Skull Base Research Articles

3D atlas of the human fetal chondrocranium in the middle trimester

The chondrocranium provides the key initial support for the fetal brain, jaws and cranial sensory organs in all vertebrates. The patterns of shaping and growth of the chondrocranium set up species-specific development of the entire craniofacial complex. The 3D development of chondrocranium have been studied primarily in animal model organisms, such as mice or zebrafish. In comparison, very little is known about the full 3D human chondrocranium, except from drawings made by anatomists many decades ago. The knowledge of human-specific aspects of chondrocranial development are essential for understanding congenital craniofacial defects and human evolution. Here advanced microCT scanning was used that includes contrast enhancement to generate the first 3D atlas of the human fetal chondrocranium during the middle trimester (13 to 19 weeks). In addition, since cartilage and bone are both visible with the techniques used, the endochondral ossification of cranial base was mapped since this region is so critical for brain and jaw growth. The human 3D models are published as a scientific resource for human development.

Rare case of assault with knife penetrating base of the skull – Retrieval and management

Addressing a penetrating injury in the maxillofacial region poses significant challenges for oral and maxilofacial surgeons due to the presence or critical structures. Damage to these structures can lead to varying degrees of impairment and a decreased quality of life for the patient. A 48-year-old individual sustained a stabbing injury to the left side of their face. The knife remained lodged inside for 7 h until they were admitted to the trauma unit. The assailant had unsuccessfully attempted to remove the weapon by bending its handle. Following thorough examinations to pinpoint the exact location of the knife, it was safely removed under sedation. The patient experienced successful healing without major complications. The minimisation of scar tissue was achieved through proper debridement and layered linear wound closure. Subsequently, the patient was transferred to the general ward for monitoring and prescribed antibiotics to prevent wound infection. This report includes a detailed account of the weapon retrieval process and is management, along with a review of relevant literature Reconstruction of complicated facial wounds is difficult for surgeons, and early treatment is necessary to avoid additional harm.

Shaping the curve from the microscopic transsphenoidal to the endoscopic endonasal approach for the sellar region.

This study aimed to investigate the limitations, barriers, and complications in the early transition from the microscopic transsphenoidal approach (MTA) to the endonasal endoscopic approach (EEA) to the skull base in our institution. Technical challenges, as well as clinical features and complications, were compared between MTA, EEA, and mixed cases during the early surgical curve. The period from the early learning curve was 1 year until the EEA protocol was used routinely. A total of 34 patients registered a resection using a transsphenoidal approach. Eighteen patients underwent EEA, 11 underwent MTA, and five underwent a mixed endonasal and microscopic approach. Non-significant differences were found in endocrine outcomes between the three groups. Patients with unchanged or improved visual function were higher in the EEA group (p = 0.147). Non-significant differences were found in terms of the extent of resection (EOR) between groups (p = 0.369). Only 1 (2.9%) patient in the whole series developed a post-operative CSF leaking that resolved with medical management, belonging to the EEA group (5.5%). The early phase of the learning curve did not affect our series significantly in terms of the EOR, endocrine status, and visual outcomes.

Foramina and canals of the skull base in Holstein cow: a computed tomography study

Foramina and canals of the skull base in Holstein cow: a computed tomography study

The investigation of cranial fossae in the intracranial cavity of fixed cadaveric skull bases: associations with sex, laterality, and clinical significance.

Our study aims to investigate three parts of the intracranial cavity, their distances to essential anatomical landmarks, and the correlations between these distances with sex, laterality, and surgical significance. The cranial nerve foraminae and essential surgical landmarks of each fossa were investigated bilaterally in 30 adult formalin-fixed cadaveric heads. Measurements, including lengths, depths, diameters, and horizontal distances to each other, to the midline of the skull, and to the outer lateral margin of the skull, were recorded on both sides. The optic canal (OC) depth, internal auditory meatus (IAM) width, CNVII and CNIX diameters, and accessory hypoglossal canal (HC) distance were significantly greater on the left side (p < 0.05). CNVI length, CNV diameter, CNXI length, and the distances of the HC and accessory HC from the skull were significantly greater on the right side (p < 0.05). In males, correlations were found between the length of the left CNVIII and the right IAM diameter (r = 0.864, p = 0.001), right CNVIII length (r = 0.709, p = 0.022), right accessory HC length (r = 0.847, p = 0.016), and right-sided skull distance (r = 0.829, p = 0.042). In females, correlations were noted between IAM depth and length, right IAM location relative to the skull, left CNIX and CNX lengths, left CNXII length, left accessory HC location relative to the skull, and accessory HC length. The findings of the current study indicate inherent asymmetry, sexual dimorphism, and variability in certain cranial nerves among cadaveric heads, which could have implications for surgical procedures, neuroanatomical studies, and clinical assessments. The study revealed side disparities and correlations within cranial fossa formations and essential surgical landmarks in both genders.

