Intratympanic Triamcinolone Acetonide as Treatment Option for Idiopathic Sudden Sensorineural Hearing Loss

Comparison of side effects of different steroids used in intratympanic injections

OBJECTIVES

This study aimed to compare the side effects of different steroids used in the intratympanic injections (IT).

METHODS

One hundred and sixty patients diagnosed with sudden sensorineural hearing loss and undergoing IT were assigned to four groups based on the type or concentration of steroids administered (Group DM5: 5 mg/ml Dexamethasone sodium phosphate; Group DM10: 10 mg/ml Dexamethasone sodium phosphate; Group MP: 40 mg/ml Methylprednisolone sodium succinate; Group BM: 4 mg/ml Betamethasone sodium phosphate). Each group comprised 40 patients, and all participants received IT six times. The study assessed and compared the degrees and duration of pain, dizziness, and tympanic membrane damage following IT. Patients were asked to report the pain they felt using the numeric rating scale (NRS).

RESULTS

NRS scores for pain after IT showed significant differences among the four groups (p < 0.001). The average NRS scores for pain in each group were as follows: Group DM5: 1.53 ± 1.04; Group DM10: 1.45 ± 1.30; Group MP: 4.33 ± 2.22; Group BM: 6.03 ± 1.46. The durations of pain after IT also exhibited significant differences among the four groups (p < 0.001), with the longest duration observed in Group MP at 31.93 ± 15.20 min.

CONCLUSION

Different types of steroids could lead to varying degrees of pain when used in IT. Betamethasone could cause the most severe pain, and methylprednisolone could result in the longest duration of pain.

Intratympanic Triamcinolone or Dexamethasone in Sudden Sensory Neural Hearing Loss: A Randomized Clinical Trial

Sudden sensorineural hearing loss (SSNHL) is a condition in which a person experiences a rapid loss of hearing, often in one ear. The cause of SSNHL is not always clear, but it is thought to be related to issues with the inner ear, auditory nerve, or other parts of the hearing pathway. Intratympanic injection is a treatment method for SSNHL in which a medication (corticosteroids) is injected directly into the middle ear space through the tympanic membrane. This randomized clinical trial was conducted in two hospitals in Tehran, Iran. Patients with SSNHL were randomized (using the 4-block method) and included in this study. 0.5 cc of dexamethasone or triamcinolone was injected via a 25-gauge spinal needle into the cone of light of tympanic membrane. This procedure was repeated six times. In the present study, the rate of response to treatment was compared in the two groups of triamcinolone and dexamethasone, which showed that in the group where intratympanic injection of dexamethasone was performed, 70.9% of patients responded to treatment (48.4% had a complete response and 22.5% had a partial response), and in the group receiving intratympanic triamcinolone, 72.5% responded to the treatment and improved, 50% showed a complete response and 22.5% showed a partial response, and no significant difference was found in the statistical analysis of the two groups. Also, the comparison of audiometric parameters (SDS and SRT) did not show any significant difference before and after the treatment based on the treatment group, and the treatment response was found in the same group. No significant differences were noted in terms of outcome. Intratympanic dexamethasone injection was associated with a 70.9% response and triamcinolone injection with a 72.5% response.

Sustained delivery of triamcinolone acetonide from a thermosensitive microemulsion gel system for the treatment of sensorineural hearing loss

Intratympanic administration for the delivery of steroids has been extensively studied but limited because of low permeability of the drug through the row window membrane. Here, to effectively deliver poorly soluble triamcinolone acetonide (TA), microemulsions (ME) were prepared from Capmul MCM (oil), Cremophor RH40 (surfactant), and tetraglycol (cosurfactant) based on solubility studies, emulsifying ability test, and pseudoternary phase diagrams. Microemulsion gel (MEG) was prepared by mixing TA-ME with a poloxamer hydrogel base. The physicochemical properties of ME and MEG formulations were characterized, and the toxicity and oto-protective effectiveness were evaluated in vitro and in vivo. The ME-3 formulation showed a small droplet size (16.5 ± 0.2 nm), narrow PDI (0.067 ± 0.041), and enhanced TA solubility (2619.7 ± 57.6 μg/g). The optimized MEG demonstrated temperature-dependent gelation with a gelation time of 208 ± 10 sec at 37 °C. Slow degradation of the gel matrix sustained release of TA from MEG compared to the ME formulation. Both TA-ME and TA-MEG were found to be nontoxic to NIH3T3 cells at the test concentrations (0 to 5 µg/mL), and biocompatible after intratympanic administration to mice. The incorporation of ME into thermosensitive hydrogels prolonged retention of TA at the site of administration until 6 days. As a consequence, the enhanced drug absorption into the cochlea in TA-MEG group (approximately 2 times higher than other groups) protected hair cells, spiral ganglion neurons, and stria vascular cells from cisplatin-induced damage. Therefore, this injectable TA-loaded MEG is an effective and safe vehicle for the sustained delivery of triamcinolone acetonide into the inner ear.

