Registration Accuracy and Practicability of Laser-Directed Surface Matching

Abstract

The aim of our study was to evaluate the registration accuracy and practicability of a new laser registration technique in comparison to marker registration. From January to August 2001, 36 patients (23 male, 13 female) with brain lesions were operated with navigational guidance. Thirty-five patients were registered by paired-point registration. In 16 patients, a second registration was carried out using a special laser pointer for surface matching (z-touch trade mark, BrainLab, Heimstetten, Germany). Accuracy was evaluated by touching seven anatomic landmarks and a target fiducial with the nonsterile pointer. The distance from the virtual pointer tip to these points was determined on the monitor display (600% zoom). Laser registration is fully retrospective and allows registrations when no markers are applied. z-touch trade mark registration is more sophisticated and time-consuming than marker-based registration (registration time for z-touch trade mark = 7.4 +/- 3.7 min; for markers = 4.1 +/- 1.7 min; p < 0.005). Marker registration proved to be more accurate than z-touch trade mark registration with regard to localization of anatomical landmarks and target fiducials (precision with z-touch trade mark = 2.77 +/- 1.64 mm; with markers = 1.31 +/- 0.87 mm; p < 0.01). Although the registration error was increased and preparation time prolonged with the z-touch trade mark technique, it proved to be a valuable option, especially in children.

Point-to-point registration with mandibulo-maxillary splint in open and closed jaw position. Evaluation of registration accuracy for computer-aided surgery of the mandible

“…Our results are also comparable with those for other registration methods such as laser surface scanning, boneimplanted fiduciary markers, and anatomical structures (Schlaier et al, 2002;Marmulla et al, 2004a;Hoffmann et al, 2005b;Hardy et al, 2006;Pham et al, 2007). The use of a CBCT dataset seems to lead to the same results as those obtained with a CT dataset (Eggers et al, 2009).…”

“…Previous studies have evaluated general precision (Schlaier et al, 2002;Hoffmann et al, 2005b;Metzger et al, 2007) and concentrated on navigation precision in the maxillary and periorbital region (Marmulla et al, 2004b;Marmulla et al, 2004a;Hardy et al, 2006) or precision in the cranium (Luebbers et al, 2008).…”

Image-to-patient registration by natural anatomical surfaces of the head

“…The SNN++ system has to calculate one additional transformation to match the coordinate system of the laser scanner and the that of the infrared camera. However, reports in literature showed a considerably less accurate registration with the z-touch system than was achieved in our study [36]. On the one hand this is explained the lower number of recorded points (ztouch: hundreds of points, SNN++ approx.…”

Registration for computer-navigated surgery in edentulous patients: A problem-based decision concept

“…These have to be interpreted very carefully because the study design excluded the influence of soft tissue movements, and those are supposed to have the biggest impact on precision of surface matching techniques. However, our clinical experiences as well as the numerous studies do suggest acceptable accuracy for laser surface matching (Marmulla et al, 1997a;Raabe et al, 2002;Schlaier et al, 2002;Marmulla et al, 2003;Troitzsch et al, 2003;Marmulla et al, 2004a;Marmulla et al, 2004b;Marmulla et al, 2004c;Hoffmann et al, 2005;Marmulla et al, 2005a). This technique very often does not need additional 3D imaging for surgical navigation and has no need of preoperative invasive procedures in order to prepare the patient for the computerassisted surgery.…”