Multiple studies have shown that intratympanic (IT) drug therapy can be safe and effective for treating idiopathic sudden sensorineural hearing loss (ISSNHL) in adults. However, beyond those broad outcomes, the literature gets a bit opaque. Among the management issues that lack consensus among researchers are optimal patient selection, the best dosage and duration of therapy and the most effective drugs to use. And, while new ISSNHL treatment guidelines have shed some light on the role IT drug therapy should play in treating the condition, questions—and controversies—still remain.
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January 2013To gain more insight into how clinicians can interpret these results and use IT drug therapy optimally in their ISSHNL patients, ENTtoday spoke with several leading experts, including Richard K. Gurgel, MD, assistant professor in the division of otolaryngology-head and neck surgery at the University of Utah Health Care in Salt Lake City, who has extensive practice experience offering IT drug therapy to his patients with the disorder.
To best understand how and why IT drugs work, it is necessary to realize that “the term ‘intratympanic’ is something of a misnomer because it only describes the route of administration,” Dr. Gurgel told ENTtoday. “What we’re really accomplishing with this modality is inner-ear perfusion of medications into the inner ear via the transtympanic route.”
Before the advent of this approach, “there was no reliable method for altering the pathophysiology of the inner ear without destroying it or obliterating its normal function,” he said. With IT drug therapy, medication can be injected into the middle ear space, where it then travels by diffusion into the inner ear and acts upon structures that govern hearing. “This really is a very elegant, compelling modality,” Dr. Gurgel said, adding that it also has rigorous science to support it. In one study, researchers found that perilymph steroid concentrations were significantly higher after IT steroid therapy than after systemic steroid administration (Laryngoscope. 1999;109(7, Pt 2):1-17).
Impact on Disease
In reviewing the literature on the impact IT drug therapy has on actual disease, a less clear picture emerges, said Dr. Gurgel. “Most clinical studies are retrospective, single-institution studies with small patient numbers lacking adequate controls. The design, outcome measures and efficacy results of most studies tend to be all over the map.”
But there are some studies that do offer some useful insights, he added. He pointed to a 2011 study by Rauch and colleagues published in JAMA that he feels is one of the best-designed trials of its type. The prospective, randomized study compared oral versus IT steroid therapy for ISSNHL and found that both modalities were equivalent in the amount of improvement they achieved in final pure tone average (PTA), word recognition scores and other key measurements of hearing recovery (2011;305:2071-2079).