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The orbit is a paired, transversely oval, and cone-shaped osseous cavity bounded and formed by the anterior and middle cranial base as well as the viscerocranium. Its main contents are the anterior part of the visual system, globe and optic nerve, and the associated neural, vascular, muscular, glandular, and ligamentous structures required for oculomotion, lacrimation, accommodation, and sensation. A complex stream of afferent and efferent information passes through the orbit, which necessitates a direct communication with the anterior and middle cranial fossae, the pterygopalatine and infratemporal fossae, as well as the aerated adjacent frontal, sphenoidal, and maxillary sinuses and the nasal cavity. This article provides a detailed illustration and description of the microsurgical anatomy of the orbit, with a focus on the intrinsically complex spatial relationships around the annular tendon and the superior orbital fissure, the transition from cavernous sinus to the orbital apex. Sparse reference will be made to surgical approaches, their indications or limitations, since they are addressed elsewhere in this special issue. Instead, an attempt has been made to highlight anatomical structures and elucidate concepts most relevant to safe and effective transcranial, transfacial, transorbital, or transnasal surgery of orbital, periorbital, and skull base pathologies. [ABSTRACT FROM AUTHOR]

Background We evaluated a transrectus capitis posteriormuscle triangle approach to the posterolateral foramen magnum, occipital condyles, jugular tubercle, and the fourth ventricle. We also assessed factors that affect the amount of bone removal required. Objective To evaluate if the proposed approach is as effective as standard open approaches to expose the lateral portion of the foramen magnum. Methods The proposed minimally invasive fully endoscopic approach was performed in 15 cadaveric specimens using 4-mm (0- and 45-degree) endoscopes. Results Using a 5-cm straight paramedian incision, the rectus capitis posterior minor and major muscles were partially removed unilaterally, providing a corridor through the muscles to reach the foramen magnum region. After meticulous soft tissue dissection, key anatomical landmarks can be identified such as the greater occipital nerve, the vertebral artery that wraps around the atlanto-occipital joint, and the bony protuberance that heralds the occipital condyle. A suboccipital craniotomy associated with the transcondylar, supracondylar or paracondylar approach is performed depending on the amount of bone removal desired to maximize the surgical view. By doing so, the jugular foramen can be exposed laterally as well as the fourth ventricle medially. Conclusion The proposed endoscopic approach can provide access through the transrectus capitis posterior muscle triangle leading directly to the occipital condyle. A stepwise approach is critical to gain a surgical corridor to the inferolateral petroclival region and the fourth ventricle. [ABSTRACT FROM AUTHOR]

Objective Transpetrosal approaches for the treatment of petroclival meningiomas are often associated with substantial morbidity and long recovery. With the goal of early clinical improvement, we have used less invasive surgical approaches for petroclival meningiomas. Methods We retrospectively reviewed 32 patients with petroclival meningiomas. Eleven patients (34.4%) were managed with lateral approaches (retrosigmoid or far lateral approach), 17 (53.1%) with anterior midline approaches (endoscopic endonasal approach [EEA]), and 4 (12.5%) with a combination. Results The average Karnofsky Performance Score (KPS) at presentation was 73.8. The average postoperative KPS improved to 87.9 ( P < 0.001) during short-term follow-up of 14 months (range, 1–42) and was significantly higher in primary tumors ( P = 0.013), tumors <4 cm ( P = 0.039), and tumors without vascular encasement ( P = 0.002) but remained significant regardless of age, tumor size, or vascular encasement. The greatest benefit occurred with primary tumors, in young patients and in those who underwent nontotal resection ( P < 0.001). EEA had a significantly greater potential for improved KPS ( P = 0.002). Gross ( n = 6) or near total ( n = 9) resection was achieved in 15 of 32 cases (47%). Complications included new cranial nerve palsies affecting mainly the abducens nerve (18.7%). New lower cranial nerve palsies occurred in only 1 case (3.1%). Other complications included postoperative hydrocephalus (15.6%) and cerebrospinal fluid leak (28.1%). One patient died in the perioperative period (3.1%). Conclusions In the short-term, less aggressive cranial base approaches, including retrosigmoid exposures and the recently introduced EEA, are effective alternatives to transpetrosal approaches for debulking petroclival meningiomas with significant early clinical improvement and limited major surgical complications. [ABSTRACT FROM AUTHOR]

The article pays tribute to U.S. neurosurgeon and professor Albert L. Rhoton Jr.

