Flexible tissue sampling mechanism

Abstract

A medical system including a flexible tissue sampling mechanism having a cannula and a stylet disposed within the cannula. The medical system includes at least one sensor configured to generate sensor data indicating a shape of the flexible tissue sampling mechanism. Additionally, the medical system includes a drive mechanism configured to generate a drive force that varies based on the sensor data to advance the cannula relative to the stylet to take a tissue sample.

Description

PATENT APPLICATIONATTY. DOCKET NO.: 33685 / 70328 / PCFLEXIBLE TISSUE SAMPLING MECHANISMCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] Priority is claimed to United States Provisional Patent Application No. 63 / 687,604, filed August 27, 2024, the entire contents of which are here incorporated by reference herein.FIELD OF THE INVENTION

[0002] The present disclosure relates to medical tools and, more particularly, to a flexible tissue sampling mechanism.BACKGROUND

[0003] Minimally invasive medical techniques are intended to reduce the amount of tissue that is damaged during medical procedures, thereby reducing patient recovery time, discomfort, and harmful side effects. Such minimally invasive techniques may be performed through natural orifices in a patient anatomy or through one or more surgical incisions. Through these natural orifices or incisions clinicians may insert minimally invasive medical instruments (including surgical, diagnostic, and / or therapeutic instruments) to reach a target tissue location. One such minimally invasive technique is to use a flexible and / or steerable elongate device, such as a flexible catheter that can be inserted into anatomic passageways and navigated toward a region of interest within the patient anatomy. Medical tools, such as biopsy instruments, may be deployed through the catheter to perform a medical procedure at the region of interest.SUMMARY

[0004] Disclosed herein is a medical system. The medical system includes a flexible tissue sampling mechanism including a cannula and a stylet disposed within the cannula. The medical system also includes at least one sensor configured to generate sensor data indicating a shape of the flexible tissue sampling mechanism. The medical system also includes a drive mechanism configured to generate a drive force that varies based on the sensor data to advance the cannula relative to the stylet to take a tissue sample.

[0005] In some variations, the medical system also includes a flexible elongate device including the at least one sensor. The flexible elongate device includes a channel through whichPATENT APPLICATIONATTY. DOCKET NO.: 33685 / 70328 / PC the flexible tissue sampling mechanism is inserted and the flexible tissue sampling mechanism conforms to shape of the channel. Additionally, the flexible tissue sampling mechanism is movable within the channel relative to the flexible elongate device. In some examples, the flexible tissue sampling mechanism includes the at least one sensor.

[0006] In other variations, the drive mechanism includes a spring, motor, or pneumatic actuator. Additionally, the drive mechanism can be operably coupled to the cannula of the tissue sampling mechanism.

[0007] In yet other variations, the medical system also includes a control system. The control system can receive the sensor data from the at least one sensor and operate the drive mechanism to generate the drive force based on the sensor data. Additionally, the control system can be configured to determine, based on the sensor data, the drive force that results in a target velocity of the cannula relative to the stylet. In such examples, the drive force generated by the drive mechanism can be adjusted based on the sensor data. Additionally, the drive force can be manually adjusted. In such an example, the control system is configured to provide an indication that varies based on the sensor data to the user for the manual adjustment. Alternatively, the drive force can be automatically adjusted. In the foregoing variations, adjustment of the drive force includes setting a force profile of the drive force along the stroke of the cannula relative to the stylet.

[0008] In other variations, the control system can calculate a bend angle of the flexible tissue sampling mechanism based on the sensor data and can determine the drive force based on the bend angle. Additionally, the control system can determine an accumulated curvature of the flexible tissue sensor system and can determine the drive force based on the accumulated curvature. In the foregoing examples, the control system can calculate a bend angle of the flexible elongate device based on the sensor data and determine the drive force based on the bend angle.

[0009] In some variations, the at least one sensor includes a shape sensor. Additionally, the at least one sensor can include a plurality of position sensors positioned at different locations. In some examples, the sensor is carried by the flexible elongate device and / or the tissue sampling mechanism. The flexible elongate device can be a catheter or endoscope.

[0010] In some other variations, the tissue sampling mechanism also includes a sheath at least partly surrounding the cannula and stylet. The sheath can also include a sheath cap.PATENT APPLICATIONATTY. DOCKET NO.: 33685 / 70328 / PC

[0011] Also disclosed herein is a medical system including a flexible tissue sampling mechanism. The flexible tissue sampling mechanism includes a cannula having a cutting surface and a channel. The flexible tissue sampling mechanism also includes a stylet having a tissue sampling notch, the stylet being at least partially disposed in the channel such that the stylet and the cannula are moveable relative to each other. Additionally, the flexible tissue sampling mechanism includes a first alignment surface disposed on one of the cannula and the stylet and a second alignment surface disposed on the other one of the cannula and the stylet. The first alignment surface and the second alignment surface being in physical contact with each other such that the cannula and the stylet are limited in rotational movement relative to each other.

[0012] In some variations, the first alignment surface is a tongue and the second alignment surface is a groove configured to slidably receive the tongue. In some examples, the tongue and groove have a T-shaped cross section. Additionally, the tongue can engage a hard stop disposed at an end of the groove.

[0013] In other variations, the first alignment surface includes a non-circular exterior surface and the second surface includes a nesting, complementary non-circular exterior surface. In one example, the cross-sectional shape of the first alignment surface are ovular.

[0014] In yet other variations, the alignment mechanism radially aligns a cannula tip and a stylet tip relative to a central longitudinal axis. In such examples, the stylet can include a predetermined curve bias. Additionally, the predetermined curve can bend the stylet inward, away from the tissue sampling notch.

[0015] In further variations, the medical system also includes a sheath defining a second channel. The sheath can include a sheath cap disposed on the distal end of the sheath. In some examples, the sheath cap is made of metal. In some other examples, at least one of the sheath, cannula, and or stylet are made from or lined with a low-friction material such as a fluoropolymer, Polytetrafluoroethylene (PTFE), stainless steel, parylene.

[0016] In other variations, the cannula can include a laser cut cannula shaft including a first portion having a first density of laser cuttings and a second portion can have a second density of laser cuttings. The first density can be different than the second density. In some examples, the second portion can be disposed on the distal portion of the cannula shaft and the second density is less than the first density.PATENT APPLICATIONATTY. DOCKET NO.: 33685 / 70328 / PC

[0017] Also disclosed herein is a medical system including a flexible tissue sampling mechanism. The flexible tissue sampling mechanism can include a flexible cannula having a cannula shaft and a cutting surface distal to the flexible cannula shaft. The cannula can also define a channel. The flexible tissue sampling mechanism can also include a flexible stylet including a stylet shaft and a stylet tip distal to the stylet shaft. The stylet shaft can at least partially be disposed in the channel. The stylet and the cannula can be moveable relative to each other to take a tissue sample. Additionally, the medical system can include a cannula control including: a drive mechanism operably coupled to the cannula shaft; and an axial limiter mechanism. The axial limiter can be configured to, during the relative movement of the stylet and cannula to take a tissue sample, limit extension of the cutting surface beyond a target point proximal to a distal end of the stylet tip.

[0018] In some variations, the axial limiter includes a damper. The damper can include a shock absorber or a viscoelastic material. In various examples, the damper is disposed within or on a handle of the medical system.

[0019] In other variations, the axial limiter includes a tongue and groove. The tongue can engage an end stop of the groove. Additionally, the tongue can be disposed on one of the cannula and the stylet and the groove is disposed on the other of the cannula and the stylet.

[0020] In yet other variations, the axial limiter includes a laser cut cannula shaft to axially stiffen a distal portion of the cannula shaft. The cannula shaft can include a first portion having a first density of laser cuttings and a second portion having a second density of laser cuttings, the first density different than the second density. In such examples, the second portion can be disposed on the distal portion of the cannula shaft and the second density is less than the first density.

[0021] In further variations, the axial limiter mechanism can include an electrical motor. The motor can control a cannula deceleration. Additionally, the motor can be disposed within or on a handle of the medical system.BRIEF DESCRIPTION OF DRAWINGS

[0022] The present disclosure is described in the following detailed description in conjunction with the drawings, wherein:

[0023] FIG. 1 is a schematic diagram for a robotically-assisted manipulator system, according to some examples.PATENT APPLICATIONATTY. DOCKET NO.: 33685 / 70328 / PC

[0024] FIG. 2A is a schematic diagram of an instrument system according to examples described herein.

[0025] FIG. 2B illustrates a distal portion of the instrument system of FIG. 2A with an extended example of an instrument according to examples described herein.

[0026] FIG. 3 is a perspective view of a medical device according to examples described herein.

[0027] FIG. 4 is a perspective, partially exploded view of a tissue sampling device such as a biopsy tool constructed in accordance with the present disclosure.

[0028] FIG. 5 is a perspective view of one version of a stylet and cannula of the biopsy tool of FIG. 4.

[0029] FIG. 6 is a side view of the stylet and cannula of FIG. 5.

[0030] FIG. 7A is a perspective view of another version of a stylet and cannula of a biopsy stool constructed in accordance with the present disclosure.

[0031] FIG. 7B is a close-up perspective view of the modified stylet and cannula of FIG. 7A.

[0032] FIG. 8 is a front view of another modified stylet and cannula constructed in accordance with the present disclosure.

[0033] FIG. 9 is a side view of another modified stylet constructed in accordance with the present disclosure.

[0034] FIG. 10 is a side view of a stylet made in accordance with the present disclosure.

[0035] FIG. 1 1 is a side view of a modified cutting surface configured for use with the biopsy tool of FIG. 4.

[0036] FIG. 12 is a side view of a modified cutting surface configured for use with the biopsy tool of FIG. 4.

[0037] FIG. 13 is a side view of a modified stylet constructed in accordance with the present disclosure.

[0038] FIG. 14 is a side view of a modified stylet constructed in accordance with the present disclosure.PATENT APPLICATIONATTY. DOCKET NO.: 33685 / 70328 / PC

[0039] FIG. 15 is a side view of a cannula shaft with a modified laser cut pattern constructed in accordance with the present disclosure.

[0040] FIG. 16 is a side view of a cannula shaft with a modified laser cut pattern constructed in accordance with the present disclosure.

