CN220158353U

CN220158353U - Magnetic tracking stylet

Info

Publication number: CN220158353U
Application number: CN202221089487.1U
Authority: CN
Inventors: M·戴维斯; B·E·拉基; E·D·贝尔; R·S·厄里; D·B·布兰查德; S·R·艾萨克森; B·J·范德斯特克; T·M·埃利; A·拉森; H·N·德兰
Original assignee: Bard Access Systems Inc
Current assignee: Bard Access Systems Inc
Priority date: 2021-04-28
Filing date: 2022-04-27
Publication date: 2023-12-12
Anticipated expiration: 2032-04-27

Abstract

The present application relates to a magnetically trackable stylet. The magnetically trackable stylet can include a stylet body including a core wire, a magnetic assembly, and an external configuration over the core wire and the magnetic assembly. The magnetic assembly may include one or more magnetic field generating elements disposed in the magnetically trackable distal portion of the stylet body alongside the core wire. The outer construction may be an over-molded layer, a reflow layer, an potting layer, or a shrink wrap layer, which may surround the core wire and the magnetic assembly. The stylet body may be configured to be disposed in a lumen of a medical device, such as a catheter, for magnetically tracking the tip of the medical device in vivo without fracturing the stylet body due to bending-related fatigue.

Description

Magnetic tracking stylet

Priority

The present application claims priority from U.S. provisional patent application No. 63/181,060 filed on day 28 of month 2021 and U.S. provisional patent application No. 63/181,071 filed on day 28 of month 2021, each of which is incorporated herein by reference in its entirety.

Technical Field

The present application relates to the field of medical devices, and more particularly to magnetically trackable stylet.

Background

Sherlock 3CG ^TM The tip verification system and the shalock 3cg+tcs (collectively "TCS") are used for the guidance and positioning of peripherally inserted central catheters ("PICCs"). The TCS uses passive magnet tracking and electrocardiographic activity of each patient, providing such guidance and localization with real-time positional information of the PICC tip. Thus, for placement of PICC in adult patients, TCS is chest X-rayAnd an advantageous alternative to fluoroscopy, especially when relying on electrocardiogram ("ECG") signals of the patient. Since the use of TCS can increase the positioning speed of PICCs by a factor of 5 while reducing misalignment and reducing X-ray exposure, TCS is still important for guiding and positioning PICCs.

Disclosed herein are magnetically trackable stylet and methods thereof for TCS or other such systems for medical device placement that utilize at least magnetic tracking to place medical devices.

Disclosure of Invention

Disclosed herein is a magnetically trackable stylet that, in some embodiments, includes a stylet body including a core wire, a flexible magnetic component, and a cannula (stiffening). The magnetic assembly includes one or more magnetic field generating elements disposed in the magnetically trackable distal portion of the stylet body alongside the core wire. The sleeve surrounds the core wire and the magnetic assembly. The stylet is configured to be disposed in the lumen of the catheter for magnetically tracking the catheter tip in vivo without fracturing the stylet due to bending-related fatigue.

In some embodiments, the core wire tapers in the distal portion of the stylet body alongside the one or more magnetic field generating elements.

In some embodiments, the stylet further comprises a sealed stylet tip. The stylet tip includes a seal that seals the one or more magnetic field generating elements in the distal portion of the stylet body.

In some embodiments, the one or more magnetic field generating elements comprise one or more polymer bonded magnets. The one or more polymer bonded magnets are configured to bend and thereby allow the stylet to bend according to the anatomy of the patient without breaking.

In some embodiments, the one or more polymer bonded magnets comprise a single cylindrical polymer bonded magnet.

In some embodiments, the one or more polymer bonded magnets comprise a plurality of cylindrical polymer bonded magnets.

In some embodiments, the one or more magnetic field generating elements comprise one or more sintered magnets.

In some embodiments, the one or more sintered magnets include a plurality of cylindrical sintered magnets having rounded ends (rounded ends). The rounded ends of the cylindrical magnets are configured to allow the cylindrical magnets to bend toward each other and thereby allow the stylet to bend according to the anatomy of the patient without breaking.

In some embodiments, the one or more sintered magnets comprise a plurality of cylindrical sintered magnets alternating with a plurality of spherical sintered magnets. Alternating cylindrical and spherical magnets form an articulatable joint therebetween. The connector is configured to allow the cylindrical magnets to bend toward each other and thereby allow the stylet to bend according to the anatomy of the patient without breaking.

In some embodiments, the one or more sintered magnets comprise a plurality of cylindrical sintered magnets alternating with a plurality of nonmetallic spheres. Alternating cylindrical magnets and nonmetallic spheres form an articulatable joint therebetween. The connector is configured to allow the cylindrical magnets to bend toward each other and thereby allow the stylet to bend according to the anatomy of the patient without breaking.

In some embodiments, the one or more sintered magnets include a plurality of cylindrical sintered magnets alternating with a plurality of spacers that segment grooves of a magnet holder in which the sintered magnets are disposed. The spacer forms an articulatable joint between the cylindrical magnets. The connector is configured to allow the cylindrical magnets to bend toward each other and thereby allow the stylet to bend according to the anatomy of the patient without breaking.

In some embodiments, the one or more sintered magnets comprise a plurality of cylindrical sintered magnets disposed in a plurality of magnet holders to form an articulatable joint therebetween. The connector is configured to allow the cylindrical magnets to bend toward each other and thereby allow the stylet to bend according to the anatomy of the patient without breaking.

In some embodiments, each of the magnet holders includes a ball end (ball end) and a socket end (socket end). The joint between the magnet holders is a ball-and-socket joint.

In some embodiments, the magnet holder includes a ball end magnet holder having a pair of ball ends and a socket end magnet holder having a pair of socket ends. The joint between the magnet holders is a ball joint.

In some embodiments, the magnet holder is a link and the joint is an interconnect between links that are linked together.

In some embodiments, the one or more magnetic field generating elements comprise one or more magnet wires stranded or braided with the core wire. The one or more magnet wires are configured to bend and thereby allow the stylet to bend according to the anatomy of the patient without breaking.

Disclosed herein is a magnetically trackable stylet that, in some embodiments, includes a stylet body including a flexible magnetic assembly and a cannula. The magnetic assembly includes one or more magnet wires in a magnetically trackable distal portion of the stylet body. The sleeve surrounds the magnetic assembly. The stylet is configured to be disposed in the lumen of the catheter for magnetically tracking the catheter tip in vivo without fracturing the stylet due to bending-related fatigue.

In some embodiments, the one or more magnet wires comprise a single magnet wire.

In some embodiments, the stylet further comprises a core wire. The magnet wire is stranded with the core wire in the distal portion of the stylet body.

In some embodiments, the stylet further comprises a core wire. The magnetic wire is helically wrapped around the core wire in the distal portion of the stylet body.

In some embodiments, the one or more magnet wires comprise a plurality of magnet wires.

In some embodiments, the stylet further comprises a core wire. The magnetic wire is stranded or braided with the core wire in the distal portion of the stylet body.

In some embodiments, the stylet further comprises a core wire. The magnetic wire is stranded or braided around the core wire in the distal portion of the stylet body.

In some embodiments, the stylet further comprises a sealed stylet tip. The stylet tip includes a seal that seals the magnet wire in the distal portion of the stylet body.

Disclosed herein is a magnetically trackable stylet that, in some embodiments, includes a stylet body including a core wire, a magnetic assembly, and an external configuration over the core wire and the magnetic assembly. The magnetic assembly includes one or more magnetic field generating elements disposed in the magnetically trackable distal portion of the stylet body alongside the core wire. The outer construction is selected from the group consisting of an over-molded layer (overmolded layer), a reflow layer (reflowed layer), a potting layer (potting layer), and a shrink-wrapped layer (shrnk-wrapped layer). The stylet is configured to be disposed in the lumen of the catheter for magnetically tracking the catheter tip in vivo without fracturing the stylet due to bending-related fatigue.

In some embodiments, the external construct is a single layer external construct.

In some embodiments, the external construct comprises an overmolded layer. An overmolded layer is molded around the core wire and the magnetic assembly.

In some embodiments, the one or more gaps between any two or more magnetic field generating elements comprise a polymeric material of an overmolded layer therebetween. One or more gaps having a polymeric material form one or more hingeable joints in the magnetic assembly.

In some embodiments, the external construct includes a reflow layer. The reflow layer reflows around the core wire and the magnetic assembly.

In some embodiments, the one or more gaps between any two or more magnetic field generating elements comprise a polymeric material of the reflow layer therebetween. One or more gaps having a polymeric material form one or more hingeable joints in the magnetic assembly.

In some embodiments, the external construct comprises an encapsulating layer. The potting layer encapsulates the core wire and the magnetic assembly.

In some embodiments, the one or more gaps between any two or more magnetic field generating elements comprise potting material of the potting layer therebetween. One or more gaps with potting material form one or more hingeable joints in the magnetic assembly.

In some embodiments, the outer construction comprises a shrink wrap layer. The shrink wrap layer shrinks around the core wire and the magnetic assembly.

In some embodiments, one or more gaps between any two or more magnetic field generating elements form one or more articulatable joints in the magnetic assembly.

In some embodiments, the external construct is a multi-layer external construct.

In some embodiments, the external construct includes an overmolded layer and one or more other layers on the overmolded layer. An overmolded layer is molded around the core wire and the magnetic assembly.

In some embodiments, one or more other layers include a sleeve disposed over the overmolded layer.

In some embodiments, the external construction includes a reflow layer and one or more other layers on the reflow layer. The reflow layer reflows around the core wire and the magnetic assembly.

