The median age at implantation was 3 years and 5 months. Most patients were born deaf without any known etiologies. In most cases, the transmastoid facial recess approach was utilized. Cochlear obstruction was identified in four patients, all of whom lost their hearing as a result of meningitis. Perilymph/cerebello-spinal fluid gusher was observed in six patients with inner ear anomalies. The preoperative developmental quotient for the Cognitive-Adaptive Area showed significant correlation with the postoperative developmental quotient in the Language-Social Area with a correlation coefficient of 0.71.