title: 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.
  
  
  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 (x0394;X, x0394;Y, and x0394;Z) 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).
  
  
  CONCLUSIONS
  This comparison of Nexframe and the Leksell frame shows that both techniques have equivalent overall 3-D accuracy.
authors.affiliation: Department of Neurological Sciences, Rush University Medical Center, Chicago, Ill., USA.
authors.forename: Maarten
authors.initials: M
authors.lastname: Bot
authors.forename: Pepijn
authors.initials: P
authors.lastname: van den Munckhof
authors.forename: Roy
authors.initials: R
authors.lastname: Bakay
authors.forename: Diane
authors.initials: D
authors.lastname: Sierens
authors.forename: Glenn
authors.initials: G
authors.lastname: Stebbins
authors.forename: Leo
authors.initials: L
authors.lastname: Verhagen Metman
mesh_terms: D000328:Adult; D000368:Aged; D046690:Deep Brain Stimulation / Q000295:instrumentation / Q000379:methods*; D004567:Electrodes, Implanted; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D008875:Middle Aged; D009069:Movement Disorders / Q000628:therapy*; D011184:Postoperative Period; D013238:Stereotaxic Techniques / Q000295:instrumentation*; D016896:Treatment Outcome