Accuracy and Clinical Use of a Novel Aiming Device for Frameless Stereotactic Brain Biopsy

Abstract

Aiming devices enable the use of neuronavigation systems for rigid instrument guidance mimicking the possibilities of a frame-based system without having a stereotactic frame affixed to the skull. The aim of the presented work was to investigate the phantom targeting accuracy of the Vertek aiming device (Medtronic Inc., Louisville, USA) and whether it can be safely and accurately applied in a concept of minimally invasive brain biopsy in which multi-modal image fusion, image-to-patient registration and head immobilization were based on a non-invasive vacuum mouthpiece. A plastic model of a head with 20 target beads broadly distributed around the head volume was used for determination of CT-based targeting accuracy. Every target was punctured 5 times totaling 100 needle positionings. Accuracy was evaluated on postoperative CT scans with the needles in place. The mean normal deviation (n = 100) was 1.5 +/- 0.8 mm and the mean angle of deviation was 1.1 +/- 0.7 degrees. In a preliminary clinical series in ten patients diagnostic biopsy sampling of intracranial lesions with a median diameter of 28 mm (range: 12-90 mm) could be achieved in all patients and no biopsy related complications were recorded. The experimental results showed a similar accuracy to frame-based stereotaxy. The device facilitates trajectory alignment via two pivot joints and the actual depth and location of the biopsy needle can be monitored. Within the limitations of a preliminary study, brain biopsy may be accurately and safely performed for lesions > or = 12 mm.

A Miniature Optical Neuronavigation System for CT-Guided Stereotaxy

“…The authors also added that specific attention and adjustments needed to be made with the operative setup to avoid line-of-sight issues with the optical tracking technology. In addition, Widmann et al [7] reported a mean error of 1.5 ± 0.8 mm for the Medtronic StealthStation optically-based navigation system with the Vertek instrument positioner when targeting 100 points in a plastic head phantom using CT imaging. In a review of EM-based tracking technology, Rosenow and Sootsman [14] reported similar accuracy under ideal conditions for optically tracking technologies.…”

“…However, for needle placements for biopsies of small, deep-seated targets and electrode placement for deep-brain stimulation, frame-based stereotaxy is still considered by many as the gold standard due to its mechanical precision [3,4]. The advent of cranial stabilization system and skull-mounted trajectory guides in the early 2000s expanded traditional stereotactic indications for neuronavigation as they provided a fairly rigid platform [5,6,7,8]. …”

Target registration and target positioning errors in computer‐assisted neurosurgery: proposal for a standardized reporting of error assessment

“…Registration templates are denture fixed acrylic templates with integrated fiducial markers (5,30). External registration frames are head-surrounding constructions with markers, which are connected to a resin template or a vacuum mouthpiece (15)(16)(17)(31)(32)(33). Markers usually have to be manually defined in the image data.…”

Integration of the Image-Guided Surgery Toolkit (IGSTK) into the Medical Imaging Interaction Toolkit (MITK)

“…As a helpful tool in 3D navigation, aiming devices that are linked to the image-guided surgery navigation system allow for an accurate alignment of the trajectory and guidance of the PTC needle to the target [10][11][12][13]. The electromagnetic tracking system measures the real-time position of surgical tools and fiducials attached to the patient's anatomy.…”