Medical delivery sheath equipped with an ultrasound imaging probe

Abstract

Medical delivery sheath equipped with an ultrasound imaging probe. This description relates to a medical delivery sheath (200) extending along an axial direction (X) between a distal end (200A) and a proximal end (200B), and comprising an axial lumen (204) and a flexible portion (210) extending to the distal end, the flexible portion comprising: - an ultrasound imaging probe (220) comprising several ultrasound transducers distributed in an array on a transverse face (200C) of the medical delivery sheath at the distal end around the axial lumen; - an orientation coupler (211) adapted to impart a curvature to the flexible portion; - a sleeve (215) disposed around the orientation coupler and comprising a tubular portion (216) and a protruding peripheral portion (217). wound in several projecting turns (219) around the tubular portion along the axial direction;and connecting bands (231) extending from the transducers in the axial direction towards the proximal end and distributed around the sheath; and an elastic structure (218) wound in several turns around the sheath and the connecting bands, the elastic structure running between the protruding turns. Figure for the abstract: Fig. 2B;

Description

Title of the invention: Medical delivery sheath equipped with an ultrasound imaging probe. Technical field

[0001] This description relates generally to intracorporeal exploration and intervention devices intended to be introduced, at least partially, into an anatomical region of a patient, and equipped with an ultrasound imaging probe that can be directed towards the anatomical region of the patient.

[0002] The present description relates in particular to a medical introduction sheath, for example a trocar or a cannula, equipped with an ultrasound imaging probe integrated at a distal end of the medical introduction sheath.

[0003] The medical introduction sheath includes, for example, an internal lumen adapted to receive a catheter, or any other elongated medical device. Previous technique

[0004] Certain exploration and intervention techniques in anatomical regions, such as cardiac regions, use imaging, for example fluoroscopy or fluoroscopy (i.e. X-ray imaging), to help locate and guide medical devices to a target region of the patient, usually through the patient's vascularization.

[0005] Medical devices that can be guided into a patient's body typically include access devices, or medical introduction sheaths, for example trocars or cannulas, diagnostic catheters, and / or treatment catheters, for example ablation or replacement catheters.

[0006] Ultrasound imaging catheters and probes have been developed to directly visualize the target region. For example, a catheter incorporating an ultrasound imaging probe, or imaging catheter, can be used to image the target region and then guide an access device and a treatment catheter into that target region.

[0007] However, generally, the imaging catheter is separate from the access device and the treatment catheter. On the one hand, this requires multiple insertion / removal procedures for the various devices, and even multiple access points, within the patient's body, with the associated risks and discomfort for the patient, and consequently lengthening the procedure time. On the other hand, it requires positional tracking to monitor the location of each device within the patient's body, which is generally performed using fluoroscopy, potentially increasing the exposure of both the patient and medical personnel to X-rays. This can Furthermore, it requires cross-referencing positioning between different devices, which can be an additional source of wasted time.

[0008] It would be desirable to have an exploration and intervention device that at least partially overcomes some of the drawbacks of known intracorporeal exploration and intervention devices.

[0009] In particular, there is a need for a medical delivery sheath that is suitable for receiving a catheter or other elongated medical device and that includes an imaging function. It would be advantageous if the medical delivery sheath could be easily orientable so as to be guided towards a target anatomical region. Summary of the invention

[0010] One embodiment overcomes all or part of the drawbacks of known exploration and intervention devices.

[0011] One embodiment provides a medical delivery sheath extending in an axial direction between a distal end and a proximal end opposite the distal end, the medical delivery sheath having an internal axial lumen between said distal end and said proximal end, and a flexible portion extending to said distal end, the flexible portion comprising: - an ultrasound imaging probe comprising several ultrasound transducers distributed in a matrix on a transverse face of the medical introduction sheath at the distal end, around the axial lumen; - an orientation coupler adapted to impart a curvature to the flexible portion; - a sheath arranged around the orientation coupler, said sheath comprising a tubular portion and a protruding peripheral portion wound in several turns projecting around the tubular portion, along the axial direction, the tubular portion being situated between the peripheral portion and the orientation coupler; and - connecting strips extending from the ultrasonic transducers in the axial direction towards the proximal end and distributed around the sheath; and - an elastic structure wound in several turns around the sheath and connecting bands, the elastic structure running between the protruding turns.

[0012] According to one embodiment, the peripheral portion has a helical shape, the protruding turns corresponding to the turns of the helix, the elastic structure also having a helical shape running between the protruding turns.

[0013] According to one embodiment, the projecting towers of the peripheral portion are projecting rings that are disjoint from each other and distributed, for example regularly distributed, over several circumferences of the tubular portion along the axial direction, the turns of the elastic structure also being rings disjoint from each other and positioned between the protruding rings.

[0014] According to one embodiment, the pitch between the turns of the elastic structure is substantially equal to the pitch between the protruding turns of the peripheral portion, the turns of the elastic structure being distributed regularly along the axial direction.

[0015] According to one embodiment, the pitch between the turns of the elastic structure is substantially equal to the pitch between the protruding turns of the peripheral portion, the turns of the elastic structure being distributed irregularly along the axial direction, for example with a greater density around a center of the flexible portion.

[0016] According to one embodiment, the axial lumen is dimensioned to receive a catheter in a sliding and / or rotating manner.

[0017] According to one embodiment, the orientation coupler comprises links, for example ball joints, two adjacent links cooperating with each other so as to be able to pivot around at least one axis of rotation.

[0018] According to one embodiment, the orientation coupler includes linkage cables connected to the links so as to hold the links against each other, and to control the pivoting of the links, and thus a bending of the flexible portion.

[0019] According to one embodiment, the ultrasonic transducers of the ultrasonic probe are distributed in several concentric rings around the axial lumen, each ring comprising several transducers distributed in radial sectors along said ring, for example the number of rings is greater than 3 and the number of transducers per ring is greater than 30.

