Hyaluronan applied to lesioned round window membrane is free from cochlear ototoxicity

A randomized controlled trial to test the efficacy of trans-tympanic injections of a sodium thiosulfate gel to prevent cisplatin-induced ototoxicity in patients with head and neck cancer

Background

Cisplatin-induced hearing loss is frequent and severe. Antioxidants such as sodium thiosulfate (STS) can neutralize the effects of cisplatin. The objective of the trial was to test the efficacy of trans-tympanic injections of a STS gel to prevent cisplatin-induced ototoxicity.

Methods

Eligible participants were newly diagnosed patients with stage III or IV squamous cell carcinoma of the mouth, oropharynx, hypopharynx, or larynx and scheduled to be treated by concurrent chemoradiation (CCR). Patients with asymmetric hearing were not eligible. The planed treatment included cisplatin 100 mg/m² at days 1, 22 and 43. A baseline pre-treatment complete audiometric evaluation (pure tone at frequencies ranging from 0.5 to 14 kHz, bone conduction at 0.5–4 kHz and DPOAEs) was performed. Adverse effects were noted according to CTCAE.

On the day before the beginning of CCR, eligible and consenting patients were randomized to receive a trans-tympanic injection of the gel either in the left ear or in the right ear. A final post-treatment complete audiometric evaluation was scheduled to be performed 1 month after the end of CCR by audiologists kept blind to the ear assignment.

For the main outcome, the permanent threshold shift (PTS) in decibel (dB) was calculated as the difference between the final and baseline measures at all pure tone frequencies at 0.5–14 kHz for each patient and for each ear. The main outcome was assessed blindly in a mixed linear model with the PTS as the dependent variable and intervention, frequency, their interaction and radiation dose to the cochlea as independent variables.

Results

Between January 2015 and April 2016, 13 patients were randomized. The trial was stopped in June 2016 for poor accrual. The average loss of hearing over all frequencies was 1.3 dB less for treated ears compared to control ears. Although not statistically (p = 0.61) nor clinically significant, the difference was in favor of the treated ears for all frequencies between 3 and 10 kHz.

Conclusions

Our trial suggests that STS deposited on the round window was safe for the middle and inner ears. More work is needed to improve the efficacy of trans-tympanic injections of cisplatin antidotes.

Trial registration

ClinicalTrials.gov, NTC02281006, Registered 3 November 2014.

Hyaluronate Gel Stapedotomy

OBJECTIVE: To evaluate hearing results and postoperative dizziness after stapedotomy with application of sodium hyaluronate gel (HG) to the oval window niche during fenestration of the footplate.

STUDY DESIGN: Case-control study comparing 27 stapedotomies with HG and 32 stapedotomies without HG.

OUTCOME MEASURE: Preoperative and postoperative audiometric data, postoperative dizziness (vertigo or dysequilibrium), and nystagmus.

RESULTS: Postoperative hearing results were not statistically different for the 2 groups. There were no cases of postoperative sensorineural hearing loss greater than 10 dB. Early postoperative dizziness (χ2 = 4.08, P = 0.043) and nystagmus (χ2 = 5.05, P = 0.024) were reduced in the HG group.

CONCLUSIONS: HG stapedotomy is safe and effective and results in less early postoperative dizziness and nystagmus when compared with the standard technique of stapedotomy. The application of HG to the oval window niche to prevent blood from entering or perilymph from escaping the vestibule during fenestration of the stapes footplate may contribute to a quicker recovery in outpatient otosclerosis surgery.

EBM rating: B-3b

Local treatment of the inner ear: a study of three different polymers aimed for middle ear administration

CONCLUSION

A formulation based on sodium hyaluronate (NaHYA) was the most promising candidate vehicle for intra-tympanic drug administration regarding conductive hearing loss, inflammatory reactions, and elimination.

OBJECTIVES

Recent advances in inner ear research support the idea of using the middle ear cavity for drug administration to target the inner ear. This paper presents rheological and safety assessments of three candidate polymer formulations for intra-tympanic drug administration.

METHOD

The formulations were based on sodium carboxymethyl cellulose (NaCMC), sodium hyaluronate (NaHYA), and poloxamer 407 (POL). Rheological studies were performed with a controlled rate instrument of the couette type. Safety studies were performed in guinea pigs subjected to an intra-tympanic injection of the formulations. Hearing function was explored with ABR before and 1, 2, and 3 weeks after the injection. Elimination of the formulations marked with coal was explored with an endoscopic digital camera 1, 2, and 3 weeks after injection. Middle and inner ear morphology was examined with light microscopy 6 days after injection.

RESULTS

The results speak in favor of NaHYA, since it did not cause prolonged hearing threshold elevations. The results of the elimination and morphological investigations support the conclusion of NaHYA being the most promising candidate for intra-tympanic administration.

