Taste impairment after endoscopic stapes surgery: Do anatomic variability of chorda tympani and surgical technique matter? : Post-operative dysgeusia after EStS

Accurate Segmentation and Tracking of Chorda Tympani in Endoscopic Middle Ear Surgery with Artificial Intelligence

Objective: We introduce a novel endoscopic middle ear surgery dataset specifically designed for evaluating deep learning (DL)-based semantic segmentation of chorda tympani. Methods: We curated a dataset comprising 8240 images from 25 patients, divided into a training set (20%, 1648 images), validation set (5%, 412 images), and test set (75%, 6180 images). We employed data enhancement techniques to expand the picture size of the training and validation sets by 5 times (training set: 8240 images, verification set: 2060 images). Subsequently, we employed a multistage transfer learning training method to establish, train, and validate various convolutional neural networks. Results: On the validation set of 2060 labeled images, our proposed network achieved good results, with the U-net exhibiting the highest effectiveness (mIOU = 0.8737, mPA = 0.9263). Furthermore, when applied to the test dataset of 6180 raw images and contrasted with the prediction of otologists, the overall performance of the U-net was excellent (accuracy = 0.911, precision = 0.9823, sensitivity = 0.8777, specificity = 0.9714). Conclusions: Our findings demonstrate that DL can be successfully employed for automatic segmentation of chorda tympani in endoscopic middle ear surgery, yielding high-performance results. This study validates the potential feasibility of future intelligent navigation technologies to assist in endoscopic middle ear surgery.

Brazilian Society of Otology task force - Otosclerosis: evaluation and treatment

OBJECTIVES

To review and provide evidence-based recommendations for the diagnosis and treatment of otosclerosis.

METHODS

Task force members were educated on knowledge synthesis methods, including electronic database search, review and selection of relevant citations, and critical appraisal of selected studies. Articles written in English or Portuguese on otosclerosis were eligible for inclusion. The American College of Physicians' guideline grading system and the American Thyroid Association's guideline criteria were used for critical appraisal of evidence and recommendations for therapeutic interventions.

RESULTS

The topics were divided into 2 parts: 1) Diagnosis - audiologic and radiologic; 2) Treatment - hearing AIDS, pharmacological therapy, stapes surgery, and implantable devices - bone-anchored devices, active middle ear implants, and Cochlear Implants (CI).

CONCLUSIONS

The pathophysiology of otosclerosis has not yet been fully elucidated, but environmental factors and unidentified genes are likely to play a significant role in it. Women with otosclerosis are not at increased risk of worsening clinical condition due to the use of contraceptives or during pregnancy. Drug treatment has shown little benefit. If the patient does not want to undergo stapedotomy, the use of hearing aids is well indicated. Implantable systems should be indicated only in rare cases, and the CI should be indicated in cases of profound deafness.

The utility and safety of diode laser in endoscopic stapes surgery

Objective

The advantages of laser stapedotomy are less trauma and more precise and minimally invasive techniques; however, the potential risk of overheating from the laser combined with the endoscope tip must be considered. This study aimed to assess the efficacy and safety of diode lasers for endoscopic stapes surgery.

Methods

A retrospective review of 56 patients with otosclerosis who underwent primary endoscopic stapedotomy with a diode laser from 2017 to 2020 was conducted. Demographic data, intraoperative findings, preoperative and postoperative audiological assessments, and postoperative complications were analyzed.

Results

There was no statistically significant difference between the preoperative and postoperative bone conduction thresholds. The mean postoperative air-bone gap (ABG) improved significantly compared to the preoperative ABG (4.07 vs. 35.43 dB, p < .001). The postoperative ABG closure within 10 dB at 6 and 12 months was achieved in 87.50% and 91.07% of patients, respectively. The postoperative pain scores at 4 and 24 h were 2.55 and 0.39, respectively. Immediate postoperative vertigo was reported in 12.50% of patients, with 100% complete recovery 2 months after surgery. The chorda tympani nerve was preserved in all the cases. Postoperative taste disturbances at 2 and 12 months were observed in 17.86% and 1.79% of patients, respectively.

