In vitro study using cadavers for evaluation of a bone-mountable surgical robot system

This paper describes a bone-mountable surgical robot system for hip surgery and its in vitro experiments with cadavers. The system eliminates the need for obtaining CT scan data by adopting gauge-based, bone-mounting registration method and is designed to replace only the broaching procedure, which is known to be the most error-prone procedure in the manual surgery. The performance of this system is evaluated with specimen of six human cadavers. X-ray images and photographed image of femurs are utilized for measuring the difference between the implant and the anatomical axes. As this deviation implies how the gait pattern of the operated patient may be influenced by the surgery, the amount of deviation is used as the indicative of system performance. The nominal differences of anteversion angle, valgus-varus angle, and flexion-extension angle are 0.02/spl plusmn/2.73/spl deg/, 0.98 /spl plusmn/0.39/spl deg/ and 0.51/spl plusmn/0.87/spl deg/, respectively. In case of the change in leg length after the surgery, the nominal error is -0.88/spl plusmn/1.26 mm. Experimental results show that the performance of the developed system is comparable to other surgical robots that use preoperative planning with CT scan data.