Cutting accessories for surgical cutting instruments

Abstract

Cutting accessories for surgical cutting instruments. The cutting accessory comprises a sensor assembly including at least one sensor coupled near the cutting tip of a tube assembly. The tube assembly may be straight, bent, rigid, or flexible. The sensor assembly may comprise a substrate coupled to an outer tube, having electrical wiring arranged in a twisted pair configuration. The sensor may be a coil sensor wound around an insulating spacer coupled to the distal region of the substrate. The coil sensor is electrically coupled to the electrical wiring. The flexible region of the substrate may traverse a bent or flexible region, and the electrical wiring may be in a linear configuration within the flexible region. The sensitivity of the coil sensor may be based on the properties of the tube assembly and / or the axial position of the coil sensor relative to the cutting tip.

Description

Technical Field

[0001] Claim of Priority This application claims priority and all benefits thereof to U.S. Provisional Patent Application No. 63 / 521,424, filed Jun. 6, 2023, the entire contents of which are incorporated herein by reference.

Background Art

[0002] Powered surgical cutting devices are widely prevalent in modern operating rooms and are used to excise almost any tissue type at almost any anatomical site. The form of the cutting device may in part be based on the ease of access to the tissue to be excised. In the case of procedures involving anatomically challenging structures such as the ear, nose, and throat (ENT), the shaft of the cutting device may include at least one bend or curvature. The bend may be rigid at a fixed angle or may be selectively adjustable through articulation or manual bending of the shaft. A rigid bend often requires selecting the desired cutting instrument from a list of cutting tools and, thus, does not readily allow the surgeon to make adjustments in situ during the surgical procedure.

[0003] Of particular interest is the tracking and navigation of cutting tools, more specifically, the cutting tips of angled cutting tools. Accurate tracking is essential to provide users with highly accurate information about the location of the cutting tip relative to delicate anatomical structures such as the orbit, carotid artery, and optic nerve. Current solutions have drawbacks. For example, U.S. Patent Publication 2010 / 0234724, published on September 16, 2010, incorporated by reference, discloses a clamp including a sensor for electromagnetic (EM) tracking. This clamp can be detachably coupled to the proximal portion of a shaft adjacent to a hub. This solution requires the provision of separate components and therefore necessitates cumbersome assembly and calibration before the commencement of surgical procedures. Furthermore, the size of the clamp obstructs the line of sight, and placing the clamp proximal is generally incompatible with non-rigid shafts. Another example is disclosed in U.S. Patent Publication No. 2020 / 0107885, published on April 9, 2020, incorporated by reference, in which a position sensor is located near the cutting tip of a shaver. However, the distal end of the cutting tip is typically rounded, and the cutting window is located proximal to the distal end. As a result, the rounded shape may distort the perception of the tracking point when displayed on a monitor, which may lead to inaccuracies in tissue excision. Therefore, there is a need in the art to enable improved and accurate tracking of the features of the cutting tip on a cutting attachment that can be detachably coupled to a main handpiece and / or on which the shaft is selectively adjustable through manual bending. It is also desirable to enable rotation of the cutting window on an articulated or bendable tube assembly. [Overview of the project]

[0004] This disclosure pertains to cutting accessories for surgical cutting instruments. Cutting accessories facilitate intuitive and precise navigation of the cutting tip. A sensor assembly includes a sensor positioned near the cutting tip and, in certain embodiments, distal to the bend and / or malleable region. Thus, the position of the sensor relative to the cutting tip remains fixed regardless of whether the bend is altered or reoriented. In addition, cutting accessories with longer axes can be tracked more accurately. The sensor assembly is designed to reduce susceptibility to electromagnetic noise from, for example, a motor located within the handpiece. The advanced functionality described below is incorporated into cutting accessories that can be detachably coupled to the handpiece. Further advantages of the cutting accessories will be readily apparent in light of the description and accompanying figures.

[0005] The cutting attachment includes a hub and a tube assembly extending distally from the outer hub. The tube assembly includes an outer tube, a drive shaft, and optionally an intermediate tube. The cutting tip is located at the distal end of the drive shaft. The cutting tip is a sharp or toothed end (edge) rotatably positioned within the cutting window. The drive shaft may be an inner tube defining a suction lumen. Alternatively, a bur head may be coupled to the drive shaft or inner tube. The tube assembly may be straight, angled, or malleable. The drive shaft includes at least one malleable region configured to transmit torque through a bend or flexible region.

[0006] The cutting accessory includes a sensor assembly having at least one sensor positioned near the cutting tip. The sensor may be a coil sensor. The sensor is positioned distal to the bend or flexible region such that the sensor is adjacent to or near the cutting tip. The sensor assembly includes a substrate and electrical wiring. The substrate is coupled to an outer tube and extends along the outer tube. The substrate may extend along the underside of the outer tube and traverse the convex side of the bend. The sensor is positioned in a fixed spatial relationship to a predetermined point on the cutting tip or a feature portion of the cutting tip. The sensor is configured to generate an electrical signal in response to an electromagnetic (EM) field, the electrical signal indicating the position of the cutting tip in three-dimensional space.

[0007] The coil sensor may be coaxially positioned around the outer tube. The coil sensor may be a 5-degree-of-freedom (DOF) sensor with a wire, such as copper wire, wound around it. The coil sensor has a sensor axis aligned with the axis of the tube assembly at the cutting tip. In a non-limiting example, the wire is 48-60 AWG (US wire gauge) and ranges from approximately 300-2,200 turns, more specifically from approximately 400-600 turns. The resulting coil sensor thickness is approximately 0.25 millimeters. Furthermore, the number of turns may be designed to give the desired sensitivity of the sensor assembly, influenced by the properties of the tube assembly. The sensitivity of the sensor assembly may be adjusted in part based on the axial position of the coil sensor on the outer tube.

[0008] The substrate may be formed from a polymer such as polyimide (PI) or other suitably flexible material. The substrate may be elongated and include a proximal region, a flexible region, and a distal region. The flexible region may be narrower than the proximal and / or distal regions. The flexible region is axially aligned with the bend or flexibility region of the tube assembly. The proximal region is positioned between the flexible region and the hub of the cutting accessory. The distal region is distal to the flexible region and is positioned near or adjacent to the cutting tip.

[0009] A pair of electrical wires extends along the length of the circuit board. The electrical wires are arranged in a twisted pair configuration. The twisted pair configuration may include a first electrical wire and a second electrical wire, in which case vias allow these wires to be arranged alternately on opposite sides of the circuit board. Each electrical wire is placed in complementary linear sections on opposite sides of the circuit board, the upper and lower surfaces, separated by vias. The twist pitch may be approximately 2.3 to 3.3 millimeters, or more specifically, approximately 2.8 millimeters.

[0010] The twisted pair configuration may be located within or extending along the proximal region of the substrate. The linear configuration may be located within or extending along the flexible region of the substrate. The linear configuration may include each electrical wire being arranged as a complementary linear path on the opposite upper and lower surfaces of the substrate. The second twisted pair configuration may be located near the distal sensor relative to the linear configuration.

[0011] The sensor assembly includes a coil pad located in the distal region of the substrate and formed from a conductive material. Electrical wiring is electrically coupled to the coil pad. The sensor is coupled to the coil pad to provide electrical communication between the sensor and the electrical wiring. One coil pad may be located on the upper surface of the substrate, and the other coil pad may be located on the lower surface of the substrate. The sensor assembly further includes a proximal pad located in the proximal region of the substrate and formed from a conductive material. Electrical wiring is electrically coupled to the proximal pad. Within a hub, the sensor cable may be electrically coupled to the proximal pad. Alternatively, a wireless transceiver may be electrically coupled to the proximal pad and configured to transmit data to a wireless receiver in a navigation system.

[0012] The sensor assembly may include an insulating spacer bonded to a substrate and coaxially positioned around an outer tube. The insulating spacer is a tubular compartment formed from a polymer such as polyimide. The coil sensor is wound around the insulating spacer. The substrate is bonded to the insulating spacer. The insulating spacer is coaxially positioned around the outer tube, and the coil sensor is coaxially positioned around the insulating spacer. An insulating layer or sheath may be coaxially positioned around the coil sensor, substrate, and electrical wiring. The sheath may extend from above the coil sensor proximal to a position near or inside the hub. The sheath may be a heat-shrinkable material, a polymer sheath fixed to the outer tube, etc.

[0013] The cutting attachments enable ergonomic handling and operation, including rotation of the cutting window. Rotation of the cutting window may be performed via an actuator operably coupled to the tube assembly. For improved ergonomics, the actuator may be a dial operably coupled to the crown or upper side of the outer hub and oriented distally at an acute angle with respect to the longitudinal axis of the tube assembly. Other modifications are disclosed herein.

[0014] Accordingly, according to a first aspect of the present disclosure, the cutting accessory includes a hub configured to be detachably coupled to a handpiece of a powered surgical instrument. An outer tube extends from the hub, and a drive shaft is coaxially and rotatably arranged within the outer tube. A cutting tip is located at the distal end of the drive shaft. A sensor assembly is configured to be electronically communicative with a navigation system. The sensor assembly includes a substrate coupled to and extending along the outer tube. The substrate has a flexible region and a proximal region between the flexible region and the hub. Electrical wiring extends along the substrate. The electrical wiring is arranged in a twisted pair configuration in the proximal region and in a linear configuration in the flexible region. A coil sensor is located coaxially around the outer tube between the flexible region and the cutting tip. The coil sensor communicates electrically with the electrical wiring. The coil sensor is configured to detect changes in the electric field induced by the navigation system.

[0015] According to a second aspect of the present disclosure, the cutting accessory includes a hub configured to be detachably coupled to a handpiece of a powered surgical instrument. An outer tube extends from the hub. A drive shaft is coaxially and rotatably arranged within the outer tube. A cutting tip is located at the distal end of the drive shaft. A sensor assembly is configured to be electronically communicative with a navigation system. The sensor assembly includes a substrate coupled to and extending along the outer tube, and electrical wiring extending along the substrate. A coil sensor includes a conductive wire coaxially wound around the outer tube and positioned proximal to a calibrated distance from the feature portion of the cutting tip. The coil sensor communicates electrically with the electrical wiring. The coil sensor is configured to detect changes in the electric field induced by the navigation system. A sheath may be coaxially arranged around the substrate and the coil sensor.

[0016] According to a third aspect of the present disclosure, the cutting accessory includes a hub configured to be detachably coupled to a handpiece of a powered surgical instrument. An outer tube extends from the hub, and a drive shaft is coaxially and rotatably positioned within the outer tube. A cutting tip is positioned at the distal end of the drive shaft. A sensor assembly is configured to be electronically communicative with a navigation system. The sensor assembly includes a substrate coupled to and extending along the outer tube, and electrical wiring extending along the substrate. An insulating spacer is coupled to the substrate and positioned coaxially around the outer tube. A coil sensor is positioned coaxially around the insulating spacer. The coil sensor communicates electrically with the electrical wiring. The coil sensor is configured to detect changes in the electric field induced by the navigation system.

