US20030015203A1 - Device, system and method for implantation of filaments and particles in the body - Google Patents

Device, system and method for implantation of filaments and particles in the body Download PDF

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US20030015203A1
US20030015203A1 US10/172,788 US17278802A US2003015203A1 US 20030015203 A1 US20030015203 A1 US 20030015203A1 US 17278802 A US17278802 A US 17278802A US 2003015203 A1 US2003015203 A1 US 2003015203A1
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filament
method
inserting
tissue
subject
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Abandoned
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US10/172,788
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Joshua Makower
Claude Vidal
Thomas Banks
Russell Redmond
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Joshua Makower
Claude Vidal
Banks Thomas F.
Redmond Russell J.
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Priority to US825995P priority Critical
Priority to US1679296P priority
Priority to US08/734,638 priority patent/US6090063A/en
Priority to US58775500A priority
Application filed by Joshua Makower, Claude Vidal, Banks Thomas F., Redmond Russell J. filed Critical Joshua Makower
Priority to US10/172,788 priority patent/US20030015203A1/en
Publication of US20030015203A1 publication Critical patent/US20030015203A1/en
Application status is Abandoned legal-status Critical

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    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61BDIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B17/00Surgical instruments, devices or methods, e.g. tourniquets
    • A61B17/12Surgical instruments, devices or methods, e.g. tourniquets for ligaturing or otherwise compressing tubular parts of the body, e.g. blood vessels, umbilical cord
    • A61B17/12022Occluding by internal devices, e.g. balloons or releasable wires
    • A61B17/12131Occluding by internal devices, e.g. balloons or releasable wires characterised by the type of occluding device
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61BDIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B17/00Surgical instruments, devices or methods, e.g. tourniquets
    • A61B17/12Surgical instruments, devices or methods, e.g. tourniquets for ligaturing or otherwise compressing tubular parts of the body, e.g. blood vessels, umbilical cord
    • A61B17/12022Occluding by internal devices, e.g. balloons or releasable wires
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61BDIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B17/00Surgical instruments, devices or methods, e.g. tourniquets
    • A61B17/12Surgical instruments, devices or methods, e.g. tourniquets for ligaturing or otherwise compressing tubular parts of the body, e.g. blood vessels, umbilical cord
    • A61B17/12022Occluding by internal devices, e.g. balloons or releasable wires
    • A61B17/12099Occluding by internal devices, e.g. balloons or releasable wires characterised by the location of the occluder
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61BDIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B17/00Surgical instruments, devices or methods, e.g. tourniquets
    • A61B17/12Surgical instruments, devices or methods, e.g. tourniquets for ligaturing or otherwise compressing tubular parts of the body, e.g. blood vessels, umbilical cord
    • A61B17/12022Occluding by internal devices, e.g. balloons or releasable wires
    • A61B17/12099Occluding by internal devices, e.g. balloons or releasable wires characterised by the location of the occluder
    • A61B17/12109Occluding by internal devices, e.g. balloons or releasable wires characterised by the location of the occluder in a blood vessel
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61BDIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B17/00Surgical instruments, devices or methods, e.g. tourniquets
    • A61B17/12Surgical instruments, devices or methods, e.g. tourniquets for ligaturing or otherwise compressing tubular parts of the body, e.g. blood vessels, umbilical cord
    • A61B17/12022Occluding by internal devices, e.g. balloons or releasable wires
    • A61B17/12099Occluding by internal devices, e.g. balloons or releasable wires characterised by the location of the occluder
    • A61B17/12109Occluding by internal devices, e.g. balloons or releasable wires characterised by the location of the occluder in a blood vessel
    • A61B17/12113Occluding by internal devices, e.g. balloons or releasable wires characterised by the location of the occluder in a blood vessel within an aneurysm