In some embodiments, the one or more other layers include a braid over the reflow layer and an outer sleeve over the braid. The reflow layer reflows into the braid.

In some embodiments, the external construct includes an potting layer and one or more other layers on the potting layer. The potting layer encapsulates the core wire and the magnetic assembly.

In some embodiments, the one or more other layers include a sleeve disposed over the potting layer.

In some embodiments, the outer construction includes a shrink wrap layer and one or more other layers on the shrink wrap layer. The shrink wrap layer shrinks around the core wire and the magnetic assembly.

In some embodiments, the one or more other layers include a sleeve disposed on the shrink wrap layer.

These and other features of the concepts provided herein will become more readily apparent to those skilled in the art in view of the drawings and the following description, which describe in more detail certain embodiments of the concepts.

Drawings

Fig. 1 illustrates a block diagram depicting various elements of a first integrated system for placement of a medical device, such as a catheter, within a patient, in accordance with some embodiments.

Fig. 2 illustrates a simplified view of a patient and a catheter placed within the patient using a first integrated system according to some embodiments.

Fig. 3 illustrates an ultrasound image on a display of a first integrated system according to some embodiments.

Fig. 4 illustrates a perspective view of a first stylet of the first integrated system, according to some embodiments.

Fig. 5A illustrates a graphical representation on a display of a first integrated system while the catheter is placed but before the tip position sensor receives a signal, according to some embodiments.

Fig. 5B illustrates a graphical representation on a display of the first integrated system with signals received at the perimeter of the tip position sensor, according to some embodiments.

Fig. 5C illustrates a graphical representation on a display of the first integrated system with signals received under the tip position sensor, according to some embodiments.

Fig. 6 illustrates a block diagram depicting various elements of a second integrated system for placement of a medical device, such as a catheter, within a patient, in accordance with some embodiments.

Fig. 7 illustrates a simplified view of a patient and a catheter placed within the patient using a second integrated system according to some embodiments.

Fig. 8 illustrates a perspective view of a second stylet of the second integrated system, according to some embodiments.

Fig. 9 illustrates a simplified view of a patient's ECG trace according to some embodiments.

Fig. 10 illustrates a graphical representation on a display of a second integrated system in the event that a signal is received beneath a tip position sensor, according to some embodiments.

Fig. 11 illustrates a stylet body of the first or second stylet according to some embodiments.

Fig. 12 illustrates a detailed cross-sectional view of a distal portion of a first or second stylet according to some embodiments.

Fig. 13 illustrates a detailed cross-sectional view of a distal portion of a first or second stylet according to some embodiments.

Fig. 14 illustrates a detailed cross-sectional view of a distal portion of a first or second stylet according to some embodiments.

Fig. 15A illustrates a detailed cross-sectional view of a distal portion of a first or second stylet according to some embodiments.

Fig. 15B illustrates a detailed cross-sectional view of the distal portion of the stylet of fig. 15A rotated 90 ° along the axis of the stylet, in accordance with some embodiments.

Fig. 16 illustrates a detailed cross-sectional view of a distal portion of a first or second stylet according to some embodiments.

Fig. 17 illustrates a detailed cross-sectional view of a distal portion of a first or second stylet according to some embodiments.

Fig. 18 illustrates a detailed cross-sectional view of a distal portion of a first or second stylet according to some embodiments.

Fig. 19 illustrates a detailed cross-sectional view of a distal portion of a first or second stylet according to some embodiments.

Fig. 20A illustrates a detailed cross-sectional view of a distal portion of a first or second stylet including a first external configuration, according to some embodiments.

Fig. 20B illustrates a detailed cross-sectional view of a distal portion of a first or second stylet including a second external configuration, in accordance with some embodiments.

Fig. 20C illustrates a detailed cross-sectional view of a distal portion of a first or second stylet including a third external configuration, in accordance with some embodiments.

Fig. 21A illustrates a detailed cross-sectional view of a distal portion of a first or second stylet including a fourth external configuration, in accordance with some embodiments.

Fig. 21B illustrates a detailed cross-sectional view of a distal portion of a first or second stylet including a fifth external configuration, according to some embodiments.

Detailed Description

Before some specific embodiments are disclosed in greater detail, it is to be understood that the specific embodiments disclosed herein are not limiting the scope of the concepts provided herein. It should also be understood that certain embodiments disclosed herein may have features that may be readily separated from the particular embodiments and optionally combined with or substituted for features of any of the many other embodiments disclosed herein.

With respect to the terms used herein, it should also be understood that these terms are for the purpose of describing some particular embodiments and that these terms do not limit the scope of the concepts provided herein. Ordinal numbers (e.g., first, second, third, etc.) are generally used to distinguish or identify a set of features or different features or steps of a set of steps and do not provide a sequence or numerical limitation. For example, the "first," "second," and "third" features or steps need not occur in this order, and particular implementations including such features or steps need not be limited to the three features or steps. Furthermore, any of the foregoing features or steps may in turn comprise one or more features or steps, unless otherwise indicated. Labels such as "left", "right", "top", "bottom", "front", "rear", etc. are used for convenience and are not intended to imply any particular fixed position, orientation or direction, for example. Rather, such labels are used to reflect, for example, relative position, orientation, or direction. The singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise.

For example, reference to "proximal", "proximal portion" or "proximal portion" of a catheter includes a portion of the catheter that is intended to be close to a clinician when the catheter is used on a patient. Likewise, for example, the "proximal length" of the catheter includes a length of the catheter that is intended to be close to the clinician when the catheter is used on a patient. For example, the "proximal end" of the catheter includes the end of the catheter that is intended to be close to the clinician when the catheter is used on a patient. The proximal portion, or proximal length of the catheter may include the proximal end of the catheter; however, the proximal portion, or proximal length of the catheter need not include the proximal end of the catheter. That is, unless the context indicates otherwise, the proximal portion, or proximal length of the catheter is not the tip portion or tip length of the catheter.

For example, reference to "distal", "distal portion" or "distal portion" of a catheter includes a portion of the catheter that is intended to be near or within a patient when the catheter is used on the patient. Likewise, for example, the "distal length" of a catheter includes a length of the catheter that is intended to be near or within a patient when the catheter is used on the patient. For example, the "distal end" of a catheter includes an end of the catheter that is intended to be near or within a patient when the catheter is used on the patient. The distal portion, or distal length of the catheter may include the distal end of the catheter; however, the distal portion, or distal length of the catheter need not include the distal end of the catheter. That is, unless the context indicates otherwise, the distal portion, or distal length of the catheter is not the tip portion or tip length of the catheter.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art.

As described above, TCS continues to be an advantageous alternative to chest X-ray and fluoroscopy for placement of PICCs in adult patients, especially when relying on electrocardiogram ("ECG") signals of the patient. Disclosed herein are magnetically trackable stylet and methods thereof for TCS or other such systems for medical device placement that utilize at least magnetic tracking to place medical devices.

The figures depict features of various embodiments of an integrated system for placement of a medical device, such as a catheter, within a patient's vasculature. In some embodiments, the integrated system employs at least two modes to improve the accuracy of medical device placement: 1) An ultrasound ("US") mode for introducing a medical device (e.g., catheter 72) into the vasculature of a patient under US visualization; 2) A tip position sensor ("TLS") mode for TLS or magnetic tracking of the tip of a medical device (e.g., distal tip 76A of catheter 72) during advancement thereof through tortuous vasculature, which in turn allows for detection and correction of any misalignment of the medical device during such advancement. In some embodiments, the US visualization and TLS tracking of the integrated system are integrated into a single integrated device for use by a clinician placing a medical device. Integrating the features of both modes into an integrated device simplifies and makes placement of the medical device relatively faster. For example, the integrated system enables US guidance and TLS tracking to be viewed from a single display of the integrated system. Moreover, controls located on the US probe of the integrated device (which remains within the sterile field of the patient during placement of the medical device) may be used to control the functions of the integrated system, thereby obviating the need for the clinician to extend beyond the sterile field to control the integrated system.

In some embodiments, a third mode (i.e., ECG mode) is included in the integrated system to enable ECG confirmation of the desired location of the tip of the medical device relative to the junction of the patient's heart that sent the ECG signal.

The combination of the features of the three modes described above enables the integrated system to facilitate placement of the medical device within the vasculature of a patient with a relatively high level of accuracy. Furthermore, due to the ECG confirmation of the tip of the medical device, correct tip placement can be confirmed without the need for confirmatory X-rays. This in turn reduces exposure of the patient to potentially harmful X-rays, reduces the costs and time involved in transporting the patient to and from the X-ray department, reduces expensive and inconvenient repositioning procedures, etc.

Referring first to fig. 1 and 2, various components of an integrated system 10 for placement of a medical device, such as a catheter 72 thereof, are depicted. As shown, the integrated system 10 generally includes a console 20, a display 30, a probe 40, and TLS 50, each of which are described in further detail below, respectively.

Fig. 2 illustrates the general relationship of various components to a patient 70 during a procedure for placing a catheter 72 (e.g., a PICC, a central venous catheter [ "CVC" ] or other suitable catheter) into the vasculature of a patient through an insertion site 73 in the patient's skin. Fig. 2 shows that catheter 72 generally includes a proximal portion 74 that remains outside of patient 70 and a distal portion 76 that resides within the patient's vasculature after placement is complete. The integrated system 10 is used to ultimately position the distal tip 76A of the catheter 72 at a desired location within the vasculature of a patient. In some embodiments, the desired location of the distal tip 76A of the catheter 72 is proximate to the heart of the patient, such as in the lower third of the superior vena cava ("SVC"). However, the integrated system 10 may be used to place the distal tip 76A of the catheter 72 at other locations as desired. The proximal portion 74 of the catheter 72 also includes a hub 74A that provides fluid communication between one or more lumens of the catheter tubing 71 and one or more extension legs 74B extending proximally from the hub 74A.