[0041] FIG. 17 is a side view of a cannula shaft with a modified laser cut pattern constructed in accordance with the present disclosure.

[0042] FIG. 18 is a side view of a modified stylet and cannula constructed in accordance with the present disclosure.

[0043] FIG. 19 is a perspective view of a modified handle configured for use with the biopsy tool of FIG. 4 constructed in accordance with the present disclosure.

[0044] FIG. 20 is a top view of a modified handle configured for use with the biopsy tool of FIG. 4 constructed in accordance with the present disclosure.

[0045] FIG. 21 is a top view of a modified handle configured for use with the biopsy tool of FIG. 4 constructed in accordance with the present disclosure.

[0046] Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions and / or relative positioning of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of various embodiments of the present invention. Also, common but well-understood elements that are useful or necessary in a commercially feasible embodiment are often not depicted in order to facilitate a less obstructed view of these various embodiments. It will further be appreciated that certain actions and / or steps may be described or depicted in a particular order of occurrence while those skilled in the art will understand that such specificity with respect to sequence is not actually required. It will also be understood that the terms and expressions used herein have the ordinary technical meaning as is accorded to such terms and expressions by persons skilled in the technical field as set forth above except different specific meanings have otherwise been set forth herein.DETAILED DESCRIPTION

[0047] Aspects of this disclosure herein can be part of a computer-assisted teleoperational manipulator system, sometimes referred to as a robotically-assisted manipulatorPATENT APPLICATIONATTY. DOCKET NO.: 33685 / 70328 / PC system or a robotic system. The manipulator system can include one or more manipulators that can be operated with the assistance of an electronic controller (e.g., computer) to move and control functions of one or more instruments when coupled to the manipulators.

[0048] FIG. 1 illustrates an embodiment of a robotically-assisted manipulator system for use with the tools described herein. The manipulator system can be used, for example, in surgical, diagnostic, therapeutic, biopsy, or non-medical procedures, and is generally indicated by the reference numeral 100. As shown in FIG. 1 , a robotically-assisted manipulator system 100 can include one or more manipulator assemblies 102 for operating one or more medical instrument systems 104 in performing various procedures on a patient P positioned on a table T in a medical environment 101 . For example, the manipulator assembly 102 can drive catheter or end effector motion, can apply treatment to target tissue, and / or can manipulate control members. The manipulator assembly 102 can be teleoperated, non-teleoperated, or a hybrid teleoperated and non-teleoperated assembly with select degrees of freedom of motion that can be motorized and / or teleoperated and select degrees of freedom of motion that can be nonmotorized and / or non-teleoperated. An operator input system 106, which can be inside or outside of the medical environment 101 , generally includes one or more control devices for controlling manipulator assembly 102. Manipulator assembly 102 supports medical instrument system 104 and can optionally include a plurality of actuators or motors that drive inputs on medical instrument system 104 in response to commands from a control system 112. The actuators can optionally include drive systems that when coupled to medical instrument system 104 can advance medical instrument system 104 into a naturally or surgically created anatomic orifice. Other drive systems can move the distal end of medical instrument in multiple degrees of freedom, which can include three degrees of linear motion (e.g., linear motion along the X, Y, Z Cartesian axes) and in three degrees of rotational motion (e.g., rotation about the X, Y, Z Cartesian axes). The manipulator assembly 102 can support various other systems for irrigation, treatment, or other purposes. Such systems can include fluid systems (including, for example, reservoirs, heating / cooling elements, pumps, and valves), generators, lasers, interrogators, and ablation components.

[0049] Robotically-assisted manipulator system 100 also includes a display system 110 for displaying an image or representation of the surgical site and medical instrument system 104 generated by an imaging system 109 which can include an imaging system, such as an endoscopic imaging system. Display system 110 and operator input system 106 can be oriented so an operator O can control medical instrument system 104 and operator input system 106PATENT APPLICATIONATTY. DOCKET NO.: 33685 / 70328 / PC with the perception of telepresence. A graphical user interface can be displayable on the display system 110 and / or a display system of an independent planning workstation.

[0050] In some examples, the endoscopic imaging system components of the imaging system 109 can be integrally or removably coupled to medical instrument system 104. However, in some examples, a separate imaging device, such as an endoscope, attached to a separate manipulator assembly can be used with medical instrument system 104 to image the surgical site. The endoscopic imaging system 109 can be implemented as hardware, firmware, software, or a combination thereof which interact with or are otherwise executed by one or more computer processors, which can include the processors of the control system 112.

[0051] Robotically-assisted manipulator system 100 can also include a sensor system 108. The sensor system 108 can include a position / location sensor system (e.g., an actuator encoder or an electromagnetic (EM) sensor system) and / or a shape sensor system (e.g., an optical fiber shape sensor) for determining the position, orientation, speed, velocity, pose, and / or shape of the medical instrument system 104. The sensor system 108 can also include temperature, pressure, force, or contact sensors or the like.

[0052] Robotically-assisted manipulator system 100 can also include a control system 112. Control system 112 includes at least one memory 116 and at least one computer processor 1 14 for effecting control between medical instrument system 104, operator input system 106, sensor system 108, and display system 110. Control system 112 also includes programmed instructions (e.g., a non-transitory machine-readable medium storing the instructions) to implement a procedure using the robotically-assisted manipulator system including for navigation, steering, imaging, engagement feature deployment or retraction, applying treatment to target tissue (e.g., via the application of energy), or the like.

[0053] Control system 112 can optionally further include a virtual visualization system to provide navigation assistance to operator O when controlling medical instrument system 104 during an image-guided surgical procedure. Virtual navigation using the virtual visualization system can be based upon reference to an acquired pre-operative or intra-operative dataset of anatomic passageways. The virtual visualization system processes images of the surgical site imaged using imaging technology such as computerized tomography (CT), magnetic resonance imaging (MRI), fluoroscopy, thermography, ultrasound, optical coherence tomography (OCT), thermal imaging, impedance imaging, laser imaging, nanotube X-ray imaging, and / or the like. The control system 1 12 can use a pre-operative image to locate the target tissue (using visionPATENT APPLICATIONATTY. DOCKET NO.: 33685 / 70328 / PC imaging techniques and / or by receiving user input) and create a pre-operative plan, including an optimal first location for performing treatment. The pre-operative plan can include, for example, a planned size to expand an expandable device, a treatment duration, a treatment temperature, and / or multiple deployment locations.

[0054] FIG. 2A shows a medical instrument system 200 according to some embodiments. In some embodiments, medical instrument system 200 can be used in an image- guided medical procedure. In some examples, medical instrument system 200 can be used for non-teleoperational exploratory procedures or in procedures involving traditional manually operated medical instruments, such as endoscopy. In some embodiments, medical instrument system 200 is interchangeable with, or a variation of, medical instrument system 104 of FIG. 1.

[0055] Medical instrument system 200 includes flexible elongate device 202, such as a flexible catheter or endoscope (e.g., gastroscope, bronchoscope), coupled to a drive unit 204. Flexible elongate device 202 includes a flexible body 216 having proximal end 217 and distal end, or tip portion, 218. In some embodiments, flexible body 216 has an approximately 14-20 mm outer diameter. Other flexible body outer diameters can be larger or smaller. Flexible body 216 can have an appropriate length to reach certain portions of the anatomy, such as the lungs, sinuses, throat, or the upper or lower gastrointestional region, when flexible body 216 is inserted into a patient’s oral or nasal cavity.

[0056] Medical instrument system 200 optionally includes a tracking system 230 for determining the position, orientation, speed, velocity, pose, and / or shape of distal end 218 and / or of one or more segments 224 along flexible body 216 using one or more sensors and / or imaging devices. The entire length of flexible body 216, between distal end 218 and proximal end 217, can be effectively divided into segments 224. Tracking system 230 can optionally be implemented as hardware, firmware, software, or a combination thereof which interact with or are otherwise executed by one or more computer processors, which can include the processors of control system 1 12 in Fig. 1 .

[0057] Tracking system 230 can optionally track distal end 218 and / or one or more of the segments 224 using a shape sensor 222. In some embodiments, tracking system 230 can optionally and / or additionally track distal end 218 using a position sensor system 220, such as an electromagnetic (EM) sensor system. Alternatively, the shape sensor 222 may include an optical fiber aligned with the flexible body 216 (e.g., provided within an interior channel of the flexibly body 216 or mounted externally along the flexible body 216). In some examples, thePATENT APPLICATIONATTY. DOCKET NO.: 33685 / 70328 / PC optical fiber may have a diameter of approximately 800 pm. In other examples, the diameter may be larger or smaller. The optical fiber of the shape sensor 222 may form a fiber optic bend sensor for determining the shape of flexible body 216. Optical fibers including Fiber Bragg Gratings (FBGs) may be used to provide strain measurements in structures in one or more dimensions. Various systems and methods for monitoring the shape and relative position of an optical fiber in three dimensions, which may be applicable in some examples, are described in U.S. Patent Application Publication No. 2006 / 0013523 (filed July 13, 2005 and titled “Fiber optic position and shape sensing device and method relating thereto”); U.S. Patent No. 7,772,541 (filed on March 12, 2008 and titled “Fiber Optic Position and / or Shape Sensing Based on Rayleigh Scatter”); and U.S. Patent No. 8,773,650 (filed on Sept. 2, 2010 and titled “Optical Position and / or Shape Sensing”), which are all incorporated by reference herein in their entireties. Sensors in some examples may employ other suitable strain sensing techniques, such as Rayleigh scattering, Raman scattering, Brillouin scattering, and Fluorescence scattering. In some examples, position sensor system 220 can be configured and positioned to measure six degrees of freedom, e.g., three position coordinates X, Y, Z and three orientation angles indicating pitch, yaw, and roll of a base point or five degrees of freedom, e.g., three position coordinates X, Y, Z and two orientation angles indicating pitch and yaw of a base point.

[0058] In some examples, the control system 112 calculates a bend angle of the flexible elongate device 202 based on the sensor system 222. Additionally, the control system 1 12 can calculate an accumulated curvature of the flexible elongate device 202.

