Skull Base Region Research Articles

Morphometric analysis of the skull base and palatal regions for gender identification using CBCT: a retrospective study.

The objectives of this study were to evaluate the accuracy of morphometry of skull base and palate in gender discrimination using cone beam computed tomography (CBCT) scanning and to assess the accuracy of the results among a sample of the Arab population. Using CBCT scans, a cross-sectional analysis was conducted on 142 consented patients who underwent various dental procedures at the University Dental Hospital, Sharjah (UDHS). Of these patients, 70 were females and 72 were males, with respective means of 38.5 and 36.2 years. Eleven parameters related to skull base and palatal region were measured on the CBCT scans by two expert radiologists followed by statistical analysis. There was significant gender-based difference in the mean palatal width (PW) (p=0.001), mean palatal height (PH) (p=0.005). Among other skull base region parameters that were significant in term of gender-based difference like; the clivus length (CL) (p<0.001), occipital condyle height (OCH) (p<0.001), basal angle (BA) (p=0.006) and transverse diameter of foramen magnum (p=0.003). Only palate variables showed a significant age difference. Discriminant analysis related to gender showed that occipital condyle height was the most accurate and best discriminator among the skull base region parameters. The use of discriminant analysis in CBCT based on skull base and palatal region variables provides an efficient method for determining gender, which is particularly valuable in forensic science and anthropological research. Accurate gender identification is crucial in forensic investigations, and the skull base region, being a stable and sexually dimorphic anatomical feature, can serve as a reliable marker for this purpose.

Muscle metastasis from cervical chordoma: a case report.

Chordomas are rare primary bone tumours that commonly occur in the sacrococcygeal and skull base region and have high rates of local recurrence. They have a locally aggressive course and the most common site of distant metastasis is the lung. The aim of this case report is to present the imaging findings of instance of muscle metastasis, a rare occurrence in cervical chordoma.

The Incidence of Radiologic Evidence of Sinusitis Following Endoscopic Pituitary Surgery: A Multi-Center Study.

Background: Endoscopic endonasal skull base surgery has become a viable alternative to open procedures for the surgical treatment of benign and malignant lesions in the sinonasal and skull base regions. As in sinus surgery, skull base surgery may cause crusting and posterior rhinorrhea, particularly when a nasoseptal flap is required for skull base reconstruction. Post-operative radiological sinonasal findings have been reported previously with no clear correlation with intraoperative decision-making. As in open surgery, endoscopic surgery is not standardized and there is variability in the intervention to assist with exposure and skull base repair. These modifications, including middle turbinate resection, nasoseptal flap, fat graft, and maxillary antrostomy have the potential for nasal morbidity. The aim of this study was to evaluate whether specific interventions during surgery or specific patient and tumor characteristics harbor a more significant risk of causing nasal morbidity post-operatively, as demonstrated by post-operative imaging. Methods: A retrospective analysis of all patients who underwent endoscopic endonasal skull base surgery for pituitary lesions at two major referral centers was performed. Data on demographic, clinical, and pathological features were collected, and pre- and post-operative imaging studies (computed tomography (CT) and magnetic resonance imaging (MRI)) were reviewed and scored according to the Lund-Mackay (LM) scoring system. Results: The study included 183 patients. Radiographic evidence of sinusitis was observed in 30 patients (LM score > 4) in post-operative imaging studies. Patients who underwent middle turbinectomy or nasoseptal flap were found to have significantly higher LM scores on follow-up imaging. A nasoseptal flap was found to be associated with an average increase in LM score of 1.67 points and middle turbinectomy with an average increase of 2.21 points. There was no correlation between tumor size and findings that were compatible with sinusitis on post-operative imaging. Conclusions: The findings of the present study suggest that endoscopic endonasal skull base surgery is associated with radiological evidence of sinusitis. Nasoseptal flap reconstruction and middle turbinectomy were strongly associated with radiographic sinusitis and should be judiciously performed during surgery. A clinical correlation is needed for further recommendations.

