Analysis of Stereotactic Accuracy of the Cosman-Robert-Wells Frame and Nexframe Frameless Systems in Deep Brain Stimulation Surgery

Abstract

Introduction: The primary goal of stereotactic systems in deep brain stimulation (DBS) surgery is accurate delivery of a DBS lead to a target identified on imaging. Thus, it is critical to understand the accuracy of the stereotactic systems and the factors which may be associated with a decrease in accuracy. Methods: Ninety patients underwent microelectrode recording-guided placement of 139 DBS leads by a single surgeon using the Cosman-Roberts-Wells (CRW) frame (n = 70) or a frameless skull-mounted trajectory guide (Nexframe; n = 69). The final DBS location was identified on a postoperative CT fused to the preoperative CT and MRI scans. The difference between this final location and the expected location was calculated. Results: The vector error was 2.65 mm (standard error, 0.22) for the frame and 2.78 mm (standard error, 0.25) for the frameless methods (p = 0.69). There was a gradual decline in error for both systems over time, as the vector error of the last 20 implants was 1.99 for the CRW frame and 2.04 for the Nexframe (p = 0.86). Conclusions: This study shows that the CRW frame and Nexframe frameless systems have equivalent accuracy. Furthermore, the accuracy of both techniques improved over time, from 3 mm initially to 2 mm with current techniques.

Analysis of Stereotactic Accuracy in Patients Undergoing Deep Brain Stimulation Using Nexframe and the Leksell Frame

“…They only reported absolute errors due to the small number of evaluated lead placements (10 placed leads with Nexframe). Our results in euclidean errors are in line with the results of Holloway et al [10] and Kelman et al [9], with 2.71 mm for Nexframe and 2.63 mm for the Leksell frame. With a Nexframe sample size of 78 placed leads, our study is the largest reported for this ‘frameless' method and the only large study directly comparing Nexframe with the Leksell frame.…”

“…Bjartmarz and Rehncrona [13] reported a superior accuracy of the Leksell frame with 1.2-mm (Leksell) and 2.5-mm (Nexframe) euclidean errors; however, the sample size was small, with 13 placed leads in both groups. Kelman et al [9] compared Nexframe to the Cosman-Roberts-Wells (CRW) frame and found no significant difference in euclidean errors for both techniques. They reported a 2.65-mm (CRW) euclidean error with 70 leads and a 2.78-mm (Nexframe) euclidean error with 69 placed leads.…”

“…Potential advantages of frameless functional surgery systems have been summarized in recent literature [9,10,11,12]. From the patient's perspective, not having a frame bolted to their head and the operating table will minimize discomfort and exhaustion during these lengthy awake procedures.…”

“…Previous studies on accuracy of frame-based and Nexframe systems have shown variable results [9,10,11,12,13,14]. Comparison between studies is limited due to differences in sample sizes and methods used to determine lead location.…”

Microelectrode Recording Duration and Spatial Density Constraints for Automatic Targeting of the Subthalamic Nucleus

“…Firstly, the STN target cannot always be well identified on the preoperative image [10,11,12]. Secondly, the clinical application accuracy of the various stereotactic systems is 0.1–5.0 mm [13,14,15,16,17,18], an error which approaches the dimension of the STN itself. Image fusion inaccuracies, MRI distortion and intraoperative brain shift may add to this error [19,20].…”