Window of Opportunity: New time frame suggested for cochlear implant surgery in advanced otosclerosis

A new treatment algorithm for advanced otosclerosis, based on the clinical experience of Dutch investigators and supported by a literature review they conducted, suggests that the window for successful cochlear implantation (CI) in patients with severe disease is narrower than some otolaryngologists may believe (Laryngoscope. 2011;121(9):1935-1941).

According to the authors, once ossification of the middle and inner ear progresses in these patients, the surgical complications that often occur severely limit the chances for a satisfactory outcome. Given that known risk, it’s logical to at least consider performing CI surgery earlier in the disease process in such patients, rather than opting for stapes surgery or hearing aids and follow-up, according to Paul Merkus, MD, PhD, associate professor of otolaryngology and neurotology and a member of the VU University Medical Center Cochlear Implant team in Amsterdam, The Netherlands.

The algorithm divides patients into three groups based on audiometry testing: those with maximum speech determination (SD) scores of less than 30 percent, 30 percent to 50 percent and 50 percent to 70 percent. Based on two other key findings, CT scans of the middle ear and the extent of the air-bone gap (ABG), patients are treated with one of those three primary interventions (Laryngoscope. 2011;121:1935-1941).

For example, patients with SD scores of less than 30 percent often suffer from severe sensorineural hearing loss, Dr. Merkus noted. As his literature review showed, he pointed out, the most effective therapeutic intervention for these patients is CI, “because stapedotomy does not overcome the sensorineural component.”

In patients with SD scores between 30 percent and 50 percent, he added, the algorithm recommends either stapedectomy or CI, depending largely on CT scan results. If those scans show that patients have severe retrofenestral otosclerosis, “CI is the better option” because of the very favorable hearing results that can be achieved, Dr. Merkus said. If the CT scan shows less cochlear involvement, “the ABG should guide the surgeon.” If the ABG is 30 decibels or more, stapedotomy is “a cost-effective option, with good chances of improvement of hearing,” Dr. Merkus said. If the results of stapes surgery in such patients are unsatisfactory at any point in time, he noted, patients can still be treated with a CI. If the ABG is 30 db or less, CI is the preferred option because, in this group, “stapedotomy yields insufficient improvement of hearing.”

Dr. Merkus and his colleagues have already used these patient selection criteria for several years in their clinic. “It’s a bit backward in terms of how research is usually done, but we wanted to know if our approach, and the clinical successes we were having with it, was actually supported by data, so that’s why we conducted the literature search that has resulted in the algorithm in our report,” he told ENT Today.