[0059] In some examples, the shape of the flexible body 216 may be determined using other techniques. For example, a history of the position and / or pose of the distal end 218 of the flexible body 216 can be used to reconstruct the shape of flexible body 216 over an interval of time (e.g., as the flexible body 816 is advanced or retracted within a patient anatomy). Although the position sensor system 220 is shown as being near the distal end 218 of the flexible body 216 to track the distal end 218, the number and location of the position sensors of the position sensor system 220 may vary to track different regions along the flexible body 216. In one example, the position sensors include conductive coils that may be subjected to an externally generated electromagnetic field. Each coil of position sensor system 220 may produce an induced electrical signal having characteristics that depend on the position and orientation of the coil relative to the externally generated electromagnetic field. The position sensor system 220 may measure one or more position coordinates and / or one or more orientation angles associated with one or more portions of flexible body 216. In some examples, the positionPATENT APPLICATIONATTY. DOCKET NO.: 33685 / 70328 / PC sensor system 220 may be configured and positioned to measure six degrees of freedom, e.g., three position coordinates X, Y, Z and three orientation angles indicating pitch, yaw, and roll of a base point. In some examples, the position sensor system 220 may be configured and positioned to measure five degrees of freedom, e.g., three position coordinates X, Y, Z and two orientation angles indicating pitch and yaw of a base point. Further description of a position sensor system, which may be applicable in some examples, is provided in U.S. Patent No. 6,380,732 (filed August 11 , 1999 and titled “Six-Degree of Freedom Tracking System Having a Passive Transponder on the Object Being Tracked”), which is incorporated by reference herein in its entirety.

[0060] Flexible body 216 includes one or more channels 221 sized and shaped to receive one or more medical instruments 226. In some embodiments, flexible body 216 includes two channels 221 for separate instruments 226, however, a different number of channels 221 can be provided. FIG. 2B is a simplified diagram of flexible body 216 with medical instrument 226 extended according to some embodiments. In some embodiments, medical instrument 226 can be used for procedures and aspects of procedures, such as surgery, biopsy, ablation, mapping, imaging, illumination, irrigation, or suction. Medical instrument 226 can be deployed through channel 221 of flexible body 216 and used at a target tissue location within the anatomy. Medical instrument 226 can include, for example, image capture devices, biopsy instruments, ablation instruments, catheters, laser ablation fibers, and / or other surgical, diagnostic, or therapeutic tools. Medical tools can include end effectors having a single working member such as a scalpel, a blunt blade, a lens, an optical fiber, an electrode, and / or the like. Other end effectors can include, for example, forceps, graspers, balloons, needles, scissors, clip appliers, and / or the like. Other end effectors can further include electrically activated end effectors such as electrosurgical electrodes, transducers, sensors, imaging devices and / or the like. Medical instrument 226 can be advanced from the opening of channel 221 to perform the procedure and then retracted back into the channel when the procedure is complete. Medical instrument 226 can be removed from proximal end 217 of flexible body 216 or from another optional instrument port (not shown) along flexible body 216. The medical instrument 226 can be used with an image capture device (e.g., an endoscopic camera) also within the flexible elongate device 202. Alternatively, the medical instrument 226 can itself be the image capture device.

[0061] Medical instrument 226 can additionally house cables, linkages, or other actuation controls (not shown) that extend between its proximal and distal ends to controllablyPATENT APPLICATIONATTY. DOCKET NO.: 33685 / 70328 / PC the bend distal end of medical instrument 226. Flexible body 216 can also house cables, linkages, or other steering controls (not shown) that extend between drive unit 204 and distal end 218 to controllably bend distal end 218 as shown, for example, by broken dashed line depictions 219 of distal end 218. In some examples, at least four cables are used to provide independent “up-down” steering to control a pitch motion of distal end 218 and “left-right” steering to control a yaw motion of distal end 218. In embodiments in which medical instrument system 200 is actuated by a robotically-assisted assembly, drive unit 204 can include drive inputs that removably couple to and receive power from drive elements, such as actuators, of the teleoperational assembly. In some embodiments, medical instrument system 200 can include gripping features, manual actuators, or other components for manually controlling the motion of medical instrument system 200. The information from tracking system 230 can be sent to a navigation system 232 where it is combined with information from visualization system 231 and / or the preoperatively obtained models to provide the physician or other operator with real-time position information.

[0062] FIG. 3 includes another view of a medical device 300, according to an embodiment. In some embodiments, the medical device 300 or any of the components therein are optionally parts of an instrument for a surgical system that performs surgical procedures, and which surgical system can include a manipulator unit, a series of kinematic linkages, a series of cannulas, or the like. The medical device 300 (and any of the instruments described herein) can be used in any suitable surgical system, such as the manipulator system 100 or the medical instrument system 200 shown and described above. The medical device 300 can be used with the medical instruments 226, described above. As shown in FIG. 3, the medical device 300 defines (or is included within) a distal boundary (or footprint) that corresponds to a cannula size, or a size to fit within a working channel of a flexible elongate device (such as a flexible catheter or endoscope), or other size dictated by the surgical environment. The distal boundary can be a cylindrical shape having any suitable nominal diameter (e.g., 8 mm, 5 mm, or any size therebetween). The medical device 300 includes a force transmission mechanism 304, a shaft 306, and a set of tension elements (which can be, for example, a cable, band, or the like).

[0063] As shown in FIG. 3, the proximal force transmission mechanism 304 includes a set of drive components such as capstans 322 and 324 that rotate or “wind” a proximal portion of any of the tension elements to produce the desired tension element movement. In some embodiments, two proximal ends of a tension element, which are associated with opposingPATENT APPLICATIONATTY. DOCKET NO.: 33685 / 70328 / PC directions of a single degree of freedom, are connected to two independent drive capstans 322 and 324. This arrangement, which is generally referred to as an antagonist drive system, allows for independent control of the movement of (e.g., pulling in or paying out) each of the ends of the tension elements. The force transmission mechanism 304 may produce the desired articulation movements (pitch, yaw, or grip) of the shaft 306.

[0064] In some embodiments, the force transmission mechanism 304 can include any of the assemblies or components described in International Patent Application Serial No. PCT / US2022 / 039942, entitled “Surgical Instrument Cable Control and Routing Structures,” the disclosure of which is incorporated herein by reference in its entirety. In other embodiments, however, any of the medical devices described herein can have the two ends of a tension elements wrapped about a single capstan. This alternative arrangement, which is generally referred to as a self-antagonist drive system, operates the two ends of the tension element using a single drive motor.

[0065] Moreover, although the force transmission mechanism 304 is shown as including capstans, in other embodiments, a force transmission mechanism can include one or more linear actuators that produce translation (linear motion) of a portion of the cables. Such force transmission mechanisms can include, for example, a gimbal, a lever, or any other suitable mechanism to directly pull (or release) an end portion of any of the cables. For example, in some embodiments, the proximal force transmission mechanism 304 can include any of the proximal force transmission mechanisms or components described in U.S. Patent Application Pub. No. US 2015 / 0047454 A1 (filed Aug. 15, 2014), entitled “Lever Actuated Gimbal Plate,” or U.S. Patent No. US 6,817,974 B2 (filed Jun. 28, 2001 ), entitled “Surgical Tool Having Positively Positionable Tendon-Actuated Multi-Disk Wrist Joint,” each of which is incorporated herein by reference in its entirety.

[0066] The shaft 306 can be any suitable elongated shaft that is coupled to the force transmission mechanism 304. Specifically, the shaft 306 includes a proximal portion 326 that is coupled to the force transmission mechanism 304, and a distal portion 328. The shaft 306 defines a passageway or series of passageways through which various components can be routed from the force transmission mechanism 304. In some embodiments, the shaft 306 can be a substantially rigid shaft in other embodiments, the shaft 306 can be a flexible member.

[0067] A tissue sampling device (e.g., a biopsy tool), in accordance with the present disclosure, may be used to collect tissue sample (e.g., biopsy samples) from a patient toPATENT APPLICATIONATTY. DOCKET NO.: 33685 / 70328 / PC diagnose, for example, a benign or malignant lesion. Larger biopsy samples with more layers of intact tissue may be required to definitively diagnose a benign lesion than to diagnose a malignant lesion. If a large enough biopsy tissue sample is not collected, the patient may not receive a clear diagnosis of a suspicious lesion and may be subject to repeated and / or more invasive procedures. Conventional percutaneous devices for collecting lung biopsy samples from a patient typically include a rigid biopsy needle. A doctor guides the rigid biopsy needle from outside the patient's body, puncturing the patient’s skin, underlying tissue, and lungs to position the rigid biopsy needle at the lesion site to collect a sample.

[0068] A flexible robotic-assisted medical system, or other flexible medical device, may permit access to the lungs or other organs via different routes (e.g., endoluminally through a patient’s mouth, trachea, airway, etc.). However, conventional rigid biopsy tools may be incompatible with these medical systems and procedures. For example, lung biopsy procedures include inserting an elongated, flexible device with an internal channel (e.g., catheter, endoscope, laparoscope, etc.) into a patient’s mouth through the airway to a target tissue location (e.g., lesion) in the lungs. As such, a flexible biopsy tool is desirable to permit insertion through a narrow and sometimes tortuous internal channel of the elongate device to reach a distal opening of the elongate device at the target tissue location.

[0069] Furthermore, conventional biopsy tools include a sharp distal tip to collect a tissue sample at the target tissue location. In some instances, a sharp tip may damage the internal channel of the flexible device as the biopsy tool passes through the internal channel. More than one biopsy sample may be taken, so one or more biopsy tools may be inserted into and removed from the flexible device multiple times during a procedure. To prevent damage to the internal channel from the sharp tip as the biopsy tools pass through the channel in both directions, an outer protective sheath positioned between the biopsy tool and the surface of the internal channel can be used to shield the internal channel from the sharp tip.

[0070] In view of the above, described herein are designs for an improved flexible biopsy tool that is compatible with elongated flexible devices having an internal channel. In some examples, the flexible biopsy tool includes a flexible cannula having a distal end with a cutting surface. A flexible stylet disposed at least partially within the cannula extends from a distal end portion of the flexible cannula. The stylet may include an atraumatic tip at a distal end of the stylet that shields the cutting surface of the cannula when the cannula and the stylet are in a closed configuration. As such, when in the closed configuration, the flexible biopsy tool may traverse through an elongate device to a distal opening of the device without risk of damage toPATENT APPLICATIONATTY. DOCKET NO.: 33685 / 70328 / PC the internal channel. An outer protective sheath might not be used to protect the internal channel from the cutting surface of the biopsy tool in such an example, allowing the biopsy tool to be sized larger than biopsy tools that are used with outer sheaths.

