Predictor of Visual Impairment Following Paraclinoid Aneurysm Surgery: Special Consideration of Surgical Microanatomy Related to Paraclinoid Structures

Abstract

BACKGROUND Microsurgical clipping with extradural anterior clinoidectomy (EDAC) for paraclinoid aneurysm is an established technique with good angiographic outcomes, although postoperative worsening of visual acuity remains a concern. Multiple reports show visual acuity deteriorating after clipping, yet the cause remains unclear. OBJECTIVE To analyze results of asymptomatic paraclinoid aneurysm surgeries treated with EDACs, specifically focusing on the microanatomy of paraclinoid structure dissection. This determined the causes of delayed visual impairment and microsurgical indications. METHODS Results of the treatment with EDAC of 94 patients with cerebral aneurysm and normal preoperative visual acuity but also full visual fields were retrospectively analyzed. RESULTS The mean aneurysm size was 6.2 (±3.3) mm. Clipping was performed in 87 cases and trapping in 7 cases. Complete angiographic occlusion was observed in 91 patients. In 26 cases, a postoperative visual deficit occurred. A total of 20 cases exhibited partial visual field deficits, including 5 who were asymptomatic. Visual deficits were only detectable by postoperative ophthalmologic testing. Six showed light perception impairment or blinding. Of the 15 patients with symptomatic partial visual field deficits, 5 showed improvement at follow-up. Visual deficits persisted in 22 patients at the last follow-up. Multivariate logistic regression analysis revealed that medial projecting aneurysm (adjusted odds ratio [OR]: 10.43) and the opening of the carotidoculomotor membrane (adjusted OR: 5.19) were significantly related to visual impairment. CONCLUSION Excess dissection of carotidoculomotor membranes causes postoperative delayed visual worsening. For treating small, asymptomatic paraclinoid aneurysms, carotidoculomotor membranes should not be opened, and microsurgical clipping should not be performed for preoperative asymptomatic medial projecting aneurysms.

Visual Evoked Potential Can Predict Deterioration of Visual Function After Direct Clipping of Paraclinoid Aneurysm With Anterior Clinoidectomy

“…The rates of Final VAL and Final VFL were 12% and 28%, respectively (Table 2). As compared with previous reports, 12,[28][29][30][31] the rate in our study was relatively higher. This is probably because postoperative visual impairment in our study included moderate impairment assessed by ophthalmologists or because we continued operation unless the wave of VEP completely disappeared.…”

“…No patient showed postoperative light perception or mononuclear blindness, whereas it was observed in 3.6%, 16 4.3%, 28 and 6.3% 31 of the patients in other studies (Table 2). We indicated the direct clipping only to Al-Rodhan group Ia, group Ib, and group II aneurysms.…”

Endoscopic transorbital extradural anterior clinoidectomy: A stepwise surgical technique and case series study [SevEN-013]

“…The step involving identification and unroofing of the optic canal is key to safe and successful anterior clinoidectomy in the ETOA. This allows early decompression of the optic nerve during surgery, which can minimize the possible damage to the optic nerve during the subsequent steps ( 22 , 38 , 56 , 57 ). The optic canal could be readily confirmed from below after detaching the periorbita from the orbital roof, while the grove whit the optic canal can be detected using a blunt hook dissector.…”

Paraclinoid aneurysms clipping through an extradural sphenoid ridge keyhole approach

“…Hemostatic agents could be used to avoid oozing from the CS [ 5 ]; however, they should not be applied excessively since this could be associated with cranial nerve dysfunction [ 4 ]. Minimal drilling technique using gubias, Kerrison forceps, and opening the carotid-oculomotor membrane and ON dura prevent visual impairment [ 3 , 4 , 7 , 9 ].…”

“…Since a short incision is used and minimal dissection of the temporal muscle is done, the cosmetic results and surgical time are better than the standard pterional approach [ 6 ]. Second, monocular blindness could be observed in 5.2% of the cases and could appear 12–72 h postoperatively [ 4 , 9 ]. In this sense, avoiding excessive use of drill near the ON and protecting the clip’s head with a hemostatic sponge around the ON is advisable.…”