Analysis of Olfaction after Bilateral Nasoseptal Rescue Flap Transsphenoidal Approach with Olfactory Mucosal Preservation

Comparative Analysis of Endoscope Obscuration With Utilization of an Endonasal Access Guide for Endonasal Skull Base Surgery

BACKGROUND AND OBJECTIVES

In endoscopic endonasal approaches (EEAs) for skull base pathologies, endoscope view obscuration remains a persistent, time-consuming, and distracting issue for surgeons and may result in increased operative time. The endonasal access guide (EAG) has been demonstrated as a possible adjunct to minimize these events. However, to date, there have been no comparative studies performed and the potential time savings by using EAGs have yet to be quantified. This cohort study aimed to determine the operative efficiency benefits of the EAG in EEA operations.

METHODS

Analysis of EEA operative videos from an EAG cohort (n = 20) and a control cohort (n = 20) was performed, assessing 12-minute segments in the first, middle, and last third of each operation. The first segment in each cohort was selected before EAG placement, serving as an internal control. Every endoscope lens soiling instance was counted (measured as cleaning actions per minute), timed (obscuration time %), and identified as a withdrawal, irrigation, or other cleaning action. Perioperative variables including skull base repair and postoperative cerebrospinal fluid leakage were assessed.

RESULTS

Within the EAG cohort, obscuration time was reduced in the middle and last third compared with the first third (3.73% [CI: 2.39-5.07] vs 12.97% [CI: 10.24-15.70], P < .001; 4.19% [CI: 2.83-5.55] vs 12.97% [CI: 10.24-15.70], P < .001) and cleaning actions were also significantly reduced by EAG (0.69/min [CI: 0.39-0.99] vs 1.67/min [CI: 1.34-2.00], P = .001; 0.66/min [CI: 0.35-0.97] vs 1.67/min [CI: 1.34-2.00], P < .001). Between the control and EAG cohorts, there was no significant difference between obscuration time and cleaning actions in the first third (9.33% vs 12.97%, P = .086; 1.34/min vs 1.67/min, P = .151) or in the middle third (6.24% vs 3.73%, P = .140; 0.80/min vs 0.69/min, P = .335), but there was a significant difference in the last third (9.25% [CI: 6.95-11.55] vs 4.19% [CI: 2.83-5.55], P < .001; 0.95/min [CI: 0.73-1.17] vs 0.66/min [CI: 0.35-0.97], P = .018).

CONCLUSION

EAG significantly reduces lens obscurations and cleaning events, particularly during the intradural portion of operations. This technology may offer a greater time-saving impact with patients undergoing long EEA operations.

Superiorly Based Middle Turbinate Flap for Repair of Cerebrospinal Fluid Rhinorrhea: A Cadaveric Feasibility Study and Case Series

Objectives  Cerebrospinal fluid (CSF) leaks of the anterior cranial base are frequently repaired with endonasal, multilayered reconstructions. Vascularized tissue flaps are superior to free mucosal grafts and biomaterials in many cases. Limitations of previously described flaps include reach, rotation, pedicle availability, and postoperative sinonasal morbidity. The objective of this study is to describe the superiorly based middle turbinate flap, a novel vascularized mucosal reconstruction option, and to present a case series demonstrating flap utility. Design  Cadaveric feasibility study with technical description and illustrative case series. Setting  Tertiary medical center. Participants  Three silicone-injected cadaveric specimens (6 sides); 7 patients with CSF rhinorrhea from bony dehiscence of the anterior cranial fossa repaired with a superiorly based middle turbinate flap. Outcome Measures  Cadaveric feasibility, in vivo repair outcomes, sinonasal symptoms, and postoperative healing. Results  Cadaveric dissection demonstrated a consistent vascular plexus arising from the anterior and posterior ethmoid arteries, originating at the superior attachment of the middle turbinate and traveling inferiorly to supply the mucosa of the middle turbinate. Mean surface area of the flap was 776.67 ± 114.60 mm 2 . The clinical series of 7 patients involved leaks around the cribriform plate and fovea ethmoidalis. There were no instances of repair failure. All cases showed rapid and complete remucosalization without significant sinonasal morbidity. Conclusion  The superiorly based middle turbinate flap is a reliable, versatile, and effective option for a vascularized mucosal flap onlay that can be used in anterior skull base reconstruction. This flap is particularly useful in the repair of defects involving the cribriform plate and fovea ethmoidalis.

