Patent Application
20110264138
The present invention relates generally to filaments for surgical procedures, methods of manufacturing filaments for surgical procedures, and uses thereof.
Wound closure devices such as sutures, staples and tacks have been widely used in superficial and deep surgical procedures in humans and animals for closing wounds, repairing traumatic injuries or defects, joining tissues together (bringing severed tissues into approximation, closing an anatomical space, affixing single or multiple tissue layers together, creating an anastomosis between two hollow/luminal structures, adjoining tissues, attaching or reattaching tissues to their proper anatomical location), attaching foreign elements to tissues (affixing medical implants, devices, prostheses and other functional or supportive devices), and for repositioning tissues to new anatomical locations (repairs, tissue elevations, tissue grafting and related procedures) to name but a few examples.
Sutures are often used as wound closure devices. Sutures typically consist of a filamentous suture thread attached to a needle with a sharp point. Suture threads can be made from a wide variety of materials including bioabsorbable (i.e., that break down completely in the body over time), or non-absorbable (permanent; non-degradable) materials. Absorbable sutures have been found to be particularly useful in situations where suture removal might jeopardize the repair or where the natural healing process renders the support provided by the suture material unnecessary after wound healing has been completed; as in, for example, completing an uncomplicated skin closure. Non-degradable (non-absorbable) sutures are used in wounds where healing may be expected to be protracted or where the suture material is needed to provide physical support to the wound for long periods of time; as in, for example, deep tissue repairs, high tension wounds, many orthopedic repairs and some types of surgical anastomosis. Also, a wide variety of surgical needles are available, and the shape, and size of the needle body and the configuration of the needle tip is typically selected based upon the needs of the particular application.
To use an ordinary suture, the suture needle is advanced through the desired tissue on one side of the wound and then through the adjacent side of the wound. The suture is then formed into a “loop” which is completed by tying a knot in the suture to hold the wound closed. Knot tying takes time and causes a range of complications, including, but not limited to (i) spitting (a condition where the suture, usually a knot) pushes through the skin after a subcutaneous closure), (ii) infection (bacteria are often able to attach and grow in the spaces created by a knot), (iii) bulk/mass (a significant amount of suture material left in a wound is the portion that comprises the knot), (iv) slippage (knots can slip or come untied), and (v) irritation (knots serve as a bulk “foreign body” in a wound). Suture loops associated with knot tying may lead to ischemia (knots can create tension points that can strangulate tissue and limit blood flow to the region) and increased risk of dehiscence or rupture at the surgical wound. Knot tying is also labor intensive and can comprise a significant percentage of the time spent closing a surgical wound. Additional operative procedure time is not only bad for the patient (complication rates rise with time spent under anesthesia), but it also adds to the overall cost of the operation (many surgical procedures are estimated to cost between $15 and $30 per minute of operating time).
Self-retaining sutures (including barbed sutures) differ from conventional sutures in that self-retaining sutures possess numerous tissue retainers (such as barbs) which anchor the self-retaining suture into the tissue following deployment and resist movement of the suture in a direction opposite to that in which the retainers face, thereby eliminating the need to tie knots to affix adjacent tissues together (a “knotless” closure). Knotless tissue-approximating devices having barbs have been previously described in, for example, U.S. Pat. No. 5,374,268, disclosing armed anchors having barb-like projections, while suture assemblies having barbed lateral members have been described in U.S. Pat. Nos. 5,584,859 and 6,264,675. Sutures having a plurality of barbs positioned along a greater portion of the suture are described in U.S. Pat. No. 5,931,855, which discloses a unidirectional barbed suture, and U.S. Pat. No. 6,241,747, which discloses a bidirectional barbed suture. Methods and apparatus for forming barbs on sutures have been described in, for example, U.S. Pat. No. 6,848,152. Self-retaining systems for wound closure also result in better approximation of the wound edges, evenly distribute the tension along the length of the wound (reducing areas of tension that can break or lead to ischemia), decrease the bulk of suture material remaining in the wound (by eliminating knots) and reduce spitting (the extrusion of suture material—typically knots—through the surface of the skin. All of these features are thought to reduce scarring, improve cosmesis, and increase wound strength relative to wound closures using plain sutures or staples. Thus, self-retaining sutures, because such sutures avoid knot tying, allow patients to experience an improved clinical outcome, and also save time and costs associated with extended surgeries and follow-up treatments. It is noted that all patents, patent applications and patent publications identified throughout are incorporated herein by reference in their entirety.
The ability of self-retaining sutures to anchor and hold tissues in place even in the absence of tension applied to the suture by a knot is a feature that also provides superiority over plain sutures. When closing a wound that is under tension, this advantage manifests itself in several ways: (i) self-retaining sutures have a multiplicity of retainers which can dissipate tension along the entire length of the suture (providing hundreds of “anchor” points this produces a superior cosmetic result and lessens the chance that the suture will “slip” or pull through) as opposed to knotted interrupted sutures which concentrate the tension at discrete points; (ii) complicated wound geometries can be closed (circles, arcs, jagged edges) in a uniform manner with more precision and accuracy than can be achieved with interrupted sutures; (iii) self-retaining sutures eliminate the need for a “third hand” which is often required for maintaining tension across the wound during traditional suturing and knot tying (to prevent “slippage” when tension is momentarily released during tying); (iv) self-retaining sutures are superior in procedures where knot tying is technically difficult, such as in deep wounds or laparoscopic/endoscopic procedures; and (v) self-retaining sutures can be used to approximate and hold the wound prior to definitive closure. As a result, self-retaining sutures provide easier handling in anatomically tight or deep places (such as the pelvis, abdomen and thorax) and make it easier to approximate tissues in laparoscopic/endoscopic and minimally invasive procedures; all without having to secure the closure via a knot. Greater accuracy allows self-retaining sutures to be used for more complex closures (such as those with diameter mismatches, larger defects or purse string suturing) than can be accomplished with plain sutures.
A self-retaining suture may be unidirectional, having one or more retainers oriented in one direction along the length of the suture thread; or bidirectional, typically having one or more retainers oriented in one direction along a portion of the thread, followed by one or more retainers oriented in another (often opposite) direction over a different portion of the thread (as described with barbed retainers in U.S. Pat. Nos. 5,931,855 and. 6,241,747). Although any number of sequential or intermittent configurations of retainers are possible, a common form of bidirectional self-retaining suture involves a needle at one end of a suture thread which has barbs having tips projecting “away” from the needle until the transition point (often the midpoint) of the suture is reached; at the transition point the configuration of barbs reverses itself about 180° (such that the barbs are now facing in the opposite direction) along the remaining length of the suture thread before attaching to a second needle at the opposite end (with the result that the barbs on this portion of the suture also have tips projecting “away” from the nearest needle). Projecting “away” from the needle means that the tip of the barb is further away from the needle and the portion of suture comprising the barb may be pulled more easily through tissue in the direction of the needle than in the opposite direction. Put another way, the barbs on both “halves” of a typical bidirectional self-retaining suture have tips that point towards the middle, with a transition segment (lacking barbs) interspersed between them, and with a needle attached to either end.