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61BDIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B17/00Surgical instruments, devices or methods, e.g. tourniquets
    • A61B17/12Surgical instruments, devices or methods, e.g. tourniquets for ligaturing or otherwise compressing tubular parts of the body, e.g. blood vessels, umbilical cord
    • A61B17/12022Occluding by internal devices, e.g. balloons or releasable wires
    • A61B17/12131Occluding by internal devices, e.g. balloons or releasable wires characterised by the type of occluding device
    • A61B17/1214Coils or wires
    • A61B17/12145Coils or wires having a pre-set deployed three-dimensional shape
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61BDIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B17/00Surgical instruments, devices or methods, e.g. tourniquets
    • A61B17/12Surgical instruments, devices or methods, e.g. tourniquets for ligaturing or otherwise compressing tubular parts of the body, e.g. blood vessels, umbilical cord
    • A61B17/12022Occluding by internal devices, e.g. balloons or releasable wires
    • A61B17/12131Occluding by internal devices, e.g. balloons or releasable wires characterised by the type of occluding device
    • A61B17/12181Occluding by internal devices, e.g. balloons or releasable wires characterised by the type of occluding device formed by fluidized, gelatinous or cellular remodelable materials, e.g. embolic liquids, foams or extracellular matrices
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61BDIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B17/00Surgical instruments, devices or methods, e.g. tourniquets
    • A61B17/12Surgical instruments, devices or methods, e.g. tourniquets for ligaturing or otherwise compressing tubular parts of the body, e.g. blood vessels, umbilical cord
    • A61B17/12022Occluding by internal devices, e.g. balloons or releasable wires
    • A61B17/12131Occluding by internal devices, e.g. balloons or releasable wires characterised by the type of occluding device
    • A61B17/12181Occluding by internal devices, e.g. balloons or releasable wires characterised by the type of occluding device formed by fluidized, gelatinous or cellular remodelable materials, e.g. embolic liquids, foams or extracellular matrices
    • A61B17/12186Occluding by internal devices, e.g. balloons or releasable wires characterised by the type of occluding device formed by fluidized, gelatinous or cellular remodelable materials, e.g. embolic liquids, foams or extracellular matrices liquid materials adapted to be injected
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61BDIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B17/00Surgical instruments, devices or methods, e.g. tourniquets
    • A61B17/04Surgical instruments, devices or methods, e.g. tourniquets for suturing wounds; Holders or packages for needles or suture materials
    • A61B17/0469Suturing instruments for use in minimally invasive surgery, e.g. endoscopic surgery
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61BDIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B17/00Surgical instruments, devices or methods, e.g. tourniquets
    • A61B17/00234Surgical instruments, devices or methods, e.g. tourniquets for minimally invasive surgery
    • A61B2017/00349Needle-like instruments having hook or barb-like gripping means, e.g. for grasping suture or tissue
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61BDIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B17/00Surgical instruments, devices or methods, e.g. tourniquets
    • A61B2017/00526Methods of manufacturing
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61BDIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B90/00Instruments, implements or accessories specially adapted for surgery or diagnosis and not covered by any of the groups A61B1/00 - A61B50/00, e.g. for luxation treatment or for protecting wound edges
    • A61B90/39Markers, e.g. radio-opaque or breast lesions markers

Abstract

A method of introducing continuous lengths of filament into the body in surgical procedures in which it is desirable to place a significant amount of material into the body through a small portal. The material so introduced may serve to bulk a tissue or cavity of the body or to occlude a vas, as well as to introduce diagnostic or therapeutic agents into a site in the body. A device for implementing the method has a mechanism for feeding the filament through a conduit in such a manner that sufficient force is applied to the filament that it is forced into the desired site. In one embodiment, a system of reciprocating cannulae and synchronized grippers is used to supply the requisite force to the filament.

