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ABSTRACT: Computer-aided surgery (CAS) allows for real-time intraoperative feedback resulting in increased accuracy, while reducing intraoperative radiation. CAS is especially useful for the treatment of certain pelvic ring fractures, which necessitate the precise placement of screws. Flouroscopy-based CAS modules have been developed for many orthopedic applications. The integration of the isocentric flouroscope even enables navigation using intraoperatively acquired three-dimensional (3D) data, though the scan volume and imaging quality are limited. Complicated and comprehensive pathologies in regions like the pelvis can necessitate a CT-based navigation system because of its larger field of view. To be accurate, the patient's anatomy must be registered and matched with the virtual object (CT data). The actual precision within the region of interest depends on the area of the bone where surface matching is performed. Conventional surface matching with a solid pointer requires extensive soft tissue dissection. This contradicts the primary purpose of CAS as a minimally invasive alternative to conventional surgical techniques. We therefore integrated an a-mode ultrasound pointer into the process of surface matching for pelvic surgery and compared it to the conventional method. Accuracy measurements were made in two pelvic models: a foam model submerged in water and one with attached porcine muscle tissue. Three different tissue depths were selected based on CT scans of 30 human pelves. The ultrasound pointer allowed for registration of virtually any point on the pelvis. This method of surface matching could be successfully integrated into CAS of the pelvis.
Journal of Orthopaedic Research 07/2008; 26(6):860-4. · 2.81 Impact Factor
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ABSTRACT: Surgical navigation has proven to be a minimally invasive procedure that enables precise surgical interventions with reduced exposure to irradiation for patient and personnel. Fluoroscopy-based modules have prevailed on the market. For certain operations of the pelvis computed tomography is necessary with its high imaging quality and considerably larger scan volume. To enable navigation in these cases, matching of the CT data set and the patient's real pelvic bone is essential. The common pair point-matching algorithm is complemented by the surface-matching algorithm to achieve an even higher overall precision of the system. For conventional surface matching with a solid pointer, the bone has to be exposed from soft tissue quite extensively, using a solid pointer. This conflicts with the claim of computer-assisted surgery to be minimally invasive. We integrated an A-mode ultrasonic pointer with the intention to perform extended surface matching on the pelvic bone noninvasively. Related to the conventional method, comparable and to some extent even improved precision conditions could be established.
Der Unfallchirurg 04/2008; 111(3):162-6. · 0.61 Impact Factor
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ABSTRACT: Die chirurgische Navigation hat sich als ein Verfahren bewährt, das minimal-invasives Vorgehen erlaubt und sehr präzise chirurgische
Eingriffe sowie eine Reduzierung der Strahlenbelastung für Patient und Personal ermöglicht. Durchgesetzt haben sich die Fluoroskopie-basierten
Navigationssysteme. Für bestimmte Beckeneingriffe sind jedoch die hohe Bildqualität und das deutlich größere Scan-Volumen
der Computertomographie (CT) durchaus erforderlich. Um in diesen Fällen navigieren zu können, benötigt man eine Registrierung.
Damit kann der reelle Knochen des Patienten mit dem CT-Datensatz abgeglichen werden. Paar-Punkt-Registrierung (PPR) und Oberflächenregistrierung
(OR) sind notwendig, um gute Präzisionsbedingungen zu schaffen. Für eine herkömmliche OR müssen Punkte der Beckenknochenoberfläche
unter teilweise erheblicher Invasivität auf der exponierten Knochenoberfläche registriert werden. Dies stellt den Anspruch
der Navigation in Frage, ein minimal-invasives Vorgehen zu ermöglichen. Wir integrierten daher einen A-Mode-Ultraschall-Pointer,
um eine erweiterte OR am Beckenknochen ohne invasives Vorgehen durchführen zu können. Wir konnten so eine gleich gute und
z.T. verbesserte Genauigkeit im Vergleich zur herkömmlichen Methode erzielen.
Surgical navigation has proven to be a minimally invasive procedure that enables precise surgical interventions with reduced
exposure to irradiation for patient and personnel. Fluoroscopy-based modules have prevailed on the market. For certain operations
of the pelvis computed tomography is necessary with its high imaging quality and considerably larger scan volume. To enable
navigation in these cases, matching of the CT data set and the patient’s real pelvic bone is essential. The common pair point-matching
algorithm is complemented by the surface-matching algorithm to achieve an even higher overall precision of the system. For
conventional surface matching with a solid pointer, the bone has to be exposed from soft tissue quite extensively, using a
solid pointer. This conflicts with the claim of computer-assisted surgery to be minimally invasive. We integrated an A-mode
ultrasonic pointer with the intention to perform extended surface matching on the pelvic bone noninvasively. Related to the
conventional method, comparable and to some extent even improved precision conditions could be established.
Der Unfallchirurg 02/2008; 111(3):162-166. · 0.61 Impact Factor
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ABSTRACT: An unusual case of an anterior column fracture of the acetabulum with extended marginal impaction at the posterior column is presented. Fracture fixation was primarily performed by an ilioinguinal approach followed by a posterior approach with surgical dislocation of the hip to reduce the impacted fragments.
Der Unfallchirurg 08/2006; 109(7):587-92. · 0.61 Impact Factor
