Cesarean Section

Foreword

Surgery is required for the correction of some reproductive tract problems or for the use of special procedures. This chapter presents the most common surgical techniques used in the female camelidae. Special attention is given to the indications and surgical approach.

Indications

Cesarean section is indicated in many instances where normal delivery of a live or dead fetus is impossible.^{(2-4, 8, 12)} The most common reasons for delivery by cesarean section in camelidae are as follows:

*    Large fetus: emphysema or anasarca
*    Malformed fetus (ankylosis of carpus or tarsus, schistosomas reflexus)⁽²⁾
*    Immature parturient with a small pelvis, feto-matemal disproportion and failure of fetotomy⁽¹⁵⁾
*    Improper dilation of the cervix
*    Mummified fetus, fetal maceration⁽⁶⁾
*    Narrow pelvic canal due to presence of space-occupying lesions.
*    Uterine torsion^{(2, 5, 9, 10)}
*    Malposition, malpresentation, or bad posture which are difficult to correct (such as breech presentation,⁽¹⁵⁾ forelimbs crossed over the neck,⁽²⁾ lateral deviation of the head and neck.⁽⁷⁾

Cesarean section in llamas and alpacas

Cesarean section in the South American camelidae can be performed either via a flank laparotomy or a ventral midline approach. Cesarean section is usually an emergency operation. Preparation time should be very limited, especially if the fetus is still alive or if the female shows signs of extreme distress. Therefore, decision-making and preparation of the animal should be fast to guarantee the safety of the dam and fetus.

Restraint and preparation of the surgical site

For the flank approach, the animal is placed in a right lateral recumbency. Dorsal recumbency is required for the ventral midline approach.^{(4, 8)} The animal can be tranquilized as soon as the decision to operate is made. For the midline approach, a 20-cm-wide area from the base of the udder to the umbilic is clipped or shaved. For the flank approach, the site to be clipped should cover the entire flank from the lumbar vertebrae.

Anesthesia

General anesthesia is required for all laparotomies in the llama and alpaca. Several anesthetic regimes have been described for the llama and alpaca. The most commonly used technique consists of an induction by administration of 10% solution of guaifenesin (350 ml) followed by a maintenance regime of spontaneous ventilation with 2% halothane and oxygen (6 1/min) in a semi-closed circuit.⁽⁸⁾ This anesthesia regimen has a major advantage which is that both drugs (guaifenesin and halothane) have minimal effect on the fetus and neonate.⁽⁸⁾

Surgical procedure for the ventral midline approach

1)    Incision of the skin and underlying tissues: A 30 to 40 cm incision is made through the skin beginning at the cranial border of the udder. The tissue layers penetrated are: the skin, subcutaneous areolar tissue, cutaneous trunci muscle, superficial fascia (aponeuroses of the external and internal abdominal oblique muscles), deep fascia (the thin aponeurosis of the transversus abdominis muscle), retroperitoneal fat, and the peritoneum. The incision must be made directly on the linea alba to avoid cutting the rectus abdominis muscles.^{(4, 8, 18)}

2)    Exteriorization of the uterus: The uterine horn is exteriorized by grasping it at the level of a fetal limb and gently pulling it toward the surgical opening. Exteriorization of the uterus using this approach may be difficult in the case of uterine torsion or the presence of an unusually large fetus. Extreme caution should be exercised when pulling on the uterus so as not to produce uterine tears especially if the organ is already fragile due to a long-standing affection.

3)    Uterine incision and exteriorization of the fetus: As is the rule for all species, the incision is made on the greater curvature of the uterus to avoid large blood vessels which run in the broad ligament and toward the small curvature. Uterine incision should be large enough (20 to 30 cm) to allow passage of the fetus without the risk of tearing.⁽⁸⁾ The fetus is pulled out of the uterine cavity by an aide holding both exteriorized limbs. If the fetus is in anterior presentation, the posterior limbs will be exteriorized first. Care should be taken not to rupture the umbilical cord before clamping it. When the fetus is in posterior presentation, the anterior limbs are exteriorized first. In this case, the operator should make sure that the head is straight and exteriorized before proceeding to pull the fetus any further. The head of the fetus should be exteriorized quickly to avoid inhalation of the amniotic fluid. The area of largest diameter (chest of the fetus) should be handled with care and exteriorized slowly in order to avoid uterine tears.' Once the fetus is completely removed from the uterine cavity, the umbilical cord is ligated before proceeding to separation of the placenta. Manual removal of the placenta before closing the uterus is possible because of the diffuse, microcotyledonary type of placenta in camelidae which makes it easy to be "peeled off" from the uterine wall. If the chorion is still firmly adhered it should be left in place.

