There is no standard technique for Caesarean Section.Several steps of Caesarean Section are discussed in the following paragraphs.
A transverse incision is preferred over a vertical midline incision.The advantages are:- (a)better cosmetic appearance ,(b) possibly less postoperative pain and (c)hernia formation .But vertical midline incision can be used in following circumstances.
Two common transverse incisions for cesarean delivery are the Pfannenstiel type and the Joel-Cohen type incisions
This method allows faster abdominal entry, causes less bleeding and superficial nerve injury, and can be easily extended cephalad if more space is required for access. In severely obese women, a supraumbilical vertical incision may be preferable to a subumbilical vertical incision.
There are no randomized trials comparing techniques for incision and dissection of the subcutaneous tissues at cesarean delivery. One can adopt either a blunt dissection with fingers or a sharp dissection with the knife.
A small transverse incision is usually made medially with the scalpel, and then extended laterally with scissors. Alternatively, the fascial incision can be extended bluntly by inserting the fingers of each hand under the fascia and then pulling in a cephalad-caudad direction.
Rectus muscles is usually separated bluntly in most cases. But whenever needed,transsection of muscles (ie, Maylard technique)can be done.Leaving the muscles intact preserves muscle strength in the early postoperative months.Several studies do not advocate the commonly performed procedure of dissection of the rectus fascia from the rectus muscles (2)
The peritoneum may be opened either by blunt dissection with fingers or by sharp dissection.One should be careful about inadvertent injury to bowel, bladder, or other organs that may be adherent to the underlying surface.In a large randomized trial (CORONIS) that examined five elements of the cesarean delivery technique in intervention pairs, there was no significant difference between blunt and sharp technique for the primary composite outcome of maternal death, infectious morbidity, further operative procedures, or blood transfusion >1 unit (3).
If there are dense adhesions between the anterior abdominal wall and the anterior surface of the uterus the abdomen should be entered as close as possible to the upper abdomen to avoid these areas. Other approaches are to start laterally or use a paravesical or supravesical extraperitoneal approach to avoid dense midline adhesions .
If pelvic adhesions require extensive dissection with risk of injury to the bowel, urinary tract, or major blood vessels to expose the lower uterine segment, and the patient desires tubal ligation, hysterotomy may be performed in the most appropriate accessible location.
The full thickness abdominal wall incision should be adequate to allow easy delivery of the fetus. A 15 cm incision is probably the minimal length that allows atraumatic and expeditious delivery of the term fetus (1)
The uterine incision is usually transverse but may be vertical. The principal consideration is that the incision must be large enough to allow atraumatic delivery of the fetus. Factors to consider include the position and size of the fetus, location of the placenta, presence of leiomyomas, development of the lower uterine segment, and future pregnancy plans.
The advantages of the transverse incision are less blood loss, less need for bladder dissection, easier reapproximation, and a lower risk of rupture in subsequent pregnancies (1).
The major disadvantage of the transverse incision is that significant lateral extension is not possible without risking laceration of major blood vessels. A "J" or inverted "T" extension is often required if a larger incision is needed.
The major disadvantage of the low vertical incision is the possibility of extension cephalad into the uterine fundus or caudally into the bladder, cervix, or vagina. It is also difficult to determine whether the low vertical incision is truly low, as the separation between lower and upper uterine segments is not easily identifiable.
A vertical incision in the upper uterine segment is termed a classical incision. This incision is rarely performed now a days as it ios associated with a higher frequency of uterine dehiscence/rupture & more maternal morbidity (4).
However it is used in following indications:
After the uterine cavity is entered, the incision is extended using blunt expansion with the surgeon's fingers or bandage scissors. In a 2014 systematic review/meta-analysis of six randomized trials of blunt versus sharp hysterotomy, blunt expansion resulted in a lower rate of unintended extensions (pooled relative risk [RR] 0.47, 95% CI 0.28-0.79) and a lower drop in hemoglobin and hematocrit postpartum, and shortened operative time by two minutes (5).
