Michael A. Belfort
Cesarean delivery (CD) is abdominal delivery of the fetus through an incision in the uterus. Compared to vaginal delivery, CD is associated with increased potential for severe maternal morbidity and mortality, abnormal placentation in subsequent pregnancies, and neonatal respiratory morbidity. CD is performed when risks of vaginal delivery to the mother or fetus outweigh risks of CD.
CD is the most common major surgical procedure in the United States. In 2018, 31.9% of deliveries in the United States were by CD.
Heart and lung examination
Abdominal examination focusing on the following:
Prior abdominal incisions and scars, alerting the surgeon to prior surgeries or trauma with risk of intra-abdominal adhesions
Distribution of adiposity in obese patients that may also influence the choice of abdominal entry
Assessment of head, neck, and airway performed by anesthesiologist in case general anesthesia is anticipated or becomes required
The rate of CD rapidly increased from 1996 to 2011, prompting the publication of recommendations from professional societies with strategies to prevent primary CD. Acknowledging that some conditions such as placenta previa, accreta, and history of uterine rupture are absolute contraindications to vaginal delivery, the recommendations target other indications for CD where alterative management may allow for a safe vaginal delivery.
Analysis of modern labor progress showed that rates of cervical change may be slower than that suggested by the classic Friedman labor curve and that epidural anesthesia significantly prolongs duration of pushing. Definitions of arrest of labor in the first and second stages were thus updated in 2014 to reflect contemporary labor curves and allow more time before diagnosing an arrest of labor (1).
CD is only indicated for arrest of dilation for patients at or beyond 6 cm of dilation with ruptured membranes and 4 hours of adequate uterine contractions or 6 hours of oxytocin with inadequate uterine contractions and no cervical change.
In the setting of reassuring maternal status and fetal monitoring, multiparous patients should be allowed to push for 2 hours and nulliparous patients for 3 hours, with longer durations appropriate with epidural anesthesia or fetal malposition as long as progress is documented. The benefit of vaginal delivery must be weighed against the increased morbidity of CD after extended duration of pushing, with potential for increased maternal and neonatal morbidity with CD for arrest seen since implementation of the new labor management guidelines (2).
Other strategies to prevent CD because of arrest of descent include manual rotation of the fetal occiput in cases of fetal malposition and operative vaginal delivery. Operative vaginal delivery with vacuum or forceps for prolonged second stage, fetal compromise, or maternal medical disorders is considered a safe alternative to CD when performed by well-trained physicians for appropriate candidates.
With induction of labor and reassuring maternal and fetal status, CD may be avoided by not diagnosing a failed induction of labor until at least 12 to 18 hours of oxytocin administration after membrane rupture. In addition, with induction of labor and an unfavorable cervix, cervical ripening increases the likelihood of vaginal delivery.
Amnioinfusion in women with repetitive variable decelerations possibly due to cord compression decreases the rate of CD without worsening neonatal outcomes.
For noncephalic singleton fetuses, patients without contraindications should be offered an external cephalic version as an alternative to CD. The external cephalic version decreases the rate of primary CD.
Planned vaginal delivery is a safe alternative to planned CD for twin gestations, with appropriate concordance in weight, with the presenting fetus vertex at or after 32 weeks regardless of position of second twin, with an obstetrician experienced in vaginal breech delivery.
The preceding strategies target decreasing the rate of primary CD. Trial of labor after cesarean (TOLAC) is an alternative to elective repeat CD. Because failed TOLAC confers higher morbidity than does an elective repeat CD, assessing the likelihood of successful TOLAC is important for counseling patients and selecting optimal candidates. Women with a high likelihood of successful TOLAC and low risk of uterine rupture (prior low transverse uterine incision, one prior CD) are the best candidates. TOLAC should be performed in hospitals where emergency CD is available.
IMAGING AND OTHER DIAGNOSTICS
Perform bedside ultrasound to assess fetal presentation before nonlabored CD. Particularly with a transverse lie, assessing if the fetus is back up or back down may influence hysterotomy choice and delivery of the fetus. Ultrasound to assess placental location may allow the surgeon to avoid disturbing the placenta at hysterotomy.
Brief ultrasound before second-stage CD confirms fetal position to optimize head flexion at delivery and to evaluate location of limbs in case reverse breech delivery is required with an impacted head.
Fetal heart monitoring with a nonstress test before scheduled CD establishes fetal status before delivery. Monitoring may be discontinued after the nonstress test if the tracing is reactive and reassuring. For laboring patients, fetal heart monitoring should continue in the operating room (OR).
