EP0523905A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Axial alignment of a drill guide
Assignee: Stryker Corp
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Filing: 1992-07-08
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Granted: —
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Expires: 2012-07-08
Abstract
Abstract The drill guide 16 for drill 28 is to be aligned with a transverse hole 26 in a femoral nail 21 located within a bone 12 so that when drilling holes in the bone the drill will pass cleanly through the hole 26. A coil 36 mounted within the nail 21 generates an alternating magnetic field along the axis of the hole 26. Two sensor discs 46 & 47 are axially spaced along the guide 16 and each carries four angularly spaced sensing coils 51-54 and 61-64 to determine when the centre of the disc 46 or 47 is in alignment with the axial magnetic field. Display units 81 and 82 show by means of LEDs 86-89 and 94-97 when there is any deviation from the required alignment, allowing the guide tube 41 to be correctly aligned for drilling.
Inventors
- 👤 Mehmet Rona
- 👤 Douglas J. Ely
- 👤 James A. Evans
- 👤 Matthew S. Alves
- 👤 Lisa D. Sertic
- 👤 Christopher D. Philipp
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-23 19:35
CPC Classifications
A; A61; A61B; A61B17/00; A61B17/16; A61B17/17; A61B17/1725; A61B17/1707; G; G01; G01B; G01B7/00; G01B7/30; G01B7/31; A61B90/00; A61B90/39; A61B2090/3954; A61B2090/3958; Y; Y10; Y10T; Y10T408/00; Y10T408/16; Y10T408/175; Y10T408/21; Y10T408/55; Y10T408/561; Y10T408/5623; Y10T408/56245; Y10T408/567; Y10T408/568
Claims Analysis
Total Claims: 48
Claim 1
Independent Claim
119 words
An apparatus comprising: a member having means defining an axis, and means for positioning an elongate part to extend along said axis, said means for positioning including first means on said member for facilitating generation of a magnetic field which changes in strength in directions radially away from said axis; sensor means for measuring the strength of said magnetic field at a plurality of locations spaced radially from and angularly about said elongate part; and second means responsive to said sensor means for detecting radial deviation of said elongate part in excess of a radial deviation limit from alignment with said axis and for providing an operator perceptible indication of a radial direction from said part to said axis.
Claim 2
Dependent Claim
126 words
An apparatus of Claim 1, wherein said sensor means includes first and second sensor arrangements supported at axially spaced locations on said elongate part, each said sensor arrangement measuring the strength of said magnetic field at a plurality of locations spaced radially from and angularly about said elongate part, and wherein said second means is responsive to each of said first and second sensor arrangements for detecting radial deviation of said elongate part in excess of said radial deviation limit from alignment with said axis in the region of either of said first and second sensor arrangements and for providing an operator perceptible indication of a radial direction from said part to said axis in the region of each of said first and second sensor arrangements.
Claim 3
Dependent Claim
71 words
An apparatus of Claim 2, wherein said first means includes an emitter coil provided on said member in coaxial alignment with said axis and means for applying to said emitter coil an electrical signal which causes said emitter coil to generate said magnetic field, and wherein each said sensor arrangement includes a respective detector coil at each of said plurality of locations where the strength of said magnetic field is measured.
Claim 4
Dependent Claim
53 words
An apparatus of Claim 3, wherein said electrical signal applied to said emitter coil is an AC signal at a predetermined frequency, and wherein each said sensor arrangement includes each said detector coil being connected in parallel with a respective capacitor to define a tank circuit which resonates substantially at said predetermined frequency.
Claim 5
Dependent Claim
85 words
An apparatus of Claim 3, wherein said detector coils of each of said first and second sensor arrangements are arranged in pairs, said coils of each said pair being disposed substantially on diametrically opposite sides of said elongate part, said second means reading and comparing field strength signals from said sensors of each said pair, and said second means providing said operator perceptible indication of a radial direction when said field strength signals from the coils of a given pair are different from each other.
Claim 6
Dependent Claim
75 words
An apparatus of Claim 5, wherein said second means calculates a field strength signal for one of said coils by dividing a difference between a current field strength value read from the coil and a zeroing field strength value read when the coil is free of the magnetic field by the difference between a calibration field strength value measured by the coil with the elongate part in axial alignment and said zeroing field strength value.