[0017] According to a fourth aspect of the present disclosure, the cutting accessory includes a hub configured to be detachably coupled to a handpiece of a powered surgical instrument. An outer tube extends from the hub and includes a bend or flexible region. A drive shaft is coaxially and rotatably positioned within the outer tube. The drive shaft is configured to transmit torque through the bend or flexible region. A cutting tip is positioned at the distal end of the drive shaft. A sensor assembly is configured to be electronically communicative with a navigation system. The sensor assembly includes a substrate coupled to and extending along the outer tube. The substrate has a proximal region and a flexible region. The width of the flexible region is less than the width of the proximal region, and at least a portion of the flexible region of the substrate is aligned with the bend or flexible region of the outer tube. Electrical wiring extends along the substrate. A coil sensor is coaxially positioned around the outer tube between the flexible region and the cutting tip. The coil sensor communicates electrically with the electrical wiring. The coil sensor is configured to detect changes in the electric field induced by the navigation system.

[0018] According to a fifth aspect of the present disclosure, the cutting accessory includes a hub configured to be detachably coupled to a handpiece of a powered surgical instrument. An outer tube extends from the hub, and a drive shaft is coaxially and rotatably positioned within the outer tube. A cutting tip is positioned at the distal end of the drive shaft. A sensor assembly is configured to be electronically communicative with a navigation system. The sensor assembly includes a coil sensor coaxially positioned around the outer tube. The coil sensor is formed from gauge wire and number of turns to provide sensor sensitivity that compensates for the material properties of the outer tube and the drive shaft.

[0019] According to a sixth aspect of this disclosure, a method for assembling a cutting accessory includes the steps of preparing an insulating tube or cutting an insulating tube to a length corresponding to the design length of a coil sensor. Conductive wires are wound around the insulating tube to form a coil sensor. A substrate is prepared, including electrical wiring coupled to the substrate. The insulating tube is fixed to the substrate. Electrical communication is established between the coil sensor and the electrical wiring on the substrate. The insulating tube and the coil sensor are coaxially oriented so as to be positioned on the outer tube of the cutting accessory. The substrate is fixed to the outer tube. A sheath may be heat-shrinked coaxially around the substrate and the coil sensor. [Brief explanation of the drawing]

[0020] [Figure 1] This is a perspective view of a powered surgical cutting instrument. One embodiment of the cutting accessory is detachably coupled to the handpiece. The cutting accessory includes an outer hub, a tube assembly extending from the outer hub, and a sensor assembly coupled to the tube assembly. [Figure 2] Figure 1 is a perspective view of the cutting accessory. [Figure 3] Figure 1 is a lower perspective view of the cutting accessory. [Figure 4] Figure 1 is an exploded view of the cutting accessories. [Figure 5] This is a cross-sectional elevation view of the cutting accessory shown in Figure 2, taken along line 5-5. [Figure 6] Figure 5 shows a detailed view of the cutting accessory tip located within circle 6-6. [Figure 7] This is a plan view of the circuit board of the sensor assembly. [Figure 8] Figure 7 shows a detailed view of a portion of the circuit board of the sensor assembly within circle 8-8, illustrating the twisted-pair configuration of the electrical wiring. Details A and B in Figure 8 each show one of the electrical wires, respectively. [Figure 9A] This is a schematic diagram of a first modified example of the placement of the sensor assembly on the tube assembly. [Figure 9B] This is a schematic diagram of a second modified example of the placement of the sensor assembly on the tube assembly. [Figure 10] A schematic view of a third modification of the arrangement of the sensor assembly to the tube assembly, where the twisted pair configuration is positioned distally relative to the straight configuration of the electrical wiring. [Figure 11] A view showing a method of assembling an embodiment of a cutting accessory illustrated and described herein. [Figure 12] A perspective view of a powered surgical cutting instrument. One embodiment of the cutting accessory is removably coupled to the handpiece. The cutting accessory includes an outer hub and a tube assembly extending from the outer hub. [Figure 13] A rear perspective view of the cutting accessory. [Figure 14A] A detailed view of the tube assembly of FIG. 13 within circle 14A modified to represent a first modification of the sensor. [Figure 14B] A detailed view of a modification of the tube assembly of FIG. 13 within circle 14B modified to represent a second modification of the sensor. [Figure 15] A cross-sectional elevation view of the cutting accessory of FIG. 13 taken along section line 15-15. [Figure 16] An exploded perspective view of a cutting accessory including an outer hub, a tube assembly, and an electrical bridge. [Figure 17] A front perspective view of one embodiment of the electrical bridge. [Figure 18] A rear perspective view of the electrical bridge of FIG. 17. [Figure 19] A perspective view of another embodiment of the electrical bridge. [Figure 20] A perspective view of a powered surgical cutting instrument having another embodiment of a cutting accessory removably coupled to the handpiece. A sensor cable extends from the cutting accessory. [Figure 21] An exploded cross-sectional view of another embodiment of the cutting accessory. [Figure 22] A perspective view of another embodiment of the electrical bridge. [Figure 23]This diagram shows a navigation system including a processor, electric field generator, and display. The cutting machine is used in conjunction with the navigation system and display to provide real-time navigation guidance. [Figure 24] This is a diagram illustrating an example output of real-time navigation guidance. [Figure 25] This is a diagram showing the visualization options available on the display. [Figure 26] This is a partial perspective view of one embodiment of a cutting tip, in which the tip shape includes a pointed tip that provides a tracking point configured to be calibrated by a navigation sensor. [Figure 27] Figure 26 is an axial view of the cutting chip. [Figure 28] This is a cross-sectional view of the cutting chip shown in Figure 26, taken along the cross-sectional line 28-28. [Figure 29] This is a perspective view of another embodiment of a cutting accessory, in which the cutting tip includes a bar head positioned adjacent to the hood. [Figure 30] Figure 29 is a top plan view of the cutting chip. [Figure 31] Figure 29 is an elevation view of a cutting chip. [Figure 32] Figure 29 is a partially exploded view of the cutting accessories. [Figure 33] This is a detailed view of the sensor assembly in Figure 32, located within Circle 33-33. [Figures 34A-34D] This is a diagram illustrating an embodiment of an actuator for rotating a cutting window. [Modes for carrying out the invention]

[0021] Figure 1 shows a surgical cutting instrument 40, which includes a handpiece 42 and a cutting attachment 44 configured to be detachably coupled to the handpiece 42. The handpiece 42 is the main component, i.e., a component that is sterilized and configured to be reused over multiple surgical procedures. The cutting attachment 44 may be discarded after a single use, or it may also be manufactured to be sterilizable and reusable. Alternatively, the handpiece 42 and the cutting attachment 44 may be integrally formed and not detachable from each other. The handpiece 42 is shaped to be ergonomically suitable for gripping and handling. The handpiece 42 includes a power port or power cord 46, a suction port 48, and optionally a cleaning port 50. A motor (not shown) in the handpiece 42 is driven by power transmitted through the power cord 46, which is configured to be detachably coupled to a power source 52 ( schematically shown in Figure 23). The power supply 52 may be a surgical console, for example, a powered instrument driver sold by Stryker Corporation (Kalamazoo, Michigan) under the trade name CORE. The suction port 48 is configured to removably house a suction tube to establish a suction path with a suction source 54 (Schematically shown in Figure 23), and the suction tube is configured to be removably coupled to the suction source. One preferred suction source is provided in a waste fluid management system sold by Stryker Corporation under the trade name Neptune. In one embodiment, the wash port 50 is configured to removably house a wash tube to establish a wash path with a wash fluid supply source 56 (Schematically shown in Figure 23). A wash pump (not shown) is configured to guide the wash fluid through the handpiece 42 and cutting accessories 44 and discharge it to the surgical site. The suction source 54 and / or wash pump may be integrated into the surgical console. The suction and cleaning pathways of the surgical cutting instrument 40 may be at least similar to those disclosed in International Publication WO2021 / 224862, owned by the applicant, published on November 11, 2021, and International Publication WO2022 / 123535, owned by the applicant, published on June 16, 2022, with the entire contents of each document incorporated by reference.

[0022] The cutting attachment 44 includes a hub, also referred to herein as an outer hub 58. The handpiece 42 and the outer hub 58 of the cutting attachment 44 include a complementary coupling mechanism (not identified) for releasably securing the cutting attachment 44 to the handpiece 42. This coupling mechanism may be a latch or other suitable interlocking structure, e.g., one disclosed in International Publication No. WO2021 / 224862 as described above. The handpiece 42 may include a drive hub 62 that defines at least one opening or cavity 60 and is configured to guide the cutting attachment 44 into the cavity 60. The drive hub 62 is rotatably positioned within the outer hub 58. The drive hub 62 includes at least one spline or interface structure configured to operably couple to a motor and the outer hub 58 which is coupled to the handpiece 42. To create a tight flow connection between the outer hub 58 and the handpiece 42 for delivering the cleaning fluid through the cavity 60 into an annular space defined between the drive hub 62 and the outer hub 58, the seal 65 may be coupled to the outer hub 58 or located inside the outer hub 58.

[0023] Referring further to Figures 2 to 6, the tube assembly 64 extends distally from the outer hub 58. The tube assembly 64 includes an outer tube 66, a drive shaft 68 (also referred to herein as the inner tube), and optionally an intermediate tube 70 (see Figure 15). The outer tube 66 is coupled to the outer hub 58, and the intermediate tube 70 is rotatably and coaxially positioned within the outer tube 66. The drive shaft 68 is rotatably and coaxially positioned within the intermediate tube 70 and is coupled to the drive hub 62. A cutting tip 72 is present at the distal end of the drive shaft 68. In embodiments where the cutting accessory 44 is a microdebrider / shaver, the drive shaft 68 is the inner tube defining a suction lumen, and the cutting tip 72 is a sharp or toothed end (edge) positioned on this inner tube. The outer tube 66 or the intermediate tube 70 may define a cutting window 74 in which the inner tube rotatably operates. As a result, with the drive hub 62 operably coupled to the motor, the motor rotates the inner tube, cutting or removing tissue in the cutting window 74 with its toothed end. The excised tissue is aspirated through the cutting window 74 and enters the suction lumen. In embodiments where the cutting accessory 44 is a bur, the bur head may be coupled to the drive shaft 68 or the inner tube and extend beyond the distal end of the outer tube 66. The bur may be a diamond bur, a grooved bur, or any other suitable type and size of bur head. Furthermore, aspects of the present invention may be used in other cutting instruments such as scrapers, files, cutting edges, trephines, brushes, or in non-cutting manual or powered devices such as screwdrivers, endoscope cameras, lighting assemblies, and suction devices.

