Newswise — Sudden sensorineural hearing loss (SSHL) is one of the few otological medical emergencies and for the five to 20 of every 100,000 Americans incurring this disorder; the sudden change in hearing over a three-day period can be devastating. The cause and treatment for SSHL remains open to debate but in the last two decades steroids have emerged as the treatment of choice for moderate-to-profound SSHL.
Recent attention has been directed towards targeting steroid therapy to the inner ear. A large body of work now exists demonstrating intratympanic steroid uptake through the round window membrane (RWM) in animal models. The best method for delivering steroids to the RWM is currently under investigation. One way is via injection through the tympanic membrane. The MicroWickTM delivers steroids through the tympanic membrane into the round window niche; a third method is via a microcatheter placed into the round window niche.
The existing data on intratympanic therapy is restricted due to small patient size and limited clinical studies. A duo of restive is to add to the current small body of data on this topic, by evaluating if high-dose steroid delivered at the round window membrane via these devices can improve the hearing result after failure of conventional therapy.
The authors of "Intratympanic Steroid Perfusion for Refractory Sudden Sensorineural Hearing Loss," are Sam J. Marzo MD, and Brian D. Herr MD, both at the Loyola University Medical Center, Maywood, IL. Their findings were presented September 24, 2003, at the American Academy of Otolaryngology-Head and Neck Surgery Foundation www.entnet.org Annual Meeting and OTO EXPO, being held September 21-24, 2003, at the Orange County Convention Center, Orlando, FL.
Methodology: This retrospective case review evaluated the efficacy and safety of intratympanic steroid therapy via a microwick and/or round window catheter. Patients involved in the study met the following inclusion criteria: (a) a diagnosis of SSHL, defined as >20 dB of hearing loss developing within 72 hours; (b) no improvement in hearing following treatment with high-dose systemic steroids or an existing contraindication to systemic steroid therapy. Most patients involved in the study received their conventional therapy at an outside institution and were referred for further treatment options. All patients underwent full otolaryngologic history and physical exam, routine audiologic evaluation, and magnetic resonance imaging to rule out retrocochlear pathology.
MicroWickTM placement was accomplished in the office under local anesthesia. A tympanostomy is made in the posterior inferior quadrant and a PET is placed in position to view the round window niche. The MicroWickTM is then placed through the PET resting in the round window niche. The patient returns home with instructions to administer 3 drops of Dexamethasone (mg/ml) bid until follow up in one week. Placement of the round window catheter is accomplished in the operating room under general anesthesia. A preloaded micro infusion pump perfusing Solu-Medrol (62.5 mg/ml) at a rate of 10 microliters/hour is then attached. Perfusion was continued for 10 days and the catheter was removed in the office.
Two treatment groups were developed. Earlier patients underwent immediate placement of the round window catheter following failure of conventional therapy. Recent patients underwent placement of the MicroWickTM and if no improvement in hearing resulted, proceeded with round window catheter placement.
Hearing results were evaluated based on three frequency (0.5, 1, 2 kHz) pure tone average (PTA) and speech discrimination scores (SDS). A significant hearing improvement was defined as a decrease in PTA (pure tone average, the average in decibels of the thresholds for pure tones at 500, 1000, and 2000 Hz) by 10 dB or more, or an increase in SDS (speech discrimination scores) by 20 percent.
Results: Nineteen patients (seven women, 12 men) were treated with intratympanic steroid perfusion. The average age was 55 years, ranging from 30 years to 78 years. The key findings were:
"¢ Overall, nine patients (47%) showed significant improvement in hearing following intratympanic steroid perfusion."¢ Overall, 7 patients (37 percent) demonstrated improvement in their PTA. Four patients demonstrated improvement in their speech discrimination. "¢ The average time elapsed between onset of symptoms and intratympanic therapy was six weeks, ranging from two to 20 weeks (if the patient whose interval of 20 weeks is removed, the average time interval drops to 5.2 weeks). Patients who responded to intratympanic therapy had an average time to therapy of 4.7 weeks, ranging from two weeks to 11 weeks.
No significant correlation was noted between outcome and age. The average age for patients who improved was 55 years, compared to 53 years for those who did not improve. No differences in outcomes were noted for gender or type of steroid perfused.
Conclusions: The researchers view the 47 percent response rate in patients with sudden sensorineural hearing loss refractory to conventional systemic corticosteroids as encouraging. However, the relatively small patient numbers undergoing microcatheter placement for steroid perfusion, coupled with the paucity of clinical studies in this area, lead to a recommendation of intratympanic therapy as a potential treatment option for patients with severe to profound sudden sensorineural hearing losses refractory to oral steroid therapy.
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