Effects of Endoscopic Sinus Surgery on Olfactory Function

PURPOSE OF REVIEW

To review the effects of endoscopic sinus surgery and endonasal approaches to the skull base on olfaction.

RECENT FINDINGS

Advancements in endonasal endoscopic approaches to the sinuses and skull base allow for direct treatment of a variety of sinonasal and skull base diseases. However, these extended approaches will often require manipulation of normal anatomical structures and the olfactory neuroepithelium. Depending on the planned procedure and extent of disease, the prognosis of olfactory perception can vary significantly among patients. Endoscopic sinonasal surgical procedures may impact olfaction. Optimizing olfactory function requires proper surgical techniques, gentle handling of tissue, and perioperative care. Surgeons must discuss objectives and manage patient expectations. Routine olfactory assessment is crucial in surgical work-up and follow-up. Preserving anatomical structures while addressing the obstruction of the olfactory cleft helps to prevent decreased olfactory threshold. However, smell identification and discrimination do not always correlate with sinonasal anatomy.

Rhinologic outcome of endoscopic transnasal-transsphenoidal pituitary surgery: an institutional series, systematic review, and meta-analysis

PURPOSE

We aimed to summarize the available data on the objective rhinologic outcome after endoscopic transnasal-transsphenoidal (ETT) surgery.

METHODS

Retrospective study on a consecutive cohort of treatment-naïve patients undergoing ETT pituitary gland surgery. Additionally, a systematic review and meta-analysis with focus on the rhinologic outcome, including postoperative smell function was performed.

RESULTS

The institutional series incorporated 168 patients. A concomitant endoscopic septoplasty was performed in 29/168 patients (17.3%). A nasoseptal flap was used for reconstruction of large skull-base defects or high-flow CSF leaks in 4/168 (2.4%) patients. Early postoperative rhinologic complications (< 4 weeks) included epistaxis (3%), acute rhinosinusitis (1.2%) and late postoperative complications (≥ 8 weeks) comprised prolonged crusting (15.6%), symptomatic synechiae (11.9%) and septal perforation (0.6%). Postoperative smell function was not impaired (Fisher's exact test, p = 1.0). The systematic review included 19 studies on 1533 patients with a median postoperative epistaxis rate of 1.4% (IQR 1.0-2.2), a postoperative acute rhinosinusitis rate of 2.3% (IQR 2.1-3.0), a postoperative synechiae rate of 7.5% (IQR 1.8-19.1) and a postoperative septal perforation rate of 2.2% (IQR 0.5-5.4). Seven studies including a total of 206 patients reported adequate outcome measures for smell function before and after ETT surgery. Only 2/7 studies reported an impairment of smell function postoperatively, especially in patients with nasoseptal flap harvesting.

CONCLUSION

Early and late postoperative rhinologic complication rates after ETT surgery for pituitary lesions seem to be low. A thorough evaluation of smell function, in particular in patients at risk for nasoseptal flap harvesting, may be an important factor in optimal postoperative care.