[0024] The tube assembly 64 may be straight, angled, or flexible. An angled or flexible variation of the tube assembly 64 may include at least one bend 76 or at least one bendable or flexible region 78 (see Figure 12). The drive shaft 68 includes at least one flexible region 80 (see Figure 6) corresponding to the axial position of at least the bend 76 or flexible region 78. The flexible region 80 of the drive shaft 68 is configured to follow a shaped configuration maintained by the outer tube 66 and to transmit torque through the bend 76. The flexible region 80 may be achieved in several suitable ways, such as those disclosed in International Publication No. WO2022 / 123535 mentioned above. In one example, the flexible region 80 includes castellated sections that interlock to define slots. The interlocking of the sections is configured to transmit torque as the drive shaft 68 is rotated by a motor. Additionally, or alternatively, the drive shaft 68 may have helical, spiral, wound, or braided characteristics configured to transmit torque around the bend 76 of the tube assembly 64 in a shaped configuration. Furthermore, the tube assembly 64 may be modified to be articulated by preferred means, for example, those disclosed in U.S. Patent Publication No. 2018 / 0242962, published on August 30, 2018, owned by the applicant, the entire contents of which are incorporated by reference.

[0025] In a two-tube configuration providing suction and cleaning, a first liner (not shown) may be coupled to the outer tube 66 and positioned to cover the slots, preventing leakage of cleaning fluid through the slots of the outer tube 66. The first liner may be a heat-shrinkable pipe positioned on the outer surface of the outer tube 66, or a tubular sheath coupled to the outer or inner surface of the outer tube 66. Similarly, a second liner (not shown) may be coupled to the flexible region 80 of the drive shaft 68 and positioned on or within the flexible region 80. In embodiments where an intermediate tube 70 is present, the intermediate tube 70 also includes at least one flexible region (not identified) corresponding to the axial position of at least the bend 76 or flexible region 78 and the axial position of the flexible region 80 of the drive shaft 68. A third liner (not shown) may be provided and coupled to the flexible region of the intermediate tube 70 and positioned on or within the flexible region.

[0026] Navigation of surgical instruments is becoming common in modern operating rooms. Known devices capable of navigation often require a relatively large sensor unit to be positioned on or near the handpiece, outside the anatomical structure where the cutting tip is located. Such solutions result in suboptimal accuracy, particularly with long tube assemblies and / or cutting instruments with bends along the length of the tube assembly. Furthermore, such solutions are incompatible with the in-situ adjustments provided by flexible surgical instruments. In other words, known devices require reconfiguration of the navigation software each time the tube assembly is bent or bent again, which is undesirable.

[0027] The cutting accessory 44 of this disclosure overcomes such drawbacks by including a sensor assembly 82 in which at least one sensor 84 is positioned near the cutting tip 72. More specifically, the sensor 84 is positioned distal to the bend 76 or flexible region 78 such that the position of the sensor 84 relative to the cutting tip 72 is stationary (fixed). Furthermore, because the sensor 84 is adjacent to or near the cutting tip 72, excellent accuracy is possible. Moreover, the configuration of the sensor assembly 82 is minimal in size to provide a navigation-enabled device with an appearance and workflow similar to surgical instruments familiar to surgeons, while maintaining a line of sight to the cutting tip 72 (for example, in endoscopic procedures).

[0028] Figures 1 to 6 show a coil sensor 84. The sensor assembly 82 further includes a substrate 86 and electrical wiring 88. The substrate 86 is coupled to the outer tube 66 and extends along the outer tube 66. For example, Figure 3 shows a strip-shaped substrate 86 that extends along the underside of the outer tube 66 and traverses the convex side of the bend 76. In alternative embodiments where the tube assembly 64 is flexible, the substrate 86 may be positioned to extend along the flexible spine of the flexible region (i.e., between the slotted portions on opposite sides of each other). The sensor 84 is coupled to the substrate 86 at a position distal to the bend 76. In a manner to be described later, the sensor 84 is positioned in a fixed spatial relationship with respect to a predetermined point or feature (e.g., the most distal point) of the cutting tip 72. The sensor 84 is configured to generate an electrical signal in response to an electromagnetic (EM) field, which indicates the position of the cutting tip 72 in three-dimensional space. In other words, the sensor 84 is configured to detect changes in the electric field induced by the electric field generator 158 of the navigation system 154 (see Figure 23).

[0029] A preferred embodiment of the sensor is a coil sensor 84 coaxially positioned around the outer tube 66. Alternatively, the coil sensor 84 may be coaxially positioned within or between the drive shaft 68 of the tube assembly 64 and the outer tube 66. The coil sensor 84 may be a 5-degree-of-freedom (DOF) sensor, around which a wire such as copper wire is wound and optionally coated with a preferred coating such as Parlene. As a result, the coil sensor 84 has a sensor axis aligned with the axis of the tube assembly 64 at the cutting tip 72. In a non-limiting example, the wire is 48–53 AWG (US wire gauge) and ranges from approximately 300–2,200 turns, more specifically from approximately 400–600 turns. In this configuration, the net increase in the diameter of the tube assembly 64 is small, at 0.5 millimeters. Here again, this minimizes the impact on the surgeon's line of sight, while allowing the coil sensor 84 to be positioned close to the cutting tip 72 for superior accuracy. The number of turns may be designed to give the desired sensitivity of the sensor assembly 82, which is influenced by the properties of the tube assembly 64 (i.e., size, material, etc.). In one example, the sensitivity of the sensor assembly 82 is in the range of approximately 0.060 to 0.150 V / Hz / T, more specifically, in the range of approximately 0.071 to 0.106 V / Hz / T, which is reduced by approximately 35% to compensate for the properties of the tube assembly 64. Furthermore, the sensitivity of the sensor assembly 82 may also be adjusted in part based on the axial position of the coil sensor 84 on the outer tube 66. For example, the sensitivity may be reduced by a greater amount the closer the coil sensor 84 is to the cutting tip 72.

[0030] The substrate 86 may be formed from a polymer such as polyimide (PI) or another preferably flexible material. Referring further to Figure 7, the substrate 86 may be elongated and include a proximal region 90, a flexible region 92, and a distal region 94. The flexible region 92 may be narrower than one or both of the proximal region 90 and the distal region 94. In one example, the width of the flexible region 92 is 2 millimeters or less, the width of the proximal region 90 is 3 millimeters or less, and / or the width of the distal region 94 is 4 millimeters or less. These dimensions are illustrative and may be sized to correspond to the dimensions of the tube assembly 64. The flexible region 92 is axially aligned with the bend 76 or flexible region 78 of the tube assembly 64. The narrow width of the flexible region 92 allows for sufficient bending when bending, preventing twisting when the sensor assembly 82 is coupled to the bend 76 and / or when the flexible region 78 is repeatedly bent. The proximal region 90 of the substrate 86 is proximal to the flexible region 92, and more specifically, is located between the flexible region 92 of the cutting accessory 44 and the outer hub 58. The distal region 94 of the substrate 86 is distal to the flexible region 92, and more specifically, is located near or next to the cutting tip 72.

[0031] A pair of electrical wirings 88 extends along the length of the substrate 86. Referring again to Figure 7, and further to Figures 8A and 8B, these electrical wirings 88 are arranged in a twisted pair configuration (TWP). The twisted pair configuration may include a first electrical wiring 88a and a second electrical wiring 88b, where vias 96 alternately arrange the wirings 88a and 88b on opposite sides of the substrate 86. In other words, each of the electrical wirings 88a and 88b is arranged in complementary linear sections on the upper and lower surfaces of the substrate 86, which face opposite each other, separated by vias 96, with each electrical wiring 88a and 88b routed between the upper and lower surfaces. A preferred structure of the twisted pair configuration is also disclosed in U.S. Patent No. 5,646,368, issued on July 8, 1997, the entire contents of which are incorporated by reference. Among the various advantages, routing the electrical wiring 88 in a twisted pair configuration minimizes susceptibility to external electromagnetic noise, maximizes coupling between the electrical wiring 88, and prevents radiation. The twist pitch, i.e., the spacing between vias 96, may be designed to provide the maximum number of twists relative to the length of the substrate 86, taking into account the additional cost and the possibility of the vias 96 rupturing under mechanical stress and strain. In exemplary embodiments, the spacing between vias 96 is approximately 2.3 to 3.3 millimeters, more specifically approximately 2.8 millimeters.

[0032] As shown in Figure 7, the twisted pair configuration may be located in or extending along the proximal region 90 of the substrate 86. The linear configuration (LC) may be located in or extending along the flexible region 92 of the substrate 86. As mentioned, vias 96 are typically not suitable for bending. Therefore, the linear configuration conveniently accommodates such bending, while allowing the twisted pair configuration along most of the length of the sensor assembly 82. The linear configuration may include the arrangement of electrical wirings 88a and 88b in complementary linear paths on the upper and lower surfaces of the substrate 86, facing opposite directions from each other. Figure 10 shows another configuration in which the second twisted pair configuration may be located distal to the linear configuration and closer to the sensor 84.

[0033] The sensor assembly 82 includes a distal pad, also referred to herein as a coil pad 98. The coil pad 98 is located in the distal region 94 of the substrate 86 and is formed from a conductive material. Electrical wiring 88 is electrically coupled to the coil pad 98, for example, by soldering or other preferred bonding means. More specifically, as best shown in Figure 10, one electrical wire 88a is coupled to one coil pad 98 and the other electrical wire 88b is coupled to the other coil pad 98. Furthermore, the sensor 84 is coupled to these coil pads 98 to provide electrical communication between the sensor 84 and the electrical wiring 88. One end of the sensor 84 may be coupled to one coil pad 98, and the other end of the sensor 84 may be coupled to the other coil pad 98. One coil pad 98 may be located on the upper surface of the substrate 86, and the other coil pad 98 may be located on the lower surface of the substrate 86.