Intratympanic Substance Distribution After Injection of Liquid and Thermosensitive Drug Carriers: An Endoscopic Study

OBJECTIVE

In the treatment of inner ear conditions, intratympanic injection emerges as an important drug delivery method. Novel compounds designed for intratympanic injection are routinely loaded in viscous drug carriers. To date, it is unclear if they can freely distribute in the middle ear. The aims of this study were to investigate the middle ear distribution of different drug carriers during intratympanic injection and to determine an optimal injection method for thermosensitive hydrogels.

METHODS

Twenty-one human temporal bones were intratympanically injected with fluid drug carriers or poloxamer-407 hydrogels at different tympanic membrane injection sites (inferior, anterior-superior) using different needle types (Whitacre, Quincke). Fluid distribution was evaluated via an endoscopic view. Injection volume, duration, backflow, and overall safety were analyzed.

RESULTS

Liquid drug carriers distribute effortlessly in the middle ear, whereas an additional ventilation hole is advantageous when applying thermosensitive hydrogels. The round window is coated with required volumes between 150 and 200 μl, irrespective of the injection position. Required volumes to also coat the stapedial footplate ranged from 310 to 440 μl. Use of the Whitacre-type needle reduced backflow to the ear canal and enabled longer tympanic membrane visibility when no additional ventilation hole was placed.

CONCLUSION

Intratympanic injection is a safe and reliable method for the application of thermosensitive hydrogels. The round window niche is readily filled regardless of the injected formulation and injection position. Although fluid drug carriers distribute effortlessly in the middle ear, the placement of an additional ventilation hole might facilitate the application of viscous hydrogels.

Tympanic Membrane Perforation After Intratympanic Steroid Injection: A Systematic Review and Meta-analysis

OBJECTIVE

We investigated the incidence of tympanic membrane (TM) perforations induced after intratympanic steroid injection (ITSI) in patients with sudden sensorineural hearing loss (SSNHL) through a systematic review and meta-analysis.

DATA SOURCES

PubMed, Embase, and MEDLINE.

REVIEW METHODS

Primary database searches were performed, and 1901 records were identified. After removal of 1802 articles through abstract screening, the remaining 99 full-text journals were assessed for eligibility to be included in the study. Fifty-eight studies that used either ventilation tubing (VT) or tympanocentesis (TC) for ITSI were selected for analysis. The subjects were divided into VT and TC groups. The rate of TM perforation after ITSI in 2 groups, sites of ITSI, needle gauge, and influence on residual hearing were investigated.

RESULTS

The cohorts comprised patients who underwent VT (n = 257, 9.6%) and TC (n = 2415, 90.4%). The proportion of TM perforation after ITSI in each group was 0.073 (95% CI, 0.0469-0.1113) and 0.010 (95% CI, 0.0045-0.0215), respectively, which suggested that the VT group showed a significantly higher TM perforation rate than the TC group (P < .001). In the subgroup analyses, there was no significant difference in the odds ratio for the rate of TM perforation according to the injection site and needle gauge for TC. The proportion of surgical repair showed no significant difference between the 2 groups.

CONCLUSION

ITSI via VT may have a significantly higher risk of TM perforation than ITSI via TC, although those are relatively small overall. ITSI should be performed in the direction to minimize possible adverse effects.

Steroid Nomenclature in Inner Ear Therapy

: Local glucocorticosteroid ("steroid") therapy is widely used to treat the inner ears of patients with Menière's disease, idiopathic sudden sensorineural hearing loss and in combination with cochlear implants. Applied steroids have included dexamethasone, methylprednisolone, and triamcinolone. In reality, however, this is often not true and the steroid forms commonly applied are dexamethasone-phosphate, methylprednisolone-hemisuccinate, or triamcinolone-acetonide. In each case, the additional component is not a counter-ion but is covalently bound to the molecule to increase aqueous solubility or potency. These drug forms are approved for intravenous or intramuscular delivery and are used "off-label" in the ear. When given systemically, the molecular form of the drug is of minor importance as the drugs are rapidly metabolized. In contrast, when administered intratympanically, the exact form of the drug has a major influence on entry into perilymph and elimination from perilymph, which in turn influences distribution along the cochlear scalae. Dexamethasone-phosphate has completely different molecular properties to dexamethasone and has different pharmacokinetic properties entering and leaving perilymph. Molecular properties and perilymph pharmacokinetics also differ markedly for triamcinolone and triamcinolone-acetonide. Methylprednisolone-hemisuccinate has completely different molecular properties to methylprednisolone. In the ear, different steroid forms cannot therefore be regarded as equivalent in terms of pharmacokinetics or efficacy. This presents a terminology problem, where in many cases the drug stated in publications may not be the form actually administered. The lack of precision in nomenclature is a serious problem for the inner ear drug delivery field and needs to be recognized.

