Linear position sensor assemblies for surgical instruments such as robotic bone drills

Abstract

A surgical instrument includes a base, a platform fixed to the base, three magnets supported by the platform and longitudinally spaced along a translation axis, a translation housing movable relative to the base along the translation axis, a tool extending distally from the translation housing wherein movement of the translation housing moves the tool along the translation axis, and at least one sensor fixed within and movable with the translation housing along the translation axis with the translation housing. The at least one sensor is configured to sense a magnetic field produced by the first, second, and third magnets. The sensed magnetic field varies based upon a position of the translation housing along the translation axis such that a position of the tool relative to the base is determinable based upon an output of the at least one sensor.

Description

A0013193LINEAR POSITION SENSOR ASSEMBLIES FOR SURGICAL INSTRUMENTS SUCH AS ROBOTIC BONE DRILLS

[0001] This application claims the benefit of U.S. Provisional Patent Application Serial No. 63 / 726,828, filed 2 December 2024, the entire content of which is incorporated herein by reference.FIELD

[0002] The present disclosure relates to surgical instruments and, more particularly, to linear position sensor assemblies for surgical instruments such as robotic bone drills.BACKGROUND

[0003] Surgical cutting instruments such as, for example, bone drills, include cutting tools, e.g., blades, burs, etc., connected to motorized drive assemblies for driving rotation of the cutting tools to perform a variety of surgical cutting procedures, e.g., bone cutting. In addition to rotational driving, some surgical cutting tools are capable of being advanced and / or retracted to a desired depth.

[0004] More recently, surgical robotic systems have been developed to assist a surgeon or other practitioner in carrying out a surgical procedure, such as a surgical cutting procedure. These surgical robotic systems may include one or more computer-controlled robotic arms enabling manipulation and actuation of one or more surgical instruments mounted thereon. Such surgical robotic systems may operate autonomously, e.g., without practitioner input during operation; semi- autonomously, e.g., with some practitioner input during operation; or non-autonomously, e.g., only as directed by a practitioner.SUMMARY

[0005] As used herein, the term “distal” refers to the portion that is being described which is closure to the surgical site, while the term “proximal” refers to the portion that is being described which is farther from the surgical site. Terms including “generally,” “about,” “substantially,” and the like, as utilized herein, are meant to encompass variations, e.g., manufacturing tolerances, material tolerances, use and environmental tolerances, measurement variations, design variations, and / or other tolerances and variations, up to and including plus or minus 10 percent. Further, to the extent consistent, any or all of the aspects detailed herein may be used in conjunction with any or all of the other aspects detailed herein.A0013193

[0006] Provided in accordance with aspects of the present disclosure is a surgical instrument including a base, a platform fixed to the base, and first, second, and third magnets supported by the platform and longitudinally spaced along a translation axis. The first and third magnets define a first polarity orientation and the second magnet is disposed between the first and second magnets and defines a second, opposite polarity orientation. The surgical instrument further includes a translation housing movable relative to the base along the translation axis, a tool coupled to and extending distally from the translation housing, and at least one sensor fixed within the translation housing. Movement of the translation housing along the translation axis moves the tool along the translation axis; likewise, the at least one sensor is movable along the translation axis with the translation housing. The at least one sensor is configured to sense a magnetic field produced by the first, second, and third magnets. The sensed magnetic field varies based upon a position of the translation housing along the translation axis such that a position of the tool relative to the base is determinable based upon an output of the at least one sensor.

[0007] In an aspect of the present disclosure, at least one of the first, second, or third magnets is disposed at a different height perpendicular to the translation axis relative to at least one other of the first, second, or third magnets.

[0008] In another aspect of the present disclosure, the at least one sensor includes first and second sensors disposed on opposing sides of and equally spaced from the translation axis.

[0009] In still another aspect of the present disclosure, the at least one sensor is an integrated circuit (IC) mounted on a sensor board.

[0010] In yet another aspect of the present disclosure, the translation housing is sealed to inhibit fluid ingress into the translation housing.

[0011] In another aspect of the present disclosure, a first motor is disposed within the translation housing and coupled to the tool such that activation of the first motor drives rotation of the tool relative to the base. The first motor is configured to translate with the translation housing.

[0012] In yet another aspect of the present disclosure, a cable connects to the translation housing and includes at least one electrical connector configured to establish electrical communication with the first motor.

[0013] In still another aspect of the present disclosure, the at least one sensor is disposed between the cable and the first motor along the translation axis.A0013193

[0014] In still yet another aspect of the present disclosure, the at least one sensor is mounted on a sensor board disposed within the translational housing. The sensor board defines at least one pass-through to enable the at least one electrical connector to extend from the cable, through the sensor board, to the first motor.

[0015] In another aspect of the present disclosure, a second motor is disposed on the base. The second motor is configured to drive translation of the translation housing along the translation axis relative to the base.

[0016] In another aspect of the present disclosure, the second motor is coupled to the translation housing via a lead screw coupled to the second motor and a lead screw collar coupled to the translation housing. The second motor is configured drive rotation of the lead screw to thereby translate the lead screw collar along the lead screw.

