CN114401762A

CN114401762A - Barbed microcatheter with fluid exit opening for infusion of therapeutic fluid into tissue and methods of making and using same

Info

Publication number: CN114401762A
Application number: CN202080064257.7A
Authority: CN
Inventors: F·R·小齐乔基; S·恰罗卡
Original assignee: Aixikang Co ltd
Current assignee: Aixikang Co ltd
Priority date: 2019-09-13
Filing date: 2020-09-02
Publication date: 2022-04-26
Also published as: JP2022548241A; BR112022004499A2; AU2020344233A1; EP4028101A1; MX2022003038A; AU2020344233B2; KR20220064381A; WO2021048705A1

Abstract

The present invention provides a microcatheter (100) for delivering therapeutic fluids to a patient and methods of making and using the same. The barbed microcatheter comprises: a hollow tube (102) having an elongate lumen extending between a proximal end and a distal end of the hollow tube; a plurality of barbs (108) projecting from the hollow tube; and a plurality of fluid outlet openings (110) formed in the hollow tube, the plurality of fluid outlet openings being in fluid communication with the elongated lumen. The fluid outlet openings are evenly spaced from each other along the length of the hollow tube. An anchor (112) is secured to the proximal end of the hollow tube and a surgical needle (114) is secured to the distal end of the hollow tube.

Description

Barbed microcatheter with fluid exit opening for infusion of therapeutic fluid into tissue and methods of making and using same

Cross Reference to Related Applications

This patent application claims priority from U.S. patent application serial No. 16/570,017 filed on 13.9.2019 and U.S. patent application serial No. 16/570,028 filed on 13.9.2019.

Background

Technical Field

The present patent application relates generally to medical devices and, more particularly, to catheters that are implanted in patients and methods of making the same.

Description of the Related Art

Many medical protocols involve the infusion of therapeutic fluids into selected regions of a patient's body. The types of therapeutic fluids that physicians commonly employ to treat patients include anesthetics, antibiotics, antimicrobials, chemotherapeutic agents, and growth factors.

Historically, therapeutic fluids have been delivered to patients using catheters that are temporarily implanted in the patient for delivery of the therapeutic fluid during a treatment session. At the end of the treatment session, the catheter is removed from the patient. Unfortunately, catheter removal often results in wound dehiscence and pain to the patient.

In many cases, linear catheters are used to treat patients. Sutures or other fixation devices (e.g., staples) are often used to hold the linear catheter in place, which can complicate the procedure, introduce additional foreign matter into the patient, and compromise catheter performance by impeding the flow of therapeutic fluid through the catheter.

In some cases, it is necessary to use a non-linear catheter, rather than a linear catheter, which is arranged inside the patient in a complex three-dimensional configuration. For example, a non-linear catheter having a three-dimensional configuration may be used to extend around an object located inside the body, such as a tumor, an artificial joint, or a complex surgical wound. Due to their non-linear shape, medical personnel often have difficulty removing the non-linear catheter from the patient.

Catheters implanted in patients come in many different sizes. In some cases, medical personnel need to use a thin catheter (also referred to as a microcatheter) to deliver the therapeutic fluid to the patient. Forming fluid channels in a thin conduit can be extremely challenging because of the precise tolerances required to maintain uniform fluid flow over the length of the thin conduit.

When creating fluid passageways in larger sized catheters, sharp hollow stainless steel tubes can be used to perforate material from the walls of the catheter. As the size of catheters decreases, this approach becomes more challenging because of the limitations in the size of sharp hollow stainless steel tubes that can be used to create fluid passageways in the catheters. Even if very thin steel tubing is available to form the fluid channel, the material that is perforated from the wall of the catheter to form the fluid channel tends to get stuck inside the lumen of the catheter and must be removed from the lumen. Removing the perforated material presents its own set of challenges.

The fluid channels may be formed in the catheter tubing using a laser for forming the channels. However, it is difficult to precisely control the power level of the laser, so the laser-formed fluid channel is typically drilled all the way through the catheter tubing, rather than remaining on only one side of the catheter tubing. The laser also vaporizes and ablates materials that may re-condense on or inside the catheter tube. Furthermore, the chemical structure of the ablated/vaporized material will typically change due to the intense heat of the laser, such that the laser drilled catheter will no longer be biocompatible or easily quantified for design control and regulatory registration purposes of the medical device. In addition, lasers tend to locally heat the material and alter the structure and molecular orientation of the conduit tubing material, which results in conduits having poor mechanical properties. Finally, lasers providing sufficient power and spot sizes less than 30um can be very expensive, which increases manufacturing costs.

In view of the above-described deficiencies, there remains a need for systems, devices, and methods for safely, efficiently, economically, and reliably mass producing microcatheters having fluid outlet openings.

There is also a need for systems, devices, and methods for manufacturing microcatheters having fluid outlet openings of different sizes along the length of the microcatheter in order to achieve uniform fluid delivery.

Further, there remains a need for microcatheters having fluid outlet openings of different sizes, including smaller fluid outlet openings located closer to the fluid source and larger fluid outlet openings located further from the fluid source.

In addition, there remains a need for systems, devices, and methods for fabricating microcatheters having fluid outlet openings without altering the molecular structure, characteristics, and/or chemistry of the materials used to fabricate the microcatheters.

Furthermore, there remains a need for automated systems and methods for safely, efficiently, economically and reliably mass producing microcatheters having thin fluid outlet openings for local delivery of therapeutic fluids to a patient.

There is also a need for an absorbable barbed microcatheter with fluid outlet openings for delivering therapeutic fluids to a patient whereby the microcatheter may be absorbed by the patient's body and need not be removed from the patient.

Disclosure of Invention

In one embodiment, a microcatheter having a fluid outlet opening for delivering a therapeutic fluid to a patient is made of a bioabsorbable material, which eliminates the need to remove the catheter at the end of a treatment session.

In one embodiment, a microcatheter having a fluid outlet opening for delivery of therapeutic fluid incorporates a continuous fixation method such as barbs, which allows medical personnel (e.g., a surgeon) to precisely place the microcatheter inside the patient without the need for additional fixation mechanisms such as sutures or staples. Such catheters (e.g., barbed microcatheters) can be easily placed perioperatively in any desired configuration that is relatively simple and minimizes additional procedural time.

In one embodiment, a microcatheter having a fluid outlet opening for delivering a therapeutic fluid preferably includes an elongated central lumen extending along the length of the catheter. The microcatheter preferably includes a perforated or cut anchoring barb for holding the catheter in place inside the patient.

In one embodiment, a barbed microcatheter for delivering fluid to a patient preferably comprises: a hollow tube having a proximal end, a distal end, and an elongate lumen extending between the proximal and distal ends of the hollow tube; a barb projecting outwardly from the hollow tube; and a plurality of fluid outlet openings formed in the hollow tube, the plurality of fluid outlet openings being in fluid communication with the elongated lumen of the hollow tube.

In one embodiment, the fluid outlet openings are spaced apart from each other between the proximal and distal ends of the hollow tube.

In one embodiment, the fluid outlet openings may be evenly spaced apart from each other between the proximal and distal ends of the hollow tube.

In one embodiment, each of the fluid outlet openings may be the same size.

In one embodiment, two or more of the fluid outlet openings may have different sizes. In one embodiment, the size of the fluid outlet opening may gradually increase in size between the end of the hollow tube closer to the fluid source and the end of the hollow tube further from the fluid source.

In one embodiment, the fluid outlet opening is a circular hole.

In one embodiment, the fluid outlet opening is an elongated slit. In one embodiment, the hollow tube has a longitudinal axis extending between the proximal and distal ends of the hollow tube, and the elongated slit has a length extending along a common axis parallel to the longitudinal axis of the hollow tube.

In one embodiment, the hollow tube preferably has an outer surface and an inner surface surrounding the elongated lumen. In one embodiment, a fluid outlet opening is formed in the hollow tube and extends from an outer surface of the hollow tube to an inner surface of the hollow tube for fluid communication with the elongated lumen.

In one embodiment, the inner surface of the hollow tube preferably defines an inner cross-sectional diameter of the hollow tube and the outer surface of the cylindrical wall preferably defines an outer cross-sectional diameter of the hollow tube that is about 2 times the inner cross-sectional diameter of the hollow tube.

In one embodiment, the hollow tube has a wall thickness of about 0.125mm, an outer cross-sectional diameter of the hollow tube is about 0.50mm, and an inner cross-sectional diameter of the hollow tube is about 0.25 mm.

In one embodiment, the barbed microcatheter is advantageously made of an absorbable biocompatible polymer so that the barbed microcatheter will be absorbed and not have to be removed from the patient at the end of the treatment period.

In one embodiment, a barbed microcatheter for delivering fluid to tissue advantageously comprises: a hollow tube having a proximal end, a distal end, and an elongated lumen disposed inside the hollow tube extending between the proximal and distal ends of the hollow tube; a barb projecting outwardly from an outer surface of the hollow tube; and a plurality of fluid outlet openings formed in the outer surface of the hollow tube, the plurality of fluid outlet openings in fluid communication with the elongated lumen of the hollow tube. In one embodiment, the fluid outlet openings are evenly spaced from each other between the proximal and distal ends of the hollow tube.

In one embodiment, each of the fluid outlet openings has the same size. In one embodiment, two or more of the fluid outlet openings have different sizes. In one embodiment, the fluid outlet opening has a shape selected from the group consisting of a circular hole and an elongated slit.