Intratympanic Triamcinolone Acetonide as a Salvage Treatment for Idiopathic Sudden Sensorineural Hearing Loss

INTRODUCTION

Intratympanic steroid (ITS) injections represent an increasingly used salvage treatment option for patients with idiopathic sudden sensorineural hearing loss -(ISSHL) after systemic treatment. The most effective corticosteroid for this treatment modality still remains unclear. Triamcinolone acetonide has been used for ITS treatment in various clinical settings. However, there are limited clinical data of its usage in the therapeutic management of ISSHL. The aim of this study was to determine the efficacy of intratympanic triamcinolone acetonide injections as a salvage treatment for ISSHL.

METHODS

We conducted a retrospective chart review on patients affected by ISSHL with insufficient hearing recovery after primary systemic corticosteroid therapy and who were treated with intratympanic triamcinolone acetonide as a salvage therapy between January 2014 and August 2019. The patients were divided into groups according to their degree of hearing recovery, and we evaluated potential predictors of hearing recovery. Audiometric results were then compared to historic studies using dexamethasone or methylprednisolone.

RESULTS

One-hundred and fifty-two patients received up to 3 intratympanic injections with triamcinolone acetonide at 1-week intervals. The mean hearing improvement due to ITS salvage treatment was 15.9 ± 18.9 dB. Complete hearing recovery was noted in 15 patients (9.9%), while 73 patients (48%) obtained partial recovery, and 64 patients (42.1%) had no recovery. Primary systemic treatment delay, hearing improvement by primary systemic treatment, and severity of initial hearing loss were identified as significant predictors of hearing improvement. The first of the 3 injections resulted in the greatest hearing improvement.

CONCLUSION

The use of triamcinolone acetonide in ITS salvage treatment resulted in similar hearing improvements as the use of the commonly used corticosteroids, namely, dexamethasone and methylprednisolone. Longer treatment delays, lower hearing improvement by primary systemic treatment, and higher initial hearing loss are associated with poorer prognoses of hearing recovery.

Comparison of two different intratympanic corticosteroid injection protocols as salvage treatments for idiopathic sudden sensorineural hearing loss

PURPOSE

We aimed to investigate the effect of interval length and total count of intratympanic steroid (ITS) injections in salvage treatment of patients with idiopathic sudden sensorineural hearing loss (ISSNHL).

METHODS

This retrospective case-control study included 64 patients with ISSNHL, who were treated with ITS injections as salvage therapy at a tertiary referral centre. From September 2019 to December 2020, 32 patients received up to four injections every 2-4 days (revised-protocol group). These patients were 1:1 matched to patients, who received up to three injections at 1-week intervals between January 2014 and August 2019 (initial-protocol group). Hearing outcomes of the two groups were compared.

RESULTS

Both ITS salvage treatment protocols resulted in a statistically significant hearing improvement (p < 0.05). The initial-protocol declined hearing thresholds by 12 ± 11.7 dB (p < 0.001, d = 1, P = 99%). Mean hearing function was improved by 13.4 ± 19.1 dB in the revised-protocol group [p < 0.001, d = 0.7, P = 98%]. A clinically significant hearing improvement (> 10 dB) was seen in 18 patients (58.1%) in the initial-protocol group and in 14 patients (41.9%) in the revised-protocol group. A comparison of the hearing outcomes between protocol groups revealed no statistically significant differences (p > 0.05).

CONCLUSION

These results indicate that a shorter injection interval does not lead to better hearing outcomes in ITS salvage treatment for ISSNHL. Moreover, fewer ITS injections may reduce costs, physical/mental stress of the patients and lower the risk of persistent tympanic perforations.

Comparison of the Pharmacokinetic Properties of Triamcinolone and Dexamethasone for Local Therapy of the Inner Ear

Some forms of triamcinolone may provide alternate options for local therapy of the inner ear in addition to the steroids currently in use. We compared the perilymph pharmacokinetics of triamcinolone-acetonide, triamcinolone, and dexamethasone, each delivered as crystalline suspensions to guinea pigs. Triamcinolone-acetonide is a widely used form of the drug with molecular properties that allow it to readily permeate biological barriers. When applied intratympanically triamcinolone-acetonide entered perilymph rapidly but was also found to be eliminated rapidly from perilymph. The rapid rate of elimination severely limits the apical distribution of the drug when applied locally, making it unsuitable for use in the ear. In contrast, triamcinolone, rather than triamcinolone-acetonide, is a more polar form of the molecule, with higher aqueous solubility but calculated to pass less-readily through biological boundaries. Perilymph concentrations generated with intratympanic applications of triamcinolone were comparable to those with triamcinolone-acetonide but elimination measurements showed that triamcinolone was retained in perilymph longer than triamcinolone-acetonide or dexamethasone. The slower elimination is projected to result in improved distribution of triamcinolone toward the cochlear apex, potentially allowing higher drug levels to reach the speech frequency regions of the human ear. These measurements show that triamcinolone could constitute an attractive additional treatment option for local therapy of auditory disorders.