[0017] In still another aspect of the present disclosure, a rotary encoder is configured to sense a rotational position of the second motor. Alternatively or additionally, the rotary encoder is configured to enable redundant determination of a position of the tool relative to the base.

[0018] In another aspect of the present disclosure, a cannula assembly including an outer sheath extends distally from the base. The tool extends through the outer sheath and is movable relative thereto in response to translation of the translation housing.

[0019] Another surgical instrument provided in accordance with aspects of the present disclosure includes a base, a platform fixed to the base, first, second, and third magnets supported by the platform and longitudinally spaced along a translation axis, a translation housing movable relative to the base along the translation axis between a first position and a second position, a cable having a first end connected to the base and a second end connected to the translation housing such that the second end of the cable is movable with the translation housing between the first and second positions, a tool coupled to and extending distally from the translation housing such that translation of the translation housing between the first position and the second position moves the tool between a retracted position and an extended position, and at least one sensor fixed within the translation housing. The at least one sensor is movable along the translation axis with the translation housing and is configured to sense a magnetic field produced by the first, second, and third magnets. The sensed magnetic field varies based upon a position of the translation housing along the translation axis such that a position of the tool relative to the base is determinable based upon an output of the at least one sensor.A0013193

[0020] In an aspect of the present disclosure, at least one of the first, second, or third magnets is disposed at a different height perpendicular to the translation axis relative to at least one other of the first, second, or third magnets. Alternatively or additionally, the first and third magnets define a first polarity orientation while the second magnet is disposed between the first and second magnets and defines a second, opposite polarity orientation. Further, the at least one sensor may be an integrated circuit (IC) mounted on a sensor board.

[0021] In another aspect of the present disclosure, the translation housing is sealed to inhibit fluid ingress into the translation housing.

[0022] In still another aspect of the present disclosure, a first motor is disposed within the translation housing and configured to translate with the translation housing. The first motor is couple the tool and the cable. The cable includes at least one electrical connector configured to establish electrical communication with the first motor. Activation of the first motor drives rotation of the tool relative to the base.

[0023] In yet another aspect of the present disclosure, the at least one sensor is disposed between the cable and the first motor along the translation axis.

[0024] In still yet another aspect of the present disclosure, the at least one sensor is mounted on a sensor board disposed within the translational housing. The sensor board defines at least one pass-through to enable the at least one electrical connector to extend from the cable and through the sensor board.

[0025] In another aspect of the present disclosure, a second motor is disposed on the base and configured to drive translation of the translation housing between the first and second positions. In such aspects, a rotary encoder may be configured to sense a rotational position of the second motor. The rotary encoder may further be configured to enable redundant determination of a position of the tool relative to the base.

[0026] In yet another aspect of the present disclosure, a cannula assembly including an outer sheath extending distally from the base is provided. The tool extends through the outer sheath and is movable relative thereto in response to translation of the translation housing.BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The above and other aspects and features of the present disclosure will become more apparent in light of the following detailed description when taken in conjunction with the accompanying drawings wherein like reference numerals identify similar or identical elements.A0013193

[0028] FIG. 1 is a schematic illustration of a robotic surgical system in accordance with the present disclosure;

[0029] FIG. 2A is a front, perspective view of a surgical instrument provided in accordance with the present disclosure and configured for use with the robotic surgical system of FIG. 1 ;

[0030] FIG. 2B is a front, perspective view of the surgical instrument of FIG. 2 A with a cover removed to illustrate internal components of the surgical instrument;

[0031] FIG. 3 is an enlarged, side, perspective view of a portion of the surgical instrument of FIG. 2A with the cover removed;

[0032] FIGS. 4A and 4B are side views of the surgical instrument of FIG. 2 A with the cover removed and with a tool translation assembly disposed in first and second positions, respectively;

[0033] FIG. 5 is a longitudinal, cross-sectional view of a portion of the surgical instrument of FIG. 2A illustrating a sensor board disposed within a movable housing of the tool translation assembly of the surgical instrument;

[0034] FIG. 6 is a perspective view of the sensor board of FIG. 5;

[0035] FIGS. 7A and 7B are perspective and longitudinal, cross-sectional views, respectively, of a magnet assembly of the surgical instrument of FIG. 2A;

[0036] FIG. 8 is a longitudinal, cross-sectional view of another magnet assembly configured for use with the surgical instrument of FIG. 2A;

[0037] FIGS. 9A and 9B are longitudinal, cross-sectional views of a portion of the surgical instrument of FIG. 2A with the tool translation assembly disposed in the first and second positions, respectively; and

[0038] FIG. 10 is a graph of experimental results in accordance with the present disclosure of sensor output voltage difference versus linear position for the surgical instrument of FIG. 2A.DETAILED DESCRIPTION

[0039] Turning to FIG. 1, a robotic surgical system in accordance with the present disclosure is shown generally identified by reference numeral 100. Robotic surgical system 100 is shown in use for performing one or more surgical procedures on a patient “P” lying on an operating table “T”. Robotic surgical system 100 includes a robotic base 110, a robotic arm 120 coupled to robotic base 110, and a surgical instrument 200 configured to releasably connect to robotic arm 120 for performing one or more robotic-assisted surgical procedures on the patient “P”. Robotic base 110A0013193 supports robotic arm 120 and may be configured, for example, as a wheeled cart (as shown), tablemounted support, or any other suitable base supporting robotic arm 120.

