Surgical Science, 2013, 4, 401-404
http://dx.doi.org/10.4236/ss.2013.49078 Published Online September 2013 (http://www.scirp.org/journal/ss)
Influence of Peritoneal Suture on the Formation
of Abdominal Adhesions in Wistar Rats: Is
Nathália Andrade1, Michel Vinagre1, Luciana Can a ba r r o2, Willy Marcus França3*
1Faculty of Medical Science and Health, Catholic University of São Paulo, São Paulo, Brazil
2Faculty of Medical Science and Health, Pontifical Catholic University of São Paulo, São Paulo, Brazil
3Laboratory of Experimental Surgery, FCMS, PUC/SP, São Paulo, Brazil
Received March 24, 2013; revised April 25, 2013; accepted May 2, 2013
Copyright © 2013 Nathália Andrade et al. This is an open access article distributed under the Creative Commons Attribution License,
which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Purpose: The purpose of the present study was to determine the effect of peritoneal closure on the formation of ab-
dominal adhesions by verifying their degree of damage on intestinal portions and the omentum with the abdominal wall.
Given the different reports found in the literature concerning peritoneal closure mostly in obstetrics and gynecology,
any objective information based on statistically tested results may be of great value in the everyday surgery practice.
Material and Method: This is an experimental model on which a laparotomy is performed on the free cavity of the
abdominal wall in growing rats. Young Wistar rats (approximately 1 month old) were operated through a long median
xipho-umbilical abdominal incision. The animals were divided in 3 groups with fifteen rats each: in Group I, only the
peritoneum was left open and all the other layers of the abdominal wall were closed; the rats in Group II had their peri-
toneums closed with unabsorbable cord (Prolene 4-0, Ethicon®). The abdominal wall of the rats in Group III (control)
was only opened up to the musculature. The peritoneum, which remained intact and closed, was carefully prodded with
the grip of tweezers to avoid lesions and/or perforations in the peritoneum. Results: There were no deaths nor incisional
dehiscence and/or hernias among the animals. Nine animals of Group I presented adhesions (60%), whereas there were
adhesions in all the fifteen animals of Group II (100%). In Group III adhesions were found in two animals (13%). The
percentage of adhesions in Group II was significantly higher than those observed in Groups I and III (p < 0.0001). Ad-
hesions were mostly formed by the abdominal omentum. It was not observed any effect of the procedure on viscera.
Conclusion: The experimental model that was suggested is appropriate for the establishment and study of peritoneal
adhesions. The rate of adhesions found in the Group II was significantly higher (p < 0.0001) than the rate observed in
the Group I and Group III, suggesting that peritoneum suture can play a important role in the adhesion processes.
Keywords: Abdominal Adherence; Incision Closure; Peritoneal Suture
The need for peritoneum closure has been discussed for
many years. Increase of operative time and formation of
abdominal adhesions raise questions concerning the per-
formance of this procedure . Besides being one of the
main causes of intestinal obstruction, affecting particu-
larly the small intestine , which is related to the type
of surgery and the extension of peritoneal damage, adhe-
sions may also affect fertility and cause chronic abdomi-
nal pain . Reoperations are more complicated when
abdominal adhesions are present, and increase surgery
time and the risk of iatrogenic intestinal lesion. Moreover,
the chances are that it may be impossible to perform a
laparoscopy on the patient in the future .
The ongoing discussion about peritoneal closure has
engaged gynecologists, obstetricians and surgeons for
years [4,5]. Despite the assertion in several studies that
there is no statistical difference between peritoneal clo-
sure and non-closure in lower abdominal incisions (cae-
sarean sections) [4,5], some authors have shown signifi-
cant results in favor of peritoneal non-closure, such as
intraoperative time and hospitalization period (p < 0.01)
*Corresponding author. According to McNally and Curtain  the incidence of
opyright © 2013 SciRes. SS
N. ANDRADE ET AL.
adhesions in a group of patients who had their perito-
neum closed when they were submitted to caesarean sec-
tion was 28%, whereas in the group of patients whose
peritoneum wasn’t closed 14% had adhesions. In the
group whose peritoneum remained opened, the operative
time was 44.1 minutes, while in the group who had their
peritoneum closed the operative time increased to 52.2
minutes (p = 0.05) .
Weerawetwat et al.  also described that in women
submitted to caesarean section with and without perito-
neum closure no statistically significant differences were
observed between the groups with regards to complica-
tions and adhesions, despite the higher incidence in the
group whose peritoneum was closed .
