U.S. patent application number 10/442488 was filed with the patent office on 2004-09-09 for tissue harvesting device and method.
This patent application is currently assigned to KCI Licensing, Inc.. Invention is credited to Mishra, Ajit, Ohira, Makoto, Seegert, Charles.
Application Number | 20040175690 10/442488 |
Document ID | / |
Family ID | 33489322 |
Filed Date | 2004-09-09 |
United States Patent
Application |
20040175690 |
Kind Code |
A1 |
Mishra, Ajit ; et
al. |
September 9, 2004 |
Tissue harvesting device and method
Abstract
A tissue harvesting method and device for obtaining micrograft
tissue particles within the size range of 50-1500 microns, and more
preferably 500-1000 microns, and most preferably 600 microns. The
particles may be processed after a piece of donor tissue has been
excised from the donor site, or processed into the desired size
directly at the donor site, and thereafter excised. Cutters having
blades or cutting edges spaced in the range of 50-1500 microns are
utilized to obtain particles within the desired size range. An
elastomer is positioned between the cutting edges to push the
excised particles out of the blades for ease of use.
Inventors: |
Mishra, Ajit; (San Antonio,
TX) ; Seegert, Charles; (San Antonio, TX) ;
Ohira, Makoto; (Newton, MA) |
Correspondence
Address: |
Kinetic Concepts, Inc.
Legal Dept - Mfg.
P.O. Box 659508
San Antonio
TX
78265-9508
US
|
Assignee: |
KCI Licensing, Inc.
8023 Vantage Drive
San Antonio
TX
78230-4726
|
Family ID: |
33489322 |
Appl. No.: |
10/442488 |
Filed: |
May 21, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10442488 |
May 21, 2003 |
|
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10379342 |
Mar 3, 2003 |
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Current U.S.
Class: |
435/1.1 ;
435/379 |
Current CPC
Class: |
Y10T 83/768 20150401;
Y10T 83/7876 20150401; Y10T 83/0481 20150401; Y10T 83/465 20150401;
Y10T 407/19 20150115; A61B 2017/00969 20130101; A61B 2017/3225
20130101; Y10T 83/748 20150401; Y10T 83/0586 20150401; Y10T 408/34
20150115; Y10T 408/89 20150115; Y10T 83/0524 20150401; Y10T 83/0215
20150401; Y10T 83/483 20150401; Y10T 407/12 20150115; Y10T 83/9498
20150401; Y10T 83/4766 20150401; Y10T 83/4795 20150401; A61B 17/322
20130101; Y10T 83/0207 20150401; Y10T 83/7809 20150401; Y10T 83/788
20150401; Y10T 83/0515 20150401; Y10T 83/9372 20150401 |
Class at
Publication: |
435/001.1 ;
435/379 |
International
Class: |
A01N 001/02 |
Claims
What is claimed is:
1. A method of harvesting tissue for transplantation to a recipient
site, comprising the steps of: (i) extracting a section of dermal
tissue from a donor site; (ii) processing said tissue through a
tissue cutter such that said tissue is processed in to particles of
a size conducive for cell proliferation greater than about 6:1 and
up to about 20:1; and (iii) mechanically retrieving said processed
tissue from said cutter.
2. The method of claim 1 wherein said particles are within the size
range of about 50 microns to 1500 microns.
3. The method of claim 1 wherein said particles are within the size
range of about 500 microns to 1000 microns.
4. The method of claim 1 wherein said particles are within the size
of about 600 microns.
5. The method of claim 1 wherein said cutter is comprised of a
cylindrical roller having a raised surface of evenly spaced square
shaped blades.
6. The method of claim 5 wherein said cutter is further comprised
of a handle positioned axially along said cylindrical roller.
7. The method of claim 1 wherein said cutter is comprised of a die
having a first plurality of raised edges and a second plurality of
raised edges positioned perpendicular to said first plurality of
raised edges.
8. The method of claim 7 wherein said die is pressed on said
section of dermal tissue by means of an arbor.
