Contralateral interoptic approach to paraclinoid aneurysms: a patient-selection algorithm based on anatomical...

Area of Science:

• Neurosurgery
• Vascular Surgery
• Anatomy

Background:

• Medial paraclinoid internal carotid artery (ICA) aneurysms present significant surgical challenges.
• The contralateral interoptic trajectory offers potential access to the medial ICA surface.

Purpose of the Study:

• To quantitatively measure the medial ICA area accessible via the interoptic triangle.
• To develop a patient-selection algorithm for this surgical approach based on preoperative imaging.

Main Methods:

• Cadaveric dissection of 10 sides to define the accessible medial paraclinoid ICA.
• Measurement of accessible distances and angles relative to the distal dural ring (DDR).
• Validation of measurements in 8 clinical cases using preoperative and intraoperative data.

Main Results:

• In the sagittal plane, the accessible area extended 2.5–8.4 mm distal to the DDR.
• In the coronal plane, the accessible area ranged from 21.7° to 130.9° relative to the vertical midline.
• The proposed algorithm showed 75% consistency in clinical cases.

Conclusions:

• The contralateral interoptic approach is a viable option for medial paraclinoid ICA aneurysms.
• Safe aneurysm clipping is feasible if the neck is within 2.5–8.4 mm distal to the DDR and 21.7°–130.9° medially on the coronal plane.