APPARATUS AND METHOD FOR WOUND TREATMENT EMPLOYING PERIODIC SUB-ATMOSPHERIC PRESSURE

• US 20080208147A1
• Filed: 01/10/2007
• Published: 08/28/2008
• Est. Priority Date: 01/10/2007
• Status: Active Grant

• Current Assignee: Wake Forest University Health Sciences
• Original Assignee: Wake Forest University Health Sciences
• Inventors: Morykwas, Michael J., Webb, Lawrence X., Argenta, Louis O.
• Granted Patent: US 8,377,016 B2
• Time in Patent Office: Days
• US Class Current: 604/290
• CPC Class Codes: A61H 7/001 without substantial movement between the skin and the device
• CPC Class Codes: A61M 1/75 Intermittent or pulsating suction A61M1/63, A61M1/772 take precedence
• CPC Class Codes: A61M 1/915 Constructional details of the pressure distribution manifold
• CPC Class Codes: A61M 1/96 Suction control thereof

Abstract

A tissue treatment apparatus and method are provided for treating tissue by the application of the time-varying sub-atmospheric pressure. The apparatus includes a cover adapted to cover a wound and adapted to maintain sub-atmospheric pressure the site of the wound. The apparatus further includes a source of suction configured to generate a time-varying sub-atmospheric pressure having a periodic waveform comprising a gradual change in pressure. The suction source cooperates with the cover to supply the time-varying sub-atmospheric pressure under the cover to the wound. The time-varying sub-atmospheric pressure may vary between a first pressure value below the inherent tissue tension of the wound tissue and a second pressure value above the inherent tissue tension of the wound tissue.

Claims

1. An apparatus for administering sub-atmospheric pressure to a wound, comprising:

(a) a cover adapted to cover a wound and adapted to maintain sub-atmospheric pressure at the site of the wound;

(b) a seal configured to seal the cover to tissue surrounding the wound; and

(c) a source of suction configured to generate a time-varying sub-atmospheric pressure having a periodic waveform comprising a gradual change in pressure, the suction source cooperating with the cover to supply the time-varying sub-atmospheric pressure under the cover to the wound.

2. The apparatus of claim 1, wherein the gradual change in pressure extends over at least a portion of the period of the periodic waveform.

3. The apparatus of claim 1, wherein the pressure changes gradually over the full period of the periodic waveform.

4. The apparatus of claim 1, wherein time-varying sub-atmospheric pressure has a minimum value of 25 mm Hg below atmospheric pressure and a maximum value of 100 mm Hg below atmospheric pressure.

5. The apparatus of claim 1, wherein the time-varying sub-atmospheric pressure varies between a first pressure value below the inherent tissue tension of the wound tissue and a second pressure value above the inherent tissue tension of the wound tissue.

6. The apparatus of claim 1, wherein the source of suction is configured to generate a sinusoidal-waveform variation in pressure between a first pressure value below atmospheric pressure and a second pressure value below atmospheric pressure.

7. The apparatus of claim 6, wherein the first pressure value is 25 mm Hg below atmospheric pressure and the second pressure value is 100 mm Hg below atmospheric pressure.

8. The apparatus of claim 6, wherein the first pressure value is below the inherent tissue tension of the wound tissue and the second pressure value is above the inherent tissue tension of the wound tissue.

9. The apparatus of claim 1, wherein the source of suction is configured to generate a triangular-waveform variation in pressure between a first pressure value below atmospheric pressure and a second pressure value below atmospheric pressure.

10. The apparatus of claim 9, wherein the first pressure value is 25 mm Hg below atmospheric pressure and the second pressure value is 100 mm Hg below atmospheric pressure.

11. The apparatus of claim 9, wherein the first pressure value is below the inherent tissue tension of the wound tissue and the second pressure value is above the inherent tissue tension of the wound tissue.

12. The apparatus of claim 1, wherein the source of suction is configured to generate a sawtooth-waveform variation in pressure between a first pressure value below atmospheric pressure and a second pressure value below atmospheric pressure.