9. The method of claim 7 wherein said die is manually pressed onto
said section of dermal tissue.
10. The method of claim 7 wherein said die is pressed onto said
section of dermal tissue from a proximal side of said tissue to a
distal side of said tissue by means of a reciprocating roller.
11. The method of claim 7 wherein said die is concave, such that
said raised edges are positioned on an outer curve of said concave
die.
12. The method of claim 1 wherein said cutter is comprised of a
first cylindrical roller positioned parallel to a second
cylindrical roller, and wherein said first cylindrical roller is
comprised of a first set of raised, parallel cutting edges, and
wherein said second cylindrical roller is comprised of a second set
of raised, parallel cutting edges, and wherein said first set of
raised cutting edges is positioned approximately perpendicular to
said second set of raised, parallel cutting edges.
13. The method of claim 12 wherein said first cylindrical roller
cuts along a top face of said dermal tissue, and said second
cylindrical roller cuts along a bottom face of said dermal
tissue.
14. The method of claim 12 wherein said first and second
cylindrical rollers cut along a single face of said dermal
tissue.
15. The method of claim 1 wherein said cutter is comprised of a
plurality of circular blades in parallel arrangement.
16. The method of claim 15 wherein said blades are adjustably
secured so as to create a space between said blades, such that said
space is within the range of about 50 microns to about 1500
microns.
17. The method of claim 15 wherein said blades are adjustably
secured so as to create a space between said blades, such that said
space is about 600 microns.
18. The method of claim 1 wherein said cutter is comprised of a
plurality of microtomes.
19. The method of claim 1 wherein said cutter is comprised of a
plurality of capillary tubes having a sharpened edge and arranged
in a bundle.
20. The method of claim 1 wherein said step of mechanically
retrieving said processed tissue from said cutter comprises
positioning an elastomer between cutting surfaces of said
cutter.
21. A method of harvesting tissue for transplantation to a
recipient site, comprising the steps of: (i) applying a plurality
of vertical cuts to a section of donor tissue at a donor site; and
(ii) extracting a plurality of donor particles from said donor site
by applying a horizontal cut along a connection point of said donor
particles to said donor site and through said vertical cuts, such
that said donor particles are of a size conducive for proliferation
greater than about 6:1 and up to about 20:1; and
22. The method of claim 21 wherein said extracting step is
comprised of passing a dermatome across said vertical cuts.
23. The method of claim 21 wherein said size of said donor
particles are within the range of about 50 microns to about 1500
microns.
24. The method of claim 21 wherein said size of said donor
particles is within the range of about 300 microns to about 800
microns.
25. The method of claim 21 wherein said size of said donor
particles is about 600 microns.
26. The method of claim 21 wherein said applying step is comprised
of pressing a die having a plurality of perpendicularly arranged
edges against said donor site.
27. The method of claim 26 wherein said extracting step is
comprised of oscillating said die along a vertical axis.
28. The method of claim 21 wherein said applying step is comprised
of pressing a rigid sheet having a plurality of opposing concave
cutting edges.
29. The method of claim 28 wherein said extracting step is
comprised of oscillating said rigid sheet along a vertical
axis.
30. A cutter for processing tissue into particles suitable for
transplantation, comprised of a cylindrical roller having a raised
surface of evenly spaced perpendicularly arranged cutting
edges.
31. The cutter of claim 30 wherein said space between said cutting
edges is between about 50 microns and about 1500 microns.
32. The cutter of claim 30 wherein said space between said cutting
edges is about 600 microns.
33. The cutter of claim 30 further comprising a piezo-electric
driver for oscillating cutter across the surface of tissue.
34. A cutter for processing tissue into particles suitable for
transplantation, comprised of a rigid sheet of raised cutting
edges.
35. The cutter of claim 34 wherein said raised cutting edges form a
grid having separations between said cutting edges between about 50
microns and about 1500 microns.
36. The cutter of claim 34 wherein said raised cutting edges form a
grid having separations between said cutting edges of about 600
microns.