An example implementation of console 20 is shown in fig. 5C, but it should be understood that console 20 may take any of a variety of forms. As shown in fig. 1, a processor 22 including a non-volatile memory, such as an electrically erasable programmable read-only memory ("EEPROM"), may be included in the console 20 for controlling system functions during operation of the integrated system 10, thereby acting as a control processor. The console 20 also includes a digital controller/analog interface 24. Digital controller/analog interface 24 communicates with processor 22 and other system components to manage interfacing between probes 40, TLS 50 and other system components.

The integrated system 10 also includes optional components 54 including a printer, storage media, keyboard, etc., and ports 52 for connection to the TLS 50. In some embodiments, port 52 is a USB port; however, other port types or combinations of port types may be used for this and other interfacing described herein. A power connection 56 is included in console 20 to enable operative connection with an external power source 58. An internal power source 60 (e.g., a battery) may also be employed, with or without the external power source 58. Power management circuitry 59 is included in digital controller/analog interface 24 of console 20 to regulate power usage and distribution.

The display 30 may be integrated into the console 20. The display 30 is used to display information to the clinician during the placement procedure. In some embodiments, the display 30 may be separate from the console 20. The content depicted by the display 30 varies depending on the mode(s) used on the integrated system 10 (e.g., US mode, TLS mode, ECG mode, or a combination thereof). In some embodiments, console button interface 32 (see fig. 1 and 5C) and buttons included on probe 40 may be used by the clinician to immediately invoke the desired mode to display 30 to aid in the placement procedure. In some embodiments, information from multiple modes, such as TLS and ECG modes, may be displayed simultaneously. (see fig. 10.) thus, the display 30 of the console 20 may be used for US visualization to access the vasculature of the patient, TLS tracking during advancement of the catheter 72 through the vasculature, and ECG confirmation to confirm placement of the distal tip 76A of the catheter 72 relative to the knots of the patient's heart. In some implementations, the display 30 is an LCD device.

The probe 40 shown in fig. 2 is used in conjunction with a first mode (i.e., US mode) for US visualization of a blood vessel, such as a vein, in preparation for insertion of the catheter 72 into the vasculature. Such visualization gives real-time assistance for introducing the catheter 72 into the vasculature of the patient 70 and helps reduce complications commonly associated with such introduction, including inadvertent arterial puncture, hematoma, pneumothorax, and the like.

The probe 40 includes a head housing a piezoelectric array for generating ultrasonic pulses when the head is placed against the patient's skin proximate to the intended insertion site (see fig. 2) and receiving echoes thereof after reflection by the patient's body. The probe 40 also includes a plurality of control buttons that may be included on a button pad as shown in fig. 2. The mode of the integrated system 10 may be controlled by control buttons, thereby eliminating the need for the clinician to extend the sterile field established around the insertion site 73 prior to placement of the catheter 72 to change modes via use of the console button interface 32.

Thus, in some embodiments, the clinician employs a first modality (i.e., US modality) to determine an appropriate insertion site for establishing vascular access, first using a needle or introducer, and then using catheter 72. The clinician may then seamlessly switch to the second mode (i.e., TLS mode) by pressing the control buttons on the control button pad of the probe 40 without having to extend the sterile field. The TLS mode may then be used to help advance the catheter 72 through the vasculature toward the intended destination.

Fig. 1 shows that the probe 40 also includes buttons and a memory controller 42 for managing control buttons and probe operation. In some implementations, the button and memory controller 42 may include a non-volatile memory such as an EEPROM. The button and memory controller 42 is in operative communication with a probe interface 44 of the console 20, which includes a piezoelectric input/output component 44A for interfacing with the probe piezoelectric array and a button and memory input/output component 44B for interfacing with the button and memory controller 42.

Fig. 3 shows an example screen shot 88 depicted on the display 30 when the integrated system 10 is in its first mode (i.e., US mode). An image 90 of a subcutaneous region of the patient 70 is shown depicting a cross section of a vein 92. An image 90 is generated by operation of the piezoelectric array of probe 40. Also included on screen shot 88 are: a depth scale indicator 94 that provides information regarding the depth of the image 90 beneath the patient's skin; a lumen size scale 96 that provides information about the size of the vein 92 relative to a standard catheter lumen size; and other indicia 98 that provide information about the status of the integrated system 10 or actions that may be taken with the integrated system 10 (e.g., frozen frames, image templates, data stores, image printing, power status, image brightness, etc.).

Note that although veins 92 are depicted in image 90, other body cavities or portions may be imaged in other embodiments. Note that the US mode shown in fig. 3 may be depicted on the display 30 simultaneously with other modes (such as TLS mode), if desired. In addition to display 30, integrated system 10 may also employ audible information such as beeps, ringtones, etc. to assist the clinician during placement of catheter 72. In addition, the console button interface 32 and control buttons included on the probe 40 may be configured in a variety of ways for user or clinician input. In practice, slide switches, toggle switches, electronic or touch sensitive pads, etc. may be implemented for user or clinician input. Furthermore, both US visualization and TLS tracking may occur simultaneously or exclusively during use of the integrated system 10.

The stylet 40 may be used as part of the integrated system 10 to enable US visualization of the peripheral vasculature of the patient 70 in preparation for percutaneous introduction of the catheter 72. However, the stylet 40 can also be used to control the functionality of the TLS mode of the integrated system 10 when directing the catheter 72 toward its desired destination within the vasculature. Again, this feature enables TLS tracking to be controlled entirely from within the sterile field of the patient 70, since the probe 40 is used within the sterile field. Thus, the probe 40 is a dual-purpose device that enables convenient control of US visualization and TLS tracking of the integrated system 10 from the sterile field. In some embodiments, the probe 40 may also be used to control some or all ECG related functions for the third mode of the integrated system 10.

The integrated system 10 also includes a second mode, namely, TLS mode. TLS 50 enables a clinician to quickly locate and confirm the position and/or orientation of catheter 72 during initial placement into and advancement through the vasculature of patient 70. Specifically, the TLS mode detects the magnetic field generated by the magnetic field generating tip of the stylet 100, which in some embodiments is preloaded into a longitudinally defined lumen of the catheter 72, thereby enabling the clinician to determine the approximate position and orientation of the distal tip 76A of the catheter within the patient for tracking. In some embodiments, the teachings of one or more of U.S.5,775,322, U.S.5,879,297, U.S.6,129,668, U.S.6,216,028, and U.S.6,263,230, each of which is incorporated herein by reference in its entirety, may be used to track the magnetic field generating tip of stylet 100. TLS 50 also enables display of the direction in which distal tip 76A of catheter 72 is pointed, thereby further aiding in accurate placement of catheter 72. The TLS 50 further assists the clinician in determining when the distal tip 76A of the catheter 72 is misaligned, for example, in the event that the distal tip 76A has deviated from the desired venous path to another vein. Embodiments of TLS 50 and systems incorporating TLS 50 are disclosed in U.S. Pat. nos. 8,388,541, U.S. Pat. No. 8,781,555, U.S. Pat. No. 8,849,382, U.S. Pat. No. 9,636,031, and U.S. Pat. No. 9,649,048, each of which is incorporated herein by reference in its entirety.

As mentioned, TLS 50 utilizes stylet 100 to enable distal tip 76A of catheter 72 to be tracked during its advancement through the vasculature. Fig. 4 shows an embodiment of a stylet 100 that includes a proximal end 100A and a distal end 100B. The handle 102 is included on the stylet body 1000 (see fig. 11) at the proximal end 100A of the stylet 100, with the core wire 104 extending distally from the handle 102 through the stylet body 1000. As shown in fig. 11, the magnetic assembly 1002 is distal to the core wire 104 or beside the core wire 104. The magnetic assembly 1002 includes one or more magnetic field generating elements 106. For example, a plurality of magnetic field generating elements 106 may be disposed adjacent to each other proximate the distal end 100B of the stylet 100 and enclosed by a flexible outer construct 108 (e.g., a flexible cannula) as shown in fig. 4. In practice, each of the one or more magnetic field generating elements 106 may comprise a solid cylindrical permanent magnet (e.g., a composite or ferrite magnet, a rare earth-free magnet, etc.) stacked end-to-end with the other magnetic field generating elements 106. The stylet tip 110 can be sealed with a filler 1004 (e.g., a conductive block, an adhesive such as conductive epoxy, etc.) in the distal tip of the outer construct 108 distal to the one or more magnetic field generating elements 106, thereby sealing the one or more magnetic field generating elements 106 in the distal portion of the stylet 100 of its stylet body 1000. Advantageously (see fig. 11), the one or more magnetic field generating elements 106 may thus be movable relative to the outer configuration 108, which enhances flexibility of the stylet 100 over directly adhering the one or more magnetic field generating elements 106 to the outer configuration 108. In practice, adhering the one or more magnetic field generating elements 106 directly to the outer construction 108 maintains the one or more magnetic field generating elements 106 in a fixed position relative to the outer construction 108.

