A quantitative assessment of the accuracy and reliability of O-arm images for deep brain stimulation surgery.

Background: Deep brain stimulation (DBS) surgery has an average accuracy of 2 to 3 mm (range, 0-6 mm). Intraoperative detection of track location may be useful in interpreting physiological results and thus limit the number of brain penetrations as well as decrease the incidence of reoperations. The O-arm has been used to identify the DBS lead position; however, early results have indicated a significant discrepancy with lead position on postoperative imaging.

Objective: This prospective study was conducted to determine the accuracy and reliability of fiducial and track localization and to assess the accuracy of O-arm image-based registration. The computed tomography (CT) image was considered the gold standard, and so for this study, the locations of all objects on the O-arm image were compared with their CT location.

Methods: Thirty-three DBS surgeries were performed using the O-arm to image each track with detailed analysis of fiducial and track localization accuracy. Twenty-one subsequent surgeries were performed using O-arm registration. Only the final lead position was assessed in these individuals.

Results: The measurement error of the system was 0.7 mm, with a maximum error of 1.9 mm. Twenty-two percent of the parallel tracks through the BenGun exceeded this error and demonstrated the ability of the O-arm to detect these skewed tracks. The accuracy of final lead position was 2.04 mm in procedures with registration based on an O-arm image. This was not significantly different from CT-based registration at 2.16 mm.

Conclusion: The O-arm was able to detect skewed tracks and provide registration accuracy equivalent to a CT scan.