Otolaryngology Considerations of Pituitary Surgery: What an Endocrinologist Should Know

Endoscopic endonasal skull base surgery is the preferred surgical approach for the management of pituitary adenomas. Perioperative management of pituitary lesions requires multidisciplinary care and typically includes a dual surgeon team consisting of a neurosurgeon and an otolaryngologist. The involvement of the otolaryngologist allows for a safe surgical approach with excellent intraoperative visualization of the tumor to enable an effective resection of the tumor by the neurosurgeon. Detection and treatment of sinonasal pathology is essential prior to surgery. Patients may experience sinonasal complaints following endoscopic transsphenoidal surgery, although this is typically temporary. Sinonasal care in the postoperative period can expedite recovery to baseline. Here we discuss the perioperative factors of endoscopic pituitary surgery that endocrinologists should be aware of, ranging from preoperative patient selection and optimization to postoperative care, with a particular emphasis on anatomic and surgical factors.

Quality of Life Considerations in Endoscopic Endonasal Management of Anterior Cranial Base Tumors

Considering quality of life (QOL) is critical when discussing treatment options for patients undergoing endoscopic endonasal skull base surgery (EESBS) for cancers at the base of the skull. Several questionnaires have been developed and validated in the last 20 years to explore QOL in this patient population, including the Anterior Skull Base Questionnaire, Skull Base Inventory, EESBS Questionnaire, and the Sino-Nasal Outcome Test for Neurosurgery. The Sino-Nasal Outcomes Test-22 and Anterior Skull Base Nasal Inventory-12 are other tools that have been used to measure sinonasal QOL in anterior cranial base surgery. In addition to pathology-related perturbations in QOL endoscopic surgical options (transsellar approaches, anterior cranial base surgery, and various reconstructive techniques) all have unique morbidities and QOL implications that should be considered. Finally, we look ahead to new and emerging techniques and tools aimed to help preserve and improve QOL for patients with anterior cranial base malignancies.

Endoscopic modified transseptal bi-nostril approach for pituitary tumors. Efficacy of complex preservation of every turbinate and olfaction: A STROBE analysis

AIMS

Endoscopic modified transseptal bi-nostril approach minimizes turbinate and olfactory mucosal invasion and ensures preservation of the turbinates and bilateral olfaction. The main objective of this study was to investigate the pre- and postoperative variations in olfactory function in patients using this approach, and the secondary objective was to investigate the complications associated with the surgical procedure.

MATERIAL AND METHODS

This study is a single-center prospective cohort study using STROBE analysis. To completely protect the bilateral turbinates and olfactory epithelium, this procedure provided access to the sphenoid sinus by a transseptal approach via the left nasal cavity and by the olfactory cleft approach via the right nasal cavity without any turbinate resection. A T&T olfactometer was used to assess the mean recognition threshold of the left, right, and bilateral nasal passages before and after surgery, and complications associated with the surgical approach were investigated.

OBJECTIVES

We included 27 patients who underwent endoscopic modified transseptal pituitary surgery with an olfactory and turbinate preservation approach at our hospital between April 2018 and December 2019.

RESULTS

The mean postoperative recognition threshold of the right, left, and bilateral nasal cavities did not worsen (P<0.001 for all) relative to the preoperative values, and there was no difference in values between the right and left nasal cavities (P=0.85). The nasal turbinates were preserved in all patients during the study period, and no recurrence was observed.

CONCLUSION

Our modified EETSA could be implemented as an approach for turbinate and olfaction preservation.

Systematic Review of Olfactory Outcomes After Nasoseptal Flap Harvest for Endoscopic Skull Base Surgery: Does Using Cold Steel or Olfactory Strip Preservation Matter?

BACKGROUND

Several studies have described techniques aimed at mitigating olfactory dysfunction after nasoseptal flap (NSF) harvest for endoscopic skull base surgery (ESBS). No consensus exists as to whether popular methods including using cold-steel (CS) versus electrocautery (EC) or septal olfactory strip (SOS) preservation offer an advantage. This systematic review was performed to examine the impact of these two technical variations of NSF harvest on postoperative olfactory outcomes.

METHODS

Following PRISMA guidelines, Pubmed, Scopus, and Web of Science were searched for articles reporting olfactory outcomes in ESBS cases employing a NSF. Original articles focusing on technique variations of the NSF and reporting at least 1 objective olfactory measure were included.

