Cesarean section is one of the most common surgical operations in obstetrics, which is used to terminate pregnancy and improve the prognosis of the pregnant and infant. The Qingdao Municipal Hospital is a regional clinical center for the critical pregnant and puerpera. At present, the main types of cesarean section in the world include Stark cesarean section, ECS and classical cesarean section. How to reduce perioperative and postoperative morbidity has become an important factor for obstetricians to consider. In 1907, Frand proposed the ECS. In 1908, Latzko designed an approach to the lower uterine segment from the lateral vesical fossa, which was later modified by Norton, into a lateral ECS. In 1940, Waters also proposed an ECS from the top of the bladder into the lower uterine segment. The literatures about ECS at home and abroad mainly focus on the middle and late 20th century. After decades of clinical practice, nowadays there are few reports on the clinical data about ECS due to the difficulty of its implementation. Most of these studies discuss the issue technically and emphasize that these patients heal faster and require less pain relief. A prospective study also proved its safety 2. There was no significant negative effect on maternal or neonatal results, despite the longer operative time in the ECS group. In addition, it is also pointed out that there is not enough experience of routinely implement this technology 3,4
ECS has obvious advantages, including less pain, less invasive celiac by genital tract infection, less mechanical injury of organization structure, less intraoperative intravenous rehydration fluid demand. Postpartum maternal bowel sounds return early, which means earlier food intake and ambulation, benefit for maternal physical rehabilitation and milk secretion, effectively improving the breastfeeding rate 5. The integrality of peritoneum avoids the loss of ascites in the abdominal cavity, which is conducive to the correction of hypoproteinemia in some parturient women. At the same time, the use of antibiotics in ECS is shorter than that in TCS6, which is consistent with the conclusions obtained in this study. In addition, the important point of ECS is to avoid the adhesion of tissues and organs in the pelvic cavity after this operation, which reduces the passive impact on subsequent pregnancy and difficulty of subsequent cesarean section. Bladder injury is not unique in extraperitoneal approaches, with a total incidence of 0.44%7. However, for pregnant women previous with severe adhesions in pelvic and abdominal cavity, ECS can effectively reduce the increased surgical difficulty caused by adhesions effectively avoid these adhesions, and is of great help to shorten the operation time and reduce intraoperative blood loss 8.
There are three approaches of ECS to expose lower uterine segment: paravesical, supravesical and combined extraperitoneal cesarean. Paravesical approach was the fasted and most common choice. So, it is in our hospital since 1970s as a routine operation and up to now, and rich surgical experience and treatment methods accumulated. The advantage is less damage to the bladder. As we all know that it is difficult to find, identify and separate the bladder reflexed peritoneum. A large number of venous plexuses are distributed in the vesical fossa. The improper mechanical injury due to ECS is easy to cause bleed, vesical fossa inflammation, and the symptoms of pollakisurie. In addition, the extent of bladder reflexed peritoneum separation is limited, so it is more difficult to operate on the patients whose extension of lower uterine segments are insufficient.
Studies have shown that the postoperative pain score of ECS is lower, especially about the surgical incision and around, so is the lung function damage9,10. Except physiological uterine contraction and surgical incision pain, the stimulation of peritoneum and surrounding organs caused by blood, fetal fat and amniotic fluid entering the abdominal cavity during surgery, is also an important factor aggravating postoperative pain11,12. In this study, although the comparison between the two groups was not statistically significant, the P value was very close to 0.05, and a similar conclusion may be drawn if the pain score is further accurate and the number of subjects is increased. Furthermore, the degree of additional analgesia required by ECS was lower 10. The relief of postoperative pain is beneficial for puerpera to get more physical and psychological comfort, help puerpera to enhance the nursing of newborn and early discharge, shorten the length of hospital. While there was no significant difference in length of hospital between the two groups in this study, this was the result of a combination of several factors, including waiting for neonatal blood examinations and bed scarcity. Pain after cesarean section not only affects the maternal ability to take care of the newborn, but also negatively affects lung function. Reducing the frequency and amplitude of respiration and expectoration due to pain avoidance, as well as reducing the activity offbed, can lead to postoperative pulmonary complications 13. Irritant fluids such as amniotic fluid and blood may reach the diaphragm due to irrigation in TCS resulting in irritation that negatively affects lung function. on contrast, in a case of ESC, the peritoneal cavity does not enter air, maintaining the original pressure difference and inconspicuous peritoneal cavity expansion. The stimulation to the diaphragm is slight, so the influence on the postoperative lung function is unobvious.
