Applied anatomical study of clipping bilateral intracranial aneurysms via unilateral pterional keyhole approach

Objective To explore the basic and clinical anatomy of unilateral pterional keyhole approach for clipping bilateral intracranial aneurysms.

Methods 30 sides of 15 cadavers of skull specimens (pterional keyhole approach, PTK) was simulated for craniotomy. The main intracranial vessels, including distal carotid artery (DICA), anterior cerebral artery (ACA), middle cerebral artery (MCA), and ophthalmic segment of internal carotid artery (OICA) were observed under microscope. The maximum lengths that can be observed were measured to provide anatomical data for clinical purposes. To further apply it to clinical practice, a modified Salma surgical exposure scale was introduced to quantify the score.

Results The contralateral A1 segment, proximal A2 segment, M1 segment, DICA, and OICA could be exposed through PTK; the contralateral A2 segment (lateral), M1 segment (posterior), M2 segment, MCAB (inferior), DICA (posterior and lateral), and OICA (superior, inferior, and lateral) could not be fully exposed to perform simulated surgical clipping (operability rate less than 75%).

Conclusion Contralateral aneurysms of A1 segment, A2 segment (anterior, posterior, and medial), M1 segment (anterior, superior, and inferior), MCAB (superior and lateral), ICAB, DICA (anterior and medial), and OICA (medial) could be fully exposed from different angles, and could be performed with surgical maneuvers via supraorbital eyebrow keyhole approach.