Introduction Complete or partial removal of the pterygoid process provides lateral extension of the endonasal corridor necessary to approach the Meckel cave, infrapetrous skull base, and medial infratemporal fossa. This paper provides the anatomical foundations for the endoscopic endonasal transpterygoid approachwith preservation of all neurovascular structures inside the pterygopalatine fossa. Methods Eight endoscopic transpterygoid approaches were performed in fresh cadaveric specimens. In all dissections the vidian nerve and the periosteal sac enclosing the pterygopalatine fossa were preserved. Results We reliably transposed the pterygopalatine fossa to approach the Meckel cave, infrapetrous skull base, and medial infratemporal region, preserving the neurovascular structures inside the pterygopalatine fossa in all specimens. Conclusions The transposition of the pterygopalatine fossa neurovascular structures for endoscopic endonasal approaches to the skull base is an alternative technique that is both feasible and desirable. The transposition requires no additional technical skills but requires comprehensive knowledge of its anatomy. The anatomical preservation of the neurovascular structures is potentially beneficial to the quality of life of patients. Clinical studies are necessary to prove the real benefits of this technique. [ABSTRACT FROM AUTHOR]

Introduction Surgical resection of lesions occupying the incisural space is challenging. In a comparative fashion, we aimed to describe the anatomy and surgical approaches to the tentorial incisura and to the rostral brainstem via the intradural subtemporal approach and its infratentorial extensions. Methods Six fresh human head specimens (12 sides) were prepared for the microscopic dissection of the tentorial incisura using the intradural subtemporal approach and its infratentorial extensions. Endoscope was used to examine the anatomy of the region inadequately exposed with the microscope. Image-guided navigation was used to confirm bony structures visualized around the petrous apex. Results Standard subtemporal approach provides surgical access to the supratentorial brainstem above the pontomesencephalic sulcus and to the lateral surface of the cerebral peduncle. The linear or triangular tentorial divisions can provide access to the infratentorial space below the pontomesencephalic sulcus. The triangular tentorial flap in comparison with the linear incision obstructs the exposure of anterior incisural space and of the prepontine cistern. Visualization of the brainstem below the trigeminal nerve can be achieved by the anterior petrosectomy. Conclusion Infratentorial extension of the intradural subtemporal approach is technically demanding due to critical neurovascular structures and a relatively narrow corridor. In-depth anatomical knowledge is essential for the selection of the appropriate operative approach and safe surgical resections of lesions. [ABSTRACT FROM AUTHOR]

We report a technical variation of the endoscopic endonasal approach to the sellar and suprasellar regions which relies on the use of a 45-degree angled endoscope. The so-called "'infrasellar approach" aims at excising lesions situated within the intermediate and posterior lobes of the pituitary gland without damaging the anterior lobe, thus potentially minimizing endocrinological morbidity. In this regard the endoscopic infrasellar approach might be advantageous in selected cases when compared with the traditional transsphenoidal approach with the microscope. We describe the technique and illustrate it with representative clinical cases. [ABSTRACT FROM AUTHOR]

Background Sinonasal debridement is typically performed in the weeks following endonasal skull base surgery (ESBS). In the pediatric population, this second-look procedure may require general anesthesia; however, there is currently little evidence assessing the benefit of this practice. Methods This was a multicenter retrospective study of pediatric patients (age <18 years) undergoing a planned second-look debridement under general anesthesia following ESBS. Intraoperative findings, interventions performed, and perioperative complications were reviewed. Multivariate regression analysis was performed to identify associations between intraoperative findings and clinical factors. Results We reviewed 69 cases of second-look debridements (age mean 8.6 ± 4.2 years, range: 2–18 years), occurring a mean of 18.3 ± 10.3 days following ESBS. All abnormal findings were noted in patients age ≤12 years. Synechiae were noted in 8.7% of cases, bacterial rhinosinusitis in 2.9%, and failed reconstruction with cerebrospinal fluid leak in 4.5% (two cases of flap malposition and one case of flap necrosis). All failed reconstructions were noted following expanded endonasal cases for craniopharyngioma, and in each case, a revision reconstruction was performed during the second-look surgery. Synechiae were not significantly associated with younger age, revision cases, or cases with reconstructive flaps. There were no perioperative complications. Conclusion Second-look debridement under general anesthesia may be useful in the identification and intervention of sinonasal pathology following endoscopic skull base surgery, particularly in children ≤12 years old or those with pedicled flap reconstructions. Larger controlled studies are warranted to validate this practice and refine indications and timing of this second procedure. [ABSTRACT FROM AUTHOR]

Key Points: ETD symptoms are present in 16% patients with underlying skull base pathology.Preoperative ETD symptoms improve following surgical treatment of skull base pathology.ETD symptoms may worsen in patients with central, posterior, or malignant skull base pathology. [ABSTRACT FROM AUTHOR]