[0071] Biopsy Tool including a flexible tissue sampling device

[0072] According to one example of the present disclosure, FIG. 4 shows a tissue sampling device including a biopsy tool 400 and FIGS. 5 and 6 illustrate an example flexible tissue sampling device. The biopsy tool 400 includes a flexible cannula 402 and a flexible stylet 404 at least partially received within a distal end portion of the flexible cannula 402. The biopsy tool 400 includes a handle portion 406 (discussed in greater detail below in connection with FIGS. 19-21 ) that the cannula 402 and flexible stylet 404 extend distally from. The handle portion 406 may be used to help guide the cannula 402 and stylet 404 through a flexible elongate device 408 and to control movement of the cannula 402 and / or stylet 404 to transition the biopsy tool 400 between open and closed configurations, as described in further detail below. The handle portion 406 may be manually controlled by a physician or may be at least partially controlled using a robotic-assisted system.

[0073] As shown in FIG. 4, a distal end portion 409 of the biopsy tool 400 may be inserted into a proximal opening 412 of the flexible elongate device 408 (e.g., catheter, endoscope, laparoscope, etc.) that has an internal channel 410 extending from the proximal opening 412 to a distal opening 413. In some examples, the distal opening 413 of the elongate device 408 may have been inserted into a patient, and the elongate device 408 may have been navigated through the patient to a target tissue location. For example, the elongate device 408 may be a flexible catheter and the distal opening 413 of the catheter may have been inserted into a patient’s airway and the catheter guided through the lungs to reach a suspicious lesion in the lungs. The flexible catheter may have a small diameter to allow the catheter to travel a tortuous path to reach the suspicious lesion, which may be located deep within the lungs. In some examples, the elongate device 408 may include an integrated imaging device or a separate imaging device to assist with navigation to the target tissue location. If a separate imaging device is used, the imaging device may be removed from the internal channel 410 of the elongate device 408 after the elongate device 408 is in an appropriate position and prior to insertion of the biopsy tool 400 in some examples.

[0074] It should be noted that the disclosure is not limited to examples where a catheter is inserted into a patient’s airway to access the target tissue location in the lungs, and anyPATENT APPLICATIONATTY. DOCKET NO.: 33685 / 70328 / PC elongate device may be inserted into a patient (via a natural opening, a surgical port, or through a patient’s skin) to access any organ or tissue location in the patient. Reference to a catheter and / or sheath throughout the disclosure may also refer to other elongate devices with internal channels, such as an endoscope, laparoscope, and / or any other appropriate device including a channel through which the biopsy needle may be passed.

[0075] The cannula 402 may be flexible to conform to the narrow (and sometimes tortuous) internal channel 410 of the flexible elongate device 408 that has been inserted into a patient and navigated to a target tissue location. As will be discussed below, in connection with FIGS. 15-17, the cannula 402 can include a plurality of slits 414 to increase the flexibility of the cannula 402. The plurality of slits 414 may form living hinges to provide flexibility to allow the cannula 402 to navigate the internal channel 410, which may be located deep within a patient’s lungs. In some examples, the plurality of slits 414 may extend to a proximal end of a cutting surface (discussed in greater detail in connection with FIG. 5) of the cannula 402. However, in other examples, the plurality of slits may end prior to a proximal end of the cutting surface. Examples of biopsy tools including slits are described in U.S. Patent Application No. 2020 / 0077991 , which is incorporated by reference herein in its entirety. Additionally, while a cannula including slits has been illustrated in the figure, other appropriate flexible constructions of the cannula are also contemplated including, for example, the use of flexible materials proximal to the cutting surface.

[0076] In some examples, the flexible elongate device 408 is similar to or identical to the flexible elongate device 202 described above in connection with FIGS. 2A-2B. As a result, the flexible elongate device 408 can include the shape sensor 222 as described above.

[0077] In some examples, the flexible elongate device 408 includes a sheath to protect the flexible elongate device 408 from the canula 402 and / or the stylet 402 tip. In some examples, the catheter 408 includes a sheath cap 415. The sheath cap 415 can be in the shape of an annular ring disposed around the internal channel 410 on the distal opening 413 of the catheter 408. The sheath cap 415 can be manufactured from a material that is harder than the cannula 402 and / or the stylet 404. In some examples, the sheath cap 415 is made of metal (e.g., steel, aluminum). As a result, the sheath cap 415 can protect the catheter from being cut by the cannula 402 and / or the stylet 404.

[0078] FIGS. 5 and 6 depict one version of a flexible tissue sampling mechanism 500 of the biopsy tool 400 of the present disclosure. The flexible tissue sampling mechanism 500PATENT APPLICATIONATTY. DOCKET NO.: 33685 / 70328 / PC illustrated in FIG. 6 is disposed in an open configuration. The flexible tissue sampling mechanism 500 includes a stylet 502 (corresponding to stylet 404 of FIG. 4) having a tip 504 and a sampling notch 505 to hold a tissue sample. The biopsy tool 400 using stylet 502 may be used with the sheath cap 415 to shield the tip 504 to prevent damage to an internal channel of a catheter or tissue. The flexible tissue sampling mechanism 500 also includes a cannula 506 (corresponding to the cannula 402 of FIG. 4) having a cutting surface 507 and a channel 508. The stylet 502 is disposed in the channel 508 and moveable relative to the cannula 506. In some examples, a shape sensor such as the shape sensor 222 discussed above with respect to FIG. 2A can be disposed on the flexible tissue sampling mechanism 500. For example, the shape sensor 222 can be disposed on one or both of the stylet 502 and the cannula 506.

[0079] The tip 504 of the stylet is a tri-bevel tip. The tri-bevel tip 504 includes three surfaces that extend distally from a sharp point at the distal end of the stylet 502. The tip 504 is configured to pierce tissue. In various examples, the tip 504 can include alternative tip geometries. For example, the tip 504 can be a conical tip, pyramidal tip, bevel tip, or any other stylet tip configuration.

[0080] The sampling notch 505 includes a spine 512 that extends between a proximal side 514 and a distal side 516 of the notch 505. The spine 512 is flexible in order to conform to a shape of the flexible cannula 506. Additionally, the spine 512 is sufficiently rigid to both facilitate the shearing off of tissue during a closing process and puncture tissue to collect a tissue sample. Dimensions of the spine 512 may affect the rigidity of the stylet 502 as well as the volume of the notch 505 to collect a target tissue sample. For example, increasing a thickness of the spine 512 may increase the rigidity of the stylet 502, but may also decrease the volume of the notch 505, limiting the size of the tissue sample collected by the biopsy tool 400. Similarly, increasing a length of the spine may increase a volume of the notch 505 while decreasing rigidity of the stylet 502. Thus, the dimensions of the spine 512 and notch 505 may be selected to balance the desired rigidity of the stylet 502 while still collecting a large enough target sample size.

[0081] The sampling notch 505 is configured to hold and stabilize target tissue in the sampling notch 505 when the drive mechanism fires the cannula 506 (described above). For example, the distal side 516 is angled and configured to allow tissue to enter the sample notch 505. Additionally, a vacuum source may apply a suction to at least a portion of the interior volume of the notch to bias a portion of target tissue into the notch.PATENT APPLICATIONATTY. DOCKET NO.: 33685 / 70328 / PC

[0082] In the examples described above, the catheter 408, the cannula 506 (e.g., cannula 402) and / or the stylet 502 (e.g., stylet 404) of a biopsy tool may be constructed of metal, plastic, a combination thereof, and / or any other appropriate material. For example, each of the catheter, cannula, and stylet may be made of metal (e.g., stainless steel, nitinol, any elastic biocompatible alloy, spiral cut stainless steel, coil pipe stainless steel, etc.). Alternatively, one of the catheter, cannula, stylet, or any combination of the catheter, cannula, and stylet may be made of a plastic (e.g., PEEK, nylon, polyethylene, etc.). Additionally or alternatively, the catheter, cannula, stylet, or any other component of a biopsy tool, as disclosed herein, can be made of a low-friction material, coated with a low-friction coating, or sheathed in a low-friction material. Low friction materials include, but are not limited to: stainless steel, Polyether ether ketone (PEEK); polyamide (nylon); polyethylene; ultra high molecular weight polyethylene (UHMW), polytetrafluoroethylene (PTFE), fluoropolymers, parylene. However, it should be understood that the cannula and / or stylet may be made of any material that provides sufficient flexibility to traverse through a narrow, tortuous catheter, while also being rigid enough to collect a tissue sample, and in some examples, puncture through tissue.

[0083] Once the biopsy tool 400 has navigated through the catheter 408 to the distal opening 413 of the catheter 408 and the tip 504 has been positioned adjacent a target tissue location, the biopsy tool 400 may be moved to an open configuration to expose a full length 522 of the sampling notch 505 formed in the stylet 502. The target tissue may be a suspicious lesion in a patient, such as in the lungs or other organ. Positioning the tip 504 proximate to the target tissue location may include puncturing through tissue to reach a suspicious lesion (e.g., an extraluminal lesion in the lungs). The biopsy tool 400 may be moved from the closed configuration to the open configuration by axially moving the cannula 506, the stylet 502, or both relative to one another until proximal end 514 of the sampling notch 505 is no longer enclosed in the channel 508 of the cannula 506. For example, in some versions, the stylet 502 may move distally relative to the cannula 506, the cannula 506 may move proximally relative to the stylet 502, or both the cannula and stylet may be moved in these opposing directions towards the open configuration. In the open configuration, the distal end portion 409 of the biopsy tool 400 may be positioned proximate a target tissue location to receive at least a portion of the target tissue into a volume of the notch 505. In some examples, the biopsy tool 400 may include or be connected to a vacuum source through a channel in the cannula and / or stylet to apply a suction at the sampling notch 505 to ensure a portion of the target tissue is well seated in the sampling notch 505. Once appropriately positioned, the biopsy tool 400 may be moved from the open configuration to the closed configuration, by actuating the cannula 506 until the tip 504 of thePATENT APPLICATIONATTY. DOCKET NO.: 33685 / 70328 / PC stylet 506 is at least partially enclosed in the channel 508 of the cannula 506. In other examples, the stylet 502 is moved within the channel 508 of the cannula 506 or both the cannula 506 and the stylet 502 are moved relative to each other. As the biopsy tool 400 moves to the closed configuration, the cutting surface 507 of the cannula 506 may shear off the portion of the target tissue in the notch 505. The sheared off tissue may thereafter be stored within the notch 505, which is enclosed by the cannula 506 in the closed configuration.

