Surgical adhesion barriers and methods of using such surgical adhesion barriers are provided. Surgical adhesion barriers according to the present invention have at least one layer of a bioabsorbable material comprising copolymers and/or block copolymers derived from trimethylene carbonate. Alternatively, a multilayer surgical structure having one or more bioabsorbable layers superimposed on a non-absorbable layer is useful for minimizing or preventing formation of fibrous adhesions between a healing trauma site and adjacent surrounding tissue. Alternatively, a bioabsorbable non-woven fabric in adherent contact with at least one bioabsorbable layer of foam, film, mesh, web or woven fabric is also provided. One or more medicinal agents may be interposed between or disposed within any of the aforementioned layers.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to minimization and/or prevention of 
post-surgical adhesions and more particularly, to devices and methods for 
preventing the formation of such adhesions between a healing trauma site 
and adjacent surrounding tissue. 
2. Description of Related Art 
Injury, surgical incision or abrasion to the peritoneum, pleural or 
abdominal cavity results in an outpouring of a serosanguinous exudate. The 
exudate subsequently coagulates, producing fibrinous bands between 
abutting surfaces which can become organized by fibroblast proliferation 
to become collagenous adhesions. Adhesions are also known to form at bone 
fracture sites where jagged, irregular bone edges form in the area of the 
fracture. Bony spurs promote the growth of fibrous adhesions between the 
bone fracture surface and surrounding tissue. 
Adhesion formation following surgery or trauma is generally considered to 
be undesirable. For example, adhesions that form in relation to intestinal 
surgery, e.g., bowel resection, hernia repair, etc. may cause obstruction 
of the intestine. Adhesions that form near the bone fracture site may 
reduce or hinder the normal movement of the area of repair by restricting 
the natural movement of tendons over the adjacent bone. Adhesions may also 
form in the vicinity of nerves and disrupt nerve transmissions with a 
resultant diminution of sensory or motor function. 
Various methods and substances have been used in the hope of preventing 
post-operative adhesions. Certain drugs and surfactants have been 
suggested. For example, U.S. Pat. No. 4,911,926 is directed to adhesion 
prevention by application of aqueous and non-aqueous compositions of a 
polyoxyalkylene block copolymer to injured areas of the peritoneal or 
pleural cavity or organs situated therein subsequent to surgical injury. 
Another approach to adhesion prevention involves application of a physical 
barrier at the area of surgical injury. U.S. Pat. No. 4,674,488 is 
directed to interposing a barrier layer of soft biological tissue, such as 
collagen, collagen-fabric films, collagen membranes, or reconstituted 
collagen or Dacron.RTM. mesh, at the interface of a bone fracture and the 
surrounding tissue. U.S. Pat. No. 4,603,695 is directed to a molded 
polymeric material for preventing adhesion of vital tissues. The polymeric 
material is made of a biodegradable and absorbable polymer such as certain 
polyesters, collagen, amino acid polymers and chitin and may be placed 
where there is a possibility of adhesion setting in. 
Other materials have also been used to form physical barriers in an attempt 
to prevent adhesions, including silicone elastomers, gelatin films and 
knit fabrics of oxidized regenerated cellulose (hereinafter ORC). In some 
cases, it is suggested that heparin, heparinoid, or hexuronyl 
hexosaminoglycan be incorporated into a matrix of ORC fabric or other 
matrices of hyaluronic acid, cross-linked and uncross-linked collagen 
webs, synthetic resorbable polymers, gelatin films, absorbable gel films, 
oxidized cellulose fabrics and films which are fabricated into a form that 
is said to be drapable, conformable and adherent to body organs and 
substantially absorbable within 30 days. See, e.g., U.S. Pat. No. 
4,840,626 or EPA Pub. No. 0 262 890 or EPA Pub. No. 0 372 969. 
Physical barriers are also used to cover and protect wound sites. 