Nevertheless, the one or more magnetic field generating elements 106 may differ from the foregoing magnetic field generating elements with respect to number, shape, size, or one or more dimensions, composition, magnet type, or location in the distal portion of the stylet 100. Indeed, other embodiments of the one or more magnetic field generating elements 106 are set forth below. For example, the magnetic assembly 1002 or one or more magnetic field generating elements 106 thereof may be a flexible electromagnetic assembly 1006, such as described below with respect to fig. 19, that generates a magnetic field that is detected by the TLS 50. Another embodiment of a magnetic assembly useful herein can be found in U.S.5,099,845 entitled "Medical Instrument Location Means (medical device positioning method)", the entire contents of which are incorporated herein by reference. Other embodiments of a stylet including a magnetic assembly that can be used with the TLS 50 include U.S.8,784,336, U.S.9,901,714, U.S.10,004,875, U.S.2018/0304043 and U.S.2018/0169389, each of which is incorporated herein by reference in its entirety. It should be understood that "stylet" as used herein may include any of a variety of devices configured for removable placement within the lumen of the catheter 72 to facilitate placement of the distal tip 76A of the catheter 72 at a desired location within the patient vasculature.

Fig. 2 illustrates the placement of the stylet 100 substantially within the lumen of the catheter 72 such that a proximal portion of the stylet 100 extends proximally from the lumen of the catheter tubing 71, through the hub 74A, and out through one of the one or more extension legs 74B. Disposed within the lumen of catheter 72, distal end 100B of stylet 100 is substantially co-terminal with distal tip 76A of catheter 72 such that detection of distal end 100B or stylet 100 by TLS 50 is indicative of the position of distal tip 76A of catheter 72, respectively.

The integrated system 10 employs the TLS 50 during operation to detect the magnetic field generated by the one or more magnetic field generating elements 106 of the stylet 100. As seen in fig. 2, TLS 50 is placed on the chest of patient 70 during insertion of catheter 72. The TLS 50 is placed at a predetermined location on the chest of the patient 70 (such as by using an external body marker) so that the magnetic field of one or more magnetic field generating elements 106 disposed in the catheter 72 can be detected during the passage of the catheter 72 through the patient's vasculature. Further, one or more magnetic field generating elements 106 of the magnetic assembly 1002 may be co-terminal with the distal tip 76A (see fig. 2) of the catheter 72. The detection of the magnetic field of the one or more magnetic field generating elements 106 by the TLS 50 provides information to the clinician regarding the position and orientation of the distal tip 76A of the catheter 72 during its passage.

In more detail, the TLS 50 is operatively connected to the console 20 of the integrated system 10 via one or more of the ports 52, as shown in fig. 1. Note that other connection schemes between TLS 50 and console 20 may be used without limitation. As just described, one or more magnetic field generating elements 106 are employed in the stylet 100 to enable the position of the distal tip 76A of the catheter 72 (see fig. 2) relative to the TLS 50 placed on the patient's chest to be observed. During TLS mode, detection of one or more magnetic field generating elements 106 by TLS 50 is graphically displayed on display 30 of console 20. In this manner, a clinician placing the catheter 72 is generally able to determine the position of the distal tip 76A of the catheter 72 within the vasculature of the patient relative to the TLS 50 and detect when a misalignment of the catheter 72 has occurred, such as advancement of the catheter 72 along an undesired vein.

Fig. 5A-5C depict screen shots taken from the display 30 of the integrated system 10 when in TLS mode, showing how the magnetic component 1002 of the stylet 100 is depicted. The screenshot 118 of FIG. 5A shows a representative image 120 of the TLS 50. Other information is provided on the screen shot 118 including a depth scale indicator 124, status or action markers 126, and button icons 128 corresponding to console button interfaces 32 included on the console 20 (see fig. 5C). Although button icons 128 are shown as relatively simple indicators to guide the user in identifying the use of the corresponding buttons of console button interface 32, in some embodiments, display 30 may be made touch-sensitive so that button icons 128 themselves may be used as button interfaces and changed according to the mode of integrated system 10.

During an initial stage of advancement of the catheter 72 through the patient's vasculature after insertion of the catheter 72 into the patient's vasculature, the distal tip 76A of the catheter 72 (with which the distal end 100B of the stylet 100 is substantially co-terminal) is relatively distant from the TLS 50. Thus, screen shot 118 indicates "no signal" indicating that the magnetic field from magnetic assembly 1002 of stylet 100 has not been detected. In fig. 5B, the magnetic assembly 1002 near the distal end 100B of the stylet 100 has been advanced close enough to the TLS 50 to be detected thereby, although it has not yet been under the TLS 50. This is indicated by the half icon 114A representing the distal portion of the stylet 100 or the magnetic assembly 1002 of the stylet 100, which is to the right of the TLS 50 from the perspective of the patient 70.

In fig. 5C, the magnetic assembly 1002 proximal to the distal end 100B of the stylet 100 has been advanced under the TLS 50 such that its position and orientation relative to the TLS is detected by the TLS 50. This is indicated by icon 114 on image 120. Note that the button icons 128 provide an indication of actions that may be performed by pressing the corresponding buttons of the console button interface 32. Thus, button icons 128 may be changed depending on the mode of integrated system 10, thereby providing flexibility of use for console button interface 32. It is further noted that since the control button pad of probe 40 includes control buttons that mimic several of the buttons of console button interface 32, button icons 128 on display 30 provide a guide for a clinician to control integrated system 10 with the control buttons of probe 40 while remaining in the sterile field. For example, if the clinician needs to leave TLS mode and return to US mode, the appropriate control buttons on the control button pad of the probe may be pressed and the US mode may be immediately invoked while the display 30 is refreshed to accommodate the visual information required for the US mode, such as that shown in fig. 3. This is accomplished without requiring the clinician to reach out of the sterile field.

Referring now to fig. 6 and 7, an integrated system 10 according to some embodiments is described. As previously described, the integrated system 10 includes a console 20, a display 30, a probe 40 for US visualization, and TLS 50 for TLS tracking. Note that the integrated system 10 depicted in fig. 6 and 7 is similar in many respects to the integrated system 10 shown in fig. 1 and 2. Thus, only selected differences are described below. The integrated system 10 of fig. 6 and 7 includes additional functionality for determining the proximity of the distal tip 76A of the catheter 72 relative to the sinoatrial ("SA") junction or other electrical pulse emitting junction of the heart of the patient 70, thereby providing an enhanced ability to accurately place the distal tip 76A of the catheter 72 in a desired location proximate the junction. Moreover, a third mode or ECG mode of the integrated system 10 enables detection of ECG signals from the SA knots in order to place the distal tip 76A of the catheter 72 at a desired location within the patient's vasculature. Note that the US mode, TLS mode, and ECG mode are seamlessly combined in the integrated system 10 of fig. 6, and may be used cooperatively or individually to aid in placement of the catheter 72.

Fig. 6 and 7 illustrate the addition of a stylet 130 to the integrated system 10. As an overview, the stylet 130 is removably pre-disposed within the lumen of the catheter 72, which is inserted into the patient 70 via the insertion site 73. In addition to the magnetic assembly 1002 of the stylet 100 for the TLS mode, the stylet 130 also includes an ECG sensor assembly proximate its distal end 130B for sensing ECG signals generated by the SA node. In contrast to stylet 100, stylet 130 also includes a tether 134 extending from a proximal end thereof that is operably connected to TLS 50. As part of the ECG pattern, tether 134 allows the transmission of ECG signals detected by the ECG sensor assembly of stylet 130 to TLS 50 during confirmation of the position of distal tip 76A of catheter 72. As shown in fig. 7, reference and ground ECG leads are attached to the body of patient 70 and to TLS 50, enabling integrated system 10 to filter out high levels of electrical activity independent of the electrical activity of the cardiac SA node, which in turn enables ECG-based tip confirmation. Along with reference and ground signals received from ECG leads placed on the patient's skin, the ECG signals sensed by the ECG sensor assembly of the stylet 130 are received by the TLS 50 located on the patient's chest (see fig. 7). TLS 50 or processor 22 may process ECG data corresponding to the ECG signal to generate an ECG waveform on display 30. In the case where TLS 50 processes ECG data, a processor is included to perform the intended functions. If the console 20 processes ECG data, a processor 22, digital controller/analog interface 24, or other processor may be used in the console 20 to process the data.

Thus, as the catheter 72 equipped with the stylet 130 is advanced through the vasculature of the patient, the catheter can be advanced under the TLS 50, which is positioned on the chest of the patient 70 as shown in fig. 7. This enables TLS 50 to detect the position of the magnetic assembly 1002 of stylet 130, which is substantially co-terminal with the distal tip 76A of catheter 72 located within the vasculature of the patient. During the ECG mode, detection of the magnetic component 1002 of the stylet 130 by the TLS 50 is depicted on the display 30. The display 30 further depicts the ECG waveforms generated during the ECG mode as a result of the patient's electrical cardiac activity detected by the ECG sensor assembly of the stylet 130. In more detail, the electrical activity of the SA node (including the P-wave of the waveform) is detected by the ECG sensor assembly of the stylet 130 and forwarded to the TLS 50 and console 20. The electrical activity of the SA node is then processed to be depicted on the display 30. The clinician placing the catheter 72 may then view the ECG data to determine the optimal placement of the distal tip 76A of the catheter 72, such as near the SA node. In some embodiments, the console 20 includes the electronics necessary to receive and process the signals detected by the ECG sensor assembly of the stylet 130, such as the processor 22 (see fig. 6). However, in some embodiments, TLS 50 may include the electronics necessary to receive and process the signals detected by the ECG sensor assembly of stylet 130.