[0034] The sensor assembly 82 further includes a proximal pad 100 positioned in the proximal region 90 of the substrate 86 and formed from a conductive material. Electrical wiring 88 is electrically coupled to the proximal pad 100, for example, by soldering or other preferred bonding means. The embodiment shown in Figure 7 shows four pairs of proximal pads 100, with each electrical wiring 88a, 88b coupled to each of the four pairs of proximal pads 100. Within the outer hub 58, the sensor cable 102 may be electrically coupled to the proximal pad 100, as best shown in the cross-sectional view of Figure 5. Here again, the electrical coupling may be by soldering or other preferred bonding means. The sensor cable 102 may include one, two, three, four, or more wires, each wire being electrically coupled to one of the four proximal pads 100. In one example, two wires of the sensor cable 102 are for transmitting sensor signals, and two other wires of the sensor cable 102 are for communicating calibration data, authentication data, and / or identification data from memory. The sensor cable 102 may be routed through a slot 104 (see Figure 1) of the handpiece 42 and may include a plug (not shown) configured to detachably connect to complementary hardware of the navigation system 154. Alternatively, an electrical connector 106 (see Figure 16) may electrically communicate with the sensor assembly 82 and may be configured to detachably connect to a complementary electrical connector 108 (see Figures 12 and 13) of the handpiece 42. In another variation, a wireless transceiver (not shown) may be electrically connected to the proximal pad 100 and configured to transmit data to a wireless receiver of the navigation system 154, thereby eliminating the need for the sensor cable 102. In certain embodiments, calibration data, authentication data, and / or identification data may be facilitated by a radiofrequency identification (RFID) tag 110 coupled to the cutting accessory 44. Figure 2 shows that the outer hub 58 may include a proximal housing 112 configured to be inserted into a cavity 60 of the handpiece 42. The proximal housing 112 may define a recess 114, and the RFID tag 116 may be fixedly supported within the recess 114.The RFID tag 116 may be positioned in an axial and / or radial position corresponding to an antenna (not identified) located on or inside the surface of the handpiece 42.

[0035] Returning to the coil sensor 84, it is desirable to maintain electrical insulation between the sensor 84 and the outer tube 66, which is typically formed from a conductive material. Therefore, in certain embodiments, the cutting attachment 44 may include an insulating spacer 116 bonded to the substrate 86 and coaxially positioned around the outer tube 66. In one exemplary embodiment, the insulating spacer 116 is a tubular compartment formed from a polymer such as polyimide. The insulating spacer 116 may have a dielectric constant of 3.3 to 3.5, or a dielectric constant of other preferred value based on the material properties of the tube assembly 64. During assembly, the coil sensor 84 is wound around the insulating spacer 116. The substrate 86, more specifically the distal region 94 of the substrate 86, is bonded to the insulating spacer 116. This bonding may be facilitated by an adhesive or other preferred bonding means. Figure 9A schematically represents the lamination, with the insulating spacer 116 coaxially positioned around the outer tube 66 and the coil sensor 84 coaxially positioned around the insulating spacer 116. Figure 9B shows another embodiment of the lamination, in which the substrate 86 includes a distal ring that forms a spindle on which a coil sensor 84 is coaxially positioned.

[0036] The cutting accessory 44 may include an insulating layer or sheath 118 coaxially positioned around the coil sensor 84, the substrate 86, and the electrical wiring 88. As can be seen from Figures 1-6, the sheath 118 may extend proximal to the top of the coil sensor 84, near or within the hub 58. The sheath 118 may overlap at least a portion of the outer tube 66, and may secure the coil sensor 84 and the electrical wiring 88 to the outer tube 66. The sheath 118 may be made of heat-shrinkable material, a polymer sheath secured to the outer tube 66, etc., and secures the position of the coil sensor 84 and the substrate 86 in an inconspicuous manner that does not interfere with the visualization of the cutting tip 72 when viewed along the tube assembly 64. The sheath 118 may extend from the outer hub 58, or may include a proximal end positioned distal to the outer hub 58 such that a portion of the tube assembly 64 is exposed. In one variation where the tube assembly 64 is straight and rigid, a rigid auxiliary tube (e.g., a hypo tube) may extend from the outer hub 58 and overlap and be coaxially positioned on the outer tube 66. The auxiliary tube may be joined to the outer tube 66 by, for example, spot welding, soldering, adhesive, or another suitable joining means.

[0037] Referring here to Figure 11, an exemplary method 200 for assembling the cutting accessory 44 is shown. An insulating tube is prepared (step 202). The insulating tube may be cut to a length to form an insulating spacer 116 sized to match the design length of the coil sensor 84 (step 204). The insulating spacer 116 may have a thickness of approximately 25 micrometers (μm). A conductive wire is wound around the insulating spacer 116 to form the coil sensor 84 (step 206). As previously mentioned, the wire may be wound in the range of approximately 300 to 2,200 turns, and more specifically, approximately 400 to 600 turns.

[0038] A flexible printed circuit board assembly (PCBA) is prepared (step 208), which includes electrical wiring 88 coupled to the board 86 in the twisted-pair and linear configurations described above. An insulating spacer 116 is fixed to the flexible PCBA by, for example, adhesive (step 210). In detail, the insulating spacer 116 may be glued to the distal region 94 of the board 86. A coil sensor 84, coaxially positioned around the insulating spacer 116, is soldered to the flexible PCBA (step 212) to establish electrical communication between the coil sensor 84 and the electrical wiring 88 on the board 86. For example, the ends of the coil sensor 84 may be coupled to a coil pad 98 by, for example, soldering. Any electrical tests may be performed to ensure that the electrical connections are satisfactory (step 214). The product may be considered a sensor flexible assembly provided for final assembly (step 216). Separately, a cutting accessory 44 is assembled (step 218) and provided for final assembly. The sensor flexible assembly is coupled to the cutting attachment (step 220). Specifically, the insulating spacer 116 and the coil sensor 84 are coaxially oriented so as to be positioned overlapping the outer tube 66 of the cutting attachment 44. Optionally, the outer tube 66 may include markings (e.g., laser etching or other marks) to facilitate the intuitive and reproducible positioning of the sensor flexible assembly at a desired location on the outer tube 66.

[0039] In certain modifications, the flexible region 92 of the substrate 86 is axially positioned with respect to the bend 76 or flexible region 78 of the outer tube 66. The substrate 86 is fixed to the outer tube, which may include thermally shrinking the sheath 118 coaxially around the substrate 86 and the coil sensor 84. The method may also include soldering the wires of the sensor cable 102 to the proximal pad 100 to establish electrical communication between the sensor cable 102 and the coil sensor 84.

[0040] Referring here to Figures 12 to 14B, another embodiment of the cutting accessory 44 is provided, in which the tube assembly 64 is configured to be bent and / or straightened by the user into a shaped form. More specifically, at least a portion of the tube assembly 64 may include a flexible region 78 so that the user can bend it into a shaped form, and after bending, the tube assembly 64 is robust enough to maintain the shaped form despite the axial and radial forces associated with deploying the cutting tip 72 to the surgical site. The shaped form may range from a 1-degree bend to 30, 60, 90 degrees, and even greater bends. As best shown in Figures 12 and 13, the outer tube 66 includes at least one slotted region in which a series of slots 120 form at least one flexible spine portion 122. The flexible spine portion 122 is configured to be bent and / or straightened by the user into a shaped form to maintain the tube assembly 64 in the shaped form. The cutting accessory 44 allows the sensor 84 to be coupled to the assembly 64 at a distal position relative to the flexible region 78. As a result, regardless of the nature and amount of bending applied to the tube assembly 64, the data indicating the location of the cutting chip 72 transmitted from the sensor 84 to the navigation software remains sufficiently accurate, and furthermore, does not require recalibration after successive bending events.

[0041] The electrical wiring 88 extends proximally from the sensor 82 to the electronic subcomponents within the outer hub 58. The wiring 88 may extend along the flexible spine 122 to limit the strain associated with bending the tube assembly 64. Additionally, or alternatively, at least a portion of the electrical wiring 88 may be arranged in a serpentine configuration (not shown) to further limit the strain associated with bending. The electrical wiring 88 may be in stranded pairs to reduce interference from the sensor 84. As can be seen together from Figures 12 to 14A, a second sensor 84 may be coupled to the opposite side of the outer tube 66, with the second electrical wiring 88 extending along the opposite flexible spine 122. The sensor 84 may be a 5DOF sensor oriented at a predetermined angle between the direction vectors of each sensor 84. The predetermined angle provides information for controlling rotational position tracking. In another modification, the sensor 84 may be positioned below the cutting tip 72 on the opposite side of the cutting window 74 to avoid obstructing the view of the cutting tip 72. Alternatively, Figure 14B shows sensor 84 as a coil sensor. Therefore, it should be recognized that the sensor assembly 82 described earlier may be mounted on a tube assembly 64 having a flexible region 78.

[0042] Referring to Figures 16 to 21, the sensor assembly 82 may include an electrical bridge 124 and an electrical connector 106. As used herein, the term “bridge” is intended to mean a subcomponent that provides electrical communication between the sensor 84 and the electrical connector 106 on the proximal side of the outer hub 58. Unless otherwise specified, the term is not intended to mean a bridge circuit. The electrical bridge 124 is located inside the housing 126 of the hub 58. The electrical bridge 124 includes a board 128 and a ribbon 130 coupled to and extending from the board 128. The electrical connector 106 is coupled to the ribbon 130. The internal shape of the housing 126 is formed to provide a desired path for the board 128 and ribbon 130 to extend without interfering with other subcomponents of the cutting accessories 44 which will be described later.

[0043] Figures 17 and 18 show a first embodiment of the electrical bridge 124, in which electrical communication is established between electrical wiring 88 and an electrical connector 106. Wiring 88 extends proximal to the housing 126 along the tube assembly 64, and the proximal end of wiring 88 is coupled to the board 128 of the electrical bridge 124 using, for example, a pad 132 or other suitable fastening means. At least two electrical wires 134 extend through the ribbon 130. The electrical connector 106 may be a male pin connector, with pins arranged to communicate electrically with the wiring 134. Alternatively, the electrical connector 106 may be a female pin connector, with a male pin connector located on the handpiece 42 (see Figures 12 and 13). The 6-pin connector may use four pins for EM signals (two for each 5DOF difference signal) and two pins for communication of calibration data, authentication data, and / or identification data from memory 136 (single-wire serial communication). The wiring 134 may be tightly coupled and routed as a differential pair. In one example, the wiring 134 has a width of less than 0.20 millimeters, and the space between the tightly coupled wirings is less than 0.25 millimeters, thereby reducing susceptibility to external noise.

[0044] The electrical bridge 124 forms a flexible circuit configured to accommodate the rotation of the outer tube 66, i.e., an embodiment of the cutting attachment 44 that allows the orientation of the bend to be changed. The board 128 is fixedly coupled to the outer tube 66, and the ribbon 130 may be formed from a flexible material. The board 128 may define a cutout 138 or opening through which the tube assembly 64 passes and extends. The inner diameter of the cutout 138 may be approximately the outer diameter of the outer tube 66. The ribbon 130 may be arranged in a meandering configuration having at least one folding feature 140, which is configured to be folded, unfolded, or otherwise provide slack. The folding feature 140 may be formed by folding a flat portion of the ribbon 130 in half and overlapping it on top of itself. Figures 17 and 18 show a first folding feature 140a positioned adjacent to the proximal side of the board 128. The meandering configuration may include a U-shaped section 142 as shown in the figure, and a second folding feature section 140b may be located within a straightened section 144 extending in the direction from proximal to distal. The proximal section 146 may extend upward in an arc shape with a contour that matches the inner surface of the housing 126. The proximal section 146 is coupled to an electrical connector 106.

