The Navigation System Of Femoral Reduction Based On Three Dimensional Image

Femoral fracture is a relatively common clinical orthopedic diseases.Withthe aggravating trend of aging population and the traffic accidents becoming more frequent because of a growing numberof private cars in China,there is a significantly increasing incidence of fracture.The traditional methods of fracturereduction are implantation of plate,plaster fixation and surgical operation.But these methods have shortcomings such as large wound,hemorrhage and time consuming,and even may lead to neurovascular injury,infection,necrosis of femoral head and other symptoms.At present,the minimally invasive surgery of fractures based on C-arm which is two-dimensional image-guided has been widely used in clinical practice.When there are eager need of determining the location of fractures,size and geometry accurately,it is very difficult for the doctor to make an accurate judgment merely by observing a two-dimensional perspective imageC-arm.Andthe procedure depends heavily on the doctor’s experience.Also,X-rays from the C-arm during surgery can cause radiation hazards to the human body.In order to solve these above problems,this project designed an external fixation system for fracture reduction based on three dimensional image.For the purpose of solving the problem above,the navigation system of femoral reductionbased on three dimensional image is designed by the available fracture fixation external fixator,including preoperative planning and intraoperative real-time navigation.Preoperative planning integrates functions,such as three-dimensional visualization,construction of registration point set,pre-reduction,extraction of interest region and three-dimensional printing,assisting doctors to develop personalized procedure.Intraoperative real-time navigation is integrated with distance guidance and image guidance function,guiding the doctor to complete reduction.Moreover,a new method to extract points on cross sections offracture is put forwardinthis paper,includingrough and finesegmentations.The rough segmentation filtered out the points where the angle between vertex normal and bone axis were larger than a threshold.And the finesegmentation employed an improved region growing based on the relationship between these connected triangular facets.This method is not limited to the situation of missing a large number of points on the cross section due to the threshold setting,and the more complete section point cloud can be extracted to meet the needs of clinical fracture surgery.The accuracy and operating time of the system are verified by the model experiment.The correction errors of the preoperative and intraoperative of reduction are ranging from 0.75 mm to 1.66 mm,and the whole operating time is 6-8 minutes.These parameters could meet the clinical needs.