Local delivery of steroids to inner ear via medical device INCAT (the Inner Ear Catheter) in partial deafness patients during cochlear implantation – preliminary results and a feasibility study

The primary aim was to assess the effectiveness and safety of three different algorithms of using steroids and inner ear catheter (INCAT) MED-EL® in partial deafness patients who underwent cochlear implantation. The secondary goal was the assessment of the impact of the depth of INCAT on hearing preservation after cochlear implantation. There were three algorithms of steroid administration: 1) methylprednisolone 62.5 mg/ml (solution), 3 patients; 2) methylprednisolone 40 mg/ml (suspension), 4 patients; 3) dexamethasone 4 mg/ml (solution), 3 patients. Pure tone audiometry (0.125–8 kHz) was performed preoperatively, 1 and 6 months post-op. Hearing preservation was assessed according to the HEARRING group formula. Impedance measurements were taken at two days, 1 and 6 months after surgery. Patients treated with methylprednisolone 40 mg/ml in suspension showed the best hearing preservation (50% complete and 50% partial preservation) 1 month post-op and later remained the most favorable. The lowest impedance was found in this group both 1 and 6 months post-op. A shorter INCAT insertion depth appeared to be more favorable than a longer one. Our results suggest that patients treated with methylprednisolone 40 mg/ml (suspension) had better hearing outcomes compared to the other two medications.