[0045] As the outer tube 66 rotates within the housing 126, the board 128 rotates in correspondence. Due to the properties and arrangement of the flexible material forming the ribbon 130 and the first folding feature portion 140a (and U-shaped portion 142), the slack provided by the ribbon 130 allows the board 128 to rotate in both counterclockwise and clockwise directions within a predetermined maximum angle related to the bending angle adjustment capability of the cutting accessory 44. The predetermined maximum angle may be at least 90 degrees.

[0046] The sensor assembly 82 may include a memory 136 for storing calibration data indicating the location of the sensor 84 relative to a reference feature of the cutting tip 72, such as an edge, boundary, or tracking point as described later. In one example, the sensor 84 is positioned proximal to the cutting window 74 or distal to the cutting window 74, as shown in Figures 13, 14A, and 14B. In embodiments where the tube assembly 64 has a flexible region 78, the sensor 84 is positioned distal to the flexible region 78. A sensor 84 positioned near the cutting tip 72 may also be implemented in cutting accessories where the tube assembly 64 is rigid. The sensor 84 may be located at a determinable distance along one, two, or three axes relative to the reference feature of the cutting tip 72. In other words, the tracking points as described later may be offset from the sensor 84 along the x, y, and / or z axes. When the cutting accessory 44 is assembled, the distance is determined, calibrated, and / or verified and stored in the memory 136. Therefore, after the initial setup of the navigation system 154, the cutting accessories 44 may be "plug and play" with minimal further input or configuration required by the user.

[0047] Figure 19 shows another embodiment of the sensor assembly 82, in which two sensors 84 are coupled to a board 128 of an electrical bridge 124. The sensors 84 in the embodiment shown are two 5DOF sensors oriented at an angle to each other. Since the sensors 84 are located inside the housing 126, it may not be necessary to place the wiring 88 and sensors 84 near the cutting tip 72. Such an alternative method is particularly well suited to embodiments in which the tube assembly 64 is rigid (has no bends or has fixed (constant) bends). The sensors 84 located on the board 128 may be provided in addition to one or more sensors 84 located near the cutting tip 72. As can be seen from Figure 19, the coupling of the sensors 84 to the board 128 fixes the position of the sensors 84 relative to the cutting tip 72, thus eliminating the need for the folded feature 140 of the ribbon 130. The board 128 may or may not be fixed to the outer tube 66.

[0048] The electrical connector 106 of the cutting accessory 44 is configured to be detachably coupled to a complementary electrical connector 108 of the handpiece 42 (see Figures 12 and 13). Furthermore, the electrical connector 106 eliminates the need for a separate data cable extending from the handpiece 42. The outer hub 58 may include a proximal-facing surface 152. The electrical connector 106 is located within or extends from the surface 152 and is positioned distal to the coupling structure of the drive hub 62 and the outer hub 58. The axial spacing of the electrical connector 106 relative to the drive hub 62 and the coupling structure is such that an electrical connection occurs between the electrical connectors 106 and 108 when a mechanical connection is formed between the cutting accessory 44 and the handpiece 42. During pre-treatment or in-treatment setup, the user may simply couple the cutting accessory 44 to the handpiece 42, and many of the remaining steps may then occur automatically. For example, memory 136 (or other electronic module) may transmit data to the processor 156 of the navigation system 154 (see Figure 23) so that the processor 156 can verify the authenticity of the cutting accessory 44. The data may be transmitted by an RFID tag 110, or alternatively, in the form of a programmed, erasable, programmable, read-only memory (EPROM).

[0049] If the cutting accessory 44 is not genuine, a prompt may be displayed on the navigation system 154's display 160, and / or the processor 156 may prevent the power supply 52 from operating the surgical cutting instrument 40. If the authenticity of the cutting accessory 44 is confirmed, calibration data may be sent from memory 136 to the processor 156. The calibration data includes the position of the tracking point relative to the sensor 84, i.e., an offset in 1, 2, or 3 dimensions. The calibration data may also include other data, such as identification data indicating the type of cutting accessory 44, which may be used to provide the display 160 with type-specific options and operating parameters.

[0050] Referring to Figures 20-22, another embodiment of the hub 58 is shown, in which the sensor assembly 82 includes a sensor 84 coupled to the board 128. Unlike the previous embodiment, the cutting attachment 44 may not include the electrical bridge 124 or the electrical connector 106 on the hub 58. Instead, the sensor cable 102 may be coupled to the board 128 and extend through an opening 148 defined by the housing 126. At the opposite end, the sensor cable 102 may include a plug (not shown) configured to be detachably coupled to complementary hardware of the navigation system 154. A flange 150 may extend from the underside of the board 128 to support the joint between the sensor cable 102 and the board 128. One or more tube management clips (not shown) may also be provided.

[0051] Figure 29 shows the housing 126 of the cutting accessory 44, which includes a body 166 and a neck portion 168 extending from the body 166. Since the bur embodiment does not require gears or other mechanisms to allow rotation of the window, the neck portion 168 may be relatively thinner than the body 166 and may be sized to accommodate a surgeon's finger to improve grip during high-speed burring. Another embodiment of the sensor assembly 82, with a thinner neck portion 168, is shown in Figures 32 and 33. Figure 32 shows housing portions 170 and 172, which are disassembled to show that the sensor assembly 82 is coupled to a collar 174 fixed to the outer tube 66. In detail, the collar 174 includes a proximal flange defining a slot 176 or other rotation-preventing mechanism. The board 128 of the sensor assembly 82 includes a projection 178 or another complementary feature configured to engage with the slot 176. This engagement prevents the board 128 from rotating relative to the collar 174, which is rotatably fixed to the outer tube 66. The drive shaft 68 is configured to rotate within the outer tube 66 and is therefore further configured to rotate relative to the collar 174. Thus, the sensor assembly 82 remains in a fixed position relative to the cutting tip 72. Among its various advantages, the sensor assembly 82 of this embodiment is particularly small in size to accommodate in the neck portion 168 of the housing 126.

[0052] Board 128 is designed to be flexible to wrap around components and may be aligned with a central longitudinal axis. Board 128 may include a central portion 180 and wing portions 182 (one shown) extending from the central portion 180. Projections 178 may be located on the central portion 180. The wing portions 182 may extend in an arc shape around the sides of the collar 174 or outer tube 66 and are generally formed to match the sides of the collar 174 or outer tube 66. Each sensor 84 (one shown) may be located on each of the wing portions 182. Sensor cables (not shown) may be coupled to board 128 and extend through openings defined by the housing 126. Sensor cables may include plugs (not shown) configured to be detachably coupled to complementary hardware of the navigation system 154.

[0053] An embodiment of the cutting accessory 44 is used in conjunction with the navigation system 154, particularly in an intuitive plug-and-play manner. Referring here to Figure 23, the navigation system 154 includes a processor 156, at least one electric field generator 158, and a display 160. The processor 156 is operable to drive the electric field generator 158 to generate EM fields of different frequencies around the head of the patient (P). The sensor 84 generates an electrical signal based on the changed EM field. The electrical signal is transmitted from the sensor assembly 82 to the processor 156, through electrical connectors 106, 108, where applicable. The processor 156 is configured to determine the position of the sensor 84 in three-dimensional space by determining position data based on the electrical signal received from the sensor assembly 82. Furthermore, based on calibration data, the processor 156 determines the position of a reference feature (e.g., a tracking point) in three-dimensional equipment space.

[0054] Preoperative or intraoperative images of the patient's anatomical structures, such as computed tomography or magnetic resonance imaging scans, may be received by the processor 156. The scans may be aligned to a three-dimensional instrument space through means known in the art. For example, the position of the electric field generator 158 may be fixed and determined within the three-dimensional instrument space. As a result, the navigation system 154 is configured to display a representation of the cutting instrument 40 on the patient's anatomical structures in real time on the display 160. Figure 24 shows a typical output of the display 160, where multiple images of the patient's anatomical structures are shown (e.g., external, coronal, sagittal, etc.). One or more of these images may be marked to help the surgeon understand the location of the cutting tip 72, more specifically the tracking point, on the patient's anatomical structures. The markings may include crosshairs, axes, etc.

[0055] In conventional microdebriders / shavers, the rounded shape of the cutting tip can lead to a distorted perception of the instrument's appearance on the display. Referring to Figures 26–31, the cutting tip 72 of the cutting accessory 44 overcomes such drawbacks by providing a tip geometry 162 with a tracking point 164 that is more accurately traceable and intuitively understandable to the surgeon viewing the tracking point 164' displayed on the display 160. For example, the symbol may include a circle representing the cutting window 74. In addition to the displayed tracking point 164', additional visual markers may be provided based on other aspects of the cutting tip 72. Thus, in certain embodiments, the navigation system 154 is configured to allow the surgeon to select a point or feature on the cutting tip visualized on the display 160, possibly in addition to the tracking point. As shown in Figure 25, the user may choose to visualize one or more of the following features, but are not limited to: the central axis of the tube assembly 64 (top), the midpoint of the cutting window 74 (top center), the opening of the cutting window 74 (bottom center), and the distal end of the cutting tip 72 (bottom).

[0056] As described above, calibration data for navigation and tracking is associated with clearly defined points or features on the cutting tip that are fixed to the feature area being cut, such as the center of the cutting window or the hood extension adjacent to the bar head. Such associations improve the accuracy and precision of calibration and tracking. By making the tracking points understandable to the surgeon, uncertainty regarding the location of the cutting window or bar head can be eliminated. Known systems require the surgeon to use two devices: a dedicated pointer device and a cutting device. However, in this embodiment, the cutting tip may also be used as a “pointer” during a procedure, e.g., an ENT procedure, so that the surgeon can understand the orientation (i.e., position and orientation) of the cutting tip as displayed in the navigation software. Since the defined features are fixed or stationary on the cutting tip, additional markings (e.g., graphic symbols) may be used on the display to provide additional information about the cutting tip (e.g., location of the distal tip, center of the cutting window, edge of the cutting window, longitudinal axis, and / or similar). The markings may be drawn to more accurately mimic the cutting tip, which may be specific to one of several selectable cutting accessories. In embodiments where the cutting accessory 44 is a shaver / microdeblider, the drive shaft 68 defines the suction lumen, and the feature is the distal or center point of the cutting window 74. In embodiments where the cutting tip 72 is a bar head, the feature may be the distal or center point of the bar head. The sensor 84 (e.g., a coil sensor) is positioned proximal to the feature by a calibrated distance.

