Novel Passive Two-Stage Magnetic Targeting Devices for Distal Locking of Interlocking Nails

Abstract

Interlocking nailing is a common surgical operation to stabilize fractures in long bones. One of the difficult parts of the surgery is how to locate the position and direction of a screw hole on the interlocking nail, which is invisible to the naked eye after insertion of the nail into the medullary canal. Here, we propose a novel two-stage targeting process using two passive magnetic devices to locate the position and direction of the screw hole without radiation for the locking screw procedure. This involves a ring-shape positioning magnet inside the nail to generate a magnetic field for targeting. From the accuracy test results of these two-stage targeting devices, the search region can be identified in less than 20 seconds by the 1st-stage targeting device, while the total targeting time to locate the drilling position and direction takes less than 4 minutes, with 100% successful rate in 50 attempts. The drilling test further combines the two-stage targeting process and drilling process on the swine tibia, and it is shown that a 100% successful rate is achieved in all 10 attempts, where the total time needed is less than 5 minutes.

Intramedullary Nail Holes Laser Indicator, a Non-Invasive Technique for Interlocking of Intramedullary Nails

“…Naked-eye 3D AR enables observation of the surgical path by costly and cumbersome equipment [24][25][26][27] . Electro-Magnetic (EM) and laser navigation systems can increase surgical accuracy without any X-ray exposure, but with excessive electrical noise causing large magnetic-eld distortion resulting in unstable tracking paths [28][29][30][31][32][33][34][35][36] . Moreover, the tracking accuracy is degraded with increasing distance of sensor and EM transmitter.…”

Passive Magnetic-Flux-Concentrator Based Electromagnetic Targeting System for Endobronchoscopy

“…Recently, we reported electromagnetic-induction-based methods for targeting/locating distal screw-hole in intramedullary interlocking-nail surgery [31,32,33,34,35]. The targeting method consists of a c-shaped electromagnet (which contains an emitting coil, a pick-up coil, and a c-shape silicon-steel frame), a modified intramedullary interlocking-nail (i.e., a high permeability silicon-steel sheet is fixed on the nail), and measurement electronics.…”