Digital design and rapid manufacturing in orbital wall reconstruction

Trauma and disease can cause bone damage and defects which need to be reconstructed. These may be repaired by using alloplastic implants made from various inert materials. The development of medical imaging and especially imaging software has made it possible to create various kinds of 3D models from medical images. Traditionally, implants have been manually bended and shaped intraoperatively or preoperatively using anatomic solid models. Virtual design and rapid manufacturing of the implant obviate the manual procedure and may result in more accurate and economical implants. Different kinds of modeling software were used in this study and their suitability for refining 3D models from medical images was investigated. We examined different ways to achieve desired geometries by utilizing the appropriate enabling software features and referring to the 3D models made directly from the images. We also examined the possibilities of transforming the geometries into a volumetric net, which could be rapid manufactured. As a result of this study a patient specific customized 3D model of an implant was designed, a volumetric net formed and several test pieces rapid-manufactured from stainless steel and titanium. Titanium reconstruction plate was finally rapid manufactured and implanted onto injured orbital wall of a patient. In this paper we describe a novel design and manufacturing method for implants by combining established techniques. This offers the medical profession new means to manage patients with bone tissue defects.