Prevention of cisplatin-induced hearing loss by administration of a thiosulfate-containing gel to the middle ear in a guinea pig model

PURPOSE

Thiosulfate may reduce cisplatin-induced ototoxicity, most likely by relieving oxidative stress and by forming inactive platinum complexes. This study aimed to determine the concentration and protective effect of thiosulfate in the cochlea after application of a thiosulfate-containing high viscosity formulation of sodium hyaluronan (HYA gel) to the middle ear prior to i.v. injection of cisplatin in a guinea pig model.

METHODS

The release of thiosulfate (0.1 M) from HYA gel (0.5% w/w) was explored in vitro. Thiosulfate in the scala tympani perilymph of the cochlea 1 and 3 h after application of thiosulfate in HYA gel to the middle ear was quantified with HPLC and fluorescence detection. Thiosulfate in blood and CSF was also explored. The potential otoprotective effect was evaluated by hair cell count after treatment with thiosulfate in HYA gel applied to the middle ear 3 h prior to cisplatin injection (8 mg/kg b.w.).

RESULTS

HYA did not impede the release of thiosulfate. Middle ear administration of thiosulfate in HYA gel gave high concentrations in the scala tympani perilymph while maintaining low levels in blood, and it protected against cisplatin-induced hair cell loss.

CONCLUSION

HYA gel is an effective vehicle for administration of thiosulfate to the middle ear. Local application of a thiosulfate-containing HYA gel reduces the ototoxicity of cisplatin most likely without compromising its antineoplastic effect. This provides a minimally invasive protective treatment that can easily be repeated if necessary.

Intratympanic dexamethasone with hyaluronic acid in the treatment of idiopathic sudden sensorineural hearing loss after failure of intravenous steroid and vasoactive therapy

The purpose of this prospective study was to test whether intratympanic application of dexamethasone/hyaluronic acid improves hearing outcome in patients with pantonal idiopathic sudden sensorineural hearing loss (ISSHL), in patients with sudden deafness or sudden profound SHL and in patients with predominant high-frequency ISSHL who are refractory to intravenous steroid and vasoactive therapy. The study took place in an academic tertiary referral hospital involving 21 patients with pantonal ISSHL, 10 patients with sudden deafness or sudden profound SHL and 9 patients with a high-frequency ISSHL. Intratympanic dexamethasone/hyaluronic acid was administered in the affected ear. Hearing was evaluated by means of standard pure-tone audiometry. The differences between pure-tone hearing thresholds by air conduction before intravenous therapy and before the beginning of the intratympanic therapy, as well as before and after intratympanic therapy, were calculated. Statistical analysis was performed by means of the Wilcoxon's test for paired samples. Intratympanic injection of dexamethasone/hyaluronic acid results in a significant global (pantonal) improvement in hearing in patients with pantonal ISSHL. It also effects improvement in hearing at selected frequencies (namely at 1.5 and 3 kHz) in patients with a predominant high-frequency ISSHL and at selected frequencies (namely at 0.5, 0.75 and 1 kHz) in patients with sudden deafness or sudden profound SHL. Neither systemic nor local side effects were observed. Intratympanic administration of dexamethasone/hyaluronic acid provides a safe and efficacious therapeutic option for the treatment of patients with pantonal and high-frequency ISSHL who don't respond to intravenous steroid and vasoactive therapy.

Effect of topical hyaluronic acid on experimental cholesteatoma

PURPOSE

Inflammation and connective tissue hyperplasia are believed to be important etiological factors in cholesteatoma pathogenesis. Previous work has shown that topically applied hyaluronic acid can reduce connective tissue proliferation in healing wounds and accelerate healing of tympanic membrane perforations. This study was undertaken to determine whether the antiproliferative effect of hyaluronic acid may inhibit propylene glycol-induced cholesteatoma in an animal model.

MATERIALS AND METHODS

A 60% propylene glycol solution was injected bilaterally into the middle ear cavities of 20 adult chinchillas. The control group (N = 10) received propylene glycol alone. In addition to propylene glycol injections, the experimental group (N = 10) received repeated bilateral topical applications of 1.5% hyaluronic acid onto the tympanic membranes. Animals were killed at 4 weeks for gross and light microscopic examination.

RESULTS

Seven control and 10 experimental animals survived the full 1-month study period. At the end of that time, cholesteatoma was found in 71% (10/14) of control ears and 70% (14/20) of experimental ears. Tympanic membrane structure did not differ significantly between groups by light microscopy and, in all animals, cholesteatomas originated by migration of hyperplastic epidermis through the tympanic membrane, as has been observed in previous studies using this animal model.

CONCLUSION

Under the conditions of this study, topical hyaluronic acid had no significant effect on cholesteatoma formation.