The history of intratympanic drug therapy in otology

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 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.

Dexamethasone eardrop with grommet placement vs intratympanic steroid injection for sudden sensorineural hearing loss: A randomized prospective clinical trial

OBJECTIVES

The purpose of this study was to compare different means of intratympanic steroid delivery in the treatment of idiopathic sudden sensorineural hearing loss.

DESIGN

Prospective, multicentered, randomized controlled trial.

SETTING AND PARTICIPANTS

Fifty-six patients who fulfilled the inclusion criteria for idiopathic sudden sensorineural hearing loss who failed or were contraindicated for oral steroids were included in this study. Patients were randomly divided into 2 groups according to delivery methods: group A received 4 sections of intratympanic dexamethasone injection and group B received grommet placement with dexamethasone delivery followed by 3 sections of dexamethasone ear drop application. Self-administered paper-based questionnaires were filled out to measure subjective pain scores, vertigo, anxiety, and overall satisfaction immediately after each procedure. Hearing threshold was measured with pure tone audiogram in the follow-up.

RESULTS

There was no statistical significance detected in hearing threshold improvement between both groups (P = 0.30). Grommet placement followed by dexamethasone eardrop application demonstrated a significant difference in shorter waiting time (24 min in grommet group vs 52 min in injection group; P < 0.01); and better overall satisfaction (1.6 in grommet group vs 2.5 in injection group; P < 0.05).

CONCLUSIONS

Grommet placement followed by dexamethasone eardrop application is a good alternative for a patient indicated for intratympanic steroid, with less administrative cost, shorter waiting time, and more satisfaction.

Radiologic anatomy of the round window relevant to cochlear implantation and inner ear drug delivery

Objective

To determine anatomic relationships and variation of the round window membrane to bony surgical landmarks on computed tomography.

Study design

Retrospective imaging review.

Methods

100 temporal bone images were evaluated. Direct measurements were obtained for membrane position. Vector distances and angulation from umbo and bony annulus were calculated from image viewer software coordinates.

Results

The angle of round window membrane at junction with cochlear basal turn was (42.1 ± 8.6)°. The membrane's position relative to plane of the facial nerve through facial recess was (14.7 ± 5.2)° posterior from a reference line drawn through facial recess to carotid canal. Regarding transtympanic drug delivery, the round window membrane was directed 4.1 mm superiorly from the inferior annulus and 5.4 mm anteriorly from the posterior annulus. The round window membrane on average was angled superiorly from the inferior annulus (77.1 ± 27.9)° and slightly anteriorly from the posterior annulus (19.1 ± 11.1°). The mean distance of round window membrane from umbo was 4 mm and posteriorly rotated 30° clockwise from a perpendicular drawn from umbo to inferior annulus towards posterior annulus. Together, these measurements approximate the round window membrane in the tympanic membrane's posteroinferior quadrant.

Conclusions

These radiologic measurements demonstrate normal variations seen in round window anatomy relative to facial recess approach and bony tympanic annulus, providing a baseline to assess round window insertion for cochlear implantation and outlines anatomic factors affecting transtympanic drug delivery.

The History of Myringotomy and Grommets

The first recorded myringotomy was in 1649. Astley Cooper presented 2 papers to the Royal Society in 1801, based on his observations that myringotomy could improve hearing. Widespread inappropriate use of the procedure followed, with no benefit to patients; this led to it falling from favor for many decades. Hermann Schwartze reintroduced myringotomy later in the 19th century. It had been realized earlier that the tympanic membrane heals spontaneously, and much experimentation took place in attempting to keep the perforation open. The first described grommet was made of gold foil. Other materials were tried, including Politzer's attempts with rubber. Armstrong's vinyl tube effectively reintroduced grommets into current practice last century. There have been many eponymous variants, but the underlying principle of creating a perforation and maintaining it with a ventilation tube has remained unchanged. Recent studies have cast doubt over the long-term benefits of grommet insertion; is this the end of the third era?