Laboratory testing for complete blood count and blood type is recommended to assess starting hemoglobin level and platelet count before placement of neuraxial anesthesia. For women at moderate risk for hemorrhage (postpartum hemorrhage [PPH]), perform a type and screen. For women at high risk for PPH, type and crossmatching is advised.
Women with congenital uterine anomalies require imaging of the urologic tract because 20% to 30% of those with Müllerian defects will have renal anomalies. Screen women during pregnancy with renal ultrasound if no prior imaging has been done. Unrecognized abnormal renal system anatomy may increase the risk of ureteral injury during CD.
Evidenced-based perioperative interventions for CD have been studied and a recently published Enhanced Recovery After Surgery (ERAS) protocol provides preoperative recommendations to reduce surgical morbidity (3).
Preoperative administration of antacids to neutralize gastric acid and histamine H2 receptor antagonists to prevent low gastric pH may reduce the risk of aspiration pneumonitis in women undergoing CD under general anesthesia. Because some women undergoing CD with regional anesthesia require conversion to general, the ERAS guideline recommends antacids and H2 antagonists for all CD; however, the evidence for this recommendation is low.
Previously, patients were counseled to have nothing to eat or drink after midnight before CD. Updated guidelines reflect evidence extrapolated to CD from other surgeries that showed no increase in complications with shorter durations of preoperative fasting. ERAS recommends clear liquids until 2 hours before CD and a light meal may be eaten up to 6 hours before CD.
Antibiotic administration with a first-generation cephalosporin in the 60 minutes before skin incision decreases the risk of postoperative infections. Women in labor or with ruptured membranes are at higher risk for infection and benefit from the addition of azithromycin.
Abdominal skin preparation with chlorhexidine-alcohol scrub is recommended on the basis of a randomized trial that showed decreased surgical site infections compared with povidone-iodine solution (4).
Vaginal preparation with povidone-iodine solution appears to decrease the risk of endometritis for CD performed in labor or after rupture of membranes.
CD increases the risk of venous thromboembolism (VTE) compared to vaginal delivery. For women at low risk for VTE, sequential compression devices during CD provide mechanical prophylaxis. On the basis of individual risk factors (history of VTE, thrombophilia, body mass index [BMI]), some women may require pharmacologic VTE prophylaxis following CD.
Depending on individual hospital factors and clinical situation, it may be beneficial to have red blood cells, fresh frozen plasma, and platelets in the OR before commencing CD for patients at high risk for PPH such as placenta previa unless blood products can be rapidly sent to the OR as in institutions with a massive transfusion protocol.
Maternal comorbidities, particularly cardiovascular, need to be assessed before CD. For women with high-risk cardiac conditions such as pulmonary hypertension or significant aortic dilation, planning for delivery includes determining safety of medications, hemodynamic monitoring requirements, delivery location, and postpartum recovery location.
All women require a preoperative consultation with an anesthesiologist before CD. For women with medical or obstetric (OB) issues that place them at elevated risk with CD, anesthesia consultation should occur before admission. For women without elevated risk, consultation may occur on the day of surgery.
Neuraxial anesthesia is generally preferred because it allows the mother to be awake for the delivery, facilitates postoperative pain control, and minimizes maternal morbidity, systemic administration of opioids, and transfer of medication to the fetus.
General anesthesia may be required when there is a maternal contraindication to neuraxial or failed or inadequate neuraxial block.
General anesthesia may also be required for emergency CD with insufficient time to place neuraxial anesthesia or reach a surgical level by bolusing a labor epidural catheter. With emergency CD, it is critical for OB and anesthesia providers to communicate about the urgency of the case to establish the best anesthetic technique for the situation.
Repeat CD is planned for the 39th week of gestation for women electing for a repeat CD with prior low transverse incision in the absence of OB or medical indications requiring earlier delivery. Planned repeat CD at 39 weeks allows for optimal fetal maturation and balances the risk of neonatal respiratory morbidity from early delivery with the risk of uterine rupture due to labor.
For women with a prior classic incision, repeat CD is recommended between 36+0 and 37+0 weeks. As a prior classic scar has a high risk of rupture with labor, the goal is to perform repeat CD in stable patients before the onset of labor while balancing risk of uterine rupture against risks of prematurity.
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The most common indications for primary CD are failure to progress during labor, nonreassuring fetal status, and fetal malpresentation.
Other indications include history of prior CD or uterine surgery, placenta previa, accreta, vasa previa, cord prolapse or funic presentation, mechanical obstruction to vaginal birth, uterine rupture, multiple gestation, suspected fetal macrosomia, selected fetal conditions, selected maternal comorbidities, and maternal request.