In one embodiment, the elongate lumen of the hollow tube defines a cross-sectional diameter of about 0.25mm, and the outer surface of the hollow tube defines a cross-sectional diameter of about 0.50 mm.

In one embodiment, the anchor is fixed to the proximal end of the hollow tube.

In one embodiment, a surgical needle, such as a curved needle, is secured to the distal end of the hollow tube.

In one embodiment, a barbed microcatheter for delivering a therapeutic fluid to tissue preferably comprises: a hollow tube having a proximal end, a distal end, and an elongated lumen disposed inside the hollow tube extending between the proximal and distal ends of the hollow tube; a plurality of barbs projecting outwardly from the outer surface of the hollow tube; and a plurality of fluid outlet openings formed in the outer surface of the hollow tube, the plurality of fluid outlet openings being in fluid communication with the elongate lumen of the hollow tube, whereby the fluid outlet openings are evenly spaced apart from each other between the proximal and distal ends of the hollow tube.

In one embodiment, the barbed microcatheter preferably comprises: an anchor secured to the proximal end of the hollow tube; and a surgical needle secured to the distal end of the hollow tube.

In one embodiment, the barbed microcatheter preferably comprises two or more fluid outlet openings having different sizes, including a first fluid outlet opening having a first size positioned adjacent the anchor and a second fluid outlet opening having a second size positioned adjacent the surgical needle, the second size being smaller than the first size of the first fluid outlet opening.

Infections associated with orthopedic implants can be catastrophic to the patient, often leading to serious consequences, including re-surgery, amputation, or death. Direct delivery of local antibiotics to the site of infection in elevated doses, which would be dangerous if delivered systemically, but safe when delivered locally, can be accomplished using the microcatheters disclosed herein.

Inoperable tumors often make limited patient choice. Delivery of large doses of chemotherapeutic or immunotherapy (i.e., modifying T cells) directly to tumors may provide unprecedented benefits. The bioabsorbable microcatheters disclosed herein can be used to provide localized delivery of this type of therapeutic fluid.

Postoperative pain management of opioids is often undesirable for a variety of reasons, including risk of addiction, severe constipation, and cognitive impairment. The use of the microcatheter disclosed herein to deliver local anesthetic directly to the wound site preferably provides a mechanism for reducing opioid use while minimizing patient pain and distress.

In one embodiment, the barbed microcatheter may be coated and/or impregnated with an antimicrobial agent for preventing bacterial colonization. In one embodiment, the preferred antimicrobial agent is triclosan. In one embodiment, the triclosan antimicrobial agent may be applied to a barbed microcatheter, such as a polymeric barbed microcatheter made from polydioxanone or polycaprolactone, using a vapor process. In one embodiment, antimicrobial agents for use with barbed microcatheters may include, but are not limited to, triclosan, chlorhexidine, povidone-iodine, and/or silver compounds.

In one embodiment, a method of manufacturing a barbed microcatheter preferably includes forming a microcatheter blank (e.g., a polymeric tubing) while forming a fluid outlet opening (e.g., a fluid discharge channel), or alternatively as a first pre-requisite step of forming the fluid outlet opening. In one embodiment, the microcatheter blank may be formed and reinforced using methods well known in the art of polymer extrusion and polymer fiber drawing. In one embodiment, the microcatheter blank can be flattened to varying degrees to create lateral flattened regions that can be used to form barbs projecting from the hollow tube.

In one embodiment, the sides of the microcatheter blank can be flattened and the flat sides sealed using thermal or ultrasonic energy. The cross-sectional shape of the microcatheter blank having flat sides can be heat set prior to or during the barb forming step to produce a microcatheter having an oval cross-section. In one embodiment, the microcatheter blank may be insulated and allowed to spring back to a predominantly circular cross-section after the barb is formed.

In one embodiment, the fluid outlet opening may be formed simultaneously with any of the manufacturing steps disclosed herein, or may be completed in one or more separate steps as described herein.

In one embodiment, the barbed microcatheter disclosed herein is preferably capable of controlled and uniform distribution of therapeutic fluid from fluid outlet openings (e.g., holes, slits) located along the length of the hollow tube of the barbed microcatheter. In one embodiment, the fluid outlet opening/slit is formed in the top side of the hollow tube of the barbed microcatheter. In one embodiment, the lower side of the hollow tube is free of fluid outlet openings/slits.

In one embodiment, the size of the cross-sectional area of the fluid outlet opening may increase with increasing distance from the fluid source. In one embodiment, the fluid outlet opening closer to the fluid source may be smaller, and the fluid outlet opening further from the fluid source may be larger. The size of the fluid outlet opening may gradually increase along the length of the barbed microcatheter.

In one embodiment, the fluid outlet opening formed in the hollow tube of the barbed microcatheter may comprise an elongated slit. In one embodiment, the elongated slit may be substantially closed at a lower fluid pressure level (e.g., zero fluid pressure), however the elongated slit preferably opens upon exposure to a higher fluid pressure level, which may be generated by a syringe or fluid pump. The use of an elongated slit that opens when exposed to higher pressure levels preferably enables the entire length of the microcatheter to be loaded first with therapeutic fluid at lower fluid pressure levels. Later, when a higher fluid pressure level has been reached, the elongate fluid outlet slit will open for release of the therapeutic fluid from the elongate fluid outlet slit.

In one embodiment, a barbed microcatheter may have an anchor secured to one end and a needle (e.g., a curved needle) secured to the opposite end. In one embodiment, the anchor is secured to the proximal or posterior end of the barbed microcatheter, while the needle is secured to the distal or anterior end of the barbed microcatheter. In one embodiment, anchoring devices such as loops or reverse oriented barbs may be used. In one embodiment, double-armed and annular barbed symmetric catheters can also be manufactured.

In one embodiment, the barbed microcatheter may have fluid outlet openings/holes with the same size. In one embodiment, the barbed microcatheter may have fluid outlet openings/holes with various sizes.

In one embodiment, the barbed microcatheter may have fluid outlet slits with the same length. In one embodiment, the barbed microcatheter may have fluid outlet slits with various lengths.

In one embodiment, a needle is used to form a fluid outlet opening in a hollow tube of a barbed microcatheter. In one embodiment, the diameter of the respective needle may vary along the length of the microcatheter to vary the diameter of the respective fluid outlet opening.

In one embodiment, the forming die may be configured to include the barbed microcatheter after the initial forming step and to hold the barbed microcatheter in a set position during the stamping operation to form the one or more fluid outlet openings. In one embodiment, a fluid outlet opening die may be used to simultaneously form a barbed microcatheter when punching a fluid outlet opening.

In one embodiment, the forming die preferably has an embedded punch pin positioned along the length of the barbed microcatheter included in the forming die. The insertion depth of the respective piercing needles may be varied along the length of the forming die to control the size (i.e., diameter) of the fluid outlet openings. In one embodiment, the farther the tapered point of the needle is inserted into the die, the larger the size of the fluid outlet opening formed in the hollow tube of the barbed microcatheter.

In one embodiment, the punch pin is not permanently attached to the die, but rather can be moved into the die cavity after the microcatheter (or microcatheter blank) has been inserted into the die. In one embodiment, the needles used to form the fluid outlet openings may all be articulated together, moved together into and out of the die cavity, or they may be moved separately into and out of the die.

In one embodiment, systems, devices, and methods of manufacturing barbed microcatheters may include using one or more cutting blades to cut slits in a hollow tube to form fluid outlet slits. In one embodiment, the cutting blades may be attached to at least half of the die, or they may be slid into and out of the die cavity simultaneously or separately. In one embodiment, the depth of insertion of the cutting blade into the die may be controlled to produce elongated slits of varying lengths. Forming an elongated slit in the hollow tube of the microcatheter will have minimal effect on the tensile strength of the microcatheter. In one embodiment, the elongated slit preferably provides a mechanism for controlling the flow rate of the fluid, whereby the slit remains closed at low fluid pressure levels and opens at progressively higher fluid pressure levels for releasing the fluid.

In one embodiment, a system, device, and method of forming an elongated slit in a hollow tube of a microcatheter may involve inserting a cutting edge of a cutting blade into an outer wall of the hollow tube of the microcatheter and moving the cutting edge relative to the hollow tube for forming the elongated slit in the hollow tube. The cutting blade may articulate in two axes, or the cutting blade may be configured to move up and down while maintaining the die of the microcatheter in translation horizontally relative to the cutting blade.

In one embodiment, one or more cutting blades may be used to form barbs on the sides of the microcatheter. In one embodiment, the barbs extending longitudinally, orthogonally, or at any angle between the longitudinal and orthogonal orientations may be formed using a cutting blade. The cross-hatching or "x-pattern" may also be created by multiple passes of the cutting blade or through the use of a specially shaped cutting blade.

In other embodiments, laser and/or electron beams may be used to form barbs of barbed microcatheters.

In one embodiment, a method of manufacturing a barbed microcatheter with a fluid outlet opening preferably includes compressing a first side and a second side of a polymer blank to form a barbed microcatheter blank including a first flat region extending along the first side of the barbed microcatheter blank, a second flat region extending along the second side of the barbed microcatheter blank, and a hollow tube having an elongated lumen located between the first flat region and the second flat region.

In one embodiment, the method of making a barbed microcatheter with a fluid outlet opening may include removing material from the first and second flat regions of the barbed microcatheter blank to form barbs projecting outwardly from opposite sides of the hollow tube.

In one embodiment, the method of making a barbed microcatheter having a fluid outlet opening may comprise forming a fluid outlet opening in the wall of the hollow tube, the fluid outlet opening being in fluid communication with the elongated lumen of the hollow tube.

