Olfactory outcomes after endoscopic skull base surgery: A systematic review and meta‐analysis

Abstract

Objectives Determine the effect of endoscopic skull base surgery (ESBS) on long‐term olfactory outcomes after surgery. Methods An English‐language search was conducted using the Cochrane, MEDLINE, Scopus, and Embase databases from January 2000 to October 2017 for adult patients undergoing ESBS with subjective and objective olfaction outcomes. Two authors independently examined articles to identify those meeting inclusion criteria. Studies examining objective olfactory outcomes after ESBS were included in the meta‐analysis. A random‐effects meta‐analysis of patients undergoing sellar and parasellar ESBS was conducted to compare preoperative and postoperative olfactory outcomes using the University of Pennsylvania Smell Identification Test (UPSIT) and Cross‐Cultural Smell Identification Test (CCSIT). Results Among 339 eligible articles, 29 articles met inclusion criteria. Twenty‐five of these focused on sellar and parasellar tumors. Individual articles not meeting criteria for meta‐analysis were qualitatively reported. Meta‐analysis showed there was no difference in preoperative and postoperative olfactory function after sellar and parasellar ESBS based on the UPSIT (five studies, mean difference [MD] = −1.03; 95% CI: −3.98, 1.93; P = .50) and the CCIST (three studies, MD = −0.77; 95% CI: −3.03, 1.49; P = .50). A pooled overall meta‐analysis revealed similar results (eight studies, effect size = −0.30; 95% CI: −0.79, 0.18; P = .22). However, heterogeneity for all meta‐analyses was high (I2 > 95%, P < .01), suggesting significant variation in the included studies. Conclusions Based on published objective olfaction outcomes after sellar and parasellar ESBS, there was no significant difference between preoperative and postoperative olfaction. Further prospective studies using validated objective measures of olfaction are required to improve our understanding on this subject. Level of Evidence 2a Laryngoscope, 129:1998–2007, 2019

A Comparison of Olfactory and Sinonasal Outcomes in Endoscopic Pituitary Surgery Performed by a Single Neurosurgeon or a Collaborative Team of Surgeons

“…In a recent meta-analysis [13], no significant difference was found between preoperative and postoperative olfaction in patients who underwent endoscopic skull base surgery. However, an issue in that analysis was between-study heterogeneity in the surgical techniques and observation periods.…”

Superior turbinate management and olfactory outcome after endoscopic endonasal transsphenoidal surgery for pituitary adenoma: a propensity score‒matched cohort study

“…In our study, the 6‐month period gives ample time for debridement and allows the nasal mucosa to return to a baseline. Thus, it can be argued that olfactory outcome could have reached a steady state by 6 months postoperation 4 . Accordingly, a multi‐institutional, prospective trial of normosmic patients with a longer olfactory follow‐up is necessary to more accurately compare these 2 ST management techniques.…”

“…[1][2][3] The frequency and duration of this nasal morbidity vary widely, as seen in the high heterogeneity of previous studies. 4 EETS-related olfactory dysfunction theoretically arises from intraoperative loss of the olfactory nerve fibers (ONFs), and through postoperative obstruction of airflow toward the olfactory cleft due to crust formation and structural changes in the nasal cavity. 5 Nasal crusting resolves as mucociliary clearance is re-established View this article online at wileyonlinelibrary.com.…”

“…Endonasal transsphenoidal surgery (EETS) through 2 nostrils (binostril) for pituitary adenoma is common, but it sometimes contributes to postoperative olfactory dysfunction 1–3 . The frequency and duration of this nasal morbidity vary widely, as seen in the high heterogeneity of previous studies 4 . EETS‐related olfactory dysfunction theoretically arises from intraoperative loss of the olfactory nerve fibers (ONFs), and through postoperative obstruction of airflow toward the olfactory cleft due to crust formation and structural changes in the nasal cavity 5 .…”

Olfactory Outcomes after Resection of Tuberculum Sella and Planum Sphenoidale Meningiomas via a Transcranial Approach

“…2,6,37 Endonasal endoscopic strategies provide theoretical advantages such as reduced brain and nerve retraction; early decompression of the optic canal; better visualization and preservation of the superior hypophyseal artery supplying the chiasma; the absence of a cranial scar, and more rapid patient recovery when compared with traditional craniotomies. 7,25,30,40,41 Likewise, theoretical advantages of contemporary transcranial approaches include lower incidence of endocrine dysfunction, lower rates of arterial injury, and reduced risk of CSF leak. 6,7,41 Only a handful of comparisons of contemporary transcranial approaches for TSM and PM and EEAs have been performed.…”