Skull Base Anatomy Research Articles

Exposure region of the Kawase approach and its correlation with skull base anatomy: An evaluation with digital models.

The Kawase approach is one of the most used trajectories in skull base surgery. The exposure range of the approach and its correlation with skull base anatomy still demand more exploration. With the help of digital rebuilding, analysis, and measurement, we evaluated the exposure range of the Kawase and extended Kawase approaches and analyzed the correlation between the exposure range and the variants of the petrosal and clival anatomy. The finding of the study demonstrated that compared to the sub-temporal approach, the Kawase approach and the extended Kawase approach significantly added the exposure range in the upper, middle, and partial inferior regions of the clivus. The gains in the exposure volume and area are more when the manipulation angle is less than 135°.

A novel 3D surgical neuroanatomy course for medical students: Outcomes from a pilot 6-week elective

BackgroundDeveloping and maintaining a three-dimensional working knowledge of neuroanatomy is an essential skill in neurosurgery. However, conventional 2D head, neck, and neuroanatomy education is typically characterized by the separate rote learning of constituent tissues and often fails to provide learners with a contextual understanding of the relationships between these highly complex and interconnected structures. This can pose a significant challenge to medical students entering neurosurgery who lack a topographic understanding of intracranial anatomy. MethodsWe report on the design and efficacy of a novel 6-part 3D surgical neuroanatomy pilot elective for medical students that utilized a navigation-based pedagogical technique with the goal of providing students with a framework for developing a 3D mental map of the skull base, neurovasculature, ventricular system, and associated brain regions. Students took on the perspective of physically traveling along the paths of key structures with a 360-degree view of surrounding anatomy such that they could appreciate the integration and relative spatial relationships of the varying tissues within the cranium. Mental navigation exercises and pre- and post-course surveys were used to assess students’ baseline and learned familiarity with the different anatomical regions covered. ResultsAt the conclusion of the course, all students were able to successfully complete all of the multifaceted mental navigation exercises. Post-course survey data indicated that respondents perceived significant increases in their knowledge of cranial nerves; anterior, middle, and posterior skull base anatomy; anterior and posterior cranial circulation; and the ventricular system. Conclusion3D navigation-based fly-through instruction is a novel and effective technique for teaching complex anatomy and can provide learners with the foundational skills for developing and maintaining a 3D mental map of intracranial anatomy.

The "Crista Ovale": A Reliable Anatomical Landmark in Transorbital Endoscopic Approaches to the Middle Cranial Fossa.

Transorbital endoscopic approaches (TOEAs) have emerged as adjunct and alternatives for accessing the middle cranial fossa (MCF). Nuances of the skull base anatomy from a ventral transorbital endoscopic viewpoint remain to be fully described. To assess the anatomy of the "crista ovale" (COv), described transcranially as the midsubtemporal ridge (MSR), from a ventral transorbital perspective and evaluate its role as a landmark in TOEA to the MCF. Lateral TOEAs to the MCF were performed in 20 adult cadaveric heads (40 sides). The presence of the COv/MSR was evaluated under endoscopic visualization. Anatomic relationships between COv/MSR and surrounding structures were assessed. The presence of COv/MSR was also examined in 30 cadaveric head computed tomography (CT) scans (60 sides). The COv/MSR was identified in 98% (39/40) of sides at the MCF, as 1 of 4 major configurations. The COv/MSR was found anterolateral to the foramen ovale and foramen spinosum (mean distance: 9.2 ± SD 2.4 mm and 12.3 ± SD 2.6 mm, respectively) directly anterior or anteromedial to the petrous apex (mean distance: 26.2 ± SD 2.6 mm) and at a mean 47.6 ± SD 4.7 mm from the approach's surgical portal. It was recognized in 95% (57/60) of CT scans. The COv/MSR can be readily identified during TOEA to the MCF and on CT. It serves as a reliable landmark to localize the foramen ovale, foramen spinosum, and petrous apex. Further studies may confirm its surgical significance in transorbital endoscopic procedures.

