Tweetable abstract
Currently, there is no conclusive consensus regarding usage of adhesion
barriers at cesarean section. Previous studies of HA-CMC were performed
by different surgeons which affect background adhesion incidence, and
studies of ORC were limited to one small study. We are interested in the
adhesion rates under the minimal effect of confounding factors and the
postoperative outcome of different adhesion barriers. We found the use
of adhesion barrier at cesarean delivery didn’t improve adhesion
formation but had significantly higher rates of postcesarean fever. Our
result does not support application of anti-adhesion films during
cesarean deliveries especiallyin emergency cesarean section or in a
woman having labor before operation.
Introduction
Repeat cesarean section (CS) has led to more difficult surgeries,
secondary to adhesion found at delivery. The more often the abdomen is
entered, the more extensive and dense adhesion may be encountered.
Previous research reported prevalence of adhesion in 11.5–46% of women
at their second CS and 26–75% of women during their third CS
[1-11]. Adhesion has been linked in the delayed delivery of the
neonate, higher incidence of bladder or bowel injury, excessive
bleeding, and increased operative time during repeat
CS [10-13]. There are several
adhesion prevention barriers approved by the U.S. Food and Drug
Administration (FDA) for the prevention of postoperative adhesion. Two
commercially available barriers for CS such as HA-CMC (Seprafilm®) or
ORC (Interceed®) have been studied, and some retrospective and
prospective studies suggest that these barriers reduce the amount and
severity of adhesion formation and blood loss [14-21]. In our
experience, adhesion after the primary CS is generally minimal or
nonexistent. One randomized trial and two retrospective researches
demonstrated that HA-CMC applied during CS did not reduce adhesion
formation and affect operative outcome at repeat CS [22-24].
However, these studies of HA-CMC reported the data were from a
multicenter and CS were performed by different surgeons with
varying experience and surgical techniques (e.g., rectus muscle
approximation, uterine or peritoneal closure, packing the gutters) [3,
4, 25-30]. Second, they did not exclude the patient with history of
uterine incision or laparoscopy. These confounding factors affect
background adhesion incidence. Third, data regarding the use of ORC for
adhesion prevention during CS were limited to one small study. So we
executed a CS retrospective chart review performed by three physicians
with profound experience and similar surgical techniques. We evaluated
clinical efficacy of placement of the HA-CMC and ORC during primary CS
and assess surgical outcomes at primary and secondary CS.
Patients and Methods
We conducted a retrospective study between January1, 2011, and September
31, 2019. The study was reviewed and approved by the institutional
ethics committee of the MacKay Memorial Hospital (18MMHIS155e). The
study included all Asian women undergoing primary CS performed by the
three experienced surgeons (at least more than 20 years as an
obstetrician) at MacKay Memorial Hospital, a quaternary care referral
hospital at Taipei. Most patients received secondary CS by the same
surgeon, while a minority received the secondary operation by the other
two surgeons at or less than five years interval. Additional inclusion
criteria included the following: both deliveries were live neonates at
23–42 weeks of gestation, delivered through Pfannenstiel incisions,
intraperitoneal CS, and both hysterotomy with low transverse incision.
Exclusion criteria included the following: (a) American Society of
Anesthesiologists (ASA) score >3; (b) medical records
mentioning history of pelvic inflammatory disease or endometriosis; (c)
uterine incision (e.g., myomectomy, cesarean), open abdominal or
laparoscopic pelvic surgery before the primary or the secondary CS; (d)
tubal sterilization, ovarian cystectomy or myomectomy during CS.
Operative notes and electronic medical records on labor and delivery of
patients concerning the primary and the secondary surgical procedures
were used to obtain data on demographic data (maternal age, parity,
gestational age, body mass index (BMI), ASA score) and relevant data
from their medical and surgical history. We also collected the basic
characteristics and complications at each surgery, including
preoperative and postoperative laboratory data, estimated blood loss,
visceral organ injury, the description of adhesion, operative times, and
skin-to-delivery time.
Adhesion reduction agent in CS is the indication of HA-CMC or ORC in
Taiwan. Our pregnant women could choose to use anti-adhesion material or
not before undergoing operation. Preoperative skin preparation was done
and prophylactic and therapeutic antibiotics were given according to
local standards. After delivery, all uterus were closed in two layers,
and closure of the bladder flap and peritoneum and rectus muscle
approximation were also done. Abdominal irrigation or packing of bowel
was avoided during operation. HA-CMC or ORC was placed over the
incisional site and the midline anterior surface of the uterus. This was
usually completed with 1 sheet or cut into smaller pieces to facilitate
placement. Because there has not been a validated adhesion scoring
system to be used for cesarean deliveries, we evaluated adhesion that
was in the field of manipulation. Adhesion was scored as severe or mild,
if the operative summary contained the words severe ,extensive , vascular , and dense or if the operative
notes used words such as mild , few , filmy, andsome . The outcome measures were the incidence of adhesion,
skin-to-delivery time (defined as the time from skin incision to the
first neonate delivery), operative time (defined as the time from skin
incision to skin closure) during the secondary CS, estimated blood loss,
and rates of intraoperative (e.g., bladder or bowel injury,
hysterectomy, injury to uterine vessels, postpartum hemorrhage, or drop
of Hb) and postoperative complications (e.g., fever, ileus, incisional
wound infection, metritis, UTI, hospital length, readmission for SSI,
and the frequency of postpartum clinic visits) related to the repeat CS.
