Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B17/00—Surgical instruments, devices or methods
  • A61B17/064—Surgical staples, i.e. penetrating the tissue
  • A61B17/0644—Surgical staples, i.e. penetrating the tissue penetrating the tissue, deformable to closed position

Definitions

• This invention relates to stapling and, more particularly, to improved staples for use in surgery and in other fields.
• Staples have a variety of uses. For example, surgeons use thin wire staples to join the cut ends of hollow organs or ducts (anastomosis) and to achieve hemostasis. Thin wire staples are made by deforming a length of thin wire with uniform cross section and material properties to a U-shape.
• FIG. 1 shows a common prior art thin wire staple 100, including a crown 101 and two legs 102. The staple shown in FIG. 1 has uniform cross section and material properties, except as these may be altered in the region where the staple legs join the crown during deformation of the wire to the U- shape.
• Surgical staples are made of materials inert to attack by body fluids, e.g.; stainless steels.
• FIG. 2 shows the staple of FIG. 1 deformed to a B-shape during installation due to its legs having been forced against an anvil with channels to direct the legs as they bend and deform.
• This anvil is located on the side of the material being stapled that is
• FIG. 2 shows that the separation of different locations on the legs 102 from the crown 101 varies for a B-shaped staple.
• the tissue compressed least by the staples must still be compressed sufficiently for the hemostasis despite the possibility that the tissue compressed most may be perforated or damaged due to excessive compression br distortion. Shrinkage of scar tissue over time can lead to adverse results, and thus it is important to avoid forming more scar tissue than necessary.
• Deformation zones may be formed by reducing the minimum moment of inertia, I, of the staple cross section in the deformation zones, or by reducing the modulus or elasticity, E, of the staple material.
• the staple has two legs, and each leg has a deformation zone in a predetermined region that is separated from the staple crown by a leg region with greater resistance to deformation than that of the deformation zone under the stress generated when the staple encounters an anvil during installation, so that the staple preferentially deforms in the deformation zone.
• the inventive staple is, preferably, deformed to a rectangular shape with rounded corners. This helps to achieve uniform compression and to minimize distortion of the stapled material.
• FIG. 1 depicts a prior art staple before installation
• FIG. 2 shows the prior art staple of FIG. 1 after being deformed to a B-shape
• FIG. 3 depicts an exemplary embodiment of the inventive staple
• FIG. 4 shows the staple of FIG. 3 after being deformed to a rectangular shape
• FIG. 5 shows exemplary cross sectional views (not to the scale of FIG. 3) of possible deformation zone and adjacent leg regions for the staple of FIG. 3;
• FIG. 6 shows a double staggered staple line
• FIG. 7 is a partial front view in section of a first type of exemplary anvil
• FIG. 8 is a partial front view in section of a second type of exemplary anvil
• FIG. 9 is an alternative embodiment of the invention for use on material with varying thickness
• FIG. 10 depicts a loaded strip (cartridge) of staples for use with the invention
• FIG. 11 shows an alternative embodiment of the present invention wherein the deformation zones are formed simultaneously with the installation of the staples
• FIG. 12 shows the embodiment of FIG. 11 in use
• FIG. 13 shows a cross sectional view of the inventive staple fully deformed and installed into tissue
• FIG. 14 shows an alternative embodiment of the inventive staple prior to deformation and installation
• FIG. 15 shows a cross sectional view of a prior art staple fully deformed to a B-shape and installed into tissue
• FIG. 16 shows a technique of forming deformation zones
• FIG. 17 shows a view of a notch formed on the outside of a staple leg.
• a deformation zone is created by weakening the staple in a predetermined region so that deformation preferentially occurs in that region during staple installation.
• the resistance to deformation of a region of a staple under stress is dependant on the magnitudes of its modulus of elasticity, E, in the region and the moment of inertia, I, in the region. Reducing one or both of these quantities in a region reduces the stress needed to deform a staple in that region. It is usually easier to reduce I than E.
• Deformation zones should not be formed by weakening the staple in the predetermined regions in such a manner as to result in staple failure, i.e., breakage, during staple deformation.
• the legs of the inventive staple should be matched to the requirements of the material stapled. That is, the locations of the deformation zones should be matched to the thickness of the material being stapled and to the compression desired, and the staple leg lengths should be sized to bring the legs into close proximity to achieve uniform compression of the stapled material and to prevent a bulge of material from between the tips of the legs. While such matching may require the availability of multiple staples, this is justifiable when the compression achieved and its uniformity are important.
• FIG. 3 shows an exemplary staple 300 in accordance with the present invention.
• the staple 300 includes a crown 301 and two legs 302.
• Each leg 302 has a deformation zone 305 with weakened resistance to bending into direction 304 as compared to the resistance of leg regions 306 and 307 which lie outside of the deformation zone 305.
• the staple 300 is subjected to stresses arising from forces acting in the direction 304, the legs will bend into that direction, and bending and deformation will take place preferentially in deformation zone 305.