Head injury mechanisms of the occupant under high-speed train rear-end collision

To improve the passive safety of high-speed trains, it is very important to understand the mechanism of head injury in high-speed train collisions. In this study, the head injury mechanisms of occupants in high-speed train rear-end collisions were investigated based on the occupant-seat coupling model, which included a dummy representing the Chinese 50th percentile adult male. The typical injury responses in terms of skull fractures, brain contusions, and diffuse axonal injury (DAI) were analyzed. Meanwhile, the influences of collision speed and seat parameters on head injury response were examined. The simulation results indicate that the skull fractures primarily occur at the skull base region due to excessive neck extension, while the brain contusions and DAI result from the relative displacement of different brain regions. The increase in collision speed will promote the probability of skull fracture, brain contusion, and DAI. Seat design modifications, such as reduced seat spacing, increased seat backrest angles, and selecting the appropriate cushion angle (76°) and friction coefficient (0.15), can effectively mitigate probably occupant's head injury.

Endoscopic Endonasal Reconstruction of Intraoperative Cerebrospinal Fluid Leak in Different Skull Base Regions: Outcomes, Meningitis, and Risk Factors

ObjectiveVarious non-vascularized or vascularized techniques have been adopted in endoscopic endonasal surgery (EES) for repairing intraoperative cerebrospinal fluid (CSF) leaks after tumor resection. Vascularized nasoseptal flaps (VNSF), free nasoseptal grafts (FNSG), free turbinate grafts (FTG), fascia lata and mashed muscle (FLMM) are frequently used. Outcomes of those grafts applied in the defects of different regions need to be clarified. MethodsThe data from a series of 162 patients with skull base tumor who underwent EES that had intraoperative CSF leak between Jan 2012 and Jan 2021 were retrospectively analyzed. The regions included anterior skull base (ASB), sellar region, clivus and infratemporal fossa (ITF). Repair failure rate (RFR), meningitis rate and associated risk factors were assessed. ResultsIn total, 172 reconstructions were performed in 162 patients for the four sites of the skull base. There were 7 cases (4.3%) that had postoperative CSF leaks, which required second repair. The RFR for ASB, sellar region, clivus, and ITF was 2.6%, 2.2%, 16.7%, and 0%, respectively. The clivus defect was an independent risk factor for repair failure (P<0.01). The postoperative meningitis rate was 5.6%. Repair failure was an independent risk factor for meningitis (P < 0.01). ConclusionsVNSF, FNSG, FTG, FLMM are reliable autologous materials for repairing the dural defects in different regions during EES. Clivus reconstruction remains a great challenge, which had a higher RFR and meningitis rate. Repair failure is significantly associated with postoperative meningitis.

The cavernous sinus: An anatomic study with clinical implication.

The management of lesions involving the cavernous sinus remains a formidable challenge. To optimize care for patients with tumors extending into this skull base region a detailed understanding of the surrounding osteology as well as neural and vascular relationships is requisite. This thesis examines the gross anatomy of the region and highlights important surgical implications drawn from these as well as previously published studies. A review of the historical scientific, anatomic, clinical, and surgical literature extending to the present (1992) relating to the cavernous sinus has been performed and discussed. Additionally, the author has performed and described cadaveric dissections revealing novel details about the macroscopic (dural and neurovascular anatomic relationships) and microscopic structure of the cavernous sinus. A series of cases of cavernous sinus pathologies that were addressed in an interdisciplinary surgical approach at the author's institution is also reported. Included in this report is a comprehensive review of the embryology of the cavernous sinus and its associated neurovascular structures. Cadaveric dissections have also revealed novel details about dural/meningeal compartments of the cavernous sinus as well as well as associated arterial, venous, and neural relationships. Microscopic observations also reveal novel fundamental insights into the components and structure of the cavernous sinus. Clinical examples from 20 patients illustrate the critical importance for clinical application of cavernous sinus anatomic knowledge to the surgical treatment of pathologies in this region. The cavernous sinus is a tripartite venous osteomeningeal compartment intimately neighboring vital structures including the optic tracts, pituitary gland, cranial nerves III, IV, V, V, VI, and the internal carotid artery. Surgical management of cavernous sinus lesions has and continues to evolve with increasing anatomic and clinical study as well as advancements in diagnostic and surgical methodologies. NA.