Claim 7
Dependent Claim
42 words
An apparatus of Claim 6, wherein said second means has means for generating each of said current field strength value, calibration field strength value and zeroing field strength value by summing five successive field strength readings from said one of said coils.
Claim 8
Dependent Claim
48 words
An apparatus of Claim 1, wherein said second means includes a plurality of selectively actuable light emitting devices provided at angularly spaced locations about a center point, said second means illuminating respective said light emitting devices to indicate respective said radial directions from said part to said axis.
Claim 9
Dependent Claim
35 words
An apparatus of Claim 8, including a further light emitting device in the region of said center point, said further light emitting device being illuminated when said elongate part is axially aligned with said axis.
Claim 10
Dependent Claim
24 words
An apparatus of Claim 1, wherein said second means includes means for generating an audible sound indicative of the magnitude of said radial deviation.
Claim 11
Dependent Claim
19 words
An apparatus of Claim 10, wherein said audible sound progressively decreases in frequency as said radial deviation progressively increases.
Claim 12
Dependent Claim
44 words
An apparatus of Claim 1, wherein each of said plurality of locations at which the strength of said magnetic field is measured lies substantially at a maximum gradient of the field strength of said magnetic field in a direction substantially radially of said axis.
Claim 13
Independent Claim
159 words
An apparatus for axially aligning a drill with a transverse hole in a member disposed in a body, comprising: means in said member for generating a magnetic field which has a maximum strength along an axis of said transverse hole and which decreases in strength in directions radially away from said axis; a drill guide having an axial drill opening therethrough, first and second sensor means provided at axially spaced locations on said drill guide and each having a plurality of sensors which are at angularly spaced locations and are spaced radially from said opening through said drill guide, and means responsive to said first and second sensor means for detecting a radial deviation of said drill opening in said drill guide in excess of a radial deviation limit from coaxial alignment with said axis of said hole in said member and for providing an operator perceptible indication of a radial direction from said drill opening to said axis.
Claim 14
Dependent Claim
29 words
An apparatus of Claim 13, wherein said drill guide has at an end nearest said member a plurality of sharp and angularly spaced projections extending axially toward said member.
Claim 15
Dependent Claim
35 words
An apparatus of Claim 13, wherein at an end of said drill guide remote from said member said drill opening is flared so as to diverge in diameter in a direction away from said member.
Claim 16
Dependent Claim
52 words
An apparatus of Claim 13, wherein said first and second sensor means each include a respective disk portion fixedly supported on said drill guide substantially perpendicular thereto, each said disk portion having on a side thereof facing said member a plurality of coils which are each a respective one of said sensors.
Claim 17
Dependent Claim
38 words
An apparatus of Claim 16, wherein said coils on said disk portion nearest said member are spaced from said drill opening by a smaller radial distance than said coils on said disk portion axially farthest from said member.
Claim 18
Dependent Claim
87 words
An apparatus of Claim 16, wherein said second means includes an L-shaped bracket having an outer end of a first leg fixedly secured to one of said disk portions, and spaced display parts fixedly connected to respective ends of a second leg of said bracket which extends approximately parallel to said drill guide, each said display part including a central first light emitting display device and including a plurality of second light emitting display devices provided at uniformly angularly spaced locations around said first light emitting device.
Claim 19
Dependent Claim
12 words
An apparatus of Claim 13, wherein said member is a femoral nail.
Claim 20
Dependent Claim
49 words
An apparatus of Claim 19, wherein said femoral nail is tubular, and wherein said member includes an elongate sleeve removably supported within said femoral nail, said means for generating said magnetic field including a coil supported on said sleeve in coaxial alignment with said transverse hole in said member.
Claim 21
Dependent Claim
28 words
An apparatus of Claim 20, wherein said coil has first and second portions which are coaxial with each other and are disposed on opposite sides of said sleeve.
Claim 22
Independent Claim
119 words
A method for axially aligning a drill guide for a drill with a transverse hole in a member disposed in a body, comprising the steps of generating a magnetic field which has a maximum strength along said axis of said transverse hole and which decreases in strength in directions radially away from said axis, sensing a strength of said field at a plurality of locations spaced angularly around and radially from a drill opening through a tubular drill guide, comparing respective field strengths detected by respective said sensors to detect a deviation of said drill opening from coaxial alignment with said axis, and providing an operator perceptible indication of a radial direction from said drill opening to said axis.