Outcomes Following Proton Radiotherapy for Pediatric Salivary Gland Tumors

<h3>Purpose/Objective(s)</h3> In contrast to adult salivary gland tumors, our institutional guidelines in children utilize lower radiation doses, smaller target margins, and proton therapy to minimize radiation to the developing skull base anatomy. Furthermore, we do not routinely recommend prophylactic nodal irradiation or elective neck dissection. Previous series of children treated with adjuvant radiation therapy report 5-year local control ∼85%. Herein we report treatment outcomes using our pediatric approach. <h3>Materials/Methods</h3> Twenty-seven consecutive pediatric patients were treated with proton therapy between 2006 and 2020 for mucoepidermoid carcinoma (n= 13), acinic cell carcinoma (n= 5), adenoid cystic carcinoma (n= 4), pleomorphic adenoma (n= 2), myoepithelial carcinoma (n= 1), adenocarcinoma (n= 1), and sialoblastoma (n= 1) at our institution. The 8 patients with radiographic lymphadenopathy (cN1) underwent neck dissection prior to presentation (7/8 selective dissections involving <4 nodal levels). The most common indications for adjuvant radiotherapy were microscopic positive or close (<1 mm) margins (n=15), perineural invasion (PNI; n=9), high-grade histology (n=6), and gross residual disease (n=4). Radiotherapy was delivered in sequential plans using 2 clinical target volumes (CTV1, CTV2). Gross tumor volume (GTV=CTV2) included the residual tumor and tumor bed. CTV1 received 50.4 Gy and was defined as GTV + 1 cm and the at-risk neck if indicated. The dose to CTV2 depended on histology, grade, and margin status. The median total dose was 64.8 Gy (range, 61.2-70.2 Gy). Only 3 patients underwent prophylactic nodal irradiation. Toxicity data was graded based on CTCAE v3 or v4 using patient-reported and physician-reported outcomes according to our prospective outcome registry. <h3>Results</h3> The median follow-up was 5.5 years. Overall survival was 100% and local control was 96% with a single local recurrence seen in a patient with gross unresectable disease. There were no nodal recurrences. In terms of acute toxicity, 3 patients experienced mucositis requiring opioid pain medication and 2 patients developed grade 3 radiation dermatitis. The most serious late toxicity involved the ear or auditory system including 4 patients requiring hearing aids, 1 with chronic otitis media, 1 with osteonecrosis of the mastoid bone, and 1 with external ear canal stenosis. Four additional patients reported variable hearing loss not requiring hearing aids. Other serious late toxicity included 1 patient with persistent trismus, 1 with growth hormone deficiency, and 1 with excessive dental caries along the ipsilateral maxilla. No secondary malignancies nor toxicities grade ≥ 4 were seen. <h3>Conclusion</h3> An approach of conservative neck management and moderate-dose proton radiotherapy delivered to small volumes resulted in excellent disease control and limited toxicity in children with common salivary gland tumors at elevated risk of local recurrence.

Endoscopic transorbital avenue to the skull base: Four-step conceptual analysis of the anatomic journey.

BackgroundIn the last decades, skull base surgery had passed through an impressive evolution. The role of neuroanatomic research has been uppermost, and it has played a central role in the development of novel techniques directed to the skull base. Indeed, the deep and comprehensive study of skull base anatomy has been one of the keys of success of the endoscopic endonasal approach to the skull base. In the same way, dedicated efforts expended in the anatomic lab has been a powerful force for the growth of the endoscopic transorbital approach to the lateral skull base.Therefore, in this conceptual paper, the main steps for the anatomic description of the endoscopic transorbital approach to the skull base have been detailed.MethodsThe anatomic journey for the development of the endoscopic transorbital approach to the skull base has been analyzed, and four “conceptual” steps have been highlighted.ResultsAs neurosurgeons, the eyeball has always represented a respectful area: to become familiar with this complex and delicate anatomy, we started by examining the orbital anatomy on a dry skull (step 1). Hence, step 1 is represented by a detailed bone study; step 2 is centered on cadaveric dissection; step 3 consists in 3D quantitative assessment of the novel endoscopic transorbital corridor; and finally, step 4 is the translation of the preclinical data in the real surgical scenario by means of dedicated surgical planning.ConclusionsThe conceptual analysis of the anatomic journey for the description of the endoscopic transorbital approach to the skull base resulted in four main methodological steps that should not be thought strictly consequential but rather interconnected. Indeed, such steps should evolve following the drives that can arise in each specific situation. In conclusion, the four-step anatomic rehearsal can be relevant for the description, diffusion, and development of a novel technique in order to facilitate the application of the endoscopic transorbital approach to the skull base in a real surgical scenario.

