Subthalamic nucleus deep brain stimulator placement using high-field interventional magnetic resonance imaging and a skull-mounted aiming device: technique and application accuracy

Abstract

Object The authors discuss their method for placement of deep brain stimulation (DBS) electrodes using interventional MR (iMR) imaging and report on the accuracy of the technique, its initial clinical efficacy, and associated complications in a consecutive series of subthalamic nucleus (STN) DBS implants to treat Parkinson disease (PD). Methods A skull-mounted aiming device (Medtronic NexFrame) was used in conjunction with real-time MR imaging (Philips Intera 1.5T). Preoperative imaging, DBS implantation, and postimplantation MR imaging were integrated into a single procedure performed with the patient in a state of general anesthesia. Accuracy of implantation was assessed using 2 types of measurements: the “radial error,” defined as the scalar distance between the location of the intended target and the actual location of the guidance sheath in the axial plane 4 mm inferior to the commissures, and the “tip error,” defined as the vector distance between the expected anterior commissure–posterior commissure (AC-PC) coordinates of the permanent DBS lead tip and the actual AC-PC coordinates of the lead tip. Clinical outcome was assessed using the Unified Parkinson's Disease Rating Scale part III (UPDRS III), in the off-medication state. Results Twenty-nine patients with PD underwent iMR imaging–guided placement of 53 DBS electrodes into the STN. The mean (± SD) radial error was 1.2 ± 0.65 mm, and the mean absolute tip error was 2.2 ± 0.92 mm. The tip error was significantly smaller than for STN DBS electrodes implanted using traditional frame-based stereotaxy (3.1 ± 1.41 mm). Eighty-seven percent of leads were placed with a single brain penetration. No hematomas were visible on MR images. Two device infections occurred early in the series. In bilaterally implanted patients, the mean improvement on the UPDRS III at 9 months postimplantation was 60%. Conclusions The authors' technical approach to placement of DBS electrodes adapts the procedure to a standard configuration 1.5-T diagnostic MR imaging scanner in a radiology suite. This method simplifies DBS implantation by eliminating the use of the traditional stereotactic frame and the subsequent requirement for registration of the brain in stereotactic space and the need for physiological recording and patient cooperation. This method has improved accuracy compared with that of anatomical guidance using standard frame-based stereotaxy in conjunction with preoperative MR imaging.

Accuracy of deep brain stimulation electrode placement using intraoperative computed tomography without microelectrode recording

“…Our results (1.59 mm vector error) compare favorably with previously reported vector errors for intraoperative MRI (2.18 mm), 12 intraoperative imaging (O-arm) combined with frame-based stereotaxy (1.65 mm), 10 and conventional frame-based stereotaxy without intraoperative imaging (3 mm).…”

“…Starr et al previously reported on the correlation of the vector error and coronal approach angle, where the increased obliquity of the angle caused a higher positional error at the electrode tip. 12 A negative correlation was found between the distance of the electrode from the ventricle and both the vector error and trajectory deviation-in other words, both the vector error and the trajectory deviation were higher (less accuracy) when the electrode trajectory was closer to the ventricle. The strongest correlation was between the deviation error (radial displacement) and the distance from the ventricle in the range of 0-4 mm.…”

Surgical implantation of STN-DBS leads using intraoperative MRI guidance: technique, accuracy, and clinical benefit at 1-year follow-up

“…Thus, this opened the way to the direct targeting technique. Indeed, the improvement of MRI sequences allowed to better delineate the shape of the STN and many groups started to describe direct targeting of the STN based solely on direct visualization of it [5,19,24]. As the coordinates of optimal target within the STN was reported by many groups, it appears that direct implantation of the lead based only on the anatomo-clinical definition of the target was a reasonable strategy, whereas some authors still used peri-operatory stimulation performed on the final lead (macro stimulation) to check the threshold of side effects.…”

“…Several attempts to improve the surgical technique have been described recently, leading to Bframeless^techniques [11] or to BMRI-verifiedB techniques [22][23][24]26].…”

“…However, combining high-quality definition of the STN using intraoperative MRI obtained under general anesthesia with the possibility to reduce errors due to co-registration of several set of images in the same stereotactic space, and to monitor lead progression during surgical insertion while checking the absence of surgical complication is an appealing method that has recently been developed by the group from the University of California San Francisco (UCSF) [22,24].…”