Intestinal peristalsis is affected by the traction of the intestine, peritoneum suturing and intraluminal diffusion of amniotic fluid and blood during TCS6. Intraoperative peritoneal traction can also contribute to the symptoms of maternal nausea and vomiting 14. Intestinal function recovery can usually be assessed by listening to borborygmus with a stethoscope, and it can be heard earlier in the ECS group as well as gas passage15,16. ECS avoids stimulation of gastrointestinal function, enabling patients to resume diet more quickly, taking oral nutrition earlier, which contributes to early wound healing and postpartum recovery 17. Similar results were reported in a randomized trial, which showed that the average recovery of intestinal function was 8 ± 4 hours for ECS and 13 ± 4 hours for TCS6. In this study, gastrointestinal function recovery was assessed by gas passage time, and there was no significant difference between the two groups. The data collected were from nursing documents, only a few accurate gas passage time recorded, therefore there are certain errors in the data. However, according to the maternal subjective feedback, the gas passage time in the extraperitoneal group was earlier and the gas passage experience was better, which was consistent with the results of the previous study.
The traditional method of head delivery requires repeated pressure of the uterine fundus, which increases the pain of puerpera and may increase the rate of surgical complications, affecting the prognosis passively. The longer the time of fetal head delivery, the higher the risk of complications such as neonatal asphyxia and amniotic fluid inhalation syndrome caused by external stimulation to the fetus 18, so the fetal head should be delivered quickly after uterus incision and the respiratory tract should be fully cleaned. One of the key difficulties of ECS lies in the delivery of the fetal head. In this study, no significant effect presented on the measurable parameters of the newborn. The reason is that obstetric forceps were used in our hospital to deliver the fetal head. The left and right leaves of forceps are respectively placed on both sides of the fetal head and sufficient and smooth force is offered to deliver the head. It can shorten the duration of delivering fetal head effectively.
Admittedly the ECS group held a higher birth weight than the other group, but the duration of surgery was actually lower. A literature shows that the operation time of ECS is longer [10], which is contrary to the results of this study. First, our hospital has been taking ESC as a routine operation for decades. The surgeons are well-trained and experienced. Second, as mentioned above, the application of obstetric forceps accelerates head delivery. Third, after uterus sutured, the separated bladder only needs to be replaced to the original position and the peritoneum unstitching is not required, which reduces surgical steps and speeds up the operation compared with TCS.
The limitation of ECS mainly base on the operative skills required for surgeons and its performance in the routine application. Improper operation and inadequate prevention measures will rise the chance of surgical complications. The beginner of ECS always make these mistakes. In addition, ECS is more suitable for a pregnant woman in principle whose fetal head has entered the pelvis and the cervix has been opened 2–3 centimeter, because she has entered the labor course and her lower uterine segment has been fully extended. If ECS is taken as a routine operation, there are a large number of elective surgery women fail to try vaginal labor. Unextended lower uterine segment increases the difficulty of exposure and head delivery. The time from the beginning of the operation to the delivery of the fetus is longer than TCS, so it is not suitable for the cesarean section to rescue the newborn. Intraoperative exploration of the uterus, accessories and pelvic and abdominal cavity cannot be carried out during ECS, as a result, the pelvic and abdominal surgeries, such as tubal ligation and hysteromyoma resection, are unable to be conducted at the same time.