In one embodiment, the method of making a barbed microcatheter having a fluid outlet opening may comprise compressing the proximal end of the polymeric blank to form a tissue anchor connected to the proximal end of the hollow tube and securing the needle to the distal end of the hollow tube.

In one embodiment, at least one cutting element is used to form a fluid outlet opening in the wall of the hollow tube.

In one embodiment, the step of forming the fluid outlet opening may comprise forming a first fluid outlet opening having a first size in the wall of the hollow tube, and forming a second fluid outlet opening having a second size in the wall of the hollow tube, the second size being larger than the first size of the first fluid outlet opening.

In one embodiment, the step of forming the fluid outlet opening may comprise forming a series of progressively larger fluid outlet openings in the wall of the hollow tube.

In one embodiment, the fluid outlet opening may be formed simultaneously during the step of forming the fluid outlet opening.

In one embodiment, the fluid outlet openings are formed independently of each other and at different times during the step of forming the fluid outlet openings.

In one embodiment, the tissue anchor connected to the proximal end of the hollow tube preferably comprises a flat tab having a length and a width.

In one embodiment, the step of compressing the first side and the second side of the polymer blank may include placing the polymer blank into a press die having an upper press die portion overlying the polymer blank and a lower press die portion opposite and below the polymer blank. In one embodiment, the pressing dies are preferably moved to a closed position for compressing the upper and lower surfaces of the first and second sides of the polymeric blank for forming the first and second flat regions and the hollow tube.

In one embodiment, the upper press die section preferably comprises a plurality of cutting elements protruding from the underside of the upper press die section. In one embodiment, the cutting element engages the hollow tube for forming the fluid outlet opening in the hollow tube when the press die is in the closed position.

In one embodiment, the removing material step preferably includes cutting the first and second flat regions of the barbed microcatheter blank to form barbs projecting outwardly from opposite sides of the hollow tube.

In one embodiment, the cutting step may comprise: placing a barbed microcatheter blank comprising a first flat region and a second flat region and a hollow tube into a cutting die having an upper cutting die portion and a lower cutting die portion opposite the upper cutting die portion; and moving the cutting die to the closed position for cutting the first and second flat regions of the barbed microcatheter blank for forming barbs projecting outwardly from opposite sides of the hollow tube.

In one embodiment, the upper cutting die section preferably comprises a plurality of cutting elements protruding from the underside of the upper cutting die section. In one embodiment, the cutting element engages the hollow tube for forming the fluid outlet opening in the hollow tube when the cutting die is in the closed position.

In one embodiment, a compression roller may be used on the polymeric blank to compress the upper and lower surfaces of the first and second sides of the polymeric blank for forming the first and second flat regions of the barbed microcatheter blank and the hollow tube.

In one embodiment, a method of manufacturing a barbed microcatheter with a fluid outlet opening advantageously includes obtaining a barbed microcatheter blank comprising: a hollow tube having a proximal end, a distal end, and an elongate lumen extending between the proximal and distal ends of the hollow tube; and first and second flat regions extending along opposite sides of the hollow tube.

In one embodiment, the method of manufacturing a barbed microcatheter may comprise: removing material from the first and second flat regions of the barbed microcatheter blank to form barbs projecting outwardly from opposite sides of the hollow tube; forming a fluid outlet opening in the wall of the hollow tube using one or more cutting elements, the fluid outlet opening being in fluid communication with the elongate lumen of the hollow tube; forming a tissue anchor connected to the proximal end of the hollow tube; and securing the surgical needle with the distal end of the hollow tube.

In one embodiment, a method of delivering a therapeutic fluid to tissue preferably comprises positioning a barbed microcatheter adjacent a wound having a first wound end and a second wound end, whereby the barbed microcatheter may comprise: a hollow tube having an elongated lumen extending between a first end and a second end of the hollow tube; barbs projecting outwardly from opposite sides of the hollow tube; a fluid outlet opening formed in the hollow tube in fluid communication with the elongated lumen; a tissue anchor secured to the first end of the hollow tube; and a needle secured to the second end of the hollow tube.

In one embodiment, a method of delivering a therapeutic fluid to tissue can include using a needle to form a first tissue opening at a first end of a wound and pulling a hollow tube completely through the first tissue opening until a tissue anchor abuts tissue at the first end of the wound.

In one embodiment, a method of delivering a therapeutic fluid to tissue may include using a needle to form a second tissue opening at a second end of a wound and pulling a hollow tube completely through the second tissue opening such that barbs projecting outwardly from opposite sides of the hollow tube engage tissue within the wound between the first and second ends of the wound.

In one embodiment, a method of delivering a therapeutic fluid to tissue advantageously includes passing a needle through a skin layer of a patient such that the needle and a second end portion of the hollow tube are external to the patient.

In one embodiment, a method of delivering a therapeutic fluid to a tissue may comprise: cutting the second end of the hollow tube for separating the needle from the hollow tube; and introducing a therapeutic fluid into the cut second end of the hollow tube such that the therapeutic fluid flows into the elongate lumen and through the fluid outlet opening for infusing the wound with the therapeutic fluid.

In one embodiment, the intermediate section of the hollow tube comprising the barb and the fluid outlet opening is preferably located between the first end and the second end of the wound after the needle has passed through the skin layer for location outside the patient.

In one embodiment, the intermediate section of the hollow tube is disposed within the closed wound after the barbed microcatheter has been positioned within the wound.

In one embodiment, the intermediate section of the hollow tube extends along a linear path between the first end and the second end of the wound after the barbed microcatheter has been positioned within the wound.

In one embodiment, the intermediate section of the hollow tube extends along a non-linear path between the first end and the second end of the wound after the barbed microcatheter has been positioned within the wound.

These and other preferred embodiments of the present patent application will be described in more detail herein.

Drawings

Fig. 1 is a top view of a barbed microcatheter with a fluid outlet opening according to one embodiment of the present patent application.

Fig. 2A is a perspective view of a barbed microcatheter having a fluid outlet opening according to one embodiment of the present patent application.

Figure 2B is a top plan view of the barbed microcatheter shown in figure 2A.

Fig. 2C is a bottom view of the barbed microcatheter shown in fig. 2A-2B.

Fig. 2D is a proximal end view of the barbed microcatheter shown in fig. 2A-2C.

Fig. 2E is a left side view of the barbed microcatheter shown in fig. 2A-2D.

Fig. 3 is a cross-sectional view of the barbed microcatheter shown in fig. 2A-2E.

Fig. 4A is a perspective view of a microcatheter blank for forming a barbed microcatheter having a fluid outlet opening according to one embodiment of the present patent application.

Fig. 4B is a cross-sectional view of the microcatheter blank shown in fig. 4A.

Fig. 5 is a perspective view of a press die for forming a microcatheter blank having a flat transverse region extending along the length of the microcatheter blank according to one embodiment of the present application.

Fig. 6 is a perspective view of a microcatheter blank having a flat transverse region extending along the length of the microcatheter blank according to one embodiment of the present application.

Fig. 7 is a perspective view of a compaction roller for forming a microcatheter blank having a flat transverse region extending along the length of the microcatheter blank according to one embodiment of the present application.

Fig. 8 is a perspective view of a cutting die for cutting barbs in a flat transverse region extending along the length of a microcatheter blank according to one embodiment of the present patent application.

Fig. 9 is a perspective view of the barbed microcatheter blank of fig. 8.

Fig. 10A is a perspective view of a needle for forming a fluid outlet opening in the microcatheter blank of fig. 9 according to one embodiment of the present patent application.

Fig. 10B is an enlarged view of the distal end of the needle shown in fig. 10A.

Figure 11 is a perspective view of a die for forming a barbed microcatheter with a fluid outlet opening according to one embodiment of the present patent application.

Fig. 12 is a top plan view of a barbed microcatheter with a fluid outlet opening formed in the top side of the hollow tube according to one embodiment of the present patent application.

Figure 13 is a top plan view of a barbed microcatheter having a hollow tube with spaced apart fluid outlet openings of different sizes according to one embodiment of the present patent application.

Fig. 14A is a perspective view of a die for forming spaced apart fluid outlet openings in a hollow tube of a barbed microcatheter according to one embodiment of the present patent application.

Fig. 14B is a side view of the die shown in fig. 14A.

Fig. 15A is a perspective view of a die for forming spaced apart fluid outlet openings in a hollow tube of a barbed microcatheter according to one embodiment of the present patent application.

Fig. 15B is a side view of the die shown in fig. 15A.

Figure 16 is a top plan view of a barbed microcatheter with spaced apart fluid outlet openings according to one embodiment of the present patent application.

Figure 17A is a perspective view of a barbed microcatheter with spaced apart exit slits according to one embodiment of the present patent application.

Figure 17B is a top plan view of the barbed microcatheter shown in figure 17A.

Fig. 17C is a bottom view of the barbed microcatheter shown in fig. 17A-17B.

Fig. 17D is a proximal end view of the barbed microcatheter shown in fig. 17A-17C.

Fig. 17E is a left side view of the barbed microcatheter shown in fig. 17A-17D.

Fig. 18 is a cross-sectional view of the barbed microcatheter shown in fig. 17A-17E.

Fig. 19 is a perspective view of a die for forming spaced apart fluid outlet slits in the top surface of a hollow tube of a barbed microcatheter according to one embodiment of the present patent application.

Fig. 20A is a perspective view of a cutting blade for forming a fluid outlet slit in a hollow tube of a barbed microcatheter according to one embodiment of the present patent application.

