Preservation of olfaction in anterior midline skull base meningiomas: a comprehensive approach

Abstract

Background-Olfaction is an undervalued sense in neurosurgery. Attempted surgical resection of anterior cranial fossa meningiomas puts the olfactory pathway at risk. Preservation of olfaction may increase the postoperative quality of life. Objective assessment of olfaction may inform clinical decision-making and influence the selection of operative approaches for surgical resection. Methods-We reviewed all patients who underwent surgical resection for midline anterior skull base meningiomas from July 1, 2014, through December 31, 2017. Patient demographics, tumor size, operative approach, pre-and postoperative deficits, and Simpson grade were collected and analyzed. Postoperative olfaction was assessed by clinical evaluation as well as objective evaluation using the University of Pennsylvania Smell Identification Test (UPSIT). Results-Twenty-eight patients (10 male, 18 female) were included with an average age of 53.8 years (range 27-80 years). Twenty-six patients underwent craniotomy for resection, while 2 patients had endoscopic approaches. Average tumor volume was 402.1 cm 3 (6.6-2507.7 cm 3). Preoperatively, five patients (17.8%) presented with olfactory impairment. Objectively, 50% of patients (14/28) consented and completed the UPSIT. The average postoperative UPSIT score was 25.8/40 (9/40-38/40). Two patients not identified on clinical assessment alone demonstrated postoperative olfactory deficit on UPSIT (2/14). Conclusion-There are limited published studies evaluating olfaction in patients who undergo skull-based approaches for anterior fossa meningiomas. Our series showed the highest olfaction preservation rate (87.5%) using a comprehensive strategy and multitude of surgical approaches based on the olfactory function and tumor characteristics.

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

“…Furthermore, over half of the patients (8/15) who had early postoperative olfactory dysfunction reported improvement in olfaction over the first year after surgery. Therefore, the rate of anosmia following craniotomy for TSM or PM in the present series is lower or comparable to the rates currently published in the literature 7,[20][21][22][23]42 and olfactory dysfunction in the early phases postsurgery can improve over the subsequent year.…”

Olfaction in Olfactory Groove Meningiomas

“…Algorithm flowcharts of a suitable surgical approach selection were described by Ung et al and Ottenhausen et al 30,35 According to our results, using the unilateral frontotemporal approach ensured the preservation of normal olfactory function in 62.5% of normosmic patients. The complete improvement of olfaction seems to be extremely rare when olfaction is impaired before surgery.…”

“…The reported rates of total resection ranged from 91 to 100%, permanent morbidity from 0 to 33%, and mortality from 0 to 5.4%. [2][3][4]10,28 A proper assessment of olfactory function is rarely performed, 7,29,30 and the postoperative olfactory function is infrequently reported. An unfavorable clinical outcome of the olfactory function presumably leads to an under examination of olfaction in patients with OGMs.…”

“…29 Likewise, as reported recently by Ung et al, the risk factors associated with postoperative anosmia in anterior midline skull base meningiomas, revealed by UPSIT olfaction assessment with an olfaction preservation rate of 87.5%, are larger tumor size and the presence of preoperative olfaction dysfunction. 30…”

Olfactory function testing before and after anesthesia

“…Commonly reported etiologies include sinonasal conditions, viral infection, craniofacial trauma, neurodegenerative disorders, and drugs 2 – 6 . Postoperative changes to olfactory function are often observed following sinonasal 7 – 12 and neurosurgery 13 – 17 , especially when changes occur in areas related to olfaction such as the olfactory bulb, cribriform plate, olfactory mucosa, or nasal septum. In the last 30 years, however, postoperative changes to olfaction have been also reported in other types of surgery, such as: cardiovascular 18 , 19 , abdominal 20 – 23 , and genito-urinary 24 – 26 .…”