Despite the multitude of advantages of unidirectional and bidirectional self-retaining sutures, there remains a need to improve upon the design of the suture such that a variety of limitations can be eliminated and enhanced and/or additional functionality is provided.
In accordance with one aspect, the present invention provides heterofunctional sutures and self-retaining sutures having sections of suture filament with different features.
In accordance with another aspect, the present invention provides heterofunctional sutures and self-retaining sutures having visible/recognizable indicia associated therewith to facilitate the identification and differentiation of sections of suture filament having different features.
In accordance with another aspect, the present invention provides heterofunctional sutures and self-retaining sutures having machine-readable indicia associated therewith to facilitate the identification and differentiation of sections of suture filament having different features.
In accordance with another aspect, the present invention provides sutures and self-retaining sutures having visible or machine-readable indicia associated therewith which are indicative of conditions of the suture filament such as tension.
In accordance with another embodiment, the present invention provides heterofunctional sutures having machine-readable markers indicative of features or conditions of the suture and/or sections of the suture.
In accordance with another embodiment, the present invention provides heterofunctional sutures having markers indicative of features or conditions of the suture and/or sections of the suture that may be read through non-optical means.
In accordance with another embodiment, the present invention provides heterofunctional sutures having active markers indicative of features or conditions of the suture and/or sections of the suture.
In accordance with particular embodiments the marked heterofunctional sutures are bidirectional self-retaining sutures.
In accordance with other embodiments, the present invention provides methods and devices for use in conjunction the above sutures.
The details of one or more embodiments are set forth in the description below. Other features, objects and advantages will be apparent from the description, the drawings, and the claims. In addition, the disclosures of all patents and patent applications referenced herein are incorporated by reference in their entirety.
Features of the invention, its nature and various advantages will be apparent from the accompanying drawings and the following detailed description of various embodiments.
a and 9b are partial elevation views of self-retaining sutures according to the present invention having transition segment indentations.
a and 10b are partial elevation views of self-retaining sutures according to the present invention having transition segment relief forms.
Definitions of certain terms that may be used hereinafter include the following.
“Self-retaining system” refers to a self-retaining suture together with devices for deploying the suture into tissue. Such deployment devices include, without limitation, suture needles and other deployment devices as well as sufficiently rigid and sharp ends on the suture itself to penetrate tissue.
“Self-retaining suture” refers to a suture that comprises features on the suture filament for engaging tissue without the need for a knot or suture anchor.
“Tissue retainer” (or simply “retainer”) or “barb” refers to a physical feature of a suture filament which is adapted to mechanically engage tissue and resist movement of the suture in at least one axial directions. By way of example only, tissue retainer or retainers can include hooks, projections, barbs, darts, extensions, bulges, anchors, protuberances, spurs, bumps, points, cogs, tissue engagers, traction devices, surface roughness, surface irregularities, surface defects, edges, facets and the like. In certain configurations, tissue retainers are adapted to engage tissue to resist movement of the suture in a direction other than the direction in which the suture is deployed into the tissue by the physician, by being oriented to substantially face the deployment direction. In some embodiments the retainers lie flat when pulled in the deployment direction and open or “fan out” when pulled in a direction contrary to the deployment direction. As the tissue-penetrating end of each retainer faces away from the deployment direction when moving through tissue during deployment, the tissue retainers should not catch or grab tissue during this phase. Once the self-retaining suture has been deployed, a force exerted in another direction (often substantially opposite to the deployment direction) causes the retainers to be displaced from the deployment position (i.e. resting substantially along the suture body), forces the retainer ends to open (or “fan out”) from the suture body in a manner that catches and penetrates into the surrounding tissue, and results in tissue being caught between the retainer and the suture body; thereby “anchoring” or affixing the self-retaining suture in place. In certain other embodiments, the tissue retainers may be configured to permit motion of the suture in one direction and resist movement of the suture in another direction without fanning out or deploying. In certain other configurations, the tissue retainer may be configured or combined with other tissue retainers to resist motion of the suture filament in both directions. Typically a suture having such retainers is deployed through a device such as a cannula which prevents contact between the retainers and the tissue until the suture is in the desired location.
“Retainer configurations” refers to configurations of tissue retainers and can include features such as size, shape, flexibility, surface characteristics, and so forth. These are sometimes also referred to as “barb configurations”.
“Bidirectional suture” refers to a self-retaining suture having retainers oriented in one direction at one end and retainers oriented in the other direction at the other end. A bidirectional suture is typically armed with a needle at each end of the suture thread. Many bidirectional sutures have a transition segment located between the two barb orientations.
“Transition segment” refers to a retainer-free (barb-free) portion of a bidirectional suture located between a first set of retainers (barbs) oriented in one direction and a second set of retainers (barbs) oriented in another direction. The transition segment can be at about the midpoint of the self-retaining suture, or closer to one end of the self-retaining suture to form an asymmetrical self-retaining suture system.
“Suture thread” refers to the filamentary body component of the suture. The suture thread may be a monofilament, or comprise multiple filaments as in a braided suture. The suture thread may be made of any suitable biocompatible material, and may be further treated with any suitable biocompatible material, whether to enhance the sutures' strength, resilience, longevity, or other qualities, or to equip the sutures to fulfill additional functions besides joining tissues together, repositioning tissues, or attaching foreign elements to tissues.
“Monofilament suture” refers to a suture comprising a monofilamentary suture thread.
“Braided suture” refers to a suture comprising a multifilamentary suture thread. The filaments in such suture threads are typically braided, twisted, or woven together.
“Degradable suture” (also referred to as “biodegradable suture” or “absorbable suture”) refers to a suture which, after introduction into a tissue is broken down and absorbed by the body. Typically, the degradation process is at least partially mediated by, or performed in, a biological system. “Degradation” refers to a chain scission process by which a polymer chain is cleaved into oligomers and monomers. Chain scission may occur through various mechanisms, including, for example, by chemical reaction (e.g., hydrolysis, oxidation/reduction, enzymatic mechanisms or a combination of these) or by a thermal or photolytic process. Polymer degradation may be characterized, for example, using gel permeation chromatography (GPC), which monitors the polymer molecular mass changes during erosion and breakdown. Degradable suture material may include polymers such as polyglycolic acid, copolymers of glycolide and lactide, copolymers of trimethylene carbonate and glycolide with diethylene glycol (e.g., MAXON™, Tyco Healthcare Group), terpolymer composed of glycolide, trimethylene carbonate, and dioxanone (e.g., BIOSYN™ [glycolide (60%), trimethylene carbonate (26%), and dioxanone (14%)], Tyco Healthcare Group), copolymers of glycolide, caprolactone, trimethylene carbonate, and lactide (e.g., CAPROSYN™, Tyco Healthcare Group). A dissolvable suture can also include partially deacetylated polyvinyl alcohol. Polymers suitable for use in degradable sutures can be linear polymers, branched polymers or multi-axial polymers. Examples of multi-axial polymers used in sutures are described in U.S. Patent Application Publication Nos. 20020161168, 20040024169, and 20040116620. Sutures made from degradable suture material lose tensile strength as the material degrades. Degradable sutures can be in either a braided multifilament form or a monofilament form.
