Directional DBS leads show large deviations from their intended implantation orientation

Objective: Lead orientation is a new degree of freedom with directional deep brain stimulation (DBS) leads. We investigated how prevalent deviations from the intended implantation direction are in a large patient cohort. Methods: The Directional Orientation Detection (DiODe) algorithm to determine lead orientation from postoperative CT scans was implemented into the open-source Lead-DBS toolbox. Lead orientation was analyzed in 100 consecutive patients (198 leads). Different anatomical targets and intraoperative setups were compared. Results: Deviations of up to 90 degrees from the intended implantation direction were observed. Deviations of more than 30 degrees were seen in 42% of the leads and deviations of more than 60 degrees in about 11% of the leads. Deviations were independent from the neuroanatomical target and the stereotactic frame but increased depending on which microdrive was used. Discussion: Our results indicate that large deviations from the intended implantation direction are a common phenomenon in directional leads. Postoperative determination of lead orientation is thus mandatory for investigating directional DBS.