Keywords
analgesia - cesarean - intestinal motility - parietal peritoneum - rectus abdominis
muscle
Introduction
The attainment of safe delivery for both mother and baby via cesarean section (CS)
is one of the important achievements of modern obstetrics. Cesarean section is one
of the most frequently performed operations in the world, and its frequency is increasing.[1]
[2] Cesarean section is defined as the delivery of the fetus by abdominal and uterine
incision. As with every surgical procedure, there are many variations in carrying
out CS, and the operation varies among surgeons. All stages of CS can be performed
with different techniques. The effort to compare the different procedures of CS and
to find a standard method of surgery has been ongoing for a long time.[3]
[4]
[5]
There are various studies comparing outcomes of closure and non-closure of the parietal
and visceral peritoneum, and rectus muscle reapproximation and no approximation. In
these studies, postoperative pain, need for analgesia, adhesion, infection, fever,
endometritis, and duration of hospitalization were examined,[5]
[6]
[7]
[8]
[9] and different results were obtained. Studies that compared postoperative pain and
need for analgesia focused on the reapproximation of the rectus muscle without comparing
parietal peritoneum closure or non-closure.[8]
[9] In addition, there is no study investigating the relationship between the postoperative
return of bowel motility and closure of the anterior abdominal wall layers.
In this study, we investigated the effect of closure types of the anterior abdominal
wall layers on postoperative pain, need for analgesia, and postoperative return of
bowel motility.
Methods
The present study was designed as a prospective cross-sectional study between October
2018 and February 2019 in patients undergoing their CS at a university hospital. This
study was conducted on patients who had standard CS surgical procedures in our clinic
and who were eligible for the study. Anterior abdominal wall closure patterns vary
from surgeon to surgeon in our clinic. This stage is implemented in three different
ways. Group assignments were made by browsing the operation notes. Each patient was
randomly assigned to one of these three groups:
-
Group 1: Both the parietal peritoneum and rectus abdominis muscle were left open;
-
Group 2: Parietal peritoneum closure only;
-
Group 3: Closure of the parietal peritoneum and re-approximation of rectus muscle.
The inclusion criteria were being at 37 or more weeks of gestation, not having systemic
disease, having standard CS procedures under spinal anesthesia. Elective CS patients
and patients in labor were included the study. The exclusion criteria included the
following: patients with preterm births (less than 37 gestational weeks); administration
of anesthesia besides general anesthesia; fetal distress; maternal hypertensive disorders;
maternal systemic diseases; preeclampsia; premature rupture of membranes; chorioamnionitis;
pregestational and gestational diabetes; placental invasion anomalies; coagulation
disorders; multiple pregnancies; renal, liver, and gastrointestinal disease; history
of > 3 previous CS; presence of dense adhesions; and psychiatric disorders.
Approval from the institutional local ethics committee was obtained, and each patient
provided a signed informed consent for their participation in the study. All staff
members (nurses and investigators) were blinded to the study groups, and all postoperative
procedures were made while remaining blinded. The health care provider who questioned
the patient about pain after the operation and medicated the patient did not know
which procedure was applied.
Postoperative Patient Follow-up
As a standard treatment in our clinic, we use intramuscular diclofenac for analgesia
for the first 24 hours (1 g every 8 h) and orally 3 times per day thereafter. In the
case of patients who describe pain (visual analogue scale [VAS] ≥ 30) in spite of
the treatment with diclofenac, we administer narcotics as an analgesic instead of
diclofenac. All patients receive preoperative prophylactic intravenous antibiotics
(cefazolin 2 g). Liquid food intake and mobilization of the patients are performed
at the 6th postoperative hour. The nursing staff monitor and record maternal blood
pressure, pulse activity, and urinary output hourly during the first 24 hours.
In the present study, postoperative pain was measured using a VAS (0 = no pain and
100 = worst pain ever). All mothers completed the VAS score at the 2nd, 6th, 12th, and 18th hours after surgery with the assistance of nursing staff. Pain scores were recorded
at the 2nd hour while lying down, and at other hours, pain scores were recorded both while the
patient was lying down and during mobilization. The time to return of bowel function
was recorded from the end of the surgery to the times of the first passage of flatus
and stool. No medical or mechanical intervention was performed for passing flatus
and stool. The patients were discharged at 48 hours postoperatively. No intervention
was used for patients who did not pass stool within 48 hours.
Surgical Technique
Cesarean section is performed in our clinic as described below. All CSs are performed
by the senior assistant. Nearly all surgeries are performed under spinal anesthesia.