[0084] In various examples, the biopsy tool 400 includes a drive mechanism operably coupled to the cannula 506. The drive mechanism is operably coupled to the cannula 506 to generate a drive force for firing the cannula 506 (actuating the cannula 506). Firing the cannula 506 includes actuating the cannula 506 axially in the distal direction with sufficient force to shear off the target tissue disposed within the sampling notch 505. In the present example, the cannula 506 is actuated by releasing potential energy stored in a spring (described in greater detail in connection with FIG. 19). In various examples, the drive mechanism of the biopsy tool 400 includes spring, a servo, a motor, a robotic system, a pneumatic system, or any other appropriate actuator.

[0085] In some examples, the control system 112 is configured to receive sensor data generated by the shape sensor 222 disposed on at least one of the catheter 408, the stylet 502, and / or the cannula 506. In such an example, the control system 112 can control the drive mechanism to generate a drive force based on the sensor data. For example, if the shape sensor 222 generates data of a highly tortuous path, the control system 112 can increase the drive force generated by the drive mechanism. In some examples, the control system 112 is configured to determine a target velocity or target energy profile of the cannula 506 relative to the stylet 502 when the cannula 506 is transitioning the flexible tissue sampling mechanism to the closed configuration.

[0086] The biopsy tool 400 may then store the sheared off target tissue in the sampling notch 505, protected by the cannula 506 when in the closed configuration. The biopsy tool 400 may then be removed from the catheter to retrieve the target sample. The same or different biopsy tool may be inserted to retrieve multiple target tissue samples.

[0087] Variation of the flexible tissue sampling mechanism

[0088] FIGS. 7A and 7B depict an alternative flexible tissue sampling mechanism 700, disposed in a closed configuration in FIG. 7B, configured for use in the biopsy tool 400 of the present disclosure. The flexible tissue sampling mechanism 700 can maintain rotationalPATENT APPLICATIONATTY. DOCKET NO.: 33685 / 70328 / PC alignment between a cutting surface and a sampling notch; maintain radial alignment between the cutting surface and a stylet tip; and prevent the cutting surface from firing beyond the stylet tip. The flexible tissue sampling mechanism 700 includes a stylet 702 having a tip 704 and a sampling notch 705. Also shown in FIG. 7 is an alignment mechanism 710 including a first alignment surface 712 and a second alignment surface 714, but is otherwise substantially similar to the flexible tissue sampling mechanism 500 of FIGS. 5 and 6.

[0089] The first and second alignment surfaces 712, 714 are configured to reduce or eliminate radial misalignment of the cutting surface 707 relative to the sampling notch 705. The first alignment surface 712 is a groove 713 disposed along the length of the stylet 702 while the second alignment surface 714 is a tongue 715 disposed on the cannula 706. The first alignment surface 712 and the second alignment surface 714 are in physical contact with each other and limit the rotational movement of the first and second alignment surfaces 712, 714 relative to each other. As a result, the cutting surface 707 can remain aligned with the sampling notch 705.

[0090] In the present example, the tongue 715 has a semi-circular end and the groove 713 has a semi-circular cross-sectional shape. In various examples, the tongue 715 and the groove 713 have complementary shapes that facilitate smooth, linear actuation of the cannula 706 relative to the stylet 702. Additionally, the complementary shapes are sufficiently engaged with each other to restrict, limit, and / or prevent relative rotational displacement of the cannula 706 and stylet 702. In other examples, the tongue 715 and groove 713 may have different complementary shapes (e.g., square, trapezoidal, etc.).

[0091] In one example, the tongue 715 and the groove 713 may be T-shaped. In such an example, the tongue and groove 715, 713 limit relative rotational displacement of the cannula 706 relative to the stylet 702 and maintain axial alignment of the cutting surface 707 relative to the tip 704. As discussed above, the T-shaped tongue and groove 715, 713 rotational alignment between the cannula 706 and the stylet 702. Additionally, the T-shaped tongue and groove 715, 713 maintain axial alignment of the cutting surface 707 relative to the tip 704 because the lateral arms of the T-shaped tongue 715 can exert an aligning force on the stylet 702 via the lateral channels of the T-shaped groove 713. Accordingly, when the cannula 706 is fired and transitions the flexible tissue sampling mechanism 700 into a closed configuration, the cutting surface 707 does not fall out of axial alignment with the tip 704. If the cutting surface 707 falls out of axial alignment with the tip 704, the cutting surface can strike and, in some examples, gouge the tip 704. Maintaining axial alignment by exerting a radial force will bePATENT APPLICATIONATTY. DOCKET NO.: 33685 / 70328 / PC discussed in greater detail in connection with FIG. 14. Alternatively, the T-shape could be a dovetail or similar connection between the tongue and groove 715, 713.

[0092] To ensure the tongue 715 and groove 713 are engaged in both the open and closed configurations, the stylet 702 includes an elongate proximal body 722 to lengthen the groove 713. The elongate proximal body is monolithically or integrally formed with the stylet 702. The groove 713 extends along most of the length of the elongate proximal body 722. To ensure the stylet 702 can remain flexible and pass through tortuous paths in the body, the elongate proximal body 722 includes a kerf 724 (e.g., a recess, small notch, cut-out, etc.). Although the stylet 702 is shown with one kerf 724, in other examples, the elongate proximal body 722 could include two or more kerfs. Additionally or alternatively, the elongate proximal body 722 can be coupled to the stylet 702 and the elongate proximal body 722 can made of a highly flexible material and, in such an example, may not require the kerf 724.

[0093] Also shown in FIG. 7B is a stop 719 disposed at a distal end of the groove 713. The stop 719 engages the tongue 715 to limit axial movement of the cannula 706 relative to the stylet 702. The tongue 715, the groove 713, and the stop 719 together operate as an axial limiter, limiting axial movement of the cannula 706 relative to the stylet 702. As discussed above, the cannula 706 is fired when actuated by the drive mechanism (e.g., a spring). In response to the cannula 706 firing with the transferred energy from the drive mechanism, the kinetic energy of the cannula 706 and the cutting surface 707 is transferred into the stop 719. As a result, the cannula 706 and the cutting surface 707 have a controlled energy profile. Additionally, the cutting surface 707 stops at a predetermined target point 732. In some examples, the controlled energy profile is configured such that the cutting surface 707 does not extend beyond a target point on the tip 704. In some examples, the target point is the distal- most tip of the tip 704. But the target point could refer to any other desired location on the tip 704. In some examples, the controlled energy profile limits or prevents the cutting surface 707 from overshooting the tip 704.

[0094] Alternative variation of the flexible tissue sampling mechanism

[0095] FIG. 8 is a front view of another version of a flexible tissue sampling mechanism 800 including a flexible stylet 802 having a tip 804 and a cannula 806 having a cutting surface 807. The flexible tissue sampling mechanism 800 is substantially similar to the flexible tissue sampling mechanisms 500, 700 of FIGS. 5, 7A, 7B, but includes different alignment surfaces than the flexible tissue sampling mechanism 700 to prevent radial misalignment of a cuttingPATENT APPLICATIONATTY. DOCKET NO.: 33685 / 70328 / PC surface and a sampling notch. The stylet 802 includes a first alignment surface 812 and the cannula 806 includes a second alignment surface 814. In the present example, the first alignment surface 812 is an outer surface of the stylet 802 and the second alignment surface 814 is an inner surface of the cannula 806. The first and second alignment surfaces 812, 814 are nesting, complementary surfaces. As shown in FIG. 8, the first and second alignment surfaces 812, 814 are ovular. In various other examples, the first and second alignment surfaces 812, 814 are obround, elliptical, square, rectangular, hexagonal, or another shape other than a circle.

[0096] The first and second alignment surfaces 812, 814 engage one another to limit rotation of the cannula 806 relative to the stylet 802. Specifically, because the first and second alignment surfaces 812, 814 are non-circular, the stylet 802 and the cannula 806 cannot rotate relative to one another. The first alignment surface 812 and the second alignment surface 814 are in physical contact and nest with each other in order to limit the rotational movement of the first and second alignment surfaces 812, 814 relative to each other. As a result, the cutting surface 807 can remain aligned with the sampling notch (not shown) of the stylet 802.

[0097] Variations of the stylet of the flexible tissues sampling mechanism

[0098] FIG. 9 is a stylet arrangement 900 that is easier to operate with the biopsy tool 400 over the stylet arrangement 1000 of FIG. 10. In contrast to the stylet 1002 that needs to have the sampling notch 1005 aligned with the target tissue location for proper operation, the stylet 902, having a center spine 912 does not require directional alignment with the target tissue location. The stylet 902 includes a tip 904 (similar or identical to the tri-bevel tip 504 or tip 704), sampling notch 905, and a center spine 912. Because the center spine 912 is centrally disposed on the stylet 902, the sampling notch 905 can provide an annular sample or be placed against a portion of tissue in any direction. As shown in cross-sectional view A-A, the center spine 912 is shown as having a square cross-sectional shape, in various examples, the center spine 912 could be triangular, hexagonal, circular, or any other cross-sectional shape. In contrast, the stylet 1002, although including a similar tip 1004, includes a sampling notch 1005 partially defined by a side spine 1012. The stylet 1002 is substantially identical to the stylet 702. As shown in cross-sectional view B-B, the spine 1012 forms a segment of a circle cross- sectional shape. Because the spine 1012 is disposed on a side of the stylet 1002, the sampling notch 1005 is sensitive to radial alignment with a portion of tissue, but, in some examples, an annular tissue sample can be undesirable. Additionally, in some examples, it is easier to slide aPATENT APPLICATIONATTY. DOCKET NO.: 33685 / 70328 / PC tissue sample out of the sampling notch 1005 while the tissue sample may need to be cut to be removed from the sampling notch 905.

