Standardization of Outcome Measures for Intratympanic Steroid Treatment for Idiopathic Sudden Sensorineural Hearing Loss

Intratympanic Gels for Inner Ear Disorders: A Scoping Review of Clinical Trials

OBJECTIVE

Intratympanic injections are a safe, well tolerated procedure routinely performed by ENT's specialists. Intratympanic injections of gels have the potential to deliver therapeutics into the cochlea through the round window membrane prolonging the release of drugs in the inner ear compartment. Aim of the present review is to summarize clinical trials testing pharmacological treatments for inner ear pathologies through intratympanic gel formulations.

DATA SOURCES

Online databases (Google scholar and PubMed) and registers (Clinicaltrials.gov and Euclinicaltrial) were used to identify clinical trials performed between 1990 and 2022.

REVIEW METHODS

PRISMA criteria have been followed. Clinical trials testing gel formulations administered through local intratympanic injections and targeting inner ear disorders were included. All the reports were identified by the authors working in pairs sequentially selecting only studies respecting the inclusion criteria.

RESULTS

A total of 45 clinical studies have been noticed; the gels for intratympanic injection are in the form of poloxamers or hyaluronic acid combinations; the trials found target different kind of inner ear disorders: acquired-stable SNHL, tinnitus, acute sudden SNHL, Meniere disease, cisplatin induced ototoxicity and hearing preservation in patients undergoing cochlear implant surgery.

CONCLUSION

Few studies listed do not provide the specific kind of gel formulation used but only report the intratympanic delivery vehicle as "gel" or "thermogel". Multiple clinical studies have been targeting several forms of inner ear disorders by injecting different compounds through poloxamer and hyaluronic acid formulations. Larger and more advanced clinical stages are necessary to confirm the efficacy of these chemical compounds.

Clinical efficacy of intratympanic steroid injection for treating idiopathic sudden sensorineural hearing loss

BACKGROUND

Idiopathic sudden sensorineural hearing loss (ISSNHL) is an emergency that causes permanent hearing loss if timely treatment is not provided. However, the evidence supporting the effect of intratympanic steroid injection (ITSI) starting time on hearing outcome is limited.

METHODS

We retrospectively enrolled 582 patients with ISSNHL who were treated with ITSIs and reviewed their clinical and audiological variables. The relationship between ITSI starting time and hearing recovery was analyzed.

RESULTS

The mean starting time of ITSI was 13.17 ± 16.53 days. The overall hearing recovery rate was 55.15% (recovery = mean hearing level gain of ≥10 dB). The recovery rates were 79.2%, 67.4%, 50%, 36.6%, and 17.8% for the ITSI starting times of 1 to 3, 4 to 7, 8 to 14, 15 to 28, and ≥29 days, respectively. A multivariate analysis revealed that ITST starting time (odds ratio [OR] = 0.94, 95% CI, 0.92-0.96, p < 0.001) and salvage therapy (OR = 0.55, 95% CI, 0.35-0.86, p = 0.009) were independent poor prognostic factors for patients with ISSNHL.

CONCLUSION

Earlier ITSI treatment is associated with a higher hearing recovery rate. Comorbidities and post-ITSI complications were nonsignificant independent risk factors.

Comparison of Intratympanic Steroid and Hyperbaric Oxygen Salvage Therapy Hearing Outcomes in Idiopathic Sudden Sensorineural Hearing Loss: A Retrospective Study

OBJECTIVES

Systemic steroids are the most common first-line therapy in sudden sensorineural hearing loss (SSNHL), with significant improvement in hearing outcomes in over 60% of patients. It is unknown why 40% of patients do not respond to systemic steroid therapy. Salvage treatment includes intratympanic steroids (ITS) and hyperbaric oxygenation (HBO) therapy, with inconsistent results reported. This study aimed to compare the results of ITS and HBO therapy in patients with SSNHL that previously failed systemic steroid therapy.

DESIGN

This is a comparative retrospective nonrandomized interventional cohort study, enrolling 126 patients with SSNHL. Out of these, 35 patients received HBO therapy, 43 patients received ITS, and 48 patients did not receive any second-line therapy (control group). Pure-tone audiograms were performed before and after the salvage therapy in the IT and HBO groups and at the same time interval in the control group. Study variables included age, time until therapy initiation, tinnitus status, and hearing outcomes, with a cutoff criteria of cumulative >30 dB improvement on all frequencies indicating recovery.

RESULTS

ITS and HBO therapy were associated with statistically significant hearing recovery at all frequencies compared to systemic steroids. The results show an average hearing improvement of 13.6 dB overall frequencies (250 to 8000 Hz) after ITS therapy and 7.4 dB in HBO therapy in comparison to the control group. Presence of significant hearing improvement positively correlated with age, ITS therapy, and HBO therapy. Presence of tinnitus before therapy was negatively correlated with hearing improvement. Patients with tinnitus present at the start of therapy improve 4.67 dB less on average compared to those without tinnitus. ITS therapy significantly reduced tinnitus compared to the other two treatment options. Patients with tinnitus present before therapy significantly improve hearing at low frequencies, compared to the control group.

CONCLUSIONS

ITS and HBO therapy show superior hearing results compared to observation alone after failed oral steroid therapy for SSNHL. ITS shows an additional positive impact on tinnitus reduction and shows superior hearing outcomes after salvage therapy.