[0040] Robotic arm 120 includes a plurality of linkages 122 interconnected with one another and / or robotic base 110 by a plurality of joints 124. Robotic arm 120 further includes a bone connection link 130 connecting the patient “P” to an attachment location 132 on robotic arm 120. In aspects, robotic arm 120 includes a base portion 126 disposed between bone connection link 130 and robotic base 110 and an arm portion 128 disposed between bone connection link 130 and surgical instrument 200. The linkages 122 and / or joints 124 of base portion 126 and arm portion 128 may define different degrees of freedom, ranges of motion, etc. An instrument adapter 134 of robotic arm 120 is disposed at the free end of arm portion 128 to enable releasable engagement of surgical instrument 200 with robotic arm 120. Surgical instrument 200 is described in detail hereinbelow as a bone drill, although other suitable surgical instruments are also contemplated for use with robotic surgical system 100.

[0041] With reference to FIGS. 2A-4B, surgical instrument 200 is shown. Surgical instrument 200 is a bone drill configured for use with robotic surgical system 100 (FIG. 1) or any other suitable robotic surgical system. Alternatively or additionally, surgical instrument 200 may be configured to releasably connect to a handpiece, or form at least a portion of a handpiece, as part of a handheld surgical instrument. Further, although surgical instrument 200 is detailed as a bone drill, the aspects and features of the present disclosure are equally applicable for use with other suitable surgical instruments, whether robotic or handheld.

[0042] Surgical instrument 200 includes a base 210, a cover 220, a cannula assembly 230, a tool 240, an irrigation assembly 250, a tool translation assembly 260, a tool rotational drive assembly 280, and a linear position sensor assembly 290. Base 210 includes an interface 212 configured to mechanically engage and electrically connect with instrument adapter 134 of robotic arm 120 of robotic surgical system 100 (FIG. 1) to enable robotic surgical system 100 (FIG. 1) to communicate with, power, and control surgical instrument 200. Cover 220 cooperates with base 210 to define a proximal housing of surgical instrument 200 that encloses the internal operable components thereof, e.g., tool translation assembly 260 and tool rotational drive assembly 280.

[0043] Cannula assembly 230 includes a proximal hub 232 configured to releasably engage, e.g., in threaded engagement, a distal nose 214 of base 210 to thereby engage cannula assembly 230 with base 210, e.g., to enable removal and / or replacement of cannula assembly 230.A0013193Alternatively, cannula assembly 230 may be integrally formed with base 210. Cannula assembly 230 further includes an elongated sheath 234 extending from proximal hub 232.

[0044] Tool 240 defines a rotating shaft 242 and an end effector 244. In aspects, tool 240 further includes an outer shaft (not shown) within which rotating shaft 242 is configured to rotate. Tool 240 may also include a proximal hub 248 configured to releasably couple tool 240 to base 210, e.g., to enable replacement of tool 240 with another tool of similar or different configuration. Alternatively, tool 240 may be integrally formed with base 210.

[0045] Shaft 242 of tool 240, when tool 240 is engaged with base 210, extends from base 210 through elongated sheath 234 of cannula assembly 230. End effector 244 is disposed at the distal end of shaft 242 and includes, for example, a cutting bur (e.g., fluted, abrasive-coated, etc.), a cutting blade (e.g., serrated, straight-edged, etc.), or any other suitable feature(s) configured to achieve a tissue effect (e.g., cutting tissue such as bone). Tool 240 is coupled to tool translation assembly 260 within the housing defined by base 210 and cover 220 to enable translation of tool 240 relative to base 210 and elongated sheath 234 of cannula assembly 230 between a retracted position (FIG. 4A), wherein end effector 244 is disposed within or in closer proximity to elongated sheath 234, and an extended position (FIG. 4B), wherein end effector 244 extends from or is further displaced from elongated sheath 234. Further, tool 240 is coupled to tool rotational drive assembly 280 within the housing defined by base 210 and cover 220 to enable rotational driving of tool 240 to thereby achieve the tissue effect (e.g., cutting tissue such as bone).