• FIG. 4 the staple of FIG. 3 is shown deformed into a rectangular shape. Material stapled with the staple of FIG. 3 will be under more uniform compression than is the case with the B- shaped staple of FIG. 2.
• FIG. 4 reveals that the location and length of deformation zone 305 and the length of the staple leg 302 are important leg parameters in obtaining a desired compression for stapled material of a particular thickness and in bringing the staple leg ends into close proximity. Ideally, the tips of the staple legs should just about touch one another.
• the length of leg region 306 between the crown 301 and the deformation zone 305 should be matched to the requirements set by the combination of the thickness of the material being stapled and the compression of this material that is desired.
• the length of leg region 307 between the deformation zone 305 and the leg end 308 should be selected such that the separation of the leg ends 308 of the deformed staple is minimized without interference between the leg ends 308 occurring as the staple is deformed during installation.
• FIG. 2 A comparison of FIG. 2 and FIG. 4 reveals that material stapled with the staple 300 of FIG. 3 will be less distorted and under more uniform compression than occurs with B-shaped staples.
• FIG. 5 exemplary cross sections (not shown to the scale of FIG. 3) are shown for the legs 302 of the staple 300 of FIG. 3.
• FIG. 5(a) a cross section for regions of the staple legs 302 outside the deformation zone 305 is shown.
• FIG. 5(b) and (c) two different possible cross sections for the staple leg cross section in the deformation zone 305 are shown.
• the values of I for the staple leg in deformation zones with the cross sections shown in FIG. 5(b) or (c) for bending into direction 304 are less than if they had the cross section of FIG. 5(a) .
• FIG. 6 a double staggered staple line 600 formed from inventive staples 300 of FIG. 4 is shown, each row being offset with respect to the other row.
• Surgeons make use of double staggered staple lines, e.g., to compress tissue for hemostasis at the cut end of an organ or to perform an anastomosis.
• the present staples thus have application in hemostasis and anastomosis, for example.
• FIG. 7 a cross section is shown of an anvil 700 for use with the staple of FIG. 3 to produce the deformed staple of FIG. 4.
• Channels 701 formed in the anvil 700 direct bending and deformation of staple legs 302 when staple 300 is forced against anvil 700 and the legs 302 encounter the anvil 700.
• Anvil 700 is stationary as the staple 300 is forced against it.
• an anvil 800 alternative to that of FIG. 7 for use with the staple 300 of FIG. 3 is shown.
• the legs 302 of the staple 300 encounter channels 801 of anvil 800 after penetrating through the material being stapled (not shown in FIG. 8) .
• Anvil 800 moves towards the staple 300 as the staple 300 is forced against the anvil 800. This motion of the anvil may be accomplished using means well known to the art. The motion of the anvil minimizes distortion of the material being stapled by the staple legs 302 as they bend and deform.
• the stapler may include a stop (702, 802) to prevent staple bending beyond the desired amount, although such a stop is not required for the installation of a staple.
• An exemplary stop (702, 802) is shown, but other techniques using means well known in the art can be employed to prevent the stapler jaws from closing too much so that staples are deformed beyond desired points.
• FIG. 9 an alternative staple jaws arrangement 900 is shown which includes two stapler jaws 901 and 902 (jaw 902 functions as an anvil) . This embodiment can -be used if the thickness of the material being stapled varies over the length of a line of staples that the surgeon wishes to insert.
• the upper jaw 901 is slanted with respect to the lower jaw 902, as shown.
• the separation of the stapler jaws 901 and 902 varies in correspondence with the variation in the thickness of the material (not shown in FIG. 9) being stapled.
• the individual staples used with the arrangement of FIG. 9 would have leg deformation zones located differently with respect to each other in order to accommodate the different thicknesses of the material being stapled. Specifically, it can be seen from FIG. 9 that the staple contacting channel 903 should have shorter leg lengths between its leg deformation zones and the staple crown than should the staple contacting channel 904. Additionally, the leg lengths of the staple used at channel 903 may be less than the leg lengths of the staple used at channel 904.
• the staples prefferably be manufactured with uniform cross section and material properties, and for the deformation zones to be formed by the surgeon by modifying the staples just prior to use so that they correspond to the requirements of the material being stapled. For example, the surgeon could notch or file the staple legs to create the deformation zones, and/or cut the staple legs to desired lengths. Devices which can be used for such purposes can use means well .known in the art. Such an approach would reduce the size of staple inventory requirements.
• FIG. 10 shows a loading strip 1001 carrying prior art staples 100.
• the loading strip 1001 can be place into a device (not shown in FIG. 10) which forms deformation zones where they are desired, and which also cuts the staple legs 102 to the desired lengths. Devices which can be used for such purposes can utilize means well known in the art.
• the loading strip 1001 would be inserted into a suitable stapler (not shown in FIG. 10) prior to insertion of the staples 100.
• FIG. 11 shows a still further embodiment of the invention wherein deformation zones are created as staples are inserted rather than prior to the use of the staples.
• the arrangement of FIG. 11 shows stapler jaws 1102, 1103 with a staple 1110 located therebetween. (Stapler jaw 1103 functions as an anvil.)
• Two bars 1101 are employed to form the deformation zones.
• the bars may be attached to the lower jaw 1103 or the upper jaw 1102.