CD is usually performed in the dorsal supine position with a left lateral tilt to reduce aortocaval compression.
For CD for arrest of descent, a low dorsal lithotomy position may facilitate delivery of an impacted fetal head. Placing the patient’s legs in stirrups allows for improved ergonomics to elevate the head vaginally and may open the pelvis and facilitate ongoing evaluation of vaginal bleeding. Placing the patient in low lithotomy allows the obstetrician to assess for the risk of head impaction with a test lift before scrubbing for CD. Trendelenburg may also optimize delivery with an impacted head.
Preoperative education is important for women planning CD and for women planning vaginal delivery because almost one-third of primiparous women undergo CD.
Providing antenatal education and counseling allows patients to make an informed choice when CD is recommended and helps set expectations for postoperative recovery.
Procedures and Techniques
This section deals with the CD technique and encompasses two separate approaches. Traditional CD via Pfannenstiel or midline vertical incision is described in detail, followed by a less detailed description of a technique used in some institutions (Joel-Cohen technique).
Two types of skin incision are used for CD. Compared with midline vertical incisions, transverse incisions are associated with better cosmesis, decreased use of pain medication, and decreased risk of hernia (Tech Figure 4.6.1) (5).
Although transverse skin incisions are frequently preferred, midline vertical incisions may be performed in the following cases:
A transverse incision not providing adequate exposure such as for planned cesarean hysterectomy with placenta accreta
In obese patients with a large pannus or distribution of adipose tissue that makes a transverse incision more difficult and at higher risk for infection
For patients with a prior midline vertical incision who prefer the same incision to be used
Vertical incisions may be associated with decreased bleeding because the midline is less vascularized.
Some surgeons find that a midline vertical entry allows for a more rapid incision-to-delivery time in emergency CD when speed is critical. One study found that a vertical incision decreased median incision-to-delivery intervals from 4 to 3 minutes for emergency primary CD (6). Other surgeons find that because they perform more transverse skin incisions and are adept at them, a transverse approach leads to more rapid delivery. In cases of emergency CD when time to delivery is critical, surgeon preference for expediting delivery should guide type of skin incision.
The Pfannenstiel incision is the most commonly used transverse incision.
The pubic symphysis is palpated and the incision site is marked in the midline at 2 to 3 cm, approximately two fingerbreadths, above the top of the pubic symphysis.
Depending on patient body habitus and estimated fetal weight, an incision of 14 to 16 cm in length may be required. The linea nigra may be used to identify the midline and a skin marker used to draw the planned incision.
The incision is gently curved, with the lateral ends of the incision slightly more cephalad on the abdomen than in the middle.
A scalpel is used to make the incision. In cases of primary CD when minimal adhesions are anticipated, the pediatrics team may be called to the OR at the time of skin incision so that they will be prepared to receive the neonate by the time of delivery.
The midline vertical incision for CD is made with the scalpel from ˜2 cm above the pubic symphysis to 2 cm below the umbilicus in the midline. If more exposure is needed, the incision may be continued above the umbilicus, although this is uncommon except with cesarean hysterectomy.
The scalpel or electrocautery is used to incise the subcutaneous layer to the level of the fascia in the center of the incision horizontally with a Pfannenstiel or vertically with a midline vertical incision.
The goal is to make as few blade strokes as possible to reach the fascia directly, using the same incision and keeping the blade perpendicular to the skin. More strokes cause greater tissue damage and increase the susceptibility to infection. Angling the scalpel instead of keeping it perpendicular to the tissue leads to a fascial entry above or below the intended incision site.
The subcutaneous tissue is then cleared off of the fascia to the edges of the incision with blunt dissection or with sharp dissection when scar tissue is present.
With a Pfannenstiel incision, the tissue is opened from medial to lateral.
With a midline vertical incision, the tissue is opened superiorly and inferiorly.
The superficial epigastric vessels often found in the subcutaneous tissue near the lateral edges of a Pfannenstiel incision may be grasped with a Kelly clamp and cauterized to prevent bleeding (Tech Figure 4.6.2).
A Pfannenstiel incision is below the arcuate line, so the fascia of the anterior rectus sheath is composed of the aponeuroses of the external oblique, internal oblique, and the transversus abdominis muscles. The aponeuroses of the internal oblique and the transversus are fused and, thus, two layers of the fascial sheath are usually identified anterior to the rectus muscle.
The fascial incision has a semilunar shape similar to the skin incision (Tech Figure 4.6.3). First, the fascia is opened with the scalpel in the midline to the level of the rectus muscles on either side of the linea alba.