[0046] Irrigation assembly 250 includes first and second fluid ports 252, 254 disposed on base 210 and an internal fluid flow path (not shown) extending through base 210 to fluidly couple first and second fluid ports 252, 254. First fluid port 252 is configured to connect to tubing (not shown) connected to an irrigation source (not shown). Irrigation assembly 250 further includes tubing 256 configured to connect second fluid port 254 to a fluid port 236 of proximal hub 232 of cannula assembly 230 to thereby establish fluid communication between tubing 256 and an internal annular space defined between shaft 242 of tool 240 and elongated sheath 234 of cannula assembly 230 (or between an outer sleeve (not shown) of tool 240 and elongated sheath 234 of cannula assembly 230, where tool 240 includes an outer sleeve). In either configuration, irrigation assembly 250 thus defines a fluid flow path from the irrigation source (not shown) to the distal end of elongated sheath 234, thus enabling the delivery of irrigation fluid to facilitate the surgical procedure, e.g., cutting tissue such as bone. As an alternative to delivering irrigation fluid, first fluid port 252 mayA0013193 be connected to a source of vacuum to enable irrigation assembly 250 to be utilized to withdraw, e.g., suction, fluid from the surgical site through the internal annular space.

[0047] Continuing with reference to FIGS. 1-4B, tool translation assembly 260, as noted above, is configured to translate tool 240 relative to base 210 and elongated sheath 234 of cannula assembly 230 between the retracted position (FIG. 4A), wherein end effector 244 is disposed within or in closer proximity to elongated sheath 234, and the extended position (FIG. 4B), wherein end effector 244 extends from or is further extended from elongated sheath 234. This translation of tool 240 relative to base 210 and elongated sheath 234 enables end effector 244 of tool 240 to be positioned relative to base 210 and elongated sheath 234 at any suitable position between the retracted and extended positions (FIGS. 4A and 4B, respectively). This positioning of end effector 244 of tool 240 may be utilized to allow end effector 244 of tool 240 to reach tissue to be cut, to define a cutting depth limit, and / or for any other suitable purpose(s).

[0048] Tool translation assembly 260 includes a motor 262 disposed within base 210, a drive shaft 264 coupled to motor 262 such that motor 262 drives rotation of drive shaft 264, and a lead screw 266 operably coupled to drive shaft 264 such that activation of motor 262 drives rotation of drive shaft 264 to, in turn, drive rotation of lead screw 266. Motor 262 is electrically coupled with interface 212 of base 210 such that, with base 210 connected with instrument adapter 134 of robotic arm 120 of robotic surgical system 100 (FIG. 1), robotic surgical system 100 (FIG. 1) is able to communicate power and control signals to motor 262 to activate motor 262 to extend or retract tool 240 to a desired position. In aspects, motor 262 includes a rotary encoder 263 configured to sense a rotational position of the output rotor of motor 262 and, thus, enable determination of the position of tool 240 relative to base 210 and elongated sheath 234. Rotary encoder 263 may communicate, for example, with robotic surgical system 100 (FIG. 1), e.g., via interface 212, to communicate the position of tool 240 to robotic surgical system 100 (FIG. 1) (or enable determination of the position of tool 240 via robotic surgical system 100 (FIG. 1)) for tracking purposes, display purposes, operational feedback purposes, to enable / disable features, and / or for any other suitable purpose. Alternativity or additionally, rotary encoder 263 may communicate with a remote console (not shown), navigation system, etc., via wired or wireless communication, to enable determination of the position of tool 240 for the above-noted purposes and / or for any other suitable purpose.A0013193

[0049] Lead screw 266 may be operably coupled to drive shaft 264 via a direct connection or, as shown, via one or more meshed gears 268. In configurations where gears 268 are provided, the gears 268 may be configured to amplify, attenuate, or maintain the rotation of lead screw 266 relative to the rotation of drive shaft 264.

[0050] Referring still to FIGS. 1-4B, tool translation assembly 260 further includes a translation body 270 including a lead screw collar 272 disposed in threaded engagement about lead screw 266, a movable housing 274, and a guide collar 276 slidably disposed about a guide shaft 216 fixed to base 210. Translation body 270 may be monolithically formed as a single component, e.g., via molding, or otherwise configured such that, due to the threaded engagement of lead screw collar 272 about lead screw 266, activation of motor 262 translates translation body 270 along lead screw 266 and guide shaft 216 and relative to base 210. The translation of movable housing 274, e.g., between a first or proximal position (FIG. 4A) and a second or distal position (FIG. 4B), in turn, translates tool 240 between its retracted position (FIG. 4A) and its extended position (FIG. 4B). The slidable positioning of guide collar 276 about guide shaft 216 guides translation of translation body 270 and inhibits rotation of translation body 270 relative to base 210.