Description

    TECHNICAL FIELD
  • The present invention relates to a device and method for therapeutic insertion of suture and other materials into body tissue in filamentous and particulate form. [0001]
  • BACKGROUND OF THE INVENTION
  • Increasingly in medicine and surgery, the need arises to place a mass of material either into body tissue or into a space in the body proximate to body tissue for various clinical purposes. These purposes include the bulking of tissue as a therapy for intrinsic sphincteric deficiency (ISD) which gives rise to incontinence. In some types of incontinence, a decrease in urethral resistance leads to urinary leakage during stress. This leakage is embarrassing, and may cause the person to change their life-style to avoid activity. Recently, various injectable materials have been suggested for the purpose of ‘bulking’ the periurethral space, coapting the urethra, and thus increasing the urethral resistance. [0002]
  • Other clinical applications include the implantation of material include the occlusion of aneurysms, arteriovenous malformations (AVMs), and fistulas, as well as the occlusion of the blood supply to tumors, especially cranial tumors, prior to surgery to reduce bleeding during surgery. [0003]
  • To insure that such procedures are minimally invasive, it was clinically determined that bulking, for example, should be accomplished through needle injection. Due to the use of a needle, it was believed that it was necessary to reduce the material to a liquid suspension or particulate so that it might be capable of being passed through a needle into the tissue. This reduced the number of candidate materials significantly. Teflon (PTFE) particles, silicone particles, collagen suspensions, and various other materials were tried. Most of the problems associated with the therapy were associated with the material. For example, collagen resorbed too quickly, creating the need for many repeat therapies. Teflon particles migrate through the body and are thus clinically undesirable. [0004]
  • Known technology has similarly limited the materials which can be delivered transvascularly, endoscopically, or via a conduit in conjunction with a laparoscope. Articles that are delivered by pushing and utilization of these devices are limited, typically, either to fluids or to relatively stiff solids. [0005]
  • The controlled release of drugs from polymer and from surgical suture is another therapeutic modality known in the art. Application of this technique, however, has hitherto required the insertion of suture using conventional methods of pulling the suture into the tissue, as by means of a sewing needle or tweezers, raising difficulties of access to the site of implantation. [0006]
  • SUMMARY OF THE INVENTION
  • The present invention expands the domain of materials that may be used for bulking as well as for other cellular and drug delivery applications. The invention allows for a filament, as defined below, to be introduced through a needle or other conduit, allowing such well-known biocompatible materials as those used in suture to be considered. With this novel advance, not only can the material have a bulking effect, but depending on the other properties of the filament used, it may add other mechanical attributes such as springiness, rigidity, flexibility, mass, orientation, and permeability. Further, the material being introduced may be a solid, compressed particulate or composite, thereby opening up a range of possible functions the material may perform such as drug delivery, radiation, chemotherapy or thermotherapy. The three-dimensional nature of the end result may be very appropriate to provide a scaffolding for cellular ingrowth for cells either injected with the filament, or those induced to grow into the matrix. [0007]
  • The device is capable of placing a significant amount of material in the body through a small portal, i.e., an opening in the body as defined below. This material may preloaded with a drug, or cells, or some other active material to produce some desired effect with the body. The dosage may be controlled by the length of the filament and the nature of the preloading, and may be modified at the time of delivery to the length of choice. Such a method may be useful for the delivery of subcutaneous heparin, insulin, contraceptive substances, and other pharmaceuticals useful for heart disease, smoking cessation, etc. The advantage of this approach over other subcutaneous drug delivery devices is its extremely low profile, and the ease in which it is positioned within any site in the body, in particular, in the proximity of the tissue to be affected. [0008]
  • In accordance with a preferred embodiment of the invention, a method is provided for modifying a tissue property of a subject, wherein the method consists of providing a quantity of filament, opening a portal in the body of the subject, where both “filament” and “portal” are defined below, inserting the filament through the portal into a region in the vicinity of the tissue, and localizing the filament in the region so as to modify the tissue property. The tissue property to be modified may include the mass, bulk, orientation, rigidity, flexibility, springiness, and permeability of the tissue. The filament is inserted directly, or with the aid of an endoscope or a laparoscope. Embodiments of the invention provide methods for bulking the tissue of a subject, coapting the walls of a vas, where “vas” is defined below, occluding a vas, preventing pregnancy, sterilizing a subject, clotting an ulcer, treating an aortic aneurism, treating a bleeding esophageal varix, providing chemotherapy, releasing a