4)    Suture of the uterus: If the placenta has not been totally removed, it should be manually separated from the endometrium for a distance of 5 cm from the edges of the surgical wound. This will allow a better apposition of the uterine incision borders. The uterus is closed using a two-layer Lembert infolding suture pattern with absorbable suture material (chromic gut No. 1). The uterine surface is cleaned with physiological saline solution and inspected for the presence of tears before being replaced into the abdominal cavity.

5)   Suture of the abdominal cavity: The abdominal cavity should be flushed with physiological saline and cleaned of any blood before proceeding to the closure of the peritoneum. The peritoneum is closed with a continuous mattress suture or interrupted horizontal mattress using an absorbable suture material (catgut 0).⁽⁸⁾ The subcutaneous layer is closed by a continuous pattern with chromic gut No. 1.⁽⁸⁾ This is followed by closure of each muscular layer with continuous mattress.suture. The skin incision can be sutured or stapled.⁽⁸⁾

6)    Post-surgical care: Post-surgical care focuses on prevention of infectious complications after surgery and prevention of other postpartum complications such as septic metritis and retained placenta. Administration of oxytocin (30 to 40 IU, IV) is recommended if manual removal of the placenta is not possible. In addition to promoting placenta delivery, the contracting effect of oxytocin on the smooth muscle of the uterus and uterine blood vessels causes a vasoconstriction which prevents excessive bleeding from the surgical site. Oxytocin should not be administered until the uterus has been sutured and replaced within the abdomen. Oxytocin can also help with milk let down. If this treatment does not resolve agalactia, the newborn should receive colostrum from another female within a few hours of birth to insure passive transfer of immunity.

Prevention of infection is accomplished by a 5-day course of systemic antibiotic (4 mg sulfadiazine and 8 mg trimethoprim IV daily for five days).⁽⁸⁾ Uterine boluses are contraindicated because they may cause straining and risk of uterine prolapse. Non-steroidal anti-inflammatory drugs (flunixin meglumine 200 mg IV) are usually administered to reduce inflammation.⁽⁸⁾ In addition to this treatment, anti-tetanus prophylactic measures are recommended by some practitioners, in the form of a booster for vaccinated animals or administration of anti-tetanus serum in non-vaccinated animals. Skin staples or sutures can be removed 10 days after surgery. Involution of the uterus should be monitored regularly. The decision to proceed with rebreeding is based on the evolution of the involution and surgical site.

Surgical procedure for the flank (Paralumbar) approach

The left side is a better choice for flank cesarean section because it gives easy access to the pregnant horn (which is the left horn in nearly 100% of the cases).

1)    Incision of the skin and underlying tissue layers: The abdominal wall over the flank region is composed of several layers of tissue - the skin, the first muscle layer (external abdominal oblique muscle), the second muscle layer (internal abdominal oblique muscle), the third muscle layer (transverse abdominal muscle), and the peritoneum. The skin is incised vertically, midway between the tuber coxae and the last rib, 6 to 8 cm ventral to the transverse processes of the lumbar vertebrae. The external abdominal oblique muscle is incised but the internal oblique and transverse muscles are dilacerated following the direction of their fibers. The retroperitoneal fat layer is dissected to expose the peritoneum. The peritoneum is held with a thumb forceps and punctured with scissors then opened using a finger to guide the scissors and avoid internal organs.

2)    Exteriorization of the uterus: The uterus is exteriorized and incised in the same manner described for the ventral midline approach.

3)    Suture of the abdominal wall: The peritoneum is closed with either a continuous or simple interrupted pattern using synthetic absorbable suture material. The muscle layers are sutured separately using a simple interrupted
suture. The skin is sutured or closed with staples.

4)   Post-surgical care: identical to that for the ventral midline approach.

Cesarean section in the dromedary and Bactrian camel

Cesarean section in Camelus dromedarius and Camelus bactrianus is made through a flank or ventrolateral approach. Restraint of the animal will depend on the selected site. The low ventrolateral approach requires restraining the female in a right lateral recumbency,^{(2, 15)} whereas flank approach can be done on the female sitting in the normal sternal position (Figure 9.1).^{(7, 9)} Each technique has its advantages and disadvantages. The practitioners will tend to select the technique they are most familiar with.

