Northern Digital Inc.

Smith + Nephew

Kirsch, Stefan R.

Stefan R Kirsch

John M Nieminen

Christian J Schilling

Nicholas S Ritchey

Hans R Schild

Gene Edward Austin

Mark R Schneider

Nathaniel Kelley Grusin

Charles C Heotis

Hoa La Wilhelm

Georg Brunner

Vladimir F Kogan

Paul G Seiler

Nikolai Mikuszeit

Olaf Zerres

Ralph K Muench

Westley D Ashe

A system comprising: a sensor configured to be introduced into a clearance hole of a surgical implant, wherein the sensor is configured to be introduced in proximity to a generated magnetic field and cause distortion of the magnetic field; and one or more field measuring coils configured to: measure a characteristic of the magnetic field when the sensor is in proximity to the magnetic field; and provide, to a computing device, a signal representative of the measured characteristic of the magnetic field, wherein the computing device is configured to determine one or both of a position and an orientation of the sensor and the clearance hole based on the measured characteristic of the magnetic field.

Tracking a cylindrical opening

A field generator for use in a surgical targeting system is disclosed. The field generator includes a mounting structure including elements that are configured to receive components of an electromagnetic field generator. The elements are disposed on the mounting structure at locations and orientations relative to each other. The field generator includes at least one covering formed over the mounting structure, wherein, in use, the locations and orientations of the elements relative to each other remain substantially unaltered after exposure to one or more sterilization processes.

System and method for identifying a landmark

Targeting sensors for use in targeting landmarks of orthopaedic devices. The sensors include a non-cylindrical mounting platform such as a printed circuit board and at least two mounted or printed sensor coils to provide a low profile sensor assembly which can be placed in a predetermined position and orientation on or in an orthopaedic device. The platform has a non-circular cross-section having an aspect ratio of greater than about 1.5:1. The non-circular cross-section of the platform enables the sensor to be placed in a known fixed position within the implant. The sensor coils may be partially or fully embedded in the platform.

Targeting orthopaedic device landmarks

A distortion compensation method includes determining an undisturbed phase for at least one of a first position indication signal and a second position indication signal. The method includes determining an undisturbed ratio that relates the amplitude of the first position indication signal at a first frequency to the amplitude of the second position indication signal at a second frequency. The method also includes determining a disturbed amplitude of the position indication signal and adjusting a position indication based on the disturbed amplitude and phase, the undisturbed amplitude ratio, and the undisturbed phase. The method further comprises determining a relationship between the eddy current phase of the first position indication signal and the second position indication signal.

Eddy current detection and compensation

A system for determining the position, orientation and system gain factor of a probe includes a plurality of magnetic field sources and at least one magnetic field sensor, such that a combination of a magnetic field sensor and a magnetic field source generates a unique measured magnetic field value. The system includes a probe whose gain, position, and orientation affect these unique measured magnetic field values. A processor is configured to receive and iteratively process these unique measured magnetic field values to determine a system gain factor indicative of the gain of the probe and a plurality of location factors indicative of the position and orientation of the probe. The number of unique measured magnetic field values generated must be at least equal to the sum of the number of gain and location factors calculated.

Gain factor and position determination system

A method for determining the position of a sensor element which is used to measure a magnetic alternating field emitted by at least one generator unit. The sensor element receives a signal. Interference fields, which are the fields arising due to eddy currents generated in electrically conductive objects, are calculated. The eddy currents are calculated based on the alternating field. The position can be corrected based on the signal received in the sensor element.

Method for determining the position of a sensor element

A system for determining the position, orientation and system gain factor of a probe includes a plurality of magnetic field sources and at least one magnetic field sensor, such that a combination of a magnetic field sensor and a magnetic field source generates a unique measured magnetic field value. The system includes a probe whose gain, position, and orientation affect these unique measured magnetic field values. A processor is configured to receive and iteratively process these unique measured magnetic field values to determine a system gain factor and a plurality of location factors. The system gain factor is indicative of the gain of the probe, and the plurality of location factors are indicative of the position and orientation of the probe. The number of unique measured magnetic field values generated must be at least equal to the sum of the number of gain and location factors calculated.

A process detects distortions to magnetic location or orientation determinations. The process includes measuring a plurality of magnetic field values, determining one of a probe's location and a probe's orientation from an extremum of an optimization function. The measured values depend on the probe's location and orientation. The optimization function depends on the measured field values and field values calculated from a model. The process also includes indicating that a distortion to the determining exists in response to the extremum belonging to a preselected range.

Growing community of inventors

Radolfzell, Germany

Stefan R Kirsch