Module on “Caesarean section (Part-2)” by Dr. Vishwesh BN

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CESAREAN DELIVERY (Part-2)

Procedure of LSCS

A brief knowledge of anatomy before a caesarean delivery:

To achieve a cesarean delivery, the surgeon must traverse all the layers that separate him/her from the fetus. First, the skin is incised, followed by the subcutaneous tissues. The next layer is the fascia overlying the rectus abdominis muscles. The anterior abdominal fascia usually consists of two layers. One is composed of the aponeurosis from the external oblique rectus muscle, and the other is a fused layer which contains the aponeuroses of the transverse abdominis and internal oblique muscles. After separating the rectus muscles, which run from cephalad to caudal, the surgeon enters the abdominal cavity through the parietal peritoneum.

In a gravid woman, unlike in a nongravid patient, the uterus is often encountered at this point immediately upon entry into the abdomen. If the patient has adhesive disease from prior surgeries, the surgeon may encounter adhesions involving such structures as the omentum, the bowel, the anterior abdominal wall, the bladder, and the anterior aspect of the uterus.

Upon identification of the uterus, the surgeon then can identify the vesico uterine peritoneum, or vesicouterine serosa, that connects the bladder and the uterus. If the surgeon desires to make a bladder flap, he or she must incise the vesicouterine peritoneum. In a patient with prior cesarean sections, the bladder may become difficult to separate from the uterus.

The uterus consists of the serosal outer layer (perimetrium), the muscle layer (myometrium), and the inside mucosal layer (endometrium). All three of these layers are incised to make the uterine incision or hysterotomy. It is important to recall that the uterine vessels run along with the lateral aspects of the uterus on both sides, and care must be taken to avoid damaging these blood vessels when the uterine incision is either made or extended.  The uterine arteries branch from the anterior division of the internal iliac artery. The blood flow through these arteries is eight times faster during pregnancy, with a unilateral flow of over 300 ml per minute at 36 weeks. The uterine arteries cross the ureters anteriorly and enter the uterus at the cardinal ligament. The uterine arteries anastomose in the broad ligament with the ovarian arteries, which arise from the abdominal aorta.

Depending on the status of the patient’s amniotic membranes (if her “water is broken” or intact), the surgeon could encounter that amniotic sac upon incision of the uterus. The amniotic sac consists of two layers, the chorion, and the amnion, which fuse early in pregnancy. The amniotic sac, if present, would be the last layer between the surgeon and the fetus. It is at this point that the fetus is delivered, achieving the primary goal of the cesarean section.

Procedure of LSCS:

Once the patient is on the surgical table, the surgical drape is fenestrated around the patient’s abdomen. The initial skin incision can be made either in a supra pubic transverse or midline vertical fashion. A vertical midline incision is considered to provide faster access to the abdominal cavity, and it disrupts fewer tissue layers and vessels, leading to many citations as the preferred method to perform an emergency cesarean. A vertical incision may also allow visualization away from known severe adhesive disease. In the case of a planned cesarean hysterectomy for a morbidly adherent placenta, a vertical incision may provide more surgical exposure, as well as access to the hypogastric arteries. However, a transverse skin incision is the most commonly used and is preferable in most cases due to improved wound healing and patient tolerability.

A Pfannenstiel skin incision is slightly curved and is located 2 to 3 centimeters or 2 fingerbreadths above the symphysis pubis. The midportion of the incision is within the hair-bearing area of the mons. The hair should be removed in this case. A Joel-Cohen incision, in contrast, is straight rather than curved. It is 3 cm below the line connecting the anterior superior iliac spines, making it more cephalad than a Pfannenstiel skin incision.

The subcutaneous layer is next, and it can be dissected bluntly or sharply. Blood vessels course through this layer, so care should be taken to minimize blood loss by limiting sharp dissection to the midline until the fascia is reached, then bluntly dissecting laterally. Alternatively, judicious use of cautery can maintain hemostasis if blood vessels are transected.