37. The cutter of claim 34 wherein said sheet is concave and said
raised cutting edges project from an outer curve of said concave
sheet.
38. The cutter of claim 34 wherein said raised cutting edges are
comprised of a plurality of opposing concave cutting edges.
39. The cutter of claim 38 further comprising an oscillating driver
connected to said cutter for oscillating said cutter across the
surface of said tissue.
40. A cutter for processing tissue into particles suitable for
transplantation, comprising: (i) a first cylindrical roller, having
a first set of raised, parallel cutting edges; and (ii) a second
roller having a second set of raised, parallel cutting edges; and
(iii) wherein said first set of raised cutting edges is
approximately perpendicular to said second set of raised cutting
edges.
41. The cutter of claim 40 wherein said cutting edges are separated
by between about 50 microns and 1500 microns.
42. The cutter of claim 40 wherein said cutting edges are separated
by about 600 microns.
43. A cutter for processing tissue into particles suitable for
transplantation, comprising a plurality of circular blades in
parallel arrangement along a horizontal axis, and wherein said
blades are adjustably secured to create a uniform distance between
each circular blade.
44. The cutter of claim 43 further comprising a handle positioned
along said horizontal axis.
45. The cutter of claim 43 wherein said distance between each
circular blade is between about 50 microns and 1500 microns.
46. The cutter of claim 43 wherein said distance between each
circular blade is about 600 microns.
47. A cutter for processing tissue into particles suitable for
transplantation, comprising: (i) a housing; (ii) a cylindrical
press movable within said housing from a closed distal end of said
housing toward an open proximal end of said housing; (iii) an
elastomer fixedly connected to said press; (iv) a removable cap
positioned at said open proximal end of said housing; and (v) a
plurality of blades fixedly connected within said housing, and
interposed between said press and said open proximal end.
48. The cutter of claim 47 wherein said blades are separated by a
distance of between about 50 microns and 1500 microns.
49. The cutter of claim 47 wherein said blades are separated by a
distance of about 600 microns.
50. A cutter for processing tissue into particles suitable for
transplantation, comprising: (i) a plurality of serrated discs,
wherein said discs are slotted, and wherein said discs are fixedly
positioned along an axis such that a space is created between said
discs for receiving a tissue sample; (ii) a ring of longitudinal
blades configured to pass between said serrations of said serrated
discs.
51. The cutter of claim 50 further comprising a clamp for forcing
said tissue into said cutter.
Description
RELATED APPLICATIONS
[0001] This application is a continuation-in-part of co-pending
U.S. patent application Ser. No. 10/379,342, entitled "Tissue
Processing System," filed on Mar. 3, 2003.
FIELD OF THE INVENTION
[0002] The invention relates to a device and method for harvesting
dermal tissue. More particularly, this invention relates to a
device and method for extracting small particles of dermal tissue
for transplantation to a recipient site.
BACKGROUND OF THE INVENTION
[0003] Traditional skin grafting is accomplished by taking a thin
slice of dermal tissue from a donor site in order to cover a wound
site, such as a burn area. In some instances, the slice of dermal
tissue is meshed to expand its size, creating a meshed graft.
Traditional devices used to harvest the tissue from the donor site
include dermatomes for removing a thin slice of the upper layers of
skin from a donor site. The slice is then meshed using traditional
techniques to create and expand the sheet of skin tissue that gives
the slice a weave-like appearance. The purpose of expanding the
skin from the donor site is to increase the amount of area on a
recipient site that can be covered by the donor site. Some of the
most desirable expansion ratios currently available are 6:1. That
is, under the most ideal conditions, skin taken from a donor site
would be able to cover a recipient site that is six times larger
than the donor site.
[0004] Traditional meshed grafting techniques have been shown to
yield 90% viability at the donor site. A slightly lower viability
rate occurs for non-meshed sheet grafts, mostly due to fluid
accumulation under the sheet graft. Factors that lead to graft
failure include poor circulation, unclean wounds, patient
interference with the graft dressing, obesity, and smoking.
