Negative pressure wound closure device

Abstract

The present invention relates to a negative pressure wound closure system and methods for using such a system. Preferred embodiments of the invention facilitate closure of the wound by preferentially contracting to provide for movement of the tissue. Preferred embodiments can utilize tissue grasping elements to apply a wound closing force to the tissue.

What is claimed is: 
     
         1 . A negative pressure wound therapy device, comprising:
 a porous foam material that is sized and shaped for positioning relative to a wound having wound margins wherein the porous foam material has a length, width, and height with a pore size and a pore density such that fluid is drained from the wound through the porous foam material upon application of negative pressure, the porous foam material being structured to preferentially contract along at least a first x-direction relative to a second y-direction upon application of a negative pressure to the wound to apply a closure force to the wound margins along the first x-direction.   
     
     
         2 . The negative pressure wound therapy device of  claim 1 , further comprising a negative pressure source that is coupled to the porous foam material with a tube to apply the closure force to the wound. 
     
     
         3 . The negative pressure wound therapy device of  claim 1 , wherein the porous foam material has vertical elements that inhibit contraction in a z-direction extending along the height. 
     
     
         4 . The negative pressure wound therapy device of  claim 1 , further comprising a film that is provided over a surface of the porous foam material. 
     
     
         5 . The negative pressure wound therapy device of  claim 4 , wherein the film comprises a mesh material extending along the surface of the porous foam material. 
     
     
         6 . The negative pressure wound therapy device of  claim 1 , wherein the porous foam material further comprises a plurality of spaced elements wherein the elements contract towards a longitudinal axis extending in a length direction to enable contraction in at least the first x-direction and inhibit collapse in at least the second y-direction. 
     
     
         7 . The negative pressure wound therapy device of  claim 6 , wherein the spaced elements comprise one or more regions of rigid material and regions of compressible material. 
     
     
         8 . The negative pressure wound therapy device of  claim 6 , wherein the spaced elements inhibit collapse in a height dimension. 
     
     
         9 . The negative pressure wound therapy device of  claim 6 , wherein the spaced elements comprise a stabilizing structure that compresses the porous foam material in at least the first x-direction to effect reapproximation of the wound. 
     
     
         10 . The negative pressure wound therapy device of  claim 6  wherein the spaced elements comprise a plurality of connected articulating elements. 
     
     
         11 . The negative pressure wound therapy device of  claim 6  wherein the porous foam material has an oval shape or rectangular shape. 
     
     
         12 . The negative pressure wound therapy device of  claim 1  wherein the porous foam material manages fluid within the wound such that the porous foam material slides over an underlying tissue during contraction. 
     
     
         13 . The negative pressure wound therapy device of  claim 1  wherein the porous foam material has regions of rigid material and regions of compressible material and wherein the porous foam material has different regions with variable pore sizes and/or pore densities. 
     
     
         14 . The negative pressure wound therapy device of  claim 1  wherein the porous foam material comprises a molded material. 
     
     
         15 . The negative pressure wound therapy device of  claim 1  wherein the porous foam material comprises a polyurethane. 
     
     
         16 . The negative pressure wound therapy device of  claim 1  wherein the porous foam material is positioned relative to a line of incision of the wound in a region of a dermis layer of a patient, the wound being sealed with a drape. 
     
     
         17 . The negative pressure wound therapy device of  claim 1  further comprising a negative pressure source coupled to the porous foam material with a tube to apply a negative pressure of 125 mm to 250 mm through a port to the porous foam material. 
     
     
         18 . The negative pressure wound therapy device of  claim 1  wherein the porous foam material comprises predetermined lines to change a shape of the porous foam material. 
     
     
         19 . The negative pressure wound therapy device of  claim 1  wherein the porous foam material has cleavage lines to alter at least one of a size and shape of the porous foam material. 
     
     
         20 . The negative pressure wound therapy device of  claim 1  wherein the porous foam material comprises an outer wall surface that contracts in size from an initial size to a reduced size upon application of negative pressure. 
     
     
         21 . A negative pressure wound therapy device comprising:
 a porous foam material that is sized and shaped for positioning relative to a wound wherein the porous foam material has a length, width, and height with a pore size and a pore density such that fluid is drained from the wound through the porous foam material upon application of negative pressure, the porous foam material being structured to preferentially contract along at least a first x-direction relative to a second y-direction upon application of a negative pressure to the wound to apply a closure force to wound edges of the wound along the first x-direction; and   a port to couple a negative pressure source to the porous foam material through a wound drape.   
     
