3D-printing of the elbow in complex posttraumatic elbow-stiffness for preoperative planning, surgery-simulation and postoperative control

Protocol for Converting DICOM Files to STL Models Using 3D Slicer and Ultimaker Cura

Background/Objectives: 3D printing has become an invaluable tool in medicine, enabling the creation of precise anatomical models for surgical planning and medical education. This study presents a comprehensive protocol for converting DICOM files into three-dimensional models and their subsequent transformation into GCODE files ready for 3D printing. Methods: We employed the open-source software "3D Slicer" for the initial conversion of the DICOM files, capitalising on its robust capabilities in segmentation and medical image processing. An optimised workflow was developed for the precise and efficient conversion of medical images into STL models, ensuring high fidelity in anatomical structures. The protocol was validated through three case studies, achieving elevated structural fidelity based on deviation analysis between the STL models and the original DICOM data. Furthermore, the segmentation process preserved morphological accuracy within a narrow deviation range, ensuring the reliable replication of anatomical features for medical applications. Our protocol provides an effective and accessible approach to generating 3D anatomical models with enhanced accuracy and reproducibility. In later stages, we utilised the "Ultimaker Cura" software to generate customised GCODE files tailored to the specifications of the 3D printer. Results: Our protocol offers an effective, accessible, and more accurate solution for creating 3D anatomical models from DICOM images. Furthermore, the versatility of this approach allows for its adaptation to various 3D printers and materials, expanding its utility in the medical and scientific community. Conclusions: This study presents a robust and reproducible approach for converting medical data into physical three-dimensional objects, paving the way for a wide range of applications in personalised medicine and advanced clinical practice. The selection of sample datasets from the 3D Slicer repository ensures standardisation and reproducibility, allowing for independent validation of the proposed workflow without ethical or logistical constraints related to patient data access. However, we acknowledge that future work could expand upon this by incorporating real patient datasets and benchmarking the protocol against alternative segmentation methods and software packages to further assess performance across different clinical scenarios. Essentially, this protocol can be particularly characterised by its commitment to open-source software and low-cost solutions, making advanced 3D modelling accessible to a wider audience. By leveraging open-access tools such as "3D Slicer" and "Ultimaker Cura", we democratise the creation of anatomical models, ensuring that institutions with limited resources can also benefit from this technology, promoting innovation and inclusivity in medical sciences and education.

Elbow stiffness due to malunited capitellum fracture: A case report and the role of 3D printing in surgical management

INTRODUCTION

Elbow stiffness is an uncommon condition that significantly impacting a patient's daily activities. Trauma is the most frequent cause of elbow stiffness. However, capitellum fractures are rare, accounting for approximately 1 % of elbow fractures. They are often misdiagnosed due to nonspecific symptoms and the complex anatomy of the elbow joint.

CASE PRESENTATION

We report the case of a 54-year-old female who presented with left elbow stiffness eight months after a traumatic incident. On physical examination, her left elbow extension was +10°, and flexion was restricted to 65°, with no limitation in pronation or supination. Imaging studies revealed a malunited capitellum with osteophytes at the posterolateral site of the olecranon. A 3D-printed model of her elbow was created based on a CT scan to aid surgical planning. She underwent capsulectomy and osteotomy and was stabilized with two bioabsorbable P(L/DL)LA pins. Six months postoperatively, the patient's elbow range of motion was fully restored, and no complications were observed.

CLINICAL DISCUSSION

Elbow stiffness resulting from the malunion of a capitellum fracture typically necessitates surgical intervention to restore functional movement in the elbow.

CONCLUSION

Capitellum fractures are uncommon and frequently underdiagnosed, leading to complications such as elbow stiffness and reduced functionality. Early detection is crucial, as delayed diagnosis can result in complex management due to malunion. 3D printing from CT scans helps surgeons accurately evaluate malunions and plan precise surgical interventions.

An Automatic Method for Elbow Joint Recognition, Segmentation and Reconstruction

Elbow computerized tomography (CT) scans have been widely applied for describing elbow morphology. To enhance the objectivity and efficiency of clinical diagnosis, an automatic method to recognize, segment, and reconstruct elbow joint bones is proposed in this study. The method involves three steps: initially, the humerus, ulna, and radius are automatically recognized based on the anatomical features of the elbow joint, and the prompt boxes are generated. Subsequently, elbow MedSAM is obtained through transfer learning, which accurately segments the CT images by integrating the prompt boxes. After that, hole-filling and object reclassification steps are executed to refine the mask. Finally, three-dimensional (3D) reconstruction is conducted seamlessly using the marching cube algorithm. To validate the reliability and accuracy of the method, the images were compared to the masks labeled by senior surgeons. Quantitative evaluation of segmentation results revealed median intersection over union (IoU) values of 0.963, 0.959, and 0.950 for the humerus, ulna, and radius, respectively. Additionally, the reconstructed surface errors were measured at 1.127, 1.523, and 2.062 mm, respectively. Consequently, the automatic elbow reconstruction method demonstrates promising capabilities in clinical diagnosis, preoperative planning, and intraoperative navigation for elbow joint diseases.

Three-dimensional printed models for surgery planning of post-traumatic stiff elbow: Current concepts

The post-traumatic stiff elbow is a challenge for the surgeon, requiring expertise for the treatment choice and accurate planning. Stiffness can result from traumatic injury involving the periarticular soft tissues and the joint articular surfaces. In this article, we want to assess the impact of three-dimensional (3D) printed models in selecting the appropriate surgical strategy for this pathology. Six cases of increasing complexity regarding post-traumatic stiff elbow were submitted to four expert elbow surgeons who had the possibility to evaluate videos and reports of clinical examination, plain radiograms and CT with 3D reconstruction for each case. After a first treatment proposition given by the experts for each patient, a three-dimensional printed model of each elbow based on the CT was provided to the surgeons, asking them to evaluate again all the cases having the possibility to assess also the 3D models. In the four most complex cases all surgeons found more beneficial the use of three-dimensional representation for treatment planning and rate the risk of complications than the sole CT imaging with 3D reconstruction and many of them changed surgical strategy after analysing the model. 3D printing technology is a useful tool in surgery planning for treating complex cases of post traumatic elbow stiffness, especially in the presence of joint deformity. LEVEL OF EVIDENCE: IV.