[0020] According to one embodiment, the ultrasonic transducers are piezoelectric transducers and are formed by several annular layers extending one on top of the other around the axial light, said annular layers comprising: - a piezoelectric layer metallized on each of its internal and external faces, and divided into several piezoelectric sectors, for example annular and radial sectors; - an impedance matching layer on the piezoelectric layer, divided into several impedance matching sectors, each impedance matching sector being positioned opposite a piezoelectric sector; and - an acoustic attenuation layer, under the piezoelectric layer.

[0021] According to one embodiment, the medical introduction sheath further comprises an interconnection structure including the connection strips, the structure interconnection further comprising an annular portion disposed between the acoustic attenuation layer and the piezoelectric layer, said annular portion comprising metallic tracks connected to the ultrasonic transducers and extending into the connection bands.

[0022] According to one embodiment, the medical introduction sheath further comprises an annular tip at the distal end, said tip being connected to the orientation coupler, for example to a distal link of said orientation coupler, the ultrasonic transducers being arranged in a circumferential groove of said tip all around the axial lumen.

[0023] According to one embodiment, the medical introduction sheath further comprises an outer envelope around the connecting bands, the sheath and the elastic structure, the outer envelope being for example made of a biocompatible material.

[0024] One embodiment provides for an intracorporeal exploration and intervention device comprising a medical introduction sheath as described above.

[0025] According to one embodiment, the device further comprises a catheter configured to be introduced into the axial lumen of the medical introduction sheath.

[0026] According to one embodiment, the device further comprises, at the proximal end, a control handle adapted to control a flexion of the flexible portion.

[0027] According to one embodiment, the medical introduction sheath is a trocar.

[0028] One embodiment provides a method of using the introduction sheath.

[0029] According to one embodiment, the method of use includes using the introduction sheath for the treatment of a cardiac pathology, for example to implant a pacemaker, to perform radiofrequency ablation, to replace or implant a heart valve. Brief description of the drawings

[0030] These features and advantages, as well as others, will be described in detail in the following description of particular embodiments, given by way of non-limiting example, in relation to the accompanying figures, among which:

[0031] [Fig.1] is an overview of an intracorporeal exploration and intervention device according to one embodiment;

[0032] [Fig.2A], [Fig.2B] and [Fig.2C] are longitudinal sectional views partially representing an example of a medical introduction sheath according to one embodiment;

[0033] [Fig.3A] and [Fig.3B] are three-dimensional views of the medical introduction sheath of figures 2A to 2C;

[0034] [Fig. 3C] and [Fig. 3D] are views representing the interconnection structure of the medical delivery sheath of Figures 3A and 3B; and

[0035] Figure 4 is a schematic view representing an example of an ultrasound imaging probe for a medical delivery sheath according to one embodiment. Description of embodiments

[0036] The same elements have been designated by the same reference numerals in the different figures. In particular, the structural and / or functional elements common to the different embodiments may have the same reference numerals and may have identical structural, dimensional and material properties.

[0037] For the sake of clarity, only the steps and elements useful for understanding the described embodiments have been shown and are detailed. In particular, the ultrasonic transducers of the described ultrasonic probes have not been detailed, as the described embodiments are compatible with all or most known ultrasonic transducer structures.

[0038] Unless otherwise specified, when referring to two elements connected together, this means directly connected without intermediate elements other than conductors, and when referring to two elements coupled together, this means that these two elements can be connected or linked through one or more other elements.

[0039] Unless otherwise specified, when reference is made to two elements mounted, or positioned, one on top of the other, this does not necessarily mean that these two elements are mounted, or positioned, directly one on top of the other, one or more other elements being able to be positioned between these two elements.

[0040] In the following description, when reference is made to absolute position qualifiers, such as the terms "front", "back", "top", "bottom", "left", "right", etc., or relative position qualifiers, such as the terms "above", "below", "superior", "inferior", etc., or to orientation qualifiers, such as the terms "horizontal", "vertical", etc., reference is made, unless otherwise specified, to the orientation of the figures.

[0041] Unless otherwise specified, the expressions "approximately", "roughly", and "on the order of" mean to within 10% or 10°, preferably to within 5% or 5°.

[0042] In the following description, unless otherwise specified, when a transducer is referred to, it is an ultrasound transducer; when a probe is referred to, it is an ultrasound imaging probe; and when a sheath or an introduction sheath is referred to, it is a medical introduction sheath. A medical introduction sheath may, for example, being a trocar or cannula, or any other medical instrument that allows a passage to be formed in an anatomical region.

[0043] In the following description, reference is made to a catheter, broadly defined, to a thin rod-shaped device, hollow or solid, generally comprising at least one flexible portion, and intended to be introduced into a region of a human or animal body (e.g., a cavity, a light or lumen, or a conduit).

[0044] Fig. 1 is an overview of an intracorporeal exploration and intervention device 10 according to one embodiment.

[0045] The device 10 comprises a medical introduction sheath 100, and a control handle 12 connected to the proximal end 100B of the sheath 100. The sheath 100 is intended to be introduced into a human or animal anatomical region, for example to explore and / or intervene in that anatomical region.

[0046] The sheath 100 has a tubular rod shape 102 along its length, defining an axial lumen 104 internal to the tubular rod 102. The axial lumen 104 is adapted to receive a catheter, or any other elongated medical device (not shown). For example, the internal axial lumen 104 is dimensioned to receive a catheter by sliding and / or rotating it. The length of the catheter can be substantially equal to the length of the sheath 100 and the tubular rod 102.

[0047] The sheath 100 includes a flexible portion 110, or orientable portion, that is to say a portion which can be curved to adapt to the anatomy of the region into which it is introduced, for example up to an angle between 90° and 180° with respect to the axial direction X. The flexible portion 110 extends over a portion of the sheath 100 up to the distal end 100A of the sheath 100. The flexible portion 110 has, for example, a length of a few centimeters (cm), for example about 4 cm.