Fig. 20B is an enlarged view of the distal end of the cutting blade shown in fig. 20A.

Fig. 21 illustrates a first stage of a method of forming a fluid exit slit in a barbed microcatheter hollow tube according to one embodiment of the present patent application.

Fig. 22 illustrates a second stage of the method of forming a fluid outlet slit in a barbed microcatheter hollow tube according to one embodiment of the present patent application.

Figure 23 illustrates a third stage of the method of forming a fluid exit slit in a barbed microcatheter hollow tube according to one embodiment of the present patent application.

Fig. 24 illustrates a fourth stage of the method of forming a fluid exit slit in a barbed microcatheter hollow tube according to one embodiment of the present patent application.

Fig. 25A is a perspective view of a top side of a die for forming a fluid outlet slit in a hollow body of a barbed microcatheter according to one embodiment of the present patent application.

Fig. 25B is another perspective side view of the die shown in fig. 25A.

Fig. 25C shows a stage of a method of forming spaced apart fluid outlet slits in a hollow tube of a barbed microcatheter using the die of fig. 25A and 25B according to one embodiment of the present patent application.

Fig. 25D is a side view of the die shown in fig. 25C.

Fig. 26 is a top plan view of a barbed microcatheter according to one embodiment of the present patent application comprising a hollow tube having spaced apart fluid outlet slits formed in the top side of the hollow tube.

Figure 27A illustrates a first stage of a method for infusing therapeutic fluid into a wound using a barbed microcatheter according to one embodiment of the present patent application.

Figure 27B illustrates a second stage of a method of infusing therapeutic fluid into a wound using a barbed microcatheter according to one embodiment of the present patent application.

Figure 27C illustrates a third stage of a method of infusing therapeutic fluid into a wound using a barbed microcatheter according to one embodiment of the present patent application.

Figure 28A illustrates a first stage of a method of infusing therapeutic fluid into a wound using a barbed microcatheter having a non-linear configuration according to one embodiment of the present patent application.

Figure 28B illustrates a second stage of a method of infusing therapeutic fluid into a wound using a barbed microcatheter having a non-linear configuration according to one embodiment of the present patent application.

Figure 28C illustrates a third stage of a method of infusing therapeutic fluid into a wound using a barbed microcatheter having a non-linear configuration according to one embodiment of the present patent application.

Detailed Description

Referring to fig. 1, in one embodiment, the barbed microcatheter 100 preferably comprises a hollow tube 102 having a proximal end 104 and a distal end 106. In one embodiment, the barbed microcatheter 100 preferably has a length L of about 2 inches to 12 inches, and more preferably about 7 inches to 8 inches₁. The barbed microcatheter 100 advantageously includes barbs 108 spaced apart from one another along the length of the hollow tube 102 and projecting from opposite sides of the hollow tube. In one embodiment, the barbed microcatheter comprises a plurality ofA plurality of fluid outlet openings 110 formed in the outer wall of the hollow tube 102 and spaced apart from each other along the length of the hollow tube. In one embodiment, hollow tube 102 has an elongated lumen extending along the length of the hollow tube. The fluid outlet opening 110 is preferably in fluid communication with the elongated lumen such that fluid flowing through the elongated lumen of the hollow tube can exit the hollow tube via the fluid outlet opening. In one embodiment, the barbed microcatheter 100 may comprise: a tissue anchor 112 secured to the proximal end 104 of the hollow tube 102; and a surgical needle 114 secured to the distal end 106 of the hollow tube 102.

Referring to fig. 2A-2E, in one embodiment, the barbed microcatheter 100 preferably comprises a hollow tube 102 with a fluid outlet opening 110 formed in an outer wall 116 of the hollow tube 102. In one embodiment, the fluid outlet openings 110 are preferably spaced apart from each other along the length of the hollow tube 102. In one embodiment, the fluid outlet opening 110 is a circular hole. In one embodiment, the outer wall 116 of the hollow tube 102 has an outer surface 118 and an inner surface 120 surrounding an elongated lumen 122 of the hollow tube 102. The elongated lumen preferably extends along the length of the hollow tube and is in fluid communication with the spaced apart fluid outlet openings such that a fluid (e.g., a therapeutic fluid) can be dispensed from the barbed microcatheter.

In one embodiment, the barbed microcatheter 100 preferably includes a plurality of barbs 108 extending from the side of the hollow tube 102. The plurality of barbs 108 are preferably spaced apart from one another along the length of the hollow tube 102. In one embodiment, the barbs 108 may be symmetrically arranged in barb pairs spaced apart from each other along the length of the hollow tube, whereby the barbs in each barb pair extend away from each other on opposite sides of the hollow tube 102.

Referring to fig. 2B, in one embodiment, the fluid outlet openings 110 (e.g., circular holes having a diameter) are spaced apart from each other along the length of the hollow tube 102 of the barbed microcatheter 100. In one embodiment, the distance D between adjacent spaced apart fluid outlet openings 110₁May be about 4 mm to 25mm, and more preferably about 4 mm to 12 mm. In a fruitIn embodiments, the spaced apart fluid outlet openings 110 may be the same size (i.e., the same diameter). In one embodiment, the spaced apart fluid outlet openings 110 may have different sizes (i.e., different diameters).

Referring to fig. 2B and 2C, in one embodiment, the fluid outlet opening 110 is advantageously formed in the top side of the hollow tube 102 of the barbed microcatheter 100. In one embodiment, the fluid outlet opening is formed in the top side of the hollow tube and no opening is formed on the underside of the hollow tube. Fig. 2C shows the underside of the hollow tube 102 of the barbed microcatheter with no fluid outlet opening formed therein.

Referring to fig. 2D, in one embodiment, the hollow tube 102 of the barbed microcatheter 100 preferably includes an outer wall 116 having an outer surface 118 and an inner surface 120 surrounding an elongated lumen 122. In one embodiment, the fluid outlet opening 110 is formed in the top side of the outer wall 116 of the hollow tube 102. In one embodiment, the fluid outlet opening 110 is advantageously in fluid communication with an elongate lumen 122 extending along the length of the hollow tube such that fluid within the elongate lumen can be dispensed through the fluid outlet opening 110.

In one embodiment, the outer surface 118 of the outer wall 116 of the hollow tube 102 defines an outer diameter OD of about 0.5 millimeters₁. In one embodiment, the inner surface 120 of the outer wall 116 of the hollow tube 102 defines an inner diameter ID of about 0.25 millimeters₁. In one embodiment, the outer diameter OD defined by the outer wall of the hollow tube₁Is an inner diameter ID defined by the inner surface of the outer wall of the hollow tube₁About 2 times higher. In one embodiment, the outer wall 116 of the hollow tube preferably has a thickness T of about 0.125 millimeters₁。

Referring to fig. 2A-2E, in one embodiment, the barbed microcatheter 100 preferably includes barbs 108 protruding from opposite sides of the hollow tube 102. The barbs are preferably spaced apart from each other on each side of the hollow tube. In one embodiment, the thickness T of the barb₂Is the outer diameter OD of the hollow tube 102₁At least 10% of the size of (a). In one embodiment, the thickness T of the barb 108₂Can be about 0.05 mm to0.20 mm. In one embodiment, the pair of barbs 108 may define a tip-to-tip width W of about 1mm to 3mm₁。

Referring to fig. 3, in one embodiment, the barbed microcatheter 100 (fig. 2A-2E) preferably comprises a hollow tube 102 having an outer wall 116, the hollow tube having an outer surface 118 and an inner surface 120 surrounding an elongated lumen 122 extending along the length of the hollow tube 102. The barbed microcatheter 100 preferably includes fluid outlet openings 110 that are spaced apart from one another along the length of the hollow tube 102. In one embodiment, the fluid outlet opening 110 is formed in the top side 124 of the hollow tube 102. In one embodiment, the hollow tube 102 has an underside 126 that is free of fluid outlet openings disposed at the top side 124.

In one embodiment, the fluid outlet opening 110 passes completely through the thickness T of the outer wall 116 of the hollow tube 102₁Such that the fluid outlet opening 110 is in fluid communication with an elongate lumen 122 extending along the length of the hollow tube. In one embodiment, the barbed microcatheter 100 may be implanted into tissue and a fluid (such as a therapeutic fluid) may be introduced into the elongated lumen 122 of the hollow tube 102, whereby the fluid passes through the fluid outlet opening 110 for bathing tissue surrounding the hollow tube. In one embodiment, the barbed microcatheter 100 preferably includes barbs 108 that are spaced apart from one another along the length of the hollow tube 102. In one embodiment, the barbs 108 protruding from the sides of the hollow tube 102 preferably engage the surrounding tissue after the barbed microcatheter 100 has been implanted in the tissue for holding the hollow tube in place within the tissue.

In one embodiment, the barbed microcatheter with the fluid outlet opening is preferably made of an absorbable biocompatible polymeric material. Absorbable polymers may include conventional biocompatible polymers such as lactide, polylactic acid, polyglycolic acid, glycolide, polydioxanone, polycaprolactone, copolymers and blends thereof, and the like.

Referring to fig. 4A and 4B, in one embodiment, the barbed microcatheter 100 shown and described above in fig. 1-3 may be manufactured by first forming a microcatheter blank 128 having an outer wall 130, the microcatheter blank having an outer surface 132, an inner surface 134, and an elongated lumen 136 extending along the length of the microcatheter blank 128. As used herein, the term blank refers to an object (e.g., a hollow tube precursor) intended for further shaping or finishing to make a final product (e.g., a barbed microcatheter having a fluid outlet opening). The microcatheter blank may be drawn for controlling the molecular orientation of the particles of the microcatheter blank, which preferably enhances the strength of the microcatheter blank. As will be described in greater detail herein, the microcatheter blank 128 may be subjected to additional processing steps (e.g., molding, cutting, piercing) for manufacturing a final product or medical device, i.e., a barbed microcatheter having barbs and an exit opening.

