Patent ID: 7785330
Filing Date: 2010-08-31
Classification: A61B

Abstract:
1. A system for aligning a drill bushing with a transverse hole in an intramedullary nail, the system comprising: a probe having an elongated member with a distal end, a first permanent magnet that is polarized along its longitudinal axis that is mounted perpendicularly to the distal end of the elongated member; a second permanent magnet polarized along its longitudinal axis and mounted about the elongated member a predetermined distance away from the first permanent magnet, the second permanent magnet being oriented about the elongated member so that its longitudinal axis is parallel to the longitudinal axis of the first magnet; a targeting array of magnetic sensors, each magnetic sensor in the targeting array being arranged in a single plane, each magnetic sensor in the targeting array being configured to generate magnetic flux density measurements of a magnetic field of the first permanent magnet, each magnetic sensor in the targeting array has at least one corresponding sensor in the array that indicates a balance condition when the magnetic sensor and its corresponding magnetic sensor generate magnetic flux density measurements that are approximately equal; and an alignment sensor spaced apart from the targeting array by approximately the predetermined distance, the alignment sensor being configured to generate magnetic flux density measurements of a magnetic field of the second permanent magnet, the predetermined distance enabling the alignment sensor to measure the magnetic flux density of the magnetic field of the second permanent magnet without the magnetic flux density measurements being affected by the magnetic field of the first permanent magnet.