CTA-based planning for clipping of paraclinoid aneurysms: TS-ACP validation and selective contralateral interoptic outcomes.

OBJECTIVE

To validate CTA-based tuberculum sellae-anterior clinoid process (TS-ACP) classification against operative distal dural ring (DDR) assessment and evaluate prespecified interoptic geometry for selective contralateral interoptic clipping.

METHODS

This registry cohort included 105 adults undergoing microsurgical clipping of paraclinoid internal carotid artery aneurysms during 2011-2024. Two blinded reviewers retrospectively applied TS-ACP classification and interoptic criteria to preoperative CTA; DSA provided complementary anatomical characterization. The principal clinical safety endpoint was permanent visual worsening at 12 months. Between-approach analyses were exploratory because corridor selection was nonrandomized and anatomy-driven.

RESULTS

Seventy-five patients underwent ipsilateral and 30 contralateral interoptic clipping. TS-ACP classification matched operative DDR assessment in 95/105 aneurysms (90.5%; κ = 0.76). For identifying the operative intradural category, sensitivity was 100%, specificity 70.0%, and negative predictive value 100%. Favorable geometry was more frequent with contralateral selection (76.7% vs 32.0%; p < 0.001; OR 6.98, 95% CI 2.63-18.52) and remained associated after excluding multiple-aneurysm operations (OR 13.93, 95% CI 2.88-67.37). Permanent visual worsening occurred in 7/75 ipsilateral and 1/30 contralateral cases (p = 0.43); the study was underpowered for comparative safety inference. CTA/DSA-confirmed complete occlusion was achieved in 79/85 patients (92.9%).

CONCLUSIONS

TS-ACP classification provided a high-sensitivity CTA-based estimate of the operative intradural category, and prespecified geometry was strongly associated with contralateral corridor selection. No excess permanent visual morbidity was observed in carefully selected contralateral cases, but sparse events, anatomical differences, and nonrandomized selection preclude robust comparative safety conclusions.