“Non-degradable suture” (also referred to as “non-absorbable suture”) refers to a suture comprising material that is not degraded by chain scission such as chemical reaction processes (e.g., hydrolysis, oxidation/reduction, enzymatic mechanisms or a combination of these) or by a thermal or photolytic process. Non-degradable suture material includes polyamide (also known as nylon, such as nylon 6 and nylon 6,6), polyester (e.g., polyethylene terephthlate), polytetrafluoroethylene (e.g., expanded polytetrafluoroethylene), polyether-ester such as polybutester (block copolymer of butylene terephthalate and polytetra methylene ether glycol), polyurethane, metal alloys, metal (e.g., stainless steel wire), polypropylene, polyethelene, silk, and cotton. Sutures made of non-degradable suture material are suitable for applications in which the suture is meant to remain permanently or is meant to be physically removed from the body.
“Suture diameter” refers to the diameter of the body of the suture. It is to be understood that a variety of suture lengths may be used with the sutures described herein and that while the term “diameter” is often associated with a circular periphery, it is to be understood herein to indicate a cross-sectional dimension associated with a periphery of any shape. Suture sizing is based upon diameter. United States Pharmacopeia (“USP”) designation of suture size runs from 0 to 7 in the larger range and 1-0 to 11-0 in the smaller range; in the smaller range, the higher the value preceding the hyphenated zero, the smaller the suture diameter. The actual diameter of a suture will depend on the suture material, so that, by way of example, a suture of size 5-0 and made of collagen will have a diameter of 0.15 mm, while sutures having the same USP size designation but made of a synthetic absorbable material or a non-absorbable material will each have a diameter of 0.1 mm. The selection of suture size for a particular purpose depends upon factors such as the nature of the tissue to be sutured and the importance of cosmetic concerns; while smaller sutures may be more easily manipulated through tight surgical sites and are associated with less scarring, the tensile strength of a suture manufactured from a given material tends to decrease with decreasing size. It is to be understood that the sutures and methods of manufacturing sutures disclosed herein are suited to a variety of diameters, including without limitation 7, 6, 5, 4, 3, 2, 1, 0, 1-0, 2-0, 3-0, 4-0, 5-0, 6-0, 7-0, 8-0, 9-0, 10-0 and 11-0.
“Needle attachment” refers to the attachment of a needle to a suture requiring same for deployment into tissue, and can include methods such as crimping, swaging, using adhesives, and so forth. The suture thread is attached to the suture needle using methods such as crimping, swaging and adhesives. Attachment of sutures and surgical needles is described in U.S. Pat. Nos. 3,981,307, 5,084,063, 5,102,418, 5,123,911, 5,500,991, 5,722,991, 6,012,216, and 6,163,948, and U.S. Patent Application Publication No. US 2004/0088003). The point of attachment of the suture to the needle is known as the swage.
“Suture needle” refers to needles used to deploy sutures into tissue, which come in many different shapes, forms and compositions. There are two main types of needles, traumatic needles and atraumatic needles. Traumatic needles have channels or drilled ends (that is, holes or eyes) and are supplied separate from the suture thread and are threaded on site. Atraumatic needles are eyeless and are attached to the suture at the factory by swaging or other methods whereby the suture material is inserted into a channel at the blunt end of the needle which is then deformed to a final shape to hold the suture and needle together. As such, atraumatic needles do not require extra time on site for threading and the suture end at the needle attachment site is generally smaller than the needle body. In the traumatic needle, the thread comes out of the needle's hole on both sides and often the suture rips the tissues to a certain extent as it passes through. Most modern sutures are swaged atraumatic needles. Atraumatic needles may be permanently swaged to the suture or may be designed to come off the suture with a sharp straight tug. These “pop-offs” are commonly used for interrupted sutures, where each suture is only passed once and then tied. For barbed sutures that are uninterrupted, these atraumatic needles are preferred.
Suture needles may also be classified according to the geometry of the tip or point of the needle. For example, needles may be (i) “tapered” whereby the needle body is round and tapers smoothly to a point; (ii) “cutting” whereby the needle body is triangular and has a sharpened cutting edge on the inside; (iii) “reverse cutting” whereby the cutting edge is on the outside; (iv) “trocar point” or “taper cut” whereby the needle body is round and tapered, but ends in a small triangular cutting point; (v) “blunt” points for sewing friable tissues; (vi) “side cutting” or “spatula points” whereby the needle is flat on top and bottom with a cutting edge along the front to one side (these are typically used for eye surgery).
Suture needles may also be of several shapes including, (i) straight, (ii) half curved or ski, (iii) ¼ circle, (iv) ⅜ circle, (v) ½ circle, (vi) ⅝ circle, (v) and compound curve.
Suturing needles are described, for example, in U.S. Pat. Nos. 6,322,581 and 6,214,030 (Mani, Inc., Japan); and 5,464,422 (W.L. Gore, Newark, Del.); and 5,941,899; 5,425,746; 5,306,288 and 5,156,615 (US Surgical Corp., Norwalk, Conn.); and 5,312,422 (Linvatec Corp., Largo, Fla.); and 7,063,716 (Tyco Healthcare, North Haven, Conn.). Other suturing needles are described, for example, in U.S. Pat. Nos. 6,129,741; 5,897,572; 5,676,675; and 5,693,072. The sutures described herein may be deployed with a variety of needle types (including without limitation curved, straight, long, short, micro, and so forth), needle cutting surfaces (including without limitation, cutting, tapered, and so forth), and needle attachment techniques (including without limitation, drilled end, crimped, and so forth). Moreover, the sutures described herein may themselves include sufficiently rigid and sharp ends so as to dispense with the requirement for deployment needles altogether.
“Needle diameter” refers to the diameter of a suture deployment needle at the widest point of that needle. While the term “diameter” is often associated with a circular periphery, it is to be understood herein to indicate a cross-sectional dimension associated with a periphery of any shape.
“Armed suture” refers to a suture having a suture needle on at least one suture deployment end. “Suture deployment end” refers to an end of the suture to be deployed into tissue; one or both ends of the suture may be suture deployment ends. The suture deployment end may be attached to a deployment device such as a suture needle, or may be sufficiently sharp and rigid to penetrate tissue on its own.
“Wound closure” refers to a surgical procedure for closing of a wound. An injury, especially one in which the skin or another external or internal surface is cut, torn, pierced, or otherwise broken is known as a wound. A wound commonly occurs when the integrity of any tissue is compromised (e.g., skin breaks or burns, muscle tears, or bone fractures). A wound may be caused by an act, such as a puncture, fall, or surgical procedure; by an infectious disease; or by an underlying medical condition. Surgical wound closure facilitates the biological event of healing by joining, or closely approximating, the edges of those wounds where the tissue has been torn, cut, or otherwise separated. Surgical wound closure directly apposes or approximates the tissue layers, which serves to minimize the volume new tissue formation required to bridge the gap between the two edges of the wound. Closure can serve both functional and aesthetic purposes. These purposes include elimination of dead space by approximating the subcutaneous tissues, minimization of scar formation by careful epidermal alignment, and avoidance of a depressed scar by precise eversion of skin edges.