     
         22 . The negative pressure wound therapy device of  claim 21 , further comprising a negative pressure source that is coupled to the porous foam material with a tube to apply the closure force to the wound. 
     
     
         23 . The negative pressure wound therapy device of  claim 21 , wherein the porous foam material has vertical elements that inhibit contraction in a z-direction extending along the height direction. 
     
     
         24 . The negative pressure wound therapy device of  claim 21 , further comprising a film that is provided over a surface of the wound filler material. 
     
     
         25 . The negative pressure wound therapy device of  claim 24 , wherein the film comprises a mesh material extending around the surface of the porous foam material. 
     
     
         26 . The negative pressure wound therapy device of  claim 21 , wherein the porous foam material further comprises a plurality of spaced elements wherein the spaced elements contract towards a longitudinal axis to enable contraction in at least the first x-direction and inhibit collapse in at least the second y-direction. 
     
     
         27 . The negative pressure wound therapy device of  claim 26 , wherein the spaced elements comprise one or more regions of rigid material surrounded by regions of compressible material. 
     
     
         28 . The negative pressure wound therapy device of  claim 26 , wherein the spaced elements inhibit collapse in a height dimension. 
     
     
         29 . The negative pressure wound therapy device of  claim 26 , wherein the spaced elements comprise a stabilizing structure that compresses the porous foam material in at least the first x-direction to effect reapproximation of the wound. 
     
     
         30 . The negative pressure wound therapy device of  claim 26  wherein the spaced elements comprise a plurality of connected articulating elements. 
     
     
         31 . The negative pressure wound therapy device of  claim 21  wherein the porous foam material has an oval shape or a rectangular shape. 
     
     
         32 . The negative pressure wound therapy device of  claim 21  wherein the porous foam material manages fluid within the wound such that the porous foam material slides over an underlying layer during contraction. 
     
     
         33 . The negative pressure wound therapy device of  claim 21  wherein the porous foam material has regions of rigid material and regions of compressible material and wherein the porous foam material has different regions with variable pore sizes and/or pore density. 
     
     
         34 . The negative pressure wound therapy device of  claim 21  wherein the porous foam material comprises a molded material. 
     
     
         35 . The negative pressure wound therapy device of  claim 21  further comprising a porous interface layer of material configured to lie between the porous foam material and an underlying tissue. 
     
     
         36 . The negative pressure wound therapy device of  claim 21  wherein at least one of the pore size or pore density is varied to control a vacuum force distribution within the porous foam material. 
     
     
         37 . The negative pressure wound therapy device of  claim 21  wherein the device is configured to attach to a dermis layer of the patient to apply the closure force to the dermis layer. 
     
     
         38 . A method for treating a wound with negative pressure comprising:
 connecting a source of negative pressure to a porous foam material having a pore size and a pore density such that a tube couples the source of negative pressure to a port in a sealing drape; the porous foam material having an interface layer on a bottom surface of the porous foam material, the interface layer having pores to pass fluid through the interface layer;   applying negative pressure to a wound with the porous foam material that is sized and shaped with a length, width and height to apply a closure force to opposing wound edges of a linear incision through a portion of skin of a patient; and   collapsing the porous foam material in a width direction in response to the application of negative pressure to the porous foam material.   
     
     
         39 . The method of  claim 38  wherein the step of applying negative pressure with the porous foam material further comprises positioning the porous foam material over tissue wherein a layer of the porous foam material extends between the tissue and the porous foam material. 
     
     
         40 . The method of  claim 38  wherein the porous foam material has an oval shape or a rectangular shape. 
     
     
         41 . The method of  claim 38  wherein the porous foam material comprises an open cell polyurethane foam. 
     
     
         42 . The method of  claim 38  wherein the porous foam material further comprises a plurality of stabilizer elements. 
     
     
         43 . The method of  claim 38  further comprising sensing a fluid pressure within the sealing drape. 
     
     
         44 . The method of  claim 43  further comprising controlling the applied negative pressure in response to the sensed fluid pressure. 
     
     
         45 . The method of  claim 38  further comprising measuring the closure force applied to the wound edges and controlling the negative pressure source to adjust the applied closure force.