BACKGROUND OF THE INVENTIONSutures are used within the human body during surgical operations. Sometimes flat braided sutures are used and sometimes they may cause post-operative irritation when the suture is implanted in a place or manner where repetitive sliding occurs. Sutures having higher coefficients of friction may sometimes lead to higher loads on the anchor sites as well as irritation where the suture is sliding, particularly if the suture is sliding on bone or cartilage.
Lower friction surfaces may be sought after in sutures in order to reduce irritation. One approach is to find more lubricious materials to use in the suture. Sutures that slide on hard surfaces are subject to wear and the resulting wear debris causes plowing and causes an increased frictional force. This can sometimes cause an undesirable amount of irritation for the patient and higher loads on anchor sites of the suture.
US2012197294 provides a textile yarn including a first segment and a second segment. The first segment includes a plurality of first strands and has a substantially constant first denier. The second segment includes a plurality of second strands integrated together and has a substantially constant second denier. There are more second strands in the second segment than first strands in the first segment such that the second denier is greater than the first denier. A first portion of the plurality of second strands is made from a first plurality of yarn elements that extend through the first and second segments. A second portion of the plurality of second strands is made from a second plurality of yarn elements present in the second segment and not the first segment. The yarn elements in the second plurality of yarn elements terminate in a transition zone between the first segment and the second segment.
WO2010100488 teaches a suture comprising an elongate tubular sheath formed from a plurality of braided yarn strands a plurality of axial yarn strands overlapping the braided yarn strands and aligned with the longitudinal axis of the elongate tubular sheath and transverse to the braided yarn strands and a core positioned within the tubular sheath, the core formed from a plurality of yarn strands extending longitudinally within the tubular sheath. Additionally, both axial and braided yarns may be incorporated within the suture having different denier. Different coloured yarn strands may also be incorporated within the outer tubular sheath to create repeating patterns along regions of the suture.
EP1543782 discloses a novel high tensile strength semi-absorbable composite suture with minimized non-absorbable mass. The suture has a core made from a bioabsorbable polymer. The core is covered by a braided sheath. The braided sheath is made from a nonabsorbable yarn and a bioabsorbable yarn. The bioabsorbable yarn is made from a least one filament of a bioabsorbable polymer. The nonabsorbable yarn is made from at least one filament of ultra high molecular weight polyethylene.
US2015173753 provides Surgical sutures are provided including a plurality of directional indicators that each visually indicate a same direction, e.g., a direction toward one free end of the suture. The directional indicators can be configured to indicate a position of the suture relative to a patient and/or other medical device(s). The directional indicators can be a function of the suture itself so as to be an integral part thereof. In other words, threads, also referred to as "strands," that form the suture can define the directional indictors. The suture can be braided using threads of two different colors so as to form the directional arrows as an integral part of the suture when the suture is braided in manufacturing of the suture.
EP 1844797 teaches braids and surgical devices made from yarns that include at least one filament made from a thermoplastic elastomer copolymer and at least one filament made from a polyolefin material.
US2010298872 discloses a surgical suture including a filamentary braid including filamentary elements projecting from the filamentary braid for anchoring in biological tissues.
Accordingly, it is desirable to provide a method and apparatus that provides a suture having a relatively low amount of sliding friction and therefore be less irritable to patients and reduced anchor sites of the suture.
SUMMARY OF THE DISCLOSUREThe foregoing needs are met, to a great extent, by the present disclosure, wherein in one aspect there is provided a dry sliding suture as defined in the appended independent claim 1. Preferred embodiments are defined in the dependent claims.
There has thus been outlined, rather broadly, certain embodiments of the invention in order that the detailed description thereof herein may be better understood, and in order that the present contribution to the art may be better appreciated. There are, of course, additional embodiments of the invention that will be described below and which will form the subject matter of the claims appended hereto.
In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of embodiments in addition to those described and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein, as well as the abstract, are for the purpose of description and should not be regarded as limiting.