[0057] The tip shape 162 may extend directly from the end of the cutting tip 72 through its central axis, or it may extend along alternating vectors. The tip shape 162 may form a distal pointed tip or shape, or a spherical shape (e.g., a small sphere attached to the distal end of the cutting tip 72), as shown. The pointed shape may extend considerably beyond the cutting window 74, for example, 0.5, 1.0, or 2.0 centimeters, or more. Variations of the shape are possible. The pointed tips described above may be manufactured by metal injection molding, machining, stretching, or other preferred manufacturing methods. In one variation, the tip shape 162 may take the form of an extruded / embossed surface or feature near the distal tip to communicate the tracking point 164 to the user. Additionally, or alternatively, the tracking point 164 may be indicated by the navigation system 154 using a decal with laser marking or etching.

[0058] Aspects of the present disclosure are configured for use in a cutting accessory 44 which is a bur. The bur may be a diamond bur, a grooved bur, or a bur head of any other suitable type and size. Aspects of the present disclosure may also be used in other cutting instruments such as scrapers, files, cutting edges, trephines, brushes, or in non-cutting manual or powered instruments such as screwdrivers, endoscope cameras, lighting assemblies, and suction devices. Referring to Figures 18–22, the cutting tip 72 of the cutting accessory 44 includes a bur head, and the tip shape 162 includes a hood extension from an outer tube 66. The hood extension may extend laterally adjacent to the bur head, and in detail may extend above and beyond the bur head as shown. The tracking point 164 of the tip shape 162 may be the pointed tip of the hood extension. Similar to the pointed shape of a microdebrider / shaver, the pointed tip of the hood extension provides the surgeon with a distinctive feature of the cutting tip 72 at the location being tracked. Therefore, when visualizing the markings displayed on the display 160, the surgeon can easily recognize the orientation of the bar head relative to adjacent anatomical structures. Furthermore, since the tracking point 164 is an extension of the outer tube 66 (fixed or flexible), relative movement of the cutting tip does not affect the tracking point. As a result, the cutting accessory 44, including the bar head, can be implemented in a tube assembly 64 that is fixed, articulated, or flexible. In addition, a hood extension is configured to protect tissue from the opposite side of the bar head. In one modification, an intermediate tube 70 may define the tubular distal end from which the bar head extends, and the hood extension may be coupled to the intermediate tube 70. Thus, the hood extension may be movably coupled to an actuator so that the surgeon can rotate the hood extension around its longitudinal axis as needed.

[0059] In any of the embodiments described above, the cutting accessory 44 allows for the selective rotation of the cutting window 74 in an intuitive and ergonomic manner. Referring to Figures 13, 15, 16, and 21, the housing 126 may be formed from housing portions 170, 172 joined together. The housing portions 170, 172 have several internal shapes defining a gap and are configured to house and support the internal subcomponents of the cutting accessory 44. The housing 126 may include a base 184 and a neck portion 186 formed by a contour surface extending upward from the base 184. The contour surface may function as a support point for the cutting accessory 44, held between the surgeon's index or middle finger and thumb. The neck portion 186 terminates with a crown portion 188 defining a substantially circular edge or opening. The crown portion 188 may be inclined with respect to the longitudinal axis (LA) of the tube assembly 64, as best shown in Figures 4 and 9.

[0060] The actuator 190 is operably coupled to the housing 126. In an exemplary illustrated embodiment, the actuator 190 is a dial or wheel positioned on top of the crown portion 188 of the housing 126. The upper edge of the dial may be rounded or otherwise curved. The dial may include a lower edge that approximates the shape of the crown portion 188 such that the contours of the neck portion 186 and the crown portion 188 are substantially continuous with the contour of the dial. As a result, the surgeon can comfortably move the position of their finger between the dial and the contour surface of the housing 126. The dial may include ridges, textures, or other gripping mechanisms configured to provide the surgeon with tactile feedback when changing finger position. Additionally or alternatively, the dial may be formed slightly larger than the crown portion 188 to provide the surgeon with a distinct tactile sensation when changing finger position. The dial may be coaxially aligned with the dial axis (AD). The dial axis may be perpendicular to the inclination of the crown portion 188. The angle α defined between the dial axis and the longitudinal axis may be an acute angle less than (and not equal to) 90 degrees. Because the lower edge of the dial is positioned adjacent to the crown portion 188, the dial faces distally upward. This orientation has been shown to be ergonomically superior to known devices in which larger disc-shaped dials face horizontally and require support on the upper side of the disc-shaped dial. This embodiment allows the dial to be supported from below within the housing 126, thereby reducing visual obstruction during the use of the surgical cutting instrument 40 and providing a flat upper resting surface for the surgeon's index finger to facilitate repeated and / or fine dial operations.

[0061] The actuator 190 includes a flange 192 rotatably housed within the cavity of the housing 126. As can be seen from Figures 15 and 21, this arrangement fixes the dial to the housing 126 in five degrees of freedom, but otherwise allows rotation of the dial about the dial axis. The dial further includes a lower bevel gear 194. The actuator 190 of the cutting attachment 44 includes an inner hub 196 with a complementary bevel gear 197 configured to engage with the lower bevel gear 194 of the dial. The angled bevel gears may have gear ratios in the range of approximately 0.5:1 to 3:1, more specifically in the range of approximately 1:1 to 2:1. The inner hub 196 is rotatably supported by its internal shape within the housing 126 and is fixedly coupled to the intermediate tube 70. Thus, input from the surgeon to rotate the dial gives rotation of the intermediate tube 70 about its longitudinal axis. The cutting window 74, defined by the intermediate tube 70, rotates in response to input to the dial.

[0062] The function of rotating the cutting window 74 around the longitudinal axis may be provided in a tube assembly 64 that is rigid and straight, rigid and angled, articulated, or bendable. In one of the later modifications in which the tube assembly is angled, articulated, or bendable, the actuator 190 (or a second bending actuator) may be operably coupled to the outer tube 66. The actuator is configured to receive another input from the surgeon to change the orientation of the bend (i.e., rotate the distal portion of the tube assembly 64 around the longitudinal axis). Figures 15 and 16 show a second internal hub 198 rotatably supported by the internal geometry within the housing 126. The second internal hub 198 is fixedly coupled to the outer tube 66. A collar 174 is operably coupled to the second internal hub 198 and supported within the housing 126. The second internal hub 198 and / or collar 174 are configured to be coupled to a bending actuator (not shown) through an opening (not shown) in the housing 126. Another exemplary configuration for selectively directing a bend is disclosed in International Publication WO2022 / 224218, published on 27 October 2022, owned by the applicant, and the entire contents of that document are incorporated by reference.

[0063] Alternative embodiments of the actuator 190 for rotating the cutting window 74 are shown in Figures 34A to 34D. Figure 34A shows a pivotable lever located in a recess of the housing 126. Figure 34B shows a slider located movably in a recess of the housing 126. The lever or slider may be spring-driven to return from the operating position to its original position when there is no input, or it may be selectively positionable between the original position and the operating position. Figure 34C shows a barrel located rotatably in a recess of the housing 126. The axis on which the barrel is configured to rotate it may be oriented perpendicular to the longitudinal axis of the tube assembly 64. The barrel may be operably coupled to an intermediate tube (not shown) in a worm gear configuration. Figure 34D shows a wheel configured to rotate about an axis coaxial with the longitudinal axis of the tube assembly 64. Further details of embodiments including the wheel are disclosed in U.S. Patent Publication 2020 / 0146702, published on 14 May 2020, owned by the present patent holder, and the entire contents of that document are incorporated by reference. Embodiments of the actuator 190 include a suitable gear system or other mechanism for performing rotation of the cutting window 74 while maintaining sufficient clearance for the tube assembly 64 and other subcomponents located within the housing 126. The cutting attachment 44 may also include a release input 191 operably coupled to a latch mechanism (not shown) for detaching the cutting attachment 44 from the handpiece 42. The release input 191 may be a button release, a sliding release, a push release, a pull release, or other means.

[0064] The above disclosure is not intended to be exhaustive or to limit the invention to any particular form. The terms used are intended to be descriptive rather than restrictive. Many modifications and variations are possible in light of the above teachings, and the invention may be carried out in ways other than those specifically described.

[0065] Further embodiments of the invention of this disclosure are shown in the following exemplary clauses.

[0066] Item 1: A cutting accessory configured to be detachably coupled to a handpiece of a surgical cutting instrument including a motor and an electrical outlet, comprising: an outer hub configured to be operably coupled to the handpiece; a drive hub rotatably disposed within the outer hub and configured to be operably coupled to a motor; a tube assembly comprising an outer tube extending distally from the outer hub, an inner tube coupled to the drive hub and coaxially disposed within the outer tube, and a cutting tip; a sensor assembly comprising at least one navigation sensor, an electrical bridge disposed within the outer hub and coupled to at least one navigation sensor, and an electrical connector coupled to the outer hub and the electrical bridge; the cutting accessory comprising an electrical connector configured to be coupled to an electrical outlet of the handpiece with the drive hub operably coupled to the motor.

[0067] Item 2: The cutting attachment of Item 1, wherein the outer hub has a proximal-facing surface, and the electrical connector is located on the proximal-facing surface and distal to the drive hub.

[0068] Item 3: A cutting accessory according to Item 1 or 2, wherein the electrical connector comprises six pins, four of which are configured to transmit navigation data and two of which are configured to transmit authentication data.

[0069] Item 4: A cutting accessory according to Item 1 or 2, comprising an electrical bridge, a ribbon extending between the board and an electrical connector and connecting them, and memory coupled to the board.

[0070] Item 5 A cutting accessory configured to be detachably coupled to a handpiece of a surgical cutting instrument including a motor and an electrical outlet, comprising: an outer hub configured to be operably coupled to the handpiece and defining an opening; a drive hub rotatably disposed within the outer hub and configured to be operably coupled to a motor; a tube assembly comprising an outer tube extending distally from the outer hub, an inner tube coupled to the drive hub and coaxially disposed within the outer tube, and a cutting tip; a sensor assembly comprising a board, at least one navigation sensor coupled to the board, and a sensor cable coupled to the board and electrically communicating with at least one navigation sensor; the cutting accessory comprising a sensor cable extending through an opening in the outer hub and configured to be coupled to complementary hardware of a navigation system.

[0071] Item 6: The cutting accessory of Item 5, wherein the sensor assembly further comprises a flange extending from the board and supporting the joint between the sensor cable and the board.

[0072] Item 7 A cutting accessory from any one of Items 4 to 6, wherein the cutting chip has a chip shape and the memory stores calibration data indicating the position of a tracking point of the chip shape for at least one navigation sensor.

[0073] Item 8: A cutting accessory of item 7, wherein the tip shape is either pointed or spherical.

[0074] Item 9 A cutting attachment from any one of Items 4-8, wherein the board defines a cutout or opening, and the outer tube and inner tube extend through the cutout or opening.

[0075] Item 10: The cutting accessory of Item 4, wherein the ribbon is arranged in a meandering configuration through a gap defined by the internal shape within the outer hub.

[0076] The cutting accessory of item 10, wherein the ribbon comprises at least two electrical wires tightly coupled and wired as a differential pair, wherein the wires have a width of less than 0.20 mm and the space between the wires is less than 0.25 mm.

