US 3095017 A
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Description (OCR text may contain errors)
June 25, 1963 4 R. BLEILER ETAL 3,095,017
WOVEN ARTICLES Filed July 14, 1959 3 Sheets-Sheet 3 INVENTORS RICHARD BLEILER ROBERT M. HARRIES BY N RMAN C. JECKEL SAMUEL H. LA PORT GW ,M+
ATTORN VS fluoroethylene resin).
3,095,017 WOVEN ARTICLES Richard Bleiler and Robert M. Harries, Allentown, Pa, Norman C. Jeckel, Glens Falls, N.Y., and Samuel H. Lamport, Shaker Heights, Ghio, assignors to United States Catheter & Instrument Corporation, Glens Falls, N.Y., a corporation of New York Filed July 14, 1959, fier. No. 827,127 11 Claims. (Cl. 139-387) This invention relates to improvements in the weaving of articles and is more particularly concerned with weaving liquid-impervious bifurcated tubes to be used as blood vessel grafts or other prosthesis.
The recent expansion of vascular surgery has increased the need for blood vessel substitutes, particularly arteries, and artery banks have been established for this purpose. Homografts (natural blood vessels) have been used to a certain extent but such use is greatly restricted by limited supply, time and expense that is connected therewith. Since the supply of homografts is limited, it is extremely difiicult to match the varieties of size and shapes of blood vessels that may be necessary during surgery, the size of which may not be known prior to surgical entry.
The normal blood vessel is an extremely tough and resilient organ which must be flexible and elastic but at the same time strong and non-collapsible. The varied properties of the normal blood vessel is particularly emphasized at the joints, having an extensive range of movement, 'e.g., the hip joint between the legs and the primary body trunk. In fact, one of the common but difficult locations for blood vessel substitution has been the aortic bifurcation where the aorta divides into the iliac arteries to supply each leg.
It was only natural that attempts be made to secure synthetic blood vessels to be used on a surgical basis. Many materials have been suggested but nylon (polyhexamethylene adipamide) appears to be the first to have been utilized on a commercial basis. Since that time other materials have been developed or suggested, including Dacron (Dupont trademark for polyethylene glycol terephthalate), Orlon (Dupont trademark for polyacrylonitrile) and Teflon (Dupont trademark for tetra- Various other materials have been suggested, but these have been the leading ones.
Of these presently used materials, it has been found that Teflon causes the least tissue reactivity, retains greater strength over a period of time, heals more rapidly as a graft, exhibits a lower rate of thrombosis and occlusion and causes formation of a thinner fibrous layer in the internal bore, than any of the other materials. Thus, at the present time, Teflon is the preferred material.
There is a present and growing demand in vascular surgery for Woven bifurcated tubes that are impervious to blood and particularly for a Y-tube to be used at the aortic bifurcation into the iliac arteries. Not only must the weaving be dense enough to prevent leakage but the junction or crotch must be both strong and leakproof, as there is greater stress normally applied at this point.
It is an object of this invention to provide woven bifurcated tubes having common warp threads through- .out the single tube portion and the bifurcated portions.
It is also an object of this invention to provide tubing of the character described in a Y-shape which is densely ice woven and impermeable to blood for use as blood vessel prosthesis.
It is a further object of this invention to provide tubing of the character described which is leakproof and reinforced at the bifurcation junction.
We have found a tube may be continuously woven from common warp yarns having a single tube portion which bifurcates into two portions and that the junction or point of bifurcation may be reinforced if desired. The entire operation may be carried out continuously on narrow fabric looms, i.e., weaving the single tube portion, then weaving the two bifurcated portions and then returning to a single tube portion. The continuous unit is then cut to obtain the desired lengths of body and legs in the individual prosthesis units. We have also found that the density of the weaving is increased by applying variable tension to alternate warp filaments.
With these and other objects and features in view, the nature of which will be more .apparent, the invention will be more clearly understood by reference to the drawings, the accompanying detailed description and the appended claims.