[0099] Variations of cutting surfaces of the cannula of the flexible tissue sampling mechanism

[0100] FIGS. 1 1 and 12 illustrate alternative cutting surfaces 1 102, 1202 that can be used with stylets 902, 1002 of FIGS. 9 and 10. Similar to the stylet arrangement 900, the alternative cutting surfaces 1 102, 1202 do not require rotational alignment with a target tissue location and a sampling notch (e.g., sampling notch 505, 705). The alternative cutting surfaces 1102, 1202 do not require rotational alignment because each of the cutting surfaces 1102, 1202 are circumferential (non-directional) cutting surfaces. For example, the cutting surface 1 102 is a three-prong Franseen tip that includes three prongs 1112 and a circumferential cutting surface 1114. Alternatively, the cutting surface 1202 is a two-prong fork tip having two prongs 1212 and a circumferential edge 1214. In various examples, the cutting surface 507, 707 could be replaced with either of the alternative cutting surfaces 1102, 1202. Although two-prong and three-prong alternative cutting surfaces 1 102, 1202 are shown, a wide variety of alternative cutting surfaces, having half-circumferential, three-quarter circumferential, or another alternative cutting surface arrangement with alternative prong arrangement.

[0101] The alternative cutting surfaces 1102, 1202 can be disposed on a cannula (e.g., cannula 506) and telescopically passed over a stylet (e.g., stylets 902, 1002). The firing of the cannula 506 having an alternative cutting surface 1102, 1202 is substantially similar to the firing of the cannula 506 described above. The alternative cutting surfaces 1102, 1202 allow for radial misalignment of the cutting surfaces 1102, 1202 and the stylet 902, 1002. Additionally, when one of the alternative cutting surfaces 1102, 1202 is used in connection with the stylet 902, the alternative cutting surfaces 1 102, 1202 can produce an annular tissue sample.

[0102] Additionally, in various examples, the biopsy tool 400 can be modified to operate using any of the stylets 902, 1002 and the cutting surfaces 1102, 1202. Additionally, the stylets 902, 1002 and the cutting surfaces 1102, 1202 can be modified to include the tongue and groove 715, 713 and stop 719 as described in connection with FIGS. 7 and 8.

[0103] Additional variations of stylets of the flexible tissue sampling mechanism

[0104] FIGS. 13 and 14 illustrate two modified stylets 1302, 1402 that can improve operation of the biopsy tool 400. The modified stylets 1302, 1402 overcome radial misalignmentPATENT APPLICATIONATTY. DOCKET NO.: 33685 / 70328 / PC between the cutting surface 507, 707 and the tip 1304, 1404. The modified stylets 1302, 1402 improve the interaction between a cutting surface (e.g., cutting surface 707) and the tip 1304, 1404 of the stylets 1302, 1402. The modified stylets 1302, 1402 reduce radial misalignment between the cannula 706 and the stylets 1302, 1402. In some examples, the stylets 1302, 1402 can be combined to further improve the interaction between the cutting surface and the tip 1304, 1404.

[0105] FIG. 13 illustrates an alternative stylet 1302 having a modified tip 1304. The stylet 1302 is modified to accommodate for radial misalignment between the cutting surface (not shown, but could include cutting surfaces 507, 707, 1102, 1202). In some examples, radial misalignment between the cutting surface and the stylet (e.g., stylet 502) can result in the cutting surface cutting a portion of the stylet tip (e.g., tip 504). As shown in FIG. 13, the modified tip 1304 includes a gap 1322 defining a gap height 1324. The gap height 1324 permits a misalignment equal to or less than the gap height 1324 before the cutting surface impacts on the stylet 1302.

[0106] FIG. 14 illustrates another alternative stylet 1402 shown, by way of example, in use with the cannula 706. The stylet 1402 is manufactured to improve radial alignment between the cutting surface 707 and the stylet 1402. As shown in FIG. 14, the stylet 1402 includes a tip 1404, a sampling notch 1405, and a spine 1412. As shown in FIG. 14, the proximal end 1420a of the stylet 1402 defines a longitudinal axis 1422. The stylet 1402 has a predetermined curve bias and the tip 1404 defines an angle 1424 away from the longitudinal axis 1422. As shown in FIG. 14, the angle 1424 is inward, away from the sampling notch 1405.

[0107] Similar to the operation of the biopsy tool 400, the cannula 706 is fired towards the tip 1404. Because of the flexibility of the spine 1412, the cannula 706 brings the tip 1404 back in-line with the longitudinal axis 1422. Specifically, the spine 1412 of the stylet 1402 includes an alignment surface 1430 engaged by a ventral portion 1432 of the cannula 706. Because the cannula 706 is more rigid than the flexible spine 1412, the ventral portion 1432 imparts a radial force on the alignment surface 1430. The radial force urges the stylet 1402 more in-line with longitudinal axis 1422. When the cutting surface 707 arrives at the tip 1404, a dorsal portion 1434 of the cannula 706 is brought into telescopic engagement with the tip 1404. Additionally, because the tip 1404 is brought in-line with the longitudinal axis 1422, the cutting surface 707 is kept from engaging the tip 1404 (e.g., cutting into and lodging into the tip 1404).PATENT APPLICATIONATTY. DOCKET NO.: 33685 / 70328 / PC

[0108] The biopsy tool 400 can be modified to incorporate stylets 1302, 1402. Further, the stylets 1302, 1402 can be incorporated into any of the foregoing stylets 502, 702, 902, 1002. Additionally or alternatively, the benefits of (1 ) the tongue and groove 715, 713 and stop 719 and (2) the alternative cutting surfaces 1102, 1202 can be incorporated into the modified stylets 1302, 1402.

[0109] Variations of cannula shafts of the flexible tissue sampling mechanism

[0110] FIGS. 15-17 illustrate alternative laser cut patterns 1502, 1602, 1702 in a metallic cannula shaft 1504, 1604, 1704, respectively. The modified cannula shafts 1504, 1604, 1704 have adjustable stiffness along a length of the shafts based on the pattern of laser cut slits, allowing for improved control of the kinetic energy profile of the cannula when fired by the drive mechanism (as described above). The laser cut patterns 1502, 1602, 1702 are shown by way of example, and could include combinations or variations of the example laser cut patterns 1502, 1602, 1702. Additionally, the laser cut patterns 1502, 1602, 1702 can change along the length of the cannula 1504, 1604, 1704. As a result, the axial stiffness is adjustable along the length of the cannula shafts 1504, 1604, 1704. In the present example, the laser cut patterns 1502, 1602, 1702 are cut in the cannula shafts 1504, 1604, 1704 using a laser cutter but can be cut into the cannula shafts in any other manner, such as water jet cutter or a mechanical cutting process (e.g., a saw blade).

[0111] The laser cut patterns 1502, 1602, 1702 form living hinges to provide flexibility to allow the cannula to navigate the catheter (e.g., elongate device 408) to the target tissue location, which may be located deep within a patient’s lungs. In some examples, the laser cut patterns 1502, 1602, 1702 may extend to a proximal end of a cutting surface 507 of the cannula 506. However, in other examples, the laser cut patterns 1502, 1602, 1702 may end prior to a proximal end of the cutting surface 507. Examples of biopsy tools including slits are described in U.S. Patent Application No. 2020 / 0077991 , which is incorporated by reference herein in its entirety.

[0112] In FIG. 15, the cannula 1504 includes the laser cut pattern 1502 having a helical pattern of slits 1512. In FIG. 16, the cannula 1604 includes the laser cut pattern 1602 having a first helical pattern of slits 1612, a second helical pattern of slits 1614, and lateral slits 1616. The first and second helical patterns of slits 1612, 1614 counteract any rotational movement of the cannula shaft 1604. Additionally, in FIG. 17, the cannula shaft 1704 includes example lateral slits 1712. In each of the foregoing examples, a higher density of slits 1512, 1612, 1614, 1616,PATENT APPLICATIONATTY. DOCKET NO.: 33685 / 70328 / PC1712 decreases the axial stiffness of the cannula shaft 1504, 1604, 1704, respectively. In some examples, the helical laser cut slits 1512, 1612, 1614 cause the cannula shaft 1504, 1604 to rotate when the cannula shafts 1504, 1604 undergo axial deformation. Alternatively, opposing helical patterns can counteract each other and reduce or inhibit the rotation of the cannula shaft 1604.

[0113] When firing the cannula 1504, 1604, 1704, the slits 1512, 1612, 1614, 1616, 1712 can flex and also act as an axial limiter, limiting the axial movement of the cannula 1504, 1604, 1704 relative to a stylet. The length, density, and configuration of the slits 1512, 1612, 1614, 1616, 1712 can affect the actuation of a cutting surface (e.g., cutting surfaces 507, 707, 1114, 1214). For example, helical slits can cause the cutting surface to rotate. Additionally, the slits 1512, 1612, 1614, 1616, 1712 can flex in the axial direction and, similar to a spring, convert axial kinetic energy of the cannula and the cutting surface to be stored as potential energy in the flexed slits 1512, 1612, 1614, 1616, 1712. By adjusting the length, density, and configuration of the slits 1512, 1612, 1614, 1616, 1712, the energy of profile of the cannula 1504, 1604, 1704 can be better controlled when the cannulas 1504, 1604, 1704 are fired, as described above in connection with biopsy tool 400. As a result, the slits 1512, 1612, 1614, 1616, 1712 reduce the likelihood of the cannula 1504, 1604, 1704 overshooting a stylet.

[0114] In the present example, the length, density, and configuration of the slits 1512, 1612, 1614, 1616, 1712 are adjusted along the length of the cannula shafts 1504, 1604, 1704. The density of the slits 1512, 1612, 1614, 1616, 1712 are lower in a first portion of the cannula shafts 1504, 1604, 1704 and higher in a second portion of the cannula shafts 1504, 1604, 1704. For example, the slits 1512, 1612, 1614, 1616, 1712 are less densely positioned in the first portion adjacent to the handle (e.g., handle 406) and more densely positioned in a second portion at a distal end of the cannula shafts 1504, 1604, 1704 proximate to the cutting surface (e.g., cutting surface 507). As a result, the cannula shafts 1504, 1604, 1704 are more axially flexible proximate to the (e.g., sampling notch 505) and stiffer around the handle.