Preoperative preparation and anesthesia

Cesarean section has been accomplished under many different anesthetic treatments in the dromedary female. These include chloral hydrate^{(10, 13)} premedication with chlorpromazine hydrochloride followed by a chloral hydrate and magnesium sulphate mixture⁽¹⁵⁾ premedication with blood diluted trifluopromazine⁽⁹⁾ sedation with 6 ml of 5% solution of xylazine (50 mg /ml) administered by slow intravenous injection followed by local anesthesia,⁽¹⁴⁾ sedation with xylazine 2% (3 ml) plus epidural anesthesia with local infiltration, and intramuscular injection of uterus relaxant ⁽⁵⁾ or local anesthesia alone.⁽⁷⁾ Selection of the anesthetic regime depends on the viability of the fetus and the degree of depression of the female. We use a regional anesthesia of the surgical site by inverted L and line block (30 ml of 2% lidocaine solution) associated with good restraint of the animal. The animal is sedated with xylazine hydrochloride after exteriorization of the fetus to complete the last stages of the surgery. Administration of xylazine is not recommended if the animal is depressed.

A wide (30 x 30 cm) area around the selected surgical site is shaved and scrubbed thoroughly (Figure 9.2). If the operation is done in the field the surrounding sand should be covered with plastic or wetted to avoid its introduction into the surgical site. Risks of sand contamination can also be reduced by operating under a make-shift tent.
 

Cesarean section by left ventrolateral approach

1)    Incision of the skin and underlying tissues: A 30- to 45-cm skin incision is made 5 to 10 cm above and parallel to the subcutaneous abdominal vein in an oblique fashion.^{(2, 14)} The incision is made through the skin, subcutaneous tissue, tunica flava abdominis, rectus abdominis muscle, and peritoneum. The greater omentum is retracted cranially before exteriorization of the uterine horn.^{(2, 14)}

2)    Exteriorization and incision of the uterus: The ventral portion of the gravid horn is exteriorized and a 35-cm incision is made along the greater curvature. In the case of uterine torsion, the fetus must be delivered before attempting correction of the torsion.⁽²⁾ The fetus is delivered in the same manner described for the llama.

3)    Suture of the uterus and abdominal wall: The uterine incision is closed after removal of the placenta if possible, using a row of cushing sutures superimposed with continuous Lembert (chromic catgut No. 2 or 3).^{(2, 14)} The uterus is then lavaged with sterile saline, cleaned of blood clots, and replaced inside the abdominal cavity. The peritoneum, muscular layers, and subcutaneous tissue are closed separately with simple continuous sutures using chromic gut No. 2.⁽²⁾ Others prefer suturing the peritoneum and the internal oblique muscles in one layer and the external oblique in another using continuous sutures. The skin incision is stapled or closed by interrupted mattress sutures using silk No. 4.⁽¹⁶⁾

After delivery, either chlortetracycline pessaries are placed in the uterus by some authors⁽²⁾ or antibiotic powder is used.^{(14, 15)} We prefer to administer antibiotics systemically.

Cesarean section via paralumbar fossa approach

Two techniques are usually used for this approach: incision in the left paralumbar fossa about 6 cm below the second lumbar transverse process and parallel to the last rib extending through skin muscles and peritoneum,⁽¹⁵⁾ or an oblique incision made in the lower flank 10 cm posterior to the last rib.⁽⁹⁾ The technique we prefer is close to the low flank incision (Figure 9.3). A 35- to 40-cm skin incision is made starting 10 cm from the angle formed by the hip and the lumbar vertebrae and continued downwards parallel to the thighs in the sitting animal. The first muscular layer (external abdominal oblique muscle) is incised followed by a grid separation of the second and third abdominal muscles (internal abdominal oblique muscle and the transverse abdominal muscle) (Figure 9.3). The retroperitoneal adipose tissue is grasped with tissue forceps and pulled towards the surgical site. A small incision is made with blunt dissecting scissors to uncover the peritoneum. Incision of the peritoneum is made along the surgical site with blunt dissecting scissors, making sure not to cut any intestinal loops (Figure 9.3). The uterus is exteriorized by grasping the left uterine horn at the level of one of the fetal limbs (Figure 9.4). A 35- to 40-cm incision is made along the large curvature of the left uterine horn and the fetus is delivered by gentle traction (Figure 9.4). The uterus and different layers of the abdominal wall are closed in the same manner as described above (Figure 9.5 and 9.6). In the case of uterine torsion, the position of the organ should be corrected and the whole surface of the uterine wall checked for ruptures or other lesions.

Post-operative care includes administration of 30 to 40 IU of oxytocin IM to stimulate uterine contraction and expulsion of the placenta or lochia. Antibiotherapy should be continued for 5 to 10 days. Sutures can be removed two weeks after surgery.

Complications following cesarean section in the dromedary include: retained placenta, metritis, endometritis, agalactia, eventration, or herniation of the surgical site.⁽¹¹⁾ Eventration occurs during the period following the operation but herniation usually appears during the middle of the subsequent pregnancy. Severe infestation of the surgical wound by fly larvae, dehiscence, and abscesses are frequently seen in cases done in the field.
 

References

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