13. The apparatus of claim 12, wherein the first pressure value is 25 mm Hg below atmospheric pressure and the second pressure value is 100 mm Hg below atmospheric pressure.

14. The apparatus of claim 12, wherein the first pressure value is below the inherent tissue tension of the wound tissue and the second pressure value is above the inherent tissue tension of the wound tissue.

15. The apparatus of claim 1, wherein the source of suction comprises a vacuum pump.

16. The apparatus of claim 1, wherein the cover comprises a flexible sheet.

17. The apparatus of claim 16, wherein the seal includes an adhesive on a sheet surface facing the wound to attach and seal the sheet to tissue surrounding the wound.

18. The apparatus of claim 16, comprising a screen for placement at the wound between the cover and the wound.

19. The apparatus of claim 1, comprising a screen for placement at the wound between the cover and the wound.

20. The apparatus of claim 19, wherein the screen comprises open-cell foam.

21. The apparatus of claim 19, wherein the screen comprises a synthetic polymer material.

22. The apparatus of claim 19, wherein the screen comprises a non-adherent material.

23. The apparatus of claim 19, wherein the screen comprises a polymer mesh.

24. The apparatus of claim 23, wherein the screen comprises a synthetic polymer material.

25. The apparatus of claim 24, wherein the screen comprises an ointment.

26. The apparatus of claim 19, wherein the screen is configured to promote the formation of tissue of the type with which the screen is in contact.

27. The apparatus of claim 19, wherein the screen is configured to promote the formation of granulation tissue.

28. The apparatus of claim 19, wherein the screen is configured to promote tissue growth therein.

29. The apparatus of claim 19, wherein the screen is configured to deter tissue growth therein.

30. The apparatus of claim 19, wherein the screen comprises a bio-absorbable material.

31. The apparatus of claim 1, comprising a port at the cover configured to deliver the sub-atmospheric pressure under the cover.

32. The apparatus of claim 31, wherein port comprises a tube in gaseous communication with the source of suction.

33. The apparatus of claim 32, wherein the tube extends under an edge of the cover.

34. An apparatus for administering sub-atmospheric pressure to a wound, comprising:

(a) a self-adhesive cover adapted to cover and form a seal about a wound to maintain sub-atmospheric pressure at the site of the wound;

(b) port at the cover configured to deliver the sub-atmospheric pressure under the cover; and

(c) a source of suction for gaseous communication with the port, the source of suction configured to generate a sinusoidally varying sub-atmospheric pressure under the cover to the wound.

35. The apparatus of claim 34, wherein sinusoidally varying sub-atmospheric pressure has a minimum value of 25 mm Hg below atmospheric pressure and a maximum value of 100 mm Hg below atmospheric pressure.

36. The apparatus of claim 34, wherein the sub-atmospheric pressure varies between a first pressure value below the inherent tissue tension of the wound tissue and a second pressure value above the inherent tissue tension of the wound tissue.

37. The apparatus of claim 34, wherein the source of suction comprises a vacuum pump.

38. The apparatus of claim 34, wherein the cover comprises a flexible sheet.

39. The apparatus of claim 38, comprising a screen for placement at the wound between the cover and the wound.

40. The apparatus of claim 34, comprising a screen for placement at the wound between the cover and the wound.

41. The apparatus of claim 40, wherein the screen comprises open-cell foam.

42. The apparatus of claim 40, wherein the screen comprises a synthetic polymer material.

43. The apparatus of claim 40, wherein the screen comprises a non-adherent material.

44. The apparatus of claim 40, wherein the screen comprises a polymer mesh.

45. The apparatus of claim 44, wherein the screen comprises a synthetic polymer material.

46. The apparatus of claim 45, wherein the screen comprises an ointment.

47. The apparatus of claim 40, wherein the screen is configured to promote the formation of tissue of the type with which the screen is in contact.

