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Suprasellar extension, cavernous sinus invasion, and involvement of intracranial vascular structures and cranial nerves are among the challenges faced by surgeons operating on giant pituitary macroadenomas. Intraoperative tissue shifts may render neuronavigation techniques inaccurate. Intraoperative magnetic resonance imaging can solve this problem, but it may be costly and time consuming. However, intraoperative ultrasonography (IOUS) allows for quick, real-time feedback and may be particularly useful when facing giant invasive adenomas. Here, we present the first study examining technique for IOUS-guided resection specifically focusing on giant pituitary adenomas. To describe the use of a side-firing ultrasound probe in the resection of giant pituitary macroadenomas. We describe an operative technique using a side-firing ultrasound probe (Fujifilm/Hitachi) to identify the diaphragma sellae, confirm optic chiasm decompression, identify vascular structures related to tumor invasion, and maximize extent of resection in giant pituitary macroadenomas. Side-firing IOUS allows for identification of the diaphragma sellae to help prevent intraoperative cerebrospinal fluid leak and maximize extent of resection. Side-firing IOUS also aids in confirmation of decompression of the optic chiasm via identification of a patent chiasmatic cistern. Furthermore, direct identification of the cavernous and supraclinoid internal carotid arteries and arterial branches is achieved when resecting tumors with significant parasellar and suprasellar extension. We describe an operative technique in which side-firing IOUS may assist in maximizing extent of resection and protecting vital structures during surgery for giant pituitary adenomas. Use of this technology may be particularly valuable in settings in which intraoperative magnetic resonance imaging is not available. [ABSTRACT FROM AUTHOR]

Comprehensive quantitative evaluation of the intercarotid artery distance (ICD) in the pediatric population has not been sufficiently explored. This study aims to measure the minimal ICDs at multiple levels of the skull base to assess changes in the ICD during development. Measurement of the ICDs between the paired paraclival, parasellar, and paraclinoid segments of the internal carotid artery (ICA) was performed on coronal MRI from 540 patients ranging from 0 to 17 years old (n = 30 for each age). Comparison of these indices in the very young (0–5 years, Group 1) and young (6–17 years, Group 2) patients, and assessment of the degree of sphenoid sinus pneumatization was employed. The narrowest ICD was located at the paraclinoid ICAs in the vast majority of cases (89.44%). When comparing the ICDs in very young age patients with the ICDs of 17 years old subjects, a statistically significant difference was found at the paraclival (ages 0–5), parasellar (ages 0–2), and paraclinoid (ages 0–4) ICDs (p < 0.05). Comparison of the ICDs between the intergroups (Group 1 and 2) also demonstrated a statistically significant difference (p < 0.0001). Pneumatization of the sphenoid sinus was initially noted to start at 3 years of age, and there were no patients with a non-pneumatized sphenoid sinus identified after 7 years of age in our cohort. Measurement of ICDs at multiple levels provides a valuable reference for EEA procedures in the pediatric population. While the ICD may be largely stable in the pediatric population after 5 years of age, additional anatomic factors may restrict transsphenoidal access in very young patients (0–5 years). [ABSTRACT FROM AUTHOR]

Background/Objective The inframeatal area represents a challenging region for skull base surgeons. Various surgical corridors have been described to access this area and frequently are used in combination. Recent studies describe the expanded endoscopic endonasal approach (EEA) as an established route for midline regions, particularly medial to the internal carotid arteries (ICA). We sought to evaluate the accessibility, maneuverability, and freedom of movement of the expanded endoscopic endonasal approach to the inframeatal region. Methods An EEA combining a middle and an inferior transclival corridor with an infrapetrous and a supracondylar lateral expansion was performed in 5 embalmed human cadaveric heads. The area of exposure and the surgical freedom to access the inframeatal area were calculated. The angle of attack and distances from the lacerum segment of the ICA to several anatomical targets also were measured. Our database was searched to select clinical case examples. Results The EEA provided an exposure area of 101.26 ± 16.66 mm2 and an area of surgical freedom of 1208.50 ± 507.01 mm2. The angles of attack in both the sagittal and axial planes were wider at the lacerum segment of the ICA and narrower at the dural entrance zone of cranial nerves VII/VIII. Three chondrosarcomas are presented as case illustrations. Conclusions The EEA is a feasible route to the inframeatal area. This approach provides a safe working corridor for lesions in this region, as shown by the anatomical and clinical findings presented here. Comparative studies and large case series are warranted to further establish its clinical value. Highlights • EEA is surgically feasible for approaching lesions at the inframeatal area. • EEA inframeatal approach may avoid the need for ICA and eustachian tube mobilization. • Clinical application of this approach includes chordoma and cholesterol granuloma. • Paramedial lesions such as chondrosarcomas may warrant a combined strategy. [ABSTRACT FROM AUTHOR]