RESULTS

Nine studies comprising 610 patients were included. Various, olfactory testing outcomes were reported, and post-op follow-up ranged from 6 weeks to 12 months. Three studies, including a randomized-controlled trial, compared the use of CS and EC for the superior incision of the NSF. No significant difference was found in objective olfactory function (p>0.05) when comparing these techniques. Five studies comprising 504 patients reported results from SOS sparing. SOS sparing technique in NSF harvest demonstrated smell preservation in the post-op setting when compared to pre-op measures (p>0.05), however, no direct comparison to non-SOS sparing techniques was made.

CONCLUSION

Use of CS as opposed to EC for the superior NSF incision does not appear to confer an advantage in preserving post-op olfactory function (grade B evidence). SOS preservation may be associated with better olfactory outcomes in NSF harvest (grade C evidence). This article is protected by copyright. All rights reserved.

Complication avoidance protocols in endoscopic pituitary adenoma surgery: a retrospective cohort study in 514 patients

PURPOSE

To evaluate the impact of using consistent complication-avoidance protocols in patients undergoing endoscopic pituitary adenoma surgery including techniques for avoiding anosmia, epistaxis, carotid artery injury, hypopituitarism, cerebrospinal fluid leaks and meningitis.

METHODS

All patients undergoing endoscopic adenoma resection from 2010 to 2020 were included. Primary outcomes included 90-day complication rates, gland function outcomes, reoperations, readmissions and length of stay. Secondary outcomes were extent of resection, short-term endocrine remission, vision recovery.

RESULTS

Of 514 patients, (mean age 51 ± 16 years; 78% macroadenomas, 19% prior surgery) major complications occurred in 18(3.5%) patients, most commonly CSF leak (9, 1.7%) and meningitis (4, 0.8%). In 14 of 18 patients, complications were deemed preventable. Four (0.8%) had complications with permanent sequelae (3 before 2016): one unexplained mortality, one stroke, one oculomotor nerve palsy, one oculoparesis. There were no internal carotid artery injuries, permanent visual worsening or permanent anosmia. New hypopituitarism occurred in 23/485(4.7%). Partial or complete hypopituitarism resolution occurred in 102/193(52.8%) patients. Median LOS was 2 days; 98.3% of patients were discharged home. Comparing 18 patients with major complications versus 496 without, median LOS was 7 versus 2 days, respectively p < 0.001. Readmissions occurred in 6%(31/535), mostly for hyponatremia (18/31). Gross total resection was achieved in 214/312(69%) endocrine-inactive adenomas; biochemical remission was achieved in 148/209(71%) endocrine-active adenomas. Visual field or acuity defects improved in 126/138(91.3%) patients.

CONCLUSION

This study suggests that conformance to established protocols for endoscopic pituitary surgery may minimize complications, re-admissions and LOS while enhancing the likelihood of preserving gland function, although there remains opportunity for further improvements.

Olfactory-Specific Quality of Life Outcomes after Endoscopic Endonasal Surgery of the Sella

Objective

To assess olfactory outcomes as measured by an olfactory-specific quality of life (QOL) questionnaire in patients undergoing EESBS for sellar lesions.

Design

Retrospective case series.

Setting

Tertiary academic medical center.

Participants

In total, 36 patients undergoing EESBS for lesions limited to the sella were evaluated.

Main Outcome Measures

The following were performed before and three months after surgery: 22-Item Sinonasal Outcomes Test (SNOT-22), University of Pennsylvania Smell Identification Test (UPSIT), and the Assessment of Self-reported Olfactory Functioning (ASOF), which has three domains: subjective olfactory capability scale (SOC), smell-related problems (SRP), and olfactory-related quality of life (ORQ).

