Corrective Osteotomy of Malunited Diaphyseal Fractures of the Forearm Simplified Using 3-Dimensional CT Data: Proposal of Our Simple Strategy Through Case Presentation

Three-Dimensional Printing in Hand Surgery

The medical application of 3-dimensional printing technology has evolved in the last decade, with an increasing variety of uses in hand surgery. The ability for patient-specific design, rapid prototyping, and low cost of production of 3-dimensional printed materials has led to this rise in clinical applications, both for common procedures and complex reconstructions. Within hand surgery, 3-dimensional printing can be applied in several broad categories: to construct patient-specific models for preoperative planning, to design orthotics and prosthetics to meet specific patient demands, to create patient-specific aids for intraoperative use, to generate patient-specific hardware and prostheses for implantation, and for applications for trainee education.

Overview of In-Hospital 3D Printing and Practical Applications in Hand Surgery

Three-dimensional (3D) printing is spreading in hand surgery. There is an increasing number of practical applications like the training of junior hand surgeons, patient education, preoperative planning, and 3D printing of customized casts, customized surgical guides, implants, and prostheses. Some high-quality studies highlight the value for surgeons, but there is still a lack of high-level evidence for improved clinical endpoints and hence actual impact on the patient's outcome. This article provides an overview over the latest applications of 3D printing in hand surgery and practical experience of implementing them into daily clinical routine.

Evaluation of CT-MR image registration methodologies for 3D preoperative planning of forearm surgeries

Computerized surgical planning for forearm procedures that considers both soft and bony tissue, requires alignment of preoperatively acquired computed tomography (CT) and magnetic resonance (MR) images by image registration. Normalized mutual information (NMI) registration techniques have been researched to improve efficiency and to eliminate the user dependency associated with manual alignment. While successfully applied in various medical fields, the application of NMI registration to images of the forearm, for which the relative pose of the radius and ulna likely differs between CT and MR acquisitions, is yet to be described. To enable the alignment of CT and MR forearm data, we propose an NMI-based registration pipeline, which allows manual steering of the registration algorithm to the desired image subregion and is, thus, applicable to the forearm. Successive automated registration is proposed to enable planning incorporating multiple target anatomical structures such as the radius and ulna. With respect to gold-standard manual registration, the proposed registration methodology achieved mean accuracies of 0.08 ± 0.09 mm (0.01-0.41 mm range) in comparison with 0.28 ± 0.23 mm (0.03-0.99 mm range) associated with a landmark-based registration when tested on 40 patient data sets. Application of the proposed registration pipeline required less than 10 minutes on average compared with 20 minutes required by the landmark-based registration. The clinical feasibility and relevance of the method were tested on two different clinical applications, a forearm tumor resection and radioulnar joint instability analysis, obtaining accurate and robust CT-MR image alignment for both cases.

3D printing in hand surgery

While 3D printing in hand surgery is still in its infancy, it offers new avenues in research, teaching, and personalized medicine. For these reasons, some surgeons may want to jump on the bandwagon of this trendy technology. But we cannot forget that its superiority over conventional techniques has not been demonstrated. Surgeons who want to work with 3D printed objects must master their use and the entire manufacturing process, otherwise they risk becoming dependent on engineers and/or medical device companies.

Radiological Society of North America (RSNA) 3D printing Special Interest Group (SIG): guidelines for medical 3D printing and appropriateness for clinical scenarios

Medical three-dimensional (3D) printing has expanded dramatically over the past three decades with growth in both facility adoption and the variety of medical applications. Consideration for each step required to create accurate 3D printed models from medical imaging data impacts patient care and management. In this paper, a writing group representing the Radiological Society of North America Special Interest Group on 3D Printing (SIG) provides recommendations that have been vetted and voted on by the SIG active membership. This body of work includes appropriate clinical use of anatomic models 3D printed for diagnostic use in the care of patients with specific medical conditions. The recommendations provide guidance for approaches and tools in medical 3D printing, from image acquisition, segmentation of the desired anatomy intended for 3D printing, creation of a 3D-printable model, and post-processing of 3D printed anatomic models for patient care.