2026 Proffered Presentations
S022: EFFECT OF INTERNAL CAROTID ARTERY MORPHOLOGY ON PATTERNS OF CAVERNOUS SINUS INVASION AND SURGICAL OUTCOMES IN 137 PITUITARY ADENOMAS
Taishi Nakase, MS; Yuanzhi Xu, MD; Felipe Constanzo, MD; Jonathan Lamano, MD, PhD; Ana Sofia Alvarez, MD; Lily Kim, MD; Vera Vigo, MD; Juan C Fernandez-Miranda, MD; Stanford University
Introduction: With high-resolution endoscopes and refined characterization of the endonasal cavernous sinus (CS) anatomy, transcavernous surgery for pituitary adenoma resection is becoming more common at pituitary centers of excellence. However, while the effect of cavernous internal carotid artery (ICA) morphology on endovascular procedures has been thoroughly studied, its relevance to endoscopic endonasal transcavernous surgery is less well characterized. We examined the influence of cavernous ICA morphology on the pattern of CS invasion and surgical outcomes for pituitary adenomas.
Methods: We retrospectively reviewed medical records of 137 consecutive patients (65 males, median 49 years) who underwent endoscopic endonasal surgery for resection of pituitary adenomas with CS compartment invasion. CS invasion was unilateral in 120 patients and bilateral in 17 patients (154 sides). Cavernous ICA was classified into three subtypes defined by the angle between the short vertical and horizontal segments measured on preoperative CTA in the sagittal plane (Figure 1): type I (<80°), type II (between 80° and 100°), type III (>100°)
Results: Of the 154 cavernous sinuses, 63 (41%) had Type III ICA morphology, followed by 56 (36%) with Type I and 35 (23%) with Type II. The posterior compartment was more commonly invaded with Type III carotids (81%) compared to those with either Type I (62%, P=0.025) or Type II (63%, P=0.049) morphologies (Figure 2). Similar results were observed for the superior compartment, with the highest likelihood of invasion with Type III (79%) followed by Type II (69%) and Type I (59%). Notably, concurrent invasion of the superior and posterior compartments was significantly more common for Type III carotids (65%) compared to Type I or II carotids (43%, P=0.007). In contrast, tumor was significantly less likely to be identified in the inferior compartment with Type III carotids (48%) compared to Type I (68%, P=0.026) and Type II (71%, P=0.023) morphologies. While abducens nerve palsy was overall uncommon (7%) and transient in all cases, Type III carotids (13%) were linked to a significantly higher risk compared to Type I carotids (2%, P=0.035). There were no cases of ICA injury. Type II carotids (57%) were associated with a marginally lower likelihood of gross total resection compared to Type I (73%, P=0.11) and Type III (73%, P=0.11) carotids, although these differences did not achieve statistical significance. Results were similar but attenuated for biochemical remission among the functional adenomas (Type I: 67%, Type II: 53%, Type III: 62%).
Conclusion: Our study showed that ICA morphology can influence the pattern of CS invasion and pose unique surgical challenges that adversely contribute to cranial nerve injury or limit resection. These findings highlight the potential relevance of ICA morphology to decisions about the optimal approach to efficiently and safely resect pituitary adenomas within the CS.
Figure 1: Variation in cavernous ICA morphology. (A, D) Type I: < 80°. (B, E) Type II: between 80° and 100°. (C, F) Type III: > 100°.
Figure 2: Pattern of CS compartment invasion stratified by ICA morphology.