[0048] The control handle 12 is adapted to control the advancement and positioning of the sheath 100, as well as the flexion, or curvature, of the flexible portion 110 of the sheath 100.

[0049] The sheath 100 includes, at its distal end 100A, which is also the distal end of the flexible portion 110, an ultrasonic imaging probe 120. For example, the probe 120 extends all around the axial lumen 104 at the distal end 100A.

[0050] Throughout this description, the term "proximal" (or "rear") refers to the device as a whole, i.e., in the direction of the control handle, and the term "distal" (or "front") refers to the opposite direction, toward the area of ​​exploration and / or intervention (target region). The distal end of the medical delivery sheath corresponds to the end through which this sheath is introduced into the target region, and the proximal end corresponds to the end opposite the distal end.

[0051] Throughout this description, the term "axial" refers to the axis, in the X direction, of the device 10, i.e., its longest dimension, which also corresponds to the longest dimension of the sheath 100. A "radial" direction is a direction in a plane perpendicular to the axial direction X. Longitudinal refers to a direction parallel to the axial direction X, and transverse refers to a plane or direction perpendicular to the axial direction X. A longitudinal section is a section made in a plane including the X direction, while a transverse section is a section made in a plane perpendicular to the X direction including the radial direction.

[0052] The probe 120 is forward-facing, that is, oriented from the distal end 100A of the sheath 100 in the direction of advancement of the sheath 100. In other words, the sheath 100, with the probe 120 at its distal end 100A, is capable of transmitting and receiving ultrasound signals in a generally forward direction. The probe 120 allows visualization of anatomical regions located opposite the distal end 100A of the sheath 100. In particular, the probe 120 allows visualization of the target anatomical region during the procedure, or even before and / or after the procedure, without having to introduce another catheter equipped with an imaging probe.

[0053] For example, the probe 120 can provide real-time ultrasound images of anatomical regions in the direction of advancement of the sheath 100 through the patient's body. For example, the ultrasound images generated from the probe 120 can be used to guide the sheath 100 to the target region, confirm tissue contact of a catheter in the target region, determine the orientation of the sheath 100 and / or the catheter in the patient's body, monitor the progression of a developing lesion in the tissue, or even monitor adjacent anatomical structures, for example, to avoid undesirable collateral effects on these structures, monitor the progress and effectiveness of the treatment...

[0054] Advantageously, the sheath 100 equipped with the probe 120 can be used to deploy a catheter into the target anatomical region. Advantageously, the sheath 100 equipped with the probe 120 can considerably reduce, or even eliminate, the use of fluoroscopy as a means of visualizing the sheath 100 and the catheter during a procedure. In other words, the ultrasonic guidance provided by the sheath 100 makes it possible to limit, or even eliminate, the need for fluoroscopic guidance when introducing the sheath to a target region.

[0055] In a particular, non-limiting embodiment, the sheath 100 can be used in association with a positioned catheter in axial lumen 104, for implanting a pacemaker, for performing radiofrequency ablation (RF ablation) or cryoablation, or for replacing or implanting a heart valve, for example, performing transcatheter aortic valve implantation (TAVI) or transcatheter aortic valve replacement (TAVR). However, the embodiments are not limited to these uses or to any specific clinical application.

[0056] The probe 120 includes, for example, an array of ultrasonic transducers, preferably in the form of an array of ultrasonic transducers.

[0057] An ultrasonic transducer is a transducer adapted to convert an electrical signal into an ultrasonic wave, and conversely, to convert an ultrasonic wave into an electrical signal. Depending on the type of transducer, the electrical signal may correspond to a voltage, a current, or an electrical charge.

[0058] The transducer network may include any type of ultrasonic transducer, or even several types of ultrasonic transducers.

[0059] Ultrasonic transducers can be made of a layer of single-crystal or polycrystalline piezoelectric material, for example PZT (Lead-Zirconia Titanate), or a composite structure comprising at least one layer of piezoelectric material, for example a layer of PZT including polymer-filled grooves.

[0060] Ultrasonic transducers can be microelectromechanical systems, or MEMS, implementing microelectronic production technologies. A MEMS transducer generally comprises one or more acoustic elements, each including one or more deformable membrane(s) suspended above a cavity and connected by a common electrode. In one embodiment, each deformable membrane is displaced or deformed by capacitive effect using an electrode attached to the membrane and an electrode separated by the cavity. This type of ultrasonic transducer is known by the acronym CMUT, for Capacitive Micro-machined Ultrasonic Transducer, i.e., a micro-machined ultrasonic capacitive transducer, or membrane capacitive transducer.In another embodiment, each deformable membrane is displaced or deformed by piezoelectric effect using a layer of piezoelectric material equipped with two electrodes attached to the membrane. This type of ultrasonic transducer is known by the acronym PMUT, from the English Piezoelectric Micro-machined Ultrasonic Transducer, i.e., a micro-machined piezoelectric ultrasonic transducer, or membrane piezoelectric transducer.

[0061] The problem arises of establishing a link, in particular electrical, or even optical, between the ultrasonic transducers of the ultrasonic imaging probe 120 at the distal end 100A of the sheath and the proximal end 100B of the sheath 100 where the control handle 12 is located.

[0062] Ultrasonic transducers are generally connected to an interconnection structure at the probe 120, and in particular to conductive tracks, generally metallic, of the interconnection structure. The interconnection structure extends by means of connecting (conductive) strips, for example cables, ribbons, blades, or flats, which are connected to the conductive tracks of the interconnection structure. The connecting strips extend in the axial direction X towards the proximal end 100B of the sheath 100.