Given that there is no consensus in the literature about
the need or usefulness of peritoneal suture, the aim of
this study is to clarify its effect on the formation of peri-
toneal adhesions in the abdominal cavity using Wistar
rats as the experimental model. In order to observe and
analyze the intra-abdominal adhesions on the suture cord,
the animals of the three groups were re-operated fourteen
days after the first surgery. The three groups were com-
pared with regards to the presence of abdominal adhesion
by applying the chi-square test for 2 × N tables.
2. Materials and Methods
Forty five 30-day-old Wistar rats weighing between 150
and 200 grams were used in this study. After a 24-hour
acclimation in the FCMS/PUC-SP vivarium, the animals
were submitted to general anesthesia with a 0.2 - 0.5 ml
intraperitoneal injection of Ketamine base −50mg/ml
(Ketalar®-Cristália do Brasil)and Xylazine 10 mg/ml
(Coopazine®-CoopersBrasilLtda) using an insulin needle.
Bupivacaine at 0.5% without a vasoconstrictor was in-
jected intramuscularly around the incision which keeps
the animal under local anesthesia for up to 2 hours .
Sterile surgery fields were set after asepsis procedures
with chlorhexidine aqueous solution. After the rats were
anesthetized, they were submitted to a median xipho-
umbilical laparotomy (Figure 1). The peritoneum was
opened with scissors following the same direction of the
wall incision. The intestinal portions were manipulated
for 2 - 3 minutes to simulate the surgery manipulation
that exposes the peritoneum to the surroundings and de-
hydration. Subsequently, the peritoneum was closed with
an anchor continuous suture made with a cord chosen by
the study group:
Group I: composed of 15 rats whose peritoneum re-
mained open, and the other layers of the abdominal wall
Group II: composed of other 15 rats that had the
peritoneum closed with unabsorbable cord (Prolene 4-0,
Figure 1. Animal in Group I. Note the primary suture line
(black arrows), the median incision cicatrization line (2
weeks later), and Prolene® 4-0 cord (red arrow). The second
incision was opened to show intestinal portions, it was cut
parallel to the previous incision to expose the adhesions.
Group III: represented by 15 rats whose abdominal
wall was only opened up to the musculature. The perito-
neum, which remained intact and closed, was externally
rubbed for approximately 2 - 3 minutes.
Two weeks after the surgical procedure the rats were
re-operated to verify if there were adhesions. Another
incision was cut parallel to and at about 2 - 3 cm on the
left side of the first incision. The entire wall was re-
tracted and examined for the presence of adhesions.
The chi-square test for 2 × N  was used to statisti-
cally compare the three groups with regards to the pres-
ence of adhesions.
There were no deaths nor incisional dehiscence and/or
hernias among the animals. Only one animal of Group II
(suture with Prolene®) presented intraperitoneal sangui-
nolent liquid. However, this animal was prostrated and
macroscopic hematuria was detected before euthanasia.
Macroscopically, the peritoneum of all animals was in-
tact, smooth and shiny.
Nine animals of Group I whose peritoneum was not
sutured presented adhesions (60%), whereas there were
adhesions in all the fifteen animals of Group II (100%)
that had their peritoneum sutured with Prolene®. In
Group III adhesions were found in two animals (13%)
One hundred percent of the animals in Group II that
had the peritoneum sutured with Prolene® presented ad-
hesions when compared with the other two groups, with
ax2 of 23.14. The percentage of adhesions in Group II
was significantly higher than those observed in Groups I
and III (p < 0.0001).
Adhesions were mostly formed by the abdominal
omentum. It was not observed any effect of the proce-
dure on viscera (Figures 2 and 3).
Copyright © 2013 SciRes. SS
N. ANDRADE ET AL. 403
Figure 2. Animal of Group I. The image shows the unsu-
tured peritoneum, only muscular layers of the abdominal
wall were sutured. Note Prolene® blue stiches through
Figure 3. Animal in Group II. Peritonium was sutured with
an unabsorbable cord (Prolene®). Note Prolene® blue stich-
Table 1. Group I is composed of animals whose peritoneum
was opened, but was not sutured; the peritonium of the
animals in Group II was sutured with Prolene® 4-0 and the
peritoneum Group III animals w as not ope ne d.
Percentage of adhesions in the 3 groups.