Additionally, in at least approximately 10% of cases, infection at
the donor site occurs. Although such donor site infections are not
likely related to graft failure at the wound site, they still pose
problems for both the patient and caregiver.
[0005] As mentioned, traditional meshing techniques yield a most
favorable expansion ratio of 6:1. For example, a 1 cm.sup.2 donor
site can cover a 6 cm.sup.2 wound site. While greater ratios of 9:1
and 12:1 may be possible using meshing techniques, there is also a
significant delay in epithelialization with such ratios.
[0006] Micro grafting techniques, in which the donor tissue is
actually minced in order to achieve a greater than 10:1 expansion
ratio, are known in the art. Such techniques allow for a much
greater coverage area from a small donor site. However, traditional
techniques are cumbersome, and often the viability of the cells is
compromised to such an extent that sometimes less than 50% of the
cells are viable when applied to the wound site. Additionally,
traditional techniques have thus far been inadequate in producing
viable cells in the range of 500-1500 microns.
[0007] Traditional micrograft techniques, dating back to 1963,
utilized minced skin that is between 1/8.sup.th inch (approximately
3 mm, or 3000 microns) or {fraction (1/16)}.sup.th inch
(approximately 1.5 mm, or 1500 microns) in size. However,
disadvantages of using pieces larger than 1500 microns have been
noted. Among the disadvantages are that many of the cells are
trapped within the pieces of skin, and are thus unable to
proliferate or produce new cells required to form new skin.
Furthermore, if such large pieces of skin are to be transplanted,
the epidermis side of each piece has to be oriented upwards, and
the dermis side oriented downwards. This makes the procedure
tedious and impractical. Also, the appearance of the new skin that
is produced using particles of this size is poor, often having a
cobblestone appearance.
[0008] Other micrografting techniques have utilized minced skin
that is 200 to 500 microns in size. While sometimes producing
cosmetically better grafts over the larger micrografts, many of the
cells contained in the particles are rendered non-viable by the
process of producing cells of such a small size.
[0009] It is therefore an object of this invention to provide a
system for obtaining and processing tissue samples from a donor
site on the order of 50-1500 microns in size, such that the vast
majority of tissue processed at this size is viable when
transplanted to a recipient site. It is a further object of the
present invention to strike the ideal balance between cell
viability and cell proliferation between the size range of 500-1500
microns, and most preferably 600 microns, which has heretofore not
been achieved.
[0010] Additional objects of the present invention include a
significant reduction in the size of the donor site as compared to
traditional mesh-graft procedures; minimizing scarring of the graft
site as compared to traditional mesh-graft procedures; improvement
of the pliability of tissue in the graft site; improvement of the
cosmetic appearance of the graft site as compared to current
methods; and improvement of graft "take."
SUMMARY OF THE INVENTION
[0011] In accordance with the foregoing objects, the present
invention generally comprises a device for harvesting tissue from a
donor site into particles in the size range of 50-1500 microns, and
most preferably about 600 microns, such that the particles may
produce an expansion ratio, or cell proliferation, of at least 6:1
and up to or over 20:1.
[0012] The present invention includes a method for cutting and
removing tissue from a donor site. The typical donor site may be
equivalent to a split-thickness-skin graft ("STSG"). A traditional
dermatome may be utilized to obtain the donor sample, or STSG,
which is then processed into smaller micrografts between 50-1500
microns in size. More preferably, the micrografts are processed
into sizes between 500 microns and 1500 microns, and most
preferably to about 600 microns, which has been shown to yield the
greatest viability and proliferation. A cutter is utilized to
process the tissue into the desired size. Alternatively, the donor
tissue may be processed into the desired size directly on the donor
site, and thereafter removed from the donor site.
[0013] The present invention also includes a cutter for processing
the tissue into the desired size range. Several alternative cutters
may be utilized in accordance with the present invention, including
roller cutters. In one embodiment, a roller have having a
square-shaped grid pattern of raised edges is used to achieve
tissue particles of the desired size. Alternatively, dual rollers
may be utilized, in which each roller has a series of evenly spaced
parallel raised cutting edges, which are oriented perpendicular to
the raised edges on the opposing roller. The donor tissue or STSG
may be passed between the rollers, or the rollers may be pressed
against a single surface of the donor tissue.