[0063] A major difficulty in achieving the connection is related to the bending of the sheath 100, or at least of the flexible portion 110 of the sheath 100 which undergoes significant and opposite deformations between the inside and outside of the bending. Ideally, the connecting strips should pass through the center of the sheath 100, that is, in the internal axial lumen 104 of the sheath 100, preferably as close as possible to the axis of the sheath 100, in order to minimize stresses / deformations related to the distance from the neutral line when the sheath 100 is bent. However, since the axial lumen 104 is intended for the passage of a catheter or other elongated medical device, the connecting strips cannot pass through the axial lumen 104, and they pass around the periphery of the sheath 100. Thus, the connecting strips move away from the axis of the sheath 100, and from the neutral line, especially as the diameter of the sheath 100 increases.

[0064] When the sheath 100 is flexed, one semi-cylindrical half is subjected to elongation (extension) on the side opposite the bend, while the other half is subjected to contraction (compression) of the same magnitude. The elongation and contraction generated by the bend are greater the further one moves from the axis of the sheath 100 and the closer one moves to the plane of bend. The connecting strips passing around the periphery of the sheath 100, on the plane of bend, also undergo the elongation and contraction generated by the bend. An existing solution to prevent the connecting strips from undergoing these stresses, or at least to limit them, is to wind them around the sheath 100, for example in a substantially helical fashion, in order to distribute the areas subjected to elongation and contraction homogeneously.However, besides the potential technical difficulty in implementing this type of solution within the restrictive dimensions of the feed ducts, ranging from a few millimeters to a few tens of millimeters in outside diameter, the winding inevitably leads to lengthening the connection strips, which in turn increases electrical losses.

[0065] Furthermore, in the case of high-density transducer networks, the interconnection of the transducers is generally high-density, in small and constrained dimensions, which can amplify electrical losses and generally costs.

[0066] Figures 2A to 3D below illustrate a solution to the problem of creating a link between the ultrasonic transducers of the ultrasonic imaging probe 120 and the control handle 12, which allows the problems of elongation and contraction generated by the curvature of the sheath 100 to be managed, while limiting the length of the connection strips, thus reducing the associated electrical losses.

[0067] A solution is also sought to address the problem of elongation and contraction generated by the curvature of the sheath, even with a network of transducers with a high density of transducers and a high density of interconnections allowing individual or RCA type addressing of these transducers.

[0068] Figures 2A, 2B, and 2C are longitudinal cross-sectional views partially representing an example of a medical delivery sheath 200 according to one embodiment. Figures 2A to 2C more particularly represent the flexible portion 210 of the delivery sheath 200, or distal portion 210. Figure 2A is a view of the distal portion 210 in a straight configuration. Figure 2B is a view of the distal portion 210 in a configuration curved at approximately 90°. Figure 2C is a detail view of the distal portion 210 taken within the circle shown in Figure 2B.

[0069] When the sheath is curved, we can speak of a braced sheath in the technical field of this description.

[0070] In [Fig.2A], the axial direction X is straight, while in figures 2B and 2C, the axial direction X is bent.

[0071] The introduction sheath 200 shown in figures 2A to 2C can correspond to the sheath 100 of [Fig.1], the distal portion 210 then corresponding to the flexible portion 110 of [Fig.1].

[0072] The sheath 200 is hollow, with an internal axial lumen 204 extending along the axial direction X, between the distal end 200A and proximal end 200B of the sheath 200.

[0073] The distal portion 210 of the medical introduction sheath 200 includes an orientation coupler 211, which is adapted to impart a curvature to the distal portion 210.

[0074] The orientation coupler 211 comprises a plurality of links 212, two adjacent links cooperating with each other so as to be able to pivot about at least one axis of rotation. For example, the links 212 form a joint.

[0075] The plurality of links 212 includes in particular: - a distal link 212A at the distal end 21 IA of the coupler 211; - a proximal link 212B at the proximal end 21 IB of the coupler 211; and - intermediate links 212C between the distal link 212A and the proximal link 212B.

[0076] The links 212 are, for example, made of a material capable of forming smooth bearings between the links, for example: - a metal: for example steel, aluminium, tungsten, titanium ...; - a rigid polymer material: for example polycarbonate (PC), polymethyl methacrylate (PMMA) ...; - in ceramic material: for example alumina (Al2O3), zirconium oxide (ZrO2), silicon carbide (SiC)...

[0077] The links 212 are, for example, ball joints. A person skilled in the art may determine other types of links capable of pivoting relative to each other around at least one axis of rotation, so as to impart a curvature to the flexible portion 210 of the sheath 200.

[0078] The distal link 212A is connected to a distal ring 201. The proximal link 212B is connected to a proximal ring 202, for example, is fitted into the proximal ring 202. The rings 201 and 202 can form stiffeners. The distal ring 201 can be designated as the "brace head".

[0079] The distal ring 201 is itself fitted into a tip 203 which is fitted with the distal link 212A, so as to form a fixed distal ring / tip / distal link assembly.

[0080] In the example shown, the distal ring 201 has a diameter which narrows towards the distal end 200A of the sheath 200. Thus, the distal ring 201 comprises a cylindrical proximal portion 201B of a diameter Dl, a cylindrical distal portion 201A of a diameter D2 smaller than the diameter Dl, and a frustoconical portion 20IC connecting the portions 201A and 20IB.

[0081] In the example shown, the tip 203 has a diameter that increases towards the distal end 200A of the sheath 200. Thus, the tip 203 comprises a cylindrical proximal portion 203B of a diameter D3 (which fits with the distal link 212A), a cylindrical distal portion 203A of a diameter D4 greater than the diameter D3, and a frustoconical portion connecting the portions 203A and 203B.

[0082] The rings 201, 202 and the tip 203 are hollow, for example annular, and the links 212 are ring-shaped, or at least in a shape allowing a hollow central portion to be delimited, so that the sheath 200 retains an axial light 204, including in the distal portion 210.