Results

Median age at surgery was 52.5 years, with a median tumor size of 1.8 cm (range: 0.2 to 3.9 cm). Pre- and postoperative median scores were 35 [34, 36.2] and 34.5 [32, 36] for UPSIT, 21 [7.5, 33.5] and 21.5 [6.8, 35.7] for SNOT-22, 10 [9, 10] and 9 [8, 10] for ASOF-SOC, 5 [4.8, 5] and 4.5 [4, 5] for ASOF-SRP, and 5 [5, 5] and 5 [4.5, 5] for ASOF-ORQ. There was no significant change in the two of the three domains of the ASOF. Correlation between ASOF and UPSIT scores were weak. Older age and larger tumor size were associated with worsened olfaction after surgery.

Conclusions

Patients did not experience significant changes in olfactory-specific QOL three months after EESBS, as measured by two domains of the ASOF. The ASOF may serve as a useful adjunctive tool for assessing olfaction after surgery. The lack of correlation between UPSIT and ASOF suggests the need for more research in subjective olfactory-related quality of life after surgery.

Modified Nasoseptal Rescue Flap Technique for Pituitary Adenoma Resection via Endoscopic Endonasal Approach

ABSTRACT

Nasoseptal rescue flap (NSRF), which preserves the pedicle of the flap and is harvested as a nasoseptal flap (NSF) when intraoperative leakage of cerebrospinal fluid (CSF) occurs, is an alternative strategy for skull base reconstruction in patients with pituitary adenoma resection via an endoscopic endonasal approach. However, in practice, the original NSRF technique cannot meet the needs during operation. Therefore, the authors aimed to describe a modified NSRF technique for the resection of pituitary adenoma via endoscopic endonasal approach and to examine its utility and outcomes. The authors retrospectively analyzed the medical records of 87 consecutive patients with pituitary adenoma who underwent endoscopic endonasal surgery performed using NSRF technique from September 2019 to August 2020. Data on intraoperative CSF leakage, NSF conversion rate, and reconstruction-related complications were analyzed. The average age of patients was 50.1 years (men, 50.5%). Twenty-five cases of intraoperative CSF leakage were observed: 23 cases of low-flow CSF leakage and two cases of high-flow CSF leakage. NSRF was converted to NSF in 11 cases. Two patients experienced postoperative CSF leakage after reconstruction without NSF and required unplanned reoperation to rebuild the skull base with NSF. In conclusion, this modified NSRF utilized a minimally invasive way to provide sufficient surgical corridor without the need for pedicle retraction, and it can be effectively converted to an NSF for skull base reconstruction in patients with pituitary adenoma.

Impact of Routine Endoscopic Skull Base Surgery on Subjective Olfaction and Gustation Outcomes

BACKGROUND

As endoscopic endonasal skull base surgery (EESBS) for sellar pathology has become routine, there is increasing awareness of quality-of-life (QOL) outcomes related to this approach. Similarly, there is a growing interest in postoperative chemosensory function, with notable emphasis on olfaction and the corresponding psychosocial implications of olfactory dysfunction. Meanwhile, there has been minimal direct investigation into gustatory outcomes, and the association between these 2 chemosensory functions remains poorly understood.

OBJECTIVE

To investigate patient-reported chemosensory function and rhinologic-specific QOL following EESBS for routine sellar pathologies.

METHODS

Comprehensive clinical characteristics and sinonasal QOL assessments, measured using Anterior Skull Base Nasal Inventory-12 (ASK Nasal-12), were collected from 46 patients undergoing EESBS for sellar pathology.

RESULTS

Forty-six patients were included: 65.2% female, average age 52.8 yr (range: 27-89). The most common pathology was nonfunctioning pituitary adenoma (n = 28). Preoperative ASK Nasal-12 scores (mean = 0.81) demonstrated postoperative worsening at 2 wk (mean = 2.52, P < .0001) and 1 mo (mean = 1.33, P = .0031), with no difference at 3 mo postoperatively (mean = 0.89, P = .92). Meanwhile, there was significant worsening of preoperative subjective smell (mean = 0.62) and taste function (mean = 0.42) at 2 wk (mean = 3.48, P < .0001; mean = 2.69, P < .0001) and 1 mo (mean = 2.40, P < .0001; mean = 2.03, P < .0001) postoperatively, which persisted at approximately 3 mo postoperatively (mean = 1.26, P = .04; mean = 1.15, P = .0059).