We also examine the short-term postoperative outcome (as repeat CS) of
the adhesion barriers placement at the primary CS as measured by
postoperative complications (e.g., postoperative white blood cell
count).
Sample size at each group was calculated based on studies performed by
Fushiki et al. [16] and Chapa et al. [19] for the endpoint of
adhesion formation. We estimated that a minimum of 20 patients in HA-CMC
group and 14 patients in ORC group would be required to detect these
differences with 80% power.
Statistical analysis was performed with R software, version 3.3.1 (R
Project for Statistical Computing, Vienna, Austria). Differences in
demographics among the three groups were assessed with the Student’st- test or chi-square as appropriate and the results for
continuous variables were given as the mean ± SD. Multiple logistic
regression was used to evaluate for SSI risk factors of postcesarean
fever at the primary CS. An interaction term analysis was performed to
examine the impact of SSI risk factors and use of adhesion barrier on
postcesarean fever rates at the primary CS. The magnitude of statistical
significance was expressed with Adj-HR and 95% CI. Statistical
significance was defined at the 95% level (P<0.05).
Results
A total of 236 patients were included in this study and 37 were excluded
due to one or more exclusion criteria. Finally, 99 women received the
HA-CMC, 26 women received the ORC, and 74 did not receive adhesion
barrier at the primary CS. There were no differences in patient
demographics or preoperative characteristics at the time of the primary
CS except for gestational age and preoperative white blood cell count,
which was highest in the nonuser group (Table 1). Table 2 shows
intraoperative characteristics including skin-to-delivery time, total
operative time, adhesion condition, intraoperative complications or
estimated blood loss, and neonatal birth weight, and there were no
significant differences among the 3 groups. It also contained
postoperative laboratory data includinghematocrit, drops of hematocrit
and white blood cell count, with no significant difference among the
groups. Similarly, there were no differences in the need of additional
therapeutic antibiotic, hospital length, readmission for SSI, and the
frequency of postpartum clinic visits. However, two patients who
received the HA-CMC adhesion barrier were readmitted to the hospital for
postpartum metritis. But both groups that used adhesion barrier had
significantly higher rates of postoperative fever compared with the
control group (HA-CMC 17.2% vs. ORC 15.4% vs. nonuse 5.4%,p =0.045).
Demographic data at the time of the secondary CS are shown in Table 3.
There were no significant differences among the groups except for
gestational age and the percentage of adhesion barrier use at the
secondary CS. Around 63% of nonuser at the primary CS chose to use
adhesion barrier at the secondary CS and 97% and 96.2% of the other
two groups chose to use adhesion barrier at repeat CS. There were less
than 40% of patients in labor and less than 20% of patients with
membrane rupture before operation in either group at secondary CS, while
there were50–70% of patients in labor and 40–60% with membrane
rupture before the primary CS. Table 4 shows adhesion and intraoperative
and postoperative outcomes at the secondary CS. Notably, there were no
differences as regards skin-to-delivery time, total operative time,
adhesion formation, bladder or bowel injury, hysterectomy, injury to
uterine vessels, estimated blood loss, or drop of Hb.
Since the use of adhesion barrier user at the primary CS had
significantly higher rates of postcesarean fever, the following SSI risk
factors relating to postcesarean fever were evaluated using logistic
regression: use of the adhesion barrier, labor or membrane rupture
before operation, emergency operation, total operative time, estimated
blood loss ≧500 cc, BMI ≧30 kg/m2, diabetes mellitus,
hypertension, or preeclampsia. All
nine risk factors were entered in a multiple regression and we found the
use of adhesion barrier at the primary CS as an independent risk factor
of postcesarean fever (p= 0.045, Adj-HR=3.53, 95% CI=1.03–10.24)
(Table 5). An interaction term analysis was performed to examine the
impact of SSI risk factors and use of adhesion barrier on postcesarean
fever at the primary CS (Table 6). The strongest risk factor for
postcesarean fever is the use of anti-adhesion filmduring emergency CS
(p= 0.041). Borderline interaction between labor before operation
and use of anti-adhesion filmmay play some role for postcesarean fever
(p= 0.054).In the subgroup of labor before operation and emergency
CS, adhesion barrier use had significantly higher risk of postcesarean
fever (labor before operation: user 21.2% vs. nonuser 2.2%,p= 0.018, Adj-HR=12.12, 95% CI=1.53–95.78; emergency CS: user
20.3% vs. nonuser 2.0%, p= 0.016, Adj-HR=12.71, 95%
CI=1.62–99.62).