The impact of expanded endoscopic approaches on oncologic and functional outcomes for clival malignancies:a case series.

Clival malignancies pose particular surgical challenges due to complex skull base anatomy and the involvement of vital neurovascular structures. While endoscopic endonasal approached are widely used, the outcomes for clival malignancies remain poorly understood. In this study we assessed the impact of endoscopic and open surgical approaches on PFS, time to initiation of radiotherapy, KPS, and GTR rates for clival malignancies. A retrospective case series for clival malignancies operated between 1993 and 2019 was conducted. Inclusion criteria were age over 18 and a follow-up of at least a 6months. Statistical analyses were conducted using STATA version 15 statistical software package StataCorp. For the whole cohort (113 patients), and for upper and middle lesions, open surgical approaches increased odds of disease progression, compared to EEA (HR 2.10 to HR 2.43), p < 0.05. EEA had a shorter time interval from surgery to initiation of radiotherapy. No difference in 6 and 12month KPS was found between surgical groups. Patients undergoing open surgery were less likely to achieve GTR for upper clival lesions. EEA was found to be associated with increased PFS, for upper and middle clival malignancies. The time to initiation of radiotherapy was shorter for patients undergoing EEA compared to open surgery for patients with middle clival involvement. GTR rates were found to be significantly better with EEA for patients with upper clival malignancies.

Approach selection for resection of petroclival meningioma.

Petroclival meningiomas are surgically challenging tumors because of their deep location and involvement of critical neurovascular structures. A variety of approaches have been described, and selection of approach should be tailored to the location of the tumor relative to neurovascular structures and surgical experience. The authors present two patients with petroclival meningiomas with varying relationships to cranial nerves and skull base anatomy who underwent endoscopic endonasal and open petrosectomy approaches, to demonstrate the complementarity of the endonasal transpetrous and open transpetrosal corridors. Proficiency in both open and endonasal approaches is critical to appropriate approach selection and maximal safe resection.The video can be found here: https://stream.cadmore.media/r10.3171/2022.1.FOCVID21252

Evaluation of the Keros Classification of Olfactory Fossa by CT Scan in Qassim Region.

ObjectiveEndoscopic sinus surgery (ESS) is now the most often utilized surgical procedure for treating chronic sinonasal disorders. Therefore, anatomical knowledge of its variations is required to avoid serious postoperative complications. Thus, careful preoperative examination for patients with a paranasal sinus CT scan is necessary. Our study aims to evaluate Keros types and their incidence by evaluating the olfactory fossa (OF) depth according to the Keros classification on paranasal sinus CT scans in the Qassim region.MethodsA cross-sectional study was conducted between January 2018 and January 2021 on 148 patients with an average age of 32.59 ± 6.1 who had a non-enhanced paranasal sinus CT scan evaluated by a consultant radiologist using the PACS (picture archiving and communication system) software. Statistical analysis was performed using the statistical software package SPSS version 25 (IBM Corp., Armonk, NY). The chi-square test was used to analyze the relationship between findings and patient characteristics. Also, a p-value of < 0.05 was kept in mind to indicate statistical significance.ResultsThe average depth of the right olfactory fossa (OF) was 5.1 mm with a standard deviation of 1.756 while it was 5.28 on the left side with a standard deviation of 1.66. According to the Keros classification, out of a total of 296 OF, type 1 was found in 84 (28.4%), type 2 in 188 (63.5%), and type 3 in 24 (8.1%). Consequently, the majority of cases were of type 2. Also, we found that type 2 was the most common on both sides in males, whereas, in females, type 2 was the most common on the left side and type 1 on the right side.ConclusionThe study of the Keros classification is significantly important to evaluate the anatomy of the anterior skull base and give the surgeon knowledge about the depth of the olfactory fossa. Thus, a preoperative CT scan of the paranasal sinus is critical to ensure that the surgical approach is properly planned and possible surgical complications related to the anatomy of this area can be prevented. Our study showed that Keros type II is the most common, followed by type I and then type III.