Claim 23
Dependent Claim
82 words
An apparatus of Claim 1, wherein said first means includes a sheet of nonconductive flexible material having thereon a plurality of spaced conductive coil portions and means connecting said coil portions in series, said sheet being rolled so that said coil portions are each coaxial to said axis, said coil portions collectively serving as an emitter coil, said first means further including means for applying to said emitter coil an electrical signal which causes said emitter coil to generate said magnetic field.
Claim 24
Dependent Claim
52 words
An apparatus of Claim 23, wherein said sheet has therein a plurality of first holes, each said coil portion approximately concentrically encircling one of said first holes, said first holes of said rolled sheet being concentric to said axis so as to collectively define a transverse radial opening through said rolled sheet.
Claim 25
Dependent Claim
75 words
An apparatus of Claim 24, wherein a plurality of said first holes are each encircled by a respective pair of said coil portions disposed on opposite sides of said sheet and each have adjacent thereto a second hole of smaller size, and including means for effecting an electrical connection between said coil portions of each said pair through the second hole which is adjacent the first hole encircled by the coil portions of the pair.
Claim 26
Dependent Claim
62 words
An apparatus of Claim 25, wherein said sheet is rolled spirally and has a subset of said first holes which are spaced along said sheet from said coil portions, and wherein portions of said rolled sheet having therein said first holes of said subset are disposed radially between portions of said sheet having therein said first holes with said coil portions therearound.
Claim 27
Dependent Claim
15 words
An apparatus of Claim 26, wherein each said coil portion has an approximately spiral configuration.
Claim 28
Dependent Claim
16 words
An apparatus of Claim 1, including manually operable means for selectively varying said radial deviation limit.
Claim 29
Dependent Claim
78 words
An apparatus of Claim 2, wherein said second means includes first display means for providing said operator perceptible indication for said first sensor arrangement in a first color, and second display means for providing said operator perceptible indication for said second sensor arrangement in a second color; and wherein said sensor means includes first and second portions which are respectively adjacent said first and second sensor arrangements and which are respectively said first color and said second color.
Claim 30
Dependent Claim
39 words
An apparatus of Claim 29, including a housing having therein said first and second sensor arrangements, said first and second display means being provided on said housing, and said first and second portions being respective portions of said housing.
Claim 31
Dependent Claim
55 words
An apparatus of Claim 8, including a plurality of further light emitting devices arranged at angularly spaced locations about said center point at approximately the same radial distance from said center point as said first-mentioned light emitting devices, said further light emitting devices being illuminated when said elongate part is axially aligned with said axis.
Claim 32
Dependent Claim
90 words
An apparatus of Claim 13, wherein said means for generating said magnetic field includes a sheet of nonconductive flexible material having thereon a plurality of spaced conductive coil portions and means connecting said coil portions in series, said sheet being rolled so that said coil portions are each coaxial to said axis, said coil portions collectively serving as an emitter coil, said means for generating said magnetic field further including means for applying to said emitter coil an electrical signal which causes said emitter coil to generate said magnetic field.
Claim 33
Dependent Claim
52 words
An apparatus of Claim 32, wherein said sheet has therein a plurality of first holes, each said coil portion approximately concentrically encircling one of said first holes, said first holes of said rolled sheet being concentric to said axis so as to collectively define a transverse radial opening through said rolled sheet.
Claim 34
Dependent Claim
75 words
An apparatus of Claim 33, wherein a plurality of said first holes are each encircled by a respective pair of said coil portions disposed on opposite sides of said sheet and each have adjacent thereto a second hole of smaller size, and including means for effecting an electrical connection between said coil portions of each said pair through the second hole which is adjacent the first hole encircled by the coil portions of the pair.
Claim 35
Dependent Claim
61 words
An apparatus of Claim 34, wherein said sheet is rolled spirally and has a subset of said first holes which are spaced along said sheet from said coil portions, and wherein portions of said rolled sheet having therein said first holes of said subset are disposed radially between portions of said sheet having therein said holes with said coil portions therearound.