In the drawings:
FIG. 1 is a sectional plan view of a tube woven in accordance with this invention which will form two Y- tubes when severed at line 12-42;
FIgICi. 2 is a transverse section taken at line 22 on FIG. 3 diagrammatically shows the position of yarns in the shed during a pick of the shuttle when weaving at the section of FIG. 2;
FIG. 4 diagrammatically shows the position of yarns in the shed during a subsequent pick of the shuttle when weaving at the section of FIG. 2;
FIG. 5 is a transverse section taken at line 55 on FIG. 1;
FIG. 6 diagrammatically shows the position of yarns in the shed during a pick of the shuttle when weaving .at the section of FIG. 5; 40
FIG. 7 diagrammatically shows the position of yarns in the shed during the return pick of the shuttle from FIG. 6;
FIG. 8 diagrammatically shows the position of the yarns in the shed during the subsequent pick of the shuttle from FIG. 7;
FIG. 9 is a transverse section taken at line 9-9 on FIG. 1;
FIG. 10 diagrammatically shows the position of the yarns in the shed during the picks of an associated pair of shuttles when weaving at the section of FIG. 9;
FIG. 11 diagrammatically shows the position of yarns during subsequent picks of the associated pair of shuttles when weaving at the section of FIG. 9;
FIG. 12- is a diagrammatic end view of a narrow fabric loom showing the path of warp yarns therethrough and particularly a drop weight system for applying tension to the warp;
FIG. 13 diagrammatically shows the path of the filling thread after weaving the section of FIG. 2;
FIG. 14 diagrammatically shows the path of the filling thread after weaving the section of FIG. 5; and
FIG. 15 diagrammatically shows the path of the filling thread after weaving the section of FIG. 9.
Referring to the drawings in detail, this invention as 3 illustrated is embodied in a Y-shaped woven tube for blood vessel replacement having common warp yarns throughout the body and legs and being reinforced at the point of bifurcation.
As shown in FIG. 1, there is a continuous woven unit 11 which will be cut along line 1212 to form two Y-tubes 13, each having a single lumen or body portion 14, double lumen or leg portions 16 and a reinforced junction area 17 forming a single-ply fabric, referred to as planar fabric portion in the claims in contrast to the tubular portions 13 and 14. The unit 11 can be woven on standard narrow fabric looms, modified as hereinafter described, continuously for as long as desired, switching from single to double lumen whenever desired to obtain the desired body and leg length.
Tubular ribbon is commonly woven in lIl'bbOIl mills on looms where the shuttle makes a pick in one direction through one ply of fabric and in the other direction through the associated and other ply of fabric. In other words, the ribbon is formed flat but of two plies in parallel and adjacent planes. Since the filling thread passes alternatively through the two plies, there is an endless fabric or tube, the lumen of which can be formed by separating the two plies.
In fact, the body 14 as shown in FIG. 1 is formed in the conventional manner which is further understood by reference to FIGS. 2 to 4 which represent sections through a loom shed transverse to, and thus showing the relative position of, the warp threads during the weaving operation. Line 18 shows the path and direction of the shuttle (and thus the filling thread) which is always at the same level. In FIG. 3, the shuttle has passed to the right through upper warp thread group 19 which represents the warp threads of the upper ply of the body or single lumen tubular portion 14. When the shuttle has reached the righthand position, the loom harness operates to lift the lower warp thread group 21 to the shuttle level (not shown) so that the shuttle returns through lower warp threads 21 which represent the lower ply of the body.
Both the upper and lower warp groups are further divided into two sub-groups, indicated at 22 and 23 for the upper warp and 24 and 26 for the lower warp. After the shuttle has returned to the left through lower warp threads 21, the loom harness lowers the upper warp threads 19 to shuttle level and also at the same time reverses the relative vertical position of groups 22 and 23, on the one hand, and 24 and 26 on the other, which is necessary to give a weaving pattern to the fabric. While at this position the shuttle passes to the right through the upper warp threads as shown in FIG. 4. With the shuttle at the right, the loom harness raises the lower warp threads 21 to shuttle level (not shown) with group '26 now spaced above 24 for the return throw of the shuttle. To this point, the operation of the loom in weaving the tubular ribbon (representing body 14) has been conventional.