drug, catalyzing biochemical reactions, providing birth control, supporting cell growth in a subject, sewing body tissue, delivering anesthesia, and delivering a stent into a vas. Each of the aforesaid methods has the steps of providing a quantity of filament and inserting it into the body. The filament may be preloaded as described above. In further embodiments of the invention, a continuous length of filament may be severed to provide a desired length of filament within the body of the subject, and fluid may also be injected into the subject in conjunction with the filament. Additionally, in accordance with an alternate embodiment of the invention, suture is provided in particulate form, suspended in a liquid carrier to create a suture suspension, and inserted through a portal in the body of a subject to modify a tissue property that includes at least one of the mass, bulk, orientation, rigidity, flexibility, springiness, and permeability of the tissue. [0009]
  • In another embodiment of the invention, a method is provided for removing filament from a site in the body that consists of the steps of inserting a hollow shaft into the site, hooking the filament with a hooked tool, and withdrawing the filament via the hollow shaft. [0010]
  • In accordance with another aspect of the invention, a device is provided that has a conduit for insertion into a designated site in the body, and a feeding mechanism for supplying filament along the axis of the conduit in a manner such that support is provided across all lengths of the filament longer than three times the diameter of the filament. The conduit may be rigid, as well as semi-rigid or flexible. [0011]
  • In one embodiment of the invention, the feeding mechanism has an inner cannula with an inner diameter corresponding generally to the diameter of the filament and a mounting arrangement, which may be a coaxial outer cannula, for permitting the axial movement of the inner cannula. Finally, an actuator mechanism is provided for urging the inner cannula in axial reciprocation consisting of forward motion and retrograde motion with respect to the mounting arrangement. In alternate embodiments, the actuator mechanism may have a combination of grippers or a gripper and a brake. Additionally, the inner cannula may have distinct proximal and distal segments and a containment spring for retracting the distal segment toward the proximal segment during retrograde motion of the distal segment. [0012]
  • In further embodiments of the present invention, a tip may be provided on the mounting arrangement for penetrating body tissue, and a window may be provided proximally to the tip to allow filament to be fed into the site. Filament cutters are provided in several alternate embodiments to allow desired lengths of filament to be left in the body. In one filament cutter embodiment, a torquable head is disposed adjacent to the distal end of the conduit with a shearing surface disposed on at least one of the torquable head and the distal end of the conduit such that rotation of the torquable head severs the filament. In another filament cutter embodiment, a shearing surface is provided on at least one of the inner cannula and mounting arrangement of the device such that relative motion of the inner cannula and mounting arrangement cause shearing of the filament. [0013]
  • Other filament feeding mechanisms are provided in alternate embodiments of the invention which include conveyor belts engaged against the filament, a toothed wheel and idler wheel for advancing the filament, and a reciprocating shaft which drives the filament forward in the shaft and then springs back in disengagement from the filament. A motor may be employed for repetitively cycling the feeding mechanism. [0014]
  • In accordance with another aspect of the present invention, a device is provided for removing a filament from a site in the body where the device consists of a conduit and a hook for snagging and withdrawing the filament through the conduit.[0015]
  • BRIEF DESCRIPTION OF THE DRAWINGS
  • FIG. 1 is a schematic illustration of a filament injection device [0016] 1 in accordance with a preferred embodiment of the present invention.
  • FIG. 2 illustrates the principal components of a filament injection device in accordance with a preferred embodiment of the present invention. [0017]
  • FIGS. [0018] 3A-3C show cross-sectional views of a filament feeding mechanism in the advancement stage of a filament feeding cycle in accordance with the embodiment of the invention shown in FIG. 2.
  • FIGS. 4A and 4B show cross-sectional views of a filament feeding mechanism in a the reset stage of a filament feeding cycle in accordance with the embodiment of the invention shown in FIG. 2. [0019]
  • FIG. 5 shows an exploded view of a filament feeding mechanism according to an embodiment of the invention. [0020]
  • FIG. 6 is a cross-sectional view of the distal tip of a filament feeding mechanism in accordance with an embodiment, of the invention. [0021]
  • FIGS. 7A and 7B are cross-sectional views of the distal tip of FIG. 6, showing a filament cutting mechanism according to an embodiment of the invention. [0022]
  • FIG. 7C is a perspective view of the distal tip of a conduit in accordance with an embodiment of the invention showing an alternate filament cutting mechanism. [0023]
  • FIG. 7D is a cross-sectional view of the filament cutting mechanism of FIG. 7C. [0024]
  • FIG. 8 is a cross-sectional view of an filament feeding mechanism according to an alternate embodiment of the invention. [0025]
  • FIG. 9 is a schematic of a powered drive system for cycling the shaft [0026] 27 with the touch of a button.