This article, titled "Cavernous Sinus Exenteration for Invasive Mucormycosis," discusses a case study of a 61-year-old woman with HIV and diabetes mellitus who experienced vision loss due to invasive rhino-orbito-cerebral mucormycosis. Despite initial surgery and antifungal therapy, the disease progressed into the cavernous sinus and trigeminal nerve branches. The authors performed a STA-to-MCA bypass and a middle fossa approach for cavernous sinus exenteration, which successfully controlled the disease. The article highlights the technical aspects of cavernous sinus exenteration. [Extracted from the article]

This article, published in the Journal of Neurological Surgery, discusses a case presentation of a 2-year-old boy with a tubero-infundibular craniopharyngioma. The boy had a history of previous surgeries and developed visual abnormalities due to the growth of the tumor. The authors used an endoscopic endonasal transplanum approach to completely remove the tumor, resulting in improvement of visual symptoms. However, the patient did develop diabetes insipidus postoperatively. The article provides valuable insights into the treatment of pediatric patients with craniopharyngioma. [Extracted from the article]

This article discusses the surgical anatomy of the transmastoid transcervical intradural approach to the jugular foramen, which is a challenging area for skull base surgeons due to the presence of critical structures. The approach is versatile and allows for modifications to tailor it to specific tumors. The article provides a detailed description of the surgical steps and relevant anatomy, including variations such as vertebral artery transposition and facial nerve rerouting. The transmastoid transcervical intradural approach provides excellent exposure to the jugular foramen and surrounding areas, but precise knowledge of the anatomy is crucial due to the complex relationships of vital structures in this region. [Extracted from the article]

This article, published in the Journal of Neurological Surgery, explores the pterygoid-sphenoidal fissure (PSF) as a key landmark for accessing the foramen lacerum in pediatric endoscopic endonasal surgery. The study evaluates the morphometry and developmental variations of the PSF in a general pediatric population using computed tomography scans. The results show that the length, width, and morphology of the PSF vary significantly across different age groups. Understanding these radiological findings is important for preoperative planning and intraoperative guidance in pediatric endoscopic endonasal surgery. [Extracted from the article]

This article discusses seven different techniques for pituitary transposition in endoscopic endonasal surgery. The techniques are categorized based on their relationship with the dura mater and include extradural, hybrid extradural/intradural, interdural transcavernous, extended interdural transcavernous, intradural hemitransposition, intradural, and pituitary sacrifice. The article evaluates the clinical application and selection of these techniques in different anatomical regions and types of pathology. The authors emphasize the importance of selecting the most appropriate technique based on the specific case and preoperative pituitary function for successful surgical outcomes. [Extracted from the article]

This article discusses the surgical technique of endoscopic endonasal pituitary sacrifice (EE-PS) for selected complex tumors with retrochiasmatic and retroclival extension. The study describes the relevant surgical anatomy and step-by-step operative technique of EE-PS. The authors also report their clinical experience with 13 patients who underwent EE-PS, including their indications, outcomes, and complications. The article concludes that EE-PS is a feasible surgical option to improve visibility and accessibility to the retroclival and retrochiasmatic space, thus increasing tumor resectability. [Extracted from the article]

This article discusses the issue of unplanned hospital readmissions following trans-sphenoidal surgery for Cushing's disease. The study analyzed data from a multi-institutional database of patients who underwent this surgery between 2003 and 2023. The results showed that 10.3% of patients experienced unplanned readmissions, with the most common reasons being hyponatremia, CSF leak evaluation, headache/nausea, and epistaxis. The study also found that an increased number of chronic medical conditions and the need for a return to surgery were associated with a higher chance of unplanned readmission. The authors suggest strategies to mitigate these readmissions, such as fluid restriction and optimizing chronic medical conditions. [Extracted from the article]

This article discusses the outcomes of endoscopic endonasal transcavernous surgery for pituitary adenomas. The study analyzed data from patients who underwent this surgery between 2018 and 2023. The results showed that transcavernous surgery was more common in repeat surgery patients and those with functioning adenomas. The study also examined the invasion patterns of the cavernous sinus compartments and found that the medial wall was the most frequently involved. The authors concluded that the outcomes of transcavernous surgery can vary depending on the specific compartments involved. [Extracted from the article]