‘Tissue elevation procedure” refers to a surgical procedure for repositioning tissue from a lower elevation to a higher elevation (i.e. moving the tissue in a direction opposite to the direction of gravity). The retaining ligaments of the face support facial soft tissue in the normal anatomic position. However, with age, gravitational effects and loss of tissue volume effect downward migration of tissue, and fat descends into the plane between the superficial and deep facial fascia, thus causing facial tissue to sag. Face-lift procedures are designed to lift these sagging tissues, and are one example of a more general class of medical procedure known as a tissue elevation procedure. More generally, a tissue elevation procedure reverses the appearance change that results from effects of aging and gravity over time, and other temporal effects that cause tissue to sag, such as genetic effects. It should be noted that tissue can also be repositioned without elevation; in some procedures tissues are repositioned laterally (away from the midline), medially (towards the midline) or inferiorly (lowered) in order to restore symmetry (i.e. repositioned such that the left and right sides of the body “match”).
“Medical device” or “implant” refers to any object placed in the body for the purpose of restoring physiological function, reducing/alleviating symptoms associated with disease, and/or repairing and/or replacing damaged or diseased organs and tissues. While normally composed of biologically compatible synthetic materials (e.g., medical-grade stainless steel, titanium and other metals or polymers such as polyurethane, silicon, PLA, PLGA and other materials) that are exogenous, some medical devices and implants include materials derived from animals (e.g., “xenografts” such as whole animal organs; animal tissues such as heart valves; naturally occurring or chemically-modified molecules such as collagen, hyaluronic acid, proteins, carbohydrates and others), human donors (e.g., “allografts” such as whole organs; tissues such as bone grafts, skin grafts and others), or from the patients themselves (e.g., “autografts” such as saphenous vein grafts, skin grafts, tendon/ligament/muscle transplants). Medical devices that can be used in procedures in conjunction with the present invention include, but are not restricted to, orthopedic implants (artificial joints, ligaments and tendons; screws, plates, and other implantable hardware), dental implants, intravascular implants (arterial and venous vascular bypass grafts, hemodialysis access grafts; both autologous and synthetic), skin grafts (autologous, synthetic), tubes, drains, implantable tissue bulking agents, pumps, shunts, sealants, surgical meshes (e.g., hernia repair meshes, tissue scaffolds), fistula treatments, spinal implants (e.g., artificial intervertebral discs, spinal fusion devices, etc.) and the like.
As discussed above, the present invention provides compositions, configurations, methods of manufacturing and methods of using sutures, heterofunctional sutures and self-retaining sutures in surgical procedures which eliminate a variety of limitations and provide enhanced and/or additional functionality. As used herein, a heterofunctional suture is a suture having two or more functionally distinct sections of suture filament where the sections of filament have different features. A heterofunctional suture may also encompass sutures having two or more sections of filament where devices associated with the sections of filament, such as a needle by way of example only, have different features. As used herein the term “feature” is used to refer to a fixed property of a suture, such as material, retainer orientation, nominal diameter, needle configuration etc. The term “condition” is used to refer to variable properties of a suture filament such as tension, temperature etc. The term property is used to encompass both features (fixed properties) and conditions (variable properties) of sutures. The two or more sections of suture filament in a heterofunctional suture need not be of any particular length, but a section should be long enough for its difference in property to have an effect on the functionality of the section. This typically requires a length of suture long enough for at least one pass or bite through tissue under the conditions of use. Typically “a section of suture” will be a portion of suture having a length at least two orders of magnitude larger than the diameter and more typically, three or four orders of magnitude larger than the diameter of the suture.
In accordance with particular embodiments, the present invention provides sutures and self-retaining sutures which are dual-armed sutures; triple-armed sutures; multiple-armed sutures; heterofunctional sutures having two or more sections of suture having different features; dual-arm sutures having different types (or sizes) of needles on each end; single or dual-armed sutures for use with different layers/depth and types of tissue; single or dual armed sutures with sections of filament having different diameters for use with different layers/depth and types of tissue; dual-armed sutures having asymmetrically placed transition sections; and sutures having a combination of two or more of these features. According to particular embodiments of the present invention, these sutures, self-retaining sutures and/or sections thereof may be unmarked, marked or differentially-marked by one or more types of markers or combination of markers. Marked sutures include by way of example, dual-armed sutures having different markers on each end of the suture; heterofunctional sutures having different markers on different sections of suture; self-retaining sutures having markers indicative of the presence, absence and/or orientation of retainers in a section of suture; dual-armed sutures having different markers on each needle; dual-armed sutures having markers to identify orientation or direction of an end of a dual armed suture; sutures having markers utilized in robotically assisted surgical tools and with endoscopic surgical tools; sutures having markers that identify types and characteristics of sutures and call up such data from tables in computer devices (computer-assisted surgery devices) which display that information for the doctor or limit what the doctor can do as far as tensioning the suture as deployed; and sutures having markers in combination with sound or variable sound generators or light or variable light generators or haptic devices that vary a stimulus provided to a physician depending on the stress, strain and/or tension on the sutures.
In addition to marked sutures for facilitating the doctor's use of the suture during a surgical procedure, sutures disclosed herein include ones with markers that can be used for identifying sections of a heterofunctional suture after it is has been deployed and the surgical procedure completed. For example, markers detectable by computed tomography or computed axial tomography can assist in the locating of suture well after the patient has healed from the surgical procedure.
The markers may be provided on the suture or on a needle or on another device associated with a suture or section of suture for example a pledget or the like. The markers include, but are not limited to: markers which identify features of the suture such as materials and/or other fixed properties; markers which identify conditions of the suture such as tension and/or other variable properties; markers visible in the visible light frequency range; markers invisible to the naked eye but which are visualized under the conditions of surgical use; markers recognizable in the non-visible radiation frequency range, such as in the ultraviolet or other fluorescence spectra; markers detectable with ultrasound; markers detectable by x-ray radiation; markers detectable by magnetic resonance imaging; markers detectable by computed tomography (CT) scans or by computed axial tomography (CAT) scans; markers which are machine readable; markers which may be read remotely; markers which are active markers; markers which are passive markers (passive RFID); markers which include an LED and an accelerometer or strain sensor; markers which include a light source and a sensor responsive to conditions of the suture; markers which identify the presence, absence and/or orientation of retainers; markers which identify different sections of a suture having different features; markers which change color due to suture stress, strain and/or tension; markers with alternating colors where the colors blend and produce a different color in response to suture stress, strain and/or tension; strain and/or tension; markers with different colors placed at different depths or side by side where the colors blend and produce a different color in response to suture stress, strain and/or tension; markers having one or more patterns where the patterns interfere with each to produce a visible or recognizable change in pattern in response to suture stress, strain and/or tension; markers which span a stretchable suture body and a relatively not stretchable retainer (somewhat isolated from the body) such that there is a noticeable misalignment when the suture body is under stress and stretched; and markers which deform or change configuration when the suture is under stress; markers which extend from housings or sleeves or cavities in the needle or suture when the suture is under stress; markers useful with stereo/3D imaging devices.