Artifact Assessment in the Skull Base Region of Head CT Images with Various Tilt Angles Relative to the Orbitomeatal Line

The aim of this study was to evaluate artifacts in the skull base region of head computed tomography (CT) images with various tilt angles relative to the orbitomeatal line. CT images of a head phantom acquired by helical and non-helical scanning with the tilt angles set from 0 to 20 degrees in 5-degree increments were evaluated in this study. Regions of interest (ROIs) were set at the cerebellum, temporal lobe, frontal lobe, and basal ganglia in the phantom images. Artifacts were evaluated by the coefficient of variation (CV) of the mean CT value between ROIs and the location parameter (β) of the Gumbel method. The CV and β values increased with increasing tilt angle for both helical and nonhelical images in the frontal lobes, but both decreased in the cerebellar region. In the temporal lobe and basal ganglia, there was no trend of change with tilt angle. Increasing the tilt angle relative to the OM line increased artifacts at the frontal lobes and decreased artifacts at the cerebellar region.

The Role of Augmented Reality Neuronavigation in Transsphenoidal Surgery: A Systematic Review.

In the field of minimally invasive neurosurgery, microscopic transsphenoidal surgery (MTS) and endoscopic transsphenoidal surgery (ETS) have been widely accepted as a safe approach for pituitary lesions and, more recently, their indications have been extended to lesions at various skull base regions. It is mandatory during transsphenoidal surgery (TS) to identify key anatomical landmarks in the sphenoid sinus and distinguish them from the lesion. Over the years, many intraoperative tools have been introduced to improve the neuronavigation systems aiming to achieve safer and more accurate neurosurgical interventions. However, traditional neuronavigation systems may lose the accuracy of real-time location due to the discrepancy between the actual surgical field and the preoperative 2D images. To deal with this, augmented reality (AR)-a new sophisticated 3D technology that superimposes computer-generated virtual objects onto the user's view of the real world-has been considered a promising tool. Particularly, in the field of TS, AR can minimize the anatomic challenges of traditional endoscopic or microscopic surgery, aiding in surgical training, preoperative planning and intra-operative orientation. The aim of this systematic review is to analyze the potential future role of augmented reality, both in endoscopic and microscopic transsphenoidal surgeries.

Conventional Magnetic Resonance Imaging (MRI) and histopathology agreement for the diagnosis of intracranial meningioma at Dr. Soetomo General Hospital, Surabaya, January 2016–December 2021: a single center study

Link of Video Abstract: https://youtu.be/OG7qXwNHzHQ Background: Meningioma, a prevalent intracranial neoplasm, ranks among the most frequently encountered tumors within the cranial cavity. The utilization of Magnetic Resonance Imaging (MRI) in the diagnostic process of meningioma has proven to be highly valuable. This study aims to evaluate the Conventional-MRI and histopathology agreement for the diagnosis of intracranial meningioma at Dr. Soetomo General Hospital, Surabaya. Methods: This study presents a diagnostic test and retrospective case-control analysis to evaluate the precision of head MRI in diagnosing intracranial meningioma, as confirmed by histopathological examination. The research was conducted at Dr. Soetomo Surabaya General Hospital from January 2016 to December 2021. Sample size calculations were performed on a cohort of patients diagnosed with intracranial meningioma who underwent head magnetic resonance imaging (MRI) scans and histopathological examinations at the Radiology and Anatomical Pathology Installation of Dr. Soetomo General Hospital. Only patients who satisfied the predetermined inclusion and exclusion criteria were included in the study. Data were analyzed using SPSS version 25.0 for Windows. Results: At the time of diagnosis, it was observed that the average diameter of grade II/III meningioma was 6.6 ± 1.5 cm, which was found to be greater than the average diameter of grade I meningioma, measuring 4 ± 1.92 cm. The prevalence of grade I meningioma was higher in the skull base region higher in the skull base region, accounting for approximately 36% of cases. Conversely, grade II/III meningioma was found more frequently in the non-skull base area, constituting approximately 76% of cases. In our investigation, it was observed that there exists a higher occurrence of irregular border shape in grade II/III meningioma, accounting for approximately 75% of cases, as compared to grade I meningioma, which only accounts for 14.2% of cases. The presence of contrast enhancement in meningiomas can provide valuable insights into their histological grade. Grade II/III meningiomas exhibit a higher degree of contrast enhancement, which is observed to be heterogeneously distributed in approximately 75% of cases. Conclusion: This study highlights the potential of MRI as a valuable tool in assessing the grade of meningioma while emphasizing the importance of considering other diagnostic modalities and clinical factors to ensure accurate diagnosis and treatment decisions.