A standard technique is used in all procedures. All women have a Pfannenstiel-type
transverse incision. The subcutaneous tissue layer is dissected using the fingers,
and then a small transverse incision is made, medially, with a scalpel and extended
laterally using scissors in the fascial layer. The rectus muscles are separated bluntly.
The peritoneum is opened with the forefinger. A bladder flap is formed, and a low
transverse incision is made in the uterus. The uterine incision is closed using a
single-layer continuous locked suture with a Vicryl 1.0 suture (Ethicon, Johnson &
Johnson, Cincinnati, OH, USA). The abdominal cavity is cleaned from amniotic fluid
and blood. The closure of the parietal peritoneum and rectus muscle in our clinic
varies according to the preference and experience of the surgeon. The parietal peritoneum
is closed using a continuous Vicryl 2.0 suture (Ethicon Johnson & Johnson). The rectus
muscles ere reapproximated using three loose vertical midline interrupted sutures
with Vicryl 2.0 sutures (Ethicon Johnson & Johnson). Sutures are placed about 1 cm
from the edge of the incision and 1 cm apart, without excessive tension. Subcutaneous
fat is closed when the tissue is thicker than 2 cm. Skin is reapproximated using a
continuous subcuticular suture with 2.0 polypropylene (Ethicon Johnson & Johnson).
All operative procedures are performed by the same surgeon. The day of CS is considered
as day 0.
Statistical Analyses
The G*Power 3.0.10 software (Franz Faul, Uni Kiel, Germany) was used for calculating
the sample size.[10] Sample size was calculated with an alpha of 0.05, a power of 80, and medium effect
size (f) 0.25. Given this calculation, the minimum required sample size was 53 patients
in each group. One hundred and eighty patients were included in the study. Statistical
analyses were performed using the IBM SPSS Statistics for Windows 21.0 software (IBM
Corp., Armonk, NY, USA). Parametric continuous data were presented as means ± standard
deviation, nonparametric continuous data were presented as medians (min–max). Categorical
variables were expressed as numbers (percentages). For statistical analysis, one-way
analysis of variance (ANOVA), Kruskal-Wallis, Mann-Whitney U, and Pearson chi-squared
tests were used, as appropriate; p < 0.05 was considered significant.
Results
A total of 180 women who underwent CS for various reasons, including planned repeated
cesarean delivery with up to maximum three previous CSs, were enrolled in the study.
All patients were similar in groups with respect to age, weight, and body mass index
(BMI).
Sixty women were allocated to each group. The most frequent indications for CS were
as follows: elective repeat CS, malpresentation, and macrosomia. The demographic and
physical conditions of the subgroups are summarized in [table 1]. Age, gravidity, parity, weight (before CS), weight (before pregnancy), weight gain
during pregnancy, height, and BMI (before pregnancy) were not significantly different
between the groups. The BMI (before birth) was significantly higher in group 2 than
in groups 1 and 3.
Table 1
Comparison of demographic characteristics and physical conditions
|
Group 1
N = 60
|
Group 2
N = 60
|
Group 3
N = 60
|
p-values
(among groups)
|
|
Age*
|
28 ± 6.1
|
30 ± 5.7
|
29 ± 5.7
|
0.495
|
|
Gravidity**
|
2 (1–6)
|
2 (1–6)
|
2 (1–8)
|
0.380
|
|
Parity**
|
1 (0–4)
|
1 (0–4)
|
1 (0–5)
|
0.782
|
|
Weight (before Caesarean section)*
|
78 ± 13
|
81 ± 14
|
77 ± 13
|
0.124
|
|
Weight (before pregnancy)**
|
65 (40–115)
|
68 (43–103)
|
63 (47–105)
|
0.177
|
|
Height*
|
162.4 ± 6.2
|
162.4 ± 5.8
|
162.6 ± 5.7
|
0.982
|
|
Weight gain during pregnancy**
|
10 (2–20)
|
11 (3–28)
|
11 (2–21)
|
0.124
|
|
BMI (before pregnancy)**
|
24.8 (18–40)
|
26.4 (16–38)
|
23.4 (18–38)
|
0.108
|
|
BMI (before birth)**
|
28.6 (21–40)[a]
|
30 (18–40)[a]
[b]
|
28 (20–42)[b]
|
0.030
|
*One-way analysis of variance (*) and Kruskal-Wallis (**) variance analysis as appropriate.
Bold values represent p < 0.05.
Data shown mean ± SD and median (minimum-maximum).
a P1< 0.05 versus P2 (Kruskal-Wallis, Mann-Whitney U-test).
b P2 < 0.05 versus P3 (Kruskal-Wallis, Mann- Whitney U-test).