[0014] Other alternative cutters include die-cast rigid sheets,
which may be flat or concave. The rigid sheet is pressed to the
donor tissue manually or by means of a reciprocating roller. The
cutting edges of the rigid sheet include a raised, square-shaped
grid pattern, or alternatively, a series of opposing facing, raised
concave cutting edges.
[0015] Cutters that may be utilized to process the donor tissue
directly at the donor site include bundled capillary tubes, having
a sharpened edge. Other cutters for processing donor tissue that
has already been excised from the donor site include a cylindrical
press cutter.
[0016] Removing the tissue from the cutters, after it has been
processed into the desired size, is accomplished by positioning an
elastomer, such as rubber or other flexible material, between the
cutting surfaces of the cutters. As the cutter is pushed into the
donor tissue, the elastomer retreats from the cutting edge to allow
the tissue to be cut. As pressure is relieved from the cutter, the
elastomer returns to its original position, thereby pushing the cut
tissue out from the cutting edges.
[0017] The foregoing has outlined some of the more pertinent
objects of the present invention. These objects should be construed
to be merely illustrative of some of the more prominent features
and applications of the invention. Many other beneficial results
can be attained by applying the disclosed invention in a different
manner or by modifying the invention as will be described.
Accordingly, other objects and a fuller understanding of the
invention may be had by referring to the following Detailed
Description of the Invention, which includes the preferred
embodiment
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] These and other features and advantages of the invention
will now be described with reference to the drawings of certain
preferred embodiments, which are intended to illustrate and not to
limit the invention, and wherein like reference numbers refer to
like components, and in which:
[0019] FIG. 1 is a perspective view of a donor tissue excised from
a donor site using traditional methods;
[0020] FIG. 2 is a perspective view of a cylindrical roller cutter
of the present invention;
[0021] FIG. 3 is a perspective view of donor tissue processed into
the desired size directly at the donor site in accordance with the
present invention;
[0022] FIGS. 4A, 4B, and 4C are perspective views of a rigid sheet
cutter of the present invention;
[0023] FIG. 5 is a perspective view of a circular blade cutter of
the present invention;
[0024] FIGS. 6A and 6b are perspective views of dual roller cutters
of the present invention;
[0025] FIG. 7 is a perspective view of a stacked microtome cutter
of the present invention;
[0026] FIG. 8 is a perspective view of a bundled capillary tubes
cutter of the present invention;
[0027] FIG. 9 is a cross-sectional view of a cylindrical press
cutter of the present invention;
[0028] FIG. 10 is a perspective view of a stacked disc cutter of
the present invention; and
[0029] FIG. 11 is cross-sectional view of a tissue extraction means
of the present invention.
DESCRIPTION OF THE INVENTION
[0030] Although those of ordinary skill in the art will readily
recognize many alternative embodiments, especially in light of the
illustrations provided herein, this detailed description is
exemplary of the preferred embodiment of the present invention as
well as alternate embodiments, the scope of which is limited only
by the claims that may be drawn hereto.
[0031] Referring now to the drawings, the details of preferred
embodiments of the present invention are graphically and
schematically illustrated. Like elements in the drawings are
represented by like numbers, and any similar elements are
represented by like numbers with a different lower case letter
suffix.
[0032] As illustrated in FIG. 1, a donor tissue sample 10, such as
a split-thickness-skin graft ("STSG") may be removed from a healthy
region of skin tissue 12 using traditional techniques, such as by
running a dermatome 14 across the surface of the donor site 12. The
donor tissue 10 is positioned on a flat surface 18, so that the
cutter 16 of the present invention may be applied to it, as is
shown in FIG. 2, in order to process the tissue into the desired
size. In the preferred embodiment, the donor tissue 10 is processed
into the desired size range of between 50-1500 microns.sup.2, more
preferably between 500-1000 microns.sup.2, and most preferably 600
microns.sup.2. Alternatively, the donor tissue 10 may be processed
into the desired size or size range directly at the wound site 12,
as depicted in FIG. 3. A dermatome 14, or similar traditional
device, may be used to excise the processed tissue particles 10
from the donor site 12.