It is necessary, however, to change to a double lumen arrangement to secure legs 16. Legs are defined herein as beginning when the body lumen divides into two lurnens. At a predetermined length, the operation of the loom harness is changed to that shown in FIGS. to 8 so that the upper warp group 27 has lost a group of threads at the center which joined with an associated group of threads from lower warp group 28 to form a fixed warp group 29 which always remains at shuttle level. Thus as shown in FIG. 6, during the shuttles pass to the right through the upper warp threads 27, the fixed warp threads 29 are also at shuttle level. In FIG. 7, for the return pass of the shuttle to the left, the lower warp group 28 has been raised to shuttle level but the fixed group 29 remained at shuttle level, however, reversing the vertical position of subgroups 31 and 32 in order to produce a weave pattern. In FIG. 8, on the next shuttle pass to the right the subgroups 33 and 34 of upper warp group 27 are again at shuttle level but reversed relative to each other to give a weaving pattern. At the same time, the fixed group 29 remains at shuttle level but has again reversed the vertical positions of subgroups 31 and 32. In other words, groups 31 and 32 remain at shuttle level for every pass but are vertically reversed for each successive pass. Immediately subsequent to the shuttle pass of FIG. 8, the shuttle will pass to the left but the lower warp group 28 will be at shuttle level wih subgroups 36 and 37 reversed (reversal shown in FIG. 8) from their relative positions shown in FIGS. 6 and 7. The fixed group 29 will, of course, remain at shuttle level but reversing subgroups 31 and 32 from the relative position of FIG. 8 to the same as shown in FIG. 7.
The weaving arrangement of FIGS. 6 to 8 is continued for approximately eight picks in the preferred embodiment, although it may 'be shorter, longer, or even con tinued indefinitely if there is a desire for a double lumen tube having an attached single-ply layer between the lumens. In fact, such a double lumen tube could be woven without regard to a single lumen, such as portion 14 or free legs (after cutting) such as 16. In the embodiment shown in FIG. 1, it will be appreciated, however, that the weaving arrangement just described for a relatively few picks leaves a one-ply fabric reinforcing area 17 which will serve to resist both rupture and leakage at this vital area in a blood vessel graft.
After termination of the reinforcing area, the loom harness operation is again changed to effect the thread movement shown in FIGS. 9 to 11 and a second shuttle is brought in operation to pass simultaneously to the right or left with the first one but at a lower plane. Thus as shown, there are now four major groups of thread, namely, the upper left group 38 subdivided into groups 39 and 41, the lower left group 42 subdivided into groups 43 and 44, the upper right group 46 subdivided into groups 47 and 48 and the lower right group 49 subdivided into groups 51 and 52. The upper shuttle path 50 is on the same plane as the earlier described path 18 and in fact the shuttle is the same. The lower shuttle path 55 represents a shuttle just brought into operation that effects a weaving path to the right and below path 50.
When upper left warp group 38 and upper right warp group 46 are at shuttle levels 50 and 55 respectively, the
two shuttles move to the right as shown in FIG. 10. Subsequently (not shown) the lower left warp group 42 and the lower right warp group 49 are lifted by the harness to the associated shuttle levels (groups 38 and 46 being simultaneously lifted above shuttle levels similar as upper warp group 27 in FIG. 7) and the shuttles pass to the left. With both shuttles at the left, the harness again places the upper left warp group 38 and the upper right warp group 46 at shuttle level but subgroups 41 and 48 are now respectively on top as seen in FIG. 11 so as to obtain a weaving pattern. Thereafter, the lower left warp group 42 and the lower right warp group 49 are brought to shuttle level (not shown) with subgroups 44 and 52, respectively, on top (as shown in FIG. 11). Thus two independent and separate tubes are being woven at this point but from warp threads common to the single tube earlier described. An equal division between the two tubes has been shown but an unequal division can be arranged if desired. Furthermore, it is obvious that more than two leg members can be woven in integral depending relation to the body if desired. When it is desired to return to weaving of the single tube portion, the procedure described hereinbefore is reversed.