• the specific technique of attaching the bars is not shown in FIG. 1 for purposes of clarity and is not material to the operation of the present invention, however means well known to the art can be used for such purpose.
• the staple 1100 When the jaws 1102 and 1103 are brought towards each other, the staple 1100 will encounter the bars and bend and deform around the bars 1101. As seen in FIG. 12, the staple legs 1111 will deform so that leg portions 1106 and 1107 are at angles (preferably, at right angles) to each other, just as in embodiments where deformations zones are formed prior to staple insertion.
• the anvil moves after the staple legs pass partly or completely through the material being stapled ' .
• the bars may move aside so that the stapler can be easily removed, or the stapler may be set up so that the stapler can slide in a direction out of the plane of FIG. 12 to disengage from the staple.
• Means to accomplish such disengagement are not shown, but means well known to the art can be used for such purpose.
• FIG. 13 shows a side view in cross section of another embodiment, including staple 10 as installed into tissue 12.
• the legs 26 of the staple 10 each include an upper deformation zone 18 surrounded by a first section 16 and a second section 20, and a lower deformation zone 24 surrounded by a third section 22 and the second section 20.
• the staple 10 includes a crown 14.
• the tips 23 of the legs 26 penetrate through the tissue 12 being stapled and encounter the stapler anvil (not shown) , which causes third sections 22 to rotate inwardly as the legs 26 bend and deform at the lower deformation zones 24.
• the legs 26 also bend inwardly and deform at the upper deformation regions 18, so that second sections 20 rotate with respect to first sections 16 and assume angles with respect to the first sections, e.g., substantially right angles.
• the legs 26 bend initially at the lower deformation zones 24, and the lower deformation zones have more of a tendency to bend than the upper ones.
• third sections 22 penetrate into the tissue 12, as shown in FIG. 13.
• the amount of penetration into the tissue 12 depends upon the location of the lower deformation zones 24 with respect to the tips 23 of the legs 26.
• the upper deformation zones should be located such that the lower deformation zones 24 nearly touch after full deformation. This will prevent tissue from bulging out between staple legs 26.
• each staple is uniformly compressed.
• the entire stapled area can be viewed as having been divided into a plurality of areas, each of which is uniformly compressed.
• FIG. 14 shows the inventive staple 10 prior to installation into tissue 12.
• Staple 10 is a U-shaped before deformation, and includes an upper deformation zone 18 and a lower deformation zone 24 on each leg 26.
• Deformation zones 18 and 24 can be formed by reducing the sections of the legs 26 of the staple 10 or by other techniques, described herein.
• the third sections 22 can be used to effect a small penetrations of tissue 12, i.e., produce a small and controlled amount of tissue damage so as to thereby stimulate formation of a small amount of scar tissue (not shown)
• the second section 20 and first sections 16 can be used to achieve uniform compression of tissue 12.
• FIG. 15 shows a prior art B-shaped staple 28 installed into tissue 38.
• tissue 38 There is a region 36 under the ends 34 of the legs 32 void of tissue, and scar tissue must form in this void region if it is to be filled.
• the separation of the legs 32 from the crown 30 of the staple 28 is not uniform over the length of the legs, so that compression of the tissue 38 by the legs is not uniform. For such reasons, it is sometimes difficult to achieve hemostasis and allow proper nutrition of stapled tissues when using B-shaped staples.
• FIG. 16 shows two such notches, one notch on each leg 26 used to form the upper deformation zones 18.
• Lower deformation zones may or may not be used and, if used, are not shown for purposes of clarity, but this discussion is applicable to lower deformation zones also.
• Notches cannot be excessively “sharp” or else the staple will fail, i.e., break or fracture, when the leg sections 16 and 20 are rotated with respect to each other or subsequently.
• the radius at the juncture where the sides of the notch meet must not be so small that the material of which the staple is formed, e. g., a metal such as a stainless steel or titanium, breaks, cracks or fractures during deformation of the leg at the deformation zone in question. It has been found that notches result in a so-called stress concentration, i.e., a localized stress which is considerably greater than the average stress in the section. While localized yielding for ductile staple materials can minimize the effects of stress concentration, staples in surgery are in a critical application where staple failure cannot be tolerated because the danger to the health and well-being of the patient.
• stress concentration i.e., a localized stress which is considerably greater than the average stress in the section.
• Such a minimum radius (fillet) should be at least 3/1000 of an inch. It is also preferable to manufacture staples with notches having a fillet of at least 3/1000 of an inch on the inside of the leg, rather than a sharp notch.
• FIG. 17 shows an expanded view of an upper deformation zone 18 in leg 26 in the form of a notch with a fillet 40 located at the juncture of the sides 42 of the notch.
• R is the radius of the fillet, and R is equal to or greater than 3/1000 of an inch in order to minimize the possibility of breakage or fracture of the staple leg upon bending during staple installation and to provide acceptable reliability, i.e., to avoid subsequent breakage of the leg after installation.
• the staples may be used in applications other than surgery. Staples with more than two legs may be used, e.g., a leg located between two outer legs may be used, where this additional leg need not have any deformation zones.