CONCLUSION

Patients undergoing EESBS for sellar pathologies experience anticipated, temporary disruptions in sinonasal QOL but may have longer lasting perturbations in subjective olfaction and gustation. Given the increasing use of the endoscopic endonasal corridor, further investigation in postoperative chemosensory function is essential.

Pituitary adenomas in older adults (≥ 65 years): 90-day outcomes and readmissions: a 10-year endoscopic endonasal surgical experience

INTRODUCTION

Longer lifespan and newer imaging protocols have led to more older adults being diagnosed with pituitary adenomas. Herein, we describe outcomes of patients ≥ 65 years undergoing endoscopic adenoma removal. To address selection criteria, we also assess a conservatively managed cohort.

METHODS

A retrospective analysis of 90-day outcomes of patients undergoing endoscopic pituitary adenomectomy from 2010 to 2019 by a neurosurgical/ENT team was performed. Tumor subtype, cavernous sinus invasion, extent of resection/early remission, endocrinology outcomes, complications, re-operations and readmissions were analyzed. A comparator cohort ≥ 65 years undergoing clinical surveillance without surgery was also analyzed.

RESULTS

Of 468 patients operated on for pituitary adenoma, 123 (26%) were ≥ 65 years (range 65-93 years); 106 (86.2%) had endocrine-inactive adenomas; 18 (14.6%) had prior surgery. Of 106 patients with endocrine-inactive adenomas, GTR was achieved in 70/106 (66%). Of 17 patients with endocrine-active adenomas, early biochemical remission was: Cushing's 6/8; acromegaly 1/4; prolactinomas 1/5. Gland function recovery occurred in 28/58 (48.3%) patients with various degrees of preoperative hypopituitarism. New anterior hypopituitarism occurred in 3/110 (2.4%) patients; permanent DI in none. Major complications in 123 patients were: CSF leak 2 (1.6%), meningitis 1 (0.8%), vision decline 1 (0.8%). There were no vascular injuries, operative hematomas, anosmia, deaths, MIs, or thromboembolic events. Median length of stay was 2 days. Readmissions occurred in 14/123 (11.3%) patients, 57% for delayed hyponatremia. Intra-cohort analysis by age (65-69, 70-74, 75-79,  ≥ 80 years) revealed no outcome differences. Cavernous sinus invasion (OR 7.7, CI 1.37-44.8; p = 0.02) and redo-surgery (OR 8.5, CI 1.7-42.8; p = 0.009) were negative predictors for GTR/NTR. Of 105 patients evaluated for presumed pituitary adenoma beginning in 2015, 72 (69%) underwent surgery, 8 (7%) had prolactinomas treated with cabergoline and 25 (24%) continue clinical surveillance without surgery, including two on new hormone replacement.

CONCLUSION

This study suggests that elderly patients carefully selected for endoscopic adenoma removal can have excellent short-term outcomes including high resection rates, low complication rates and short length of stay. Our experience supports a multidisciplinary approach and the concept of pituitary centers of excellence. Based on our observations, approximately 25% of elderly patients with pituitary adenomas referred for possible surgery can be monitored closely without surgery.

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

Background

Surgical management of the superior turbinate (ST) is required to access the sella in endoscopic endonasal transsphenoidal surgery (EETS) for pituitary adenoma. Two common ST management techniques include partial resection of the ST (PRST) and intentional lateralization of the ST (ILST). Given the concentrated distribution of the olfactory nerve fibers on the medial surface of the ST, in this study we aimed to ascertain whether PRST worsens the objective olfactory outcome when compared with ILST.