[0115] The cannula shafts 1504, 1604, 1704 are slit cut hypotubes. The slit cut hypotubes provide a space-efficient, variably stiff shaft for the cannula (e.g., cannula 506, 706). The low wall thickness of the cannula shafts 1504, 1604, 1704 increases the available space for the stylet and sheath to optimize performance and safety.

[0116] Additionally, in various examples, the biopsy tool 400 can be modified to operate using a cannula incorporating laser cut patterns 1502, 1602, 1702. Additionally, the cannulasPATENT APPLICATIONATTY. DOCKET NO.: 33685 / 70328 / PC706 can be modified to incorporate the laser cut patterns 1502, 1602, 1702 and used in combination with any of the aforementioned stylets (e.g., stylets 702, 902, 1002, 1302,1402).

[0117] Variation of the stylet tip of the flexible tissue sampling mechanism

[0118] FIG. 18 illustrates an alternative stylet 1802 configured to reduce the likelihood of overshoot. The alternative stylet 1802 adjusts the configuration of the tip 1804 to provide a longer landing zone the cutting surface 1807 can overshoot a target point 1809 without overshooting the distalmost tip of the tip 1804. The stylet 1802 includes a tip 1804. Similarly, the stylet 1802 is disposed within a cannula shaft 1806 having a cutting surface 1807. In the present example, the cutting surface 1807 is similar to the cutting surface 507 described in connection with FIG. 5, but could by any cutting surface (e.g., the cutting surfaces described in connection with FIGS. 11 and 12). In the present example, the tip 1816 has a tip angle 1816. The length 1814 of the landing zone 1812 is increased by reducing the tip angle 1816.

[0119] Additionally or alternatively, the tip 1804 of the stylet can include a distal body 1820 having an increased length 1822. As shown in FIG. 18, the length 1822 extends from the sample notch (e.g., sample notch 505) to the tip 1804. The length 1822 can be lengthened as needed to provide an appropriate landing zone 1812. In such examples, the distal body 1820 can be modified to ensure the tip 1804 is sufficiently flexible to traverse the tortuous internal channel. In one example, the body 1820 can include slits or a kerf (similar to the kerf 724 described above in connection with FIG. 7A).

[0120] The landing zone 1812 is shown by the length 1814 between the tip 1804 and the cutting surface 1807. In preferred operation of the biopsy tool 400, the cutting surface 1807 stops at a target point on the stylet tip 1804. In the present example, the target point 1822 is disposed at a proximal end of the landing zone. By increasing the length 1814 of the landing zone 1812, the margin of error for the cutting surface 1807 extending beyond the tip 1804 is increased.

[0121] Additionally, in various examples, the biopsy tool 400 can be modified to operate using a stylet 1802 having a longer landing zone, as described above. Additionally, any of the aforementioned stylets (e.g., stylets 702, 902, 1002, 1302,1402) can be modified to include a longer landing zone.

[0122] Variations of the handle of the flexible tissue sampling mechanismPATENT APPLICATIONATTY. DOCKET NO.: 33685 / 70328 / PC

[0123] FIGS. 19, 20, and 21 illustrate alternative handles 1900, 2000, 2100 for the biopsy tool 400. In each of the foregoing examples, the handles 1900, 2000, 2100 are configured to provide an improved cannula energy profile when firing the cannula (e.g., cannula 506). The alternative handle 1900 provides an adjustable drive mechanism while handles 2000, 2100 provide dampers that increase control over the energy profile and reduce oscillations of the cannula (e.g., cannula 506) after firing.

[0124] FIG. 19 shows an example of a handle 1900 that may be used with a biopsy tool described herein. The handle 1900 may be coupled with a proximal end portion of a cannula 1902 that may extend distally out from the handle 1900. The handle 1900 may be controlled manually (e.g., by a physician in a room with a patient undergoing a biopsy procedure), robotically-assisted, or teleoperatively controlled (e.g., by a physician located inside or outside the room). The handle 1900 may include a drive mechanism to generate a drive force. The drive mechanism is operatively coupled to the cannula 1902. In the present example, the drive mechanism is a spring 1904 operatively coupled to the cannula 1902. The cannula and stylet may be biased to a closed configuration as described above. It should be noted that the spring 1904 is a non-limiting example of a drive mechanism, and the cannula and stylet may be biased to either a closed or open configuration using any other appropriate construction. As shown in FIG. 19, the handle 1900 may include a draw handle 1906 that is coupled to either the cannula or stylet such that the cannula or stylet is configured to axially move with the draw handle 1906. For example, the draw handle 1906 may be coupled to the cannula such that when the draw handle is moved in a proximal direction, the cannula moves axially in a proximal direction relative to the stylet to move the biopsy tool to an open configuration and expose a notch in the stylet. Moving the draw handle 1906 in a proximal direction may compress the spring 1904 to load the spring. The draw handle 1906 may be locked in the proximal position to resist the force of the spring and to maintain the biopsy tool in the open configuration by a lock 1908. The lock 1908 is depicted as a button lock that, when depressed, may release the draw handle 1906 from the locked proximal position, allowing spring 1904 to push the draw handle 1906 back to its distal position. As the draw handle is moved distally by the spring, the cannula 1902 is correspondingly moved in the distal direction back to the closed configuration. The force of the spring may cause the cannula 1902 to move with a sufficient force to shear off a portion of the target tissue positioned in the notch of a stylet. While a particular drive mechanism is depicted in FIG. 19, it should be noted that the disclosure is not so limiting, and other drive or firing mechanisms may be used to move the biopsy tool between the disclosed open and closed configurations. In various other examples, the drive mechanism of the biopsy device handlePATENT APPLICATIONATTY. DOCKET NO.: 33685 / 70328 / PC1900 includes spring, a servo, a motor, or a robotic system (as described above in connection with FIG. 3), a pneumatic system, or any other appropriate actuator. In some examples, when the drive mechanism includes a motor, the motor can further operate as an axial limiter mechanism. In such an example, the motor drives the cannula in a firing operation and includes a braking operation to control the velocity profile of the cannula (e.g., cannula 506) along the stroke of the cannula relative to the flexible stylet (e.g., stylet 502).

[0125] In the present example, the drive mechanism is adjustable. As a result, the drive force is also adjustable. The spring 1904 can be loaded with a different amount of energy based on the configuration of the biopsy tool. In some examples, the handle 1900 includes an adjustment mechanism to manually adjust the compressed length of the spring 1904 when the handle 1906 is drawn back in its distal position. The adjustment mechanism can be manually adjusted to control an adjustable stroke length. The stroke length can be calculated based on the desired sample size and location (e.g., tortuosity of the path). In various examples, the adjustment mechanism can be any mechanism to adjust the stroke length of the handle 1900 or spring 1904.

[0126] In some examples, the cannula 1902 includes the shape sensor 222 (described above in connection with FIG. 2) to assess an anatomical tortuosity. The drive mechanism is adjustable to generate a drive force based on the assessed anatomical tortuosity. In some examples, the load of the compressed spring 1904 can be adjusted manually while in other examples, the load is adjusted automatically or robotically through the use of a control system (e.g., control system 112). In some examples, the handle 1900 includes an adjustment mechanism (manual or automated) to adjust the compressed length of the spring 1904 when the handle 1906 is drawn back in its distal position. In various examples, the adjustment mechanism (not shown) can include a screw and fastener, a cam, a lockable rack and pinion, or any other mechanism that can adjust a compressed length of a spring 1904. By adjusting the load of the compressed spring 1904, an operator can control the energy profile of the cutting surface (e.g., cutting surface 507, 707, 1114, 1214) along a stroke of the cannula relative to the stylet. In some examples, controlling the energy profile of the cutting surface limits the likelihood of the cutting surface overshooting the tip of the stylet.

[0127] FIGS. 20 and 21 illustrate alternative handles 2000, 2100 made in accordance with the present disclosure. The handles 2000, 2100 are similar to the handle 1900, described above, and includes cannulas 2002, 2102; springs 2004, 2104; and handles 2006, 2106, respectively. The handles 2000, 2100 includes include axial limiters 2012, 2112, respectively.PATENT APPLICATIONATTY. DOCKET NO.: 33685 / 70328 / PCThe axial limiters 2012, 2112 reduce oscillation of the cannula when fired during operation of the biopsy tool (e.g., biopsy tool 400). As shown in FIGS. 20 and 21 , the axial limiters 2012, 2112 are disposed within the handles 2000, 2100, respectively. In other examples, the axial limiters are disposed on the handles 2000, 2100.

[0128] In FIG. 20, the axial limiter 2012 is a damper, such as a shock absorber 2014. The shock absorber 2014 is a pneumatic shock absorber and operates similar to known shock absorbers. The shock absorber 2014 generally includes a piston, pressure chamber, return spring, and outer body. The piston acts on the pressure chamber to convert the kinetic energy of the piston into pressure energy that is dissipated as the air passes from the pressure chamber to the outer body. The shock absorber 2014 is in-line with the cannula 2002, but in other examples, could be disposed adjacent to the cannula 2002. In various other examples, the shock absorber 2014 could be a hydraulic shock absorber, friction shock absorber, twin tube shock absorber, or any other suitable shock absorber.

[0129] In FIG. 21 , the axial limiter 21 12 is a damper such as a viscoelastic material 2114. In the present example, the viscoelastic material 21 14 is a polyurethane polymer. The cannula 2102 engages the viscoelastic material 2114 via a shoulder (not shown) disposed on the cannula 2102. In various examples, the viscoelastic material 2114 can include any material that has viscoelastic properties, such as, low durometer thermoplastic polyurethane, styrenic block copolymers, silicone rubber, butyl rubber, nitrile rubber, ethylene propylene diene monomer (EPDM), and polychloroprene.

