Percutaneous antegrade scaphoid screw placement: a feasibility and accuracy analysis of a novel electromagnetic navigation technique versus a standard fluoroscopic method

BackgroundCentral screw positioning in the scaphoid provides biomechanical advantages. MethodsA prospective randomized study of six fluoroscopically guided and six electromagnetically navigated screw (ENS) placements was performed on human cadavers. Accuracy of screw position was determined. Intraoperative fluoroscopy exposure times, readjustments of drilling directions, complete restarts and complications were documented. ResultsThe ENS method provided a mean time benefit of 7.34min compared with the standard method and the mean screw length ratio (SLR coronar: ENS 0.960.04mm, SFF: 0.92 +/- 0.04mm, P=0.065; SLR sagittal: ENS 0.98 +/- 0.02mm, SFF: 0.91 +/- 0.04mm, P=0.009) and the screw axis deviation angle (AD coronar: ENS 3.33 +/- 2.34 degrees, SFF: 10.33 +/- 2.58 degrees, P=0.002; AD sagittal: ENS 2.83 +/- 0.98 degrees, SFF: 11.00 +/- 6.16 degrees, P=0.002) were lower. Using the electromagnetic navigation procedure no drilling readjustments or restarts were required, no cortical breach occurred. ConclusionsCompared with the standard fluoroscopic technique, the ENS method used in this study showed higher accuracy, less complications, required less operation and radiation exposure time. Copyright (c) 2014 John Wiley & Sons, Ltd.