Methods

A retrospective, propensity score‒matched cohort study was performed at a tertiary referral center. A total of 232 adult patients undergoing EETS for pituitary adenoma were analyzed. The threshold test (STT) and the 12‐item identification test (SIT‐12) from “Sniffin’ Sticks” were administered for separate nostrils preoperatively and 6 months postoperatively.

Results

Of 232 patients, 109 had right‐sided PRST and 123 received right‐sided ILST. Propensity score matching—controlling for olfactory‐related confounding factors, including gender, age, medical comorbidities, surgical technique, and preoperative olfaction—resulted in 74 matched pairs. When comparing the 6‐month postoperative olfactory performance of the right nostril, the STT score was significantly lower in the PRST group than the ILST group (p = 0.036, η² for effect size estimate = 0.030), but the SIT‐12 scores were similar in the 2 groups (p = 0.325). Overall, the olfactory outcomes for the right nostril did not qualitatively differ between the PRST and ILST groups (p = 0.401).

Conclusion

Despite its association with threshold impairment, PRST in EETS does not seem to carry an additional risk of postoperative olfactory dysfunction.

Endoscopic Study of the Distribution of Olfactory Filaments: A Cadaveric Study

Objective

Provide a detailed anatomical description of the olfactory filaments (OF) and their distribution in the nasal cavity through endoscopic endonasal dissection.

Methods

Four cadaveric specimens (8 sides) were used in this study. Nasoseptal (NSM), middle (MTM) and superior turbinate (STM) mucosa dissection was performed to identify the OF and follow them superiorly to the cribriform plate (CP). Measurements of the OF were taken on the NSM, MTM, STM under direct endoscopic visualization. A Student’s T-Test was performed to compare means.

Results

The NSM contained a mean of 11 OF, distributed over surface area (SA) of 173 ± 31 mm2 with the highest density of OF being found at the posterior NSM. The MTM contained a mean 6 OF, covering a mean SA of 77 mm2, with the first OF found 5 mm from the anterior border of the MTM, on average. The STM had a mean 9 OF, with the OF covering a mean SA of 96 mm2. Overall mean OF length was 6 mm. The STM OF were significantly greater in number, with a greater distance from the first OF to last OF (p < 0.05) than the MTM OF.

Summary

The STM and MTM combined were found to have a greater density of OF than the NSM. The STM contains a significantly greater number of OF covering a greater area than the MTM OF. Preservation of the STM and MTM in skull base defect repair, and in routine sinus surgery, can be as beneficial for olfactory function as preservation of the NSM; particularly in CP defect repair. Moreover, our findings indicate that nasoseptal flap harvest performed at least 6 mm from the skull base preserves OF in the NSM. To our knowledge, this is the first anatomical study of the OF through direct endoscopic observation and measurements.

Evaluation of olfactory function in patients undergoing endoscopic skull base surgery with nasoseptal flap

Introduction

Endoscopic transnasal access to the skull base, both for treatment and reconstruction, can cause olfactory morbidity. Knowing the main consequences of this intervention is essential to have objective criteria for decision-making regarding the appropriate surgical technique.

Objectives

The aim of this study is to determine the impact on olfactory function of the endonasal endoscopic access to the skull base with the creation of the nasoseptal flap.

Methods

A prospective research was carried out in which 22 patients who underwent endoscopic transnasal surgery at the skull base, with the creation of a nasoseptal flap. The Connecticut Chemosensory Clinical Research Center test was applied before and at the 1^st, 3^rd and 6^th postoperative months.

Results

The results showed that only in the first month of follow-up the mean patient classification was statistically worse than at the other evaluation moments (p < 0.05), but there was no mean difference in the Connecticut score classification between the other moments (p > 0.05); that is, patients showed worsening in the 1^st month and returned to the preoperative mean after the 3^rd month of follow-up.

Conclusion

The present study showed that the postoperative decrease in olfaction is transient, since the patient's sense of smell returns to pre-surgical values in the 3^rd postoperative month.