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Proceedings Paper

Computer-aided insertion of endosteal implants in the zygoma: a pilot study
Author(s): Wolfgang Birkfellner; Franz Watzinger; Felix Wanschitz; F. Ziya; J. Kremser; A. Potyka; R. Mayr; Klaus Huber; F. Kainberger; Rolf Ewers; Helmar Bergmann
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Paper Abstract

Endosteal implants facilitate obturator prosthesis fixation in tumor patients after maxillectomy. Previous clinical studies shown however, that survival of implants placed into available bone after maxillectomy is generally poor. Implants positioned optimally in residual zygomatic bone provide superior stability form a biomechanical point of view as well as improved survival. In a pilot study, we have assessed the precision of VISIT, a surgical navigation system developed for research purposes at our institution. VISIT is based on the AVW-library and a number of in-house developed algorithms for communication with an optical tracker and patient-to-CT-registration. The final platform independent application was assembled within 6 man-months using ANSI-C and Tcl/Tk. Five cadaver specimens underwent hemimaxillectomy. The cadaver head was matched to a preoperative high resolution CT by using implanted surgical microscrews as fiducial markers. The position of a surgical drill relative to the cadaver head was determined with an optical tracking system. Implants were placed into the zygomatic arch where maximum bone volume was available. The results were assessed using test for allocation accuracy and postoperative CT-scans of the cadaver specimens. The average allocation accuracy of landmarks on the bony skull was 0.6 +/- 0.3 mm determined with a 5 degree-of-freedom pointer probe. The allocation accuracy of the tip of the implant burr was 1.7 +/- 0.4 mm. The accuracy of the implant position compared to the planned position was 1.5 +/- 1.1 mm. 8 out of 10 implants were inserted with maximum contact to surrounding bone, two implants were located unfavorably. However, reliable placement of implants in this region is difficult to achieve. The techqni3u described in this paper may be very helpful in the management of patients after maxillary resection without sufficient retention for obturator prostheses.

Paper Details

Date Published: 18 April 2000
PDF: 9 pages
Proc. SPIE 3976, Medical Imaging 2000: Image Display and Visualization, (18 April 2000); doi: 10.1117/12.383048
Show Author Affiliations
Wolfgang Birkfellner, Univ. of Vienna General Hospital (Austria)
Franz Watzinger, Univ. of Vienna Medical School (Austria)
Felix Wanschitz, Univ. of Vienna Medical School (Austria)
F. Ziya, Univ. of Vienna Medical School (Austria)
J. Kremser, Univ. of Vienna Medical School (Austria)
A. Potyka, Univ. of Vienna Medical School (Austria)
R. Mayr, Univ. of Vienna Medical School (Austria)
Klaus Huber, Univ. of Vienna General Hospital (Austria)
F. Kainberger, Univ. of Vienna Medical School (Austria)
Rolf Ewers, Univ. of Vienna Medical School (Austria)
Helmar Bergmann, Univ. of Vienna General Hospital and Ludwig-Boltzmann Institute of Nuclear Medicine (Austria)

Published in SPIE Proceedings Vol. 3976:
Medical Imaging 2000: Image Display and Visualization
Seong Ki Mun, Editor(s)

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