[0051] Tool rotational drive assembly 280 includes a cable 282 and a motor 284. Cable 282 is connected, at a fixed, first end thereof, to interface 212 of base 210 and at a second, opposite end thereof, to movable housing 274 of translation body 270. Cable 282 defines sufficient slack to enable the second, opposite end thereof to move with translation body 270 and relative to the fixed, first end of cable 282 between the first or proximal position (FIG. 4A) and the second or distal position (FIG. 4B). The second end of cable 282, more specifically, extends into movable housing 274 of translation body 270 to electrically connect to motor 284. Thus, with base 210 connected with instrument adapter 134 of robotic arm 120 of robotic surgical system 100 (FIG. 1), robotic surgical system 100 (FIG. 1) is able to communicate power and control signals to motor 284. Cable 282 further carries control wires to connect sensor board 292 (and, in particular, sensors 294 thereof) of linear position sensor assembly 290 with interface 212 of base 210 to enable linear position information sensed by linear position sensor assembly 290 to be communicated, for example, to robotic surgical system 100 (FIG. 1) to communicate the position of tool 240 to robotic surgical system 100 (FIG. 1) (or enable determination of the position of tool 240 via robotic surgical system 100 (FIG. 1)) for tracking purposes, display purposes, operational feedback purposes, to enable / disable features, and / or for any other suitable purpose. Alternativity orA0013193 additionally, the linear position information may be communicated to a remote console (not shown), navigation system, etc., via wired or wireless communication, to enable determination of the position of tool 240 for the above-noted purposes and / or for any other suitable purpose. Linear position sensor assembly 290 is described in greater detail below.

[0052] Motor 284 is fixed relative to and extends distally from movable housing 274 of translation body 270. Motor 284 includes an output rotor configured to couple to a proximal end of shaft 242 of tool 240, e.g., when tool 240 is coupled with base 210. More specifically, the output rotor of motor 284 and the proximal end of shaft 242 of tool 240 are configured for rotationally fixed engagement with one another, e.g., via complementary geometric coupling interfaces, such that rotational driving of the output rotor of motor 284, e.g., in response to activation of motor 284, rotationally drives shaft 242 of tool 240 and, thus, end effector 244 of tool 240 to perform a surgical cutting operation, e.g., bone cutting. Further, with motor 284 fixed relative to movable housing 274 of translation body 270 and, in turn shaft 242 of tool 240 engaged with motor 284, motor 284 and shaft 242 are moved together with translation body 270 between the first or proximal position of translation body 270 corresponding to the retracted position of shaft 242 of tool 240 (FIG. 4A), and the second or distal position of translation body 270 corresponding to the extended position of shaft 242 of tool 240 (FIG. 4B). Thus, motor 284 is operable to drive rotation of tool 240 to perform a surgical cutting operation at any suitable position of tool 240 between the retracted and extended positions (FIGS. 4A and 4B, respectively).

[0053] Referring still to FIGS. 1-4B, and with additional reference to FIGS. 5-7B and 9A-9B, linear position sensor assembly 290 includes a sensor board 292, e.g., a printed circuit board (PCB), mounted within movable housing 274 of translation body 270, two (or more) sensors 294 disposed on sensor board 292, and a magnet assembly 295 fixed relative to base 210 and including a plurality of magnets 296a-296c longitudinally spaced-apart along at least a portion of the translational travel path of translation body 270. Sensor board 292 may include a plurality of pass- through apertures 293 configured to enable passage of the power and / or communication lines, e.g., wires, pins, receptacles, contacts, etc., extending between cable 282 and motor 284.

[0054] Continuing with reference to FIGS. 5-7B and 9A-9B, the two (or more) sensors 294 may be configured as Hall Effect sensors 294 or other suitable sensors configured to sense a magnetic field or other electromagnetic property, e.g., as a result of the position(s) of sensors 294 relative to magnets 296a-296c. In aspects, at least two sensors 294 are provided; the two or moreA0013193 sensors 294 may be transversely aligned, substantially perpendicularly relative to the translational path of translation body 270, although other suitable numbers and configurations of sensors 294 are also contemplated. Further, sensors 294 may be inverted relative to one another (e.g., wherein sensors 294 are oriented 180 degrees offset relative to one another) and / or are equidistant from the longitudinal axis of translation body 270 (which, in turn, may correspond to the longitudinal axis of motor 284) on either side thereof. Likewise, sensors 294 may be equidistant from the longitudinal axis of magnet assembly 295. Sensors 294 may alternatively or additionally be configured as integrated circuits (ICs), e.g., IC Hall Effect sensors, disposed on sensor board 292.

[0055] With respect to configurations wherein sensors 294 are Hall Effect sensors, for example, the Hall Effect sensors are configured to produce signals, e.g., voltages, related to the magnetic field produced by magnets 296a-296c for output to robotic surgical system 100 (FIG. 1) or other suitable control device, e.g., via cable 282 and interface 212. Thus, with sensors 294 fixed relative to translation body 270 and magnets 296a-296c fixed relative to base 210, the signals, e.g., voltages, output by sensors 294 vary based upon the position of translation body 270 relative to base 210, thus enabling determination of the position of translation body 270 relative to base 210 and, accordingly, the position of tool 240 relative to base 210 and / or elongated sheath 234.

