Olfactory outcomes after endonasal skull base surgery: a systematic review

Comparison of Sinonasal Outcomes in Patients Undergoing Uni-nostril and Bi-nostril Endoscopic Trans-sphenoidal Excision of Pituitary Adenomas: A Prospective Study

Background  Prospective studies comparing quality-of-life and olfaction in patients undergoing endoscopic uni-nostril versus bi-nostril trans-sphenoidal pituitary surgery have not been published. Methods  We prospectively compared olfaction and quality-of-life at baseline and at 3 to 6 months follow-up using the Anterior Skull Base Nasal Inventory-12 (ASK-12) questionnaire, composite olfaction score, and Lund-Kennedy Endoscopic Score (LKES) in 43 patients who underwent endoscopic excision of pituitary adenoma with either a uni-nostril (24 patients) or a bi-nostril (19 patients) approach. Results  Baseline data for both groups were comparable. In the uni-nostril group, ASK-12 and LKES scores were not significantly different at follow-up when compared with the preoperative scores. In the bi-nostril group, there was a significant postoperative worsening of ASK-12 scores (mean: 3.2 vs. 5.3; p  = 0.04) and the LKES (mean: 2.9 vs. 6.6; p  = 0.01). Composite olfaction score was not significantly affected postoperatively with either approach. Nasal complications were also more in the bi-nostril group (5/18, 27.8% vs. 1/23, 4.3%) but this was not statistically significant ( p  = 0.07). Conclusion  Both approaches preserve olfactory function but the uni-nostril approach is associated with better postoperative quality-of-life and endoscopic scores and subjective olfaction outcomes. At least in short term, the postoperative morbidity is higher in the bi-nostril approach compared with the uni-nostril approach. Although preference for a particular approach is related to a surgeon's preference, preoperative counselling of the patients regarding sinonasal morbidity is important.

Incidence and influencing factors of olfactory dysfunction in patients 1 week after endoscopic transsphenoidal resection of pituitary tumor: a cross-sectional study of 158 patients

Objective

To investigate the current situation of olfactory dysfunction in patients after endoscopic transsphenoidal resection of pituitary tumors, and analyze its influencing factors, to provide references for clinical nursing and rehabilitation.

Methods

A cross-sectional study design and convenience sampling method were used to investigate 158 patients with pituitary tumors treated by endoscopic transsphenoidal pituitary tumor resection in the Department of Neurosurgery of three Grade-A general hospitals in Sichuan Province from January 2022 and June 2023. The olfactory function of patients was evaluated 1 week after surgery, and the general clinical data and olfactory related data of patients were collected, and the influencing factors of olfactory disorder were analyzed by logistic regression.

Results

The incidence of olfactory dysfunction was 73.42%. analysis revealed that the formation of blood scabs, nasal cavity adhesion, cerebrospinal fluid leakage and operation time were independent risk factors for olfactory dysfunction in patients after transsphenoidal pituitary tumor resection (p < 0.05).

Conclusion

The incidence of olfactory dysfunction is high in patients after endoscopic transsphenoidal resection of pituitary tumors, suggesting that medical staff should pay close attention to and identify patients with olfactory dysfunction based on the guidance of disease knowledge and skills, develop targeted nursing interventions, and promote the improvement of patients' olfactory function and quality of life.

Effect of endoscopic endonasal skull base approaches on olfactory function and facial development in children

INTRODUCTION

Endoscopic approaches for skull base pathologies are increasingly being performed, and the subsequent complications, especially in the long term, have also been partially clarified. However, there is no information on the effects of endoscopic endonasal skull base surgeries (EESBS) in children on odor and facial development in parallel with long-term development. We conducted this study to investigate postoperative olfactory function and facial development in pediatric patients who underwent skull base surgery using the endoscopic endonasal method.

METHODS

We evaluated the smell test, sinonasal symptoms, and facial development of pediatric patients who underwent endoscopic endonasal skull base surgery after long-term follow-up. Odor was evaluated using the "Sniffin' Sticks" test kit, which assessed the T (odor threshold), D (odor discrimination), and I (odor identification) parameters. Sinonasal symptoms were evaluated using the SNOT-22 (sinus-nose outcome test) questionnaire. SNA (sella-nasion-A point), SNB (sella-nasion-B point), and ANB (A point-nasion-B point) angles were calculated from maxillofacial tomography and magnetic resonance imaging) to evaluate facial development. Data were compared with those of the healthy control group.

RESULTS

We included 30 patients comprising 19 (63.3%) boys and 11 (36.7%) girls, with no age difference between case and control groups. The mean follow-up period was 7 years. Odor test data, cephalometric measurements, and SNOT-22 analysis results showed no statistically significant differences between the two groups.

