Voltage matrix algorithm for intraoperative detection of cochlear implant electrode misplacement.

Objective To develop an algorithm, based on the voltage matrix, for detecting regular cochlear implant (CI) electrode position during the implantation procedure, tip fold-over or basal kinking for lateral-wall electrodes. The availability of an algorithm would be valuable in clinical routine, as incorrect positioning of the electrode array can potentially be recognized intraoperatively. Design In this retrospective study intraoperative voltage matrix and postoperative digital volume tomography of 525 CI recipients were analyzed. On the basis of these data an algorithm was developed for detecting various kinds of electrode misplacements. Results Seven incorrect electrode positions, three tip fold (0.57%) and four basal kinking (0.76%) were detected. For detecting correct positioning, a sensitivity of 99.6%, a specificity of 83.3% and a positive predictive value (PPV) of 99.8% were found. For detecting tip fold-over a sensitivity of 100%, a specificity of 99.8% and a PPV of 75% were found. For detecting basal kinking, a sensitivity of 66%, a specificity of 99.8% and a PPV of 66% were determined. Conclusion The algorithm was found to be an effective screening tool for detecting tip fold-over or basal kinking.