[0056] Magnet assembly 295, as noted above, is fixed relative to base 210 and includes a plurality of magnets 296a-296c. Magnet assembly 295, more specifically, includes a platform 298 supported above base 210, e.g., by a plurality of support screws 299, and extending longitudinally along base 210 in substantially parallel orientation relative to the translational travel path of translation body 270. Magnets 296a-296c are at least partially seated within platform 298 in longitudinally spaced relation along platform 298 and, thus, in longitudinal alignment along at least a portion of the translational travel path of translation body 270. Thus, as translation body 270 is translated relative to base 210, sensors 294 are translated relative to magnets 296a-296c such that the magnetic field of magnets 296a-296c sensed by sensors 294 varies based upon the longitudinal positions of sensors 294. The sensed magnetic field may be represented as a voltage output by sensors 294. In aspects, magnets 296a-296c are arranged with their polarity axes oriented longitudinally along the translational travel path of translation body 270 and with opposing polarity orientation relative to adjacent magnets 296a-296c. For example, and as shown in FIG. 6, magnet 296a may be oriented with its north “N” polarity end facing distally and its south “S” polarity end facing proximally; magnet 296b may be oriented with its south “S” polarity endA0013193 facing distally and its north “N” polarity end facing proximally; and magnet 296b may be oriented with its north “N” polarity end facing distally and its south “S” polarity end facing proximally. Although three (3) magnets 296a-296c are shown, it is also contemplated that more than three magnets may be provided, and in any suitable orientation. Likewise, although two sensors 294 are shown, it is also contemplated that one sensor or more than two sensors may be provided.

[0057] As shown in FIG. 7B, in aspects, magnets 296a-296c may be disposed at substantially the same vertical height relative to one another. Alternatively, with momentary reference to FIG.8, one or more of magnets 296a-296c, e.g., magnet 296a, may be offset to a different vertical height relative to one or more other magnets 296a-296c, e.g., magnets 296b and 296c. In configurations wherein one or more of magnets 296a-296c are offset to a different vertical height, a home position of translation body 270 can be readily distinguished. More specifically, the output voltage of sensors 294 is a local nominal maximum at the first or proximal position of translation body 270 (e.g., wherein sensors 294 are disposed in substantial vertical registration above magnet 296a (FIG. 9A)) as well as at the second or distal position of translation body 270 (e.g., wherein sensors 294 are disposed in substantial vertical registration above magnet 296c (FIG. 9B)). Further, in absolute terms, the output voltage of sensors 294 is at local absolute maximum at an intermediate position of translation body 270 between the first and second positions (e.g., wherein sensors 294 are disposed in vertical registration above magnet 296b) as well as at the first and second positions. The vertically raised position of magnet 296a relative to the vertical positions of magnets 296b, 296c, however, provides a different voltage maximum at the first position of translation body 270 compared to the second (and, in aspects, intermediate) position due to the closer proximity of magnet 296a relative to sensors 294. Thus, the voltage maximum at the first position can be distinguished based on magnitude (absolute or nominal), from the voltage maximum at the second (and, in aspects, the intermediate) position without requiring prior position information or change in magnetic field information.

[0058] Turning to FIG. 10, together with FIGS. 9 A and 9B, graph 1000 illustrates experimental results of the nominal and absolute voltage difference outputs of the one or more sensors 294 (in voltage units of Volts (V)) as a function of translation distance of translation body 270 (in distance units of millimeters (mm)). As shown by graph 1000, substantially equal voltage differences are sensed for the local absolute maxima corresponding to the first and intermediate positions of translation body 270. The end of the graph approaches another local absolute maximumA0013193 corresponding to the second position, but ends prior to actually reaching the second position. As detailed above, these local maxima can be distinguished by vertically raising or lowering one or more of magnets 296a-296c relative to one another such that these local maxima have distinguishable voltage differentials. Alternatively, as also noted above, prior data can be utilized to determine the direction of travel of translation body 270 and / or prior positions thereof, thus enabling distinction of the local maxima positions.

[0059] Referring generally to FIGS. 1-10, as detailed above, surgical instrument 200 includes two independent position sensors for enabling determination of the position of tool 240 relative to base 210, a rotary position sensor (e.g., rotary encoder 263) and a linear position sensor (e.g., linear position sensor assembly 290), thus providing redundant position sensing. However it is also contemplated that only linear position sensor assembly 290 be provided, where redundant sensing is not required. Further, linear position sensor assembly 290 is advantageous in that, sensor board 292 including sensors 294 may be sealed within translation body 270 such that sensor board 292, along with motor 284, are isolated from fluid exposure. Further, sensors 294 are able to sense the position of translation body 270, via interaction with magnet assembly 295 in contactless fashion such that the sealed translation body 270 is not compromised to enable sensing. In addition, magnet assembly 295 is not sensitive to fluid.

[0060] The techniques of this disclosure may also be described in the following examples.

[0061] Example 1. A surgical instrument, comprising: a base; a platform fixed to the base; first, second, and third magnets supported by the platform and longitudinally spaced along a translation axis, wherein the first and third magnets define a first polarity orientation and wherein the second magnet is disposed between the first and second magnets and defines a second, opposite polarity orientation; a translation housing movable relative to the base along the translation axis; a tool coupled to and extending distally from the translation housing, wherein movement of the translation housing along the translation axis moves the tool along the translation axis; and at least one sensor fixed within the translation housing such that the at least one sensor is movable along the translation axis with the translation housing, the at least one sensor configured to sense a magnetic field produced by the first, second, and third magnets, wherein the sensed magnetic field varies based upon a position of the translation housing along the translation axis such that a position of the tool relative to the base is determinable based upon an output of the at least one sensor.A0013193

[0062] Example 2. The surgical instrument according to example 1 , wherein at least one of the first, second, or third magnets is disposed at a different height perpendicular to the translation axis relative to at least one other of the first, second, or third magnets.