Landscapes

• Health & Medical Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Surgery (AREA)
• Heart & Thoracic Surgery (AREA)
• Engineering & Computer Science (AREA)
• Biomedical Technology (AREA)
• Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
• Medical Informatics (AREA)
• Molecular Biology (AREA)
• Animal Behavior & Ethology (AREA)
• General Health & Medical Sciences (AREA)
• Public Health (AREA)
• Veterinary Medicine (AREA)
• Surgical Instruments (AREA)
• Materials For Medical Uses (AREA)

Applications Claiming Priority (5)

Publications (2)

Family

ID=26698528

Family Applications (1)

Country Status (6)

Families Citing this family (504)

Citations (4)

Family Cites Families (5)

• 1994
  • 1994-03-01 BR BR9405840-7A patent/BR9405840A/pt not_active Application Discontinuation
  • 1994-03-01 AU AU63568/94A patent/AU704533B2/en not_active Ceased
  • 1994-03-01 WO PCT/US1994/002227 patent/WO1994020030A1/en not_active Application Discontinuation
  • 1994-03-01 JP JP6520120A patent/JP2672713B2/ja not_active Expired - Fee Related
  • 1994-03-01 EP EP94910801A patent/EP0689400A4/en not_active Withdrawn
  • 1994-03-01 CA CA 2155750 patent/CA2155750C/en not_active Expired - Fee Related

Patent Citations (4)

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events