The comparison of the groups in terms of the VAS of the subgroups is summarized in
[Table 2] and [Figure 1]. At the 2nd postoperative hour, the VAS was evaluated only while lying down, whereas at the other
times, it was evaluated while lying down and during mobilization. The postoperative
pain scores were similar at the 2nd, 6th, 12th, and 18th hours while lying down. During mobilization, the postoperative pain scores were different
between the groups at the 6th and 12th hours, and the pain scores at the 6th and 12th hours were significantly higher in group 2 than in group 3.
Fig. 1 Boxplot graphics of postoperative pain scores at the 6th and 12th hours during mobilization.
Table 2
Comparison of groups in terms of visual analog scale (VAS)
|
Group 1
N = 60
|
Group 2
N = 60
|
Group 3
N = 60
|
p-values
(among groups)
|
|
VAS 2nd hour
|
60 (10–100)
|
70 (10–100)
|
60 (10–95)
|
0.077
|
|
VAS 6th hour (lying down)
|
30 (0–90)
|
30 (0–70)
|
27.5 (0–80)
|
0.203
|
|
VAS 6th hour (mobilized)
|
50 (10–100)
|
50 (10–100)[b]
|
40 (10–90)[b]
|
0.029
|
|
VAS 12th hour (lying down)
|
20 (0–85)
|
27.5 (0–90)
|
20 (0–90)
|
0.201
|
|
VAS 12th hour (mobilized)
|
40 (5–90)
|
40 (5–100)[b]
|
40 (0–100)[b]
|
0.022
|
|
VAS 18th hour (lying down)
|
10 (0–40)
|
20 (0–50)
|
20 (0–50)
|
0.157
|
|
VAS 18th (mobilized)
|
27.5 (0–70)
|
30 (10–90)
|
30 (0–70)
|
0.188
|
Kruskal-Wallis (Mann-Whitney U-test) variance analysis as appropriate.
Bold values represent p < 0.05.
Data shown median (minimum–maximum).
b P2 < 0.05 versus P3.
The comparison of the groups in terms of analgesia requirements is summarized in [Table 3]. The use of diclofenac was significantly different between the groups, being higher
among patients in group 1. Meperidine requirements were similar in all groups. The
use of diclofenac in group 1 was found higher than in group 2. The first gas and stool
expulsion times for each group are summarized in [Table 4]. There was no difference between the groups' first flatus and stool passage times.
Table 3
Comparison of groups in terms of analgesia requirements
|
Group 1
N = 60
|
Group 2
N = 60
|
Group 3
N = 60
|
p-values
(among groups)
|
|
Diclofenac
|
1 (0–2)a
|
1 (0–2)a
|
1 (0–4)
|
0.043
|
|
Meperidine
|
1 (0–1)
|
1 (0–2)
|
1 (0–1)
|
0.177
|
Kruskal-Wallis variance analysis as appropriate; Bold values represent p < 0.05; Data shown median (minimum-maximum); aP1 < 0.05 versus P2 (Kruskal-Wallis, Mann-Whitney U-test)
Table 4
Comparison of groups in terms of first passage of flatus and stool times
|
|
Group 1
N = 60
|
Group 2
N = 60
|
Group 3
N = 60
|
p-values
(among groups)
|
|
|
Time to first pass flatus
|
16 (4–33)
|
16 (1–40)
|
14.5(2–41)
|
0.626
|
|
Before 24h
|
47 (31.8%)
|
52 (35.1%)
|
49 (33.1%)
|
0.486
|
|
24th hour and later
|
13 (40.6%)
|
8 (25.0%)
|
11 (34.4%)
|
|
Time to first pass stool
|
Before 24h
|
8 (27.6%)
|
13 (44.8%)
|
8 (27.6%)
|
0.265
|
|
24–48 hours
|
29 (31.2%)
|
27 (29.0%)
|
37 (39.8%)
|
|
48th hour and later
|
23 (39.7%)
|
20 (34.5%)
|
15 (25.9%)
|
Kruskal-Wallis and Pearson chi-Squared test; Data shown number (%) and median (minimum-maximum).
