Measurement of the Femoral Head Diameter at Hemiarthroplasty of the Hip

AbstractThis paper is focusing on the measurement methods of the femoral head at the hip hemiarthroplasty surgery. The measurement result of 10 femoral head specimens using four different methods of Vernier calliper, ring gauge, CT scan and X-ray were compared. It is generally believed that under sizing of the implant may cover the errors of the measurement methods, but the result of this study shows that the callipers and ring gauge measurements are more reliable than the CT and X-ray methods. Conclusively, the full-circle ring gauge or femoral head template is the recommendation for measurement of the femoral head diameter in the hip hemiarthroplasty surgery

A medium invasiveness multi-level patient’s specific template for pedicle screw placement in the scoliosis surgery

Abstract Background Several methods including free-hand technique, fluoroscopic guidance, image-guided navigation, computer-assisted surgery system, robotic platform and patient’s specific templates are being used for pedicle screw placement. These methods have screw misplacements and are not always easy to be applied. Furthermore, it is necessary to expose completely a large portions of the spine in order to access fit entirely around the vertebrae. Methods In this study, a multi-level patient’s specific template with medium invasiveness was proposed for pedicle screw placement in the scoliosis surgery. It helps to solve the problems related to the soft tissues removal. After a computer tomography (CT) scan of the spine, the templates were designed based on surgical considerations. Each template was manufactured using three-dimensional printing technology under a semi-flexible post processing. The templates were placed on vertebras at four points—at the base of the superior-inferior articular processes on both left–right sides. This helps to obtain less invasive and more accurate procedure as well as true-stable and easy placement in a unique position. The accuracy of screw positions was confirmed by CT scan after screw placement. Results The result showed the correct alignment in pedicle screw placement. In addition, the template has been initially tested on a metal wire series Moulage (height 70 cm and material is PVC). The results demonstrated that it could be possible to implement it on a real patient. Conclusions The proposed template significantly reduced screw misplacements, increased stability, and decreased the sliding & the intervention invasiveness

Knee dynamic analysis based on 2D-to-3D registration of fluoroscopic and angiographic images / Amir Hossein Saveh ... [et al.]

This paper introduces a method to measure the kinematics of the knee using fluoroscopic imaging. The method involves two stages. In the first, the knee joint is recorded during normal gait by fluoroscopy using a mobile C-arm and an angiographic imaging system. The images then were processed to calculate the two-dimensional (2D) kinematics of the joint during the different phases of the gait cycle. This was then used to calculate three-dimensional (3D) kinematics of the joint. In parallel the reaction force on the knee joint was calculated using gait lab analysis. In the second stage, the 3D finite element model of the knee was created using computerised tomography (CT) and magnetic resonance imaging (MRI) data. The model was then used to analyse the joint contact loads during the gait cycle based on the input data obtained from the kinematic and reaction force data from stage one. This allowed the analysis of the mechanical behaviour of the knee and thus the stress distribution on the medial and lateral compartments of the knee