[0130] Additionally, in various examples, the biopsy tool 400 can be modified to operate using the handles 1900, 2000, 2100. Additionally, the handles 1900, 2000, 2100 can be modified to operate with any of the stylets 502, 702, 902, 1002, 1302, 1402, 1802; any of the cannulas 506, 706, 1504, 1604, 1704, 1806; and / or any of the cutting surfaces 507, 707, 1102, 1202, 1807.

[0131] The biopsy tool 400, as described herein, provides several benefits over other biopsy tools. The various improvements to the stylet 702, 902, 1302, 1402; cannula 706, 1504, 1604, 1704, cutting surface 707, 11 14, 1214; and handle 1900, 2000, 2100 improve the biopsy sample quality while improving the functionality of the biopsy tool.

[0132] First, several of the variations reduce the likelihood of the cutting surface extending beyond the tip of the stylet. For example, modifying the stylet and cannula to have a tongue and groove with an integrated stop; increasing the landing zone of the stylet tip,PATENT APPLICATIONATTY. DOCKET NO.: 33685 / 70328 / PC adjusting the load on a spring in the handle, and adjusting the stiffness of the cannula shaft each improve the functionality of the biopsy tool. In various examples, the biopsy tool can utilize any one of the foregoing to reduce the likelihood of the cutting surface extending beyond the stylet tip. Alternatively, a combination of two or more of the foregoing can be combined to provide the same or better benefit.

[0133] Second, several of the variations maintain rotational alignment of the cutting surface and the sampling notch of the style or permit the biopsy tool to operate without the need to align a cutting surface and the sampling notch. For example, replacing a cutting surface with a circumferential cutting surface or upgrading the stylet to have a center spine allows an operator to more easily operate the biopsy tool without concern for aligning the cutting surface and the sampling notch. Alternatively, incorporating a tongue and groove on the stylet and cannula can ensure the cutting surface and sampling notch remain aligned. In various examples, the biopsy tool can utilize any one of the foregoing to maintain rotational alignment of the cutting surface and the sampling notch. Alternatively, a combination of two or more of the foregoing can be combined to provide the same or better benefit.

[0134] Third, several of the discussed variations maintain radial alignment between the cutting surface and the stylet tip to reduce interference between the cutting surface and the stylet tip. The stylet tip can be modified to bend away from the sampling notch to ensure the cannula brings the stylet into alignment as the cannula fires. Additionally, the stylet tip includes a gap height that provides a margin of error to reduce interference between the cutting surface and the stylet tip.

[0135] Those skilled in the art will recognize that a wide variety of modifications, alterations, and combinations can be made with respect to the above described examples without departing from the spirit and scope of the invention(s) disclosed herein, and that such modifications, alterations, and combinations are to be viewed as being within the ambit of the inventive concept(s).

Claims

PATENT APPLICATIONATTY. DOCKET NO.: 33685 / 70328 / PCCLAIMSWhat is claimed is:1 . A medical system, comprising: a flexible tissue sampling mechanism including a cannula and a stylet disposed within the cannula; at least one sensor configured to generate sensor data indicating a shape of the flexible tissue sampling mechanism; and a drive mechanism configured to generate a drive force that varies based on the sensor data to advance the cannula relative to the stylet to take a tissue sample.

2. The system of claim 1 , further comprising a flexible elongate device including the at least one sensor, wherein the flexible elongate device includes a channel through which the flexible tissue sampling mechanism is inserted and flexible tissue sampling mechanism conforms to shape of the channel.

3. The system of claim 2, wherein the flexible tissue sampling mechanism is movable within the channel relative to the flexible elongate device.

4. The system of any one of claims 1 to 3, wherein the flexible tissue sampling mechanism includes the at least one sensor.

5. The system of any one of claims 1 to 4, wherein the drive mechanism includes spring, motor, or pneumatic actuator.6 The system of claim 5, wherein the drive mechanism is operably coupled to the cannula of the tissue sampling mechanism.

7. The system of any one of claims 1 to 6, further comprising a control system configured to: receive the sensor data from the at least one sensor; and operate the drive mechanism to generate the drive force based on the sensor data.PATENT APPLICATIONATTY. DOCKET NO.: 33685 / 70328 / PC8. The system of claim 7, wherein the control system is configured to determine, based on the sensor data, the drive force that results in a target velocity of the cannula relative to the stylet.

9. The system of claim 7, wherein the drive force generated by the drive mechanism adjusted based on the sensor data.

10. The system of any one of claims 1 to 9, wherein the drive force is manually adjusted.11 . The system of claim 10, wherein the control system is configured to provide an indication that varies based on the sensor data to a user for the manual adjustment.

12. The system of any one of claims 1 to 11 , wherein the drive force is automatically adjusted.

13. The system of claim 12, wherein adjustment of the drive force includes setting a force profile of the drive force along a stroke of the cannula relative to the stylet.

14. The system of any one of claims 1 to 13, wherein the control system calculates a bend angle of the flexible tissue sampling mechanism based on the sensor data; and determines the drive force based on the bend angle.

15. The system of claim 14, wherein the control system determines an accumulated curvature of the flexible tissue sampling mechanism; and determines the drive force based on the accumulated curvature.

16. The system of any one of claims 14 to 15, wherein the control system: calculates a bend angle of the flexible elongate device based on the sensor data; and determines the drive force based on the bend angle.

17. The system of any one of claims 1 to 16, wherein the at least one sensor comprises a shape sensor.PATENT APPLICATIONATTY. DOCKET NO.: 33685 / 70328 / PC18. The system of claim 17, wherein the at least one sensor comprises a plurality of position sensors positioned at different locations.

19. The system of any one of claims 2 to 18, wherein the sensor is carried by the flexible elongate device and / or tissue sampling mechanism.

20. The system of any one of claims 2 to 19, wherein the flexible elongate device includes a catheter or endoscope.21 . The system of any one of claims 1 to 20, wherein the tissue sampling mechanism further comprises a sheath at least partly surrounding the cannula and stylet.

22. The system of claim 21 , wherein the sheath includes a sheath cap.

23. A medical system, comprising: a flexible tissue sampling mechanism including: a cannula including a cutting surface and a channel; and a stylet including a tissue sampling notch, the stylet being at least partially disposed in the channel such that the stylet and the cannula are moveable relative to each other; and a first alignment surface disposed on one of the cannula and the stylet; and a second alignment surface disposed on the other one of the cannula and the stylet, the first alignment surface and the second alignment surface in physical contact with each other such that the cannula and the stylet are limited in rotational movement relative to each other.

24. The system of claim 23, wherein the first alignment surface comprises a tongue and the second alignment surface comprises a groove configured to slidably receive the tongue.

25. The system of claim 24, wherein the tongue and groove have a T-shaped cross section.

26. The system of claim 24, wherein the tongue engages a hard stop disposed at an end of the groove.PATENT APPLICATIONATTY. DOCKET NO.: 33685 / 70328 / PC27. The system of any one of claims 23 to 26, wherein the first alignment surface comprises a non-circular exterior surface and the second surface comprises a nesting, complementary non-circular exterior surface.

28. The system of claim 27, wherein a cross-sectional shape of the first alignment surface is ovular.

29. The system of any one of claims 23 to 28, wherein the first and second alignment surfaces radially align a cannula tip and a stylet tip relative to a central longitudinal axis.

30. The system of claim 29, wherein the stylet includes a predetermined curve bias.31 . The system of claim 30, wherein the predetermined curve bends the stylet inward, away from the tissue sampling notch.

32. The system of any one of claims 23 to 31 , further comprising a sheath defining a second channel.

33. The system of claim 32, wherein the sheath includes a sheath cap disposed on a distal end of the sheath.

34. The system of claim 33, wherein the sheath cap is made of metal.

35. The system of claim 32, wherein at least one of the sheath, cannula, and or stylet are made from or lined with a low-friction material such as a fluoropolymer, Polytetrafluoroethylene (PTFE), stainless steel, parylene.

36. The system of any one of claims 23 to 35, wherein the cannula includes a laser cut cannula shaft including a first portion having a first density of laser cuttings and a second portion having a second density of laser cuttings, the first density different than the second density.

37. The system of any one of claims 23 to 36, wherein the second portion is disposed on a distal portion of the cannula shaft and the second density is less than the first density.PATENT APPLICATIONATTY. DOCKET NO.: 33685 / 70328 / PC38. A medical system, comprising: a flexible tissue sampling mechanism including: a flexible cannula including a cannula shaft and a cutting surface distal to the flexible cannula shaft, the cannula defining a channel; and a flexible stylet including a stylet shaft and a stylet tip distal to the stylet shaft, the stylet shaft at least partially disposed in the channel, wherein the stylet and the cannula are moveable relative to each other to take a tissue sample; and a cannula control including: a drive mechanism operably coupled to the cannula shaft; and an axial limiter mechanism that, during relative movement of the stylet and cannula to take a tissue sample, limits extension of the cutting surface beyond a target point proximal to a distal end of the stylet tip.

39. The system of claim 38, wherein the axial limiter includes a damper.

40. The system of claim 39, wherein the damper includes a shock absorber.41 . The system of claim 39, wherein the damper includes a viscoelastic material.

42. The system of claim 39, wherein the damper is disposed within or on a handle of the medical system.

43. The system of any one of claims 38 to 42, wherein the axial limiter includes a tongue and groove.

44. The system of claim 43, wherein the tongue engages an end stop of the groove.

45. The system of claim 43, wherein the tongue is disposed on one of the cannula and the stylet and the groove is disposed on the other of the cannula and the stylet.

46. The system of any one of claims 38 to 45, wherein the axial limiter includes a laser cut cannula shaft to axially stiffen a distal portion of the cannula shaft.PATENT APPLICATIONATTY. DOCKET NO.: 33685 / 70328 / PCM. The system of claim 46, wherein the cannula shaft includes a first portion having a first density of laser cuttings and a second portion having a second density of laser cuttings, the first density different than the second density.

48. The system of claim 47, wherein the second portion is disposed on the distal portion of the cannula shaft and the second density is less than the first density.

49. The system of any one of claims 38 to 48, wherein the axial limiter mechanism comprises an electrical motor.

50. The system of claim 49, wherein the motor controls cannula deceleration.51 . The system of claim 49, wherein the motor is disposed within or on a handle of the medical system.

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