Anatomical variation in the sphenoidal sinuses in patients with chronic rhinosinusitis: A CT scan study

Computerized tomography (CT) of the skull base region has become an indispensable tool for endoscopic sinonasal surgery. ObjectivesFundamental knowledge of the sinus anatomy is crucial for preoperative surgical planning. The aim of this research was to evaluate associations between the anatomical variations sphenoidal sinuses and chronic rhinosinusitis (CRS) by using CT. MethodsA descriptive study was performed on patients with CRS, who were referred to the department of radiodiagnosis and imaging for CT scanning. Parameters were compared between the study and control groups. ResultsAmong the anatomical variations, the presence of bilateral accessory septa within the sphenoidal sinus, and dehiscence and protrusion of the internal carotid artery and optic nerve (ON), were high in men and women in the case group compared with the control group. Among the anatomical variations in the sinonasal region of the male participants, a significant association (p < 0.05) was observed with ON protrusion and ON dehiscence. ON protrusion (OR = 2.168) in men was associated with elevated risk of CRS in the study population. ConclusionKnowledge of the anatomical variations in the sphenoid sinuses enables better understanding of the limits of surgical dissection during the treatment of sphenoid sinus surgeries.

Diffusion MRI of the facial-vestibulocochlear nerve complex: a prospective clinical validation study

ObjectivesSurgical planning of vestibular schwannoma surgery would benefit greatly from a robust method of delineating the facial-vestibulocochlear nerve complex with respect to the tumour. This study aimed to optimise a multi-shell readout-segmented diffusion-weighted imaging (rs-DWI) protocol and develop a novel post-processing pipeline to delineate the facial-vestibulocochlear complex within the skull base region, evaluating its accuracy intraoperatively using neuronavigation and tracked electrophysiological recordings.MethodsIn a prospective study of five healthy volunteers and five patients who underwent vestibular schwannoma surgery, rs-DWI was performed and colour tissue maps (CTM) and probabilistic tractography of the cranial nerves were generated. In patients, the average symmetric surface distance (ASSD) and 95% Hausdorff distance (HD-95) were calculated with reference to the neuroradiologist-approved facial nerve segmentation. The accuracy of patient results was assessed intraoperatively using neuronavigation and tracked electrophysiological recordings.ResultsUsing CTM alone, the facial-vestibulocochlear complex of healthy volunteer subjects was visualised on 9/10 sides. CTM were generated in all 5 patients with vestibular schwannoma enabling the facial nerve to be accurately identified preoperatively. The mean ASSD between the annotators’ two segmentations was 1.11 mm (SD 0.40) and the mean HD-95 was 4.62 mm (SD 1.78). The median distance from the nerve segmentation to a positive stimulation point was 1.21 mm (IQR 0.81–3.27 mm) and 2.03 mm (IQR 0.99–3.84 mm) for the two annotators, respectively.Conclusionsrs-DWI may be used to acquire dMRI data of the cranial nerves within the posterior fossa.Clinical relevance statementReadout-segmented diffusion-weighted imaging and colour tissue mapping provide 1–2 mm spatially accurate imaging of the facial-vestibulocochlear nerve complex, enabling accurate preoperative localisation of the facial nerve. This study evaluated the technique in 5 healthy volunteers and 5 patients with vestibular schwannoma.Key Points• Readout-segmented diffusion-weighted imaging (rs-DWI) with colour tissue mapping (CTM) visualised the facial-vestibulocochlear nerve complex on 9/10 sides in 5 healthy volunteer subjects.• Using rs-DWI and CTM, the facial nerve was visualised in all 5 patients with vestibular schwannoma and within 1.21–2.03 mm of the nerve’s true intraoperative location.• Reproducible results were obtained on different scanners.