As already discussed, the display 30 is used to display information to the clinician during placement of the catheter 72. The content of the display 30 varies depending on the mode of the integrated system 10 (i.e., US mode, TLS mode, ECG mode, or any combination of the foregoing). The clinician may immediately invoke any of these three modes to the display 30 and, in some cases, may display information from multiple modes (such as TLS and ECG modes) simultaneously. In some embodiments, as previously described, the mode of integrated system 10 may be controlled by control buttons of probe 40, thereby eliminating the need for a clinician to extend out of the sterile field to touch console button interface 32 of console 20 to change modes. Thus, the probe 40 may be used to also control some or all of the ECG related functions of the integrated system 10. Note that console button interface 32 or other input configuration may also be used to control system functions. Moreover, in addition to display 30, integrated system 10 may also employ audible information such as beeps, ringtones, etc. to assist the clinician during placement of catheter 72.

Referring now to fig. 8, various details of some embodiments of a stylet 130 that is removably loaded into the catheter 72 and used to position the distal tip 76A of the catheter 72 at a desired location within the patient vasculature during insertion are described. As shown, the stylet 130 includes a proximal end 130A and a distal end 130B. A tether connector 132 is included at the proximal end 130A of the stylet 130, and a tether 134 extends distally from the tether connector 132 and is attached to a handle 136. Core wire 138 extends distally from handle 136. In some embodiments, the stylet 130 is preloaded within the lumen of the catheter 72 such that the distal end 130B is substantially flush or co-terminal with the opening at the distal tip 76A (see fig. 7) of the catheter 72. Further, in such embodiments, the proximal portion of core wire 138, handle 136, and tether 134 extend proximally from one of the one or more extension legs 74B. Note that although described herein as a stylet, in other embodiments, a guidewire or other medical device guide apparatus may include certain operational features of the stylet 130.

The core wire 138 defines an elongated shape and is constructed of a suitable stylet material including stainless steel or memory material (such as nickel and titanium containing alloys commonly referred to as "nitinol"). Although not shown here, fabricating the core wire 138 from nitinol enables a portion of the core wire 138 corresponding to the distal section of the stylet 130 to have a preformed (e.g., curved) configuration in order to urge the distal portion 76 of the catheter 72 into a similar configuration. In other embodiments, core wire 138 does not include a preform. Further, the nitinol configuration imparts torqueability to the core wire 138 such that the core wire 138 is capable of manipulating at least the distal section of the stylet 130 when the stylet 130 is disposed within the lumen of the catheter 72, which in turn enables the distal portion 76 of the catheter 72 to be directed through the vasculature during insertion of the catheter 72.

A handle 136 is provided to enable insertion or removal of the stylet 130 from the catheter 72. In embodiments where the core wire 138 is torsionable, the handle 136 further enables the core wire 138 to rotate within the lumen of the catheter 72 to help direct the distal portion 76 of the catheter 72 through the vasculature of the patient 70.

A handle 136 is attached to the distal end of tether 134. Tether 134 may in turn be a flexible shielded cable containing one or more conductors electrically connected to both tether connector 132 and core wire 138, which serves as an ECG sensor assembly. Thus, tether 134 provides an electrically conductive path from the distal portion of core wire 138 to tether connector 132 at proximal end 130A of stylet 130. The tether connector 132 is configured for operative connection to the TLS 50 on the patient's chest to assist in directing the distal tip 76A of the catheter 72 to a desired location within the patient's vasculature.

As described above for stylet 100, external construct 108 (e.g., a cannula) encapsulates at least a portion of core wire 138 and magnetic assembly 1002 disposed proximate distal end 130B of stylet 130 for use during TLS mode of integrated system 10. The magnetic assembly 1002 includes one or more magnetic field generating elements 106 that may be disposed between an outer surface of the core wire 138 and an inner surface of the outer construct 108 proximate the distal end 130B of the stylet 130. The one or more magnetic field generating elements 106 may include up to at least 20 solid cylindrical permanent magnets stacked end-to-end in a manner similar to the stylet 100 of fig. 4. However, in other embodiments, one or more magnetic field generating elements 106 may differ with respect to number, shape, size, or one or more dimensions, composition, magnet type, or location in the distal portion of the stylet 130. For example, in some embodiments, for example, one or more magnetic field generating elements 106 of the magnetic assembly 1002 are replaced with electromagnets that generate a magnetic field for detection by the TLS 50.

One or more magnetic field generating elements 106 are used in the distal portion of the stylet 130 such that the position of the distal end 130B of the stylet 130 is observable relative to the TLS 50 placed on the patient's chest. As described above, TLS 50 is configured to detect the magnetic field generated by one or more magnetic field generating elements 106 as stylet 130 is advanced through the vasculature of the patient with catheter 72. In this manner, a clinician placing the catheter 72 is generally able to determine the position of the distal tip 76A of the catheter 72 within the patient's vasculature and detect when a misalignment of the catheter 72 has occurred.

The stylet 130 also includes the ECG sensor assembly described above. The ECG sensor assembly enables detection of intra-atrial ECG signals generated by the SA node or other node of the patient's heart using a stylet 130 disposed in the lumen of the catheter 72 during insertion, thereby allowing the distal tip 76A of the catheter 72 to be directed to a predetermined location within the vasculature proximate the patient's heart. Thus, the ECG sensor assembly serves as an aid in confirming proper placement of the distal tip 76A of the catheter 72.

In the embodiment illustrated in fig. 8, the ECG sensor assembly includes a distal portion of the core wire 138 disposed proximate the distal end 130B of the stylet 130. The core wire 138 is electrically conductive such that ECG signals can be detected by the distal end of the core wire and transmitted proximally along the core wire 138. A filler 1004 (e.g., a metal bump or a metal particle-containing epoxy) may fill a distal portion of the outer construct 108 that includes the stylet tip 110 (see fig. 4) adjacent to the distal end of the core wire 138 for conductive communication with the distal end of the core wire 138. This in turn increases the conductive surface of the distal end 130B of the stylet 130, thereby increasing its ability to detect ECG signals.

Before placement of the catheter 72, the stylet 130 is loaded into the lumen of the catheter 72. Note that the stylet 130 may be preloaded into the catheter 72 from the manufacturer or loaded into the catheter 72 by the clinician prior to placement of the catheter 72. The stylet 130 is disposed within the catheter 72 such that the distal end 130B of the stylet 130 is substantially co-terminal with the distal tip 76A of the catheter 72, thereby placing the distal tips of both the stylet 130 and the catheter 72 in substantial alignment with one another. The common end of the catheter 72 and stylet 130 enable the magnetic assembly 1002 to work with the TLS 50 in TLS mode to track the position of the distal tip 76A of the catheter 72 as it advances within the patient vasculature. However, for the tip verification function of the integrated system 10, the distal end 130B of the stylet 130 need not be co-terminal with the distal tip 76A of the catheter 72. Instead, all that is required is to establish a conductive path between the vasculature and the ECG sensor assembly of the core wire 138 so that electrical pulses of the SA or other junction of the patient's heart can be detected. This conductive path may include various components including saline solution, blood, and the like.

Once the catheter 72 has been introduced into the vasculature of a patient via the insertion site 73 (see fig. 7), the TLS mode of the integrated system 10 may be employed as has been described to advance the distal tip 76A of the catheter 72 toward its intended destination proximate to the SA node. Upon approaching the aforementioned destination, the integrated system 10 may switch to an ECG mode to enable detection of ECG signals emitted by the SA node. As the stylet-loaded catheter 72 is advanced toward the patient's heart, the conductive ECG sensor assembly, which includes the distal end of the core wire 138 and the conductive material in the stylet tip 110, begins to detect the electrical pulses generated by the SA node. Thus, the ECG sensor assembly serves as an electrode for detecting ECG signals. Core wire 138, which is proximal to the distal end of stylet 130, acts as a conductive path to transmit electrical pulses generated by the SA node and received by the ECG sensor assembly to tether 134.

Tether 134 transmits the ECG signal to TLS 50 which is temporarily placed on the patient's chest. Tether 134 is operably connected to TLS 50 via tether connector 132 or other suitable direct or indirect connection. The ECG signal may then be processed and depicted on the display 30 (see fig. 6 and 7) as described. Monitoring the ECG signal received by TLS 50 and displayed on display 30 enables the clinician to observe and analyze the change in ECG signal as distal tip 76A of catheter 72 advances toward the SA node. When the received ECG signal matches the desired curve, the clinician can determine that the distal tip 76A of the catheter 72 has reached the desired position relative to the SA node. As mentioned, in some implementations, this desired location is within the lower third of the SVC.

The ECG sensor assembly and the magnetic assembly 1002 can cooperate to assist a clinician in placing the catheter 72 within the vasculature of a patient. In general, the magnetic assembly 1002 of the stylet 130 helps the clinician generally direct the vasculature from initial insertion of the catheter 72 to placement of the distal tip 76A of the catheter 72 in a desired general region of the patient's heart. By enabling the clinician to observe the changes in the ECG signal produced by the patient's heart as the ECG sensor assembly of the stylet 130 approaches the SA node, the ECG sensor assembly can then be used to guide the distal tip 76A of the catheter 72 to a desired location within the SVC. Further, once the ECG signal matches the desired curve, the clinician can determine that the distal ends of both the stylet 130 and the catheter 72 have reached the desired position relative to the patient's heart. Once positioned as desired, the catheter 72 may be secured in place and the stylet 130 removed from the catheter 72. It is noted herein that the stylet 130 can include one of a variety of configurations in addition to those explicitly described herein. In some embodiments, the stylet 130 can be directly attached to the console 20, rather than indirectly via the TLS 50. In some embodiments, the structure of the stylet 130 that can perform its TLS and ECG related functions can be integrated into the catheter 72 itself. For example, in some embodiments, the magnetic assembly 1002 or ECG sensor assembly may be incorporated into the wall of the catheter 72.