48. The apparatus of claim 40, wherein the screen is configured to promote the formation of granulation tissue.

49. The apparatus of claim 40, wherein the screen is configured to promote tissue growth therein.

50. The apparatus of claim 40, wherein the screen is configured to deter tissue growth therein.

51. The apparatus of claim 40, wherein the screen comprises a bio-absorbable material.

52. The apparatus of claim 34, wherein the port comprises a tube in gaseous communication with the source of suction.

53. The apparatus of claim 52, wherein the tube extends under an edge of the cover.

54. An apparatus for administering sub-atmospheric pressure to a wound, comprising:

(a) a cover adapted to cover a wound to provide an enclosure above the wound in which sub-atmospheric pressure may be maintained;

(b) a screen configured to overlie the wound under the cover; and

(c) a vacuum means in gaseous communication with the cover to supply sub-atmospheric pressure within the enclosure, the vacuum means configured to generate a cyclically-varying sub-atmospheric pressure comprising a gradual change in pressure.

55. The apparatus of claim 54, wherein the gradual change in pressure extends over at least a portion of the cycle of the cyclically-varying sub-atmospheric pressure.

56. The apparatus of claim 54, wherein the pressure changes gradually over the full cycle of cyclically-varying the sub-atmospheric pressure.

57. The apparatus of claim 54, wherein the cyclically-varying sub-atmospheric pressure has a minimum value of 25 mm Hg below atmospheric pressure and a maximum value of 100 mm Hg below atmospheric pressure.

58. The apparatus of claim 54, wherein the cyclically-varying sub-atmospheric pressure varies between a first pressure value below the inherent tissue tension of the wound tissue and a second pressure value above the inherent tissue tension of the wound tissue.

59. The apparatus of claim 54, wherein the vacuum means is configured to generate a sinusoidal-waveform variation in pressure between a first pressure value below atmospheric pressure and a second pressure value below atmospheric pressure.

60. The apparatus of claim 59, wherein the first pressure value is 25 mm Hg below atmospheric pressure and the second pressure value is 100 mm Hg below atmospheric pressure.

61. The apparatus of claim 59, wherein the first pressure value is below the inherent tissue tension of the wound tissue and the second pressure value is above the inherent tissue tension of the wound tissue.

62. The apparatus of claim 54, wherein the vacuum means is configured to generate a triangular-waveform variation in pressure between a first pressure value below atmospheric pressure and a second pressure value below atmospheric pressure.

63. The apparatus of claim 62, wherein the first pressure value is 25 mm Hg below atmospheric pressure and the second pressure value is 100 mm Hg below atmospheric pressure.

64. The apparatus of claim 62, wherein the first pressure value is below the inherent tissue tension of the wound tissue and the second pressure value is above the inherent tissue tension of the wound tissue.

65. The apparatus of claim 54, wherein the vacuum means is configured to generate a sawtooth-waveform variation in pressure between a first pressure value below atmospheric pressure and a second pressure value below atmospheric pressure.

66. The apparatus of claim 65, wherein the first pressure value is 25 mm Hg below atmospheric pressure and the second pressure value is 100 mm Hg below atmospheric pressure.

67. The apparatus of claim 65, wherein the first pressure value is below the inherent tissue tension of the wound tissue and the second pressure value is above the inherent tissue tension of the wound tissue.

68. The apparatus of claim 54, wherein the vacuum means comprises a vacuum pump.

69. The apparatus of claim 54, wherein the cover comprises a flexible self-adhesive sheet for sealing to tissue about the wound.

70. The apparatus of claim 54, wherein the screen comprises open-cell foam.

71. The apparatus of claim 54, wherein the screen comprises a synthetic polymer material.

72. The apparatus of claim 54, wherein the screen comprises a non-adherent material.

73. The apparatus of claim 54, wherein the screen comprises a polymer mesh.

74. The apparatus of claim 73, wherein the screen comprises a synthetic polymer material.

75. The apparatus of claim 74, wherein the screen comprises an ointment.

76. The apparatus of claim 54, wherein the screen is configured to promote the formation of tissue of the type with which the screen is in contact.