PCT/US91/08972 is directed to a surgical article having a bioabsorbable 
fibrous matrix in a laminar relationship with a bioabsorbable cell barrier 
sheet. U.S. Pat. No. 5,092,884 and EPA Pub. No. 0 334 046 are directed to 
a surgical composite structure having absorbable and non-absorbable 
components which may be useful for repairing anatomical defects, e.g., 
preventing hernia formation in an infected area. The nonabsorbable portion 
of the composite acts as a reinforcement material. Ingrowth of natural 
tissue is said to be enhanced by controlled degradation of the absorbable 
portion. U.S. Pat. No. 5,035,893 relates to a wound covering composition 
having a sheet of biopolymeric material and a film of polyurethane resin. 
An antibacterial agent may be provided between the polyurethane film and 
the sheet of biopolymeric material, thereby forming a three-layer wound 
covering material. With the cure of the wound, it is said that the 
biopolymeric material is taken in a living tissue and the polyurethane 
film can be peeled off from the sheet without hurting the surface of a 
wound. 
SUMMARY OF THE INVENTION 
The present invention provides surgical adhesion barriers and methods of 
using surgical adhesion barriers which have at least one layer of 
bioabsorbable material. The bioabsorbable material comprises copolymers, 
block copolymers or blends thereof. The copolymers comprises carbonates 
and at least one other bioabsorbable polymer forming material. The block 
copolymers comprise at least one block comprising trimethylene carbonate. 
In one embodiment the block copolymer comprises a first block formed from 
a copolymer having a predominant amount of trimethylene carbonate and a 
second block formed from a copolymer having a predominant amount of 
lactide. 
In another embodiment, the present invention provides a multilayer surgical 
structure having one bioabsorbable layer affixed to a non-absorbable 
layer. Both the absorbable and the non-absorbable layer may be fashioned 
from mesh, web, woven fabric, non-woven fabric, porous film, non-porous 
film or foam. The structure is made by superimposing a layer of 
bioabsorbable material on a non-absorbable layer. In alternative 
embodiments subsequent bioabsorbable layers can be added. Additionally, 
one or more medicinal agents can be interposed between any of the 
aforementioned layers. 
In another embodiment, the present invention provides a multilayer surgical 
structure having a bioabsorbable non-woven fabric in adherent contact with 
one or more bioabsorbable layers which may be in the form of film, foam, 
mesh, web or woven fabric. 
The surgical adhesion barrier or multilayer surgical structure is flexible, 
resilient and conformable to various shapes such as body organs and 
tissues. During surgery, a surgical adhesion barrier according to the 
present invention is positioned at the area of injury to prevent adhesions 
as desired. Likewise, a multilayer surgical structure according to the 
present invention having absorbable and non-absorbable layers is 
positioned at the area of injury to prevent adhesions as desired. In the 
case of a multilayer adhesion barrier, the nonabsorbable layer is 
preferably positioned adjacent to the area of injury and the bioabsorbable 
layer(s) face away from the injury. As the bioabsorbable layer is 
absorbed, any adhesions which may have attached to the bioabsorbable layer 
lose their support and fall free of the injury site. 
In yet another embodiment, the multilayer surgical structure incorporates a 
plurality of bioabsorbable layers which bioabsorb at different rates. Each 
layer of bioabsorbable material is absorbed over time, thus exposing and 
releasing any medicinal agents which may be contained between layers. 
The structures of the present invention may find application for open 
general surgery or less invasive surgical techniques such as endoscopic 
surgery, or both.

EXAMPLE 1 
Copolymer of Glycolide/Trimethylene Carbonate 
(Polymer I) 
A 20/80 mole percent glycolide/trimethylene carbonate copolymer was 
prepared in a reactor by combining previously dried 53.13 grams of 
glycolide and 186.87 grams of trimethylene carbonate and polymerizing at 
160.degree. C. for 24 hours in the presence of 0.05 grams of stannous 
octoate. The polymer was extruded from the reactor and post treated to 
remove any residual monomer present in the polymer. The inherent viscosity 
of the polymer was 0.9. 
