# US 2016/0249986 A1 · Surgical instrument and method for detecting the position of a surgical instrument > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2016/0249986 A1 - Document ID: US20160249986A1 - Status: Published application - Kind: A1 - Application number: 15/033,146 - Filed: 2014-10-31 - Published: 2016-09-01 - Earliest claimed: 2013-10-31 - Assignees: Fiagon AG Medical Technologies - Applicants: Fiagon AG Medical Technologies - Inventors: Timo KRÜGER; Dirk MUCHA - Web page: https://patentgrep.com/patent/US20160249986A1 ## CPC - A61B 34/20: Surgical navigation systems; Devices for tracking or guiding surgical instruments, e.g. for frameless stereotaxis - A61B 90/98: using electromagnetic means, e.g. transponders - A61B 2017/0046: {with a releasable handle; with handle and operating part separable} - A61B 2034/2051: {Electromagnetic tracking systems} - A61B 2034/2055: {Optical tracking systems} - A61B 2034/2063: {Acoustic tracking systems, e.g. using ultrasound} - A61B 2034/2072: {Reference field transducer attached to an instrument or patient} - A61B 2090/3983: {Reference marker arrangements for use with image guided surgery} - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) ## Abstract The invention relates to a surgical instrument with an instrument handle, an instrument shank connected to the instrument handle, an instrument tip with a work point, which instrument tip is connected to the instrument shank, and a first locator arranged on the instrument handle or the instrument shank. During a use of the surgical instrument, the instrument shank can be deflected, e.g. on account of transverse forces, at least between the first locator and the work point. A second locator is arranged at a distance from the first locator and, by comparison with the latter, closer to the work point, wherein the second locator is designed to detect five degrees of freedom. ## Claims ### Claim 1 A surgical instrument comprising an instrument handle, an instrument shaft connected to the instrument handle, an instrument tip which is connected to the instrument shaft and which has a work point, and a first locator arranged at the instrument handle or the instrument shaft, wherein the first locator is embodied to detect six degrees of freedom and is embodied as a position sensor and has two coils, and the instrument shaft is deflectable between the first locator and the work point during use of the surgical instrument and in that a second locator is arranged at a distance from the first locator and, compared with the latter, closer to the work point, wherein the second locator is embodied to detect only five degrees of freedom and is embodied as a position sensor and has one coil, wherein the second locator has smaller dimensions than the first locator. ### Claim 2 (depends on 1) The surgical instrument as claimed in claim 1, wherein the instrument handle and instrument shaft and/or instrument shaft and instrument tip are arrangeable against one another in a detachable manner, wherein the second locator is arranged in the instrument tip. ### Claim 3 (depends on 1) The surgical instrument as claimed in claim 1, wherein the second locator has a diameter of less than 0.5 mm, preferably less than 0.4 mm. ### Claim 4 (depends on 1) The surgical instrument as claimed in claim 1, wherein the first locator has at least one reflector for light waves and/or sound waves. ### Claim 5 (depends on 1) The surgical instrument as claimed in claim 1, wherein the instrument shaft has greater flexibility than the instrument handle. ### Claim 6 (depends on 1) The surgical instrument as claimed in claim 1, wherein the instrument tip has less flexibility between the second locator and the work point than in the remaining part of the instrument tip. ### Claim 7 (depends on 1) The surgical instrument as claimed in claim 1, wherein the surgical instrument has a memory unit for storing relative location data of the second locator relative to the first locator and/or for storing relative location data of the work point relative to the second locator and/or for storing relative location data of the work point relative to the first locator. ### Claim 8 (depends on 1) The surgical instrument as claimed in claim 1, wherein the second locator is arranged within an external contour of the surgical instrument. ### Claim 9 (depends on 1) The surgical instrument as claimed in claim 1, wherein the second locator is arranged in the surgical instrument at a distance of less than 2 cm from the work point. ### Claim 10 (depends on 1) The surgical instrument as claimed in claim 1, wherein the first locator and the second locator are arranged at the surgical instrument in such a way that a position detection system identifies the type of employed surgical instrument on the basis of characteristic values, provided to the position detection system, relating to surgical instruments and the respective arrangement of the first locator and the second locator at the surgical instrument. ### Claim 11 (depends on 1) A position detection system for establishing the position of surgical instruments, comprising an evaluation unit for establishing the position of locators arranged in the position detection system and a display unit for displaying the surgical instrument in its true position, and comprising a surgical instrument as claimed in claim 1. ### Claim 12 A method for detecting the position of a surgical instrument, wherein the instrument has an instrument handle, an instrument shaft which is connected to the instrument handle and which is deflectable during use of the surgical instrument, an instrument tip which is connected to the instrument shaft and which has a work point, and wherein a first locator is assigned to the instrument in a manner that is spatially defined at at least one instant and a second locator is arranged at the instrument in the vicinity of the instrument tip, wherein the second locator is embodied to detect five degrees of freedom, the method comprising the following steps: determining an instrument-specific calibration vector from the second locator to the work point in the coordinate system of the first locator in the case of a non-deflected instrument shaft, wherein the determination is preferably carried out initially; determining the location and direction of the work point in the reference coordinate system by transforming a current coordinate of the second locator, displaced by the calibration vector, into the coordinate system of the first locator, wherein the transformation is preferably carried out in each measurement cycle. ### Claim 13 (depends on 12) The method as claimed in claim 12, wherein the second locator supplies a location and the first locator supplies a direction for the transformation of the work point. ### Claim 14 (depends on 12) The method as claimed in claim 12, wherein the first locator is arranged at the instrument handle or the instrument shaft and the instrument shaft is deflectable between the first locator and the work point during use of the surgical instrument and wherein the second locator is arranged at a distance from the first locator and, compared with the latter, closer to the work pointer. ### Claim 15 (depends on 12) The method as claimed in claim 12, wherein the work point lies away from an instrument axis. ### Claim 16 (depends on 12) The method as claimed in claim 12, wherein the first locator is a patient locator, which is arranged separately from the instrument and securely on the patient. ### Claim 17 (depends on 12) The method as claimed in claim 12, wherein the first locator is a drill sleeve, which is arranged separately from the instrument and securely on the patient, wherein the instrument is insertable into the drill sleeve and the method further comprises the following step: establishing the location of the work point of the instrument by way of an insertion depth of the instrument into the drill sleeve. ### Claim 18 (depends on 12) The method as claimed in claim 12, further comprising the following steps: storing the calibration vector in a memory, in particular in an instrument memory, and determining the location and alignment of the work point in the reference coordinate system after reading out the calibration vector from the memory.