Experimental Study and Preliminary Clinical Application of Mini-invasive Percutaneous Internal Screw Fixation for...

This study explored the feasibility of employing computer-aided design (CAD) and 3 dimensional (3D)-printed personalized guide plate for the mini-invasive percutaneous internal screw fixation of fractured scaphoid. The study consisted of two parts: (1) experimentation on upper limbs from corpses and (2) preliminary clinical application. Corpse experiments involved upper limbs of 6 adult corpses. The specimens of upper limbs were subjected to plain CT scan. Then the CT data were input into computer to conduct 3D reconstruction of wrist region. The direction and depth of the guide wire and screw were designed on the basis of the principle that screw should lie at the center of scaphoid and the long axis of the screw should be aligned with that of the scaphoid. The carpal bone model and the guide plate were designed and 3D-printed. By using the guide plates, the guide wire was placed and the cannulated compression screw was inserted. The wrist region was examined by X-ray and CT to observe the location of the screw in the scaphoid. The scaphoid was longitudinally excised to grossly observe the location and evaluate the result of screw insertion. For clinical application, the guide plate was employed in 4 patients with fresh scaphoid fracture using the aforementioned operative technique. Our results showed that, in the 6 corpse limbs, the guide plate well fitted the skin surface and the guide wire and screw were accurately put in place in one session. X-ray examination and gross observation confirmed that the screw was satisfactorily positioned and the result met the requirements of the preoperative design. For 4 patients, the guide wire and screw were all precisely inserted into place in one session. The operation time and X-ray exposure times were apparently reduced. The imaging examination exhibited satisfactory results and the hand functioned well. It was concluded that the operative guide plate used for the mini-invasive percutaneous internal screw fixation of fractured scaphoid not only can assist in accurate placement of screw but also shorten operation time and reduce insertion and X-ray exposure times, thereby reducing the radiation injury and damage to the substance and the blood circulation of carpal bone. Its use can also improve the learning curve of surgeons.