A break is shown in each of sections 140, 142, 144, 146 and 148 to indicate that the length of each section may be varied and selected depending upon the application for which the suture is intended to be used. For example, transition section 144 can be asymmetrically located closer to needle 110 or needle 112, if desired. A self-retaining suture having an asymmetrically located transition section 144 may be favored by a physician that prefers to use his dominant hand in techniques that require suturing in opposite directions along a wound. The physician may start further from one end of the wound than the other and stitch the longer portion of the wound with the needle that is located further from the transition section 144. This allows a physician to use his dominant hand to stitch the majority of the wound with the longer arm of the suture. The longer arm of the suture is that section of suture between the transition section and the needle which is located further from the transition section.
Heterofunctional self-retaining suture system 100 is composed of two arms having different functions. Each arm may be considered to be a section of self-retaining suture system 100. The first arm comprising sections 142 and section 140 of self-retaining suture thread 102 and a curved needle 110 has relatively small retainer suitable for engaging harder/denser tissue. The second arm comprising sections 146 and 148 and needle 112 of self-retaining suture thread 102 has relatively larger retainers suitable for engaging softer/less dense tissue. Self-retaining suture thread 102 of
The physician wishes to move the transition section 144 so that it is approximately centered upon opening 160 and then pick up needle 112 and take another bite through the tissue on each side of opening 160 moving from right to left. However, the retainers 130 along are not sufficiently visible to the physician via the endoscope. Also, endoscopic instruments 166 and 168 do not provide enough tactile sensation to the physician for the physician to be able to feel where the retainers 130 are located.
The first task for the physician is how to identify section 144, differentiate it from sections 142 and 146 and then center section 144 upon opening 160. If section 144 is provided with markers 154, as shown in
The next task for the physician is finding and identifying the needle associated with the suture exiting on the right side of the opening 160. Note that section 142 of the suture which is located on the right of opening 160 leaves visual field 164. Everything outside the dashed circle is invisible to the physician without moving the endoscope. Unless needle 112 is marked in some way, the physician may assume, incorrectly that needle 112 is associated with section 142 of self-retaining suture system 100. However, if needle 112 is marked as shown in
The next task for the physician is to find and grasp needle 110. One way for the physician to acquire needle 110 is to follow section 142 of the suture all the way from opening 160 to the end. This is time consuming and the physician maybe come confused if sections 142 and 146 cross or move at some point. A faster technique would be for the physician to start from the visible segment 170 of section 142 of the suture within the visual field 164. However, unless section 142 of the suture thread is marked in some way there is no way for the physician to be sure that visible segment 170 of the suture is part of section 142. Likewise the physician cannot tell whether visible segment 172 of the suture is part of section 142 or part of section 146. If section 142 is marked in some way, the physician may acquire section 142 at visible portion 170. If section 142 is marked in a way that indicates orientation of the suture the physician will be able also to know in what direction needle 110 lies from the visible portion 170 allowing the physician to acquire the needle 110 in the most expedient and accurate way. If needle 110 is also marked in some way, the physician may confirm that the physician has acquired the correct needle for the next step in the procedure. Thus, marking the suture, suture sections and/or needles reduces error and saves time.
As discussed above, it is particularly desirable to mark and identify portions of a self-retaining system when there is a difference in the features/utility of different sections of the self-retaining suture. In the case of self-retaining sutures the difference in features between sections of the suture may be the presence, absence and orientation of retainers associated with the section. In
As shown in
As shown in
The difference in function between the arms in a bidirectional self-retaining suture system may be due to differences in the needles (or other devices attached to the filament) rather than the suture filament itself. For example, as shown in
Heterofunctional self-retaining suture systems are not limited to two arms (dual-armed suture). A heterofunctional self-retaining suture system may have more than two arms. Other multiple-arm sutures may include two, three, four, five or more arms. As shown in
Referring now to
Referring now to
As discussed above, it is particularly desirable to mark and identify portions of a heterofunctional suture system where different sections of the suture have different features such as in dual-arm self-retaining suture systems. In heterofunctional self-retaining suture systems the difference in function between sections of the suture may be the presence, absence and/or orientation of retainers. To serve the purpose of allowing a physician to identify and differentiate suture sections, the suture markers should be readily recognized and distinguished by the physician under the conditions in which the suture is to be used. For example, in microsurgery applications, markers may be used that are visible under the microscope, but not necessarily visible to the naked eye. Likewise in endoscopic applications, markers should be used that are visible through the endoscope and associated display system. If the suture will be used with fluoroscopic visualization then the markers may include radiopaque markers. If the suture will be used with ultrasound visualization then the markers may include echogenic markers. Thus, different markers and different types of markers may be appropriate under different circumstances depending upon the circumstances of the procedure and the scanning/imaging/visualization technology utilized in the procedure.
The markers can be provided in various forms that may be identified and distinguished from one another. The markers may comprise distinguishable, patterns, shapes, lengths, colors sizes, directions and arrangements. The markers can include different colors such as red, green, orange, yellow, green, blue etc. Such colors may be used in a uniform density or varying density in which case the graduation of color density may be used to designate e.g. an orientation. The markers may be included along the entire length of the self-retaining suture system, at a number of discrete points, or only at the ends or transition section of the self-retaining suture. In some cases it may be desirable to use a color for markers that is uncommon in the operative environment. For example, it may be desirable to use green markers because green is not common in the human body. In endoscopic applications using green is advantageous because the video system can be programmed to emphasize green and enhance marker visualization without interfering with the remainder of the image.
The markers can be formed by various conventional methods. For example, the markers can be coated, sprayed, glued, dyed, stained, or otherwise affixed to the self-retaining suture systems or components thereof. Traditional colourant application processes include, without limitation, dipping, spraying (by, for example, an ink jet), painting, printing, applying and/or coating colourants on the suture section of interest. Critical fluid extraction (such as carbon oxide) may also be used to add colourant locally to all or part of the section desired to be marked. Alternatively, colourant(s) for the suture section of interest may be included in a portion of the suture material that is used to form the suture body, wherein that portion is in the section of interest of the manufactured suture.
Additionally, the suture section of interest can be demarcated by using an energy-activated colourant. For example, when a laser-activated colourant (that is, a pigment or dye which permanently changes colour after being exposed to laser energy) is used to colour the suture, then the suture section of interest can be demarcated by using laser energy to permanently change the suture coating in the suture section of interest. This also applies to using other energy activated colourants which are activated by other energy sources such as, but not limited to, heat, chemicals, microwaves, ultraviolet light, or x-rays. For example, bleaching chemicals such as sodium hypochlorite or hydrogen peroxide will permanently change the colourant's colour which allows for the demarcation of the suture section of interest. The marking of the suture section of interest may be one or more mechanical tabs. This tab can be made from both absorbable or non-absorbable materials. For example, a non-absorb tab made from polyester felt or polytetrafluoroethylene felt can be used as the transition marker were the surgeon gently pulls and removes the tab from the suture once the suture section of interest is position in the tissue prior to completing the tissue closure of the wound. The removal of the tab can be facilitated by having a cut or slice partially through the tab for ease of removal during surgery. Examples of absorbable materials include glycolide and glycolide-lactide polymers. The configuration of the tab includes, but not limited to, a rectangle tab, a circular tab, or a spiral tab. For example, but not limited to, the tab can be affixed to the suture with a hole were the suture passes through the tab, a partial cut/slice where the suture is positioned in the tab slice, by folding the table around the suture, by crimping the tab to the suture, by twisting the tab around the suture, by tying the tab to the suture, or by adhesion (e.g., ultrasonic welding, adhesive “gluing”, thermal welding, and the like) to the suture, The use of an absorbable tab can be especially useful for deep cavity tissue closures where the surgeon may choose to leave the absorbable tab inside the body.