EXAMPLE 2 
Copolymer of Glycolide/Trimethylene Carbonate/Lactide 
(Polymer II) 
A block copolymer having one block containing 20 mole percent glycolide and 
80 mole percent trimethylene carbonate and another block containing 20 
mole percent glycolide and 80 mole percent lactide, wherein both blocks 
are present in equal weight ratios was prepared in a reactor. 553.4 grams 
of glycolide and 1946.6 grams of trimethylene carbonate were added to the 
reactor along with 1.0 grams of stannous octoate and dried under vacuum in 
the reactor for about 16 hrs. After drying, the reactants were heated at 
150.degree. C. and polymerized for about 24 hrs. At this stage 419.1 grams 
of dried glycolide and 2080.9 grams of Lactide were added and continued 
polymerizing of additional 24 hrs. The polymer is extruded and post 
treated to remove any residual monomers present in the polymer. The 
inherent viscosity of this polymer was 1.32. 
EXAMPLE 3 
Copolymer of Glycolide/Trimethylene Carbonate/Lactide 
(Polymer III) 
A block copolymer having 50% by weight of one block containing 40 mole 
percent glycolide and 60 mole percent trimethylene carbonate and 50% by 
weight of another block containing 20 mole percent glycolide and 80 mole 
percent lactide was prepared in a reactor. 646.7 grams of glycolide and 
853 grams of trimethylene carbonate were added to the reactor along with 
0.6 grams of stannous octoate and dried under vacuum in the reactor for 
about 24 hours at 160.degree. C. At this stage 251 grams of glycolide and 
1248 grams of lactide were added and polymerized for an additional 24 
hours at 170.degree. C. The polymer was extruded and post treated to 
remove any residual monomers present in the polymer. The inherent 
viscosity of this polymer was in the range of 0.4-0.8 dl/g. 
EXAMPLE 4 
Copolymer of Glycolide/Trimethylene Carbonate/Lactide 
(Polymer IV) 
A block copolymer having 20% by weight of one block containing 20 mole 
percent glycolide and 80 mole percent trimethylene carbonate and 80% by 
weight of another block containing 20 mole percent glycolide and 80 mole 
percent lactide was prepared in a reactor. 132.8 grams of glycolide and 
467.2 grams of trimethylene carbonate were added to the reactor along with 
0.6 grams of stannous octoate and dried under vacuum in the reactor for 
about 24 hours. At this stage 402 grams of glycolide and 1998 grams of 
lactide were added and polymerized for an additional 24 hours. The polymer 
was extruded and post treated to remove any residual monomers present in 
the polymer. The inherent viscosity of this polymer was of 0.6 to 1.1 
dl/g. 
EXAMPLE 5 
Construction of Multilayer Adhesion Barrier 
Polymer I, made in accordance with Example 1, was pressed into a film by 
means of a vacuum press supplied by Technical Machine Products, Cleveland, 
Ohio, a standard commercial press having PTFE coated platens. The 
temperature of the platens was maintained at about 130.degree. C. The 
platens were pressed together at a load of about 25,000 pounds for about 
12 minutes. The resulting film was then removed from the press. 
To bond the polymer film to a polypropylene mesh, the film was placed 
against the mesh and pressed together by the PTFE coated platens of a 
vacuum press supplied by Technical Machine Products, Cleveland, Ohio. The 
temperature of the platens was maintained at about 65.degree. C. and the 
platens were pressed together at a load of about 1000 pounds for about 5 
minutes. The multilayer adhesion barrier was then removed from the press. 
EXAMPLE 6 
Construction of Multilayer Adhesion Barrier 
Polymer II, made in accordance with Example 2,is pressed into a film in a 
manner similar to that described in Example 3 except that the platens were 
heated to a temperature of about 190.degree. C. and pressed together at a 
load of about 3000 pounds. 
To bond the polymer film to a polypropylene mesh, the film was placed 
against the mesh and pressed together by the PTFE coated platens of a 
vacuum press supplied by Technical Machine Products, Cleveland, Ohio. The 
temperature of the platens was maintained at about 120.degree. C. and the 
platens were pressed together at a load of about 3000 pounds for about 5 
minutes. The resulting multilayer adhesion barrier was then removed from 
the press. 