[0077] Item 12 A cutting accessory from any one of Items 1 to 11, wherein at least one navigation sensor is coupled to an outer tube adjacent to a cutting tip, and the cutting accessory further comprises at least one electrical wire extending along the outer tube and coupling at least one navigation sensor to a board, and optionally at least one electrical wire is a twisted pair.

[0078] Item 13: The cutting accessory of Item 12, further comprising a sheath bonded to the outer surface of the outer tube and overlapping at least one wiring and at least one navigation sensor.

[0079] The cutting accessory of item 12, wherein the tube assembly further comprises an auxiliary tube extending from the outer hub along the outer surface of the outer tube, and at least one wiring extending through the auxiliary tube.

[0080] Item 15: A cutting attachment from any one of Items 1 to 14, wherein the outer tube comprises a flexible region and at least one navigation sensor is positioned distal to the flexible region.

[0081] Item 16 Cutting accessory configured to be detachably coupled to a handpiece of a surgical cutting instrument including a motor and an electrical outlet, comprising: an outer hub configured to be operably coupled to the handpiece; a drive hub rotatably disposed within the outer hub and configured to be operably coupled to a motor; a tube assembly comprising an outer tube extending distally from the outer hub, an inner tube coupled to the drive hub and coaxially disposed within the outer tube, and a cutting tip on the inner tube, wherein the outer tube comprises a flexible region and the inner tube comprises a flexible region disposed within the flexible region; a sensor assembly comprising at least one navigation sensor coupled to the outer tube distal to the flexible region, and at least one wiring coupled to the at least one navigation sensor; and a cutting accessory comprising at least one wiring extending along the outer tube into the outer hub.

[0082] Item 17 The flexible region comprises a series of slots forming a flexible spine configured to be bent and / or straightened by the user into a shaped form and to maintain the tube assembly in a shaped form, and at least one wiring extending along the flexible spine, the cutting accessory of Item 16.

[0083] Item 18 A cutting accessory of item 16 or 17, further comprising a sheath bonded to the outer surface of the outer tube and overlapping at least one wiring and at least one navigation sensor.

[0084] Item 19 A cutting attachment of any one of items 16-18, wherein at least a portion of at least one wiring is arranged in a meandering configuration.

[0085] Item 20: A cutting accessory from any one of items 16-19, further comprising an electrical bridge located within an outer hub, with at least one wire coupled to the electrical bridge.

[0086] Item 21 A cutting accessory of any one of items 16-20, wherein the sensor assembly further comprises a memory for storing calibration data indicating the location of at least one navigation sensor relative to a tracking point of the cutting chip.

[0087] Item 22 Cutting accessory configured to be detachably coupled to a handpiece of a surgical cutting instrument including a motor and an electrical outlet, comprising: an outer hub configured to be operably coupled to the handpiece; a drive hub rotatably disposed within the outer hub and configured to be operably coupled to a motor; a tube assembly comprising an outer tube extending distally from the outer hub, an inner tube coupled to the drive hub and coaxially disposed within the outer tube; and a cutting tip; a sensor assembly comprising at least one navigation sensor, an electrical bridge having a board to which at least one navigation sensor is coupled, a ribbon extending from the board and having wiring for electronically communicating with at least one navigation sensor, and a memory coupled to the board and storing calibration data indicating the location of at least one navigation sensor relative to a tracking point of the cutting tip; a cutting accessory comprising;

[0088] Item 23: A cutting attachment according to Item 22, wherein the board defines a cutout or opening, and an outer tube and an inner tube extend through the cutout or opening.

[0089] Item 24 The wiring is tightly coupled and wired as a differential pair, and optionally the wiring has a width of less than 0.20 mm and the space between the wirings is less than 0.25 mm, for the cutting accessories of Item 22 or 23.

[0090] Item 25: A cutting accessory from any one of Items 22-24, wherein the cutting tip has a tip shape with a tracking point, and optionally the tip shape is either pointed or spherical.

[0091] Item 26: A memory that further stores identification data and / or authentication data indicating the characteristics of the type of cutting accessory, for any one of the cutting accessories specified in items 22-25.

[0092] Section 27 Cutting accessory configured to be detachably coupled to a handpiece of a surgical cutting instrument including a motor and an electrical outlet, comprising: an outer hub configured to be coupled to the handpiece; a drive hub rotatably disposed within the outer hub and configured to be operably coupled to the motor; a tube assembly comprising an outer tube extending distally from the outer hub, an intermediate tube coaxially disposed within the outer tube, an inner tube coupled to the drive hub and coaxially disposed within the intermediate tube, and a cutting tip, and comprising a bend; a bend actuator operably coupled to the outer tube, configured to receive user input to rotate the outer tube relative to the outer hub, thereby selectively rotating the bend of the tube assembly about its longitudinal axis; a sensor assembly comprising at least one navigation sensor coupled to the cutting tip at an axial position distal to the bend, a board disposed within the outer hub, an electronics bridge coupled to the outer tube, and a ribbon extending from the board; and a cutting accessory comprising the ribbon being configured to provide slack that allows the board to rotate within the outer hub as the outer tube rotates in response to the bend actuator receiving user input from the user.

[0093] Item 28: The cutting accessory of Item 27, wherein the ribbon is arranged in a meandering configuration through a gap defined by the internal shape within the outer hub.

[0094] Item 29 A serpentine configuration of the cutting accessory of Item 28, wherein the ribbon has at least one folded feature portion that overlaps itself, and the at least one folded feature portion is configured to fold or unfold in response to the rotation of the board.

[0095] Item 30: A cutting accessory according to item 28 or 29, wherein the meandering configuration comprises at least one U-shaped section.

[0096] Item 31 A cutting accessory of any one of Items 27-30, wherein the ribbon comprises at least two wires tightly coupled and wired as a differential pair, and optionally, the at least two wires have a width of 0.20 mm, and the space between the at least two wires is less than 0.25 mm.

[0097] Item 32 Cutting accessory configured to be detachably coupled to a handpiece of a surgical cutting instrument including a motor and an electrical outlet, comprising: an outer hub configured to be operably coupled to the handpiece; a drive hub rotatably disposed within the outer hub and configured to be operably coupled to a motor; a tube assembly comprising an outer tube extending distally from the outer hub, an inner tube coupled to the drive hub and coaxially disposed within the outer tube, and a cutting tip disposed within the inner tube, the cutting tip having a distal pointed tip; a sensor assembly comprising at least one navigation sensor and a sensor assembly for storing calibration data indicating the location of the distal pointed tip relative to at least one navigation sensor;

[0098] Item 33: A cutting accessory of item 32, wherein the outer tube defines a cutting window, and the distal pointed tip is integrally formed with the outer tube distal to the cutting window.

[0099] Item 34: A cutting accessory of item 32 or 33, wherein the distal pointed tip is coaxial with the central longitudinal axis of the distal compartment of the tube assembly.

[0100] Item 35: A cutting attachment of item 32 or 33, wherein the distal pointed tip is positioned on an angled vector with respect to the central longitudinal axis of the distal compartment of the tube assembly.

[0101] Item 36 A cutting accessory of any one of items 32-35, wherein the distal pointed tip has a marking or etching portion that indicates a point to be displayed on the navigation system's display.

[0102] Item 37: The cutting accessory of item 36, wherein the cutting tip is a bar head, and the outer tube comprises a hood extension extending laterally distal to the bar head, the hood extension having a pointed tip distal to the bar head.

[0103] Item 38: A cutting accessory from any one of items 1 to 37, wherein at least one navigation sensor is two 5-degree-of-freedom sensors positioned at a predetermined angle to each other.

[0104] Item 39: At least one navigation sensor is a 6-degree-of-freedom sensor, and one cutting accessory is one of items 1 through 37.

[0105] Item 40 Equipment for use with a navigation system, the equipment accessories comprising: a hub; an outer tube extending from the hub; a chip positioned at the distal end of the outer tube; and a sensor assembly configured to be electronically communicative with the navigation system, wherein the sensor assembly comprises: a substrate coupled to the outer tube and extending along the outer tube, having a flexible region and a proximal region between the flexible region and the hub; electrical wiring extending along the substrate, arranged in a twisted-pair configuration in the proximal region and in a linear configuration in the flexible region; and a coil sensor coaxially positioned around the outer tube between the flexible region and the chip, the coil sensor communicating electrically with the electrical wiring, and the coil sensor configured to detect changes in the electric field induced by the navigation system.

[0106] Item 41 Equipment for use with a navigation system, the equipment accessories comprising: a hub; an outer tube extending from the hub; a tip located at the distal end of the outer tube; a sensor assembly configured to be electronically communicative with the navigation system; the sensor assembly comprising: a substrate coupled to the outer tube and extending along the outer tube; electrical wiring extending along the substrate; a coil sensor including conductive wires coaxially wound around the outer tube and spaced proximal to the tip by a calibrated distance, configured to electrically communicate with the electrical wiring and to detect changes in the electric field induced by the navigation system; and a sheath coaxially positioned around the substrate and the coil sensor.

[0107] Item 42 Equipment for use with a navigation system, the equipment accessories comprising: a hub; an outer tube extending from the hub; a tip positioned at the distal end of the outer tube; a drive shaft coaxially and rotatably positioned within the outer tube; and a sensor assembly configured to be electronically communicative with the navigation system; wherein the sensor assembly comprises: a substrate coupled to the outer tube and extending along the outer tube; electrical wiring extending along the substrate; an insulating spacer coupled to the substrate and coaxially positioned around the outer tube; and a coil sensor coaxially positioned around the insulating spacer, configured to electrically communicate with the electrical wiring and to detect changes in an electric field induced by the navigation system.

[0108] Item 43 Equipment for use with a navigation system, the equipment accessories comprising: a hub; an outer tube extending from the hub and having a bend or flexible region; a tip positioned at the distal end of the outer tube; and a sensor assembly configured to be electronically communicative with the navigation system, wherein the sensor assembly comprises: a substrate coupled to the outer tube and extending along the outer tube, the substrate having a proximal region and a flexible region, the width of the flexible region being less than the width of the proximal region, and at least a portion of the flexible region of the substrate being aligned with the bend or flexible region of the outer tube; electrical wiring extending along the substrate; and a coil sensor coaxially positioned around the outer tube between the flexible region and the cutting tip, the coil sensor being configured to electrically communicate with the electrical wiring and to detect changes in the electric field induced by the navigation system.

[0109] Item 44 Equipment for use with a navigation system, the equipment accessories comprising: a hub; an outer tube extending from the hub; a tip positioned at the distal end of the outer tube; and a sensor assembly configured to be electronically communicative with the navigation system, the sensor assembly comprising a coil sensor coaxially positioned around the outer tube, the coil sensor being formed from gauge wire and number of turns to provide sensor sensitivity that compensates for the material properties of the outer tube.

