Design and fabrication of rib prosthesis with full geometric shape based on CT scan and rapid prototyping

Objectives To design and fabricate rib prosthesis with full geometric shape based on digital imaging technique and rapid prototyping and measure the accuracy of rib prosthesis. Methods The CT images with DICOM format of right 8thrib of canine were transformed to images with STL format by OsiriX software and further modified and transformed to files with IGS format by UG software.The canine rib prosthesis were manufactured with photosensitive materials. The rib prosthesis and dogs' authentic rib were scanned by three dimensional laser scanning system and analyzed by Geomagic Qualify software. With the authentic rib as the template,we set the deviation within ±0.5mm. The report was automatically generated judging the difference. Results The canine rib prostheses with full geometric shape were obtained. About 30 thousands point cloud data was acquired.The average deviation was +0.243/-0.166 mm and the standard deviation was +0.324 mm between the prosthesis and authentic ribs. About 70.31% of point cloud data range from-0.167 to +0.167,69% of standard deviation of point cloud data range from-1 to +1,93% of standard deviation of point cloud data range from-2 to +2. Conclusions It is feasible to design and fabricate rib prosthesis with full geometric shape based on CT scan combined with rapid prototyping,which is rapid,direct and accurate. The prosthesis matches almost completely the shape of the authentic rib. Improvement should be made based on the deviation suggested by the scanning.