Referring to fig. 5, in one embodiment, the microcatheter blank 128 is preferably disposed between an upper die 138 and a lower die 140 of a press or press die. In one embodiment, the upper die 138 and the lower die 140 are preferably moved toward each other for compressing and/or shaping the microcatheter blank 128 therebetween. In one embodiment, when the upper and lower dies 138, 140 are moved to the closed position, the dies compress the microcatheter blank 128 to form first and second

flat regions

142, 144 extending along the sides of the microcatheter blank 128. In one embodiment, the first and second

flat regions

142, 144 preferably extend along the length of the microcatheter blank. In one embodiment, the upper die 138 and the lower die 140 preferably have opposing faces that shape the central portion of the microcatheter blank 128 into the barbed microcatheter hollow tube 102 shown and described above in fig. 2A-2E and 3. Hollow tube 102 preferably includes an elongated lumen 122 extending along its length.

Fig. 6 illustrates an end view of the microcatheter blank 128 after it has been formed and/or shaped by the upper die 138 and lower die 140 shown in fig. 5. The microcatheter blank 128 advantageously includes a first planar region 142 extending along one side of the microcatheter blank 128 and a second planar region 144 extending along an opposite second side of the microcatheter blank. The hollow tube 102 shown and described above in fig. 2A-2E and 3 preferably extends along the length of the microcatheter blank 128. The hollow tube 102 advantageously has an elongated lumen 122 extending along the length of the hollow tube 102. The pressed microcatheter blank 128 having a first planar region 142 and a second planar region 144 preferably has a width W of about 0.75mm to 3mm₂. The first and second

flat regions

142, 144 preferably have a thickness T₂The thickness is the outer diameter OD of the hollow tube 102₁About 10% to 30%.

Referring to fig. 7, in one embodiment, rather than using the upper and lower press dies 148, 150 shown in fig. 5, opposing press rolls 138 ', 140' may be used to form the microcatheter blank 128 shown and described above in fig. 6, which engage the top and bottom sides of the microcatheter blank 128 for forming the first and second flat regions 142, 144 (fig. 6) and the hollow tube 102 shown and described above in fig. 2A-2E and 3.

Referring to fig. 8, in one embodiment, a microcatheter blank 128 having flattened regions 142, 144 (fig. 6) may be placed into a cutting die 146 having an upper cutting die 148 and a lower cutting die 150 having cutting teeth 149. In one embodiment, the upper cutting die 148 and the lower cutting die 150 are movable to a closed position whereby the cutting teeth 149 engage the first planar region 142 and the second planar region 144 (fig. 7) of the microcatheter blank 128 (fig. 6) for forming the barbs 108 (fig. 2A) extending along the length of the hollow tube 102. In one embodiment, rather than using a cutting die, barbs 108 may be formed using a cutting instrument, such as a razor blade that cuts first and second flat regions 142, 144 (fig. 6) of microcatheter blank 128 to form the barbs. In one embodiment, barbs 108 may be formed using one or more lasers that cut first and second

flat regions

142, 144 of microcatheter blank 128 (fig. 6).

Referring to fig. 9, in one embodiment, after barbs 108 are formed from first and second flat regions 142, 144 (fig. 6), microcatheter blank 128 preferably comprises a hollow tube 102 having spaced apart barbs 108 protruding from opposite sides of hollow tube 102. Hollow tube 102 preferably includes an outer wall 116 having an outer surface 118 and an inner surface 120 defining an elongated lumen 122 extending along the length of hollow tube 102.

Referring to fig. 10A and 10B, in one embodiment, a needle 152 having a tip 154 may be utilized to form the fluid outlet opening 110 (fig. 2A) in the outer wall of the hollow tube 102 (fig. 9). The tip 154 of the needle 152 preferably has a tapered region 156 such that the cross-sectional diameter of the needle 152 increases in size between the distal-most end of the tapered region 156 and the proximal end of the tapered region 156. The tapered region 156 of the tip 154 preferably enables the formation of a fluid outlet opening in the hollow tube of the barbed microcatheter, as will be described in greater detail herein. Further, in one embodiment, the tapered region 156 of the tip 154 preferably enables the formation of different sized (e.g., different diameters) fluid outlet openings in the hollow tube of the barbed microcatheter. Thus, the needles 152 may be used to form fluid outlet openings having the same size or fluid outlet openings having different sizes.

Referring to fig. 11, in one embodiment, a microcatheter blank 128 (fig. 9) having a hollow tube 102 and barbs 108 extending from its sides may be placed into a fluid outlet opening die 158 for forming a fluid outlet opening 110 (fig. 2A) in the hollow tube 102. In one embodiment, one or more of the needles 152 shown and described above in fig. 10A-10B may be introduced into the fluid outlet opening die 158 to form the fluid outlet opening 110 in the hollow tube 102 of the microcatheter blank 128. In one embodiment, the needles 152 may slide into and out of the fluid outlet opening die and/or rotate about their longitudinal axis for forming the fluid outlet openings 110 in the hollow tube 102 of the microcatheter blank.

Referring to fig. 12, in one embodiment, after the fluid outlet opening 110 has been formed in the hollow tube 102 using the needle 152 (fig. 11) and the fluid outlet opening die 158 of fig. 11, the microcatheter blank shown in fig. 9 is preferably converted into a barbed microcatheter 100 having spaced apart fluid outlet openings 110. In one embodiment, the fluid outlet opening 110 may be a circular hole or opening formed in the outer wall of the hollow tube 102. The fluid outlet openings 110 may be evenly spaced from each other along the length of the hollow tube. The fluid outlet openings 110 may be of the same size, or may be of different sizes. In one embodiment, the size of the fluid outlet opening increases between the distal end and the proximal end of the hollow tube.

In one embodiment, the press die shown in fig. 5, the press roll shown in fig. 7, and the cutting die shown in fig. 8 may have needles incorporated therein, whereby the fluid outlet openings may be formed at the same time as the first and second flat regions 142, 144 (fig. 5 and 7) are formed, or at the same time as the barbs 108 (fig. 8) are cut.

Referring to fig. 13, in one embodiment, the barbed microcatheter 200 preferably comprises a hollow tube 202 having an elongated lumen 222 extending along its length. In one embodiment, the barbed microcatheter 200 preferably includes fluid outlet openings 210 that are spaced apart from one another along the length of the hollow tube 202. In one embodiment, the diameter of the respective fluid outlet opening 210 can vary in size between the proximal end of the hollow tube 202 (e.g., the end adjacent to the tissue anchor) and the distal end of the hollow tube 202 (e.g., the end adjacent to the surgical needle). In one embodiment, the first fluid outlet opening 210A closer to the proximal end 204 of the hollow tube 202 (e.g., the end closer to the tissue anchor) has a first diameter D₂The first diameter is larger than the toolHaving a second diameter D₃And a second fluid outlet opening 210B. The fluid outlet opening may be tapered in size along the length of the hollow tube (e.g., between the proximal and distal ends of the hollow tube), with the opening being smaller near the fluid source and larger away from the fluid source for maintaining a constant flow of fluid from the fluid outlet opening.

Referring to fig. 14A and 14B, in one embodiment, a fluid outlet opening die 158 shown and described above in fig. 11 may be utilized to form a fluid outlet opening in the hollow tube of the barbed microcatheter. In one embodiment, a pair of

needles

152A, 152B having the same diameter may be utilized to pierce a hollow tube for forming fluid outlet openings having different sizes. In one embodiment, the first needle 152A is inserted to a greater depth than the second needle 152B. The size of the hole will depend on the distance the needle is pushed into the hollow tube. Thus, the first fluid outlet opening 210A (fig. 13) formed by the first needle 152A will have a larger diameter and/or size than the second fluid outlet opening 210B (fig. 13) formed by the second needle 152B. In one embodiment, a plurality of needles (e.g., 10 to 50 needles) may be used to form a plurality of spaced apart fluid outlet openings extending along the length of the barbed microcatheter. The needles may be operated together or independently of each other for forming spaced apart fluid outlet openings.

Referring to fig. 15A and 15B, in one embodiment, a fluid outlet opening die 258 may be used to form barbed microcatheters having fluid outlet openings with different sizes. In one embodiment, fluid outlet opening die 258 may include a larger diameter needle 252A and a smaller diameter needle 252B. In one embodiment, a larger diameter needle 252A may be advanced into the fluid outlet opening die 258 to pierce the hollow tube, forming a larger first fluid outlet opening 210A (fig. 13) in the barbed microcatheter, while a smaller diameter needle 252B may be used to pierce the hollow tube for forming a smaller second fluid outlet opening 210B in the barbed microcatheter. In one embodiment, the fluid outlet opening die may comprise a plurality of needles (e.g., 10 to 50 needles) having progressively increasing diameters for forming fluid outlet openings having progressively increasing sizes and/or diameters.