The fascia is then incised in the midline with the scalpel, and this incision is extended laterally either sharply or bluntly. The fascia may then be dissected off the underlying rectus muscles. To accomplish this dissection, both the superior and inferior aspects of the fascia are sequentially grasped with a clamp (such as a Kocher), and dissection can be accomplished with a combination of blunt technique as well as sharply using scissors or cautery. Care is necessary not to damage the underlying rectus muscles. Although, in some clinical scenarios, the rectus muscles may be deliberately cut to provide better surgical access.

After separating the rectus muscles in the midline, entry into the abdominal cavity is achieved through opening the peritoneum. The surgeon can do this either sharply or bluntly. If utilizing sharp entry, care should be taken to avoid injury to underlying structures such as the bowel. Once the entry is achieved, the peritoneal incision is usually extended bluntly. Care is necessary to prevent injury to the bladder during the extension of the peritoneal incision.

A bladder blade is often placed at this point to provide visualization of the lower uterine segment. Alternatively, a self-retaining retractor is an option. The bladder flap can be created at this point if so desired; the peritoneum overlying the bladder and lower uterine segment is grasped and incised, and the bladder is dissected off the lower uterus sharply or bluntly. Surgeons choosing to create a bladder flap do so out of a desire to decrease surgical injury to the bladder, especially during repair of the uterine incision.

With adequate visualization, whether or not a bladder flap has been created, the uterine incision can now be made. The uterus incision can be either transverse or vertical. For most cesareans, a low transverse incision is preferable. Compared to a classical incision, and low transverse incision causes less bleeding, is easier to repair, and causes less adhesion formation.  A low transverse incision can also be extended vertically to create a “T,” “U,” or “J” incision to provide additional room.

Upon achieving uterine entry, the uterine incision can be extended laterally either bluntly with fingers or sharply with bandage scissors. Blunt extension of the uterine incision in a cephalad-caudad fashion is preferred if possible, as a sharp extension is associated with increased maternal morbidity and blood loss.

Delivery of the fetus in the vertex presentation is achieved by inserting a hand into the uterine cavity and elevating the fetal head into the hysterotomy. If the head cannot be elevated, an assistant may provide additional elevation from below via a hand in the patient’s vagina. Alternatively, a vacuum cup or a single forceps blade may be utilized to elevate the fetal head. After elevating the fetal head into the incision, the bladder blade is removed, and fundal pressure is applied to expel the fetus out of the uterus. The surgeon continues to guide the head gently during the process, and the surgical assistant may be instrumental in providing most of the fundal pressure. If fundal pressure is inadequate, or if it cannot be adequately achieved (such as significant maternal obesity), a vacuum cup can be applied to the fetal head for an assisted delivery. Forceps can also be placed at the time of cesarean delivery. The usual rules apply when utilizing vacuum or forceps, even in cesarean delivery.

If the fetus is in the breech presentation, the surgeon identifies the fetal lie by palpation inside the uterine cavity. There are several techniques for delivering a breech fetus, either by grasping the feet or the hips to bring the fetus into the hysterotomy. The fetus can be delivered to the level of the shoulders with gentle traction, sometimes with the assistance of a surgical towel around the fetus. The bilateral arms are sequentially swept down and delivered. Fundal pressure is then utilized to help flex and deliver the fetal head.

After delivery of the fetus, the umbilical cord is doubly clamped and cut. After cutting the umbilical cord, cord blood can be collected if necessary or desired. The placenta is then delivered; this can be accomplished via manual removal or spontaneously via cord traction and fundal massage. After delivering the placenta, the uterus gets cleaned with moist laparotomy sponges.

For the repair of the hysterotomy, the uterus can be exteriorized or left in situ. As for the repair itself, a delayed absorbable suture is used in a running fashion, taking care to incorporate the corners of the incision while avoiding the lateral vessels. A running closure decreases operating time and blood loss compared to interrupted closure. Once the uterus is closed, and hemostasis assured, the posterior cul-de-sac is cleared of blood and clot using laparotomy sponges and/or suction. This step may be omitted if the uterus has not been exteriorized. With the uterus returned to the abdomen, the abdomen again gets cleared of blood and clot. With the bladder blade reinserted, the hysterotomy repair is again visualized and made hemostatic if necessary. The bladder blade is again removed.