The external layer of the fascia is grasped with Bonney or single tooth forceps, undermined with the tips of the Mayo scissors, and then extended laterally with the Mayo scissors. This is repeated with the internal layer of fascia and on the contralateral side. The assistant uses a small retractor to pull the skin laterally and facilitate visualization. In repeat CD, two layers of fascia may not be clearly identified because of scarring and the fascia may be opened as a single layer.
The inferior epigastric artery and veins may be encountered between the two fascial layers as they travel within the rectus sheath overlying the lateral third of the rectus muscles. If the inferior epigastric artery is transected, grasp the vessel in the inferior edge of the cut layers of fascia with a hemostat and cauterize it. Then grasp the artery in the corresponding superior edge and cauterize it.
Midline vertical incision:
The midline fascia is identified where the fibers of each anterior rectus sheath join each other. The midline is incised with the scalpel vertically.
A hemostat is used to elevate the fascia, and the fascia is opened superiorly and inferiorly with electrocautery between the tips of the hemostat.
Dissection of Fascia From Rectus Muscles With Pfannenstiel Incision
The superior edge of the fascial incision is then grasped with Kocher clamps and elevated and the underlying rectus muscles are dissected off from inferior to superior with Mayo scissors in the midline where the fibrous linea alba attaches the fascia to the rectus (Tech Figure 4.6.4).
The attachment appears triangular, with the apex of the triangle pointing inferiorly. To remain in the correct plane, take bites beginning with the point of the triangle with the scissor blades angled parallel to the rectus.
In repeat CD due to scarring between the rectus and the fascia, the plane between the rectus and fascia may not be clear and light feathering strokes with the scalpel may be used to divide the rectus from the fascia, moving from inferior to superior.
The Kocher clamps are then removed and replaced on the inferior edge of the fascial incision. Blunt dissection is used to separate the fascia from the rectus, and Mayo scissors are used to separate the rectus from the fascia in the midline.
Separating Rectus Muscles
After opening the fascia, the rectus abdominis muscles will be visible, fused in the midline. Rectus muscles may generally be separated bluntly. In cases of scarring together of the muscles, the scalpel may be used to gently separate them in the midline (Tech Figure 4.6.5).
Tech Figure 4.6.4. The fascia is elevated with Kocher clamps and dissected off of the rectus muscles. (Reprinted with permission from Handa VL, Van Le L. Te Linde’s Operative Gynecology. 12th ed. Wolters Kluwer; 2019.)
Opening the Peritoneum
Fingers are then used to bluntly enter the peritoneum in a clear window. The peritoneum is entered as close to the upper abdomen as possible to avoid inadvertent injury to the bladder.
When the peritoneum is thickened, it may be grasped with smooth forceps, elevated, and entered in a clear space with Metzenbaum scissors.
Once the peritoneum is entered, the surgeon and assistant manually stretch the peritoneal opening by both pulling laterally at the angles of the peritoneal incision.
When pelvic adhesions are encountered, sharp dissection with Metzenbaum scissors may be used to open the peritoneum laterally. The peritoneum is preferentially opened laterally at the superior aspect of the incision to avoid potential adhesions to the bladder. Care is taken to avoid structures that may be fused to the peritoneum below. Meticulous small, shallow incisions are preferred when opening the peritoneum in the presence of dense adhesions.
The abdominal wall incision from skin to peritoneum is assessed to determine whether it is adequate to allow for easy delivery of the fetus. Layers that may impede smooth delivery of the fetus are opened to create adequate room. The size of the opening required depends on estimated fetal size and patient body habitus.
A transverse incision of the vesicouterine peritoneal fold to facilitate retraction of the bladder inferiorly, away from the lower uterine segment, has traditionally been performed with low transverse CD and referred to as creation of the bladder flap. The creation of the bladder flap is hypothesized to decrease the risk of bladder injury with hysterotomy by displacing the dome of the bladder inferiorly.
A meta-analysis of four randomized controlled trials including 581 women found no difference in bladder injury, total operating time, blood loss, or duration of hospitalization with or without the creation of a bladder flap (7). Omission of the bladder flap step decreased the skin incision-to-delivery interval by 1.27 minutes.
Bladder injury is a relatively rare outcome occurring in ˜0.3% of CD, but many surgeons create a bladder flap, particularly in repeat CD when the bladder may be adherent to the lower uterine segment or in a labored CD when the risk of bladder injury is higher.
Bladder injury is more frequent with intrapartum CD because the vesicouterine peritoneal reflection is pulled upward by the expansion and attenuation of the lower uterine segment with labor (Tech Figure 4.6.6).
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