Can an operation of deaf ear be dangerous for hearing?

Evaluation of inner ear damage by mastoid drilling with measurement of serum prestin (SLC26A5) levels

OBJECTIVE

The objective of this study is to demonstrate any inner ear injury caused by drilling in mastoid surgery with prestin, outer hair cell motor protein specific to the cochlea.

METHODS

The patients with chronic otitis media requiring mastoidectomy (n = 21) and myringoplasty (n = 21) were included. Serum prestin level obtained from blood samples was measured before surgery and on postoperative days 0, 3, and 7 using Human Prestin (SLC26A5) ELISA Kit. All patients underwent the Pure Tone Audiometry (PTA) test before surgery and on the postoperative 7th day. The drilling time was also recorded for all patients who underwent mastoidectomy.

RESULTS

In both mastoidectomy and myringoplasty groups, the postoperative serum prestin levels increased on days 0 and 7 (pday-0 = 0.002, pday-7 = 0.001 and pday-0 = 0.005, pday-7 = 0.001, respectively). There was no significant difference in the serum prestin levels between the two groups, postoperatively. The PTA thresholds at day 7 did not change in either group. A significant decline at 2000 Hz of bone conduction hearing threshold in both groups and a decline at 4000 Hz in the myringoplasty group were found. There was no correlation between the drilling time and the increase of prestin levels in the postoperative day 0, 3, and 7.

CONCLUSION

Our results showed that mastoid drilling is not related to a significant inner ear injury. Although the myringoplasty group was not exposed to drill trauma, there was a similar increase in serum prestin levels as the mastoidectomy group. Also, a significant decline at 2000 Hz of bone conduction hearing threshold in both groups and a decline at 4000 Hz in the myringoplasty group were found. These findings suggest that suction and ossicular manipulation trauma can lead to an increase in serum prestin levels and postoperative temporary or permanent SNHL at 2000 and 4000 Hz.

LEVEL OF EVIDENCE

Level-4.

Effect of Drill Induced Noise on Contralateral Normal Ear Following Cortical Mastoidectomy

INTRODUCTION

Chronic suppurative otitis media (CSOM) is a long standing infection of the middle ear cleft. Mastoidectomy, with or without tympanoplasty, is the preferred treatment for CSOM. However, the drill used during ear surgery generates noise that may potentially cause hearing damage in both the operated and opposite inner ear, leading to temporary or permanent hearing loss.

MATERIALS AND METHODS

The study included patients diagnosed with CSOM who underwent surgeries in the Otorhinolaryngology department. Postoperatively, all patients were followed up on the 7th day and 1 month after the surgery. Pure Tone Audiometry (PTA) was performed to evaluate the hearing outcomes.

RESULTS

A total of 61 patients were included in the study. The mean preoperative PTA of contralateral ear bone conduction among the study participants was 6.48. At the 7th day post-operation, the mean post-operative PTA of contralateral ear bone conduction for the same participants was 7.77. This difference was statistically significant according to the Paired T-test (P = 0.001).However, when evaluating the mean preoperative PTA of contralateral ear bone conduction (6.48) and the mean post-operative PTA at 1st month (6.02), the difference was not statistically significant (P = 0.208).Additionally, there was no statistical difference in air conduction and air-bone gap before and after surgery.

CONCLUSION

The study suggests that mastoid drilling is associated with a significant temporary hearing loss in the contralateral ear immediately after surgery, which eventually recovers within a month. However, the hearing loss is considered negligible and not statistically significant in the long term. It is worth considering additional audiological investigations, such as otoacoustic emissions, to detect this type of hearing loss more accurately.

Complication Rates in Osteotome and Drill Techniques in External Auditory Canal Exostoses: A Systematic Review and Meta-Analysis

OBJECTIVES

To assess and compare complication rates of symptomatic external auditory canal (EAC) exostoses treated with drill versus osteotome canalplasty.

DATABASES REVIEWED

PubMed/Medline, OVID, EMBASE, Web of Science, Google Scholar.

METHODS

A systematic review and meta-analysis in accordance with PRISMA guidelines and standardized bias assessment using the JBI critical appraisal checklist was performed. Studies containing original outcome data on drill and osteotome canalplasty were included. The primary study outcome was complication rates.

RESULTS

Fifteen studies were included, encompassing 1399 total patients (1788 ears) with 530 and 1258 ears in the osteotome and drill groups, respectively. Ten studies used a drill, 2 used an osteotome, and 3 used both. The most frequently reported complications were tympanic membrane (TM) perforation (osteotome group: 5.3% [95% CI: 1.7%-10.9%]; drill group: 3.8% [1.5%-7.1%]), sensorineural hearing loss (SNHL) (0.69% [0.07%-1.9%]; 4.3% [2.2%-7.0%]), and postoperative stenosis (1.1% [0.0005%-4.3%]; 4.1% [1.9%-7.0%]). Use of the osteotome was associated with a lower rate of SNHL (P < .05) and stenosis (P < .05), and a higher rate of TM perforation (P < .05). Heterogeneity of the studies included in the analyzed complications ranged from moderate to high. Level of evidence in the included studies ranged from 2b to 4 and all studies had an overall low risk of bias.

CONCLUSION

While an osteotome technique may increase the risk of TM perforation, drill canaloplasty may increase the risk of SNHL and postoperative stenosis in EAC exostectomy. The exact quantity of hearing loss could not be definitively evaluated. Additional research with participant randomization is needed to assess clinical efficacy.

LEVEL OF EVIDENCE

Level 8.