CONCLUSION

To our knowledge, this is a comprehensive study with the longest follow-up period in terms of evaluation of facial development after EESBS in children to analyze odor using the Sniffin' Sticks test kit and the quality of life using SNOT-22. Olfactory function, facial development, and quality of life remained unaffected after long-term follow-up after EESBS  in children. Although this surgical approach is minimally invasive, we recommend considering the possibility of complications, and the procedure should be performed by an experienced surgical team with adequate equipment.

Validation of Korean Olfactory Questionnaire for Perioperative Olfactory Assessment in Endoscopic Endonasal Skull Base Surgery

Objective: To analyze changes in olfactory function after endoscopic endonasal skull base surgery and compare performance of the olfactory questionnaire with those of conventional psychophysical tests. Methods: Patients were classified into 5 categories for olfactory function evaluation (normal, mild hyposmia, moderate hyposmia, severe hyposmia, and anosmia) based on a self-assessment. Patients also underwent the butanol threshold test (BTT), Cross-Cultural Smell Identification Test (CCSIT), and 11-item olfactory questionnaire. Subjects with normosmia preoperatively and who were followed up at least 6 months after surgery were analyzed. Receiver operating characteristic curves and confusion matrix analysis were performed for BTT, CCSIT, and olfactory questionnaire to compare their diagnostic abilities. The effects of age, preoperative olfaction, septal flap, tumor pathology, and tumor size on postoperative olfaction were evaluated using multivariate linear regression analysis. Results: Data from 108 patients were analyzed. Postoperative changes in the olfactory questionnaire were significantly associated with changes in the BTT and CCSIT. The area under the curve for postoperative self-olfactory function classification was highest for olfactory questionnaire (0.894), followed by BTT (0.767) and CCSIT (0.688). Patient age at the time of surgery and preoperative BTT score were significantly related to postoperative olfactory outcomes. Conclusion: The olfactory questionnaire correlated well with conventional psychosomatic olfactory function tests. In combination with clinical parameters and preoperative psychosomatic olfactory function tests, the olfactory questionnaire is suitable for assessing subjective olfactory function after endoscopic endonasal skull base surgery.

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.

Olfactory changes after endonasal endoscopic cerebrospinal fluid fistula repair: long-term outcomes

OBJECTIVE

This study aimed to evaluate odour measurements after endoscopic repair of cerebrospinal fluid fistulas.

METHOD

Demographic characteristics, cerebrospinal fluid leak location, surgical procedure, aetiology and smell test results were retrospectively reviewed.

RESULTS

A total of 27 patients were included. The mean age was 43.52 years. The aetiology was spontaneous in 13 patients (48.1 per cent) and traumatic in 14 patients (51.9 per cent). The skull base defect was at the cribriform plate in 15 patients (55.6 per cent), the frontal sinus posterior wall in 4 patients (14.8 per cent), the sphenoid sinus posterior wall in 4 patients (14.8 per cent), around the anterior ethmoid artery in 2 patients (7.4 per cent), at the ethmoid roof in 1 patient (3.7 per cent) and at the sphenoid sinus posterolateral wall in 1 patient (3.7 per cent). After the comparison of pre-operative and post-operative values in identification, discrimination and threshold categories, a statistically significant difference was seen only in the threshold category (p = 0.014).

CONCLUSION

The results demonstrated that endoscopic repair of cerebrospinal fluid leak is safe in terms of olfactory functions.

Is nasal airflow disrupted after endoscopic skull base surgery? A short review

Even the most delicate endonasal surgery for skull base lesion causes changes in the nasal cavity, some of them permanent. Morphological changes in the nasal cavity and their consequences (changes in nasal airflow) are often studied by advanced numerical analysis called computational fluid dynamics. This review summarizes current knowledge of endoscopic transsphenoidal skull base surgery effects on nasal airflow. Several studies have shown that endoscopic skull base surgery changes nasal anatomy to the extent that nasal airflow changes significantly postoperatively. Removing any intranasal structure increases the cross-sectional area of the respective nasal meatus, leading to increased nasal airflow in this area while airflow in the narrower periphery decreases. Middle turbinate resection increases airflow in the middle meatus and reduces airflow in the superior and inferior meatus. Small posterior septectomy does not cause a significant change in nasal airflow. Nasal septum deviation is an important factor in airflow changes. Current studies describe nasal changes after rather extensive procedures (e.g., middle turbinectomy, ethmoidectomy) that are unnecessary in routine pituitary adenoma surgery. No studies have compared changes using pre- and postoperative scans of the same patients after actual surgery.