EXAMPLE 7 
Construction of Bioabsorbable Non-Woven Fabric 
A copolymer of about 18 mole percent glycolide and about 82 mole percent 
lactide was spun and drawn into a 40 filament 14 ply multifilament yarn. 
The plies were combined (1120 denier total) and crimped by stuffer box 
crimper. The crimped yarn was cut into staples of about 2 inches. The 
staple fibers were opened and carded on a carding machine and converted to 
a web having a basis weight of approximately 100 g/m.sup.2. Two web layers 
were needled together to form non-woven fabric (200 g/m.sup.2) which was 
washed in water for 5 minutes and dried in vacuum. The dried fabric was 
post treated at 90.degree. C. for 16 hours and then platen pressed at 
90.degree. C. for 12 seconds with 0.20 inch shims. The pressed non-woven 
fabric was postwashed in water for 5 minutes and dried in vacuum to yield 
a bioabsorbable non-woven fabric product. 
EXAMPLE 8 
Construction of Multilayer Adhesion Barrier 
Polymer III, made in accordance with Example 3, was dissolved in methylene 
chloride at room temperature while stirring until the mixture contains 
about 30 to about 50% and preferably about 35% solids. Transfer coating 
equipment was utilized to form an adherent bond between a non-woven fabric 
made in accordance with Example 5 and a film described herein. The line 
speed ran at 6 feet per minute. Oven temperatures were read at about 
112.degree. F. in the first zone, about 107 in the second zone and about 
110.degree. F. in the third zone. The web temperature was about 
119.degree. F. The polymer mixture, with a viscosity of about 500 CPS is 
coated onto moving release paper to form an approximately 2 mil film. The 
bioabsorbable non-woven fabric was placed onto the wet film. A light 
weight card board was placed on the fabric to maintain good adherent 
contact with the film. The film and fabric were then passed through the 
ovens. The solvent evaporated and a dry product having the film and fabric 
in adherent contact resulted. The release paper was peeled off the film 
side of the adhesion barrier. Alternatively, two layers of 1 mil film can 
be applied separately and adhered. By applying multiple layers, 
irregularities in the film layer, such as small holes, are less likely to 
be present in the final product. 
EXAMPLE 9 
Construction of Multilayer Adhesion Barrier 
An approximately 2 mil film of polymer III, made in accordance with Example 
8 is produced on release paper without non-woven fabric. After drying, the 
film was cut to desired, size and placed in contact with the film side of 
the adhesion barrier made in accordance with Example 8. The films 
inherently adhere to each other and a trilayer adhesion barrier was 
prepared with a manual laminator by feeding the film and the two-layer 
adhesion barrier into the laminator between movable rollers. 
EXAMPLE 10 
Implantation of Polymer I Adhesion Barrier 
Twelve female Sprague-Dawley rats weighing between 255-250 gm each were 
monitored for at least one week prior to surgery to insure good health and 
stability. The animals were anesthetized with intraperitoneal sodium 
pentobarbital and their abdomens prepared for surgery. The abdominal 
cavity was exposed through a midline incision. On the abdominal wall 
overlying the cecum, a 1 cm.times.2 cm area of parietal peritoneum was 
carefully excised from the abdominal wall, removing a thin layer of muscle 
along with the peritoneum. 
The cecum was elevated and isolated by moist gauze. The proximal end of the 
cecum was emptied of its contents. A 1 cm.times.2 cm area on the anterior 
surface of the proximal end of the cecum was gently abraded by rubbing 10 
times with dry gauze. The cecum was then scraped with a scalpel blade to 
cause minute petechial hemorrhages. The cecal abrasion was left exposed 
for 15 minutes. After 15 minutes, the cecal abrasion and the abdominal 
wound were blotted with a gauze sponge to gently remove any excess blood 
and ensure complete hemostasis. Placement of these two wounds together 
normally leads to reproducible formation of an adhesion. 
A 2 cm.times.3 cm film of Polymer I approximately 7 mil thick made in a 
manner according to Example 3 was placed between the wounds before they 
were placed in contact and the abdomen closed. The procedure was repeated 
on all twelve rats. 