77. The apparatus of claim 54, wherein the screen is configured to promote the formation of granulation tissue.

78. The apparatus of claim 54, wherein the screen is configured to promote tissue growth therein.

79. The apparatus of claim 54, wherein the screen is configured to deter tissue growth therein.

80. The apparatus of claim 54, wherein the screen comprises a bio-absorbable material.

81. The apparatus of claim 54, comprising a port at the cover configured to deliver the sub-atmospheric pressure under the cover.

82. The apparatus of claim 81, wherein the port comprises a tube in gaseous communication with the vacuum means.

83. The apparatus of claim 82, wherein the tube extends under an edge of the cover.

91. The apparatus of claim 54, wherein the vacuum means is configured to generate a sawtooth-waveform variation in pressure between a first pressure value below atmospheric pressure and a second pressure value below atmospheric pressure.

92. The apparatus of claim 91, wherein the first pressure value is 25 mm Hg below atmospheric pressure and the second pressure value is 100 mm Hg below atmospheric pressure.

84. An apparatus for administering sub-atmospheric pressure to a wound, comprising:

(a) a cover adapted to cover a wound to provide an enclosure above the wound in which sub-atmospheric pressure may be maintained;

(b) a port disposed at the cover configured to deliver the sub-atmospheric pressure under the cover; and

(c) a vacuum means in gaseous communication with the port to supply sub-atmospheric pressure within the enclosure, the vacuum means configured to generate a cyclically-varying sub-atmospheric pressure comprising a gradual change in pressure over at least a portion of the cycle, the change ranging from first pressure value below the inherent tissue tension of the wound tissue to a second pressure value above the inherent tissue tension of the wound tissue.

85. The apparatus of claim 84, wherein the pressure changes gradually over the full cycle of cyclically-varying the sub-atmospheric pressure.

86. The apparatus of claim 84, wherein the cyclically-varying sub-atmospheric pressure has a minimum value of 25 mm Hg below atmospheric pressure and a maximum value of 100 mm Hg below atmospheric pressure.

87. The apparatus of claim 84, wherein the vacuum means is configured to generate a sinusoidal-waveform variation in pressure between a first pressure value below atmospheric pressure and a second pressure value below atmospheric pressure.

88. The apparatus of claim 87, wherein the first pressure value is 25 mm Hg below atmospheric pressure and the second pressure value is 100 mm Hg below atmospheric pressure.

89. The apparatus of claim 84, wherein the vacuum means is configured to generate a triangular-waveform variation in pressure between a first pressure value below atmospheric pressure and a second pressure value below atmospheric pressure.

90. The apparatus of claim 89, wherein the first pressure value is 25 mm Hg below atmospheric pressure and the second pressure value is 100 mm Hg below atmospheric pressure.

93. The apparatus of claim 84, wherein the vacuum means comprises a vacuum pump.

94. The apparatus of claim 84, wherein the cover comprises a flexible self-adhesive sheet for sealing to tissue about the wound.

95. The apparatus of claim 94, comprising a screen for placement at the wound between the cover and the wound.

96. The apparatus of claim 84, comprising a screen for placement at the wound between the cover and the wound.

97. The apparatus of claim 96, wherein the screen comprises open-cell foam.

98. The apparatus of claim 96, wherein the screen comprises a synthetic polymer material.

99. The apparatus of claim 96, wherein the screen comprises a non-adherent material.

100. The apparatus of claim 96, wherein the screen comprises a polymer mesh.

101. The apparatus of claim 100, wherein the screen comprises a synthetic polymer material.

102. The apparatus of claim 101, wherein the screen comprises an ointment.

103. The apparatus of claim 96, wherein the screen is configured to promote the formation of tissue of the type with which the screen is in contact.

104. The apparatus of claim 96, wherein the screen is configured to promote the formation of granulation tissue.

105. The apparatus of claim 96, wherein the screen is configured to promote tissue growth therein.

106. The apparatus of claim 96, wherein the screen is configured to deter tissue growth therein.

107. The apparatus of claim 96, wherein the screen comprises a bio-absorbable material.

108. The apparatus of claim 84, wherein the port comprises a tube in gaseous communication with the vacuum means.

109. The apparatus of claim 108, wherein the tube extends under an edge of the cover.

110. The apparatus according to any one of claims 3, 5, 19-30, 56, 58, 70-80, 85, or 96-107, wherein the gradual change in pressure consists of a continuous change in pressure.

