Beyond the clip: unveiling residual aneurysms with CT angiography post-surgical clipping

Abstract Objective To evaluate the detection rate of residual aneurysms using computed tomography angiography (CTA) after microsurgical clipping and to assess the role of aneurysm morphology, including neck size and aspect ratio, in predicting incomplete occlusion. Materials and methods This single-arm quasi-experimental study was conducted at a tertiary care neurosurgical center from December 2024 to June 2025. Seventy-four patients who underwent surgical clipping for anterior circulation intracranial aneurysms were prospectively enrolled. Postoperative CTA was performed within one week of surgery using a 128-slice multidetector CT scanner. Data collected included demographic details, aneurysm location, neck size, aspect ratio, and Raymond-Roy classification. The primary outcome was the presence of residual aneurysm on CTA. Statistical analysis was performed using IBM SPSS Statistics version 26.0. Results The sample population comprised 74 patients with mean age 47.3 ± 11.1 years and 35 males (47.3%). The most common aneurysm location was anterior communicating artery (48.6%, n = 36), followed by middle cerebral artery (33.8%, n = 25). Residual aneurysms were detected in 8 patients (10.8%) on postoperative CTA, all classified as Raymond-Roy Class III. Residuals occurred in 0/21 (0%) patients with neck size < 3 mm, 2/24 (8.3%) with neck size 3–5 mm, and 6/29 (20.7%) with neck size > 5 mm. The association between neck size and residual aneurysms was statistically significant (χ² = 7.85, p = 0.020). Similarly, residuals were found in 1/36 (2.8%) patients with aspect ratio < 1.5 versus 7/38 (18.4%) with aspect ratio ≥ 1.5, demonstrating significant association (χ² = 4.84, p = 0.028). Conclusion CTA reliably detected residual aneurysms in 10.8% of patients following microsurgical clipping. Wide-neck aneurysms (> 5 mm) and those with high aspect ratios (≥ 1.5) demonstrated significantly increased risk of incomplete occlusion. Routine postoperative CTA should be considered for morphologically complex aneurysms to guide early reintervention and improve patient safety.