The peritoneum can be reapproximated at this time. Closure of the peritoneum adds operative time, and it may increase postoperative fever and length of hospital stay. Before the closure of the fascia, the rectus muscles and the subfascial tissues are inspected to ensure hemostasis. The rectus muscles can be reapproximated in advance of fascial closure. The fascia is then closed using delayed-absorbable suture in a running nonlocking fashion. The subcutaneous tissues are then irrigated, and hemostasis is assured. Closure of the subcutaneous space is recommended if the thickness if 2 cm or more, as this decreases the risk of hematoma, seroma, wound infection, and wound separation.

Skin closure may be accomplished using a variety of methods, the most common being surgical staples or subcuticular suture.

Assessment

  1. Name the types of abdominal incisions used in a caesarean delivery.

The major types of incisions involved in a caesarean delivery are a vertical or a transverse skin incision. Vertical incision may be infraumbilical midline or paramedian. Transverse incision, modified Pfannenstiel is made 3 cm above the symphysis pubis.

  1. What are the advantages of Transverse Abdominal Incision (Modifed Pfannenstiel Incision)?

Advantages of the Transverse Abdominal Incision include:

  1. Postoperative comfort is more
  2. Fundus of the uterus can be better palpated during immediate postoperative period
  3. Less chance of wound dehiscence
  4. Less chance of incisional hernia
  5. Cosmetic value

3. What are the advantages of the low transverse uterine muscle incision?

Ease of operation; less bladder dissection, less blood loss, easy to repair, complete reperitonization, less adhesion formation, less risk of scar rupture when trial of labor is given for subsequent delivery  are some of the advantages of the low transverse muscle incision.

  1. What are the other types of uterine incisions?

The other types of uterine incisions include:

  • (a) Lower vertical
  • (b) Classical incision (upper segment).
  • (c) “J” incision—the upward vertical extension of the initial transverse incision.
  • (d) Inverted “T” incision
  1. Describe in brief the procedure of delivery of the head in a caesarean delivery.

The procedure of delivery of the head is as follows: The membranes are ruptured if still intact. The blood mixed amniotic fluid is sucked out by continuous suction. The Doyen’s retractor is removed. The head is delivered by hooking the head with the fingers which are carefully insinuated between the lower uterine flap and the head until the palm is placed below the head. The head is delivered by elevation and flexion using the palm to act as a fulcrum. As the head is drawn to the incision line, the assistant is to apply pressure on the fundus. If the head is jammed, an assistant may push up the head by sterile gloved fingers introduced into the vagina. The head can also be delivered using either Wrigley’s or Barton’s forceps.

  1. Describe in brief the procedure of delivery of the trunk in a caesarean delivery.

As soon as the head is delivered, the mucus from the mouth, pharynx and nostrils is sucked

out using rubber catheter attached to an electric sucker. After the delivery of the shoulders, intravenous oxytocin 20 units or methergine 0.2 mg is to be administered. The rest of the body is delivered slowly and the baby is placed in a tray placed in between the mother’s thighs with the head tilted down for gravitational drainage. The cord is cut in between two clamps and the baby is handed over to the paediatrician. The Doyen’s retractor is reintroduced.

  1. What should be the optimum interval between uterine incision and delivery and why?

The optimum interval between uterine incision and delivery should be less than 90 seconds. Interval > 90 seconds are associated with poor Apgar scores. There is reflex uterine vasoconstriction following uterine incision and manipulation.

  1. Describe briefly the method of removal of the placenta and membranes.

By the time the baby is delivered in a caesarean delivery, the placenta is separated spontaneously. The placenta is extracted by traction on the cord with simultaneous pushing of the uterus towards the umbilicus per abdomen using the left hand (controlled cord traction). Routine manual removal should not be done. Advantages of spontaneous placental separation are: less blood loss and less risk of endometritis. The membranes are carefully removed preferably intact and even a small piece, if attached to the decidua should be removed using dry gauze. Dilatation of the internal os is not required. Exploration of the uterine cavity is desirable.