A novel vehicle for local protein delivery to the inner ear: injectable and biodegradable thermosensitive hydrogel loaded with PLGA nanoparticles

Delivery of biomacromolecular drugs into the inner ear is challenging, mainly because of their inherent instability as well as physiological and anatomical barriers. Therefore, protein-friendly, hydrogel-based delivery systems following local administration are being developed for inner ear therapy. Herein, biodegradable poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) containing interferon α-2 b (IFN α-2 b) were loaded in chitosan/glycerophosphate (CS/GP)-based thermosensitive hydrogel for IFN delivery by intratympanic injection. The injectable hydrogel possessed a physiological pH and formed semi-solid gel at 37 °C, with good swelling and deswelling properties. The CS/GP hydrogel could slowly degrade as visualized by scanning electron microscopy (SEM). The presence of NPs in CS/GP gel largely influenced in vitro drug release. In the guinea pig cochlea, a 1.5- to 3-fold increase in the drug exposure time of NPs-CS/GP was found than those of the solution, NPs and IFN-loaded hydrogel. Most importantly, a prolonged residence time was attained without obvious histological changes in the inner ear. This biodegradable, injectable, and thermosensitive NPs-CS/GP system may allow longer delivery of protein drugs to the inner ear, thus may be a potential novel vehicle for inner ear therapy.

Safety of Repeated-Dose Intratympanic Injections with AM-101 in Acute Inner Ear Tinnitus

Objective

To evaluate the safety and tolerability of repeated intratympanic administration of the gel-formulated NMDA receptor antagonist AM-101 in acute patients with inner ear tinnitus.

Study Design

Prospective, double-blind, randomized, placebo-controlled study.

Setting

Sixty-nine secondary and tertiary sites in North America, Europe, and Asia.

Subjects and Methods

In total, 343 subjects with persistent acute tinnitus after traumatic cochlear injury or otitis media were randomized to receive 3 intratympanic doses of either AM-101 0.87 mg/mL or placebo over 3 to 5 days. They were followed for 84 days. The primary safety end point was the incidence of a clinically meaningful hearing deterioration from baseline to study day 35. Further safety assessments included tympanic membrane closure rates, analysis of adverse events, hematology, blood chemistry, and vital signs. In addition, data were collected on applied anesthetics and injection techniques.

Results

The treatment was well tolerated, with no intervention-related serious adverse events. The incidence of clinically meaningful hearing deterioration was low, comparable between treatment groups (P = .82 for the primary safety end point) and not different between treated and untreated ears in unilaterally treated subjects. The rate of treatment and procedure-related adverse events was similar among treatment groups. The tympanic membrane was closed in 92% of subjects within 1 week and in all subjects by study day 84. Blood values and vital signs were inconspicuous.

Conclusion

Repeated intratympanic injections of AM-101 over a 3- to 5-day period appear to be safe and well tolerated, demonstrating the ability to potentially use this delivery approach over longer time periods.

Intratympanic (IT) Therapies for Menière's Disease: Some Consensus Among the Confusion

Purpose of Review

Aminoglycosides and corticosteroids are commonly used to treat Menière's disease. Intratympanic (IT) administration of these medications allows high inner ear concentrations without significant adverse systemic effects. As a direct result, IT therapy has grown in popularity. Recent studies have compared patient outcomes between IT aminoglycosides and corticosteroids. This review summarizes these findings.

Recent Findings

Trials comparing IT corticosteroids to IT placebo or oral therapy have had conflicting results. Most recently, Lambert et al. investigated the effect of IT dexamethasone in a sustained-release formulation compared to placebo. Their findings demonstrated improvement in some secondary measures of vertigo with the sustained-release formulation.IT gentamicin is known to be effective in controlling vertigo in Menière's disease. In a recent study from 2016, Patel et al compared IT gentamicin and IT methylprednisolone in a double-blind, randomized controlled trial and identified no significant differences between the two in vertigo control.

Summary

IT injections of aminoglycosides and corticosteroids can improve vertigo control. Hearing and vestibular loss however may result with IT aminoglycosides. Corticosteroids demonstrate limited hearing loss but may not have the same efficacy in controlling vertigo. Further investigation in the etiology of Menière's disease is needed to tailor the proposed treatment to suit the disease mechanism.

The Efficacy of Adjuvant Intratympanic Steroid Treatment for Otitis Media with Effusion in Children

Introduction

 Otitis media with effusion (OME) is a leading cause of hearing impairment in children. Therefore, early and proper management is essential.

Objectives

 The objective of this research is to assess the efficacy of intratympanic (IT) steroids injection for management of otitis media with effusion (OME).