[0083] The links 212 are held together by cables 205, respectively 206, or linkage cables, for example metal cables, which pass through grooves 213, respectively 214, formed on the peripheries of the links 212.

[0084] Two cables 205 constitute a first pair of cables parallel to each other in the plane of Figures 2A to 2C, while two other cables 206 constitute a second pair of cables parallel to each other in a plane perpendicular to the plane of Figures 2A to 2C. For example, the cables 205 allow the distal portion 210 to be bent in a direction perpendicular to the direction X and in a plane parallel to the plane of Figures 2A to 2C, and the cables 206 allow the distal portion 210 to be bent in a direction perpendicular to the direction X and perpendicular to the plane of Figures 2A to 2C.

[0085] For example, cables 205 and 206 each have a distal end retained in the distal link 212A, in the ring 201, or in the end piece 203.

[0086] Cables 205 and 206 preferably extend to the proximal end 200B of the sheath 200, for example to the control handle 12 visible in [Fig. 1]. Cables 205 and 206 can thus be controlled to control the pivoting of the links 212, and thus the flexing of the distal portion 210.

[0087] The distal portion 210 of the medical introduction sheath 200 further includes a sleeve 215, which is arranged around the orientation coupler 211, i.e. around the links 212.

[0088] The sleeve 215 can be fitted, being around the orientation coupler 211, into the proximal ring 202. The sleeve 215 can extend around the tip 203, for example around the proximal portion 203B of the tip 203.

[0089] The sheath 215 is made of a flexible material, so that the sheath 215 can follow the curvature of the distal portion 210. For example, the sheath 215 may be made of an elastomeric material, for example a thermoplastic elastomer (TPE), for example a polyether block amide (PEBA), for example silicone. The sheath 215 may be made of a biocompatible material, but this is not mandatory, as the sheath is not in contact with the external environment of the sheath 200, i.e., with the environment surrounding the sheath 200 or inside the sheath 200, in the lumen 204.

[0090] The sheath 215 comprises a substantially cylindrical tubular portion 216 and a peripheral portion 217 projecting from the outer wall of the tubular portion 216. The peripheral portion 217 comprises a plurality of projecting turns 219, or protrusions. The protrusions 219 project outwards in the radial direction, that is, away from the axis, so that the tubular portion 216 is contained between the protrusions 219 and the links 212.

[0091] In the example shown, the peripheral portion 217 has a helical, protruding shape that winds around and along the tubular portion 216 in the axial direction X. The protrusions 219 correspond to the turns of the helix and are thus connected to each other. The pitch of the helix may be regular or irregular.

[0092] Alternatively, the peripheral portion may comprise several projecting rings, disjointed from each other and wound around the tubular portion 216. The projecting rings are distributed, for example regularly distributed, over several circumferences of the tubular portion 216 along the axial direction X, the projecting rings forming the protrusions. In this case, the projecting turns forming the protrusions are disjoint from each other.

[0093] The sheath 200 comprises, at its distal end 200A, which is also the distal end of the distal portion 210, a forward-looking ultrasound imaging probe 220, that is, oriented from the distal end 200A of the sheath 200 in the direction of advancement of the sheath 200, as defined above. The probe 220 extends all around the axial lumen 204 on the transverse face 200C of the sheath 200, which is at the distal end 200A. The transverse face 200C is perpendicular to the axial direction X. In this example, the transverse face 200C is in the form of a ring and is all around the axial lumen 204.

[0094] The probe 220 comprises an array of several ultrasonic transducers 225 (identified in [Fig.3A]) which are positioned at least partly in a circumferential groove 203C formed in the tip 203 all around the axial lumen 204.

[0095] The transducer network is preferably a transducer matrix.

[0096] The transducer network can comprise any number of transducers at ultrasound, for example between 128 and 1024, for example, comprising several concentric rings, each containing several ultrasonic transducers. The ultrasonic transducers of the same ring can be distributed in radial sectors of the ring, as illustrated in the example in [Fig. 4] described later.

[0097] For example, the number of rings is greater than 3 and the number of transducers (radial sectors) per ring is greater than 30.

[0098] The transducers are generally connected to an interconnection structure 230 (described later in connection with Figures 3A to 3D) at the probe 220, and in particular connected to conductive tracks of the interconnection structure. The interconnection structure extends into (conductive) connection strips 231, for example cables, ribbons, blades, or flat connecting strips, connected to the conductive tracks of the interconnection structure. In the following description, the connection strips 231 are referred to as flat connecting strips 231.

[0099] The flounders 231 are, for example, each made of a flexible printed circuit board. A flexible printed circuit board consists of conductive tracks, for example made of copper, arranged on or inside a flexible insulating substrate made of a dielectric material, usually a polymer, for example polyimide.

[0100] The flounders 231 extend in the axial direction X from the probe 220 towards the proximal end 200B of the sheath 200. For example, the flounders 231 are substantially straight in the configuration of [Fig.2A] (unbent sheath).

[0101] The flounders 231 pass around the periphery of the sheath 200, in particular around, and along, the sleeve 215. For example, the flounders 231 are regularly distributed around the sleeve 215.

[0102] The flounders 231 can extend to the proximal end 200B of the sheath 200. Alternatively, the flounders 231 can be interrupted before the proximal end 200B of the sheath 200, and for example be connected to a flexible conductive ribbon which extends to the proximal end 200B, or even beyond.

[0103] The distal portion 210 of the medical introduction sheath 200 further comprises an elastic structure 218 wound around the sheath 215 and the flounders 231. The elastic structure 218 runs along several circumferences between the protrusions 219.

[0104] The elastic structure 218 is adapted, during the curvature of the distal portion 210, to absorb the elongation (extension) on one side E (side opposite to the curvature, or side of the large radius of curvature) of the sheath 200, and the contraction (compression) on the other side F (side of curvature, or side of the small radius of curvature) of the sheath 200, with the flounders 231 remaining extended in the axial direction X, i.e. without having to wrap the flounders 231 around the sheath 200, thus limiting the lengths of the flounders, and limiting the electrical losses accordingly.