From the foregoing description, it will be apparent that sixteen different harnesses are required to control the warp thread movements. Accordingly, the threads for each harness have been shown in a different cross-hatch design so that the individual threads can easily be traced through the various weaving steps shown in FIGS. 2 to 11. Although only one thread has been shown for certain harness groups, it will be appreciated that this is representative of a plurality of threads.
Harness warp threads 53 always appear from the left margin extending toward the center on the upper shed level, either above or below the imaginary shuttle path. Harness warp threads 54 appear similarly as 53 except that the two groups always appear in interchanging opposition to each other above or below the imaginary shuttle path. Harness warp threads 56 and 57 always appear from the left margin extending toward the center on the lower shed level and in opposition to each other above or below the imaginary shuttle path. Harness warp threads 58 and 59 always appear from the right margin extending toward the center on the upper shed level and in interchanging opposition to each other above or below the imaginary shuttle path.
Although as seen in FIGS. and 11, threads 58 and 59 are below all of the threads on the left side, it will be appreciated that 58 and 59 are still in the upper shed relative to the new shuttle path 55. Harness warp threads 61 and 62 always appear from the right margin extending toward the center on the lower shed level in interchanging opposition to each other above or below the imaginary shuttle path.
Harness warp threads 63 and 64 which generally appear in interchanging opposition to each other above or below the imaginary shuttle path appear on the right margin of the upper ply of the left leg in FIGS. 10 and 11, toward the center of the upper ply of the main body in FIGS. 3 and 4, and toward the left margin of the single reinforcing ply in FIGS. 6 to 8. Harness warp threads 66 and 67 generally appear in interchanging opposition to each other above or below the imaginary shuttle path on the right margin of the lower ply of the left leg in FIGS. 10 and 11, toward the center of the lower ply of the main body in FIGS. 3 and 4, and toward the left margin of the single reinforcing ply in FIGS. 6 to 8. Harness warp threads 68 and 69 generally appear in interchanging opposition to each other above or below the imaginary shuttle path on the left margin of the upper ply of the right leg in FIGS. 10 and 11, toward the center of the upper ply of the main body in FIGS. 3 and 4, and toward the right margin of the reinforcing single ply in FIGS. 6 to 8. Harness warp threads 71 and 72 generally appear in interchanging opposition to each other above or below the imaginary shuttle path on the left margin of the lower ply of the right leg in FIGS. 10 and 11, toward the center of the lower ply of the main body in FIGS. 3 and 4, and toward the right margin of the single reinforcing ply in FIGS. 6 to 8.
It is possible and within the scope of the invention to go directly from the single lumen weaving of FIGS. 2 to 4 to the double lumen of FIGS. 9 to ll without forming reinforced area 17. In such a case there may be a small opening which can be sealed with adhesive, molten thread material, clotted blood, etc.
The weaving pattern has been shown as a simple oneup-one-down pattern in either direction and is not considered an important feature.
It is necessary, of course, to secure a tight weave in blood Vessel work and it is preferred to have a higher density than heretofore woven in tubular ribbon processes. We have found that a significant and contributing factor to such a dense weave is providing a differential pressure or tension to alternative warp threads during the weaving process, i.e., every second warp thread going into a particular ply or wall of a tube, will have from about 5 to 30% less tension with about 20% being the preferred difference. With this variable tension on adjacent threads, a tighter wall can be woven. This variable tension feature is applicable to narrow fabric weaving generally, i.e., single and double ply, tubular and non-tubular bifurcated and straight, etc. The differential tension may be applied by various means other than the specific method described hereinafter.
FIG. 12 shows the diagrammatic cross-section of the path of travel of filaments through a ribbon loom 75. The warp spools 73 are placed on pins in the backracks 74 from which the individual threads 76 pass upwardly and over the top castle rolls 77 and thence down to the warp hanger rolls 78. The thread then again passes upwardly over the top castle rolls 77 and thence down under the glass rods 79 of the beam. The threads then pass through the harness and reeds (not shown) in the shed area 81 at the end of which the fabric is formed and is then rolled over the take-up rolls 82.