Additionally, the mechanical tab can be coloured to improve the visibility of the tab to mark the suture section of interest. This includes, but not limited to, using fluorescent colourants, radio detectable compounds, or magnetic resonance imaging detectable compounds.
Additionally, the colourant(s) employed for demarcating the suture section of interest may be included on a plastic biocompatible material which is applied on the suture at the section of interest. Such a layer may be absorbable, such as polyglycolide coating which has a colourant to mark the suture section of interest, or it may be a non-absorbable material, such silicone. The coloured material may be synthetic or may be derived from a natural source (whether the material be modified or unmodified), such as collagen. The plastic biocompatible material may be applied to the suture before or after the retainers are formed on the suture body.
Alternatively, the suture section of interest may be reverse-marked, such that where the suture body is already visibly coloured, the colourant may be absent from all or part of the suture section of interest such that at least a portion of the section of interest is optically distinguishable by the surgeon from the rest of the suture. Such a suture may manufactured by including a colourant-free portion of suture material in the suture section of interest area during the manufacture of the suture body (for example, by extrusion) or by removal of colourant from the suture section of interest after the suture body has been manufactured, whether before or after retainers have been formed on the suture body. Colourant may be removed locally by, for example, critical fluid extraction such as (e.g., carbon oxide). It is not necessary to remove all of the colourant from the section of interest of the suture as long as there is a difference detectible by a surgeon between the section of interest and the rest of the suture.
Another example of a reverse-marked suture is one that lacks a coloured layer that is present on the rest of the suture body. A plastic biocompatible material bearing a colourant may be applied on the other sections of the suture, and at least where the other sections border the section of interest. Examples of such materials are discussed above. As in the foregoing examples, demarcating the suture section of interest may be effected in the suture manufacturing process either before or after forming retainers.
Another example of a reverse-marked suture is one having a coaxial structure wherein each coaxial layer having a different colour, and a portion of the outermost layer(s) is removed to visually expose a layer below. For example, a dual-layer monofilament polypropylene suture can be produced with a white inner core (intercoaxial layer) with a blue outer coaxial layer, and portions of the outer layer can be removed to visually expose the white inner monofilament to mark the suture section of interest.
Yet another example of a reverse-marked suture is one in which an external coating is removed (or partially removed) from the suture in the suture section of interest, and where either the coating or base suture has a contrasting colour difference. This technique of removing (or partially removing) material in the suture section of interest may also create a tactile demarcation of the suture section of interest.
The marking may include a radio-detectable compound or magnetic resonance imaging detectable compound. For example a suture section of interest provided with barium sulfate (BaSO4), such as by impregnating the suture with barium sulfate or adding a coating containing barium sulfate, will be detectable by electromagnetic energy. In the case of x-ray detection, the barium sulfate marked section of interest would be radiopaque. Likewise, computed tomography (CT) scans or computed axial tomography (CAT) scans can be used to detect the radio detectable section of interest. The use of electromagnetic energy for radio detection of the transition section is not limited to using x-ray wavelengths as other radio frequencies may be used. Likewise, gadolinium (Gd) or gadolinium compounds can be used for the marking of the suture section of interest especially when the detection will be done by using magnetic resonance imaging (MRI). The use of radio detectable or magnetic resonance imaging detectable marking of the transition zone may be useful to the surgeon during laparoscopic surgical procedures.
Alternatively, markers can be made by treating a surface of the suture system to make an visually observable change in surface characteristics such as by branding, texturing, embossing, stamping and the like. Alternatively, the markers may be an integral part of the material from which the self-retaining suture system is formed—such as by forming a self-retaining suture system by joining different sections of suture filament of different colors. The markers may be provided on one or more of the suture filament, the needles, or another item, such as a pledget, associated with the self-retaining suture system or section of the filament. In some case markers may be formed as an integral part of the retainers of a self-retaining suture, such as by creating retainers of a particular color of material or by exposing a particular color of material—different retainer patterns may be used to differentiate different sections of the self-retaining suture.
The shapes of
As described above, the needle or another object associated with a section of a heterofunctional suture filament may be marked to enable that section to be identified and distinguished from other sections instead of, or in addition to, marking the suture filament itself.
Visual/recognizable markers may be used for other functions instead of, or in addition to, identifying and differentiating sections of a heterofunctional suture and indicating the orientation of the suture. Markers may also be utilized to indicate other features or conditions of the suture. A marker indicative of a fixed feature such as the material from which the suture is made could be in the form of a color code or the like that provides a visual/recognizable clue to the physician regarding the suture he is using without having to check the packaging. Non-sterile portions of the suture packaging may be removed by a physician's assistant, for example, with the physician observing or not observing the labeling. Thus, a fixed marker associated with the suture may be useful for the physician to confirm that they are using the suture they requested. Again, the marker can provide an image in the visible and/or non-visible light range.
A marker that is indicative of a condition of the suture must undergo a discernible change in appearance or other recognizable characteristic in response to a change in the condition. For example, in endoscopic applications where long instruments are used through ports or even operated remotely, it can be difficult or impossible for the physician to feel the tension applied to the suture by the instruments or by the suture to tissue. To replace the reduced or missing haptic feedback, it is advantageous to provide a variable marker indicative of the tension in the suture. The variable marker provides a visual or recognizable cue that can be observed by the physician through the endoscope (or recognized by other means).
In a simple case, as shown in
An alternative self-retaining suture filament 510 is shown in
For example, markers can be made of two colors that under stress blend and present a third color or various intensities of shades of a different color depending upon the degree of stress. The two different colors can be placed at different depths of a suture and when the suture is stressed the colors blend or overlap each other to present different colors. The different depths of the suture can be made of different materials that stretch to different degrees when the suture is stressed and thus the different colors at different depths would blend or overlap each other to present a different color. The different levels can be co-extruded to provide, as desired, each layer with different types of suture material and different colored markers. Further the different colored markers can be placed side by side on the surface of the suture and when the suture is under stress the colors blend or overlap or become differently oriented relative to each other such that they present a different color or shade and the color or shade may be dependent upon the degree of stress that the suture is under. Instead of different colors, different patterns can be used and then the patterns overlap or otherwise combine due to stress being placed on the suture, a different pattern such as an interference or interfering pattern can be presented.