[0063] Example 3. The surgical instrument according to example 1 or 2, wherein the at least one sensor includes first and second sensors disposed on opposing sides of and equally spaced from the translation axis.

[0064] Example 4. The surgical instrument according to any one of examples 1-3, wherein the at least one sensor is an integrated circuit (IC) mounted on a sensor board.

[0065] Example 5. The surgical instrument according to any one of examples 1-4, wherein the translation housing is sealed to inhibit fluid ingress into the translation housing.

[0066] Example 6. The surgical instrument according to any one of examples 1-5, further comprising a first motor disposed within the translation housing and coupled to the tool such that activation of the first motor drives rotation of the tool relative to the base, the first motor configured to translate with the translation housing.

[0067] Example 7. The surgical instrument according to example 6, further comprising a cable connected to the translation housing, the cable including at least one electrical connector configured to establish electrical communication with the first motor.

[0068] Example 8. The surgical instrument according to example 7, wherein the at least one sensor is disposed between the cable and the first motor along the translation axis.

[0069] Example 9. The surgical instrument according to example 7 or 8, wherein the at least one sensor is mounted on a sensor board disposed within the translational housing, the sensor board defining at least one pass-through to enable the at least one electrical connector to extend from the cable, through the sensor board, to the first motor.

[0070] Example 10. The surgical instrument according to any one of examples 6-9, further comprising a second motor disposed on the base, the second motor configured to drive translation of the translation housing along the translation axis relative to the base.

[0071] Example 11. The surgical instrument according to example 10, wherein the second motor is coupled to the translation housing via a lead screw coupled to the second motor and a lead screw collar coupled to the translation housing, wherein the second motor is configured drive rotation of the lead screw to thereby translate the lead screw collar along the lead screw.A0013193

[0072] Example 12. The surgical instrument according to example 10 or 11, further comprising a rotary encoder configured to sense a rotational position of the second motor.

[0073] Example 13. The surgical instrument according to example 12, wherein the rotary encoder is configured to enable redundant determination of a position of the tool relative to the base.

[0074] Example 14. The surgical instrument according to any one of examples 1-13, further comprising a cannula assembly including an outer sheath extending distally from the base, wherein the tool extends through the outer sheath and is movable relative thereto in response to translation of the translation housing.

[0075] Example 15. A surgical instrument, comprising: a base; a platform fixed to the base; first, second, and third magnets supported by the platform and longitudinally spaced along a translation axis; a translation housing movable relative to the base along the translation axis between a first position and a second position; a cable having a first end connected to the base and a second end connected to the translation housing, wherein the second end of the cable is movable with the translation housing between the first and second positions; a tool coupled to and extending distally from the translation housing, wherein movement of the translation housing between the first position and the second position moves the tool between a retracted position and an extended position; and at least one sensor fixed within the translation housing such that the at least one sensor is movable along the translation axis with the translation housing, the at least one sensor configured to sense a magnetic field produced by the first, second, and third magnets, wherein the sensed magnetic field varies based upon a position of the translation housing along the translation axis such that a position of the tool relative to the base is determinable based upon an output of the at least one sensor.

[0076] Example 16. The surgical instrument according to example 15, wherein at least one of the first, second, or third magnets is disposed at a different height perpendicular to the translation axis relative to at least one other of the first, second, or third magnets.

[0077] Example 17. The surgical instrument according to example 15 or 16, wherein the first and third magnets define a first polarity orientation and wherein the second magnet is disposed between the first and second magnets and defines a second, opposite polarity orientation.

[0078] Example 18. The surgical instrument according to any one of examples 15-17, wherein the at least one sensor is an integrated circuit (IC) mounted on a sensor board.A0013193

[0079] Example 19. The surgical instrument according to any one of examples 15-18, wherein the translation housing is sealed to inhibit fluid ingress into the translation housing.

[0080] Example 20. The surgical instrument according to any one of examples 15-19, further comprising a first motor disposed within the translation housing, the first motor configured to translate with the translation housing and couple the tool and the cable, wherein the cable includes at least one electrical connector configured to establish electrical communication with the first motor, and wherein activation of the first motor drives rotation of the tool relative to the base.

[0081] Example 21. The surgical instrument according to example 20, wherein the at least one sensor is disposed between the cable and the first motor along the translation axis.

[0082] Example 22. The surgical instrument according to any one of examples 15-21 , wherein the at least one sensor is mounted on a sensor board disposed within the translational housing, the sensor board defining at least one pass-through to enable the at least one electrical connector to extend from the cable and through the sensor board.