Claim 36
Dependent Claim
15 words
An apparatus of Claim 35, wherein each said coil portion has an approximately spiral configuration.
Claim 37
Dependent Claim
16 words
An apparatus of Claim 13, including manually operable means for selectively varying said radial deviation limit.
Claim 38
Dependent Claim
76 words
An apparatus of Claim 13, wherein said second means includes first display means for providing said operator perceptible indication for said first sensor means in a first color, second display means for providing said operator perceptible indication for said second sensor means in a second color; and wherein said apparatus includes first and second portions which are respectively adjacent said first and second sensor means and which are respectively said first color and said second color.
Claim 39
Dependent Claim
39 words
An apparatus of Claim 38, including a housing having therein said first and second sensor means, said first and second display means being provided on said housing, and said first and second portions being respective portions of said housing.
Claim 40
Dependent Claim
103 words
An apparatus of Claim 13, wherein said second means includes a plurality of selectively actuable first light emitting devices provided at angularly spaced locations about a center point, said second means selectively illuminating respective said first light emitting devices to indicate respective radial directions from said drill opening to said axis, and including a plurality of second light emitting devices arranged at angularly spaced locations about said center point at approximately the same radial distance from said center point as said first light emitting devices, said second light emitting devices being illuminated when said drill opening is substantially axially aligned with said axis.
Claim 41
Dependent Claim
27 words
An apparatus of Claim 13, wherein said drill guide includes an elongate guide tube removably supported on said drill guide and having therethrough said axial drill opening.
Claim 42
Dependent Claim
96 words
An apparatus of Claim 41, wherein said member having said transverse hole is disposed in a bone of said body which is covered by a layer of tissue; wherein said drill guide includes a cylindrical sleeve, said guide tube having a first portion which is axially slidably inserted in said sleeve and has an outside diameter slightly less than the inside diameter of said sleeve, and having a second portion which extends axially outwardly from one end of said sleeve and has an axial length selected in proportion to the thickness of said layer of tissue.
Claim 43
Dependent Claim
25 words
An apparatus of Claim 42, wherein said second portion of said tube has an outside diameter approximately equal to the outside diameter of said sleeve.
Claim 44
Independent Claim
144 words
An apparatus comprising: a member having means defining an axis, and means for positioning an elongate part to extend along said axis, said means for positioning including first means on said member for generating a magnetic field, sensor means for measuring the strength of said magnetic field in the region of said elongate part, and second means responsive to said sensor means for detecting radial deviation of said elongate part in excess of a radial deviation limit from alignment with said axis and for providing an operator perceptible indication of a radial direction from said part to said axis, wherein said second means includes variable gain amplifier means for amplifying signals from said sensor means, and means for respectively increasing and decreasing the gain of said amplifier means when an output signal from said amplifier means is respectively below and above respective predetermined magnitudes.
Claim 45
Dependent Claim
45 words
An apparatus of Claim 44, wherein said second means includes means responsive to an increase or decrease of the gain of said amplifier means for thereafter inhibiting generation of said operator perceptible indication unless said output signal from said amplifier is within a predetermined range.
Claim 46
Dependent Claim
24 words
An apparatus of Claim 45, including means for generating an audible sound when said output signal of said amplifier means is outside said range.
Claim 47
Dependent Claim
34 words
An apparatus of Claim 44, wherein said second means includes means for changing the gain of said amplifier means between first and second gain values for effecting said increasing and decreasing of the gain.
Claim 48
Dependent Claim
136 words
An apparatus of Claim 47, wherein said sensor means includes first and second sensor arrangements supported at axially spaced locations on said elongate part, wherein said second means is responsive to each of said first and second sensor arrangements for detecting radial deviation of said elongate part in excess of said radial deviation limit from alignment with said axis in the region of either of said first and second sensor arrangements and for providing an operator perceptible indication of a radial direction from said part to said axis in the region of each of said first and second sensor arrangements, and wherein said second means includes means for suppressing said operator perceptible indication for one of said first and second sensor arrangements when said gain is set to the higher of said first and second values.
References Cited (Backward Citations)
No citation records indexed.
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