Imaging of the Postoperative Skull Base and Cerebellopontine Angle.

For pathologic conditions affecting the skull base and cerebellopontine angle, imaging techniques have advanced to assess for residual disease, disease progression, and postoperative complications. Knowledge regarding various surgical approaches of skull base tumor resection, expected postoperative appearance, and common postsurgical complications guides radiologic interpretation. Complexity of skull base anatomy, small size of the relevant structures, lack of familiarity with surgical techniques, and postsurgical changes confound radiologic evaluation. This article discusses the imaging techniques, surgical approaches, expected postoperative changes, and complications after surgery of the skull base, with emphasis on the cerebellopontine angle, anterior cranial fossa, and central skull base regions.

Sellar, suprasellar, and parasellar masses: Imaging features and neurosurgical approaches.

The sellar, suprasellar, and parasellar space contain a vast array of pathologies, including neoplastic, congenital, vascular, inflammatory, and infectious etiologies. Symptoms, if present, include a combination of headache, eye pain, ophthalmoplegia, visual field deficits, cranial neuropathy, and endocrine manifestations. A special focus is paid to key features on CT and MRI that can help in differentiating different pathologies. While most lesions ultimately require histopathologic evaluation, expert knowledge of skull base anatomy in combination with awareness of key imaging features can be useful in limiting the differential diagnosis and guiding management. Surgical techniques, including endoscopic endonasal and transcranial neurosurgical approaches are described in detail.

Imaging of Skull Base Trauma: Fracture Patterns and Soft Tissue Injuries.

This article provides an overview of the patterns of skull base trauma and provides a review of the pertinent soft tissue injuries and complications that can ensue. A brief review of skull base anatomy is provided with subsequent focus on the important findings in anterior, central, and posterior skull base trauma.

Operative Anatomy of the Skull Base: 3D Exploration with a Highly Detailed Interactive Atlas.

Objective We evaluated the usefulness of a three-dimensional (3D) interactive atlas to illustrate and teach surgical skull base anatomy in a clinical setting. Study Design A highly detailed atlas of the adult human skull base was created from multiple high-resolution magnetic resonance imaging (MRI) and computed tomography (CT) scans of a healthy Caucasian male. It includes the parcellated and labeled bony skull base, intra- and extracranial vasculature, cranial nerves, cerebrum, cerebellum, and brainstem. We are reporting retrospectively on our experiences with employing the atlas for the simulation and teaching of neurosurgical approaches and concepts in a clinical setting. Setting The study was conducted at the University Hospital Mainz, Germany, and Hirslanden Hospital, Zürich, Switzerland. Participants Medical students and neurosurgical residents participated in this study. Results Handling the layered graphical user interface of the atlas requires some training; however, navigating the detailed 3D content from intraoperative perspectives led to quick comprehension of anatomical relationships that are otherwise difficult to perceive. Students and residents appreciated the collaborative learning effect when working with the atlas on large projected screens and markedly improved their anatomical knowledge after interacting with the software. Conclusion The skull base atlas provides an effective way to study essential surgical anatomy and to teach operative strategies in this complex region. Interactive 3D computer graphical environments are highly suitable for conveying complex anatomy and to train and review surgical concepts. They remain underutilized in clinical practice.