Very delayed CSF leak in patients after craniotomy for resection of skull base tumors

ObjectiveCerebrospinal fluid (CSF) leak is a potentially dangerous neurosurgical complication. Delayed CSF leak has already been described after trauma, radiation therapy and endonasal transsphenoidal surgery for Sella turcica pathologies. Still, very few reported cases describe delayed CSF leak after craniotomy for tumors. We present our experience with patients showing delayed CSF leak after skull base tumor resection. MethodsData for all tumors resected from the skull base region from January 2004 to December 2018 was retrieved from the surgeon’s prospective database and supplemented with a retrospective file review. Patients who presented CSF leak within the first 12 months after surgery and those with a history of trauma or radiation-based treatment to the skull base region were excluded from the study. Epidemiology, clinical presentation, previous surgical approach, pathology, interval between craniotomy and CSF leak and proposed treatment were analyzed. ResultsOverall, more than two thousand patients underwent surgery for resection of skull base tumors during the study period. Six patients (two male, four female; mean age 57.5 years, range 30–80) presented with delayed CSF leak, including five (83%) who presented with bacterial meningitis. After skull base tumor resection, CSF leak developed in a mean of 72 months (range 12–132). Three patients underwent retrosigmoid craniotomy, two for resection of cerebellopontine angle epidermoid cyst and one for resection of a petro tentorial meningioma; one had trans petrosal retrolabyrinthine craniotomy for resection of a petroclival epidermoid cyst; one had far lateral craniotomy for resection of a foramen magnum meningioma; and one had pterional craniotomy for resection of a cavernous sinus meningioma. All patients underwent surgical re-exploration and repair. CSF leak was managed with mastoid obliteration in five patients and skull base reconstruction with fat graft in one. ConclusionRecognition of very delayed CSF leak as a potential complication after resection of skull base tumors may be useful tool in long-term patient management. In our experience, these patients usually present with bacterial meningitis. Surgical options should be considered as a definitive treatment.

Fascial layers encountered in the lateral skull base region: A cadaveric and radiological analysis.

In our experience, the anterior carotid sheath forms an important plane of dissection when excising temporal bone region cancers. However, its anatomical composition, relationships, and radiological appearance remains unclear. Eight sides of cadaveric heads were dissected. Anatomical findings were correlated with a high-resolution baseline T1 MRI. The anterior carotid sheath was formed by the tensor-vascular-styloid fascia, stylopharyngeal fascia, buccopharyngeal fascia (BPF), and longus capitis fascia (LCF), and appeared as a hypointense line on MRI. Not previously described, the glossopharyngeal nerve pierced the sheath 9.0 mm (SD 2.1 mm) below the skull base and traveled through its LCF and BPF layers to exit near the pharynx. Multiple fascial layers formed the anterior carotid sheath at the skull base, and this was radiologically identifiable. Further studies are required to validate findings and investigate the role this fascial plane has in forming an effective barrier to spread of malignancy.

Manual Instruments as an Alternative to Drilling for Bony Exposure in Skull Base Surgery: Concept and Technique.

Background Drilling in neurosurgery is an integral part of surgical exposure, especially in skull base approaches and craniovertebral junction (CVJ) surgeries. Most of such drillings are done in close proximity to the neurovascular structures in skull base surgeries and cervical-medullary junction or facet/pedicle in CVJ surgeries. Reluctance to drilling among young neurosurgeons is due to less hands-on experience during training and also, in the early part of the career, due to fear of injury to neurovascular structures. Methods Five commonest bone removals for skull base region and CVJ surgeries that can be safely done using manual instruments were identified based on experiences of senior authors. The authors highlight key technical nuances to widen surgical corridors using manual instruments safely for skull base surgical approaches. Results Basic neuroanatomical concepts and basic physics help in using manual instruments safely for bone removals in various skull base surgical approaches. Conclusions Manual instruments may be used for bone removals in selected skull base surgical approaches, which help young neurosurgeons to perform these surgeries in limited-resource settings.