Methods

 This study involved 42 children (84 ears) with bilateral OME. We used tympanometry to confirm the childreńs middle ear effusion and pure tone audiometry to determine hearing threshold. We performed myringotomy and inserted ventilation tubes (VTs) bilaterally, followed by a steroid injection of 0.4–0.6 mL methylprednisolone (40 mg/mL) into one randomly selected middle ear. This procedure was followed by once-weekly administration of steroids (0.5 mL methylprednisolone at a concentration of 40 mg/mL) into the middle ear for three consecutive weeks.

Results

 We found recurrent OME after VT alone in nine (21.4%) ears; whereas, after VT combined with steroid administration, we found two (4.76%), with statistically significant difference. We noted tympanosclerosis postoperatively in six (12.9%) ears and in one of the injected ears (2.3%) (p = 0.0484). Otorrhea occurred in eight (19%) ears with VT alone and in three (7.1%) injected ears, with non-significant difference. The duration between VT insertion and its extrusion was 6.6 = 1.1 months for ears with VT alone and 6.95 =1.12 months in injected ears (p = 0.1541 NS).

Conclusion

 IT Steroids injection for treatment of OME is a safe and simple intervention with lower incidence of symptoms recurrence and postoperative complications. Thus, its use in management of OME is recommended.

Efficacy and safety of AM-101 in the treatment of acute inner ear tinnitus--a double-blind, randomized, placebo-controlled phase II study

Objective

To evaluate the efficacy and safety of intratympanic AM-101 in patients with persistent acute inner ear tinnitus after acute acoustic trauma, idiopathic sudden sensorineural hearing loss (ISSNHL), or acute otitis media.

Study Design

Prospective, double-blind, randomized, placebo-controlled study with follow-up visits on Days 7, 30, and 90.

Setting

Twenty-eight European sites (academic tertiary referral centers and private ENT practices).

Patients

248 patients aged 16 to 65 years.

Interventions

Three intratympanic injections of AM-101 (0.27 or 0.81 mg/ml) or placebo over 3 consecutive days.

Main Outcome Measures

Efficacy was assessed by changes in minimum masking level (MML; primary end point), loudness match, tinnitus loudness, tinnitus annoyance, and sleep difficulties on a 0 to 100 numerical rating scale, THI-12 questionnaire, and patient global impression of change. Safety was evaluated using the frequency of clinically relevant hearing deterioration and adverse events.

Results

The study overall failed to demonstrate a treatment benefit based on the change in MML. However, AM-101 0.81 mg/ml showed statistically significantly better improvement for tinnitus loudness, annoyance, sleep difficulties, and tinnitus impact in patients with tinnitus after noise trauma or otitis media. The subgroup of ISSNHL-related tinnitus patients did not show conclusive results. The study drug and I.T. injections were well tolerated.

Conclusion

The study established proof of concept for AM-101 in the treatment of tinnitus arising from cochlear glutamate excitotoxicity. Patient-reported outcomes seem to be more relevant and reliable efficacy measures for assessing treatment-related changes in tinnitus than psychoacoustic tests.

Protective role of antidiabetic drug metformin against gentamicin induced apoptosis in auditory cell line

Besides their prominent function in cellular energy metabolism, the central role of mitochondria has been focused on control of cellular death in last decades. The mitochondrial permeability transition pore (PTP) is involved in the intrinsic pathway of apoptosis via the release of cytochrome c into cytosol. Metformin, a drug widely used in the treatment of type II diabetes, has recently received attention owing to new findings regarding its effect on apoptosis through mitochondrial permeability transition and cytochrome c release. The modulation of PTP is still unknown, but calcium is certainly the most important known inducer. In the present study, the preventive effects of metformin on gentamicin ototoxicity were investigated through the changes of intracellular calcium concentrations using calcium imaging in HEI-OC1 cells. Calcium imaging traced the changes of intracellular calcium concentration after the application of 50 mM of gentamicin in both 100 uM of metformin pretreated group and non-pretreated group. These calcium reactions were compared and analyzed with the results of cell viability test, Hoechst staining, intracellular reactive oxygen species level and expression of caspase-3, and poly-ADP-ribose polymerase (PARP). Continuous increase of intracellular calcium concentration (increase of 380/340 ratio) occurred after application of 50 mM of gentamicin. However, there was no change of intracellular calcium concentration in 100 uM metformin pretreated group. Cell viability was significantly higher in 100 uM metformin pretreated group and also, metformin pretreated HEI-OC1 cells produced less ROS that gentamicin alone treated group. Gentamicin increased cleaved PARP and caspase-3, but metformin inhibited the expression of caspase-3 and cleavage of PARP. This study demonstrated that metformin prevented gentamicin induced apoptosis through the calcium modulating and ROS reducing anti-apoptotic effects.