Safety and efficacy of hydroset cranioplasty as an adjunct to gasket-seal and nasoseptal flap closure of the skull base. A case-controlled study

Safety and efficacy of hydroset cranioplasty as an adjunct to gasket-seal and nasoseptal flap closure of the skull base. A case-controlled study

FORAMEN MAGNUM – A STUDY ON ITS MORPHOMETRY AMONG THE SOUTH INDIAN POPULATION

Objective: Foramen magnum is an oval opening present in the median region of the posterior cranial fossa of the occipital bone. The lower end of the medulla, meninges, spinal arteries, and spinal roots of accessory nerve pass through the foramen. Morphometry of the foramen magnum is studied for better learning of the structure, but this study helps in planning a safe surgery and exploration in the head-and-neck region. Various surgical approaches of the foramen provide access to the foramina on the base of the skull and prevent broad retraction of the neurovascular structures passing through them, so the morphometric study plays an important role in transcondylar approach. Methods: Fifty dry human skulls available in the Department of Anatomy, Amala Medical College and Hospital, and also at Jubilee Medical College and Hospital, Thrissur were studied for this research work, and results were statistically analyzed. Results: The most common shape of the foramen magnum was oval, the mean of anteroposterior diameter was greater than the mean of transverse diameter, p-value of the diameters was found to be significant, p-value of the mean of foramen magnum index was significant. Conclusion: This study will help the surgeons to effectively plan a surgery at the head and neck site

Primary sinonasal chondroid chordoma in a pediatric patient: a diagnostic challenge

BackgroundChordomas are rare, malignant tumors typically centered in midline structures such as the clivus and sacrum, with peak prevalence in the fourth decade. Clival chordomas may secondarily extend to involve the nasopharynx and nasal cavity; however, primary extra-osseous chordomas are even more uncommon. We present an unusual case of a primary sinonasal chondroid chordoma arising from the maxillary sinus in a 5-year-old child. This is the second case of primary sinonasal chordoma reported in the literature so far, after Tao ZZ et al. and the first case of the chondroid variant.Case presentationA 5-year-old male presented with right-sided nasal obstruction, nasal congestion, and snoring for 2 months. Physical examination showed a reddish polypoidal mass in the right nasal cavity obstructing the choana with nasal septal deviation toward left side. Radiological examination with CT confirmed the presence of a well-defined, heterogeneously hyperdense lobulated mass in right maxillary sinus extending into right nasal cavity with intralesional coarse calcifications. MRI revealed expansile solid altered signal intensity mass, which appears to be isointense on T1-weighted imaging (T1WI) and heterogeneously hyperintense on T2-weighted imaging (T2WI) with a heterogeneous honeycomb pattern of enhancement. Differentials considered were rhabdomyosarcoma, nasopharyngeal carcinoma, and neuroblastoma metastasis. However, the lesion was pathologically proven as a chondroid chordoma. No association with skull base or clival lesion was found on review.ConclusionsPrimary sinonasal chordomas are rare in occurrence but should be considered a differential for sinonasal masses in the presence of characteristic MRI features, despite their uncommon location.

How to do it: excision of carotid space tumours in proximity to skull base

How to do it: excision of carotid space tumours in proximity to skull base

Severe pneumocranium after gamma knife stereotactic radiosurgery for brain metastasis: A case report and literature review.