As such, those skilled in the art will appreciate that the conception upon which this disclosure is based may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention.
DETAILED DESCRIPTIONThe various embodiments will now be described with reference to the drawing figures, in which like reference numerals refer to like parts throughout. An embodiment in accordance with the present disclosure provides a suture having and undulated surface. In some embodiments, the suture will be used in conditions where the suture may slide against a surface of greater or equal hardness as the suture, such as an implant, cartilage, or bone. In some embodiments, the way the suture is shaped and made may result in the design having a smaller coefficient of friction than a suture formed in a traditional manner regardless of the initial lubricity of materials used to form the suture in question.
An embodiment of the present inventive apparatus is illustrated inFIG. 1. FIG. 1 illustrates a partial top view of a suture 10. The suture 10 is made of two types of strands or ends 12 and 14 braided together to form a flat suture 10. The suture 10 includes a first end 12 and a second end 14.
In some embodiments, the ends 12 and 14 may be made of a variety of materials. For example, ultra-high-molecular-weight polyethylene (UHMWPE) may be used to make one or both of the ends 12 and 14. Alternatively one or both of the ends 12 and 14 may be made of polyester. The same suture 10 may include ends 12 and 14 of different materials such as, but not limited to UHMWPE and polyester. Using polyester in at least one of the ends 12 and 14 may give the suture 10 better knot security.
As shown inFIG. 1, the suture 10 has an undulated surface 15. The undulated surface 15 gives the suture 10 a lower coefficient of friction than a suture 10 of similar size and material with a flat surface in both dry and lubricated sliding conditions.
The undulated surface 15 has high portions 16 (shown by the lighter colored portions inFIG. 1) and low portions 18 (shown as the darker colored portions 18 inFIG. 1). The combination of the high portions 16 and the low portions 18 form a checkerboard pattern 20.
FIG. 2 is a side view of the portion of the suture 10 illustrated inFIG. 1. The undulated surface 15 of the suture 10 can clearly be seen. The first end 12 defines the high portions 16 and the second end 14 defines the low portions 18. The difference between the high portions 16 and the low portions 18 is illustrated by H1. In some embodiments, H1 is about 25-125 microns. Other differences in heights may also be used.
InFIGS. 1 and 2, L1 is shown to be the length between the high portions 16 and L2 is shown to be the length between the low portions 18. In some embodiments L1 is equal to L2. In other embodiments L1 and L2 are not equal. It is desirable to select the length of L1 and L2 so that they are not so long as to permit wear debris to move along with the suture 10 and cause plowing and increased friction. Keeping L1 and L2 (particularly L1) short, aids in reducing the likelihood of wear debris from being carried in the low portions 18 of the suture 10 and causing friction. In some embodiments, L1 and L2 are each in the range of 50-150 microns.
InFIG. 3 is a cross-section of the suture 10 illustrated inFIG. 1. The first group of ends 12 is shown to have a greater diameter than the second group of ends 14. The high portions 16 corresponds with the first end 12 and the low portion 18 corresponds with the second end 14. It is the difference in the diameters between the first ends 12 and the second end 14 which creates the undulated surface 15 which, as shown inFIG. 1, is in a checkerboard pattern 20.
In some embodiments, the Deniers of the two ends 12 and 14 are different which results in the two ends 12 and 14 having different diameters. In some embodiments, the first end 12 may have a Denier of 100 and the second end 14 may have a Denier of 55. In other embodiments, end 12 may be sized at 215 Denier and end 14 may be sized at 100 Denier. In other embodiments, the ends 12 and 14 may sized to have other Deniers. In some embodiments, the difference of the two sets of ends 12 and 14 may be 40 to 115 Denier.
