Purpose: Aim of the study was to evaluate microsurgical treatment of complex paraclinoid aneurysms with the guidance of the newly developed intraoperative infrared 800 (I800) angiography.
Method: Out of 70 patients with paraclinoid aneurysms admitted to our department of neurosurgery from 2000 to 2006, we analyzed 10 consecutive cases with complex paraclinoid aneurysms, that is, large or giant size, broad neck, involvement of ophthalmic artery, calcifications, atherosclerotic plaques, or aneurysm thrombosis. Aneurysms were clipped via pterional craniotomy with extracranial control of the dissected internal carotid artery. All patients were submitted to both microscope-based intraoperative I800 angiography and postoperative 3D-rotational digital subtraction angiography. Findings regarding aneurysm remnants, parent or distal vessel occlusion, or stenosis were compared. Outcome was assessed according to the modified Rankin scale at 6 months.
Result: Three patients presented with SAH (Hunt and Hess grade 4 to 5), 4 patients had symptomatic aneurysms with cranial nerve dysfunction, and 3 had incidental lesions. Three aneurysms were of medium (< 1 cm), 5 of large (> 1.5 and < 2.5 cm), and 2 of giant (> 2.5 cm) size. Total aneurysm occlusion was achieved in 80% of the cases with excellent or good outcomes in 70% of the cases. One patient (H and H 4) died. Intraoperative I800 angiography analysis lasted only 2 min in all cases. The microsurgical strategy was changed in 1 (10%) of the cases (residual filling) according to the results of the intraoprative infrared 800 angiography. Patency of the ophthalmic artery could be assessed in all cases. Thrombosis, calcifications, and plaques compromised visualization. Results of intraoperative angiography were consistent with postoperative angiography in 80% of the cases. One case of a 4-mm aneurysm remnant was missed by I800 and 1 case of a mild, hemodynamically not relevant stenosis of the ICA was missed, too. We observed no side effects of the infrared dye. No patient underwent a second procedure due to the results of postoperative angiography.
Conclusion: Intraoperative I800 angiography proved to be a simple, fast, and accurate method for analyzing patency of ophthalmic artery and distal vessels in this setting. However, due to the limited visualization of aneurysms in this location, 1 case of a 4-mm remnant was missed by I800. The results of intraoperative I800 angiography directly changed the operative strategy in 10% of cases. We conclude that I800 angiography is a valuable adjunct in cases of microsurgical clipping of a complex paraclinoid aneurysm with limitations concerning the detection of aneurysm remnants. Especially in paraclinoid aneurysms, I800 may not alleviate the need for additional visualization as provided by digital subtraction angiography.