Gamma knife stereotactic radiosurgery (GKRS) is a recognized safe and effective treatment for brain metastasis; however, some complications can present significant clinical challenges. This case report highlights a rare occurrence of cerebrospinal fluid (CSF) leakage and pneumocranium following GKRS, emphasizing the need for awareness and prompt management of these complications. A 35-year-old male with a history of malignant neoplasm of the lip in 2015 and perineural spread of malignancy into the left cavernous sinus was treated with GKRS in 2017. The patient was admitted emergently 39 days after discharge due to persistent headache and dizziness. Brain computed tomography (CT) revealed diffuse bilateral pneumocranium alongside an observation of CSF leakage. A surgical procedure involving a left frontal-temporal craniotomy was performed to excise a residual skull base tumor and repair the dura, guided by a navigator system. The conclusive pathological assessment revealed the presence of squamous cell carcinoma markers. The patient exhibited excellent tolerance to the entire procedure and experienced a prompt and uneventful recovery process. After surgery, the symptoms alleviated and CSF leak stopped. The follow-up image showed the pneumocranium resolved. Pneumocranium due to early-stage post-GKRS is uncommon. The rapid tumor shrinkage and timing of brain metastasis spreading through the dura can lead to CSF leak and pneumocranium. We reviewed current treatment options and presented a successful craniotomy-based dura repair case.

Surgical Outcomes following Reoperation for Recurrent Intracranial Meningiomas.

Background: We sometimes encounter refractory meningioma cases that are difficult to control, even after achieving a high resection rate or following radiation therapy (RT). In such cases, additional surgical resection might be attempted, but reports regarding outcomes of re-do surgery for recurrent meningiomas are scarce. Methods: This study was a retrospective review of patients who underwent re-do surgery for recurrent meningiomas. The risks of re-doing surgery were statistically analyzed. A comparative analysis between the patients who underwent primary surgery for intracranial meningiomas was also performed. Twenty-six patients underwent re-do surgeries for recurrent meningiomas. Results: At first re-do surgery, gross total resection was achieved in 20 patients (77%). The disease-free survival rate after the first re-do surgery was calculated as 73/58/44% at 1, 2, and 5 years, respectively. A significant factor affecting longer disease-free survival was WHO Grade 1 diagnosis at first re-do surgery (p = 0.02). Surgery-related risks were observed in 10 patients presenting a significant risk factor for skull base location (p = 0.04). When comparing with the risk at primary surgery, the risks of surgical site infection (p = 0.04) and significant vessel injury (p < 0.01) were significantly higher for the re-do surgery. Conclusions: Re-do surgery could increase surgery-related risks compared to the primary surgery; however, it could remain a crucial option, while the indication should be carefully examined in each case.

The impact of obesity on rates of post-operative CSF leak following endoscopic skull base surgery: results from a prospective international multi-centre cohort study.

Post-operative CSF leak is the major source of morbidity following transsphenoidal approaches (TSA) and expanded endonasal approaches (EEA) to lesions of the sella turcica and the ventral skull base. There are conflicting reports in the literature as to whether obesity (BMI ≥30) is a risk factor for this complication. We aimed to evaluate data collected as part of prospective multi-centre cohort study to address this question. The CRANIAL (CSF Rhinorrhoea After Endonasal Intervention to the Skull Base) study database was reviewed and patients were divided into obese and non-obese cohorts. Data on patient demographics, underlying pathology, intra-operative findings and skull base repair techniques were analysed. TSA were performed on 726 patients, of whom 210 were obese and 516 were non-obese. The rate of post-operative CSF leak in the obese cohort was 11/210 (5%), compared to 17/516 (3%) in the non-obese cohort, which was not statistically significant (χ2 = 1.520, p=0.217). EEA were performed on 140 patients, of whom 28 were obese and 112 were non-obese. The rate of post-operative CSF leak in the obese cohort was 2/28 (7%), which was identical to the rate observed in the non-obese cohort 8/112 (7%) Fisher's Exact Test, p=1.000). These results persisted following adjustment for inter-institutional variation and baseline risk of post-operative CSF leak. CSF leak rates following TSA and EEA, in association with modern skull base repair techniques, were found to be low in both obese and non-obese patients. However, due to the low rate of post-operative CSF leak, we were unable to fully exclude a small contributory effect of obesity to the risk of this complication.

Handheld robotic device for endoscopic neurosurgery: system integration and pre-clinical evaluation.