Fig. 9 shows a typical ECG waveform 176 including P-wave and QRS complexes. Typically, the amplitude of the P-wave varies depending on the distance of the ECG sensor assembly from the SA node, which produces an ECG waveform 176. The clinician can use this relationship to determine when the distal tip 76A of the catheter 72 is properly positioned proximate to the heart. For example, in one implementation, the distal tip 76A of the catheter 72 is desirably placed within the lower third (1/3) of the superior vena cava. The ECG data detected by the ECG sensor assembly of the stylet 130 is used to reproduce waveforms such as ECG waveform 176 for depiction on the display 30 of the integrated system 10 during ECG mode.

Referring now to fig. 10, a display aspect of ECG data on the display 30 when the integrated system 10 is in ECG mode is described, according to some embodiments. The screen shot 178 of the display 30 includes elements of the TLS mode, such as the image 120 of the TLS 50 and the icon 114 corresponding to the position of the distal end 130B of the stylet 130 during passage through the vasculature of the patient. The screen shot 178 also includes a window 180 in which the current ECG waveform captured by the ECG sensor assembly of the stylet 130 is displayed. When a new waveform is detected, window 180 is continually refreshed.

Window 182 includes a continuous depiction of the most recently detected ECG waveform and a refresh bar 182A that moves laterally as the waveform is detected to refresh the waveform. For comparison purposes, window 184A is used to display a baseline ECG waveform captured prior to bringing the ECG sensor assembly close to the SA node to assist the clinician in determining when the desired position of distal tip 76A of catheter 72 has been reached. Windows 184B and 184C may be filled with user-selected ECG waveforms from those detected when the user presses a predetermined control button on either probe 40 or console button interface 32. The waveforms in windows 184B and 184C remain unchanged until overwritten by a new waveform as a result of a user selection via button presses or other inputs. A depth scale indicator 124, a status or action marker 126, and a button icon 128 are also included on the display 30. An integrity indicator 186 is also included on the display 30 to give an indication of whether the reference and ground ECG leads are operatively connected to the TLS 50.

Thus, in some embodiments, the display 30 depicts elements of both the TLS mode and the ECG mode simultaneously on a single screen, providing the clinician with sufficient data to assist in placing the distal tip 76A of the catheter 72 at the desired location. It is further noted that the screen shots 178 or selected ECG or TLS data may be saved, printed, or otherwise retained by the integrated system 10 to enable proper placement of the catheter 72 to be documented.

Fig. 4 and 8 illustrate stylet 100 and 130, respectively, according to some embodiments. Fig. 11 illustrates a stylet body 1000 of the stylet 100 and 130 according to some embodiments.

As shown, each of the magnetically trackable stylets 100 and 130 includes a stylet body 1000 configured to be disposed in a lumen of a medical device (such as one or more lumens of the catheter 72) for magnetically tracking a tip of the medical device in vivo. The stylet 1000 generally includes a core wire 104 or 138, an external construct 108, and a magnetic assembly 1002 including one or more magnetic field generating elements 106. Furthermore, the core wire 104 or 138 may be disposed in the distal portion of the stylet body 1000 alongside the one or more magnetic field generating elements 106, thereby enabling magnetic tracking of the stylet 100 or 130. However, the core wire 104 or 138 may alternatively be disposed through one or more magnetic field generating elements 106 in the distal portion of the stylet body 1000 (e.g., through the axial center of the one or more magnetic field generating elements 106). Obviously, these are different configurations than those set forth above with respect to fig. 4, wherein one or more magnetic field generating elements 106 are disposed distally of the core wire 104 or 138. Regardless of how the core wire 104 or 138 is disposed between the one or more magnetic field generating elements 106, the core wire 104 or 138 may taper in the distal portion of the stylet body 1000, as shown in fig. 11, to allow the one or more magnetic field generating elements 106 to be sized as desired. While certain embodiments of the magnetic assembly 1002, the outer configuration 108 of the stylet body 1000, etc. are described above with respect to the stylet 100 and 130, at least additional embodiments of the magnetic assembly 1002 and the outer configuration 108 of the stylet body 1000 are described below with respect to fig. 12-14, 15A, 15B, and 16-19, and 20A-20C, 21A and 21B, respectively.

Fig. 12 illustrates a detailed cross-sectional view of a distal portion of a stylet 100 or 130, according to some embodiments.

The one or more magnetic field generating elements 106 may include one or more polymer bonded magnets. The one or more polymer bonded magnets may comprise a single polymer bonded magnet molded as a cylinder. The one or more polymer bonded magnets may alternatively comprise a plurality of polymer bonded magnets molded as cylinders. Such polymer bonded magnets may include, but are not limited to, polymer bonded neodymium magnets. The one or more polymer bonded magnets are configured to enhance the bending resistance of the stylet body 1000, and thus the stylet 100 or 130. In practice, the one or more polymer bonded magnets are configured to bend and thus allow the stylet 1000 to bend according to the anatomy of the patient (e.g., vasculature) without kinking or fracturing the stylet 1000.

Advantageously, the shape, size (e.g., length), material (e.g., magnetic material, polymer, etc.), magnetic saturation, or loading of the single polymer bonded magnet or each of the plurality of polymer bonded magnets can be optimized to provide a desired balance between the magnetic field strength of the magnetic assembly 1002 and the flexibility (e.g., bending radius) of the distal portion of the stylet body 1000. Further, the outer construct 108 may be optimized for overall support, tensile strength, and flexibility.

Fig. 13 and 14 illustrate detailed cross-sectional views of distal portions of the stylet 100 or 130, according to some embodiments.

The one or more magnetic field generating elements 106 may include one or more sintered magnets. The one or more sintered magnets may include a plurality of sintered magnets cut and finished into a cylinder or even cone with flat or rounded ends (as shown in fig. 13 and 14). Alternatively, a plurality of cylindrical or conical sintered magnets may alternate with a plurality of spherical sintered magnets 1406 or a plurality of non-metallic spheres 1410 (and thus non-magnetic spheres), as shown in fig. 14. Such sintered magnets may include, but are not limited to, sintered neodymium magnets. Whether the plurality of cylindrical or conical sintered magnets include only rounded ends, or the plurality of cylindrical or conical sintered magnets include flat or rounded ends alternating with the plurality of spherical sintered magnets 1406 or nonmetallic spheres 1410 (e.g., thermoplastic spheres, elastomeric spheres, etc.), the distal portion of the stylet body 1000 so configured includes an articulatable joint 1308 or 1408 between at least the cylindrical magnets for enhanced bending resistance of the stylet 100 or 130. In practice, the fitting 1308 or 1408 is configured to allow at least the cylindrical magnets to bend toward each other. This in turn allows the stylet 1000 to bend according to the anatomy of the patient (e.g., vasculature) without kinking or fracturing the stylet 1000.

Fig. 15A, 15B, 16, and 17 illustrate detailed cross-sectional views of distal portions of the stylet 100 or 130, according to some embodiments.

Furthermore, the one or more magnetic field generating elements 106 may comprise one or more sintered magnets; however, as shown in fig. 15A, 15B, 16, and 17, one or more sintered magnets may be disposed in one or more magnet holders 1510, 1610, or 1710. The one or more sintered magnets may include a plurality of sintered magnets cut and finished into a cylinder having flat or rounded ends. As shown in fig. 15A and 15B, a plurality of sintered magnets may be disposed in a recess of a single magnet holder 1510 that includes a plurality of spacers 1512 disposed in the recess that segment the recess of the magnet holder 1510. In effect, the plurality of sintered magnets alternate with the plurality of spacers 1512 in the grooves of the magnet holder 1510, which spacers form the articulatable joints 1508 between the sintered magnets. As shown in fig. 16 and 17, a plurality of sintered magnets may alternatively be arranged in a plurality of magnet holders 1610 or 1710, forming an articulatable joint 1608 or 1708 therebetween. As shown in fig. 16, each of the plurality of magnet holders 1610 may encase one of the plurality of sintered magnets. Further, each of the plurality of magnet holders 1610 may include a ball end and a socket end such that the joint 1608 between the magnet holders 1610 is a ball joint. However, the plurality of magnet holders 1610 may include ball end magnet holders with paired ball ends alternating with socket end magnet holders with paired socket ends, which also provides a ball joint between the magnet holders 1610. As shown in fig. 17, each of the plurality of magnet holders 1710 may alternatively be a link or a chain ring, and the joint 1708 may be an interconnect between links that are linked together. Either single magnet holder 1510 of fig. 15A and 15B or multiple magnet holders 1610 or 1710 of fig. 16 or 17, joints 1508, 1608, and 1708 enhance the bending resistance of stylet 100 or 130. In effect, the joints 1508, 1608, and 1708 are configured to allow the plurality of sintered magnets to bend toward one another and thereby allow the stylet 100 or 130 to bend according to the anatomy of the patient without breaking.

Advantageously, the shape, size (e.g., length), magnetic material, magnetic saturation, or loading of each sintered magnet of the plurality of cylindrical, conical, or spherical sintered magnets can be optimized to provide a desired balance between the magnetic field strength of the magnetic assembly 1002 and the flexibility (e.g., bending radius) of the distal portion of the stylet body 1000. Likewise, the loading or ratio of the plurality of nonmetallic spheres 1410 to the plurality of cylindrical or conical sintered magnets can be optimized to provide a desired balance between the magnetic field strength of the magnetic assembly 1002 and the flexibility (e.g., bending radius) of the distal portion of the stylet body 1000. Further, the outer construct 108 may be optimized for overall support, tensile strength, and flexibility.