This article, published in the Journal of Neurological Surgery, explores the microsurgical anatomy of the "true" petrous apex and the feasibility of accessing it through the endoscopic endonasal approach. The study conducted detailed dissections of post-mortem human specimens and identified key anatomical landmarks and neurovascular structures. The authors found that the endoscopic endonasal petrosectomy approach provides access to the "true" petrous apex, with two variants based on its relationship with the internal carotid artery. The study concludes that this approach is an effective surgical alternative for accessing lesions in this region. [Extracted from the article]

This article, published in the Journal of Neurological Surgery, examines the use of indocyanine green (ICG) fluorescence angiography to evaluate the impact of surgical and patient factors on the vascular perfusion of nasoseptal flaps (NSFs) in endoscopic skull base surgery (ESBS). The study found that tobacco smokers had lower baseline fluorescence intensity compared to nonsmokers, and patients who underwent a transpterygoid approach had a greater decrease in fluorescence intensity following reconstruction. Other factors, such as revision case, timing of flap harvest, and concurrent septoplasty, did not significantly influence fluorescence intensity. The article concludes that tobacco use and transpterygoid approaches may be associated with decreased vascular perfusion of NSFs. [Extracted from the article]

The article discusses the extreme lateral supracerebellar infratentorial and transtentorial (ELSIT) approach for accessing lesions in the ambient cistern, a challenging area due to its deep location and vital neurovascular structures. The study conducted a systematic dissection on post-mortem human specimens to investigate the anatomical landmarks and measurements of this approach. The ELSIT approach provides a narrow corridor leading to the ambient cistern, with specific landmarks such as the superior petrous vein and posterior root of the trigeminal nerve. Understanding these anatomical nuances is crucial for optimizing surgical outcomes and minimizing complications. [Extracted from the article]

Objectives Pituitary tumor treatment is hampered by the relative rarity of the disease, absence of a multicenter collaborative platform, and limited translational–clinical research partnerships. Prior studies offer limited insight into the formation of a multicenter consortium. Design The authors describe the establishment of a multicenter research initiative, Registry of Adenomas of the Pituitary and Related Disorders (RAPID), to encourage quality improvement and research, promote scholarship, and apply innovative solutions in outcomes research. Methods The challenges encountered during the formation of other research registries were reviewed with those lessons applied to the development of RAPID. Setting/Participants RAPID was formed by 11 academic U.S. pituitary centers. Results A Steering Committee, bylaws, data coordination center, and leadership team have been established. Clinical modules with standardized data fields for nonfunctioning adenoma, prolactinoma, acromegaly, Cushing's disease, craniopharyngioma, and Rathke's cleft cyst were created using a Health Insurance Portability and Accountability Act-compliant cloud-based platform. Currently, RAPID has received institutional review board approval at all centers, compiled retrospective data and agreements from most centers, and begun prospective data collection at one site. Existing institutional databases are being mapped to one central repository. Conclusion The RAPID consortium has laid the foundation for a multicenter collaboration to facilitate pituitary tumor and surgical research. We sought to share our experiences so that other groups also contemplating this approach may benefit. Future studies may include outcomes benchmarking, clinically annotated biobank tissue, multicenter outcomes studies, prospective intervention studies, translational research, and health economics studies focused on value-based care questions. [ABSTRACT FROM AUTHOR]

Background: The Cavernous Hemangioma Exclusively Endonasal Resection (CHEER) staging system has become the gold standard for outcomes reporting in endoscopic orbital surgery for orbital cavernous hemangiomas (OCHs). A recent systematic review demonstrated similar outcomes between OCHs and other primary benign orbital tumors (PBOTs). Therefore, we hypothesized that a simplified and more comprehensive classification system could be developed to predict surgical outcomes of other PBOTs. Methods: Patient and tumor characteristics as well as surgical outcomes from 11 international centers were recorded. All tumors were retrospectively assigned an Orbital Resection by Intranasal Technique (ORBIT) class and stratified based on surgical approach as either exclusively endoscopic or combined (endoscopic and open). Outcomes based on approach were compared using chi‐squared or Fisher's exact tests. The Cochrane‐Armitage test for trend was used to analyze outcomes by class. Results: Findings from 110 PBOTs from 110 patients (age 49.0 ± 15.0 years, 51.9% female) were included in the analysis. Higher ORBIT class was associated with a lower likelihood of gross total resection (GTR). GTR was more likely to be achieved when an exclusively endoscopic approach was utilized (p < 0.05). Tumors resected using a combined approach tended to be larger, to present with diplopia, and to have an immediate postoperative cranial nerve palsy (p < 0.05). Conclusion: Endoscopic treatment of PBOTs is an effective approach, with favorable short‐term and long‐term postoperative outcomes as well as low rate of adverse events. The ORBIT classification system is an anatomic‐based framework that effectively facilitates high‐quality outcomes reporting for all PBOTs. [ABSTRACT FROM AUTHOR]