Seven days following surgery, the animals peritoneum was evaluated for the 
development of an adhesion between the peritoneal defect and the cecal 
surface. Examination of the wound site revealed that one of twelve rats 
had developed an adhesion. 
EXAMPLE 11 
Implantation of Polymer II Adhesion Barrier 
Polymer II in accordance with Example 2 was formed into a single layer film 
approximately 7 mil thick and implanted in a manner similar to that 
described in Example 5. Examination of the wound site after seven days 
revealed that one of twelve rats had developed an adhesion. 
EXAMPLE 12 
Implantation of Polymer I/Polypropylene Mesh Adhesion Barrier 
1 cm.times.2 cm pads of SURGIPRO.RTM. polypropylene mesh (commercially 
available from U.S. Surgical Corp.) coated with a film of Polymer I were 
implanted into fifteen rats in a manner similar to that described in 
Example 5 except that certain different groups of the rats were analyzed 
at three specified time intervals: 7, 31 and 55 days, respectively. At day 
7 one of five rats developed a retroperitoneal fat adhesion; no cecal 
adhesions were observed. At day 21 two of five rats were observed with 
cecal adhesions. At day 55 none of five rats were observed with cecal 
adhesions. In sum, three of fifteen rats were observed with cecal 
adhesions at the wound site. 
EXAMPLE 13 
Implantation of Polymer II/Polypropylene Mesh Adhesion Barrier 
1 cm.times.2 cm pads of SURGIPRO.RTM. polypropylene mesh (commercially 
available from U.S. Surgical Corp.) coated with a film of Polymer II were 
implanted into fourteen rats in a manner similar to that described in 
Example 12. At day 7 none of five rats were observed with adhesions. At 
day 21 one of five rats was observed with a cecal adhesion. At day 55 none 
of four rats were observed with cecal adhesions. In sum, one of fourteen 
rats was observed with cecal adhesions at the wound site. 
EXAMPLE 14 
Implantation of Polymer II/Polypropylene Mesh Adhesion Barrier 
2 cm.times.3 cm pads of a 2 mil film of Polymer II bonded to Surgipro.RTM. 
polypropylene mesh (commercially available from U.S. Surgical Corp.) were 
implanted into thirty-six rats in a manner similar to that described in 
Example 10 except that the pads were sutured to the abdominal wall using 
size 7/0 polypropylene suture in each corner of the pad and that wound 
cites of three groups of twelve rats were analyzed for adhesions at 7, 14 
and 21 days, respectively, following implantation. After 7, 14 and 21 days 
none of the rats were observed with cecal adhesions at the wound site. 
EXAMPLE 15 
Implantation of Polymer II/Polypropylene Mesh Adhesion Barrier 
2 cm.times.3 cm pads of a 4 mil film of Polymer II bonded to Surgipro.RTM. 
polypropylene mesh (commercially available from U.S. Surgical Corp.) were 
implanted into twelve rats in a manner similar to that described in 
Example 14. After 7, 14 and 21 days none of the rats were observed with 
cecal adhesions at the wound site. 
EXAMPLE 16 
Implantation of Polymer II Film Adhesion Barrier 
2 cm.times.3 cm pads of a 2 mil film of Polymer II were implanted into 
thirty rats in a manner similar to that described in Example 14. After 7 
days the incidence of cecal adhesions was about 25% in twelve rats. Two of 
the cecal adhesions are believed to have been caused by technical error. 
At days 14 and 21 about an 11% incidence of cecal adhesions was observed, 
respectively, in two groups of nine rats. 
EXAMPLE 17 
Implantation of Polymer II Adhesion Barrier 
2 cm.times.3 cm pads of a 4 mil film of Polymer II were implanted into 
thirty-six rats in a manner similar to that described in Example 14. There 
were no cecal adhesions observed at day 7. At days 14 and 21, about an 8% 
incidence of adhesions was observed, respectively, in two groups of twelve 
rats. 