Harmonic Scalpel-Assisted Endonasal Endoscopic Resection of the Vascular Tumors of the Anterior Skull Base

Vascular tumors represent a challenging pathologic subset for surgical treatment as they show a propensity for profuse bleedings. This is especially applicable to the skull base region, where surgical access is difficult due to its complex anatomy. To overcome this problem, the authors introduced the use of a harmonic scalpel in endoscopic skull base surgery for vascular tumors. Here, the authors report the outcomes of endoscopic harmonic scalpel-assisted surgery in 6 juvenile angiofibromas and 2 hemangiomas. All surgeries were performed using Ethicon Endo-Surgery HARMONIC ACE 5mm Diameter Shears. The median intraoperative blood loss was 400mL (range: 200-1500mL). The median length of hospital stay was 7 days (range: 5-10 days). Recurrence was recorded in 1 patient with juvenile angiofibroma, which was successfully resolved with revision surgery. In this institutional experience, ultrasonic technology showed precise cutting with minimal bleeding, resulting in reduced surgical morbidity compared with conventional endoscopic instruments.

Targeting mTOR Pathway in PTEN Deleted Newly Isolated Chordoma Cell Line.

Chordomas are rare primary malignant tumours of notochordal origin usually arising along the axial skeleton with particular predilection of the skull base and sacrococcygeal region. Albeit usually slow-growing, chordomas can be aggressive mostly depending on their invasive behaviour and according to different histotypes and molecular alterations, including TBXT duplication and SMARCB1 homozygous deletion. Partial or complete PTEN deficiency has also been observed. PTEN is a negative regulator of the Akt/mTOR pathway and hyperactivation of Akt/mTOR in cells lacking PTEN expression contributes to cell proliferation and invasiveness. This pathway is targeted by mTOR inhibitors and the availability of in vitro models of chordoma cells will aid in further investigating this issue. However, isolation and maintenance of chordoma cell lines are challenging and PTEN-deleted chordoma cell lines are exceedingly rare. Hereby, we established and characterized a novel human PTEN-deleted chordoma cell line (CH3) from a primary skull base chordoma. Cells exhibited morphological and molecular features of the parent tumour, including PTEN loss and expression of Brachyury and EMA. Moreover, we investigated the activation of the mTOR pathway and cell response to mTOR inhibitors. CH3 cells were sensitive to Rapamycin treatment suggesting that mTOR inhibitors may represent a valuable option for patients suffering from PTEN-deleted chordomas.

Classification of Endoscopic Transnasal Lateral Skull Base Approaches: Anatomical Study

Endoscopic transnasal approaches (ETAs) to the ventrolateral skull base are commonly classified according to coronal planes or anatomical structures. Our goal is to simplify the description of the ETA to lateral skull base regions in a sequential dissection with correlation to computed tomography, helping in preoperative planning and efficient surgical exposure, and exposing the surgical anatomy limitations. Five freshly injected cadaver heads were dissected using an extended ETA to the lateral skull base. Each specimen underwent a high-resolution computed tomography scan. A classification of the lateral skull base based on well-defined zones was proposed. We divided the lateral target into four different zones, in a craniocaudal orientation: zone 1 is the space lying between the orbital floor superior and the level of the sellar floor inferior, zone 2 is on the coronal plane, located between the level of the sellar floor and the vidian canal, zone 3 is the area lateral to the anterior limb of the petro-occipital fissure, located between the vidian canal and the carotid canal, and zone 4 is the space located between the carotid canal and the extracranial opening of the hypoglossal canal, lateral to the anterior part of the posterior limb of petro-occipital fissure. Multiple previous works have described and classified the coronal plane and its lateral extensions. Our classification system for the proposed lateral zones enables preoperative planning to select a suitable approach. The craniocaudal orientation facilitates the understanding of surgical corridors and tailored exposure.

