Electromagnetic apparatus and method for nerve localization during spinal surgery

摘要

An electromagnetic pedicle awl utilizes a tightly focused time-varying magnetic flux to create a localized electromotive force (EMF) near the tip. The localized EMF creates localized eddy currents in nearby nerves which excite ionic nerve channels, the excitation being detected by an electromyographic recording device. The awl only excites nerves directly in front of and directly to the side of the tip. The awl is comprised of a tapered awl or drill tip in combination with a solid core surrounded by a solenoid. A pulsed electric current source drives the solenoid to create a time-varying magnetic field in the vicinity of the tapered tip. The awl or drill tip may be stationary with respect to the solenoid or it may rotate. The awl in combination with an EMG detector connected to a patient is sensitive to the pedicle hole position with respect to adjacent nerves and reduces false placement failure.

主权项

1. A surgical awl tool for creating a pilot hole in muscle material proximate to a set of nerve fibers, the surgical awl tool capable of producing magnetic fields comprised of:
a solid core bushing; a tapered drill, having a drill tip and a cylindrical shaft, the cylindrical shaft resident in the solid core bushing so that a portion of the cylindrical shaft protrudes axially from the solid core bushing; the cylindrical shaft having a reverse thrust bearing attached near the tapered drill and set against the solid core bushing; the cylindrical shaft having a forward thrust bearing attached to the cylindrical shaft and set against an end of the solid core bushing so as not to allow lateral movement of the tapered drill with respect to the solid core bushing; a solenoid assembly for producing a magnetic field further comprised of a conductive coil of wire around the solid core bushing; an electric current source attached to the conductive coil of wire so that a time varying magnetic field is generated in a vicinity of the drill tip; and, a mechanism for detecting an excitation of the set of nerve fibers by the time varying magnetic field as the drill tip penetrates the muscle material.