In one embodiment, the fluid outlet opening of the barbed microcatheter may comprise one or more elongated slits. Referring to fig. 16, in one embodiment, the barbed microcatheter 300 preferably comprises a hollow tube 302 having a proximal end 304 and a distal end 306. The barbed microcatheter 300 advantageously has a plurality of barbs 308 protruding from opposite sides of the hollow tube 302. The barbs 308 are spaced apart from one another along the length of the hollow tube 302. In one embodiment, the barbed microcatheter 300 advantageously includes fluid outlet slits 310 formed in the hollow tube 302 and spaced apart from each other along the length of the hollow tube 302. In one embodiment, the spaced apart fluid outlet slits 310 are advantageously elongate slits formed (e.g., cut, pierced) in the outer wall of the hollow tube 302, whereby these slits are advantageously in fluid communication with an elongate lumen extending along the length of the hollow tube 302. The longitudinal axis of the respective fluid outlet slots 310 may extend along and/or parallel to the longitudinal axis of the hollow tube 302.

In one embodiment, the barbed microcatheter advantageously comprises: a tissue anchor 312 secured to the proximal end 304 of the hollow tube 302; and a surgical needle 314 secured to the distal end 306 of the hollow tube 302. The barbed microcatheter 300 may be positioned in tissue using the surgical needle 314. After implantation in tissue, the barbs 308 preferably hold the barbed microcatheter in place in the tissue.

Referring to fig. 17A-17E, in one embodiment, the barbed microcatheter 300 preferably comprises a hollow tube 102 having a fluid outlet slit 310 extending through an outer wall 316 of the hollow tube 302. The barbed microcatheter 300 advantageously includes a pair of barbs 308 extending from opposite sides of the hollow tube 302. The barb pairs are preferably spaced apart from each other along the length of the hollow tube. The barbed microcatheter 300 shown and described in fig. 17A-17E may have similar dimensions and/or features as the barbed microcatheter shown and described above in fig. 1-3, except for the fluid outlet slit 310 formed on the top side of the hollow tube 302.

Referring to fig. 17D, in one embodiment, the fluid outlet slit 310 preferably passes completely through the outer wall 316 of the hollow tube 302 for providing fluid communication between the elongated lumen 322 of the hollow tube 302 and the fluid outlet slit 310. Thus, fluid passing through the elongate lumen 322 of the hollow tube 302 may flow through the fluid outlet slit 310 for bathing tissue surrounding the exterior of the hollow tube 302 with fluid disposed within the elongate lumen.

Referring to fig. 18, in one embodiment, the barbed microcatheter 300 (fig. 17A-17E) preferably comprises a hollow tube 302 having an outer wall 316, the hollow tube having an outer surface 318 and an inner surface 320 surrounding an elongated lumen 322, the elongated lumen extending along the length of the hollow tube 302. The barbed microcatheter 300 preferably includes fluid outlet slits 310 formed in the top side 324 of the hollow tube 302 and spaced apart from each other along the length of the hollow tube. In one embodiment, fluid (e.g., therapeutic fluid) flowing through the elongated lumen 322 preferably passes through the fluid outlet slit 310 for soaking tissue surrounding the barbed microcatheter with the fluid. The barbed microcatheter 300 advantageously includes outwardly extending barbs 308 that are spaced apart from one another along the length of the hollow tube 302. In one embodiment, the barbs 308 may be symmetrical barb pairs protruding from opposite sides of the hollow tube 302.

Referring to fig. 19, in one embodiment, a fluid outlet slit die 358 and cutting blade 352 may be utilized to form a fluid outlet slit in the top side of the hollow tube 302 of the barbed microcatheter 300 (fig. 18). In one embodiment, the fluid outlet slit die 358 advantageously has a top surface 360 with a recess formed therein adapted to seat the underside of the hollow tube 302 of the barbed microcatheter 300, the barb 308 and the tissue anchor 312. In one embodiment, after the barbed microcatheter 300 has been positioned on top of the punch 358, a cutting blade 352 having a sharpened end may be utilized to form a fluid outlet slit 310 in the top side of the hollow tube 302 (fig. 18).

Referring to fig. 20A and 20B, in one embodiment, the cutting blade 352 preferably has a sharpened tip 354 for forming a fluid outlet slit in the outer wall of the hollow tube of the barbed microcatheter. In one embodiment, sharp point 354 has a cutting edge 362 and sloped sidewalls 365, 366 extending proximally from cutting edge 362. The exact length of the fluid outlet slit formed in the outer tube of the barbed microcatheter or microcatheter blank may be controlled by modifying the extent to which the sharpened tip 354 of the cutting blade 352 is inserted into the hollow tube. In one embodiment, more insertion of the sharp point will result in a longer fluid outlet slit, and less insertion of the sharp point will result in a shorter fluid outlet slit.

Referring to fig. 21, in one embodiment, after the barbed microcatheter 300 has been positioned within the recess formed in the top surface 360 of the fluid outlet slit die 358, the cutting edge 362 of the cutting blade 352 is preferably juxtaposed with the top side of the hollow tube 302 of the barbed microcatheter 300.

Referring to fig. 22, in one embodiment, the cutting edge 362 at the lower end of the cutting blade 352 is lowered onto the outer surface of the hollow tube 302 for cutting and/or piercing the outer wall of the hollow tube 302.

Referring to fig. 23, in one embodiment, as the cutting edge 362 of cutting blade 352 penetrates the outer wall of hollow tube 302, cutting blade 352 is moved in direction DIR1 relative to hollow tube 302 and die 358 for forming fluid outlet slot 310 in the top side of hollow tube 302. In an alternative embodiment, the cutting blade 352 may remain stationary and the punch 358 and barbed microcatheter may be moved relative to the cutting edge 362 of the cutting blade 352 for forming the fluid outlet slit 310 in the top side of the hollow tube 302.

Referring to fig. 24, in one embodiment, after the cutting edge 362 of the cutting blade 352 has formed the elongated fluid outlet slot 310 in the top side of the hollow tube 302, the cutting blade may be retracted such that the hollow tube 302 and the die 358 may be indexed to a next position for forming another fluid outlet slot in the hollow tube. This process may be repeated for forming a plurality of fluid outlet slots (e.g., 25 slots, 50 slots, 100 slots) along the length of the hollow tube 302. In one embodiment, the slits may have the same length. In one embodiment, one or more of the fluid outlet slits may have different lengths.

Referring to fig. 25A-25B, in one embodiment, the fluid outlet slit 310 (fig. 17A-17E) may be formed in a barbed microcatheter by passing a cutting blade 352 (fig. 20A) through an opening provided in the body of the fluid outlet slit die 458. In one embodiment, the fluid outlet slit die 458 preferably includes a top surface 360 having a recess 365 formed therein that seats the microcatheter blank 128 with barbs cut along the sides (FIG. 9). In one embodiment, the fluid outlet slot die 458 advantageously includes a first opening 466 configured to receive the first cutting blade 452A and a second opening 468 configured to receive the second cutting blade 452B. In one embodiment, the cutting edges of the

respective cutting blades

452A, 452B are advanced into the recess 468 formed in the top surface 460 of the die 458 such that the cutting edges are capable of engaging the outer wall of the hollow tube of the catheter blank for forming a fluid outlet slit in the outer wall of the hollow tube.

Referring to fig. 25C and 25D, in one embodiment, the first cutting edge 462A of the first cutting blade 452A is advanced to a greater depth than the second cutting edge 462B of the second cutting blade 452B. Thus, the length of the fluid outlet slit formed by the first cutting blade 452A will be greater than the length of the fluid outlet slit formed by the second cutting blade 452B.

Fig. 26 illustrates a barbed microcatheter 400 formed using the fluid outlet slit die 458 and

cutting blades

452A, 452B shown and described above in fig. 25A-25D. In one embodiment, the barbed microcatheter 400 comprises a hollow tube 402 having an elongated lumen 422 extending along the length of the hollow tube 402. Barbs 408 project from the side of the hollow tube 402. An anchor 412 is secured to the proximal end 404 of the hollow tube 402 of the barbed microcatheter 400. The barbed microcatheter includes a first fluid outlet slit 410A formed in the outer tube 402, the first fluid outlet slit having a first length L₂The first length is greater than the second length L of the second fluid outlet slot 410B formed in the outer tube 402₃. As described above, the respective lengths of the fluid outlet slits 410A, 410B may be controlled by the depth of insertion of the cutting edge of the cutting blade 352 (fig. 20A and 20B), or by controlling the length of the fluid outlet slit cut into the hollow tube 402 as the cutting edge of the cutting blade is moved relative to the hollow tube and the fluid outlet slit die of the hollow tube in which the microcatheter blank (e.g., microcatheter blank 128 shown in fig. 9) is positioned.

In one embodiment, the therapeutic fluid flows through the elongated lumen 422 of hollow tube 402 in direction DIR 2. The therapeutic fluid preferably flows from a fluid source located at the distal end of the hollow tube 402 spaced from the proximal end 404 of the hollow tube. The first fluid outlet slit 410A adjacent the anchor 412 is longer than the second fluid outlet slit 410B distal to the first fluid outlet slit 410A.

Referring to fig. 27A, in one embodiment, a barbed microcatheter 500 is preferably used for infusing therapeutic fluid into the tissue of a patient, such as into a wound of a patient. In one embodiment, the barbed microcatheter 500 preferably comprises a hollow tube 502 having a first end 504 and a second end 506. The barbed microcatheter 500 advantageously includes barbs 508 spaced apart from each other along the length of the hollow tube 502 and projecting from opposite sides of the hollow tube. In one embodiment, the barbed microcatheter comprises a plurality of fluid outlet openings 510 formed in the outer wall of the hollow tube 502 and spaced apart from each other along the length of the hollow tube. In one embodiment, hollow tube 502 has an elongated lumen (e.g., elongated lumen 122 shown in fig. 3) extending along the length of the hollow tube and adapted to receive a therapeutic fluid infused into the tissue of a patient. The fluid outlet opening 510 is preferably in fluid communication with the elongate lumen such that fluid flowing through the elongate lumen of the hollow tube can exit the hollow tube via the fluid outlet opening 510. In one embodiment, the barbed microcatheter 500 may comprise: a tissue anchor 512 secured to first end 504 of hollow tube 502; and a surgical needle 514 secured to second end 506 of hollow tube 502.

