Guide broche par impression 3D pour la fixation percutanée rétrograde du scaphoïde. Comparaison à la technique conventionnelle lors d’une étude cadavérique

Central screw placement in the scaphoid is the key of a rigid and safe percutaneous retrograde fixation of scaphoid fractures. Cannulated compression screws are most frequently used. This technique requires perioperative control of the position of the guide wire. The standard fluoroscopic method has many disadvantages: irradiation, multiple passes needed to obtain a proper position of the wire in two planes, and duration of the surgical procedure. The purpose of this study was to compare a patient-specific 3 dimensional-printed wire-guide (PS) and the standard fluroscopic technique (FT) in cadaver specimen. Twelve cadaver wrists were divided into two groups. In the FT group (6 wrists), the wire was inserted using the standard fluoroscopic method. In the PS group (6 wrists), a patient specific wire-guide was used. Preoperative CT scan allowed reconstruction of cutaneous envelope and identification of ideal path for the wire into the scaphoid. Based on these data, we modelized a “mold-guide”, including a wire guide sleeve aligned with the planned ideal path, and printed it using 3D-printing technology. Fluoroscopy was used in the latter group only to check the absence of prominence of the head screw. To assess the accuracy of screw placement in both groups, we analysed on postoperative CT scans the angular deviation of the screw with the ideal screw axis planned on preoperative CT scans (performed in both groups). Moreover, the operative time, the fluoroscopic time, and the number of trial guide wire placements were evaluated. The angular deviation between the screw position and the ideal screw axis was significantly lower in the PS group than in the FT group (respectively P  = 0.001 et P  = 0.02 for coronal and sagittal planes). The duration of procedure was significatively lower in the PS group (5.3 min) than in the FT group (17 min) ( P  = 0.007). Number of trial placements and fluoroscopic time were also significatively lower in the PS group. The use of a patient-specific 3D-printed guide for scaphoid percutaneous fixation allows a more accurate placement of the screw than with the standard fluoroscopic method. As several trial placements of the guide wire are not necessary, the operative time is decreased and the procedure is getting simpler. This new technique is promising and should be evaluated in clinical practice.