An alternative self-retaining suture filament 520 is shown in
As shown in
Other passive mechanical sensors may indicate suture properties through means other than displaying a visible marker or optically detectable marker. For example, a wireless passive strain sensor may be incorporated into a suture or a needle or another device associated with the suture to allow remote sensing of the tension using a non-optical sensor. One such sensor is disclosed in Tan et al., “A wireless, passive strain sensor based on the harmonic response of magnetically soft materials” Smart Materials And Structures 17:1-6 (2008) which is incorporated herein by reference. Tan et al. disclose a sensor made of a ferromagnetic sensing element separated by a deformable elastic material from a permanent magnetic strip. Adjusting the strain applied to the sensor changed the distance between the sensor and the permanent magnet by deforming the elastic material. This change in distance created a detectable change in the harmonic response of the sensor to an alternating magnetic field. Thus a simple passive sensor provides a strain signal that can be detected remotely using an external magnetic field. Similarly passive strain sensors associated with the suture or needle can be read using other remote sensing technologies, such as ultrasound, fluoroscopy, and the like.
Fixed or variable markers for suture filaments may also be provided by active systems instead of, or in addition to, other marking methods. Such active visible markers may be utilized to indicate features or conditions of the suture.
Light source 618 is controlled by light controller 617 which takes power from power source 616. Light controller 617 determines the characteristics of the light signal provided by light source 618. The light signal may be varied over time such as by turning it on, turning it off and/or flashing at different speeds. The light signal may also be varied in color if light source 618 is capable of producing light of different wavelengths. If power source 616 is a battery, the available power will limit the time that light source 618 may be operated. Thus, it will be desirable that light source 618 be activated by light controller 617 only at the beginning of the procedure utilizing suture filament 610. The activation may be achieved using a magnetic switch, mechanical switch, electromagnetic sensor or the like. In one embodiment, the light source can be an LED and the controller a sensor that measures stress, strain or tension. The LED and sensor can be made in a semiconductor chip. The power supply can be passive, such as in a passive RFID tag. Then a source of radiation may activate the RF power source to power the sensor and the LED light source. In some embodiments the sensor may comprise an accelerometer.
In a dual-armed suture system, another active marker system 614 may be provided in another needle swaged to the opposite end of suture filament 610. Where two active marker systems 614 are used, they may be differentiated based upon the characteristics of the light signals provided by the light source 618. For example, each light source may be controlled to provide light of a different wavelength than the other. Alternatively, one light source may provide a constant light signal whereas the other light source may provide a flashed light signal. If light signals from both light sources overlap in the suture filament, then the light signals may be attenuated by adjusting the power of the light signals, reducing the light transmission of the suture filament or placing a barrier such as an opaque section to block light transmission between one section of suture filament 610 and another section of suture filament 610.
An active marker indicative of a feature, such as the material of which a section of a heterofunctional suture is made, or the orientation of retainers in a particular section of a self-retaining suture, can be in the form of a color code or the like that provides a visual cue to the physician regarding the suture he is using without having to check the packaging. Non sterile portions of the suture packaging may be removed by a physician's assistant for example with the physician observing the labeling. Thus an active visible marker associated with the suture may be useful for the physician to confirm they are using the suture they requested.
Active visual markers may also be utilized to indicate conditions of the suture. An active visual marker that is indicative of a condition of the suture undergoes an observable change in appearance in response to the condition. Thus, in one example a light signal may be modulated in response to tension in a suture providing a visual cue that can be observed by the physician.
The light signal provided by light source 628 is modulated by controller 627 in response to the output of sensor 625. Thus the light signal provided by light source 628 is modulated in response to the condition monitored by sensor 625. For example, sensor 625 may be a force sensor, such as an accelerometer, and controller 627 (also part of the accelerometer, for example, in this embodiment) may control light source 628 so that no light signal is provided to suture filament 620 until the sensor indicates that a threshold tension in filament 620 has been achieved. When the tension passes the threshold then controller 627 turns on light source 628 providing a cue to the physician. Alternatively, the light source may be on initially and then flashed when the tension reaches the threshold.
As shown in
Where an active marker system is provided other than at the end of a suture filament as shown in
As described above, a suture filament may be provided with visible markers indicative of features or conditions of the suture filament and/or indicative of particular sections of a suture filament having different features. Such markers are observed by the physician under the operative conditions—which may include e.g. magnification in microsurgical procedures and video display—including wavelength translation/enhancement in endoscopic procedures. However, where machines are available to read, scan and decode suture markers, such markers need not be visible markers or markers that may be visually decoded. The markers may be designed to be machine-readable instead of, or in addition to, being directly visualizable by the physician. While visible markers may be identified and decoded utilizing a video tracking and analyzing system, different visible markers may be more suitable for machine recognition. Moreover, non-visible suture markers or coding may also be used by a computer system to identify sections and conditions of sutures. When the suture sections and/or conditions have been recognized and assessed by the system, information about the sections and conditions of the suture may be provided to the physician by the system. The information may be provided to the physician over any available display system, including a visual, aural or haptic display.
As shown in
As shown in
As shown in
In the embodiments of
As shown in
Referring again to
Display processing system 748 of
Where a surgical procedure is being performed manually or by sufficiently sensitive robotically-assisted means, tactile markings may be provided; these may be particularly useful in sutures that are not self-retaining and in the retainer-free sections of self-retaining sutures. For example, in the case of self-retaining sutures, the doctor may wish to identify the transition segment; accordingly, the such as the transition segment may be provided with a configuration that is more easily detectible by touch than the simple absence of retainers, thereby obviating the surgeon's need to repeatedly and/or vigorously feel along the suture body to locate the transition segment. Such tactile markings may be provided in any section of interest of a suture, and may include a deformation in the section of interest, such as deformation 804 of transition segment 802 in suture 800 shown in
Easily detectible indentations in the section of interest may also be provided, such as by compression (e.g., stamping) of all or part of the section to deform the suture material therein, and by removal of suture material (e.g., cutting, etching, abrading, laser removal) from all or part of the suture section of interest to create an indentation. Indentations may take any form (such as, without limitation, grooves, wells, dents), as long as the diameter of the suture body at the indentation is less than the diameter of the suture body elsewhere, and as long as the diameter of suture body at the indentation remains sufficient to withstand breakage from forces normally exerted during suture deployment and engagement. For example, an indentation or narrowing of the suture diameter at the transition segment may assist a doctor in locating the transition segment. Referring to
Other examples of tactile suture markings include a tactilely detectible increase in the diameter of the suture body at all or part of the section of interest. For example, protrusions on the surface of the section of interest that are easily detectable and distinguishable from tissue retainers may assist a surgeon in locating the section of interest, such as those protrusions 1004 in transition segment 1002 on suture 1000 in
Other forms of tactile demarcations include texture differences. Providing texture differences to all or part of the transition segment includes providing a plurality of areas of increased and/or decreased suture body diameter in the section of interest. For example, a plurality of indentations, a plurality of relief configurations, and any combinations thereof may be provided in the section of interest, by methods including, without limitation, compression, cutting, coating, application of agents such as abrasives, polymerisers, acid etchants, base etchants, and so forth.