Delayed cord clamping results in higher neonatal hemoglobin levels and iron stores and facilitates the fetal to neonatal transition. It appears to be particularly beneficial for preterm newborns, but is recommended for term newborns as well. Early skin to skin contact between mother and newborn appears to promote breastfeeding and may help with physiological stabilization .
It is hypothesized that spontaneous expulsion allows the uterus time to contract and thus close myometrial sinuses. It also avoids potential contamination of open sinuses from any bacteria on the surgeon's gloves (6).So a manual extyraction is usually avoided.Oxytocin is used to enhance uterine contractile expulsive efforts and allow spontaneous placental expulsion.In a systematic review of randomized trials, manual extraction resulted in a higher rate of postoperative endometritis (RR 1.64, 95% CI 1.42-1.90), greater blood loss (weighted mean difference 94 mL, 95% CI 17-172 mL), a higher rate of blood loss over 1000 mL (RR 1.81, 95% CI 1.11-2.28), and lower postpartum hematocrit (7). To ensure that the entire placenta has been removed, the uterus is usually wiped with a gauge sponge to remove any remaining membranes or placental tissue. This maneuver may also stimulate uterine contraction.
A 2015 meta-analysis of randomized trials of extraabdominal (exteriorized) versus intra-abdominal (in situ) repair found no clinically significant differences in blood loss, intraoperative nausea, vomiting, return of bowel function, or pain between the two approaches, although some statistical differences were noted (8).
Short-term maternal outcomes are similar for single- and double-layer closure, except a single-layer closure takes less time. In a 2014 systematic review and meta-analysis of comparative studies, single- and double-layer hysterotomy closure resulted in similar rates of overall maternal infectious morbidity, endometritis, wound infection, and blood transfusion, but operative time was six minutes shorter with the single-layer closure (20 studies including almost 15,000 patients(9).
Over the long term, however, uterine rupture in the next pregnancy is a potential risk of single-layer closure. In a 2017 systematic review and meta-analysis of nine randomized trials (3969 pregnancies), single- and double-layer uterine incision closure resulted in a similar incidence of cesarean scar defects (25 and 43 percent, respectively; RR 0.77, 95% CI 0.36-1.64), uterine dehiscence (0.4 and 0.2 percent, respectively; RR 1.34, 95% CI 0.24-4.82), and rupture in a subsequent pregnancy (0.1 percent for both; RR 0.52, 95% CI 0.05-5.53), but single-layer closure resulted in thinner residual myometrial thickness on postpartum ultrasound (mean difference -2.19 mm, 95% CI -2.80-1.57) (10). Available data were of low quality due to imprecision and indirectness and thus do not provide convincing evidence of safety or harm. Compared with an unlocked closure, locked closure has been associated with higher occurrence of surrogate markers of scar weakness (thinner myometrial thickness, bell-shaped uterine wall defects) [53,54] and dehiscence/rupture (11).
In a 2014 meta-analysis of randomized trials, visceral and peritoneal non-closure decreased operative time by an average of approximately 6 minutes (12). However, the effect of non-closure on adhesion formation remains unclear because of the small number of patients who have undergone follow-up at a second cesarean delivery. Non-closure might allow the enlarged uterus to adhere to the anterior abdominal wall or impede spontaneous closure of the peritoneum, while closure might cause a foreign body reaction to sutures and tissue damage. In a 2009 systematic review of prospective observational studies of peritoneal non-closure at cesarean delivery, non-closure was associated with greater adhesion formation than closure of the parietal layer or both visceral and parietal layers (OR 2.6, 95% CI 1.48-4.56; three studies, n = 249) (13). But another large, well-designed trial that randomly assigned 533 women at primary cesarean to peritoneal non-closure or closure found no significant difference between groups in the proportion of patients with adhesions at any site or time from incision to delivery at repeat cesarean (n = 97 repeat cesareans) (14).