A comprehensive map of the structural connectome in the human brain has been a coveted resource for understanding macroscopic brain networks. Here we report an expert-vetted, population-averaged atlas of the structural connectome derived from diffusion MRI data (N = 842). This was achieved by creating a high-resolution template of diffusion patterns averaged across individual subjects and using tractography to generate 550,000 trajectories of representative white matter fascicles annotated by 80 anatomical labels. The trajectories were subsequently clustered and labeled by a team of experienced neuroanatomists in order to conform to prior neuroanatomical knowledge. A multi-level network topology was then described using whole-brain connectograms, with subdivisions of the association pathways showing small-worldness in intra-hemisphere connections, projection pathways showing hub structures at thalamus, putamen, and brainstem, and commissural pathways showing bridges connecting cerebral hemispheres to provide global efficiency. This atlas of the structural connectome provides representative organization of human brain white matter, complementary to traditional histologically-derived and voxel-based white matter atlases, allowing for better modeling and simulation of brain connectivity for future connectome studies. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented in response to the article "Microscopic and endoscopic pituitary surgery," published in the previous issue of the journal.

No abstract available [ABSTRACT FROM AUTHOR]

To identify factors associated with successful use of free tissue grafting versus vascularized reconstruction after resection of pituitary tumors. A retrospective chart review of 2 tertiary academic medical centers over 3.5 years was conducted. Variables assessed included age, sex, body mass index, pathology, extent of surgical exposure, cavernous sinus or suprasellar extension, intraoperative cerebrospinal fluid (CSF) leak, grade of leak, previous radiation, and previous surgery. Reconstructive techniques were divided into no reconstruction, free tissue grafts, and vascularized flaps. A total of 485 patients were included. Free grafts were used in 299/485 cases (61.6%) and were more commonly used with smaller approaches (P < 0.001). Larger exposure size and CSF leak grades 2 and 3 were associated with vascularized flap use (P < 0.001 and P = 0.012, respectively). Using multivariate regression, type of reconstruction could be predicted by increasing extent of approach, intraoperative CSF leak grade, and suprasellar extension (odds ratio [OR], 2.014, P < 0.001, 95% confidence interval [CI], 1.335–3.039; OR, 1.636, P = 0.025, 95% CI, 1.064–2.517; OR, 1.975, P < 0.001, 95% CI, 1.554–2.510, respectively). Postoperative CSF leak occurred in 9 of 173 patients (5.2%) with intraoperative leak and was not associated with any factors on analysis. We propose an algorithm whereby grade 1 CSF leaks in sellar and parasellar resections can be successfully reconstructed with a free graft. Vascularized flaps may be reserved for grade 2 or 3 intraoperative CSF leaks, extended approaches, or tumors with suprasellar extension. [ABSTRACT FROM AUTHOR]

Background Cavernous sinus (CS) tumors often are considered inoperable. We present our experience with endoscopic endonasal surgery (EES) and compare the outcomes for different tumor. Methods EES (medial or lateral approach) was used in 234 patients with CS tumors. The cohort included 175 (75%) pituitary adenomas and 59 (25%) nonadenomatous lesions. Results Presenting symptoms were significantly different between the 2 groups, with cranial neuropathies occurring mainly in nonadenomas ( P < 0.0001). The overall gross total tumor resection rate from the CS was 37.3% (37.1% in adenomas, 38.1% in non-adenomas). In total, preexisting cranial nerve (CN) dysfunction improved in 56.4% of the patients. After treatment completion (including radiation of residual tumor), 83.3% of acromegalic patients, 50% of prolactinomas and 33.3% of Cushing's disease, were in remission. Visual loss improved in 86.8% of adenomas and in 70.8% of nonadenomas. Intracavernous CN palsies improved in 77.3% of adenomas and 42.4% of nonadenomas. New permanent CN palsies occurred in 7 nonadenomas, which is significantly greater than in adenomas ( P = 0.007). The leak rate of cerebrospinal fluid was 6.3% for adenomas and 11.9% for nonadenomas. Four patients suffered an internal carotid artery injury with no neurologic sequelae in 3 cases and 1 death (0.4%). Conclusions EES provides an easily accessible midline corridor to the CS with equivalent or superior results to transcranial approaches in the management of select tumors. Symptomatology due to CS invasion is more likely to improve in pituitary adenomas and the rate of surgical complications is greater in nonadenomas. Using a team approach, the overall mortality due to vascular injury is low. [ABSTRACT FROM AUTHOR]