  • FIG. 10 illustrates a layout of an alternative embodiment of the system. [0027]
  • FIG. 11A is a cross section of the result after the device has been used to coapt the walls of a tubular structure within the body. [0028]
  • FIG. 11B illustrates an embodiment of the invention for treatment of an ulcer. [0029]
  • FIG. 12 illustrates an embodiment of the invention for removing a filament in the body after it has been placed. [0030]
  • FIGS. [0031] 13A-13C illustrate use of the device of FIG. 1 for passing suture through and around tissue, and, in FIG. 13C, for creating a series of linked loops.
  • FIG. 14 illustrates the mechanism through which particle may be injected into the body in accordance with another embodiment of the invention. [0032]
  • FIGS. 15A and 15B show respectively a descended bladder of a female subject and the same bladder after it has been elevated by use of a filament implanted in accordance with an embodiment of the invention; [0033]
  • FIG. 16 shows an embolism that has been achieved in a blood vessel by means of a filament implanted in accordance with an embodiment of the invention; [0034]
  • FIG. 17 shows an aneurysm that has been filled by means of a filament implanted in accordance with an embodiment of the invention. [0035]
  • FIGS. 18 through 26 illustrate various embodiments of the invention for achieving the movement of a filament along a desired path so as to permit implantation of the filament; [0036]
  • FIGS. 18A and 18B illustrate an embodiment for achieving movement of a filament utilizing a pair of conveyor belts symmetrically engaged against the filament; [0037]
  • FIG. 19 illustrates an embodiment for achieving movement of a filament utilizing a toothed drive wheel against which the filament is engaged by an idler wheel; [0038]
  • FIG. 20 illustrates an embodiment, similar to that of FIG. 19, utilizing a toothed drive wheel against which the filament is engaged by an idler wheel, but wherein the filament is also engaged against the drive wheel by a guide having an arcuate surface that general conforms to the radius of the drive wheel; [0039]
  • FIGS. 21A and 21B illustrate and embodiment, similar to that of FIG. 19, utilizing a toothed drive wheel against which the filament is engaged by an idler wheel, but wherein the idler wheel is soft; [0040]
  • FIG. 22 illustrates an embodiment for achieving movement of a filament utilizing a toothed drive wheel against which the filament is engaged by a tubular guide; [0041]
  • FIGS. 23A and 23B illustrate an embodiment for achieving movement of a filament utilizing a drive wheel against which the filament is engaged by an idler belt; [0042]
  • FIGS. 24A through 24E illustrate an embodiment for achieving movement of a filament utilizing a pair of axially reciprocating tubular members, within which the filament is disposed, in conjunction with a periodically clamping finger; [0043]
  • FIGS. 25A through 25E illustrate an embodiment similar to that of FIGS. 24A through 24E but in which the coil springs of the latter figures are supplanted by complementary mating extensions of the tubular members; [0044]
  • FIGS. 26A and 26B illustrate an embodiment for achieving movement of a filament utilizing a pair of arms that are caused to reciprocate axially while being alternately opened and closed at the opposite ends of each stroke; [0045]
  • FIGS. 27A through 3 ID illustrate embodiments of the invention in which a region proximate to a tip of a cannula carrying a filament is provided with an arrangement, for cutting the filament, utilizing a concentrically disposed member and a window in both members through which the filament is placed and severed; [0046]
  • FIGS. 27A and 27B illustrate an embodiment wherein the outer member is pulled proximally with respect to the inner member to achieve cutting; [0047]
  • FIGS. 28A and 28B illustrate an embodiment wherein the outer member is pushed distally with respect to the inner member to achieve cutting; [0048]
  • FIGS. 29A through 29C illustrate an embodiment wherein the inner and outer members are rotated with respect to one another to achieve cutting; [0049]
  • FIGS. 30A through 30D illustrate the way a tip, having a cutting arrangement of one of the types described above, may be employed in conjunction with a suitable window to prevent the presentation of undue pressure, by the distal end of the filament, on tissue of the subject on whom the invention may be used; and [0050]
  • FIGS. 31A and 31B, and [0051] 32A and 32B, illustrate a possible configuration for a case for an embodiment similar to that of FIGS. 26A and 26B.
  • DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS
  • In order to provide an overall understanding of the present invention, the method, system, and device of the invention will be discussed with reference to the application of the invention to provide tissue bulking. However, it will be understood by persons of ordinary skill in the art that the general method, system, and device, described herein, are equally applicable to all cases in which filament injection would have value. A list of possible uses for the technology includes, but is not limited to, the injection of a filament-based system of drug delivery into tissue, the subcutaneous or interstitial injection of a filament for the purpose of bulking, shaping, applying pressure, or adding other mechanical properties (such as springiness or rigidity), and the injection of a filament to act as a matrix or lattice in which a cellular process may proceed (i.e. bone replacement, healing, implanted cellular scaffolding). [0052]
  • Other clinical uses include the injection into the body of a filament bearing other properties such as radiopacity, magnetism, radioactivity—radiation, or fluorescence, all suited for application as a clinical tracer or therapeutic agent. Similarly, the filament may have chemical properties which allow it to serve as a tracer of specified biochemical processes or as a catalyst to stimulate or enhance desired reactions within the tissue. This invention represents a new concept in the delivery and retrieval of mass as well as of therapeutic and diagnostic agents. [0053]
  • The applications of tissue bulking alone are manifold, once it is appreciated that tissue bulking may be achieved conveniently and at low risk using the method, system, and device of the present invention. Tissue bulking applications include, but are not limited to periurethral bulking of the urinary sphincter, support of the urethra, therapy of vesicourethral reflux, prevention of esophageal reflux via the gastroesophageal sphincter, and treatment of the anal sphincter for treatment of fecal incontinence. Other applications of tissue bulking which may be achieved using the present invention include the bulking of blood vessels, both internally or externally, in association with the treatment of bleeding ulcers. The applications listed are given by way of example, though it is to be understood that the scope of the invention is not limited to the applications listed but includes all applications wherein filamentous material is usefully injected into the body. [0054]
  • As used in this specification and in the claims hereto appended, a material, provided in a threadlike form, will be referred to as “flaccid” if its buckling stress, measured in units of force per unit cross-sectional area of the material, is less than or comparable to the shear strength that is typical of soft body tissue (such as the dermis). Shear strength is expressed in the same units as stress. Buckling stress, as is known in the mechanical arts, refers to the force per unit area applied axially to a member which causes deformation of the member in a direction orthogonal to the axis of the member. It is also known in the mechanical arts that the buckling stress of a member is proportional to the off-diagonal compressive modulus, (i.e., the ratio of axial compressive stress to the strain induced transverse to the axial direction) and inversely proportional to the square of the ratio of unsupported length to diameter of the member. Thus, the longer or finer a thread is, the less force per unit area is required to cause it to buckle. [0055]
  • Clearly, it is known that rigid, needle-shaped implements, such as all manner of needles or staples, may be driven into tissue upon application of sufficient axial force along the direction of insertion. By way of contrast, the present invention teaches a method of inserting materials which are flaccid rather than rigid. In view of the definition of “flaccid” provided above, flaccid materials are inherently incapable of being driven into tissue by the application of axial force. These materials are referred to, collectively, as “filament.” More particularly, as used in this specification and in the claims hereto appended, the term “filament” refers to a flaccid material, and may include biocompatible materials such as polypropylene, Nylon, DACRON.TM., polybutylester, polybutylethylene, polyglycolic acid (PGA), and variations thereof, and any other material, naturally occurring, biological, or man-made, which has been chosen for a particular application on the basis of biocompatibility, biodegradability, or any other desirable property. Other filament materials useful in particular clinical applications are composite, woven, or solid, and include silk, metal, ‘gut’, collagen, clastin, cartilage and bone. The term “filament” encompasses, particularly, all materials, such as polypropylene, currently supplied and used as suture material and referred to thereas. Additionally, the term “filament” encompasses the use of materials having shape memory, such as nitinol, which may be used to particular clinical advantage. Whereas many of the foregoing materials may be formed into a wire-shaped member that is not flaccid as defined herein, the term “filament” in this description and the accompanying claims is limited to the embodiment of such materials in their flaccid forms. [0056]