[0033] Returning now to FIG. 2, there is shown a cutter 16 of the
present invention for processing donor tissue 10 into particles 20
of the desired size. The cutter 16 consists of a cylindrical roller
22 in which the cutting surface 24 consists of a square-shaped grid
pattern of raised edges 26, that form blades for cutting the donor
tissue 10 into particles 20 of the desired size. The roller 22 is
pressed onto the donor tissue 10 manually, such as by handles 30
attached along the longitudinal axis 28 of the roller 22, or by an
electromechanical actuator (not shown), such as an electric motor
and axel along the longitudinal axis 28, similar to that used in
traditional dermatomes known in the art.
[0034] An alternative embodiment of the cutter 16, as illustrated
in FIGS. 4A, 4B, and 4C, includes a rigid sheet 34 having a
plurality of raised cutting edges 32. The rigid sheet 34 may be a
die as shown in FIGS. 4A and 4B, in which the cutting edges 32 form
a square-shaped grid pattern, in which each grid is the size of the
desired particle to be cut from the donor tissue 10. Alternatively,
the cutting edges 32 may consist of a series of oppositely facing,
raised concave cutters 36, as shown in FIG. 4C. The rigid sheet 34
may be flat, as shown in FIG. 4A, or concave to aid in manual
pressing of the cutter 16 to the donor tissue 10, as shown in FIG.
4B. In such an embodiment, the cutting edges are positioned on the
outer curve 38 of the rigid sheet 34.
[0035] The particles may be extracted from the donor tissue after
application of the rigid sheet 34 cutter 16 by oscillating the
sheet 34, such as by a piezo-electric driver, along a vertical axis
40, as illustrated in FIG. 4C. Alternatively, the rigid sheet 34
may be pressed onto the donor tissue 10 manually. Other alternative
pressing means include use of an arbor (not shown), such as an axle
press known in the art, or by means of a roller actuator 42, that
presses the sheet 34 against the donor tissue 10 as the roller 44
of the actuator 42 is passed across the surface of the rigid sheet
34, as shown in FIG. 4A.
[0036] Turning now to FIG. 5, there is illustrated a further
embodiment of the cutter 16. The cutter is comprised of a series of
sharpened circular blades 50 arranged in parallel to one another
and fixed along an axis 52. A handle 60 may be positioned along an
opposing axis 62. The distance 54 between the blades 50 may be
adjusted according to the desired size of the tissue sample to be
obtained. The preferred distance 54 between each blade 50 is in the
range of about 50 microns to 1500 microns. The more preferable
distance 54 is between about 500 microns and 1000 microns, and most
preferably 600 microns. In the preferred embodiment, the space 54
between blades 50 may be adjusted to within the preferred distances
mentioned, or alternatively, fixed to a distance within the
preferred distances mentioned. The distance 54 between the blades
50 allows for uniform tissue particles to be produced at the ideal
range of 50 square microns to 1500 square microns. As mentioned,
tissue particles within the desired range have been shown to yield
the highest expansion ratio while retaining the greatest
viability.
[0037] FIGS. 6A and 6B illustrate a further embodiment of the
cutter 16, which consists of a pair of cylindrical rollers 70a,
70b. The first cylindrical roller 70a has a first set of raised,
parallel cutting edges 72. The second cylindrical roller 70b has a
second set of raised, parallel cutting edges 74 that are oriented
approximately perpendicular to the first set of raised cutting
edges 72. The cutting edges 72, 74 are separated by between about
50-1500 microns, and most preferably 600 microns. In the embodiment
depicted in FIG. 6A, the donor tissue 10 is passed between the
first and second rollers 70a, 70b, which are rotating in opposite
directions around their respective axes of rotation 76a, 76b.