[0105] As can be seen in [Fig.2C]: - on the side E opposite the curvature, the flounders 231 are substantially stretched between the protrusions 219 and the elastic structure 218 is in extension on this side E; and - on the side F of the curvature, the elastic structure 218 in compression presses the flounders 231 against the sheath 215, and in particular against the protrusions 219 and against the tubular portion 216 between the protrusions 219.

[0106] Thus, the protrusions 219, by the profile they form with the tubular portion 216, combined with the elastic structure 218, ensure that the flounders 231 are all substantially the same length. A person skilled in the art can determine the thickness, and possibly the width in the X direction, of the protrusions 219 so as to achieve this effect.

[0107] The elastic structure 218 is made of a material sufficiently flexible to be wrapped around the flounders 231, for example of rubber, an elastomer, a polymer.

[0108] The cross-section of the elastic structure 218 is, for example, circular, oval, rectangular, or polygonal. The elastic structure 218 may also consist of a rigid wire structured in the form of a spring.

[0109] It should be noted that the elastic structure 218 remains only slightly deformed when transitioning from a straight configuration ([Fig. 2A]) to a curved configuration ([Fig. 2B]). Indeed, the elastic structure 218 moves away from the center of curvature without being significantly deformed. The elasticity of the structure 218, as well as its cross-section, should preferably be adapted by a person skilled in the art to absorb the deformations of the flounders 231.

[0110] In the example shown, the elastic structure 218, as well as the peripheral portion 217, is in the form of a helix, with several turns, traveling around and along the sleeve 215 in the axial direction X. The turns of the elastic structure 218 travel between the protrusions 219 of the peripheral portion 217.

[0111] Alternatively, the elastic structure, and in this case the peripheral portion, can be in the form of several disjoint rings. In this case, the turns of the elastic structure are disjoint. The rings of the elastic structure are positioned between the protruding rings of the peripheral portion.

[0112] The turns of the elastic structure 218 and the turns of the peripheral portion 217, whether joined or disjoint in the form of rings, can be distributed at regular intervals in the direction X.

[0113] Alternatively, the turns of the elastic structure 218 and the turns of the peripheral portion 217, whether joined or disjointed in the form of rings, can be distributed irregularly, for example with an increased density around the center C of the distal portion 210, where the curvature reaches its maximum.

[0114] The number of turns of the elastic structure 218 is, for example, between 5 and 150. More generally, a person skilled in the art will be able to determine the number of turns based on the angle of flexion of the distal portion 210, the outside diameter of the sheath 200, the radius of curvature, and the absorption capacity of the protrusions 219. A person skilled in the art may choose to distribute the elastic structure 218 over substantially the entire length of the sheath 200 and not only around the flexible portion 210, which may increase the number of turns.

[0115] An outer envelope 207 in the form of a flexible sheath encloses all the elements described above, and in particular the flounders 231, the elastic structure 218, the sleeve 215, the rings 201, 202, the end piece 203, and the cables 205, 206.

[0116] This outer envelope 207 may include a distal end 207A positioned on the probe 220, and, in this case, the outer envelope 207 is preferably transparent to ultrasonic waves, for example is made of silicone.

[0117] The outer casing 207 is preferably biocompatible, for example made of silicone, for example PEBA, or coated with a biocompatible material, for example coated with parylene.

[0118] An inner sleeve (not visible in Figures 2A to 2C) may be provided around the distal portion 201A of the distal ring 201, the distal portion 203A of the tip 203 then being around this inner sleeve. The inner sleeve is, for example, made of silicone.

[0119] By way of non-limiting illustration, the largest diameter of the axial lumen 204, i.e. the internal diameter of the distal portion 210 of the sheath 200, is between 2.5 and 25 mm, and the overall diameter of the distal portion 210 of the sheath 200, i.e. the external diameter of the outer envelope 207, is between 7 and 30 mm.

[0120] Fig. 3A and Fig. 3B are three-dimensional views of the medical delivery sheath 200 of Figures 2A to 2C. Fig. 3C and Fig. 3D are views representing the interconnection structure 230 of the medical delivery sheath of Figures 3A and 3B. Fig. 3A shows in three dimensions the flexible portion 210 without the outer sheath, while Fig. 3B shows in three dimensions the flexible portion 210 with the outer sheath 207. Fig. 3C shows in three dimensions a detail of the interconnection structure 230 deployed perpendicular to the X direction. Fig. 3D shows another detail of the interconnection structure 230 in a direction parallel to the X direction.

[0121] The introduction sheath shown in Figures 3A and 3B corresponds to the sheath 200 of Figures 2A to 2C, the flexible portion corresponding to the distal portion 210 of Figures 2A to 2C.

[0122] In the example of [Fig.3A], the ultrasonic transducers 225 of the ultrasonic imaging probe 220 are piezoelectric material-based transducers and are formed by several annular layers extending one over the other around the axial lumen 204: - a layer of piezoelectric material 221, or piezoelectric layer 221, cut through its entire thickness to form several sectors of the piezoelectric layer, or piezoelectric sectors: the piezoelectric layer can be metallized on each of its inner and outer faces to form an outer metallic layer and an inner metallic layer, the cutting of the piezoelectric layer including the cutting of the outer and inner metallic layers, each piezoelectric sector thus comprising an outer electrode, corresponding to a sector of the cut outer metallic layer, and an inner electrode corresponding to a sector of the cut inner metallic layer; and - an impedance matching layer 222 on the piezoelectric layer: the impedance matching layer is cut, usually at the same time as the piezoelectric layer, to form several sectors of the impedance matching layer, or impedance matching sectors, each impedance matching sector being positioned opposite a piezoelectric sector, and for example in contact with this piezoelectric sector, forming a stack.