Suture threads described herein may be produced by any suitable method, including without limitation, injection molding, stamping, cutting, laser, extrusion, and so forth. With respect to cutting, polymeric thread or filaments may be manufactured or purchased for the suture body, and the retainers can be subsequently cut onto the suture body; the retainers may be hand-cut, laser-cut, or mechanically machine-cut using blades, cutting wheels, grinding wheels, and so forth. During cutting either the cutting device or the suture thread may be moved relative to the other, or both may be moved, to control the size, shape and depth of cut 210. Particular methods for cutting barbs on a filament are described in U.S. patent application Ser. No. 09/943,733 titled “Method Of Forming Barbs On A Suture And Apparatus For Performing Same” to Genova et al., and U.S. patent application Ser. No. 10/065,280 titled “Barbed Sutures” to Leung et al. both of which are incorporated herein by reference. The sutures may be made of any suitable biocompatible material, and may be further treated with any suitable biocompatible material, whether to enhance the sutures' strength, resilience, longevity, or other qualities, or to equip the sutures to fulfill additional functions besides joining tissues together, repositioning tissues, or attaching foreign elements to tissues.
Additionally, self-retaining sutures described herein may be provided with compositions to promote healing and prevent undesirable effects such as scar formation, infection, pain, and so forth. This can be accomplished in a variety of manners, including for example: (a) by directly affixing to the suture a formulation (e.g., by either spraying the suture with a polymer/drug film, or by dipping the suture into a polymer/drug solution), (b) by coating the suture with a substance such as a hydrogel which will in turn absorb the composition, (c) by interweaving formulation-coated thread (or the polymer itself formed into a thread) into the suture structure in the case of multi-filamentary sutures, (d) by inserting the suture into a sleeve or mesh which is comprised of, or coated with, a formulation, or (e) constructing the suture itself with a composition. Such compositions may include without limitation anti-proliferative agents, anti-angiogenic agents, anti-infective agents, fibrosis-inducing agents, anti-scarring agents, lubricious agents, echogenic agents, anti-inflammatory agents, cell cycle inhibitors, analgesics, and anti-microtubule agents. For example, a composition can be applied to the suture before the retainers are formed, so that when the retainers engage, the engaging surface is substantially free of the coating. In this way, tissue being sutured contacts a coated surface of the suture as the suture is introduced, but when the retainer engages, a non-coated surface of the retainer contacts the tissue. Alternatively, the suture may be coated after or during formation of retainers on the suture if, for example, a fully-coated rather than selectively-coated suture is desired. In yet another alternative, a suture may be selectively coated either during or after formation of retainers by exposing only selected portions of the suture to the coating. The particular purpose to which the suture is to be put or the composition may determine whether a fully-coated or selectively-coated suture is appropriate; for example, with lubricious coatings, it may be desirable to selectively coat the suture, leaving, for instance, the tissue-engaging surfaces of the sutures uncoated in order to prevent the tissue engagement function of those surfaces from being impaired. On the other hand, coatings such as those comprising such compounds as anti-infective agents may suitably be applied to the entire suture, while coatings such as those comprising fibrosing agents may suitably be applied to all or part of the suture (such as the tissue-engaging surfaces). The purpose of the suture may also determine the sort of coating that is applied to the suture; for example, self-retaining sutures having anti-proliferative coatings may be used in closing tumour excision sites, while self-retaining sutures with fibrosing coatings may be used in tissue repositioning procedures and those having anti-scarring coatings may be used for wound closure on the skin. As well, the structure of the suture may influence the choice and extent of coating; for example, sutures having an expanded segment may include a fibrosis-inducing composition on the expanded segment to further secure the segment in position in the tissue. Coatings may also include a plurality of compositions either together or on different portions of the suture, where the multiple compositions can be selected either for different purposes (such as combinations of analgesics, anti-infective and anti-scarring agents) or for their synergistic effects.
In addition to the general wound closure and soft tissue repair applications, self-retaining sutures can be used in a variety of other indications.
Self-retaining sutures described herein may be used in various dental procedures, i.e., oral and maxillofacial surgical procedures and thus may be referred to as “self-retaining dental sutures.” The above-mentioned procedures include, but are not limited to, oral surgery (e.g., removal of impacted or broken teeth), surgery to provide bone augmentation, surgery to repair dentofacial deformities, repair following trauma (e.g., facial bone fractures and injuries), surgical treatment of odontogenic and non-odontogenic tumors, reconstructive surgeries, repair of cleft lip or cleft palate, congenital craniofacial deformities, and esthetic facial surgery. Self-retaining dental sutures may be degradable or non-degradable, and may typically range in size from USP 2-0 to USP 6-0.
Self-retaining sutures described herein may also be used in tissue repositioning surgical procedures and thus may be referred to as “self-retaining tissue repositioning sutures”. Such surgical procedures include, without limitation, face lifts, neck lifts, brow lifts, thigh lifts, and breast lifts. Self-retaining sutures used in tissue repositioning procedures may vary depending on the tissue being repositioned; for example, sutures with larger and further spaced-apart retainers may be suitably employed with relatively soft tissues such as fatty tissues.
Self-retaining sutures described herein may also be used in microsurgical procedures that are performed under a surgical microscope (and thus may be referred to as “self-retaining microsutures”). Such surgical procedures include, but are not limited to, reattachment and repair of peripheral nerves, spinal microsurgery, microsurgery of the hand, various plastic microsurgical procedures (e.g., facial reconstruction), microsurgery of the male or female reproductive systems, and various types of reconstructive microsurgery. Microsurgical reconstruction is used for complex reconstructive surgery problems when other options such as primary closure, healing by secondary intention, skin grafting, local flap transfer, and distant flap transfer are not adequate. Self-retaining microsutures have a very small caliber, often as small as USP 9-0 or USP 10-0, and may have an attached needle of corresponding size. The microsutures may be degradable or non-degradable.
Self-retaining sutures as described herein may be used in similarly small caliber ranges for ophthalmic surgical procedures and thus may be referred to as “ophthalmic self-retaining sutures”. Such procedures include but are not limited to keratoplasty, cataract, and vitreous retinal microsurgical procedures. Ophthalmic self-retaining sutures may be degradable or non-degradable, and have an attached needle of correspondingly-small caliber.
Self-retaining sutures can be used in a variety of veterinary applications for a wide number of surgical and traumatic purposes in animal health.
Although the present invention has been shown and described in detail with regard to only a few exemplary embodiments of the invention, it should be understood by those skilled in the art that it is not intended to limit the invention to the specific embodiments disclosed. Various modifications, omissions, and additions may be made to the disclosed embodiments without materially departing from the novel teachings and advantages of the invention, particularly in light of the foregoing teachings. Accordingly, it is intended to cover all such modifications, omissions, additions, and equivalents as may be included within the spirit and scope of the invention as defined by the following claims.
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/US09/44274 | 5/16/2009 | WO | 00 | 5/9/2011 |
| Number | Date | Country | |
|---|---|---|---|
| 61053912 | May 2008 | US |