Discussion
The frequency of cesarean section is steadily increasing all over the world, as it
is in Turkey.[1]
[2]
[11] The CS rate, which was 14.3% in 1993, increased to 51.9% in 2013 in Turkey.[12] There is no standard method for CS in the world. There are many procedural differences,
from the opening to the closure of the skin incision.[13]
[14]
[15]
[16] We investigated the effect of the closure types of the anterior abdominal wall layers
on early postoperative findings of bowel motility in this study. Postoperative pain
scores at 6 and 12 hours were significantly higher in group 2 than in group 3 during
mobilization. Diclofenac use was significantly higher in patients in group 1 than
in group 2. Meperidine requirements were similar between the groups. There was no
difference between the groups in terms of first flatus and stool passage times.
When searching the literature, many studies comparing different stages of CS from
skin incision to uterine closure[4]
[7]
[8]
[14]
[17] were found. For example, Palatnik and Grobman[18] found that vertical incisions did not improve maternal and fetal outcomes, and Daykan
et al.[19] found that skin closure using glue or a monofilament synthetic suture had similar
results. With consideration to the closure of the uterus, Marceau et al. found that
two-layer closure was more effective than single-layer closure.[17] There are also studies suggesting that the risk of uterine dehiscence and rupture
has not changed.[20] In peritoneal closure, Kapustian et al.[7] found that closure of the parietal peritoneum did not change the adhesion ratio.[7] However, there are some studies showing that non-closure of the peritoneum is associated
with increased adhesions.[5]
[21]
There has been a long-standing hypothesis that there is a relationship between the
approximation of the rectus abdominis muscle and pain,[3]
[22] but, finally, two randomized controlled trials were recently published[8]
[9]; Lyell et al.[8] found that rectus muscle reapproximation increased immediate postoperative pain
without differences in operative time, surgical complications, or maternal satisfaction,
and Omran et al.[9] found that rectus muscle reapproximation among women undergoing primary CS was associated
with a significant increase in postoperative pain and analgesic requirements. Both
studies, however, focused on rectus muscle approximation versus no approximation and
did not examine its relationship with the closure and non-closure of the parietal
peritoneum. In our study, closure of the abdominal wall layers was examined as three
separate groups. Postoperative pain scores were found to be similar at the 2nd, 6th, 12th, and 18th hours while the patients were lying down. During mobilization, postoperative pain
scores were different between the groups at 6 and 12 hours. Pain scores at 6 and 12 hours
were found to be significantly higher in the parietal peritoneum closure group than
in the group undergoing both closure of the parietal peritoneum and reapproximation
of the rectus muscle. The approximation of the rectus muscle did not increase postoperative
pain and analgesia requirement.
Postoperative intestinal dysfunction is a physiologic response to abdominal surgery
and is more common in open surgery, such as CS.[11] Gastrointestinal dysfunction may cause abdominal discomfort due to the accumulation
of intestinal contents following CS and may cause a wide range of symptoms, such as
nausea, vomiting, or abdominal pain. For this reason, postoperative hospital stay
may be prolonged.[2]
[23] Few studies in the literature have examined the return of intestinal motility after
CS. The reason why some patients have early or late bowel motility and its relationship
to surgical technique has not been investigated. Studies examining the effect of gum
chewing and early oral feeding are available in the literature.[24]
[25] The aim of this study was to investigate the effect of a tighter closure of abdominal
compartment on intestinal motility after closure or non-closure of the rectus muscle
or peritoneum. We found that closure of the anterior abdominal wall had no effect
on bowel motility.
This prospective cross-sectional study ensured standardization of factors that could
affect postoperative pain. All women participating in our study received the same
intraoperative anesthesia, followed the same postoperative pain management protocol,
and underwent similar surgical techniques so as to reduce the number of potentially
confounding variables. Accordingly, we excluded patients with conditions that might
influence pain and bowel motility.
The limitations of this study include the follow-up of only postoperative short-term
results; the long-term results of aspects such as uterine involution, adhesions, and
diastasis recti were not studied. Also, the lack of questioning the patients' previous
pain conditions, having no data about the duration of surgery, blood loss, and episodes
of nausea and vomiting were other limitations. In addition, mobilization times that
could potentially affect gastrointestinal motility could not be controlled. The strength
of this study is that it is the first to investigate the effect of closure of the
anterior abdominal wall on the postoperative return of bowel motility.
Conclusion
In the group with only parietal peritoneum closure, the pain scores at the 6th and
12th hours were higher. Rectus abdominis muscle reapproximations were found to not
increase the pain score. The closure of the anterior abdominal wall had no effect
on the return of bowel motility. Whether or not the anterior abdominal wall is closed
has no effect on bowel motility and analgesia requirement. The studies that consider
analyzing directly intraabdominal pressures, intestinal motility time, mobilization
time of the patient and measuring pain scores more objectively can give more consistent
results.