[0110] Item 45: Any one of the devices in items 40-44, wherein the device is one of the following: a scraper, a file, a blade, a trephine, a brush, a screwdriver, an endoscope camera, a lighting assembly, and a suction device.

Claims

1. Cutting accessories for powered surgical instruments used with a navigation system, A hub configured to be detachably coupled to the handpiece of the powered surgical instrument, An outer tube extending from the hub, A drive shaft is coaxially and rotatably arranged inside the outer tube, A cutting tip positioned at the distal end of the drive shaft, A sensor assembly configured to be electronically communicative with the aforementioned navigation system and The sensor assembly is equipped with, A substrate coupled to the outer tube and extending along the outer tube, having a flexible region and a proximal region between the flexible region and the hub, Electrical wiring extending along the substrate, wherein the wiring is arranged in a twisted pair configuration in the proximal region and in a linear configuration in the flexible region, A coil sensor is coaxially positioned around the outer tube between the flexible region and the cutting tip, and is configured to electrically communicate with the electrical wiring and to detect changes in the electric field induced by the navigation system. A cutting accessory equipped with the following features.

2. The substrate is further coupled to an insulating spacer which is coaxially arranged around the outer tube, The cutting accessory according to claim 1, wherein the coil sensor is arranged coaxially around the insulating spacer.

3. The cutting accessory according to claim 2, further comprising an insulating layer coaxially arranged around the coil sensor.

4. The substrate further comprises a distal ring extending from the flexible region and coaxially arranged around the outer tube, The cutting accessory according to claim 1, wherein the coil sensor is arranged coaxially around the distal ring.

5. The cutting accessory according to any one of claims 1 to 4, further comprising a sheath coaxially arranged around the substrate and the coil sensor, wherein the sheath is optionally made of a heat-shrinkable material.

6. The cutting accessory according to any one of claims 1 to 5, wherein the twisted pair configuration includes a pair of electrical wirings arranged in complementary linear sections on the upper and lower surfaces of the substrate that are opposite to each other, the linear sections being separated by vias through which each of the pair of electrical wirings is routed between the upper and lower surfaces.

7. The cutting accessory according to claim 6, wherein the spacing between the vias is in the range of 2.3 to 3.3 millimeters.

8. The cutting accessory according to claim 7, wherein the linear configuration includes a pair of electrical wires arranged in complementary linear paths on the upper and lower surfaces of the substrate that are opposite to each other.

9. The cutting accessory according to any one of claims 1 to 8, wherein the substrate is elongated, and the width of the flexible region is narrower than the width of the proximal region.

10. The substrate further comprises a distal region extending from the flexible region, The cutting accessory according to claim 9, further comprising a coil pad disposed in the distal region, which provides electrical communication between the electrical wiring and each end of the coil sensor.

11. The cutting accessory according to claim 10, wherein the width of the distal region is wider than the width of the flexible region, and optionally, the width of the distal region is wider than the width of the proximal region.

12. The cutting accessory according to claim 11, wherein the width of the flexible region is 2 millimeters or less, the width of the proximal region is 3 millimeters or less, and / or the width of the distal region is 4 millimeters or less.

13. A proximal pad disposed in the proximal region of the substrate, A cable including a wire coupled to the proximal pad, wherein the cable is configured to be coupled to the console of the navigation system. A cutting accessory according to any one of claims 1 to 12, further comprising:

14. The cutting accessory according to any one of claims 1 to 13, wherein the coil sensor is positioned at a distance calibrated from the characteristic portion of the cutting tip.

15. The cutting accessory according to any one of claims 1 to 14, wherein the drive shaft is a cutting tube defining a suction lumen, the cutting tip is a cutting window, and the feature portion is the distal or central point of the cutting window.

16. The cutting accessory according to any one of claims 1 to 14, wherein the cutting tip is a bar head, and the feature portion is the distal or central point of the bar head.

17. The outer tube has a bent portion, The drive shaft is configured to transmit torque through the bent portion, The cutting accessory according to any one of claims 1 to 16, wherein at least a portion of the axial length of the flexible region of the substrate corresponds to the bent portion of the outer tube.

18. The outer tube comprises a flexible region formed from a flexible material, The drive shaft is configured to transmit torque through the flexible region, The cutting accessory according to any one of claims 1 to 16, wherein at least a portion of the axial length of the flexible region of the substrate corresponds to the bendable region of the outer tube.

19. Cutting accessories for powered surgical instruments used with a navigation system, A hub configured to be detachably coupled to the handpiece of the powered surgical instrument, An outer tube extending from the hub, A drive shaft is coaxially and rotatably arranged inside the outer tube, A cutting tip positioned at the distal end of the drive shaft, A sensor assembly configured to be electronically communicative with the aforementioned navigation system and The sensor assembly is equipped with, A substrate coupled to the outer tube and extending along the outer tube, Electrical wiring extending along the aforementioned substrate, A coil sensor comprising a conductive wire coaxially wound around the outer tube and positioned at a calibrated distance proximal to the characteristic portion of the cutting tip, wherein the coil sensor is configured to electrically communicate with the electrical wiring and to detect changes in the electric field induced by the navigation system, A sheath coaxially arranged around the substrate and the coil sensor A cutting accessory equipped with the following features.

20. The cutting accessory according to claim 19, further comprising an insulating layer coaxially arranged around the coil sensor.

21. The cutting accessory according to claim 19, wherein the substrate further comprises a distal ring coaxially arranged around the outer tube, and the coil sensor is coaxially arranged around the distal ring.

22. Cutting accessories for powered surgical instruments used with a navigation system, A hub configured to be detachably coupled to the handpiece of the powered surgical instrument, An outer tube extending from the hub, A drive shaft is coaxially and rotatably arranged inside the outer tube, A cutting tip positioned at the distal end of the drive shaft, A sensor assembly configured to be electronically communicative with the aforementioned navigation system and The sensor assembly is equipped with, A substrate coupled to the outer tube and extending along the outer tube, Electrical wiring extending along the aforementioned substrate, An insulating spacer, coupled to the substrate and coaxially arranged around the outer tube, A coil sensor coaxially arranged around the insulating spacer, wherein the coil sensor is configured to electrically communicate with the electrical wiring and to detect changes in the electric field induced by the navigation system, and A cutting accessory equipped with the following features.

23. The cutting accessory according to claim 22, further comprising a sheath coaxially arranged around the substrate and the coil sensor, wherein the sheath is optionally made of a heat-shrinkable material.

24. The cutting accessory according to claim 23, wherein the substrate is arranged radially between the coil sensor and the sheath.

25. Cutting accessories for powered surgical instruments used with a navigation system, A hub configured to be detachably coupled to the handpiece of the powered surgical instrument, An outer tube extending from the hub and having a bendable portion or a bendable region, A drive shaft coaxially and rotatably disposed within the outer tube, configured to transmit torque through the bend or the bendable region, A cutting tip positioned at the distal end of the drive shaft, A sensor assembly configured to be electronically communicative with the aforementioned navigation system and The sensor assembly is equipped with, A substrate coupled to the outer tube and extending along the outer tube, wherein the substrate comprises a proximal region and a flexible region, the width of the flexible region being smaller than the width of the proximal region, and at least a portion of the flexible region of the substrate being aligned with the bend or the bendable region of the outer tube, Electrical wiring extending along the aforementioned substrate, A coil sensor is coaxially positioned around the outer tube between the flexible region and the cutting tip, wherein the coil sensor is configured to electrically communicate with the electrical wiring and to detect changes in the electric field induced by the navigation system. A cutting accessory equipped with the following features.

26. The cutting accessory according to any one of claims 1 to 25, wherein the substrate is formed from polyimide.

27. The cutting accessory according to any one of claims 1 to 26, wherein the coil sensor comprises a wound conductive wire, the number of turns being in the range of approximately 150 to 2200 turns.

28. The cutting accessory according to claim 27, wherein the number of turns is in the range of approximately 500 to 600 turns.

29. Cutting accessories for powered surgical instruments used with a navigation system, A hub configured to be detachably coupled to the handpiece of the powered surgical instrument, An outer tube extending from the hub, A drive shaft is coaxially and rotatably arranged inside the outer tube, A cutting tip positioned at the distal end of the drive shaft, A sensor assembly configured to be electronically communicative with the navigation system, wherein the sensor assembly comprises a coil sensor coaxially arranged around the outer tube, and the coil sensor is formed from gauge wire and number of turns to provide sensor sensitivity that compensates for the material properties of the outer tube and the drive shaft, and A cutting accessory equipped with the following features.

30. The cutting accessory according to claim 29, wherein the sensor sensitivity is selectively adjusted based on the axial position of the coil sensor on the outer tube.

31. The cutting accessory according to claim 30, wherein the sensor sensitivity is reduced by an amount that increases as the coil sensor gets closer to the cutting tip.

32. The cutting accessory according to claim 30, wherein the sensor sensitivity is in the range of approximately 0.060 to 0.150 V / Hz / T, and optionally in the range of approximately 0.071 to 0.106 V / Hz / T.

33. The cutting accessory according to any one of claims 1 to 32, further comprising a radio frequency indicator tag having a memory that stores identification data and / or authentication data indicating the characteristics of the type of cutting accessory.

34. The cutting accessory according to claim 33, wherein the hub comprises a proximal housing defining a recess, and the radio frequency identification tag is disposed within the recess.

35. A method for assembling cutting accessories for powered surgical instruments used with a navigation system, The steps include preparing an insulating tube, or cutting the insulating tube to a length corresponding to the design length of the coil sensor, The steps include winding a conductive wire around the insulating tube to form the coil sensor, The steps include: preparing the substrate including electrical wiring bonded to the substrate; The steps include fixing the insulating tube to the substrate, The steps include establishing electrical communication between the coil sensor and the electrical wiring of the substrate, The steps include oriented the insulating tube and the coil sensor coaxially so that they are positioned on the outer tube of the cutting accessory, The steps of fixing the substrate to the outer tube and Methods that include...

36. The method according to claim 35, wherein the step of fixing the substrate to the outer tube further includes the step of thermally shrinking a sheath coaxially around the substrate and the coil sensor.

37. The method according to claim 35, further comprising the step of thermally shrinking an insulating layer coaxially around the coil sensor after the step of winding the conductive wire.

38. The method according to claim 37, further comprising the step of thermally shrinking a sheath coaxially around the substrate and the insulating layer.

39. The method according to any one of claims 35 to 38, wherein the step of establishing electrical communication between the coil sensor and the electrical wiring further includes the step of soldering the coil end to the electrical wiring.

40. The outer tube of the cutting accessory includes a bend or a bendable region. The method according to any one of claims 35 to 39, further comprising the step of aligning at least a portion of the flexible region of the substrate with the bent portion or the bendable region of the outer tube.

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