Conclusion

The diode laser in endoscopic stapedotomy is a safe and effective technique that provides satisfactory hearing outcomes. Temporary taste disturbances during the early postoperative period are a concern. The handheld diode laser delivery system is suitable for an endoscopic approach and is an alternative armamentarium for the treatment of otosclerosis. Level of evidence: IV.

Comparison of endoscopic and microscopic methods in stapedotomy: a retrospective analysis

PURPOSE

The goal of the present study was to compare the audiologic results, complications, and advantages/disadvantages of endoscopic and microscopic stapedotomy.

METHODS

Patients who experienced stapedotomy surgery in the Ear Nose Throat Clinic (ENT) of Selcuk University Faculty of Medicine between September 2011 and January 2018 were included in the study. The data of all patients were analyzed and divided into two groups. Those who underwent endoscopic stapedotomy were included in group I, and patients who underwent microscopic stapedotomy formed group II. Surgical findings, complications, and operation times were compared for the two groups. Air and bone conduction thresholds were evaluated at the frequencies of 500, 1000, 2000, and 4000 Hz pre- and postoperatively at 1, 3, and 6 months, and the mean (± SD) air-bone gap value was recorded.

RESULTS

While the mean pre- and postoperative air-bone gaps were 34.38 ± 7.47 dB (23-53 dB) and 9.69 ± 4.43 dB (0-19 dB), respectively, in group I, 34.32 ± 7.57 dB (23-6 dB) and 9.62 ± 4.25 dB (2-23 dB) were the respective means calculated in group II (p < 0.05). When the mean postoperative air-bone gap was compared, there was no statistically significant difference between the two groups (p = 0.774). The mean operative times for groups I and II were 57.22 ± 4.37 min and 63.70 ± 7.34 min, respectively (p < 0.001). The requirement for chorda tympani nerve manipulation and scutum curettage was significantly less in group I compared to group II (p = 0.003). Postoperative dysgeusia and postoperative pain were found to be higher in group II than group I, but they were not statistically significant (p > 0.05).

CONCLUSION

Endoscopic stapedotomy displayed similar audiological results, shorter operation times, and similar complication rates, as well as being a less invasive surgery, compared to the microscopic approach.

“Hot” vs “Cold” endoscopic stapes surgery: a matched case–control study

Purpose

To compare hearing results and complication rates between two groups of patients operated on by endoscopic stapes surgery (ESS) for otosclerosis, either with CO2 fiber laser or microdrill.

Methods

A case–control study was performed. All consecutive cases of CO2 fiber laser ESS operated at a single center during the period 2017–2020 (case group) were matched to a control group of patients operated by traditional technique, according to year of surgery, preoperative mean air–bone gap, sex and age. Audiological data from preoperative and postoperative examinations and complication rates were compared.

Results

46 cases were included. Mean operative time was significantly longer in the laser cohort (65 min) than in the drill one (45 min) (p = 0.003). Similar results were found in the two groups regarding the mean postoperative BC-PTA. The high-frequency bone conduction resulted significantly higher in the laser group (p = 0.002), suggesting an overclosure effect in the laser group. Consistently, a significant improvement of the BC-PTA threshold at 2000 Hz postoperatively was found in the laser group (p = 0.034). The postoperative AC-PTA significantly improved in both groups at all frequencies (p < 0.05), except for the AC threshold at 8 kHz. Similar rates of complications were found in the two groups.

Conclusion

This study is the first to compare hearing results and complications between CO2 fiber laser and microdrill in ESS. Our results demonstrated similar functional outcomes between the two groups, confirming ESS as safe and effective, regardless of the technique used.

Factors affecting the incidence of chorda tympani nerve transection in middle ear surgery

Objective

To reveal the factors affecting the incidence of chorda tympani nerve (CTN) transection during middle ear surgery.

Study Design

Retrospective case review.

Setting

Tertiary referral center.

Patients

We analyzed 232 ears (117 ears with cholesteatoma, 101 ears with chronic otitis media, and 14 ears with otosclerosis) that underwent tympanoplasty or stapes surgery during 2017-2020.