EXAMPLE 18 
Implantation of Polymer II/Polypropylene Mesh Adhesion Barrier 
Six Yorkshire gilts weighing between 38 and 46 kg received standard dosage, 
intramuscular injections of antibiotic and were anesthetized. A midline 
celiotomy incision was made and, on both sides of the body wall, an 
approximate 3.times.3 cm section of the peritoneum, the internal abdominal 
fascia and the abdominal wall muscle were removed. Each partial thickness 
defect was repaired with a SURGIPRO.RTM. polypropylene mesh (U.S. Surgical 
Corp.) coated with a film of Polymer II. A total of twelve abdominal wall 
defects were created and repaired, two per animal. 
The abdominal wall and defect repair sites were examined for the type and 
extent of adhesions after two weeks. Adhesions were observed at three of 
the twelve wound sites. 
COMATIVE EXAMPLE 1 
2 cm.times.3 cm Hyaluronic acid pads (commercially available from Med Chem) 
were implanted in seventeen rats in a manner similar to that described in 
Example 10. Examination of the wound site after seven days revealed that 
twelve of seventeen rats developed adhesions. 
COMATIVE EXAMPLE 2 
3 cm diameter Hylan NWM discs (commercially available from Biomatrix, 
Inc.), circulars disc containing hyaluronic acid, were implanted in eleven 
rats in a manner similar to that described in Example 10. Examination of 
the wound site after seven days revealed that two of eleven rats developed 
adhesions. 
COMATIVE EXAMPLE 3 
Hylan solution (commercially available from Biomatrix, Inc.), a hyaluronic 
acid gel, was applied to both wound surfaces of twelve rats caused in a 
similar manner as the wound surfaces created in Example 10. Seven of 
twelve rats developed adhesions at the wound site. 
COMATIVE EXAMPLE 4 
3% methylcellulose solution was applied to both wound surfaces of eleven 
rats caused in a similar manner as the wound surfaces created in Example 
10. Five of eleven rats developed adhesions at the wound site. 
COMATIVE EXAMPLE 5 
1 cm.times.2 cm pads of uncoated SURGIPRO.RTM. polypropylene mesh 
(commercially available from U.S. Surgical Corp.) were implanted into 
fifteen rats in a manner similar to that described in Example 10 except 
that certain of the rats were analyzed at three specified time intervals: 
at 7, 21, and 55 days, respectively. It is believed that one of the 
fifteen rats was mislabeled and discounted in the group analyzed at 7 
days; at day 7 three of four rats developed cecal adhesions; at day 21 
three of five rats developed cecal adhesions; at day 55 three of five rats 
developed cecal adhesions. In sum, nine of fourteen remaining rats 
developed cecal adhesions at the wound site. 
COMATIVE EXAMPLE 6 
1 cm.times.2 cm pads of SURGIPRO.RTM. polypropylene mesh (commercially 
available from U.S. Surgical Corp.) coated with film of 
hydroxyethylmethacrylate (HEMA) were implanted into fifteen rats in a 
manner similar to that described in Comparative Example 10. At day 7, one 
of five rats was observed with a cecal adhesion and three of the five rats 
were observed with retroperitoneal fat adhesions. At day 21 two of five 
rats were observed with cecal adhesions. At day 55 two of five rats were 
observed with cecal adhesions. In sum, five of fifteen rats were observed 
with cecal adhesions at the wound site. 
COMATIVE EXAMPLE 7 
Pads of Marlex.RTM. polypropylene mesh (commercially available from C.R. 
Bard., Inc.) were implanted into six defect sites created in gilts in a 
manner similar to that described in Example 18. Four of six defect sites 
were observed with adhesions. 
COMATIVE EXAMPLE 8 
Pads of Gore-Tex.RTM. mesh (commercially available from W.L. Gore & Co.) 
were implanted into six defect sites created in gilts in a manner similar 
to that described in Example 18. Three of six defect sites were observed 
with adhesions. 