Safety of intratympanic injection of AM-101 in patients with acute inner ear tinnitus

Effective pharmacological treatments for tinnitus have proven elusive. Emerging evidence suggests that dysregulation of cochlear N-methyl-D-aspartate (NMDA) receptors may underlie aberrant excitation of the auditory nerve, which in turn is perceived as tinnitus. The blocking of these receptors thus represents a promising therapeutic approach. In a recent phase I/II clinical trial, the safety and local tolerance of intratympanic injections of the NMDA receptor antagonist AM-101 was evaluated for the first time in humans. The results from the double-blind, randomized, placebo-controlled study show that intratympanically injected AM-101 was well tolerated by study participants, and provided the first indications of therapeutic efficacy.

Intratympanic gentamicin treatment of patients with Ménière's disease with normal hearing

Objective: Understand the safety and outcomes of intratympanic gentamicin treatment in patients with Ménière's disease with normal hearing.

Study Design: Case series with chart review.

Setting: Tertiary referral center.

Subjects and Methods: A total of 224 patients with disabling Ménière's disease treated between May 1996 and June 2007 were grouped according to the American Academy of Otolaryngology–Head and Neck Surgery (AAO-HNS) 1995 Committee on Hearing and Equilibrium staging guidelines: stage 1 (<25 dB pure-tone average [PTA]); stage 2 through 4 (>25 dB PTA). Patients underwent self-treatment with intratympanic gentamicin (10 mg/mL) three times daily for one to eight weeks. Outcome measures included pre- and post-treatment speech discrimination score (SDS), PTA, electronystagmography, vertigo relief, and statistical analysis utilizing the Pearson χ2 test.

Results: Twenty-two (88%) of 24 patients with stage 1 Ménière's disease showed unchanged or improved SDS. All 24 patients showed a mean PTA loss of 8 dB. Seventeen (71%) patients reported complete or improved vertigo control. One hundred sixteen (59%) of 200 patients with stage 2 through 4 Ménière's disease showed unchanged or improved SDS. All 200 patients showed a mean PTA loss of 11 dB. One hundred forty-eight (74%) patients reported complete or improved vertigo control.

Conclusions: Patients with stage 1 Ménière's disease appear to have similar vertigo control with better hearing preservation than patients with advanced disease when treated with low-dose intratympanic gentamicin (10 mg/mL).

Demonstration of a longitudinal concentration gradient along scala tympani by sequential sampling of perilymph from the cochlear apex

Local applications of drugs to the inner ear are increasingly being used to treat patients' inner ear disorders. Knowledge of the pharmacokinetics of drugs in the inner ear fluids is essential for a scientific basis for such treatments. When auditory function is of primary interest, the drug's kinetics in scala tympani (ST) must be established. Measurement of drug levels in ST is technically difficult because of the known contamination of perilymph samples taken from the basal cochlear turn with cerebrospinal fluid (CSF). Recently, we reported a technique in which perilymph was sampled from the cochlear apex to minimize the influence of CSF contamination (J. Neurosci. Methods, doi: 10.1016/j.jneumeth.2005.10.008 ). This technique has now been extended by taking smaller fluid samples sequentially from the cochlear apex, which can be used to quantify drug gradients along ST. The sampling and analysis methods were evaluated using an ionic marker, trimethylphenylammonium (TMPA), that was applied to the round window membrane. After loading perilymph with TMPA, 10 1-muL samples were taken from the cochlear apex. The TMPA content of the samples was consistent with the first sample containing perilymph from apical regions and the fourth or fifth sample containing perilymph from the basal turn. TMPA concentration decreased in subsequent samples, as they increasingly contained CSF that had passed through ST. Sample concentration curves were interpreted quantitatively by simulation of the experiment with a finite element model and by an automated curve-fitting method by which the apical-basal gradient was estimated. The study demonstrates that sequential apical sampling provides drug gradient data for ST perilymph while avoiding the major distortions of sample composition associated with basal turn sampling. The method can be used for any substance for which a sensitive assay is available and is therefore of high relevance for the development of preclinical and clinical strategies for local drug delivery to the inner ear.