The differential tension is: applied to adjacent threads by placing different Weights on the carriers 84 provided at the warp hanger rolls 78.
For example, the normal tension applied is one pound per ten threads by way of the carriers to all threads but we apply 0.9 pound per ten threads by weights 83 and 1.1 pounds per ten threads by weights 86 which is applied to alternate threads between and adjacent the threads under tension of weights 83. The differential weights will be applied and adjusted, of course, so that adjacent warp threads in any given ply of fabric in the ribbon are under differential tension. Once the differential pressure is applied to the warp threads in the lo-om, no change is made when weaving the different parts of Y-tubes 13, which means that the reinforced junction area 17 which is a single ply will not have each adjacent warp thread under different tension as exists in the other single plies of the tubes. However, it is not important at that point.
This weaving operation as described may be applied to any type thread but the specific embodiment here is concerned with unbleached Teflon filaments of 200 and 400 denier (ail-though denier up to 2,400 feasible) which is preferred in the making of arterial grafts. A dense fabric is preferred for blood vessel work and approximately 90 warp and 70 filling threads are woven per inch in each ply when using 400 denier yarn of 6 turns per inch for the warp and 10 turns per inch for the filling. About 160 warp and iii-ling threads are woven per inch with 200 denier yarn of 10 turns per inch for warp and filling.
It is desirable after weaving of the tube to bleach the Teflon and also to corrugate the tubes, both of which may be done by processes not part of this invention.
1. An integral woven tubular member formed of warp and filler threads comprising a pair of longitudinally spaced body tube portions, a pair of parallel leg tube portions between said body tube portions and interconnected at their opposite ends to adjacent ends of said body tube portion, and a planar fabric portion at the juncture of each body tube portion and the adjacent ends of the pair of leg tube portions all warp threads extending and being woven throughout the entire length of said memher.
2. An integral woven bifurcated blood vessel prosthesis formed of warp and filler threads comprising a body tube, a pair of spaced generally parallel leg tubes joined to said body tube, said tubes having connecting lumens, and a planar fabric portion at the external junction of said tubes, all warp threads extending and being woven throughout the entire length of said prosthesis.
3. A prosthesis as claimed in claim 2 wherein said planar fabric portion is a single ply having warp threads common to said body and having filling thread-s common to said legs.
4. A prosthesis as claimed in claim 3 wherein said planar fabric portion has approximately eight common filling threads.
5. A prosthesis as claimed in claim 3 wherein said threads are tetrafiu oroethylene resin.
6. -A prosthesis as claimed in claim 5 wherein said threads are from about 200 to about 2,400 denier.
7. A prosthesis as claimed in claim 6 wherein said threads are 400 denier.
8. A prosthesis as claimed in claim 6 wherein said threads are 200 denier.
9. A prosthesis as claimed in claim 2 wherein adjacent warp threads in any tube were under difierent tensions during formation of said tubes, said difference being between 5 and 30%.
10. A prosthesis as claimed in claim 9 wherein said difference is approximately 20%.
11. A prosthesis as claimed in claim 10 wherein one group of warp threads were under about 0.09 pound tension per thread and the second group of threads adjacent and between the threads of said one group were under ab out 0.11 pound tension per thread.
References Cited in the file of this patent UNITED STATES PATENTS 462,040 Fox Oct. 27, 1891 1,157,755 Benjamin Oct. 26, 1915 2,194,038 Wallace Mar. 19, 1940 2,250,261 Goldsmith July 22, 1941 2,613,693 Jarvis Oct. 14, 1952 2,633,574 Dolan Apr. 7, 1953 2,797,712 Shapiro July 2, 1957 10 2,924,250 Sidebotham Feb. 9, 1960 OTHER REFERENCES Surgery, published by C. V. Mosby Company, St. Louis, Missouri (1955), Volume 37, pages 167-174.