Maxillofacial reconstruction with prefabricated osseous free flaps: a 3-year experience with 24 patients. Plast Reconstr Surg
ABSTRACT Between January of 1998 and May of 2002, 25 prefabricated osseous free flaps (23 fibula and two iliac crest flaps) were transferred in 24 patients to repair maxillary (six flaps) or mandibular (eight flaps) defects after tumor resection, severe maxillary (four flaps) or mandibular (one flap) atrophy (Cawood VI), maxillary (one flap) or mandibular (three flaps) defects after gunshot injury, and maxillary (two flaps) defects after traffic accidents. Prefabrication included insertion of dental implants, positioned with a drilling template in a preplanned position, and split-thickness grafting. Drilling template construction was based on the prosthetic planning. The template determined the position of the implants and the site and angulation of osteotomies, if necessary. The mean delay between prefabrication and flap transfer was 6 weeks (range, 4 to 8 weeks). While the flap was harvested, a bar construction with overdentures was mounted onto the implants. The overdentures were used as an occlusal key for exact three-dimensional positioning of the graft within the defect. The bar construction also helped to stabilize the horseshoe shape of the graft. The follow-up period ranged from 2 months to 4 years (mean, 21 months), during which time two total and three partial flap losses occurred. One total loss was due to thrombosis of the flap veins during the delay period, whereas the other total loss was caused by spasm of the peroneal artery. Two partial losses were due to oversegmentation of the flaps with necrosis of the distal fragment, whereas one partial loss was caused by disruption of the vessel from the distal part. Of the 90 implants that were inserted into the prefabricated flaps during the study period, 10 were lost in conjunction with flap failure; of the remaining 80 implants, four were lost during the observation period, for a success rate of 95 percent. Flap prefabrication based on prosthetic planning offers a powerful tool for various reconstructive problems in the maxillofacial area. Although it involves a two-stage procedure, the time for complete rehabilitation is shorter than with conventional procedures.
Conference Paper: RADARSAT-I system commissioning and beyond[Show abstract] [Hide abstract]
ABSTRACT: Canada's first Earth observation satellite, RADARSAT-I was launched in a polar, sun-synchronous, dawn-dusk orbit by a Delta II rocket on November 4, 1995. The satellite carries a multi-mode C-band, HH polarization synthetic aperture radar (SAR) which provides choices in incidence angles (from less than 20° to more than 50°), resolutions (from 10 m to 100 m), and swath widths (from 45 km to 500 km). The satellite is programmed and commanded through a S-band link from the Control Centre at the Canadian Space Agency (CSA) in St. Hubert, Quebec to acquire the SAR data in the required mode as per user requests and to dump at X-band the corresponding data to ground receiving stations. The satellite has global acquisition capability through the on-board tape recorders. User requests for new acquisitions or processing archived SAR data are entered into the RADARSAT system through order desks. The corresponding data or products are delivered to users by data processing facilities. The system has been commissioned through months of on-orbit testing of the satellite along with operational demonstrations. The operation phase began on 1 April 1996 and should last for 5 years, the designed lifetime of the satellite. During this phase, RADARSAT data will be supplied to users around the world for a variety of applications and the satellite will be turned from right looking to left looking orientation twice to map the Antarctic. An overview of the RADARSAT-I system and operation is presented along with examples of the imageryElectrical and Computer Engineering, 1996. Canadian Conference on; 06/1996
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ABSTRACT: A new man-made shadowing model was proposed. This model enables us to estimate deterministically the man-made shadowing effects, which are one of the dominant factors with indoor radio communication. The model can be used with the numerous propagation prediction methods based on ray prediction. Moreover, it allows the selection of appropriate locations and antenna characteristics for macroscopic diversity branches for the base station. The increase in loss due to man-made shadowing is a function of frequency, polarization, antenna height, etcAntennas and Propagation Society International Symposium, 1996. AP-S. Digest; 08/1996
- Plastic & Reconstructive Surgery 09/2004; 114(2):607-9; author reply 609-10. DOI:10.1097/01.PRS.0000128502.66709.41 · 3.33 Impact Factor