Abstract
Objective: Although flow-diverter stents have emerged as a mainstay in the management of parasellar aneurysms, certain cases, particularly small aneurysms (<5 mm) or those causing visual disturbances remain best addressed by direct microsurgical clipping. This study aimed to demonstrate a practical and safe technique for extradural anterior clinoidectomy and circumferential distal dural ring (DDR) opening using the Dolenc’s approach, which facilitates effective clipping with minimal neurovascular manipulation.
Methods: Two cases of unruptured parasellar aneurysms were treated with microsurgical clipping. Case 1 involved a 45-year-old woman with a 3.8 mm superiorly projecting aneurysm at the ophthalmic segment of the left internal carotid artery (ICA), which was detected incidentally during evaluation for vertigo. Case 2 involved a 65-year-old woman with a 6.6 mm carotid cave aneurysm showing interval growth on surveillance imaging. Preoperative computed tomography angiography (CTA)-SSFP fusion imaging was used to evaluate the intradural or extradural positions of the aneurysms and their relationships with adjacent structures.
Surgical procedures were performed under high magnification using Dolenc’s approach. The dura propria was dissected up to the foramen rotundum to maximize the operative exposure. The anterior clinoid process (ACP) was drilled extradurally after unroofing the optic canal, and the optic strut was removed to expose the clinoid segment (C3) of the ICA. The clinoid venous plexus (CVP) membrane was identified and dissected longitudinally to enable a circumferential DDR incision.
Results: In Case 1, a partial DDR incision allowed preservation of the ophthalmic artery and successful neck clipping with minimal traction. In Case 2, retrograde suction and decompression (rS&D) were employed to deflate the aneurysm and facilitate circumferential DDR opening. This enabled full mobilization of the ICA and precise dissection of the carotid cave aneurysm from the dural ring, followed by complete clipping. In both cases, postoperative CTA confirmed complete aneurysm obliteration without ischemic complications. No new neurological deficits were observed, and both patients were discharged with a modified Rankin Scale score of 0.
Conclusion: Extradural anterior clinoidectomy and circumferential DDR opening significantly enhanced the safety and effectiveness of direct clipping for parasellar aneurysms. Key technical strategies include wide extradural exposure, identification of the correct membrane layer around the ICA, and strict adherence to the principle of “manipulating only the membrane, not the vessel.” These techniques are especially valuable in cases involving carotid cave aneurysms or when sufficient visualization and vascular mobilization are essential. Mastery of skull base microsurgical anatomy and careful techniques are critical for optimizing surgical outcomes.
