Patient-Specific 3D Printed Guides for Corrective Osteotomies of Malunited Radius

The purpose of this master thesis was to expand an existing medical modelling software, Segment 3DPrint, and develop a tool for surgical planning for corrective osteotomy of the forearm. Fractures of the forearm are very common and in some patients the fractured bone unites abnormally, causing a deformation. This is called a malunion and can affect the functionality of the wrist. The patients experience this as impaired rotation of the forearm or impaired extension and flexion of the wrist in addition to pain. The surgical planning tool aims to create a patient-specific cutting guide to be used intraoperatively during corrective surgery where the deformed bone is corrected. During the operation the guide will be placed on the malunited bone and outline the location and angle for the cut as well as where to drill the holes for a fixation plate. The primary focus is on radius malunion but this project will serve as a basis for other parts of the human body in the future. The process starts with 3D computed tomography (CT) images of the malunited radius and the contralateral, healthy, radius of the patient. The contralateral radius is mirrored in the software and used as a reference for the reconstruction of the malunited radius. The alignment of the malunited radius is performed by using intensity based image registration. After initial registration, the developed planning tool allows the user to adjust the alignment if necessary or otherwise desired. Both the proximal and distal ends of the radius are aligned to the healthy contralateral radius. A preferred location of the surgical cut is marked, followed by reconstruction of the deformed radius in compliance with proximal and distal alignment. When the desired anatomy of the reconstructed radius is achieved, the aligning information is translated back to the malunited radius, thus providing support for the design of the surgical cutting guide.En fraktur på underarmen är väldigt vanligt och ibland blir det fel under läkningsprocessen. Då kan benet bli deformerat och orsaka stora problem för den drabbade och man behöver korrigera med en operation. Det här projektet tar fram ett hjälpmedel för kirurgen som både kortar ner operationstiden och som förbättrar operationsresultatet för patienten