One-and-a-half nostril versus binostril endoscopic transsphenoidal approach to the pituitary adenomas: A prospective randomized controlled trial

Background

Binostril endoscopic transsphenoidal approach (BETA) is the most used approach for sellar lesions nowadays, while its damage to the nasal structures may cause nasal discomfort and affect nasal functions including respiration and olfaction. With the purpose to improve the post-operative sinonasal quality of life (QoL), we introduced the one-and-a-half nostril endoscopic transsphenoidal approach (OETA) in 2016 which preserved more natural structures and registered a prospective randomized controlled trial (ChiCTR-IOR-16008222) to compare the two approaches regarding the surgical outcomes and complications.

Methods

Sixty patients with pituitary adenomas were recruited and randomly assigned to the OETA group and the BETA group between April 2016 and May 2017 in Jinling Hospital. The tumor resection rate, endocrinal and visual outcomes, and surgical complications between the OETA and BETA groups were analyzed. Besides, the questionnaire Anterior Skull Base Nasal Inventory-12 (ASK Nasal-12) was used to evaluate patients’ sinonasal QoL at seven time points (pre-operative; 2-weeks, 1-month, 3-months, 6-months, 12-months, and long-term post-operatively). The Sniffin’ Sticks were used to assess patients’ olfactory function objectively in a long term. Each patient was followed for at least 12 months post-operatively.

Results

There was no significant difference in tumor resection rate, hormonal and visual outcomes, and surgical complications between the two groups. Regarding the ASK Nasal-12, patients in the OETA group complained less about dried nasal material at 2 weeks after surgery (P = 0.017). One month after surgery, the OETA group had better olfaction function (P = 0.019) compared with the BETA group. However, there was no significant difference in early and long-term postoperative sinonasal QoL between the two approaches according to the entire ASK Nasal-12 metric. The results of the Sniffin’ Sticks showed that the two groups had a similar olfactory performance at long-time follow-up.

Conclusion

In this single tertiary center trial, the results showed that the OETA achieved the same surgical outcomes and post-operative sinonasal QoL as the BETA.

Clinical Trial Registration

http://www.chictr.org.cn/showproj.aspx?proj=13852, identifier: ChiCTR-IOR-16008222

Olfaction after endoscopic surgery for sellar and parasellar disease: an updated systematic review and meta-analysis

Background: Whether endoscopic surgery for sellar/parasellar disease causes significant deficits in olfactory function remains unclear. We aimed to systematically review the olfactory outcomes in such settings based on the evidence up to date. Methods: PubMed, EMBASE, and CENTRAL were searched through February 1, 2021. Included studies were limited to endoscopic surgery for sellar/parasellar disease with follow-up olfactory function measured by standardized olfactory testing methods or subjective assessment. The primary outcome was the change in olfactory function after surgery assessed by standardized olfactory testing methods. The secondary outcome was the change in subjective olfactory function. Random-effects model was used in obtaining combine effects. Study quality was assessed using the Newcastle–Ottawa scale. Sensitivity analysis was carried out using the leave-one-out approach, and publication bias was assessed using Egger’s test. Results: The results show no significant difference in olfaction assessed by standardized olfactory testing methods at 1–3 months post-surgery (880 patients in 16 studies) or at 6–12 months post-surgery (1320 patients in 16 studies) compared to pre-surgery, whereas a significantly lower subjective olfaction at 3 months was observed. In addition, the lack of significant change in olfaction as assessed by standardized olfactory testing methods was observed regardless of whether patients were treated with or without the nasoseptal flap (NSF) harvesting. Heterogeneity and publication bias were observed, whereas sensitivity analysis showed the meta-analysis results are robust. Conclusion: The findings of this updated systematic review and meta-analysis support the conclusion that endoscopic surgery for sellar and parasellar pathology may pose no greater risk of olfactory dysfunction. In addition, the current evidence does not support there is an increased risk of diminished olfaction among patients treated with NSF during surgery.

Changes in olfactory function and olfactory bulb after treatment for acromegaly

PURPOSE

This study aimed to investigate the olfactory functions of the acromegaly patients and to discuss the possible causes of olfactory dysfunction in acromegaly patients.

METHODS

A case-control study was carried out in a tertiary referral center. 52 patients with acromegaly (Acromegaly group) and 52 healthy individuals (Control group) were included in the study. All acromegaly patients included in the study were in the late postoperative period. The Connecticut Chemosensory Clinical Research Center (CCCRC) test was carried out and olfactory bulb (OB) volumes were measured in both of the groups.

RESULTS

There was a significant difference between the mean CCCRC total scores of the acromegaly and control groups (p = .000). The mean of right and left OB volumes in the acromegaly group was significantly higher than the control group (p = .004) CONCLUSION: In this study, we found that acromegaly patients are likely to experience olfactory dysfunction. It is important to examine these patients' olfactory functions at the time of diagnosis and clinic follow-up.

CLINICAL TRIAL NUMBER

NCT04138537.