Design and evaluation of a portable intra-operative unified-planning-and-guidance framework applied to distal radius fracture surgery

Abstract

Purpose

During a standard fracture reduction and fixation procedure of the distal radius, only fluoroscopic images are available for planning of the screw placement and monitoring of the drill bit trajectory. Our prototype intra-operative framework integrates planning and drill guidance for a simplified and improved planning transfer.

Methods

Guidance information is extracted using a video camera mounted onto a surgical drill. Real-time feedback of the drill bit position is provided using an augmented view of the planning X-rays. We evaluate the accuracy of the placed screws on plastic bones and on healthy and fractured forearm specimens. We also investigate the difference in accuracy between guided screw placement versus freehand. Moreover, the accuracy of the real-time position feedback of the drill bit is evaluated.

Results

A total of 166 screws were placed. On 37 plastic bones, our obtained accuracy was $1.01\,\pm \,0.56$ mm, $3.74^\circ \,\pm \,4.39^\circ$ and $1.70^\circ \,\pm \,1.35^\circ$ in tip position and orientation (azimuth and elevation), respectively. On the three healthy forearm specimens, our obtained accuracy was $1.63 \pm 0.91$ mm, $5.85^\circ \pm 4.93^\circ$ and $3.48^\circ \pm 3.07^\circ$. On the two fractured specimens, we attained: $1.39 \pm 0.47$ mm, $2.93^\circ \pm 1.83^\circ$ and $2.14^\circ \pm 1.84^\circ$. When screw plans were applied freehand (without our guidance system), the achieved accuracy was $1.73 \pm 0.82$ mm, $6.01^\circ \pm 4.94^\circ \,\mathrm{{and}}\, 3.52^\circ \pm 2.48^\circ$, while when they were transferred under guidance, we obtained $0.89 \pm 0.37$ mm, $2.85^\circ \pm 2.57^\circ \,\mathrm{{and}}\, 1.49^\circ \pm 1.17^\circ$.

Conclusions

Our results show that our framework is expected to increase the accuracy in screw positioning and to improve robustness w.r.t. freehand placement.