Virtual Fracture Reduction Research Articles

Augmented reality patient-specific reconstruction plate design for pelvic and acetabular fracture surgery

The objective of this work is to develop a preoperative reconstruction plate design system for unilateral pelvic and acetabular fracture reduction and internal fixation surgery, using computer graphics and augmented reality (AR) techniques, in order to respect the patient-specific morphology and to reduce surgical invasiveness, as well as to simplify the surgical procedure. Our AR-aided implant design and contouring system is composed of two subsystems: a semi-automatic 3D virtual fracture reduction system to establish the patient-specific anatomical model and a preoperative templating system to create the virtual and real surgical implants. Preoperative 3D CT data are taken as input. The virtual fracture reduction system exploits the symmetric nature of the skeletal system to build a "repaired" pelvis model, on which reconstruction plates are planned interactively. A lightweight AR environment is set up to allow surgeons to match the actual implants to the digital ones intuitively. The effectiveness of this system is qualitatively demonstrated with 6 clinical cases. Its reliability was assessed based on the inter-observer reproducibility of the resulting virtual implants. The implants designed with the proposed system were successfully applied to all cases through minimally invasive surgeries. After the treatments, no further complications were reported. The inter-observer variability of the virtual implant geometry is 0.63mm on average with a standard deviation of 0.49mm. The time required for implant creation with our system is 10min on average. It is feasible to apply the proposed AR-aided design system for noninvasive implant contouring for unilateral fracture reduction and internal fixation surgery. It also enables a patient-specific surgical planning procedure with potentially improved efficiency.

An interactive surgical planning tool for acetabular fractures: initial results

BackgroundAcetabular fractures still are among the most challenging fractures to treat because of complex anatomy, involved surgical access to fracture sites and the relatively low incidence of these lesions. Proper evaluation and surgical planning is necessary to achieve anatomic reduction of the articular surface and stable fixation of the pelvic ring. The goal of this study was to test the feasibility of preoperative surgical planning in acetabular fractures using a new prototype planning tool based on an interactive virtual reality-style environment.Methods7 patients (5 male and 2 female; median age 53 y (25 to 92 y)) with an acetabular fracture were prospectively included. Exclusion criterions were simple wall fractures, cases with anticipated surgical dislocation of the femoral head for joint debridement and accurate fracture reduction. According to the Letournel classification 4 cases had two column fractures, 2 cases had anterior column fractures and 1 case had a T-shaped fracture including a posterior wall fracture.The workflow included following steps: (1) Formation of a patient-specific bone model from preoperative computed tomography scans, (2) interactive virtual fracture reduction with visuo-haptic feedback, (3) virtual fracture fixation using common osteosynthesis implants and (4) measurement of implant position relative to landmarks. The surgeon manually contoured osteosynthesis plates preoperatively according to the virtually defined deformation. Screenshots including all measurements for the OR were available.The tool was validated comparing the preoperative planning and postoperative results by 3D-superimposition.ResultsPreoperative planning was feasible in all cases. In 6 of 7 cases superimposition of preoperative planning and postoperative follow-up CT showed a good to excellent correlation. In one case part of the procedure had to be changed due to impossibility of fracture reduction from an ilioinguinal approach. In 3 cases with osteopenic bone patient-specific prebent fixation plates were helpful in guiding fracture reduction. Additionally, anatomical landmark based measurements were helpful for intraoperative navigation.ConclusionThe presented prototype planning tool for pelvic surgery was successfully integrated in a clinical workflow to improve patient-specific preoperative planning, giving visual and haptic information about the injury and allowing a patient-specific adaptation of osteosynthesis implants to the virtually reduced pelvis.

Virtual 3D planning of acetabular fracture reduction

Displaced acetabular fractures are best treated with open reduction to achieve anatomic reduction and maximize the chance of a good functional outcome. Because of the anatomic complexity and often limited visualization, fracture reduction can be difficult. Virtual planning software can allow the surgeon to understand the fracture morphology and to rehearse reduction maneuvers. The purpose of this study was to determine the effect of a novel virtual fracture reduction module on time and accuracy of reduction. Four acetabular fracture patterns were created in synthetic pelves, which were implanted with fiducial markers and were registered with CT scan. Ten surgeons used virtual fracture reduction software or conventional 2D planning methods and immediately reduced the fractures blindly in a viscous gel medium. 3D imaging was again performed and the accuracy of reduction was assessed. The average malreduction was significantly improved following planning with the virtual software compared to the standard technique. The time taken for reduction was also significantly less for two of the four fracture patterns. Virtual software may be useful for visualizing and planning treatment of fractures of the acetabulum, potentially leading to more accurate and efficient reductions, and may also be an effective educational tool.