Minimally Invasive MicroWick Treatment

The ideal surgical treatment should be minimally invasive, require no more than local anesthesia, and have low chances of side effects, such as hearing loss. In response to these goals, a minimally invasive procedure involving perfusion of the inner ear with medications has been extensively researched, becoming the most popular surgical treatment of Meniere’s disease over the past decade. The goal of the procedure is to treat the affected ear with a drug toxic to the vestibular (balance) system to induce a complete vestibular deficit on the treated side while minimizing hearing loss. If this goal is achieved, the elimination of the fluctuating vestibular inputs from the diseased inner ear to the brain eliminates associated feelings of vertigo, thus allowing the opposite ear to take over for balance. The advantages of placing medications directly into the inner ear include: 1) the diseased ear is treated directly without affecting the entire body; 2) a higher inner ear concentration of medication can be obtained; and 3) general body side effects of the drug are prevented.

A new technique to perfuse the inner ear involves use of endoscopes and the Silverstein MicroWick, a medication delivery device approved by the FDA in 1999. Dr. Jackson has extensively researched the applications and results of the MicroWick, resulting in numerous publications and several chapters in his recently published book on minimally invasive ear surgery. The MicroWick is a sponge-like device that allows direct and precise delivery of medication to the round window membrane, which separates the middle and inner ear. When the patient self-administers the medication into the ear canal, the MicroWick absorbs the medication and transports it to the round window membrane where it perfuses directly into the inner ear fluids. This method is similar to the current concept of self-treatment for eye disease using medicated eye drops.

The MicroWick placement procedure can be performed in the office using local anesthesia, thus avoiding the inconvenience, time, and cost of an operating room. As a first step, a small 2 mm hole is created in the eardrum overlying the round window membrane. The middle ear is examined with an endoscope to determine if there are any obstructing membranes over the round window which might prevent the instilled medications from reaching the inner ear. Any such membranes are removed if present. A small ventilation tube is inserted into the eardrum opening, and the MicroWick is placed. The MicroWick is saturated with the drug Gentamicin, allowing delivery of a high concentration of medication to the round window membrane for perfusion into the inner ear fluids. Patients are directed to self-administer medication from an ear dropper bottle into the ear three times daily.

At the end of each treatment week, hearing and vestibular/balance testing are completed, followed by a visit with the physician. The usual length of treatment is 2-4 weeks. When the physician deems appropriate, the MicroWick and tube are removed in the office and the treatment is complete.

As indicated in our studies and publications, of 92 patients with Meniere’s disease who used the MicroWick to self-treat the inner ear with Gentamicin, vertigo symptoms were relieved in 85% of the patients. Pressure in the ear was relieved or improved in 67%, while tinnitus was relieved or improved in 57% of patients. While 36% of patients experienced progression of their hearing loss in the treated ear, the majority was not bothered by the worsened hearing as long as the vertigo was relieved. In summary, this new technique of patient self-treatment using the MicroWick to deliver medications to the inner ear is minimally invasive, inexpensive, safe, effective, and well tolerated for treating Meniere’s disease and other inner ear conditions.