Evaluation of MRI and transnasal endoscopic surgery for the diagnosis of perineural tumor spread to the skull base

Introduction: Magnetic resonance imaging (MRI) provides information about tumor size and extension, infiltration of major blood vessels and nerves, early bone-marrow infiltration, and lymph node involvement. Transnasal endoscopic approaches are an integral part of the therapeutic arsenal developed to address malignant sinonasal and skull-base neoplasms. Objective: To analyze the use of magnetic resonance imaging in the diagnosis of perineural tumor spread involving the skull base region. Methods: We describe two cases of patients who presented with primary squamous cell carcinoma in the malar region and suspected perineural spread to the skull base on MRI. One frozen cadaver head, were dissected to expose the trigeminal nerve and it branches. Results: MRI showed evidence of perineural spread to the skull base, which was confirmed histopathologically after endoscopic transnasal biopsy. Conclusion: MRI plays an important role in the diagnosis of perineural spread of tumors originating in the nose and skull base. In the two cases reported herein, the diagnostic suspicion raised by MRI was confirmed by histopathological examination. Endoscopic transnasal skull base surgery proved to be an important tool for diagnostic confirmation, with low procedure-associated morbidity. The presence of perineural spread changes the staging and, consequently, the prognosis and treatment of these tumors. Thus, its active search should be encouraged to improve diagnosis and help ensure appropriate treatment. Keywords: endoscopic surgery, magnetic resonance imaging, perineural tumor, bone-marrow infiltration

Petroclival Clinoidal Folds and Relationships with Arachnoidal Membranes and Neural Structures of Anterior and Middle Incisural Spaces: Old Neuroanatomical Terms for a New Neurosurgical Speech in Cadaver Labs with Limited Resources Era. Part I: Osteology and Structural Anatomy of Dura Mater.

Purpose The role of cadaver labs in preparing new generations of effective neurosurgeons is of paramount importance. The Authors describe a personal cadaver lab experience aimed at improving the knowledge of a difficult region of the central skull base. The anterior and middle incisural spaces are regions of remarkable anatomical, and surgical interest due to complex relationships between bony, dural, arachnoidal, and neurovascular structures. The primary purpose of this study is (1) to describe the anatomy of this region with particular emphasis on the relationships between the anterior margin of the free edge of the tentorium and the sphenoid and petrous bone; (2) to identify surgical implications in many different types of neurosurgical procedures dealing with this challenging complex anatomic area.Methods Eight fresh, non-formalin-fixed non-silicon-injected adult cadaver heads and five injected formalin-fixed adult cadaver heads were analyzed in this study.Results The anatomical study was focused on the description of the relationships between bony, dural, arachnoid, and neurovascular structures. Surgical implications are described accordingly.Conclusions Detailed anatomical knowledge of this region finds concrete applications in neurosurgical practice since the anterior and middle incisural spaces are often surgically exposed in neoplastic and vascular diseases.

Correlation between C0–C2 height, occipital-C2 angle and clivus-axial angle: CT-based anatomical study

BackgroundThe anatomical data of the skull base region can guide the process of occipitocervical fusion. This study aim to explore the normal range of C0–C2 height and occipital-C2 angle (OC2A) in healthy adults and the relationship between them and clivus-axial angle (CAA), to provide a reference for clinical application. Materials and methodsThe original computed tomography (CT) data of the cervical spine of 180 healthy adults in our hospital were selected retrospectively. According to gender, they were divided into male (n = 90) and female groups (n = 90) and then into six groups according to different age groups. The C0–C2 height, OC2A, and CAA were measured, respectively. The differences in the measured values between genders and different age groups were compared, and the correlation between C0–C2 height, OC2A, and CAA was analyzed. ResultsIn males and females, the average C0–C2 height is (4.28 ± 0.32) cm and (4.02 ± 0.27) cm, respectively. There was a significant difference in C0–C2 height in gender (P < 0.05). The average CAA of males is (156.53 ± 6.09)°, and that of females is (156.09 ± 5.71)°. There was no significant difference in the measured values of OC2A and CAA between genders and ages (P > 0.05). Correlation analysis shows a low correlation between C0–C2 height and CAA. However, there is a significant linear correlation between OC2A and CAA. ConclusionCT can effectively measure the C0–C2 height, OC2A, and CAA. There is a significant linear correlation between OC2A and CAA. It has theoretical guidance and reference value for the comprehensive selection of OC2A in occipitocervical fusion.