Fig. 18 and 19 illustrate detailed cross-sectional views of distal portions of the stylet 100 or 130, according to some embodiments.

As shown, if the core wire 104 or 138 is present, the one or more magnetic field generating elements 106 include one or more magnet wires surrounding the core wire 104 or 138. As shown in fig. 19, the one or more magnet wires may include a single magnet wire stranded with the core wire 104 or 138 or wrapped helically around the core wire 104 or 138. The one or more magnet wires may alternatively include a plurality of magnet wires stranded or braided around i) the core wire 104 or 138, ii) one of the plurality of magnet wires, or iii) one another, as shown in fig. 18. Such magnet wires may include, but are not limited to, neodymium magnet wires. Because of being flexible, the one or more magnet wires are configured to enhance bending resistance and allow the stylet 100 or 130 to bend according to the anatomy of the patient (e.g., vasculature) without kinking or fracturing the stylet body 1000.

As alternatively shown in fig. 19, the one or more magnetic field generating elements 106 may include one or more electromagnets surrounding the core wire 104 or 138. The one or more electromagnets may comprise a single electromagnet formed of a wire wrapped helically around the core wire 104 or 138 for generating a magnetic field when current is supplied. Alternatively, the one or more electromagnets may comprise a plurality of electromagnets formed of a plurality of wires helically wrapped around the core wire 104 or 138 for generating a magnetic field when a current is supplied. For a linear array of multiple electromagnets, each of the wires may be wrapped helically around a dedicated section of the core wire 104 or 138 and electrically insulated from the other wire and the core wire 104 or 138. Because of being flexible, the one or more wires are configured to enhance bending resistance and allow the stylet 100 or 130 to bend according to the anatomy of the patient (e.g., vasculature) without kinking or fracturing the stylet body 1000.

Advantageously, the dimensions (e.g., diameter, length, etc.), magnetic or conductive materials (e.g., the same magnetic or conductive material for multiple magnetic wires or leads or a mixture of different magnetic or conductive materials), magnetic saturation, the winding of a single lead or multiple leads, or the twisting or braiding of multiple magnetic wires or leads can be optimized to provide a desired balance between the magnetic field strength of the magnetic assembly 1002 and the flexibility (e.g., bending radius) of the distal portion of the stylet body 1000. Further, the outer construct 108 may be optimized for overall support, tensile strength, and flexibility.

Fig. 20A-20C, 21A and 21B illustrate various detailed cross-sectional views of a distal portion of a stylet 100 or 130 including various external configurations, according to some embodiments.

The outer construction 108 may be a single layer (i.e., a single layer outer construction) as shown in fig. 20A and 21A, or multiple layers (i.e., multiple layer outer construction) as shown in fig. 20B, 20C, and 21B. With respect to the single layer outer construction 108, such outer construction may include at least a primary layer 1206 of an over-mold layer, a reflow layer, an potting layer, or a shrink wrap layer. With respect to the multi-layer outer construction 108, such outer construction may include a primary layer 1206 with one or more other layers above or below it, such as a secondary layer 1208, a tertiary layer 1210, and the like. If the external construct 108 includes two or more other layers (such as a secondary layer 1208 and a tertiary layer 1210) in addition to the primary layer 1206, the two or more other layers may be above, below, or any combination of above and below the primary layer 1206.

With respect to the main layer 1206 being an overmolded layer, the overmolded layer may be molded around the core wire 104 or 138 and the magnetic assembly 1002, as shown in fig. 20A. The one or more gaps between any two or more magnetic field generating elements 106, if present, may include an over-molded layer of polymeric material therebetween, thereby forming one or more articulatable joints 1212 in the magnetic assembly 1002. The polymeric material may be an elastomeric or thermoplastic polymer such as acrylic, acrylonitrile butadiene styrene ("ABS"), polyamide (e.g., nylon), polylactic acid, polybenzimidazole, polycarbonate, polyethersulfone, polyoxymethylene, polyetheretherketone ("PEEK"), polyetherimide, polyethylene, polyphenylene oxide, polyphenylene sulfide, polypropylene, polystyrene, polyvinylchloride, polyvinylidene fluoride, or polytetrafluoroethylene ("PTFE"). Because one or more gaps between two or more magnetic field generating elements 106 can be adjusted in their width prior to molding (e.g., injection molding) over magnetic assembly 1002, one or more articulatable joints 1212 can be optimized to achieve a desired balance between flexibility (e.g., bending radius) and magnetic field strength of magnetic assembly 1002 in the distal portion of stylet body 1000.

With respect to the main layer 1206 being a reflow layer, the reflow layer can be molded around the core wire 104 or 138 and the magnetic assembly 1002 and then reflowed around the core wire 104 or 138 and the magnetic assembly 1002, as shown in fig. 20A. The one or more gaps between any two or more magnetic field generating elements 106, if present, may include a polymeric material of the reflow layer therebetween, thereby forming one or more articulatable joints 1212 in the magnetic assembly 1002. The polymeric material may be a thermoplastic polymer such as acrylic, acrylonitrile butadiene styrene ("ABS"), polyamide (e.g., nylon), polyether copolyamide ("PEBA"), polyurethane, polylactic acid, polybenzimidazole, polycarbonate, polyethersulfone, polyoxymethylene, polyetheretherketone ("PEEK"), polyetherimide, polyethylene, fluorinated ethylene propylene ("FEP"), polyphenylene oxide, polyphenylene sulfide, polypropylene, polystyrene, polyvinylchloride, polyvinylidene fluoride ("PVDF"), or polytetrafluoroethylene ("PTFE"). Because one or more gaps between two or more magnetic field generating elements 106 can be adjusted in their width prior to molding (e.g., injection molding) over magnetic assembly 1002 and reflowing the thermoplastic polymer, one or more hingeable joints 1212 can be optimized to achieve a desired balance between flexibility (e.g., bending radius) and magnetic field strength of magnetic assembly 1002 in the distal portion of stylet body 1000.

With respect to the main layer 1206 being a potting layer, the potting layer may be potted around the core wire 104 or 138 and the magnetic assembly 1002, as shown in fig. 20A. The one or more gaps between any two or more magnetic field generating elements 106, if present, may include potting material of a potting layer therebetween, forming one or more articulatable joints 1212 in the magnetic assembly 1002. The potting material may be a thermosetting polymer such as epoxy, polyurethane or silicone. Because one or more gaps between two or more magnetic field generating elements 106 can be adjusted in their width prior to potting the potting material on the magnetic assembly 1002, one or more of the articulatable joints 1212 can be optimized to achieve a desired balance between flexibility (e.g., bending radius) and magnetic field strength of the magnetic assembly 1002 in the distal portion of the stylet body 1000.

With respect to the main layer 1206 being a shrink wrap layer, the shrink wrap layer may shrink around the core wire 104 or 138 and the magnetic assembly 1002, as shown in fig. 21A. The one or more gaps between any two or more magnetic field generating elements 106, if present, may include air or spacers therebetween, optionally with some conformable shrink wrap that shrinks into the outer diameter of the one or more gaps, thereby forming one or more articulatable joints 1212 in the magnetic assembly 1002. The shrink wrap layer may be a thermoplastic polymer such as a polyolefin (e.g., polyethylene, polypropylene, polybutylene), a fluoropolymer (e.g., PTFE), or polyvinyl chloride ("PVC"). Because one or more gaps between two or more magnetic field generating elements 106 can be adjusted in their width prior to shrinking the shrink wrap over the magnetic assembly 1002, one or more of the articulatable joints 1212 can be optimized to achieve a desired balance between flexibility (e.g., bending radius) and magnetic field strength of the magnetic assembly 1002 in the distal portion of the stylet body 1000.

Further, the outer configuration 108 may be a single layer (i.e., a single layer outer configuration) as shown in fig. 20A and 21A, or a multiple layer (i.e., a multiple layer outer configuration) as shown in fig. 20B, 20C, and 21B. With respect to the multi-layer outer construction 108, such outer construction may include a primary layer 1206 with one or more other layers above or below it, such as a secondary layer 1208, a tertiary layer 1210, and the like. For example, fig. 20B and 21B illustrate a primary layer 1206 (e.g., an overmolded layer, a reflow layer, an encapsulating layer, or a shrink wrap layer) along with a secondary layer 1208 thereon. In such embodiments, the secondary layer 1208 may be a sleeve or tubing over the primary layer 1206. In another embodiment, FIG. 20C shows a primary layer 1206 with a secondary layer 1208 and a tertiary layer 1210 thereon. In such embodiments, the secondary layer 1208 may be a sleeve or tubing over the tertiary layer 1210, which may be a woven layer. When the primary layer 1206 is a reflow layer, the polymeric material of the reflow layer may reflow into one or more gaps between any two or more magnetic field generating elements 106 and into the braid, thereby forming the composite outer construction 108.

