Implementation and performance evaluation of a drilling assistive device for distal locking of intramedullary nails

Endoscopy-assisted distal locking of an intramedullary nail: A new experimental technique to reduce radiation exposure during distal locking of the intramedullary nails

Objectives

In this study, we aimed to introduce a new technique in which distal locking step was easier and safer for orthopedic trauma surgeons involving in the treatment of long bone fractures using an intranail endoscopic visualization and illumination method.

Materials and methods

A total of 20 fresh bovine hind limbs derived from healthy adults and killed for sale were dissected to obtain tibial bones. Two equal groups including 10 samples in each were prepared. We applied a standard nailing process in both groups: the study group (n=10) was locked by the new technique, intranail endoscopic illumination guidance and intranail visualization assistance locking technique and the control group (n=10) was locked by the classical free-hand fluoroscopic guidance technique. We measured the surgical period time and the radiation exposure time required for the distal locking in both groups.

Results

The radiation exposure time was statistically significantly lower in the study group compared to the control group. Also, the time period required for distal locking in the study group were statistically significantly lower than the control group. With the use of the intranail endoscopic illumination guidance and visualization assistance technique, the median period time required for the distal locking procedure reduced from 477.5 to 223.5 sec (p<0.001). The median time for radiation exposure dramatically reduced from 13.5 to 2 sec (p<0.001). The median attempt number reduced from 6.5 to 2 times (p<0.001).

Conclusion

This experimental study indicates that the endoscopic illumination and intranail visualization assistance technique can reduce the radiation exposure time and the period time required for distal locking compared to the free-hand fluoroscopic guidance.

Augmented reality based navigation for distal interlocking of intramedullary nails utilizing Microsoft HoloLens 2

BACKGROUND AND OBJECTIVE

The distal interlocking of intramedullary nail remains a technically demanding procedure. Existing augmented reality based solutions still suffer from hand-eye coordination problem, prolonged operation time, and inadequate resolution. In this study, an augmented reality based navigation system for distal interlocking of intramedullary nail is developed using Microsoft HoloLens 2, the state-of-the-art optical see-through head-mounted display.

METHODS

A customized registration cube is designed to assist surgeons with better depth perception when performing registration procedures. During drilling, surgeons can obtain accurate and in-situ visualization of intramedullary nail and drilling path, and dynamic navigation is enabled. An intraoperative warning system is proposed to provide intuitive feedback of real-time deviations and electromagnetic disturbances.

RESULTS

The preclinical phantom experiment showed that the reprojection errors along the X, Y, and Z axes were 1.55 ± 0.27 mm, 1.71 ± 0.40 mm, and 2.84 ± 0.78 mm, respectively. The end-to-end evaluation method indicated the distance error was 1.61 ± 0.44 mm, and the 3D angle error was 1.46 ± 0.46°. A cadaver experiment was also conducted to evaluate the feasibility of the system.

CONCLUSION

Our system has potential advantages over the 2D-screen based navigation system and the pointing device based navigation system in terms of accuracy and time consumption, and has tremendous application prospects.