[0083] Example 23. The surgical instrument according to any one of examples 15-22, further comprising a second motor disposed on the base, the second motor configured to drive translation of the translation housing between the first and second positions.

[0084] Example 24. The surgical instrument according to example 23, further comprising a rotary encoder configured to sense a rotational position of the second motor.

[0085] Example 25. The surgical instrument according to example 24, wherein the rotary encoder is configured to enable redundant determination of a position of the tool relative to the base.

[0086] Example 26. The surgical instrument according to any one of examples 15-25, further comprising a cannula assembly including an outer sheath extending distally from the base, wherein the tool extends through the outer sheath and is movable relative thereto in response to translation of the translation housing.

[0087] While several aspects of the disclosure are detailed above and shown in the drawings, it is not intended that the disclosure be limited thereto, as it is intended that the disclosure be as broad in scope as the art will allow and that the specification be read likewise. Therefore, the description and drawings should not be construed as limiting, but merely as exemplifications of particular aspects. Those skilled in the art will envision other modifications within the scope and spirit of the claims.

Claims

A0013193WHAT IS CLAIMED IS:

1. A surgical instrument, comprising: a base (210); a platform (298) fixed to the base (210); first, second, and third magnets (296a-296c) supported by the platform (298) and longitudinally spaced along a translation axis, wherein the first and third magnets (296a, 296c) define a first polarity orientation and wherein the second magnet (296b) is disposed between the first and second magnets (296a, 296c) and defines a second, opposite polarity orientation; a translation housing (274) movable relative to the base (210) along the translation axis; a tool (240) coupled to and extending distally from the translation housing (274), wherein movement of the translation housing (274) along the translation axis moves the tool (240) along the translation axis; and at least one sensor (294) fixed within the translation housing (274) such that the at least one sensor (294) is movable along the translation axis with the translation housing (274), the at least one sensor (294) configured to sense a magnetic field produced by the first, second, and third magnets (296a-296c), wherein the sensed magnetic field varies based upon a position of the translation housing (274) along the translation axis such that a position of the tool (240) relative to the base (210) is determinable based upon an output of the at least one sensor (294).

2. The surgical instrument according to claim 1, wherein at least one of the first, second, or third magnets (296a-296c) is disposed at a different height perpendicular to the translation axis relative to at least one other of the first, second, or third magnets (296a-296c).

3. The surgical instrument according to any preceding claim, wherein the at least one sensor (294) includes first and second sensors (294) disposed on opposing sides of and equally spaced from the translation axis.

4. The surgical instrument according to any preceding claim, wherein each of the at least one sensors (294) is an integrated circuit (IC) mounted on a sensor board (292).A00131935. The surgical instrument according to any preceding claim, wherein the translation housing (274) is sealed to inhibit fluid ingress into the translation housing (274).

6. The surgical instrument according to any preceding claim, further comprising a first motor (284) disposed within the translation housing (274) and coupled to the tool (240) such that activation of the first motor (284) drives rotation of the tool (240) relative to the base (210), the first motor (284) configured to translate with the translation housing (274).

7. The surgical instrument according to claim 6, further comprising a cable (282) connected to the translation housing (274), the cable (282) including at least one electrical connector configured to establish electrical communication with the first motor (284).

8. The surgical instrument according to claim 7, wherein the at least one sensor (294) is disposed between the cable (282) and the first motor (284) along the translation axis.

9. The surgical instrument according to claim 7 or 8, wherein the at least one sensor (294) is mounted on a sensor board (292) disposed within the translational housing (274), the sensor board (292) defining at least one pass-through to enable the at least one electrical connector to extend from the cable (282), through the sensor board (292), to the first motor (284).

10. The surgical instrument according to any one of claims 7-9, wherein the cable (282) has a first end connected to the base (210) and a second end connected to the translation housing (274), wherein the first end of the cable (282) is fixed relative to the base (210) and wherein the second end of the cable (282) is movable with the translation housing (274).

11. The surgical instrument according to any preceding claim, further comprising a second motor (262) disposed on the base (210), the second motor (262) configured to drive translation of the translation housing (274) along the translation axis relative to the base (210).

12. The surgical instrument according to claim 11, wherein the second motor (262) is coupled to the translation housing (274) via a lead screw (266) coupled to the second motor (262) and a leadA0013193 screw collar (272) coupled to the translation housing (274), wherein the second motor is configured drive rotation of the lead screw (266) to thereby translate the lead screw collar (272) along the lead screw (266).

13. The surgical instrument according to claim 11 or 12, further comprising a rotary encoder (263) configured to sense a rotational position of the second motor (262).

14. The surgical instrument according to claim 13, wherein the rotary encoder (263) is configured to enable redundant determination of a position of the tool (240) relative to the base (210).

15. The surgical instrument according to any preceding claim, further comprising a cannula assembly (230) including an outer sheath (234) extending distally from the base (210), wherein the tool (240) extends through the outer sheath (234) and is movable relative thereto in response to translation of the translation housing (274).

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