Olfactory dysfunction in patients undergoing supraorbital keyhole craniotomy for clipping of unruptured aneurysms

Abstract

Olfactory performance has rarely been assessed in the perioperative phase ofelective aneurysm surgery. Here, we assessed the risk for olfactory deteriorationfollowing surgical treatment of unruptured cerebral aneurysm via the supraorbitalkeyhole craniotomy. A retrospective review of patients with electively treatedcerebral aneurysms who underwent perioperative assessment of olfactory func-tion using a sniffin’sticks odor identification test between January 2015 andJanuary 2016 was performed. A subgroup of patients without history of subarach-noid hemorrhage, without prior aneurysm treatment, and confirmed olfactoryfunction underwent supraorbital keyhole craniotomy for aneurysm clipping.Microscopic and endoscopic videos were reviewed for this subgroup. Sixty-fourpatients who underwent elective aneurysm treatment either via surgical clippingor endovascular aneurysm obliteration were identified. Prior to treatment, 4/64(6.3%) demonstrated bilateral anosmia. Collectively, 14 patients (21.9%) metsubgroup criteria of supraorbital keyhole craniotomy for aneurysm clipping. Here,olfactory performance significantly decreased postoperatively on the side of cra-niotomy (ipsilateral,P= 0.007), whereas contralateral and bilateral olfactoryfunction remained unaltered (P= 0.301 andP= 0.582, respectively). Conse-quently, 4/14 patients (28.6%) demonstrated ipsilateral anosmia 3 months aftersurgery. One patient (1/14, 7.1%) also experienced contralateral anosmiaresulting in bilateral anosmia. Intraoperative visualization of the olfactory tractand surgical maneuvers do not facilitate prediction of olfactory outcome. Thesupraorbital keyhole craniotomy harbors a specific risk for unilateral olfactorydeterioration. Lack of perioperative olfactory assessment likely results in under-estimation of the risk for olfactory decline. Despite uneventful surgery, predictionof postoperative olfactory function and dysfunction remain challenging. Clin.Anat. 33:316–323, 2020.