  • Since the “filament” is flaccid, it will be appreciated that materials of this category, if pressed, unguided, against the surface of body tissue, are likely to buckle rather than to cleave the surface, penetrate into the body tissue, or expand or dissect a space into the tissue. [0057]
  • When a filament is bent, such as under its own weight or due to compressive buckling, the inner regions yield under compression. Force applied to the distal end of a bent filament by driving it against a surface is no longer truly axial and has a vector component which leads to further bending. Plastic deformation may inhibit the return of the filament to the original configuration even after removal of the load. However, the filament need not undergo any plastic deformation if it is suitably introduced and trapped within the body tissue, in accordance with the present invention. [0058]
  • In the prior art, suture is treated as a flaccid material in that it is pulled through tissue, as by a needle or tweezers, rather than pushed. For suture or other filament sufficiently fine, large forces per unit cross-sectional area can be developed, using the teachings of the present patent, over small cross sectional areas. The force per unit area applied by the tip of the filament can readily exceed the shear strength of the body tissue so that the filament can thereby cleave and penetrate the tissue. The recognition of this ability of a filament, using the methods of this invention, to penetrate body tissue, enables the host of clinical applications which are described herein. [0059]
  • As used in this description and in the appended claims, a “portal” for insertion of filament into the body refers to any naturally existing or created opening into the body or a tissue. The invention teaches the insertion of filament into the vicinity of a tissue, where, as used in this description and in the appended claims, a “vicinity” includes at least a portion of the tissue itself, as well as its walls, and proximate tissue or body cavity. Since some tissues may be too small, fragile, or sensitive to permit direct insertion of filament, filament may be inserted, in accordance with the teachings of the present invention, into proximate tissue that is near but not directly associated with the target tissue. [0060]
  • Additionally, insertion of filament may be achieved via a vas, where, as used in this description and in the appended claims, the term “vas” refers to any duct, vessel, passageway or cavity occurring in the body, either by natural anatomical formation or through surgical intervention. [0061]
  • FIG. 1 illustrates a filament injection device [0062] 1 in accordance with a preferred embodiment of the present invention. Here a needle 6 is inserted through the skin 2 into the body 3. A small filament 5 is injected into an interstitial space 4. The needle 6 is attached to a housing 7 which has an inlet 11 for fluid, a fluid control 8 for fluid injection, an injection control 9 to advance the filament, and a cut control 10. Those skilled in the art will recognize that needle 6 may also be a rigid, flexible, deformable, malleable, semi-rigid or semi-flexible cannula or catheter inserted percutaneously, endoscopically or transvascularly. Further, filament 5 may also be a resorbable or non-resorbable suture, wire, or any of the other materials comprised within the definition of “filament” given above. This filament may be a composite material embedded with drugs, cells, or radioactive substances. The combination of drugs with polymer to provide programmed release of the drugs within the body is known, as described in A. Loh, Controlled Release of Drugs from Surgical Suture, 1987, which is herein incorporated by reference. The insertion into the body of a filament which has been preloaded with a therapeutic or diagnostic agent, whether by techniques of embedding or impregnating within the filament material or otherwise bonding to the filament, whether at the time of manufacture or at the time of insertion into the body, is included within the scope of the invention. While no other working channels are shown in the device, those skilled in the art will recognize that the modification of the device to permit additional instrumentation to be passed within or along-side the device does not depart from the invention. Such other channels may be provided for introducing energy guides, wires, endoscopic visualization devices or surgical tools. The device as shown would be easily advanced into the periurethral space for tissue bulking or drug delivery to treat incontinence, or the perivascular space for venous reconstitution or drug delivery, or the interstitial space within a tumor for chemotherapy, radiation or magnetic thermal therapy.