The Expanded Endoscopic Endonasal Approach, one of the best examples of endoscopic neurosurgery, allows access to the skull base through the natural orifice of the nostril. Current standard instruments lack articulation limiting operative access and surgeon dexterity, and thus, could benefit from robotic articulation. In this study, a handheld robotic system with a series of detachable end-effectors for this approach is presented. This system is comprised of interchangeable articulated 2/3 degrees-of-freedom 3 mm instruments that expand the operative workspace and enhance the surgeon's dexterity, an ergonomically designed handheld controller with a rotating joystick-body that can be placed at the position most comfortable for the user, and the accompanying control box. The robotic instruments were experimentally evaluated for their workspace, structural integrity, and force-delivery capabilities. The entire system was then tested in a pre-clinical context during a phantom feasibility test, followed up by a cadaveric pilot study by a cohort of surgeons of varied clinical experience. Results from this series of experiments suggested enhanced dexterity and adequate robustness that could be associated with feasibility in a clinical context, as well as improvement over current neurosurgical instruments.

The Prevalence of the Middle Clinoid Process: A Cross-Sectional Comparative Study in Patients with and without Pathology of the Sella Turcica.

Background The middle clinoid process (MCP), particularly caroticoclinoid ring (CCR) type of the MCP, is an important part of the sphenoid bone for skull base surgery. Previous studies have shown a wide range of MCP prevalence affected by various factors. However, no study has investigated the association between the MCP and the presence of sellar lesions. Objectives The main aim of this study was to evaluate the prevalence of the MCP in the Thai population and factors associated with its presence. Materials and Methods We conducted a cross-sectional study on 400 sides from 200 patients (100 with and 100 without sellar lesions) using cranial computerized tomography scans. Demographic data and MCP characteristics were collected. The association between individual variables and the presence of the MCP was determined by univariate and multivariate analysis. Results The MCP was identified in 168 of 400 sides (42%). Patients with sellar lesions had a significantly lower prevalence of the MCP compared with normal controls (29.5% versus 54.5%, p < 0.001). Of all MCP only 6% were the CCR type. Univariate and multivariate analysis showed that the absence of the sellar lesion was the only factor significantly associated with presence of the MCP (odds ratio: 2.86; 95% confidence interval: 1.90-4.32; p < 0.001). Conclusion The prevalence of the MCP was relatively high in the Thai population, while the prevalence of the CCR was relatively low compared with previous studies. The absence of sellar lesions was the only factor associated with the presence of the MCP.

A multi-institutional machine learning algorithm for prognosticating facial nerve injury following microsurgical resection of vestibular schwannoma

Vestibular schwannomas (VS) are the most common tumor of the skull base with available treatment options that carry a risk of iatrogenic injury to the facial nerve, which can significantly impact patients’ quality of life. As facial nerve outcomes remain challenging to prognosticate, we endeavored to utilize machine learning to decipher predictive factors relevant to facial nerve outcomes following microsurgical resection of VS. A database of patient-, tumor- and surgery-specific features was constructed via retrospective chart review of 242 consecutive patients who underwent microsurgical resection of VS over a 7-year study period. This database was then used to train non-linear supervised machine learning classifiers to predict facial nerve preservation, defined as House-Brackmann (HB) I vs. facial nerve injury, defined as HB II–VI, as determined at 6-month outpatient follow-up. A random forest algorithm demonstrated 90.5% accuracy, 90% sensitivity and 90% specificity in facial nerve injury prognostication. A random variable (rv) was generated by randomly sampling a Gaussian distribution and used as a benchmark to compare the predictiveness of other features. This analysis revealed age, body mass index (BMI), case length and the tumor dimension representing tumor growth towards the brainstem as prognosticators of facial nerve injury. When validated via prospective assessment of facial nerve injury risk, this model demonstrated 84% accuracy. Here, we describe the development of a machine learning algorithm to predict the likelihood of facial nerve injury following microsurgical resection of VS. In addition to serving as a clinically applicable tool, this highlights the potential of machine learning to reveal non-linear relationships between variables which may have clinical value in prognostication of outcomes for high-risk surgical procedures.