[0123] Instead of a single piezoelectric layer, it may be a stack of piezoelectric layers.

[0124] A stack of an impedance matching sector on a piezoelectric sector makes it possible to form all or part of an ultrasonic transducer 225. The stacks of impedance matching and piezoelectric sectors are generally separated from each other by slots, or kerfs.

[0125] The sectors can be annular and radial, so that the transducer network comprises rings each comprising several transducers 225 distributed along the circumference of the ring.

[0126] An annular layer of an acoustic attenuation material 223, or "backing" layer, is positioned under the piezoelectric layer 221. The backing layer 223 is not, for example, cut into sectors.

[0127] The interconnection structure 230 includes an annular portion 232 taken between the backing layer 223 and the piezoelectric layer 221, and connected to the flounders 231.

[0128] The flounders 231 are folded over the tip 203 and the sheath 215.

[0129] As illustrated in Figures 3C and 3D, the annular portion 232 comprises electrical contact pads 234, each connected to a metal track 236. Generally, one contact pad 234 is connected to a transducer 225. The metal tracks 236 extend into the flanges 231. The contact pads 234 and the metal tracks 236 are, for example, dedicated to the signals from the transducers. The metal tracks 236 are insulated from each other and arranged in, and / or on, an insulating support 237, or dielectric support. The dielectric support 237 is, for example, in the form of a film of polymer material, preferably flexible, for example, polyimide. Several other materials can be suitable for a flexible dielectric support, for example, polyester, polyethylene polynaphthalate, or polyetherimide. The 236 metal tracks can advantageously be made of a malleable material, for example gold or copper.Indeed, the metal tracks 236 are folded, along with the flats 231. The interconnection structure 230 further includes internal strips 233, or tabs 233. Each tab 233 includes an electrical contact pad 235, which is, for example, a ground pad.

[0130] The legs 233 are folded inside the sheath 200, i.e. in the axial lumen 204, for example in contact with the inner wall of the distal ring 201.

[0131] The annular portion 232 is connected to the flounders 231 and the legs 233, and is included between the flounders 231 and the legs 233 which extend radially in two opposite directions from the annular portion 232.

[0132] For example, the number of legs 233 is equal to the number of flounders 231.

[0133] According to one embodiment, the interconnection structure 230 comprises sixteen flats 231, and eighteen metal tracks 236 per flat (two for ground and sixteen connected to the electrodes of the transducer elements of the ultrasonic probe 220), which allows 256 transducers to be electrically connected independently.

[0134] The metal tracks 236, for example, have a width of approximately 20 µm and are spaced approximately 50 µm apart, with a flange width of approximately 2 mm. Thinner and more closely spaced metal tracks can be made. For example, the metal tracks 236 can have a width of less than 15 µm, for example approximately 5 µm, and a spacing of less than 25 µm, for example approximately 5 µm. This can allow more transducers to be electrically connected, for example, more than the 256 transducers shown in the example of the interconnect structure 230.

[0135] According to another solution for electrically connecting more transducers, which can be combined with the previous solution, the interconnection structure 230 can comprise several interconnection layers, on and / or in the dielectric support 237, each interconnection layer being similar to that described above, and the metallic tracks of the different interconnection layers being connected to each other by vertical connections called "vias". This makes it possible to interconnect a very high number of transducers, typically more than 256, for example 512 transducers for two interconnection layers similar to that described above, 768 transducers for three interconnection layers similar to that described above, 1024 transducers for four interconnection layers similar to that described above...

[0136] The interconnection structure 230 can be a flexible printed circuit board, or "FPCB".

[0137] Fig. 3B shows that the outer envelope 207 can be extended over the probe 220 (portion 207A), as described above, and that furthermore it can be extended inside the axial lumen 204, in contact with the inner wall of the sheath 200.

[0138] Fig. 4 is a schematic view representing an example of an ultrasonic imaging probe 420 of a medical introduction sheath according to one embodiment.

[0139] The ultrasound imaging probe 420 can correspond to the ultrasound imaging probe 220 in Figures 2A, 2B and 3A. The medical introduction sheath can correspond to the sheath 200 in Figures 2A to 2C.

[0140] In the ultrasonic imaging probe 420, the transducer array comprises several concentric rings around the axial lumen 204, each ring comprising several transducers 425. In this example, the transducer array comprises the same number of transducers for all rings, a substantially equal surface area for all transducers, and a substantially constant spacing between the transducers. In the example shown, the transducer array comprises eight rings, with 128 transducers per ring, forming an array of 1024 transducers.

[0141] In the ultrasonic imaging probe 420, a first electrode of each transducer 425 is individually connected to a conductive track of the interconnecting structure 230 and a second electrode is connected to a common ground with the other second electrodes of the other transducers of the probe 420, so that each transducer can be driven individually.

[0142] As an alternative, the first electrodes of the transducers 425 in the same angular sector can be connected together, and the second electrodes of the transducers in the same ring can also be connected together. This results in a radius-angle controllable transducer array whose control principle is similar to row-column addressable arrays (or RCA arrays). This alternative has the advantage of reducing the number of connections required for an equivalent number of transducers, or conversely, increasing the number of transducers for an equivalent number of connections. In the example of [Fig. 4], the probe 420 would then require, for example, 8 plus 128, or 136 connections instead of 1024.

[0143] The described embodiments demonstrate that a medical delivery sheath can be provided, adapted to receive a catheter or any other elongated medical device and incorporating an imaging function. Furthermore, the medical delivery sheath is orientable while allowing for electrical connection of the ultrasound transducers.