Finally, the method includes a method of using a magnetically trackable stylet. For example, such methods may include a catheterization step, a catheter advancement step, and a catheter placement step. The catheterization step includes inserting a catheter 72 into an insertion site 73 of the patient 70. Catheter 72 includes stylet 100 or 130 disposed in the lumen of catheter 72 such that distal end 100B or 130B of stylet 100 or 130 is substantially co-terminal with distal tip 76A of catheter 72. The catheter advancement step includes advancing the catheter 72 through the vasculature of the patient 70 without fracturing the stylet body 1000 of the stylet 100 or 130 due to bending-related fatigue. As described above, the stylet 100 or 130 includes the outer configuration 108 of the magnetic assembly 1002 surrounding one or more magnetic field generating elements 106 disposed in the magnetically trackable distal portion of the stylet body 1000 alongside the core wire 104 or 138. The catheter placement step includes placing the distal tip 76A of the catheter 72 in a desired general area near the patient's heart based on the magnetic tracking of the TLS 50 of the integrated system 10 for placement of the catheter 72.

Although certain embodiments have been disclosed herein, and while these particular embodiments have been disclosed in considerable detail, these particular embodiments are not intended to limit the scope of the concepts provided herein. Additional adaptations or modifications may be apparent to those of ordinary skill in the art, and in a broader aspect, are also included. Accordingly, departures may be made from the specific embodiments disclosed herein without departing from the scope of the concepts provided herein.

Claims

1. A magnetically trackable stylet, comprising:

a stylet body having a magnetically trackable distal portion, the stylet body comprising:

a core wire;

a flexible magnetic assembly comprising one or more magnetic field generating elements disposed in a distal portion of the stylet body alongside the core wire; and

a cannula surrounding the core wire and the magnetic assembly, the stylet body configured to be disposed in a lumen of a catheter for magnetically tracking a catheter tip in vivo without the stylet body breaking due to bending-related fatigue.

2. The stylet of claim 1, wherein the core wire tapers in a distal portion of the stylet body alongside the one or more magnetic field generating elements.

3. The stylet of claim 1, further comprising a sealed stylet tip comprising a seal sealing the one or more magnetic field generating elements in a distal portion of the stylet body.

4. The stylet of claim 1, wherein the one or more magnetic field generating elements comprise one or more polymer bonded magnets configured to bend and thereby allow the stylet to bend according to patient anatomy without breaking.

5. The stylet of claim 4, wherein the one or more polymer bonded magnets comprise a single cylindrical polymer bonded magnet.

6. The stylet of claim 4, wherein the one or more polymer bonded magnets comprise a plurality of cylindrical polymer bonded magnets.

7. The stylet of claim 1, wherein the one or more magnetic field generating elements comprise one or more sintered magnets.

8. The stylet of claim 7, wherein the one or more sintered magnets comprise a plurality of cylindrical sintered magnets having rounded ends configured to allow the cylindrical sintered magnets to bend toward each other and thereby allow the stylet to bend according to patient anatomy without breaking.

9. The stylet of claim 7, wherein the one or more sintered magnets comprise a plurality of cylindrical sintered magnets alternating with a plurality of spherical sintered magnets forming an articulatable joint therebetween, the joint configured to allow the cylindrical sintered magnets to flex toward one another and thereby allow the stylet to flex according to patient anatomy without breaking.

10. The stylet of claim 7, wherein the one or more sintered magnets comprise a plurality of cylindrical sintered magnets alternating with a plurality of nonmetallic spheres forming an articulatable joint therebetween, the joint configured to allow the cylindrical sintered magnets to bend toward one another and thereby allow the stylet to bend according to patient anatomy without breaking.

11. The stylet of claim 7, wherein the one or more sintered magnets comprise a plurality of cylindrical sintered magnets alternating with a plurality of septa that segment grooves of a magnet holder in which the sintered magnets are disposed, the septa forming articulatable joints between the cylindrical sintered magnets configured to allow the cylindrical sintered magnets to flex toward one another and thereby allow the stylet to flex according to patient anatomy without breaking.

12. The stylet of claim 7, wherein the one or more sintered magnets comprise a plurality of cylindrical sintered magnets disposed in a plurality of magnet holders that form an articulatable joint therebetween, the joint configured to allow the cylindrical sintered magnets to flex toward one another and thereby allow the stylet to flex according to patient anatomy without breaking.

13. The stylet of claim 12, wherein each of the magnet holders comprises a ball end and a socket end, the joint being a ball joint.

14. The stylet of claim 12, wherein the magnet holder comprises a ball end magnet holder having a pair of ball ends and a socket end magnet holder having a pair of socket ends, the joint being a ball joint.

15. The stylet of claim 12, wherein the magnet holder is a link and the connector is an interconnect between links that are linked together.

16. The stylet of claim 1, wherein the one or more magnetic field generating elements comprise one or more magnet wires stranded or braided with the core wire, the one or more magnet wires configured to bend and thereby allow the stylet to bend according to patient anatomy without breaking.

17. A magnetically trackable stylet, comprising:

a flexible magnetic assembly of one or more magnet wires in a distal portion of the stylet body; and

A cannula surrounding the magnetic assembly, the stylet configured to be disposed in a lumen of a catheter for magnetically tracking a catheter tip in vivo without the stylet causing breakage due to bending-related fatigue.

18. The stylet of claim 17, wherein the one or more magnet wires comprise a single magnet wire.

19. The stylet of claim 18, further comprising a core wire in a distal portion of the stylet body, the magnet wire being stranded with the core wire.

20. The stylet of claim 18, further comprising a core wire in a distal portion of the stylet body, the magnet wire helically wrapping around the core wire.

21. The stylet of claim 17, wherein the one or more magnet wires comprise a plurality of magnet wires.

22. The stylet of claim 21, further comprising a core wire in a distal portion of the stylet body, the magnet wire being stranded or braided with the core wire.

23. The stylet of claim 21, further comprising a core wire in a distal portion of the stylet body about which the magnet wire is stranded or braided.

24. The stylet of claim 17, further comprising a sealed stylet tip comprising a seal that seals the magnet wire in a distal portion of the stylet body.

25. A magnetically trackable stylet, comprising:

a core wire;

a magnetic assembly comprising one or more magnetic field generating elements disposed in a distal portion of the stylet body alongside the core wire; and

an external configuration over the core wire and the magnetic assembly, the external configuration selected from the group consisting of an over-molded layer, a reflow layer, an encapsulating layer, and a shrink wrap layer, the stylet configured to be disposed in a lumen of a catheter for magnetically tracking a catheter tip in vivo without the stylet causing breakage due to bending-related fatigue.

26. The stylet of claim 25, wherein the outer configuration is a single layer outer configuration.

27. The stylet of claim 26, wherein the external construct comprises the overmolded layer molded around the core wire and the magnetic assembly.

28. The stylet of claim 27, wherein the one or more gaps between any two or more magnetic field generating elements comprise a polymeric material of the overmolded layer therebetween that forms one or more articulatable joints in the magnetic assembly.

29. The stylet of claim 26, wherein the external construct comprises the reflow layer reflowing around the core wire and the magnetic assembly.

30. The stylet of claim 29, wherein the one or more gaps between any two or more magnetic field generating elements comprise a polymeric material of the reflow layer therebetween that forms one or more articulatable joints in the magnetic assembly.

31. The stylet of claim 26, wherein the external construct comprises the potting layer potted around the core wire and the magnetic assembly.

32. The stylet of claim 31, wherein the one or more gaps between any two or more magnetic field generating elements comprise potting material of the potting layer therebetween, which forms one or more articulatable joints in the magnetic assembly.

33. The stylet of claim 26, wherein the outer construct comprises the shrink wrap layer shrunk around the core wire and the magnetic assembly.

34. The stylet of claim 33, wherein one or more gaps between any two or more magnetic field generating elements form one or more articulatable joints in the magnetic assembly.

35. The stylet of claim 25, wherein the outer construct is a multi-layer outer construct.

36. The stylet of claim 35, wherein the external construct comprises the overmolded layer molded around the core wire and the magnetic assembly and one or more other layers over the overmolded layer.

37. The stylet of claim 36, wherein the one or more gaps between any two or more magnetic field generating elements comprise a polymeric material of the overmolded layer therebetween that forms one or more articulatable joints in the magnetic assembly.

38. The stylet of claim 36, wherein the one or more other layers comprise a cannula disposed over the overmolded layer.

39. The stylet of claim 35, wherein the external construct comprises the reflow layer reflowing around the core wire and the magnetic assembly and one or more other layers above the reflow layer.

40. The stylet of claim 39, wherein the one or more gaps between any two or more magnetic field generating elements comprise a polymeric material of the reflow layer therebetween that forms one or more articulatable joints in the magnetic assembly.

41. The stylet of claim 39, wherein the one or more other layers comprise a braid over the reflux layer and an outer cannula over the braid, the reflux layer reflowing into the braid.

42. The stylet of claim 35, wherein the external construct comprises the potting layer potting around the core wire and the magnetic assembly and one or more other layers above the potting layer.

43. The stylet of claim 42, wherein the one or more gaps between any two or more magnetic field generating elements comprise potting material of the potting layer therebetween, forming one or more articulatable joints in the magnetic assembly.

44. The stylet of claim 42, wherein the one or more other layers comprise a cannula disposed over the potting layer.

45. The stylet of claim 35, wherein the outer construct comprises the shrink wrap layer shrunk around the core wire and the magnetic assembly and one or more other layers over the shrink wrap layer.

46. The stylet of claim 45, wherein one or more gaps between any two or more magnetic field generating elements form one or more articulatable joints in the magnetic assembly.

47. The stylet of claim 45, wherein the one or more other layers comprise a cannula disposed over the shrink wrap layer.

48. The stylet of claim 25, wherein the core wire tapers in a distal portion of the stylet body alongside the one or more magnetic field generating elements.

49. The stylet of claim 25, further comprising a sealed stylet tip comprising a seal sealing the one or more magnetic field generating elements in a distal portion of the stylet body.