In one embodiment, the patient's epidermis E has surgical openings SO formed therein to define a wound W having wound tissue including subcutaneous layer SL and fascia layer FL. The wound has a first end 575 and a second end 585 spaced from the first end 575.

In one embodiment, the barbed microcatheter 500 preferably includes an intermediate section 555 that includes at least some of the fluid outlet openings 510 and the barbs 508. In one embodiment, the barbs 508 in the intermediate section 555 of the barbed microcatheter 500 preferably bite into the tissue within the wound W for anchoring the barbed microcatheter in place within the wound W. In one embodiment, the second end 506 of the hollow tube 502 is preferably free of a fluid outlet opening. In one embodiment, the second end 506 of the hollow tube 502 preferably passes outside the patient such that the needle 514 can be detached from the second end portion of the hollow tube, whereby the therapeutic fluid can be directed into the second end of the hollow tube.

Referring to fig. 27A and 27B, in one embodiment, a method of delivering a therapeutic fluid to tissue advantageously includes positioning a barbed microcatheter 500 adjacent a first end 575 of a wound W. In one embodiment, the needle 514 is used to create a first tissue opening 595 at the first end 575 of the wound and pull the hollow tube 502 completely through the first tissue opening 595 until the tissue anchor 512 abuts the tissue at the first end of the wound W.

In one embodiment, the needle 514 is used to create a second tissue opening 597 at the second end 585 of the wound W and to pull the hollow tube 502 completely through the second tissue opening 597 such that the barbs 508 projecting outwardly from opposite sides of the hollow tube 502 engage tissue within the wound W between the first end 575 and the second end 585 of the wound W.

In one embodiment, the needle 514 is later passed through the patient's epidermis E such that the needle 514 and the second end 506 of the hollow tube 502 are located outside the patient.

Referring to fig. 27B, in one embodiment, the intermediate section 555 of the hollow tube 502 including the barbs 508 and the fluid outlet opening 510 can extend along a linear path between the first end 575 and the second end 585 of the wound W after the barbed microcatheter 500 has been implanted in the wound W. Barbs 508 preferably bite into the tissue within wound W to prevent the hollow tube 502 from sliding or moving in the direction designated DIR 3. Tissue anchor 512 preferably engages tissue at first end 575 of wound W to prevent hollow tube 502 from sliding or moving in a direction designated DIR 4.

In one embodiment, the second end 506 of the hollow tube 502 is cut for separating the needle 514 from the hollow tube 502 and providing access to the elongate lumen extending through the hollow tube 502.

Referring to fig. 27C, in one embodiment, the wound W may be closed, such as by using sutures, staples, tissue fasteners, and tissue adhesives. A container 599 containing a therapeutic fluid may be coupled with the cut second end 506 of hollow tube 502 extending outside the patient for introducing the therapeutic fluid into hollow tube 502. The therapeutic fluid preferably flows into the elongated lumen of the hollow tube and through the fluid outlet opening 510 (fig. 27B) for infusion of the wound W with the therapeutic fluid.

Referring to fig. 28A, in one embodiment, a barbed microcatheter 600 is preferably used for infusing therapeutic fluid into the tissue of a patient, such as into a wound of a patient. In one embodiment, the barbed microcatheter 600 preferably comprises a hollow tube 602 having a first end 604 and a second end 606. The barbed microcatheter 600 advantageously includes barbs 608 spaced apart from each other along the length of the hollow tube 602 and projecting from opposite sides of the hollow tube. In one embodiment, the barbed microcatheter comprises a plurality of fluid outlet openings 610 formed in the outer wall of the hollow tube 602 and spaced apart from each other along the length of the hollow tube. In one embodiment, hollow tube 602 has an elongated lumen (e.g., elongated lumen 122 shown in fig. 3) extending along the length of the hollow tube and adapted to receive a therapeutic fluid infused into the tissue of a patient. The fluid outlet opening 610 is preferably in fluid communication with the elongate lumen such that fluid flowing through the elongate lumen of the hollow tube can exit the hollow tube via the fluid outlet opening 610. In one embodiment, the barbed microcatheter 600 may comprise: a tissue anchor 612 secured to the first end 604 of the hollow tube 602; and a surgical needle 614 secured to the second end 606 of the hollow tube 602.

In one embodiment, the patient's epidermis E has surgical openings SO formed therein to define a wound W having wound tissue including subcutaneous layer SL and fascia layer FL. The wound has a first end portion 675 and a second end portion 685 spaced apart from the first end portion 675.

In one embodiment, the barbed microcatheter 600 preferably includes an intermediate section 655 that includes at least some of the fluid outlet openings 610 and at least some of the barbs 608. In one embodiment, the barbs 608 in the intermediate section 655 of the barbed microcatheter 600 preferably bite into the tissue within the wound W for anchoring the barbed microcatheter in place within the wound W. In one embodiment, the second end 606 of the hollow tube 602 is preferably free of a fluid outlet opening. In one embodiment, the second end 606 of the hollow tube 602 preferably passes outside the patient such that the needle 614 can be detached from the second end portion of the hollow tube, whereby the therapeutic fluid can be directed into the second end of the hollow tube.

Referring to fig. 28A and 28B, in one embodiment, a method of delivering therapeutic fluid to tissue advantageously includes positioning a barbed microcatheter 600 adjacent a first end 675 of a wound W. In one embodiment, the needle 614 is used to form a first tissue opening 695 at the first end 675 of the wound and the hollow tube 602 is pulled completely through the first tissue opening 695 until the tissue anchor 612 abuts the tissue at the first end of the wound W. Additional occlusion of the tissue is made using the needle 614 so that the hollow tube 602 follows a non-linear path between the first end 675 and the second end 685 of the wound W.

In one embodiment, the needle 614 is used to form a final tissue opening 697 at the second end 685 of the wound W and to pull the hollow tube 602 completely through the second tissue opening 697 such that barbs 608 projecting outwardly from opposite sides of the non-linearly configured hollow tube 602 engage tissue within the wound W between the first end 675 and the second end 685 of the wound W.

In one embodiment, the needle 614 is later passed through the epidermis E of the patient such that the needle 614 and the second end 606 of the hollow tube 602 are located outside the patient.

Referring to fig. 28B, in one embodiment, the intermediate section 655 of the hollow tube 602 including the barb 608 and the fluid outlet opening 610 may extend along a non-linear path between the first end 675 and the second end 685 of the wound W after the barbed microcatheter 600 has been implanted in the wound W. Barbs 608 preferably bite into the tissue within wound W to prevent hollow tube 602 from sliding or moving in the direction designated DIR 5. The tissue anchors 612 preferably engage tissue at the first end 675 of the wound W to prevent the hollow tube 602 from sliding or moving in a direction designated as DIR 6.

In one embodiment, the second end 606 of the hollow tube 602 is cut for separating the needle 614 from the hollow tube 602 and providing access to the elongate lumen extending through the hollow tube 602.

Referring to fig. 28C, in one embodiment, the wound W may be closed, such as by using sutures, staples, tissue fasteners, and tissue adhesives. A container 699 containing a therapeutic fluid may be coupled with a cut second end 606 of the hollow tube 602 that extends outside of the patient for introducing the therapeutic fluid into the hollow tube 602. The therapeutic fluid preferably flows into the elongate lumen of the hollow tube and through the fluid outlet opening 610 (fig. 28B) for infusion of the wound W with the therapeutic fluid.

While the foregoing is directed to embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow. For example, the present invention contemplates that any feature shown in any embodiment or incorporated by reference herein can be combined with any feature shown in any other embodiment or incorporated by reference herein described and still fall within the scope of the present invention.

Claims

1. A barbed microcatheter for delivering a fluid, said barbed microcatheter comprising:

a hollow tube having a proximal end, a distal end, and an elongated lumen extending between the proximal and distal ends of the hollow tube;

a barb projecting outwardly from the hollow tube; and

a plurality of fluid outlet openings formed in the hollow tube, the plurality of fluid outlet openings in fluid communication with the elongated lumen of the hollow tube.

2. The barbed microcatheter according to claim 1, wherein said fluid outlet openings are spaced apart from one another between said proximal end and said distal end of said hollow tube.

3. The barbed microcatheter according to claim 1, wherein said fluid outlet openings are evenly spaced apart from one another between said proximal end and said distal end of said hollow tube.

4. The barbed microcatheter according to claim 2, wherein each of said fluid outlet openings has the same dimensions.

5. The barbed microcatheter according to claim 2, wherein two or more of said fluid outlet openings have different sizes.

6. The barbed microcatheter according to claim 2, wherein said fluid outlet opening comprises a circular hole.

7. The barbed microcatheter according to claim 2, wherein said fluid outlet opening comprises an elongated slit.

8. The barbed microcatheter according to claim 8, wherein said hollow tube has a longitudinal axis extending between said proximal end and said distal end of said hollow tube, and wherein said elongated slit has a length extending along a common axis that is parallel to said longitudinal axis of said hollow tube.