Posterior Skull Base Anatomy and Pathology

A posterior skull base lesion is an uncommon radiological finding that may be noted incidentally or during targeted imaging of patients with clinical symptoms attributable to the lesion. It may be inflammatory or neoplastic in etiology, or may simply be an anatomic variant or a "don't-touch" lesion that should not be misinterpreted as something more ominous. A systematic approach to the evaluation of the posterior skull base is therefore required in order to differentiate lesions requiring immediate attention from those requiring a less urgent course of action or none at all. This review will focus on the imaging features of pathologic conditions that are more commonly encountered in posterior skull base CT and MR examinations.

Virtual Anatomist: A Deep Learning‐based Smartphone Application to Identify Complex Anatomical Features in Augmented Reality

This study pertains to the development of a smartphone mixed-reality (MR) educational app intended to improve the experience of using physical 3D models in classrooms by identifying and labeling various anatomical features on models, built on a deep-learning based computer vision framework. Research at the intersection of MR applications and anatomy education has routinely demonstrated a role for new MR-based modalities in improving anatomy education, but most MR apps rely on custom illustrated projections of 3D-models into user and screen space. These virtual assets are subject to device-intrinsic or developer-based differences in display fidelity and specimen art quality. An intrinsic barrier is present in the development of digital 3D models, which are not trivial to create. Existing evidence also suggests that virtual models may produce inferior results for learning in some use-cases compared to existing physical models. Such evidence forms a case to instead place emphasis on improving the experience of using existing physical models. The described application is hence intended to improve the experience of using real models by labeling anatomical features of interest for the user. The current implementation of the application is trained solely on skull-base anatomy (with class labels including selected bones of the calvarium, paranasal sinuses, and skull processes), but may be extended to other anatomical areas of interest. This labeling is made possible by a hybrid depth-estimation and semantic segmentation-focused machine learning (ML) architecture, which is deployed on consumer-grade smartphones to promote student uptake. When creating ML-based tools, the primary barrier is often the generation of quality ground truth data. Image collections of anatomical specimens must ideally be taken under different conditions, with different augmentations applied to images to improve the ability of the application to robustly recognize and label different parts of a specimen. Manual collection and annotation of the hundreds or thousands of such images required for training is infeasible. However, using procedurally generated images from a 3D-modelled skull (here, in the open-source computer graphics software Blender), developers can produce arbitrarily large, photorealistic ground-truth training datasets with pixel-perfect semantic segmentation of anatomical features. The generalizability of the ML classifier to different models was improved through augmentation of individual renders in Blender by randomizing the model textures; lighting; background environments; skull topology via displacement mapping; the use of “distractor” objects in renders; and camera angles. This work demonstrates the feasibility of developing an anatomical landmark classifier from RGB-image data, trained on fully synthetic data. Future steps include optimization of data augmentations to emphasize shape recognition over texture recognition, formal characterization of segmentation accuracy on cadaveric specimens, and to train alternative models to incorporate depth data, to leverage depth-sensing capabilities that are available on select higher-end mobile devices.

Central Skull Base Anatomy and Pathology: A Review

The central skull base is an anatomically complex region of the head and neck which hosts a variety of neoplastic, vascular, infectious, inflammatory, and developmental pathologies. Evaluation of its intricate anatomy requires dedicated and complementary imaging modalities of MRI and CT. This article will provide a brief review of the anatomy of the central skull base, followed by an overview of common pathologies encountered in this region and their characteristic radiological characteristics.

CT of Skull Base Fractures: Classification Systems, Complications, and Management.

