dc.description.abstract | According to national statistics result, people go for medical care due to the bone fracture in accident almost one person per minute. And there are around 30,000 cases of long bone fracture (femur and tibia) patients every year. Currently the most commonly treatment for long bone fracture fixation is implanting an intramedullary nail into marrow cavity of the long bone. For the therapeutic effect, intramedullary nail will be fastened with bone by locking screws in both proximal and distal sides of the nail. The bone is drilled by using K-wire instrument to pass through the locking hole, but usually the distal side locking holes are hard to be located because they are visible only under X-ray exposures and the nail deforms during the insertion process. So the surgeon must rely on fluoroscopy images to locate distal locking hole during surgery. The surgeon needs to spend a lot of time to figure out the positions and orientations of the locking holes and usually explore high radiation dosage.This project’s goal is to develop an image-based surgical navigation system for the distal locking of intramedullary nails, which can locate the positions and orientations of the distal locking holes.
First of all, taking two fluoroscopy images in different angle, which can determine the positions and orientations of the intramedullary nail axis in space. The 3D model of the intramedullary nail will be placed according to the calculate positions and orientations under the C-arm projection mode, and simulate C-arm projection to produce the distal locking holes image of intramedullary nails. The angle between the nail axis and the locking holes projections overlap area of the ellipse’s long axis have to be determined. The simulate images are compared with the actual image are taken from C-arm to find the most similar simulate images, and get a axis position and orientation of locking holes.Because the diameter of locking hole only have 5mm, freehand drilling holes could easily cause the wrong direction, so design a aid-drill which have a fine-tuning that can help the surgeon to complete the drilling surgery successfully. Experimental accuracy with C-arm shooting angle of 28.3 degrees ,the smallest is 0.28 in rotation, 0.78 mm translation; the largest is 1.90 in rotation, 1.92 mm translation. | en_US |