9. The barbed microcatheter according to claim 1, wherein said hollow tube comprises an outer surface and an inner surface surrounding said elongated lumen, and wherein said fluid outlet opening is formed in said hollow tube and extends from said outer surface of said hollow tube to said inner surface of said hollow tube for fluid communication with said elongated lumen.

10. The barbed microcatheter according to claim 10, wherein said inner surface of said hollow tube defines an inner cross-sectional diameter of said hollow tube and an outer surface of said cylindrical wall defines an outer cross-sectional diameter of said hollow tube that is about 2 times said inner cross-sectional diameter of said hollow tube.

11. The barbed microcatheter according to claim 11, wherein said hollow tube has a wall thickness of about 0.125mm, said outer cross-sectional diameter of said hollow tube is about 0.50mm, and said inner cross-sectional diameter of said hollow tube is about 0.25 mm.

12. The barbed microcatheter according to claim 1, wherein said barbed microcatheter comprises an absorbable biocompatible polymer.

13. A barbed microcatheter for delivering fluid to tissue, said barbed microcatheter comprising:

a hollow tube having a proximal end, a distal end, and an elongated lumen disposed inside the hollow tube extending between the proximal and distal ends of the hollow tube;

a barb projecting outwardly from the outer surface of the hollow tube; and

a plurality of fluid outlet openings formed in the outer surface of the hollow tube, the plurality of fluid outlet openings in fluid communication with the elongate lumen of the hollow tube, wherein the fluid outlet openings are evenly spaced apart from each other between the proximal and distal ends of the hollow tube.

14. The barbed microcatheter according to claim 14, wherein each of said fluid outlet openings has the same dimensions.

15. The barbed microcatheter according to claim 14, wherein two or more of said fluid outlet openings have different sizes.

16. The barbed microcatheter according to claim 14, wherein said fluid outlet opening has a shape selected from the group consisting of a circular hole and an elongated slit.

17. The barbed microcatheter according to claim 14, wherein the elongated lumen of the hollow tube defines a cross-sectional diameter of about 0.25mm, and wherein the outer surface of the hollow tube defines a cross-sectional diameter of about 0.50 mm.

18. The barbed microcatheter according to claim 14, further comprising:

an anchor secured to the proximal end of the hollow tube; and

a surgical needle secured to the distal end of the hollow tube.

19. A barbed microcatheter for delivering fluid to tissue, said barbed microcatheter comprising:

a plurality of barbs projecting outwardly from the outer surface of the hollow tube;

a plurality of fluid outlet openings formed in the outer surface of the hollow tube, the plurality of fluid outlet openings in fluid communication with the elongate lumen of the hollow tube, wherein the fluid outlet openings are evenly spaced apart from each other between the proximal and distal ends of the hollow tube;

an anchor secured to the proximal end of the hollow tube; and

a surgical needle secured to the distal end of the hollow tube, wherein two or more of the fluid outlet openings are of different sizes, including a first fluid outlet opening of a first size positioned adjacent the anchor and a second fluid outlet opening of a second size positioned adjacent the surgical needle, the second size being smaller than the first size of the first fluid outlet opening.

20. The barbed microcatheter according to claim 20, further comprising an antimicrobial agent coated or impregnated into said barbed microcatheter.

21. The barbed microcatheter according to claim 21, wherein said antimicrobial agent is selected from the group of antimicrobial agents consisting of: triclosan, chlorhexidine, povidone iodine, and silver compounds.

22. A method of manufacturing a barbed microcatheter having a fluid outlet opening, said method comprising:

compressing first and second sides of a polymer blank to form a barbed microcatheter blank, the barbed microcatheter blank comprising a first planar region extending along the first side of the barbed microcatheter blank, a second planar region extending along the second side of the barbed microcatheter blank, and a hollow tube having an elongated lumen located between the first planar region and the second planar region;

removing material from the first and second flat regions of the barbed microcatheter blank to form barbs projecting outwardly from opposite sides of the hollow tube;

forming a fluid outlet opening in a wall of the hollow tube, the fluid outlet opening being in fluid communication with the elongated lumen of the hollow tube.

23. The method of claim 23, further comprising:

compressing the proximal end of the polymeric blank to form a tissue anchor connected to the proximal end of the hollow tube; and

securing a needle to the distal end of the hollow tube.

24. The method of claim 23, further comprising forming the fluid outlet opening in the wall of the hollow tube using at least one cutting element.

25. The method of claim 25, wherein the forming a fluid outlet opening step comprises:

forming a first fluid outlet opening having a first size in the wall of the hollow tube;

forming a second fluid outlet opening having a second size in the wall of the hollow tube, the second size being larger than the first size of the first fluid outlet opening.

26. The method of claim 25, wherein the forming a fluid outlet opening step comprises forming a series of progressively larger fluid outlet openings in the wall of the hollow tube.

27. The method of claim 23, wherein the fluid outlet opening is formed simultaneously during the forming fluid outlet opening step.

28. The method of claim 23, wherein the fluid outlet openings are formed independently of one another and at different times during the step of forming fluid outlet openings.

29. The method of claim 25, wherein the at least one cutting element comprises a cutting element selected from the group consisting of: a needle, a needle having a tapered tip, and a cutting blade.

30. The method of claim 24, wherein the tissue anchor connected to the proximal end of the hollow tube comprises a flat tab having a length and a width.

31. The method of claim 23, wherein the step of compressing the first and second sides of the polymeric blank comprises:

placing the polymeric blank into a press die having an upper press die portion overlying the polymeric blank and a lower press die portion opposite the upper press die portion and below the polymeric blank;

moving the press die to a closed position for compressing upper and lower surfaces of the first and second sides of the polymeric blank for forming the first and second flat areas and the hollow tube.

32. The method of claim 32 wherein the upper press die section includes a plurality of cutting elements projecting from an underside of the upper press die section, wherein the cutting elements engage the hollow tube for forming the fluid outlet opening in the hollow tube when the press die is in the closed position.

33. The method as claimed in claim 23, wherein said removing material step comprises cutting said first and second flat regions of said barbed microcatheter blank to form said barbs projecting outwardly from said opposite sides of said hollow tube.

34. The method of claim 34, wherein the cutting step comprises:

placing the barbed microcatheter blank comprising the first and second flat regions and the hollow tube into a cutting die having an upper cutting die portion and a lower cutting die portion opposite the upper cutting die portion;

moving the cutting die to a closed position for cutting the first and second flat regions of the barbed microcatheter blank for forming the barbs projecting outwardly from the opposite sides of the hollow tube.

35. The method of claim 35, wherein the upper cutting die section includes a plurality of cutting elements protruding from an underside of the upper cutting die section, wherein the cutting elements engage the hollow tube for forming the fluid outlet opening in the hollow tube when the cutting die is in the closed position.

36. The method of claim 23, wherein the step of compressing the first and second sides of the polymer blank comprises compressing upper and lower surfaces of the first and second sides of the polymer blank using compression rollers for forming the first and second flat regions of the barbed microcatheter blank and the hollow tube.

37. A method of manufacturing a barbed microcatheter having a fluid outlet opening, said method comprising:

obtaining a barbed microcatheter blank comprising: a hollow tube having a proximal end, a distal end, and an elongated lumen extending between the proximal and distal ends of the hollow tube; and first and second flat regions extending along opposite sides of the hollow tube;

removing material from the first and second flat regions of the barbed microcatheter blank to form barbs projecting outwardly from the opposite sides of the hollow tube;

forming a fluid outlet opening in a wall of the hollow tube using one or more cutting elements, the fluid outlet opening being in fluid communication with the elongate lumen of the hollow tube;

forming a tissue anchor connected to the proximal end of the hollow tube;

securing a surgical needle with the distal end of the hollow tube.

38. A method of delivering a therapeutic fluid to tissue, the method comprising:

positioning a barbed microcatheter adjacent a wound having a first end and a second end, said barbed microcatheter comprising: a hollow tube having an elongated lumen extending between a first end and a second end of the hollow tube; barbs projecting outwardly from opposite sides of the hollow tube; a fluid outlet opening formed in the hollow tube in fluid communication with the elongated lumen; a tissue anchor secured to the first end of the hollow tube; and a needle secured to the second end of the hollow tube;

using the needle to form a first tissue opening at the first end of the wound and pull the hollow tube completely through the first tissue opening until the tissue anchor abuts tissue at the first end of the wound;

using the needle to form a second tissue opening at the second end of the wound and pull the hollow tube completely through the second tissue opening such that the barbs projecting outwardly from opposite sides of the hollow tube engage tissue within the wound between the first and second ends of the wound;

passing the needle through a skin layer of a patient such that the needle and the second end of the hollow tube are located outside the patient;

cutting the second end of the hollow tube for separating the needle from the hollow tube;

introducing a therapeutic fluid into the cut second end of the hollow tube such that the therapeutic fluid flows into the elongate lumen and through the fluid outlet opening for infusion of the wound with the therapeutic fluid.

39. The method of claim 39, wherein after the step of passing the needle through the layer of skin, an intermediate section of the hollow tube comprising the barb and the fluid outlet opening is located between the first end and the second end of the wound.

40. The method of claim 40, further comprising closing the wound such that the intermediate section of the hollow tube is disposed within the closed wound.

41. The method of claim 40, wherein the intermediate section of the hollow tube extends along a linear path between the first end and the second end of the wound.

42. The method of claim 40, wherein the intermediate section of the hollow tube extends along a non-linear path between the first end and the second end of the wound.