As advances in prehospital and early hospital care improve survival of the head-injured patient, radiologists are increasingly charged with understanding the myriad skull base fracture management implications conferred by CT. Successfully parlaying knowledge of skull base anatomy and fracture patterns into precise actionable clinical recommendations is a challenging task. The authors aim to provide a pragmatic overview of CT for skull base fractures within the broader context of diagnostic and treatment planning algorithms. Laterobasal, frontobasal, and posterior basal fracture patterns are emphasized. CT often plays a complementary, supportive, or confirmatory role in management of skull base fractures in conjunction with results of physical examination, laboratory testing, and neurosensory evaluation. CT provides prognostic information about short- and long-term risk of cerebrospinal fluid (CSF) leak, encephalocele, meningitis, facial nerve paralysis, hearing and vision loss, cholesteatoma, vascular injuries, and various cranial nerve palsies and syndromes. The radiologist should leverage understanding of specific strengths and limitations of CT to anticipate next steps in the skull base fracture management plan. Additional imaging is warranted to clarify ambiguity (particularly for potential sources of CSF leak); in other cases, clinical and CT criteria alone are sufficient to determine the need for intervention and the choice of surgical approach. The radiologist should be able to envision stepping into a multidisciplinary planning discussion and engaging neurotologists, neuro-ophthalmologists, neurosurgeons, neurointerventionalists, and facial reconstructive surgeons to help synthesize an optimal management plan after reviewing the skull base CT findings at hand. Online supplemental material is available for this article. ©RSNA, 2021.

Ultrasound Doppler examination in the surgical treatment of pituitary adenomas with cavernous sinus extension

Objective: To determine the effectiveness of intraoperative Doppler ultrasound in the surgical treatment of pituitary adenomas with invasive parasellar growth into the cavernous sinus Knosp 3 and Knosp 4. Material and Methods. During 2009–2017, 71 patients with pituitary adenomas (PA) with extension into the cavernous sinus Knosp 3 and Knosp 4 were retrospectively reviewed. According to the size PA were divided into pituitary macroadenomas, (from 10 to 40 mm) in 45 (63.4%) patients, and giant PA (over 40 mm) – in 26 (36.6%) patients. Cavernous sinus invasion Knosp 3 and 4 was identified in 47 (66.2%) and 24 (33.8%) patients respectively. Non-secreting PA - 43 (60.5%) patients and hormone-secreting PA - 28 patients (39.4%). Endoscopic endonasal trassphenoidal (EET) approach was used in all cases. Laterally expanded EET (LEEET) approach was used in 29 cases. Intraoperative Doppler ultrasound (IDUS) was used in 36 (51%) cases. Results. Intraoperative Doppler ultrasound was used in cases of Knosp 3 extension in 23 (32.4%) cases and in Knosp 4 - in 13 (18.3%) cases. Gross total resection, including extension into the cavernous sinus using IDUS was achieved in 22 (62.7%) patients. In cases where IDUS was not used, gross total resection was achieved in 19 (52.7%) cases. In cases where the IDUS was not used, recurrence rate was 7.3%, with IDUS - 5%. Biochemical remission was achieved in 22 (78.6%) cases. Liquorrhea nasalis after surgery was observed in 6 (8.4%) cases, meningoencephalitis - in 1 (1.4%) case, oculomotor palsy -3 (4.2%) cases. Conclusions. Intraoperative Doppler ultrasound is an informative method that provides safe resection of pituitary adenomas with cavernous sinus extension with a low level of possible postoperative complications. Parasellar extension of Pituitary adenomas into the cavernous sinus Knosp 4 significantly reduces the possibility of gross total resection. However, the use of intraoperative ultrasound makes it possible to determine safe boundaries for manipulation both medially and laterally from the internal carotid artery, increasing the level of radicality and the duration of clinical remission. Intraoperative Doppler ultrasound during endoscopic endonasal transsphenoidal surgery of pituitary adenomas with parasellar extension allows to identify the internal carotid artery in the tumor stroma with the existing changed skull base anatomy. Dura incision under intraoperative Doppler ultrasound reduces the risk of internal carotid artery injury.

Intracranial Solitary Fibrous Tumor of the Skull Base: 2 Cases and Systematic Review of the Literature