  1. Describe the method of Suture of the uterine wound.

The uterine incision is sutured in three layers-

First layer: The first stitch is placed on the far side in the lateral angle of the uterine incision and is tied. The suture material is No “0” chromic catgut or vicryl and the needle is round bodied. A continuous running suture taking deeper muscles excluding or including the deciduas (very difficult to exclude) ensures effective apposition of the tissues; the stitch is ultimately tied after the suture includes the near end of the angle.

Second layer: A similar continuous suture is placed taking the superficial muscles and adjacent fascia overlapping the first layer of suture.

Uterine muscles may be closed using a continuous single layer stitch taking full thickness muscle and decidua. There is controversy as regard the place of single layer or double layer closure in relation to the risk of subsequent scar rupture. The peritoneal flaps may be apposed by continuous inverting suture (to prevent any raw surface).

  1. Mention the important steps in lower segment cesarean section.
  • Preoperative preparation
  • Anesthesia: general or spinal or epidural
  • Antiseptic painting (povidone iodine 7.5%) and draping.
  • Skin incision — suprapubic transverse (commonly used).
  • Opening up of the peritoneal cavity — Doyen’s retractor is introduced.
  • Peritoneal incision →lower segment transverse incision → uterine muscle incision →lower segment transverse.
  • Delivery of the head: The membranes are ruptured →The Doyen’s retractor is removed. The hand is insinuated and the palm is placed below the head. The head is delivered by the hand → suctioning of the baby’s mouth is done.
  • Delivery of the trunk of the baby is done slowly. The cord is cut in between two clamps. The baby is handed over to the pediatrician/nurse. The Doyen’s retractor is reintroduced.
  • Delivery of the placenta and membranes slowly and completely.
  • Repair of the uterine wound.
  • Concluding part: The mops placed inside are removed and the number verified. Peritoneal toileting is done and the blood clots are removed meticulously. The tubes and ovaries are examined. The abdomen is closed in layers. The vagina is cleansed of blood clots and a sterile vulval pad is placed.

Reading Resources:

  1. Sung S, Mahdy H. Cesarean Section. [Updated 2020 May 5]. In: StatPearls [Internet]. Treasure Island (FL): Stat Pearls Publishing; 2020 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK546707
  2. Berghella V, Baxter JK, Chauhan SP. Evidence-based surgery for cesarean delivery. Am. J. Obstet. Gynecol. 2005 Nov;193(5):1607-17.
  3. Cecilia Bottomley and Janice Rymer. 100 cases in Obstetrics and Gynaecology. 2nd edition. Series editor: Janice Rymer. CRC Press: Taylor & Francis Group; 2015.
  4. Andrew T. Raftery, Michael S. Delbridge, Marcus J.D. Wagstaff and Katherine I. Bridge, Editors: Churchill’s Pocketbooks Surgery. 5th Elsevier; 2017
  5. Hiralal Konar Editor: Textbook of DC Dutta’s obstetrics. 8th New Delhi: Jaypee Brothers Medical Publishers; 2015.
  6. Hiralal Konar Editor: Dutta’s Bedside Clinics and Viva-Voce in Obstetrics and Gynecology. Sixth Edition. New Delhi: Jaypee Brothers Medical Publishers; 2016.
  7. Sakshi Arora. Pre Neet Obstetrics and Gynaecology. First Edition. New Delhi: Jaypee  Brothers Medical Publishers; 2013.
  8. Narendra Malhotra, Pratap Kumar, Jaideep Malhotra, Neharika Malhotra Bora and Parul Mittal M. Revised and updated. Jeffcoate’s Principles Of Gynaecology. Eighth Edition New Delhi: Jaypee Brothers Medical Publishers; 2014.
  9. Sarala Gopalan, S.Rathnakumar and Vanita Jain editors. Mudaliar and Menons Clinical Obstetrics. 7th Revised Edition. Orient Longman, Bombay.
  10. Keith Edmonds. Editor .Dewhurst’s Textbook of Obstetrics & Gynaecology. Seventh edition, Blackwell Publishing; 2007.

 

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