GROUP YES NO
TOTAL % ADHESIONS
I (No suture) 9 6 15 60
II (Prolene) 15 0 15 100
III (Control) 2 13 15 13
TOTAL 26 19 45 62
Having a vast impact on the patients’ quality of life and
health care costs 1, postoperative adhesions are the main
cause of intestinal obstruction and complicated reopera-
tions , accounting for more than 40% of all cases and
60% to 70% of those involving the small bowel . Pa-
tients submitted to laparotomy have 90% risk of devel-
oping intra-peritoneal adhesions and 5% - 20% incidence
of re-hospitalization due to adhesion formation 1and also
with effects on fertility and chronic pain .
This is the main reason for the ongoing discussion
about peritoneal closure; yet, research is mostly focused
on obstetric patients [4,5]. The reconstitution of the ab-
dominal wall anatomy, tissue approximation for better
cicatrization, decreased risk of infection by restoring the
peritoneal barrier, decreased risk of dehiscence and inci-
sional hernia, and also decreased abdominal adhesions
are some of the positive outcomes attributed to peritoneal
closure [7,11-13]. On the other hand, faster cicatrization
of the abdominal wall and decrease of operative time are
described as the advantages of the no-suture approach
Microscopically, the postoperative peritoneal adhe-
sions were the result of fibrin effusion after a lesion or
tissue inflammation with an initial phagocyte wave
cleaning up the traumatic debris, and a secondary fibro-
blast wave healing the lesion and differentiating into new
mesothelium cells [14,15]. Most of the fibrotic tissue
formed is resorbed within five days. However, in some
cases organization with fibroblast and capillary growth
may develop, resulting in fibrotic adhesion especially if
physiological fibrinolysis doesn’t occur in five to seven
days [11,12]. The main anatomo-pathological aspect of
peritoneal adhesion is the presence of tissue ischemia
[11,12], which would be the result of adhesion formation
for revascularization of the areas where blood supply was
impaired by the surgical act, given that tissue ischemia
decreases plasminogen activation . The establish-
ment of adhesion may also occur due to other reasons,
such as: trauma, infection, thrombosis and presence of
foreign bodies . Other possible risk factors with re-
gards to the development of adhesions include patient’s
age (under 60 years old), previous laparoscopy in less
than five years, peritonitis, multiple laparotomies, emer-
gency surgeries, omental resection and penetrating ab-
dominal trauma, particularly through stab .
Nagele et al.  presented different conclusions and
suggest that routine peritoneal closure should be dis-
carded, despite its low morbidity with regards to fever
and infection [15,19]. In a prospective randomized study
performed by Grundsell et al. , significant results were
found that support the peritoneal non-closure approach
concerning intraoperative time and hospitalization period
(p < 0.01) , however, the authors do not mention
McNally M. et al. , concluded that closing the peri-
toneum in caesarean section is not necessary, and that the
procedure can even result in adhesion formation . Na-
Copyright © 2013 SciRes. SS
N. ANDRADE ET AL.
Copyright © 2013 SciRes. SS
gele et al.  also suggested that routine peritoneal
closure should be discarded, despite its association with
low morbidity related to fever and infection .
On the other hand, Cheong et al.  concluded in an
extensive literature review that there are no differences
between peritoneal closure and non-closure in lower ab-
dominal incisions with regards to comorbidities such as
infections, fever and peritoneal adhesion formation,
among others . Weerawetwat et al.  also described
that in women submitted to caesarean section with and
without peritoneum closure there are no statistically sig-
nificant differences, despite their higher incidence in the
group whose peritoneum was closed .
In the present study, it was observed a higher inci-
dence of peritoneal adhesions in animals whose perito-
neum was sutured (Group II, 100%) when compared to
the group whose peritoneum was not sutured (Group I,
60%). These results contrast with Cheong et al.  con-
clusion, who asserted that there are no significant differ-
ences between suturing and not suturing the peritoneum.
The animals in Group III (Control group), were only
opened up to the musculature and the peritoneum re-
mained intact and had only 13% of adhesions.
The experimental model that was suggested is appro-
priate for the establishment and study of peritoneal adhe-
The rate of adhesions found in the Group II was sig-
nificantly higher (p < 0.0001) than the rate observed in
the Group I and Group III.
Special thanks to the FCMS/PUC-SP Vivarium team. To
the Biologist Luciana Canabarro, assistant at the Labora-
tory of Surgery Technique & Experimental Surgery for
her invaluable work with the animals.
This study was performed with the support of a
PIBIC-CNPq scholarship, N. 122.775/2010-4.
This project was sponsored with a scholarship by
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