FIGS. 4, 5, and 6 illustrate a second embodiment having similar views as those shown inFIGS. 1-3. The embodiments offigures 4, 5 and 6 are not encompassed by the wording of the claims but are considered as useful for understanding the invention.FIG. 4 illustrates a partial enlarged top view of a suture 10 having a first end 12 and second end 14. The suture 10 has an undulated surface 15 comprised of high portions 16 and low portions 18 which are represented by light and dark surfaces respectively. The light and dark surfaces representing the high portion 16 low portion 18 are set out in a checkerboard pattern 20 that is slightly different than that shown in the embodiment ofFIG. 1.
As can be seen inFIG. 4, the low portions 18 are smaller in size compared to the high portions 16. For example, L3 as shown inFIG. 4 represents the length of the low portion 18. L4 represents the length of the high portion 16. As shown inFIG. 4, L4 is longer than L3. In other embodiments, L4 may be longer than L4 or, alternatively, L3 and L4 may be similar in length. As a result, the embodiment shown inFIG. 4 is checkerboard like, but the "squares" of the checkboard are rectangular not square. For the reasons set forth above with respect to L1 and L2 inFigs. 1 and 2, it is desired to keep the length of L3 and L4 from being too long. In some embodiments L3 is in the range of 25-75 microns and L4 is in the range of 50-150 microns.
FIG. 5 is a partial side view of the suture 10 shown inFIG. 4. As can be seen inFIG. 5, the first end 12 corresponds with the high portion 16 and the second end 14 corresponds with the low portion 18. The high 16 and low portions 18 together form the undulated surface 15. The difference between the high portions 16 and the low portions 18 is illustrated by H2. In some embodiments, H2 is about 25-125 microns. In other embodiments, other differences in heights may also be used.
FIG. 6 is a cross-sectional view of the suture 10 taken along the line 6 - 6 inFIG. 4. The first end 12 and second end 14 are shown lined up next to each other. As can be seen inFIG. 6 the first end 12 and the second end 14 are roughly the same diameter. In such an embodiment, the first end 12 and the second end 14 may have the same Denier.
The ends 12 and 14 may be made of a variety of materials. For example, ultra-high-molecular-weight polyethylene (UHMWPE) may be used to make one or both of the ends 12 and 14. Alternatively one or both of the ends 12 and 14 may be made of polyester. The same suture 10 may include ends 12 and 14 of different materials such as, but not limited to UHMWPE and polyester. Using polyester in at least one of the ends 12 and 14 may give the suture 10 better knot security.
The undulated surface 15 illustrated inFIG. 4 is created where the two ends 12 and 14 are the same size fibers but the tightness of the braid has been altered. In some embodiments the two ends 12 and 14 may not exceed about 100 microns in diameter.
In some embodiments, the checkerboard like pattern 15 shown inFIG. 4 having high portions 16 and low portions 18 may be achieved by braiding ends 12 and 14 of same or similar diameter or Denier at a low braid angle with respect to the braiding machine bobbin. For example the braid may be formed tight enough so that the ends 12 and 14 are firmly in place and those are no gaps when handling bending or twisting the suture 10 by hand. Alternatively, the high portions 16 and low portions 18 forming the checkerboard like pattern 15 ofFIG. 4 may be achieved by having the all ends braided under different tensions.
While the illustrated figures only show two ends 12 and 14 and show the suture to only be four ends 12 and 14 wide, it should be understood that this has been simplified to better explain the various embodiments. It will be appreciated that some embodiments will use more or fewer ends 12 and 14 in the suture 10. Many sutures 10 will incorporate many more ends 12 and 14 than four in the braid of the suture 10. It may be appreciated that end 12 may represent all of the ends having the Denier or diameter of end 12 and end 14 may represent all of the ends having the Denier or diameter of end 14.
The many features and advantages of the invention are apparent from the detailed specification, and thus, it is intended to cover all such features and advantages of the invention which fall within the scope of the claims. Further, since numerous modifications and variations will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation illustrated and described, and accordingly, the scope of the invention is only limited by the scope of the appended claims.