Navigation supported by image conversion. An experimented study on pelvic screw fixation

Within an experimental trial the new method of fluoroscopy based navigation was tested for percutanuous pelvic srew fixations. A regular C-arm was use d and the navigation system developed by Medivision. In a first step approp riate C-arm projections were defined for five standardized screw positions. Then precision and fluoroscopy time of 60 screws in 6 artificial pelves we re evaluated. For the sacroliacal screw in S1,S1 screw in S2, anterior column screw, post erior column screw and the supraacetabular ilium screw three to four approp riate projections were defined. These were all combinations of the known sp ecial pelvic views inlet / outlet and iliac/obturator. Using these standardized views the average fluoroscopy time was 6 seconds p er screw. 51 screws (85%) were inserted correctly. In five cases there was a slight deviation without perforating the cortex, four times the cortex wa s perforated.