Importance of preoperative HRCT temporal bone in the orientation of the cochlea and its relation to intra-operative difficulties in cochlear implantation - predicting the grades of difficulty.

OBJECTIVE: This study emphasizes the role of preoperative high-resolution computed tomography (HRCT) temporal bone in evaluating the variation in cochlear orientation and proposes a grading system to determine the level of intraoperative difficulties encountered. METHODS: Preoperative correlation of middle ear and inner ear structures along with the basal turn angle (BTA) was done to assess the orientation. Patients were divided into three groups depending on BTA and radiology findings. RESULTS: Group A (BTA = 55°-60°) had statistically significant (p < 0.05) correlation between middle ear to inner ear structures on HRCT, whereas group B (BTA >60°) and C (BTA <55°) had variations in the alignment of middle ear structures to their corresponding inner ear structures. CONCLUSION: The association of BTA to the correlation between middle ear and inner ear structures can determine the orientation of the cochlea. This evaluation makes the surgeon aware of intraoperative challenges and helps in surgical planning.

Cochlear Implant in cochlear Hypoplasia type 4 with Chiari Malformation- Case Report.

Cochlear hypoplasia type IV is a rare cochlear malformation with hypoplastic middle and apical turns while basal turn develops normally, it often coexist with other genetic mutations. We present a case of 4 year old with chiari malformation type 1 along with bilateral Cochlear hypoplasia type IV who underwent cochlear implantation.

Cochlear implantation in children with congenital inner ear malformations - Our experience.

OBJECTIVE: To share our experience of the surgical challenges faced in cochlear implanted patients with inner ear malformation and to assess the auditory and speech perception outcomes. MATERIAL AND METHOD: Clinical records of 502 cochlear implant procedures were reviewed and data of 122 patients who had inner ear malformations were enrolled in the study. Their auditory and speech performances were evaluated post implantation for 3 years. RESULT: Cerebrospinal fluid gusher was encountered during opening of cochlea in 42 patients (34.4%) and one patient was re-explored within 24 h. In 30.3% of cases facial anomaly was found. Significant improvement in average performance was seen in all malformation types except in cochlear hypoplasia at 12 months postoperatively. CONCLUSION: Surgical challenges can be overcome with expertise and giving special attention to preoperative imaging. Our experience suggests that outcomes are favourable in patients with inner ear malformations too.