Purpose: To determine the accuracy of frameless stereotactic computed tomographic (CT)-guided wire placement for percutaneous fixation of posterior pelvic ring fractures in human cadavers.
Materials and methods: Four intact human cadavers were fixated in a double-vacuum immobilization system. A 2.5-mm helical CT dataset was obtained and transferred to the three-dimensional (3D) navigation system. In every specimen, two paths on each side (total number, 16) were defined on multiplanar reconstructions of the 3D CT datasets, simulating fixation of the iliosacral joint. An aiming device was adjusted according to the plan, and a 2.5-mm pin was advanced through the aiming device to the precalculated target point. To determine the accuracy of pin placement, a control CT scan was co-registered to the planning CT scan (with the planned trajectories). The distance between the planned and achieved positions of the pins (3D accuracy) was calculated in millimeters.
Results: The mean 3D accuracy was 1.84 mm +/- 0.9 (standard deviation) at the bone entrance point and 2.5 mm +/- 1.2 at the target, as determined with image fusion between the planning CT scan and the control CT scan with the pins in place.
Conclusions: The described technique enables accurate placement of pins in the pelvis and may be useful for percutaneous orthopedic procedures.