Intervention

Eighty-four ears underwent transcanal endoscopic ear surgery (TEES), 103 ears underwent microscopic ear surgery (MES), and 45 ears underwent surgery using both endoscopy and microscopy (Dual).

Main Outcome Measure

To confirm CTN transection, intraoperative endoscopic/microscopic video images were evaluated. We used the same video images to determine the anatomical variation of the CTN course in the middle ear.

Results

In 18 ears (7.8%: 6/84 TEES ears [7.1%], 6/103 MES ears [5.8%], and 6/45 Dual ears [13.3%]), the CTN was cut during middle ear surgery. There was no significant difference in CTN transection among groups. In cholesteatoma patients, stapes involvement resulted in a significantly higher CTN transection incidence. CTN anatomical variants such as the "Attached Short type" and "Ultrashort type" showed a significantly higher CTN transection incidence.

Conclusion

Although endoscopic surgery did not reduce the incidence of CTN transection during middle ear surgery, pathological involvement of the stapes and CTN anatomical variants, such as the "Attached Short type" and "Ultrashort type," may increase this incidence. Preoperative evaluation of stapes involvement and anatomical location of the CTN course could help identify patients at greater risk for iatrogenic CTN transection.

Level of Evidence

4.

Radiological Evaluation of Tympanic Segment of Chorda Tympani Nerve in Normal Ears: An Ultra-High-Resolution CT Study

BACKGROUND

To visualize the course of the tympanic segment of chorda tympani nerve (CTN) using ultra-high-resolution computed tomography (U-HRCT).

METHODS

A hundred and fourteen ears with no evident otologic pathologies were included. The tympanic segment of CTN was divided into four portions: periannular, posteromalleal, malleal, and anteromalleal. The length of the periannular portion running along the tympanic annulus was recorded. Four points of interest (the beginning and end of the posteromalleal and anteromalleal portions) were selected to perform distance measurements relative to the tip of the malleus manubrium. Differences in lengths and distances were compared in terms of ear sides and sexes.

RESULTS

The length of the periannular portion was 2.49 ± 1.16 mm. The beginning of the posteromalleal portion was located more laterally on the right side than on the left side (mean: 4.09 mm vs. 3.92 mm, P = 0.016). The end of the posteromalleal portion was located more inferiorly on the right (mean: 2.11 mm vs. 2.26 mm, P = 0.018). The beginning of the anteromalleal portion on the right was located more laterally than that on the left (mean: 2.60 mm vs. 2.45 mm, P = 0.027). The start and end of the anteromalleal portion were more posteriorly located in women than in men (both Ps < 0.001).

CONCLUSIONS

The course of the tympanic segment of normal CTN was comprehensively visualized by U-HRCT. Preoperative evaluation of the tympanic segment of CTN might be helpful in avoiding iatrogenic injury during middle ear surgery.

Consequences of Stapes Surgery on Tongue Morphological Characteristics in Narrow Band Imaging, Gustatory Function and General Sensation: A Prospective Tertiary Center Study

(1) Background: Chorda tympani (CT) manipulation during stapes surgery affects its functions. We hypothesized that this alters tongue morphology and sensory functions. (2) Methods: Patients undergoing stapes surgery were tested 1 day preoperatively, 1 and 6 months postoperatively. Narrow band imaging contact endoscopy (NBI) was used to determine the number of fungiform papillae (Npapillae) and the total score of blood vessel morphology (NBItotal). The taste was tested with taste strips. General sensation was tested with a static two-point discrimination. Tests were performed on ipsilateral and contralateral side of the tongue. (3) Results: 52 otosclerosis patients were included in the study. There was a statistically significant decrease of NBItotal (p = 0.005), Npapillae (p = 0.009), sensation of sweet (p = 0.003), salty (p = 0.035), sour (p = 0.036), and bitter taste (p = 0.013) within the test side during the follow-up. A statistically significant impact on presence of dysgeusia for sweet was found 1 month postoperatively (p < 0.005). Postoperative decrease in two-point discrimination score did not reach a statistical significance (p = 0.056). (4) Conclusions: CT manipulation affects fungiform papillae density, vascular patterns and taste sensation. The general sensation of the tongue is not influenced by CT manipulation.