Alternatively, and as depicted in FIG. 6B, the rollers 70a, 70b
rotate in the same direction as they are pressed along the surface
80 of the donor tissue 10.
[0038] Still another embodiment, as illustrated in FIG. 7, of the
cutter 16 of the present invention consists of multiple microtomes
82 stacked and separated by a space 84 within the range of about
50-1500 microns, and most preferably 600 microns. The microtomes 82
are pressed against the donor tissue to achieve particles of the
size desired.
[0039] A further embodiment, shown in FIG. 8, of the cutter 16 of
the present invention, consists of a bundle 84 of capillary tubes
86 having sharpened edges 88. The edges 88 are pressed into the
donor tissue to extract particles of a size equivalent to the inner
diameter 90 of the capillary tube 86, which is in the range of
about 50-1500 microns, and most preferably 600 microns. An
elastomer (not shown), such as soft rubber, may be positioned
within each capillary tube 86 to aid in extraction of the particles
after they have been cut from the donor tissue 10. As the capillary
tube 86 is pushed into the tissue, the elastomer retreats from the
edges 88 of the tube 86, allowing the tissue to be cut. As pressure
is relieved, the elastomer returns to its original position within
the tube, pushing the cut tissue particles out of the tubes 86.
[0040] A cylindrical press 100, as shown in FIG. 9, may be utilized
to cut tissue into a desired size within the range of 50-1500
microns, or preferably 600 microns, after the donor tissue 10 has
been removed from the donor site 12. The press 100 is housed within
a housing 102 having an open proximal end 104 and a closed distal
end 106, which is closed by the press 100 itself. An elastomer 108,
such as rubber, is fixed to the press within the housing, and a
removable cap 110 is positioned along the open proximal end 104 for
catching the tissue particles after they have been cut. Multiple
blades 112 are fixed within the housing 102 between the elastomer
108 of the press 100, and the open proximal end 104. The donor
tissue 10 is placed within the housing 102 between the press 100,
which is removable, and the blades 104. As the press 100 passes
through the housing 102, the elastomer 108 contacts the tissue 10
and forces it into and through the blades 112. The particles,
having been cut to the desired size, are trapped within the cap
104.
[0041] Still a further embodiment of the cutter 16 is illustrated
in FIG. 10. The cutter may consist of multiple serrated discs 120.
Slots 122 are formed within the discs 120, which are positioned
along an axis 124. The discs 120 are fixed along the axis 124 such
that a space of between 50-1500 microns, or preferably 600 microns,
exists between each disc 120. A ring 126 of longitudinal blades 128
envelops the discs 120, and configured to pass between the
serrations of the discs 120. Previously excised donor tissue 10 is
placed between the discs 120, cutting them into the desired
particle size as the ring 126 is passed over the discs 120.
[0042] Extraction of the particles from the blades or edges 130 of
the cutter 16 is illustrated in FIG. 11. An elastomer 132 is
positioned within the space 134 between the blades or edges 130. As
pressure is exerted by the cutter 16 against the donor tissue 10,
the elastomer 132 retracts. The cut tissue trapped in the space 134
between the blades 130 is forced out from the space 134 as pressure
is relieved from the cutter 16 and the elastomer 132 returns to its
original position.
[0043] The present invention includes a method of processing
harvested donor tissue into micrograft particles within the size
range of 50-1500 microns, and most preferably 600 microns. A
further embodiment includes processing donor tissue to micrograft
particles between 50-1500 microns, and most preferably 600 microns,
directly at the donor site, and thereafter excising the particles
from their contact points at the donor site using traditional
means, such as a dermatome.
[0044] While the above description contains many specifics, these
should not be construed as limitations on the scope of the
invention, but rather as exemplifications of one or another
preferred embodiment thereof. Many other variations are possible,
which would be obvious to one skilled in the art. Accordingly, the
scope of the invention should be determined by the scope of the
appended claims and their equivalents, and not just by the
embodiments.
* * * * *