Computer Vision and 3D Printing Can Aid in the Insertion of Intramedullary Nails for Long Bone Fractures

Freehand Technique

One of the most commonly used methods for securing the nail in its distal part is the freehand technique. According to the authors of the study, however, this method is less accurate and additionally requires multiple fluoroscopic imaging, which significantly increases the radiation exposure of the procedure.

The team, led by Zakaria Chabihi from the Traumatology and Orthopedic Department at the University Hospital in Marrakech, therefore focused in their study, published in the journal 3D Printing in Medicine, on creating a new method that shortens the duration of the procedure, increases accuracy, and reduces radiation exposure during surgery.

The result of the research is a system that consists of a targeting device partly printed on a 3D printer and special software that utilizes computer vision and artificial intelligence algorithms.

Targeting Device

The foundation of the entire system is a targeting device that consists of four parts: the main telescopic arm, universal surgical clamps, a viewfinder arm, and a contrast targeting cross. The device is designed to be compatible with most commonly used nails and easy to manipulate. The use of 3D printing for its production, according to the authors, also allowed for the rapid production of several prototypes and quick modifications of their design.

The base of the device is a universal surgical clamp attached to the proximal end of the nail, ensuring the stability of the entire system. Attached to the clamp is the telescopic arm, which represents the horizontal X-axis and allows for adjustment of distance from the surgical clamp to the viewfinder. It can be extended or retracted and adjusted for all nail lengths using a screw clamping mechanism.

Serving as the Y-axis is the viewfinder clamp, which allows for adjustment of the height and angle of the targeting mechanism. The actual viewfinder is comprised of a circular opening that guides the surgeon to align the drill with the distal hole of the nail.

Software Solution on Mobile

The system’s software was developed as a mobile application and works on the principles of computer vision. It uses images from the C-arm as input data, which, based on edge detection algorithms, Hough transformation, perspective interpolation, and vector calculations, determines how the targeting system should be correctly set up and calibrated.

Results and Limitations

The effectiveness of the new method in practice was verified based on several different criteria, such as the time from the start of calibration to the start of the procedure or the accuracy of the final targeting. The conclusions of the research, according to its authors, showed that the device demonstrates promising results in terms of time efficiency and high accuracy of the procedures performed. They also see a significant advantage in the low costs of production and maintenance.

Despite promising results, the researchers also note some limitations of their device. Possible weaknesses include the risk of calculation errors due to poorly lit input images or other variables that enter into the entire process.

Editorial Team, Medscope.pro

Source: Chabihi, Z., Nouidi, N., Demnati, B. et al. Fast and accurate distal locking of interlocked intramedullary nails using computer-vision and a 3D printed device. 3D Print Med 10, 28 (2024), doi: 10.1186/s41205-024-00221-2.