111. The apparatus according to any one of claims 3, 5, 19-30, 56, 58, 70-80, 85, or 96-107, wherein the gradual change in pressure comprises a digitized waveform.

112. A method for administering sub-atmospheric pressure to a wound, comprising the steps of:

(a) covering a wound with a wound cover configured to maintain sub-atmospheric pressure under the cover at the site of the wound;

(b) sealing the cover to tissue surrounding the wound to provide an enclosure for maintaining sub-atmospheric pressure under the cover about the wound; and

(c) applying time-varying sub-atmospheric pressure under the cover to the wound, the sub-atmospheric pressure having a periodic waveform comprising a gradual change in pressure.

113. The apparatus of claim 112, wherein the gradual change in pressure extends over at least a portion of the period of the periodic waveform.

114. The apparatus of claim 112, wherein the pressure changes gradually over the full period of the periodic waveform.

115. The method of claim 112, wherein the time-varying sub-atmospheric pressure has a minimum value of 25 mm Hg below atmospheric pressure and a maximum value of 100 mm Hg below atmospheric pressure.

116. The method of claim 112, wherein the time-varying sub-atmospheric pressure varies between a first pressure value below the inherent tissue tension of the wound tissue and a second pressure value above the inherent tissue tension of the wound tissue.

117. The method of claim 112, wherein the time-varying sub-atmospheric pressure comprises a sinusoidal-waveform variation in pressure that varies between a first pressure value below atmospheric pressure and a second pressure value below atmospheric pressure.

118. The method of claim 117, wherein the first pressure value is 25 mm Hg below atmospheric pressure and the second pressure value is 100 mm Hg below atmospheric pressure.

119. The method of claim 117, wherein the first pressure value is below the inherent tissue tension of the wound tissue and the second pressure value is above the inherent tissue tension of the wound tissue.

120. The method of claim 112, wherein the time-varying sub-atmospheric pressure comprises a triangular-waveform variation in pressure between a first pressure value below atmospheric pressure and a second pressure value below atmospheric pressure.

121. The method of claim 120, wherein the first pressure value is 25 mm Hg below atmospheric pressure and the second pressure value is 100 mm Hg below atmospheric pressure.

122. The method of claim 120, wherein the first pressure value is below the inherent tissue tension of the wound tissue and the second pressure value is above the inherent tissue tension of the wound tissue.

123. The method of claim 112, wherein the time-varying sub-atmospheric pressure comprises a sawtooth-waveform variation in pressure between a first pressure value below atmospheric pressure and a second pressure value below atmospheric pressure.

124. The method of claim 123, wherein the first pressure value is 25 mm Hg below atmospheric pressure and the second pressure value is 100 mm Hg below atmospheric pressure.

125. The method of claim 123, wherein the first pressure value is below the inherent tissue tension of the wound tissue and the second pressure value is above the inherent tissue tension of the wound tissue.

126. The method of claim 112, comprising placing a screen between the cover and the wound.

127. The method of claim 126, wherein the screen comprises open-cell foam.

128. The apparatus of claim 126, wherein the screen comprises a synthetic polymer material.

129. The method of claim 126, wherein the screen comprises a non-adherent material.

130. The apparatus of claim 126, wherein the screen comprises a polymer mesh.

131. The method of claim 130, wherein the screen comprises a synthetic polymer material.

132. The method of claim 131, wherein the screen comprises an ointment.

133. The method of claim 126, wherein the screen is configured to promote the formation of tissue of the type with which the screen is in contact.

134. The method of claim 126, wherein the screen is configured to promote the formation of granulation tissue.

135. The method of claim 126, wherein the screen is configured to promote tissue growth therein.

136. The apparatus of claim 126, wherein the screen is configured to deter tissue growth therein.

137. The method of claim 126, wherein the screen comprises a bio-absorbable material.