Intracranial solitary fibrous tumors (ISFTs) are rare neoplasms of mesenchymal origin that originate from the meninges. ISFTs of the skull base can be challenging to treat, as resection can be complicated by skull base anatomy. We present 2 cases of ISFT, the first manifesting with compressive cranial neuropathy from Meckel cave involvement and the second a posterior fossa lesion causing symptomatic hydrocephalus. A systematic review was performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The PubMed database was queried with title/abstract keywords "intracranial," "solitary fibrous tumor," "hemangiopericytoma," "SFT," and "HPC." Search results were reviewed to exclude cases not involving the skull base. References from all selected articles were reviewed for potential additional cases. Patient demographic and clinical data from 58 identified skull base cases were collected for qualitative synthesis. Visual disturbances were the most common presenting symptom (30 cases, 52%) followed by headache (22 cases, 38%). The most common site of involvement was the sellar/parasellar region (18 cases, 31%) followed by middle fossa/temporal bone (14 cases, 24%). Resection was performed in 55 cases; gross total resection was reported in 26 cases (45%) and subtotal resection was reported in 21 cases (36%). Tumor recurrence was documented in 15 cases (26%) with median and mean follow-up periods of 16 and 29.9 months, respectively. We discuss presentation, imaging, histopathology, and management considerations for ISFTs while highlighting the potentially complex nature of skull base lesions and need for multidisciplinary approach to treatment.

Skull Base Anatomy in Patients with Bilateral Choanal Atresia: A Radiographic Study.

Introduction The risk of skull base injury during choanal atresia repair can be mitigated via thorough understanding of skull base anatomy. There is a paucity of data describing differences in skull base anatomy between patients with coloboma, heart defects, atresia choanae, growth retardation, genital abnormalities, and ear abnormalities (CHARGE) syndrome and those without. Objectives The aim of this study was to measure nasal and skull base anatomy in patients with isolated bilateral choanal atresia (BCA), CHARGE syndrome, and other syndromic congenital anomalies. Methods Retrospective chart review of patients with bilateral choanal atresia and computed tomography of the face between 2001 and 2019 were evaluated. Choanal width, height, mid-nasal height, and skull base slope were measured radiographically. Differences in anatomy between healthy patients, those with CHARGE syndrome, and those with other congenital anomalies were compared. Results Twenty-one patients with BCA and relevant imaging were identified: 7 with isolated BCA, 6 with CHARGE syndrome, and 8 with other congenital anomalies. A t -test indicated insignificant difference in skull base slope, choanal height, choanal width, or mid-nasal skull base height between isolate BCA cases and patients with any congenital anomaly. When comparing CHARGE to isolated BCA cases, mid-nasal height was shorter in CHARGE patients ( p = 0.03). There were no differences in measurements between patients with congenital anomalies excluding CHARGE ( p > 0.05). Two patients in the congenital anomaly group were found to have bony skull base defects preoperatively. Conclusion This study represents the largest description of skull base and nasal anatomy in patients with CHARGE syndrome and BCA. Surgeons should be aware of the lower skull base in CHARGE patients to avoid inadvertent skull base injury.

Simulation of Pediatric Anterior Skull Base Anatomy Using a 3D Printed Model

The pediatric skull base may present anatomic challenges to the skull base surgeon, including limited sphenoid pneumatization and a narrow nasal corridor. The rare nature of pediatric skull base pathology makes it difficult to gain experience with these anatomic challenges. The objective of this study was to create a 3-dimensionally (3D) printed model of the pediatric skull base and assess its potential as a training tool. Twenty-eight participants at various stages of training and practice were included in our study. They completed a pre- and postdissection questionnaire assessing challenges with endoscopic endonasal skeletonization of the carotid arteries and sella face using the 3D printed model. The majority of participants had completed a skull base surgery fellowship (60.7%), were <5 years into practice (60.7%), and had <10 cases of pediatric skull base experience (82.1%). Anticipated challenges included limitation of maneuverability of instruments (71.4%), narrow nasal corridor and nonpneumatized bone (57.1%). On a scale of 0-10, 10 being very difficult, the average participant expected level of difficulty with visualization was 6.89 and expected level of difficulty with instrumentation was 7.3. On postdissection assessment, there was a nonstatistically significant change to 6.93 and 7.5, respectively. Participants endorsed on a scale of 0-10, 10 being very realistic, an overall model realism of 7.0 and haptic realism of 7.1. A 3D printed model of the pediatric skull base may provide a realistic model to help participants gain experience with anatomic limitations characteristic of the pediatric anterior skull base.