COMATIVE EXAMPLE 9 
Pads of Interceed.RTM. oxidized regenerated cellulose (commercially 
available from Ethicon, Inc.) were implanted into six defect sites created 
in gilts in a manner similar to that described in Example 18. Two of six 
defect sites were observed with adhesions. 
COMATIVE EXAMPLE 10 
Six defect sites were created in gilts in a manner similar to that 
described in Example 18, but no implant was used at the defect site, i.e., 
the defects were unrepaired. Two of six defect sites were observed with 
adhesions. 
COMATIVE EXAMPLE 11 
2 cm.times.3 cm pads of Marlex.RTM. polypropylene mesh (commercially 
available from C.R. Bard, Inc.) were implanted into twelve rats in a 
manner similar to that described in Example 10 except that the pads were 
sutured to the abdominal wall using size 7/0 polypropylene suture in each 
corner of the pad. The stitches were placed so that the knots were under 
the sample and not exposed. After seven days, all twelve rats were 
observed with adhesions at the wound site. 
COMATIVE EXAMPLE 12 
2 cm.times.3 cm pads of Surgipro.RTM. polypropylene mesh (commercially 
available from U.S. Surgical Corp.) were implanted into twelve rats in a 
manner similar to that described in Comparative Example 11. After seven 
days, all twelve rats were observed with adhesions at the wound site. 
COMATIVE EXAMPLE 13 
2 cm.times.3 cm pads of Interceed.RTM. oxidized regenerated cellulose 
(commercially available from Ethicon, Inc.) were implanted into twelve 
rats in a manner similar to that described in Comparative Example 11. 
After seven days, all twelve rats were observed with adhesions at the 
wound site. 
COMATIVE EXAMPLE 14 
2 cm.times.3 cm pads of Gore-Tex.RTM. soft tissue patch (commercially 
available from W.C. Gore & Co.) were implanted into twelve rats in a 
manner similar to that described in Comparative Example 11. After seven 
days, eight of twelve rats (about 67%) were observed with adhesions at the 
wound site. 
Comparative Examples 7-14 also included observations of adhesions which are 
considered to be less important than cecal adhesions. Adhesions of lesser 
importance are categorized herein as Type 1, Type 2 and Type 3. Type 1 
include fat, liver, or intestines adhered to the face of the test surface. 
Type 2 include fat, liver, or intestines adhered to a free edge of a test 
surface or to suture knots. Type 3 include adherence of the cecal defect 
to peritoneal wall caudal or lateral to the test site. The results of the 
observations relating to adhesions of lesser importance are summarized in 
Table I. 
TABLE I 
__________________________________________________________________________ 
Incidence of adhesions other than the cecum 
adhering to the overlying test material. 
INCIDENCE OF OTHER ADHESIONS 
(APPROXIMATE %) 
DAY 7 DAY 14 DAY 21 
Type 
Type 
Type 
Type 
Type 
Type 
Type 
Type 
Type 
TEST MATERIAL 
1 2 3 1 2 3 1 2 3 
__________________________________________________________________________ 
SURGIPRO 100 
100 
0 N/A N/A 
MARLEX 100 
100 
0 
INTERCEED 92 * 0 
GORE-TEX 75 58 8 
SURGIPRO + 
0 100 
33 100 
42 33 92 17 42 
2 mil film 
SURGIPRO + 
0 100 
25 91 9 18 91 36 18 
4 mil film 
2 mil film 
0 92 25 0 78 11 0 89 22 
4 mil film 
0 83 17 0 75 0 0 100 
33 
__________________________________________________________________________ 
* Type 2 adhesions were not possible for Interceed since its edges were 
the same as its surface and the material was not sutured to the peritonea 
defect. 
The principles, preferred embodiments and modes of operation of the 
invention have been described in the foregoing specification. The 
invention which is intended to be protected herein, however, is not to be 
construed as limited to the particular forms disclosed, since they are to 
be regarded as illustrative rather than restrictive. Modifications and 
variations of the present invention are possible in light of the above 
teachings. It is therefore to be understood that changes may be made in 
particular embodiments of the invention described which are within the 
full intended scope of the invention as defined by the claims.