  • In this specification and in the appended claims, the term “distal” denotes the end of the filament injection device [0063] 1, or the end of any of the component parts of filament injection device 1 such as conduit 6, which is located toward the point of delivery of filament 5 into the body 3. Conduit 6 serves as the delivery cannula through which filament 5 is introduced into the body of the subject. Similarly, in this specification and in the appended claims, the term “proximal” denotes the end of the filament injection device 1 or the end of any of the component parts of filament injection device 1 which is located away from the point of delivery of filament 5 into the body 3. Because of the need to minimize the diameter of distal end 12 of filament injection device 1, in order to avoid leaving a large hole in the body 3 of the subject, the bulkier suture feeding mechanism typically resides in the bulkier proximal section 7 of the device. Therefore, the feeding mechanism, described below, cannot pull on the filament but must push it forward. In order to allow for pushing a flaccid material into the body, the zone between feeding mechanism 7 and conduit 6 over which filament 5 is unsupported must be kept to a minimum. In some preferred embodiments of the invention, there is no unsupported length of filament 5, while, in other embodiments, a length of filament 5 is unsupported, and is, typically, no larger than three times the characteristic diameter of the filament.
  • Referring now to FIG. 2, wherein the principal components of a filament feeding device used, in accordance with a preferred embodiment of the invention, to advance the filament into the tissue. Inner cannula [0064] 14 is a tubular section having a diameter closely matched to the diameter of filament 5 for which inner cannula 14 provides support. Inner cannula 14 prevents filament 5 from buckling or jamming as a result of the axial force pushing it into the body, and is, in turn, retained axially within a coaxial outer cannula 15. In alternate embodiments, inner cannula 14 may be retained by other manner of mounting arrangements, to include channels, as is well known to a person of ordinary skill in the art.
  • FIG. 3A shows a cutout window [0065] 16 in the proximal section of inner cannula 14. Cutout window 16 exposes a small section of filament 5 and allows actuating pad 17 to couple filament 5 and inner cannula 14 to an actuator mechanism 502 (shown in FIG. 5). Actuating pad 17 is referred to, functionally, as a “gripper.” FIG. 3B shows actuating pad 17 depressed in a direction 18 transverse to filament 5 in order to engage it securely. FIG. 3C shows the advancement, by means of the action of actuator mechanism 502 (shown in FIG. 5), of actuating pad 17 to the left, and the advancement, along with actuating pad 17, of both inner cannula 14 and filament 5 such that a length of filament 5 equal to the distance 19 of motion of actuating pad 17 is urged into the body tissue.
  • FIGS. 4A and 4B illustrate the next step of the filament feeding action, the reset part of the cycle, wherein actuating pad [0066] 17 is retracted from contact with filament 5 and is urged proximally, in retrograde direction 404, such that inner cannula 14 and actuating pad 17 return to their original proximal position. In a preferred embodiment of the invention, inner cannula 14 has a distal segment 408 and a proximal segment 410, separated by containment spring 412. The direction 406 of retraction of the distal segment 408 of inner cannula 14 is referred to as the retrograde direction. During the reset part of the filament feeding cycle, the filament 5 itself is prevented from coming back out of the body tissue by means of friction brake 402, located proximally to actuating pad 17, which secures filament 5 within the proximal segment 410 of inner cannula 14. Retraction of distal segment 408 of inner cannula 14 is achieved, in a preferred embodiment of the invention, by means of the force supplied by containment spring 412 in compression. The feeding action described allows a high force per unit cross-sectional area to be applied in advancing filament 5 into the body tissue while a lower force is supplied by containment spring 412 to retract the distal segment 408 of inner cannula 14.
  • Referring now to FIG. 5 wherein the components of a filament feeding mechanism, designated generally by numeral [0067] 500, are shown in exploded view. Actuator mechanism 502 is shown to comprise a thumb pad 504 which the physician uses to advance slider 506 forward to a stop in the slider guide 508. By pressing on distal part 505 of thumb pad 504, the physician causes activator pad 17 (shown in FIGS. 4A and 4B) to come into contact with filament 5 (shown in FIG. 4A), and, as he also urges thumb pad 504 forward, he feeds a discrete amount of filament 5, paid off of spool 510 along feed axis 512, into the body tissue, according to the mechanical principle described above with reference to FIG