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

Abstract

Olfactory performance has rarely been assessed in the perioperative phase of elective aneurysm surgery. Here, we assessed the risk for olfactory deterioration following surgical treatment of unruptured cerebral aneurysm via the supraorbital keyhole craniotomy. A retrospective review of patients with electively treated cerebral aneurysms who underwent perioperative assessment of olfactory function using a sniffin' sticks odor identification test between January 2015 and January 2016 was performed. A subgroup of patients without history of subarachnoid hemorrhage, without prior aneurysm treatment, and confirmed olfactory function underwent supraorbital keyhole craniotomy for aneurysm clipping. Microscopic and endoscopic videos were reviewed for this subgroup. Sixty-four patients who underwent elective aneurysm treatment either via surgical clipping or endovascular aneurysm obliteration were identified. Prior to treatment, 4/64 (6.3%) demonstrated bilateral anosmia. Collectively, 14 patients (21.9%) met subgroup criteria of supraorbital keyhole craniotomy for aneurysm clipping. Here, olfactory performance significantly decreased postoperatively on the side of craniotomy (ipsilateral, P = 0.007), whereas contralateral and bilateral olfactory function remained unaltered (P = 0.301 and P = 0.582, respectively). Consequently, 4/14 patients (28.6%) demonstrated ipsilateral anosmia 3 months after surgery. One patient (1/14, 7.1%) also experienced contralateral anosmia resulting in bilateral anosmia. Intraoperative visualization of the olfactory tract and surgical maneuvers do not facilitate prediction of olfactory outcome. The supraorbital keyhole craniotomy harbors a specific risk for unilateral olfactory deterioration. Lack of perioperative olfactory assessment likely results in underestimation of the risk for olfactory decline. Despite uneventful surgery, prediction of postoperative olfactory function and dysfunction remain challenging. Clin. Anat. 33:316-323, 2020.

Cosmetic Outcomes of Supraorbital Keyhole Craniotomy Via Eyebrow Incision: A Systematic Review and Meta-Analysis

“…This review yielded 124 studies that were eligible, all of which were included in the qualitative and quantitative synthesis as well as risk of bias appraisal. 3 4 7 8 9 10 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83…”

Anatomy and Microsurgical Relevance of the Outer Arachnoid Envelope around the Olfactory Bulb Based on Endoscopic Cadaveric Observations

“…Interestingly in several clinical studies on a large number of cases, the percentage of postoperative olfactory dysfunction after supraorbital or frontolateral approach remains very low. 29 30 A possible anatomical background of these observations could be the independent vascular supply of the nerve. 1 A further factor could be our recent observation that during forced retraction of the frontal lobe the olfactory bulb may be significantly dislocated from the olfactory fossa but without consecutive transection of the fila olfactoria ( Fig.…”

“…This provides significantly more protection of the ipsilateral olfactory nerve during the pterional approach. Interestingly in several clinical studies on high number of cases the percentage of postoperative olfactory dysfunction after supraorbital or frontolateral approach remains very low 31,32 . A possible anatomical background of these observations could be the independent vascular supply of the nerve 1 .…”