Use of mechatronic devices for enhancement of safety during screw placement in orthopaedic surgery

2013-09-03T13:37:06Z (GMT) by Rolf L. Thomas
The internal fixation of fractures in bone with the aid of plates and screws is a common procedure in orthopaedic surgery. The prevention of over-tightening is entirely dependent upon the skill and judgement of the surgeon. The research reported here proposed two independent methods for the prevention of overtightening of orthopaedic screws. The first method developed by this research was a mathematical model for predicting the maximum torque that may be applied to a screw before over-tightening occurs. Use of the model would allow surgeons to set a torque-limiting device to prevent over-tightening during surgery. The model would also allow the surgeon to predict the maximum pullout force that screwlbone interface can withstand before failure occurs. The second method developed in this research to prevent over-tightening was the automated screwdriver. It was shown that the automated screwdriver could detect the onset of tightening thus preventing over-tightening without the aid of the mathematical model. The automated screwdriver was demonstrated to perform the following tasks:- (i) Pre-tapping (ii) Tightening of non-self-tapping and self-tapping screws. (iii) Insertion of self-drilling external screws. This research has conclusively demonstrated that both the proposed methods for the prevention of over-tightening orthopaedic screws are a contribution to orthopaedic surgery. The Author recommends that the mathematical model and the automated screwdriver are both further developed to prevent over-tightening and increase the speed and safety of screw insertion in surgery.