Method and device for locating magnetic implant source field
First Claim
1. A magnetic surgical implant comprising a flexible probe having a magnetic seed mounted at a distal end thereof and a magnetic field sensor mounted near the magnetic seed and in a fixed relationship thereto so that as an external magnetic field acts on said magnetic seed to guide or propel it through a patient'"'"'s body, the magnetic field sensor is also acted upon and provides an output which can be correlated with the position of the magnetic seed.
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Accused Products
Abstract
An apparatus and method for locating a magnetic implant in a surgical application using the field of a source magnet for the implant guiding field. The source magnet is an electromagnet having a separate calibrated magnetic field component in addition to the guiding field, so that both the magnitude and orientation of the magnetic field as a function of position around the magnet are known. A magnetic implant is provided with a sensor, such as a three-axis Hall effect sensor, to provide an indication of the magnitude and orientation of an applied magnetic field when the implant is surgically implanted in a patient. After implantation, the source magnet is energized with a current having a modulated component. The modulated component is received and filtered from the signal received from the Hall effect sensor in the implant, and provided to a processor that computes the location of the implant relative to the electromagnet based upon the detected magnitude and orientation of the modulated component of the magnetic field, and the location and orientation of the electromagnet. Localizers may be used to supply the relative locations of the patient and the electromagnet to the processor. A display may be provided to display a representation of the location of the implant in the patient, which may also be superimposed over a preoperative image of the patient.
194 Citations
20 Claims
- 1. A magnetic surgical implant comprising a flexible probe having a magnetic seed mounted at a distal end thereof and a magnetic field sensor mounted near the magnetic seed and in a fixed relationship thereto so that as an external magnetic field acts on said magnetic seed to guide or propel it through a patient'"'"'s body, the magnetic field sensor is also acted upon and provides an output which can be correlated with the position of the magnetic seed.
- 9. A device for providing position data for a magnetic surgical implant having a magnetic field sensor which is guided or propelled through a patient'"'"'s body by an external magnet, said device comprising a current source for supplying a modulated electrical current to the external magnet to thereby generate an oscillating magnetic field component, a demodulator coupled to the magnetic field sensor and responsive to a magnetic field direction and magnitude of the oscillating magnetic field component to provide a signal indicative of the oscillating magnetic field component at the location of the magnetic field sensor, a memory containing a representation of a relationship of spatial locations to a magnetic field pattern produced by the external magnet, and a data processor coupled to the demodulator and the memory and configured to compute a spatial location of the magnetic field sensor as a function of the signal indicative of the oscillating magnetic field component.
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16. A method for locating a magnetic surgical implant, comprising the steps of:
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(a) surgically implanting a magnetic implant including an associated magnetic field probe in a patient;
(b) applying a modulated magnetic field from an external electromagnet;
(c) detecting signals from the magnetic probe resulting from the application of the modulated magnetic field; and
(d) computing the relative location of the magnetic probe, and therefore, the magnetic implant, with respect to the electromagnet, from the detected signals from the magnetic probe. - View Dependent Claims (17, 18, 19, 20)
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Specification