Fraunhofer-Institut für Produktionsanlagen und Konstruktionstechnik IPK

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  • Publication
    RapidSplint: Virtual splint generation for orthognathic surgery - Results of a pilot series
    ( 2014)
    Adolphs, Nicolai
    ;
    Liu, Weichen
    ;
    Keeve, Erwin
    ;
    Hoffmeister, Bodo
    BACKGROUND:Within the domain of craniomaxillofacial surgery, orthognathic surgery is a special field dedicated to the correction of dentofacial anomalies resulting from skeletal malocclusion. Generally, in such cases, an interdisciplinary orthodontic and surgical treatment approach is required. After initial orthodontic alignment of the dental arches, skeletal discrepancies of the jaws can be corrected by distinct surgical strategies and procedures in order to achieve correct occlusal relations, as well as facial balance and harmony within individualized treatment concepts. To transfer the preoperative surgical planning and reposition the mobilized dental arches with optimal occlusal relations, surgical splints are typically used. For this purpose, different strategies have bee n described which use one or more splints. Traditionally, these splints are manufactured by a dental technician based on patient-specific dental casts; however, computer-assisted technologies have gained increasing importance with respect to preoperative planning and its subsequent surgical transfer. METHODS:In a pilot study of 10 patients undergoing orthognathic corrections by a one-splint strategy,two final occlusal splints were produced for each patient and compared with respect to their clinical usability. One splint was manufactured in the traditional way by a dental technician according to the preoperative surgical planning. After performing a CBCT scan of the patient's dental casts, a second splint was designed virtually by an engineer and surgeon working together, accor ding to the desired final occlusion. For this purpose, RapidSplint, a custom-made software platform, was used. After post-processing and conversion of the datasets into .stl files, the splints were fabricated by the PolyJet procedure using photo polymerization. During surgery, both splints were inserted after mobilization of the dental arches then compared with respect to their clinical usability according to theocclusal fitting.RESULTS:Using the workflow described above, virtual splints could be designed and manufactured for all patients in this pilot study. Eight of 10 virtual splints could be used clinicallyto achieve and maintain final occlusion after orthognathic surgery. In two cases virtual splints were not usable due to insufficient occlusal fitting, and even two of t he traditional splints were not clinically usable. In five patients where both types of splints were available, their occlusalfitting was assessed as being equivalent, and in one case the virtual splint showed even better occlusal fitting than the traditional splint. In one case where no traditional splint was available, the virtual splint proved to be helpful in achieving the final occlusion.CONCLUSIONS:In this pilot study it was demonstrated that clinically usable splints for orthognathic surgerycan be produced by computer-assisted technology. Virtual splint design was realized by RapidSplint®, an in-house software platform which might contribute in future to shorten preoperative workflows for the production of orthognathic surgicalsplints.
  • Publication
    Halverder leitet Berliner Zentrum für Mechatronische Medizintechnik. Interview
    ( 2012)
    Keeve, Erwin
    ;
    Beiing, Anke
    Der gebürtige Halverder, Prof. Dr. Erwin Keeve, leitet seit vier Jahren das Berliner Zentrum für Mechatronische Medizintechnik. Er entwickelte einen Röntgen-Roboter. Mit Anke Beiing sprach er über seinen Werdegang, seine Arbeit und seine Heimat.
  • Publication
    A noncontact laser-guided system for endoscopic computer-assisted sinus surgery
    ( 2012)
    Khan, Martin
    ;
    Kosmecki, Barotsz
    ;
    Reutter, Andreas
    ;
    Özbek, Christopher
    ;
    Keeve, Erwin
    ;
    Olze, Heidi
    The limited size of the nose leads to frequent instrument changes in navigated endonasal sinus surgery. Tracked instruments provide limited accuracy, and the pointer gives no navigation information during tissue removal. To overcome information loss, laser triangulation was integrated into navigation information. Accuracy and reliability of the laser-assisted distance-measuring system were evaluated within the distance of 0 and 20 mm. System accuracy of the laser endoscope was compared with a standard pointer using registration via bone screws and surface matching. Accuracy of the laser was 0.12 mm ± 0.12 mm with a reliability of 0.2 mm. The system accuracy of the laser endoscope was 0.59 mm ± 0.16 mm using bone screw registration and 0.64 mm ± 0.22 mm using surface matching. Additionally, laser endoscope is more accurate compared with the pointer using bone screw registration. Overall, navigation information was successfully integrated into an endoscope by laser triangulation with encouraging results.
  • Publication
    Overlay visualization in endoscopic ENT surgery
    ( 2011)
    Winne, Christian
    ;
    Khan, Martin
    ;
    Stopp, Fabian
    ;
    Jank, Emanuel
    ;
    Keeve, Erwin
    Purpose In endoscopic ENT surgery, the identification and localization of target structures is challenging-depth information is missing, relevant tissues could be hidden behind opaque material and image distortion affects the instrument handling. In this paper, a novel overlay visualization is presented that supports the surgeon by superimposing planning and navigation information on the endoscopic image. Method Target regions, which have been identified in preoperative CT data, are superimposed on the endoscopic image, allowing the use of guiding lines for distance visualization. To match the overlay information with the geometrically distorted endoscopic images, a new intraoperative calibration procedure has been developed. Results The accuracy of this new method has been verified by cadaver studies. Clinical evaluation in three paranasal sinus interventions was performed to show the intraoperative assistance and practicability with promising results. Conclusion The new techniques safely support the surgeon in locating target structures in the paranasal sinuses with little change in the actual workflow.