 among 32 cases with preoperative deficit (28%) and in 5 among 43 with no preoperative deficit (11.5%); definitive motor deficit was evidenced in overall series at follow-up in 7 (9.3%). Patients with meningioma with lost arachnoid interface had significant higher rates of worsened postoperative motor deficit (p = 0.01) and seizures (p = 0.033). Recurrence occurred in 8 patients (11%). The analysis of the 8 reviewed studies (4 with and 4 without IOM) shows in the group without IOM higher rates of Simpson grades I and II resection (p = 0.02) and lower rates of grades IV resection (p = 0.002); no significant differences in postoperative immediate and long-term motor deficits were evidenced between the two groups. CONCLUSIONS: Data from literature review show that the use of IOM does not affect the postoperative motor deficit Therefore, its role in rolandic meningiomas resection remains to be determined and will be defined in further studies.