Otolin-1, as a Potential Marker for Inner Ear Trauma after Mastoidectomy

OBJECTIVES

The aim of this prospective clinical study was to examine the negative effect of drilling by measuring peripheral Otolin-1 levels as a potential biomarker.

MATERIALS AND METHODS

Patients who underwent mastoidectomy due to chronic otitis media were included in the study. Otolin-1 levels were measured preoperatively and 6 h postoperatively, and total drilling time was noted. Preoperative serum Otolin-1 levels in 31 patients were compared with those in31 age- and sex-matched healthy individuals. Pre- and postoperative serum Otolin-1 levels were also compared.

RESULTS

Tympanoplasty was performed through canal wall-down (n=17) and wall-up mastoidectomy (n=14) in our sample. The mean duration of drilling was 52.7±13.8min. Preoperative serum Otolin-1 levels were significantly lower in patients than in healthy controls (21.0±3.0 vs. 23.5±3.9 pg/mL, p=0.006). We also found significantly higher postoperative serum Otolin-1 levels than preoperative levels (21.0±3.0 vs. 27.0±6.9 pg/mL, p<0.001). An increase in serum Otolin-1 levels during surgery was independently associated with drilling time in multivariate linear regression analysis (r=0.309, p<0.001).

CONCLUSION

A nearly postoperative increase in serum Otolin-1 levels after mastoidectomy was independently associated with drilling time. We show that serum Otolin-1 levels may be used to indicate inner ear trauma in clinical practice in the future.

Effect of Mastoid Drilling on Hearing of the Contralateral Normal Ear in Mastoidectomy

To evaluate hearing of the contralateral normal ear before and after mastoidectomy in a longitudinal manner and to assess whether the hearing loss is transient or permanent and to find out the duration of temporary hearing loss. This was a clinical longitudinal observational study involving 50 patients with unilateral chronic suppurative otitis media requiring mastoidectomy operation over a period of 18 months after satisfying the inclusion criteria. During the part of the mastoidectomy surgery involving drilling of the mastoid bone, noise levels were recorded at multiple points in the surgery using a digital sound level meter. Postoperatively, beginning from Day 1 to Day 7, PTA and OAE of the contralateral ear were recorded for all patients. The patients were then followed up at 1, 3 and 6 months postoperatively, at which times PTA and OAE were repeated. There is an increase in the absence of High Frequency DPOAEs on the first and second postoperative days, but this increase is higher than that of Low Frequency DPOAEs and gradually returns to normal by 72 h. OAEs were found to be more sensitive at diagnosing and tracking the progress of affected patients. All affected ears only had a temporary postoperative hearing loss, primarily affecting the higher frequencies and returning to normal within 72 h. Drill-generated noise and vibration during mastoidectomy operation is associated with a significant temporary shift in hearing thresholds of the contralateral normal ear in susceptible individuals, affecting the higher frequencies, and is best evaluated using DPOAEs.

Effect of drill-induced noise on hearing in non-operated ear

BACKGROUND

The aim of this study was to evaluate the effect of drill-generated noise on hearing loss in non-operated ear and if any, was temporary or persistent.

MATERIALS AND METHODS

In this prospective clinical study, 23 patients who had undergone mastoidectomy and normal contralateral hearing were enrolled. Patients were evaluated preoperatively and postoperatively (1 and 7 days) following surgery using low and high-frequency pure tone audiometry (PTA) and low and high-frequency transient evoked and distortion product otoacoustic emission (DPOAE) testing.

RESULTS

Comparing preoperative and 1-day after surgery, PTA averages were significantly different at low frequencies, but no statistical significant differences were observed at 0.25 KHz and high-frequencies. Comparing 1-day after surgery and 7 days after surgery showed that, PTA averages at 0.5, 2 and 2 KHz were significantly different with no significant differences at the other average of thresholds in low and high frequencies; PTA average at 1 KHz was significantly different with, no significant differences at the other averages of thresholds in low and high frequencies. DPOAEs showed a significant difference preoperative and 1-day after surgery, 1-day and 7 days after, but DPOAEs were not significantly different. Transiently evoked otoacoustic emissions (TEOAEs) had a significant difference preoperative and 1-day after surgery, 1-day and 7 days after but when comparing preoperative and 7 days after surgery, TEOAEs were not significantly different.

CONCLUSIONS

Drill-induced noise during ear surgery (mastoidectomy) can cause reversible changes in PTA, DPOAEs and TEOAEs in the non-operated ear.

Surgery of the ear and the lateral skull base: pitfalls and complications

Surgery of the ear and the lateral skull base is a fascinating, yet challenging field in otorhinolaryngology. A thorough knowledge of the associated complications and pitfalls is indispensable for the surgeon, not only to provide the best possible care to his patients, but also to further improve his surgical skills. Following a summary about general aspects in pre-, intra-and postoperative care of patients with disorders of the ear/lateral skull base, this article covers the most common pitfalls and complications in stapes surgery, cochlear implantation and surgery of vestibular schwannomas and jugulotympanal paragangliomas. Based on these exemplary procedures, basic "dos and don'ts" of skull base surgery are explained, which the reader can easily transfer to other disorders. Special emphasis is laid on functional aspects, such as hearing, balance and facial nerve function. Furthermore, the topics of infection, bleeding, skull base defects, quality of life and indication for revision surgery are discussed. An open communication about complications and pitfalls in ear/lateral skull base surgery among surgeons is a prerequisite for the further advancement of this fascinating field in ENT surgery. This article is meant to be a contribution to this process.