[0144] The medical delivery sheath according to the embodiments can find applications in the field of cardiac disease treatment, for example, for implanting a pacemaker, for performing radiofrequency ablation (RF ablation), or for replacing or implanting a heart valve, for example, performing transcatheter aortic valve implantation (TAVI) or transcatheter aortic valve replacement (TAVR), the sheath generally being used in conjunction with a catheter or other elongated medical device positioned in the axial lumen of the sheath. Other applications can be envisaged, which utilize the sheath medical introduction equipped with an ultrasound imaging probe according to the embodiments, in association with an elongated medical device of the catheter type.

[0145] Various embodiments and variations have been described. A person skilled in the art will understand that certain features of these various embodiments and variations could be combined, and other variations will become apparent to a person skilled in the art.

[0146] Finally, the practical implementation of the embodiments and variants described is within the reach of a person skilled in the art, based on the functional indications given above.

Claims

Demands

1. Medical introduction sheath (100; 200) extending along an axial direction (X) between a distal end (100A; 200A) and a proximal end (100B; 200B) opposite the distal end, the medical introduction sheath having an internal axial lumen (104; 204) between said distal end and said proximal end, and a flexible portion (110; 210) extending to said distal end, the flexible portion comprising: - an ultrasound imaging probe (120; 220; 420) comprising several ultrasound transducers (225; 425) distributed in an array on a transverse face (200C) of the medical introduction sheath at the distal end (200A), around the axial lumen (104; 204); - an orientation coupler (211) adapted to impart a curvature to the flexible portion (210);- a sheath (215) arranged around the orientation coupler (211), said sheath comprising a tubular portion (216) and a protruding peripheral portion (217) wound in several projecting turns (219) around the tubular portion (216), along the axial direction (X), the tubular portion (216) being contained between the peripheral portion (217) and the orientation coupler (211); and - connecting strips (231) extending from the ultrasonic transducers (225; 425) in the axial direction (X) towards the proximal end (200B) and distributed around the sheath (215); and - an elastic structure (218) wound in several turns around the sheath (215) and the connecting strips (231), the elastic structure (218) running between the projecting turns (219).

2. Medical introduction sheath (200) according to claim 1, wherein the peripheral portion (217) has a helical shape, the protruding turns (219) corresponding to the turns of the helix, the elastic structure (218) also having a helical shape running between the protruding turns (219).

3. A medical delivery sheath according to claim 1, wherein the projecting turns of the peripheral portion are projecting rings disjoint from each other, and distributed, for example regularly distributed, over several circumferences of the tubular portion along the axial direction, the turns of the elastic structure being also rings that are disjoint from each other and positioned between the protruding rings.

4. Medical introduction sheath (200) according to any one of claims 1 to 3, wherein the pitch between the turns of the elastic structure (218) is substantially equal to the pitch between the protruding turns (219) of the peripheral portion (217), the turns of the elastic structure being distributed regularly along the axial direction (X).

5. Medical introduction sheath according to any one of claims 1 to 3, wherein the pitch between the turns of the elastic structure is substantially equal to the pitch between the protruding turns of the peripheral portion, the turns of the elastic structure being distributed irregularly along the axial direction (X), for example with a greater density around a center (C) of the flexible portion (210).

6. Medical introduction sheath according to any one of claims 1 to 5, wherein the axial lumen is dimensioned to receive a catheter in a sliding and / or rotating manner.

7. Medical introduction sheath (200) according to any one of claims 1 to 6, wherein the orientation coupler (211) comprises links (212), for example ball joints, two adjacent links cooperating with each other so as to be able to pivot about at least one axis of rotation.

8. Medical introduction sheath (200) according to claim 7, wherein the orientation coupler (211) comprises linkage cables (205, 206) connected to the links (212) so as to hold the links against each other, and to control the pivoting of the links (212), and thus a bending of the flexible portion (210).

9. Medical introduction sheath (200) according to any one of claims 1 to 8, wherein the ultrasonic transducers (225; 425) of the ultrasonic probe (220; 420) are distributed in several concentric rings around the axial lumen (204), each ring comprising several transducers distributed in radial sectors along said ring, for example the number of rings is greater than 3 and the number of transducers per ring is greater than 30.

10. Medical introduction sheath (200) according to any one of claims 1 to 9, wherein the ultrasonic transducers (225) are piezoelectric transducers and are formed by several annular layers extending one over the other around the axial lumen (204), said annular layers comprising: - a piezoelectric layer (221) metallized on each of its inner and outer faces, and divided into several piezoelectric sectors, for example annular and radial sectors; - an impedance matching layer (222) on the piezoelectric layer (221) and divided into several impedance matching sectors, each impedance matching sector being positioned opposite a piezoelectric sector; and - an acoustic attenuation layer (223), below the piezoelectric layer (221).

11. Medical delivery sheath according to claim 10, further comprising an interconnection structure (230) including the connection strips (231), the interconnection structure further comprising an annular portion (232) disposed between the acoustic attenuation layer (223) and the piezoelectric layer (221), said annular portion comprising metallic tracks (236) connected to the ultrasonic transducers (225) and extending into the connection strips (231).

12. Medical introduction sheath (200) according to any one of claims 1 to 11, further comprising an annular tip (203) at the distal end (200A), said tip being connected to the orientation coupler (211), for example to a distal link (212A) of said orientation coupler, the ultrasonic transducers (225) being arranged in a circumferential groove (203C) of said tip all around the axial lumen (204).

13. Medical delivery sheath according to any one of claims 1 to 12, further comprising an outer cover (207) around the connecting bands (231), the sheath (215) and the elastic structure (218), the outer cover being for example made of a biocompatible material.

14. Intracorporeal exploration and intervention device (10) comprising a medical introduction sheath (100; 200) according to any one of claims 1 to 13.

15. Device (10) according to claim 14, further comprising a catheter configured to be introduced into the axial lumen (104; 204) of the medical introduction sheath (100; 200).

16. Device (10) according to claim 14 or 15, further comprising, at the proximal end (100B; 200B), a control handle (12) adapted to control a flexion of the flexed portion sand (110; 210).

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