Síndrome de Maffucci e condrossarcoma

Introduction: Maffucci syndrome is characterized by multiple subcutaneous enchondromas and can be complicated by skull base chondrosarcoma, a rare malignant tumor that produces a cartilaginous matrix that invades the cortical bone and medullary tissue. Objective: To review this syndrome and its correlation with chondrosarcoma. Method: Narrative review based on published information with material for reading and analysis selected from virtual publishers, SciELO, VHL - Virtual Health Library, Pubmed and Scopus. Initially, a search was carried out for descriptors related to the topic, existing in DeCS/MESH using the following terms: “skull base tumor, chondrosarcoma, Maffucci syndrome” with AND or OR search, considering the title and/or summary. Result: After analyzing the relevant articles, 40 articles were selected and included in this review. Conclusion: Skull base lesions should be highly suspected in patients with Maffucci syndrome.

Role of surgery along with antimicrobials in refractory skull base osteomyelitis-A prospective observational study.

Study aimed to ole of surgery along with antimicrobials to improve clinical outcomes in treating refractory cases of skull base osteomyelitis (SBO). A prospective observational study in a tertiary care centre with 70 SBO patients meeting eligibility criteria. The study population comprised 35 patients refractory to systemic antimicrobials of at least 4 weeks duration who later underwent surgery in addition to medication (surgical group). They were compared with a medical group that responded to medications alone. The outcome variables studied were the resolution of clinical features (pain, discharge, radiology, and inflammatory markers), culture yield, and total duration of treatment. According to our study, relief of pain was faster in the surgical group (1.66 against 4.57 months) with statistical significance (p < 0.001). Relief of symptoms (p < 0.001), radiological improvement (p = 0.001), and normalising of inflammatory markers (p < 0.001) were better in the surgical group than in the medical group. The duration of treatment was an average of 9.2 months in the surgical group compared to 11.3 months in the medical group (p = 0.019). Microbial culture from deep tissue sampling was positive in 24 surgical patients (68.57%). The treatment response in selected patients of refractory SBO who underwent surgery along with antimicrobials was better than the group who responded to antimicrobials alone. Surgery provided higher microbial yield resulting in culture-specific antimicrobials. The surgical group observed faster relief of symptoms, reduced hospital stay, and total treatment duration.

Pediatric cerebrospinal fluid rhinorrhea caused by low flow vascular anomaly of the temporal bone: A case series

ObjectiveAtraumatic cerebrospinal fluid (CSF) rhinorrhea is uncommon in children and necessitates a multi-disciplinary evaluation for an etiology. Underlying osseous abnormality due to extensive or multifocal low flow vascular anomaly should be considered as a potential cause of spontaneous CSF leak. Treatment of multifocal low flow vascular anomalies may include medical and surgical approaches. In this series, we seek to determine the presenting signs and symptoms and medical and surgical treatment options for multifocal or extensive low flow vascular anomalies. MethodsA retrospective case series at a quaternary care children's hospital was compiled. All children with CSF rhinorrhea diagnosed and treated for multifocal low flow vascular anomalies at our institution were included. A total of four patients were identified. ResultsAll four patients had delay in initial diagnosis of underlying cause of meningitis and CSF rhinorrhea. Average age at diagnosis of multifocal low flow vascular anomaly was 7 years. This was on average 4 years after initial presentation for medical attention. Treatment approach was multidisciplinary and included medical management with sirolimus and bisphosphonates as well as surgical approaches to the skull base (lateral and anterior) to prevent CSF egress. ConclusionConsideration of multifocal low flow vascular anomaly should be included in any pediatric patient presenting with CSF rhinorrhea.

Chondrossarcoma of the skull base incidentally discovered through Maffucci Syndrome

Introdução: A Síndrome de Maffucci (SM) é uma displasia mesodérmica não hereditária congênita associada a malformações venosas cutâneas com discondroplasia. Objetivo: revisar a síndrome de MAffucci e apresentar um caso no qual o condrossarcoma assintomático da base do crânio foi diagnosticado como achado casual e tratado. Resultados: Caracteriza-se por ser uma enfermidade rara com menos de 200 casos descritos pela literatura, não havendo estatísticas sobre sua epidemiologia e prevalência. A Síndrome de Maffucci tem como principal diagnóstico diferencial a Síndrome de Ollier. Outras patologias também devem ser pensadas diante do quadro apresentado, como o sarcoma de kaposi, síndrome de Klippel-Trenaunay-Weber,síndrome de Proteus e doença de Gorham. Conclusão: deve-se ter alto grau de suspeita de lesões da base do crânio em pacientes com síndrome de maffucci.

The risk of radiosurgery as primary treatment for supposedly benign tumors of the skull base

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