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

Abstract

Objective: To determine and compare the accuracy of Nexframe and the Leksell stereotactic frame in deep brain stimulation (DBS) procedures. Background: The ‘frameless' Nexframe uses bone fiducials rather than a head-mounted frame, which offers potential benefits for both the patient and the surgical team. Accuracy of lead implantation and factors affecting this accuracy are of crucial importance but have not been extensively studied for the frameless system. Design/Methods: The location of 194 (Leksell frame, n = 116; Nexframe, n = 78) DBS leads was determined on postoperative MRI. Obtained stereotactic coordinates were compared with expected intraoperative target coordinates. Resulting absolute errors in the X (medial-lateral), Y (anterior-posterior), and Z (dorsal-ventral) coordinates (ΔX, ΔY, and ΔZ) were then used to calculate the vector error (VE). The vector error describes the total error in 3-D space and represents our main outcome measure. Results: The vector error (mean ± SD) was 2.8 ± 1.3 for Nexframe and 2.5 ± 1.2 for the Leksell frame (p = 0.43). For Nexframe, absolute X, Y, and Z errors were 1.4 ± 1.3, 1.7 ± 1.2, and 1.0 ± 0.9 mm. For the Leksell frame, the absolute X, Y, and Z errors were 1.4 ± 1.0, 1.2 ± 1.0, and 1.3 ± 0.9 mm. On the anterior-posterior plane (Y coordinate), the Leksell frame was more accurate than Nexframe (p = 0.04). In contrast, Nexframe was more accurate on the dorsal-ventral plane (Z coordinate) (p = 0.04). There was no difference in accuracy between the two methods on the medial-lateral plane (X coordinate). Conclusion: This comparison of Nexframe and the Leksell frame shows that both techniques have equivalent overall 3-D accuracy.

Accuracy of Intraoperative Computed Tomography during Deep Brain Stimulation Procedures: Comparison with Postoperative Magnetic Resonance Imaging

“…Placement error of the Leksell system exceed these; hence, we feel that differences in lead representation on MRI and iCT are not clinically relevant [11,15]. The differences were largest in the dorsoventral plane where a more dorsal lead tip localization on iCT was noted.…”

“…Had they calculated euclidean distances of lead placement for both iCT and MRI and subsequently compared these, then possibly no significant difference would have been found. In addition, their absolute differences between both modalities did not differ significantly and were small enough (less than 0.5 mm) to be considered not clinically relevant [11,15]. …”

“…The surgical procedure of DBS placement is described in detail elsewhere [11]. The same team of movement disorder neurologist (L.V.M.)…”

Robot-assisted procedures in pediatric neurosurgery

“…For this reason, these procedures require the utmost accuracy of lead placement in order to achieve the best clinical efficacy while avoiding side effects. 10,44,60,64 In our preliminary experience, we treated 3 patients for primary dystonia (2 cases) and behavioral disorder (1 case). In all cases, we used bone fiducial registration.…”

Factors Affecting Stereotactic Accuracy in Image-Guided Deep Brain Stimulator Electrode Placement

“…Advances in intraoperative imaging now allow near real-time assessment of stereotactic accuracy during implantation of intracranial leads [9,10,11]. Frameless techniques are gaining acceptance, with an accuracy comparable to that of traditional, frame-based electrode implantation [12]. …”