Caesarean section

• Surgical management of dystocia Dystocia.

• Prolonged gestation.
• Primary uterine inertia - inability of uterus to contract sufficiently (some breed predisposition, eg Boxer Boxer ).
• Secondary uterine inertia, uterine muscles become exhausted after prolonged contraction (obstructing fetus, large litter, some breed predisposition, eg brachycephalics).
• Unmanageable obstruction of birth canal, eg pelvic fracture.
• Uterine anomaly, eg torsion, inguinal herniation of gravid uterus.

• Relative or absolute fetal oversize.
• Irreduceable malpresentation.
• Fetal death/putrefaction/mummification.
• Signs of fetal distress in prolonged or difficult parturition.
• Fetal deformity, eg fetal monster.

• History of previous dystocia.
• Predictable dystocia associated with breed type especially brachycephalics.

Advantages

• Increased chance of live pups following rapid removal of viable fetuses.

Disadvantages

• Anesthetic depression of fetus.
• Care required to prevent fetal hypoxia.
• Cost.
• Risk of surgical complications in dam (low).

• Consider medical management prior to surgery if no obvious fetal anomalies or pelvic obstruction. (Oxytocin Oxytocin for non-obstructive dystocia with dilated cervix.)
• Calcium gluconate Calcium gluconate for, eg primary uterine inertia due to subclinical hypoglycemia.

• If reduceable malpresentations.
• If marginal fetal oversize without uterine inertia.
• If dead fetus obstructing canal.

Preparation

• Pre-operative blood tests to screen for hypoglycemia, hypocalcemia, anemia.
• Supplementation with glucose and calcium as needed.
• Clip hair 10 min prior to induction of anesthesia.

Procedure

• 30-60 min.
• Procedure should be performed as quickly as possible.

Criteria for choosing test

• Objective evaluation of indications for surgical intervention not always possible.
• Length of gestation shows great variation within normal (54-72 days).
• Often difficult to assess cause of dystocia.
• Considerable range in normal interval between expulsion of pups (5 min-2 h).
• Digital examination of the vagina may detect a fetus lodged in the birth canal. Check for the presence of the Ferguson reflex (ie digital pressure on the ventral or dorsal vaginal wall results in abdominal straining). No reflex suggests that the dog is not in labor or that uterine inertia is present.
• Decision often a subjective assessment of behavioral signs and experience.

• Prolonged gestation greater than 65 days.
• Persistent abdominal straining more than 30 min without expulsion of puppy.
• Weak and infrequent abdominal straining which fail to produce puppy within 2-3 hours.
• Absence of abdominal straining for longer than 4 hours between births.
• Physical examination, eg pelvic obstruction.
• Signs of systemic illness, eg toxemia, fever, depression, weakness.
• Evidence of fetal death.
• Abnormal vulval discharge.

Anesthetist expertise

• Experienced anesthetist:
  • See: Anesthesia for Cesarean section Anesthesia: for Cesarean section for preparation and general anesthesia considerations.
• As many personnel as posible to manage neonates.

Minimum equipment

• Standard laparotomy kit Surgical instruments.

Ideal equipment

• Sterile laparotomy swabs for packing of uterus.
• Equilment for puppy resuscitation, eg suction, medications including adrenaline and doxapram Doxapram.
• Incubator.
• Towels/blankets for neonates.

• Fast animal for 12 hours prior to anesthetic to prevent reflux esophagitis (if able - may need to be performed as an emergency.)

• Ventral midline approach: tilting bitch in dorsal recumbency relieves respiratory embarassment, alleviates caval occlusion, gives best access to gravid uterus.
• Flankapproach: avoids damage to mammary vessels and post-operative wound interference by young.

Standard Method

• Standard laparotomy Laparotomy: midline 

• Intravenous fluids if prolonged dystocia.

Step 1 - Ventral midline laparotomy

• Optional - in most animals (<30 kg) this is unnecessary.
• Incise skin .
• Make laparotomy exposure large enough only for uterine access .

Step 1 - Inspect and exteriorize uterus

• Inspect uterus for signs of rupture or fetal death .
• May elect for ovariohysterectomy Ovariohysterectomy with client consent.
• Carefully exteriorize.
  Sudden exteriorization may result in transient fall in blood pressure.
• Pack off uterus from abdominal cavity with warm moist towels .

Step 2 - Incise uterus and removal of young

• Make longitudinal incision at uterine bifurcation .
• 'Milk out' pups through single incision  .
• Perforate fetal membranes.
• Clamp umbilicus before sectioning .
• Keep all pups warm and monitor carefully  .
  Ensure all pups removed, especially first dystocic pup.

Step 3 - Inspect placenta

• Presence of placenta with pup often indicates fetal death.
• Remove placenta if free; leave if still tightly attached.

Step 4 - Alternative technique - en bloc ovariohysterectomy

• Exteriorize uterus.
• Isolate ovarian pedicles and body of uterus.
• Milk fetuses into uterine body.
• Double or triple clamp pedicles and uterus cranial to cervix.
• Transect between clamps and give uterus to team of assistants for resuscitation of fetuses.
• Ligate pedicles of uterus and close.

Step 1 - Standard laparotomy closure

• Same as laparotomy Laparotomy: midline .
  Cuticular or silk sutures may minimize pup-initiated wound complications.

Step 2 - Uterine closure

• Suture (absorbable sutures) using inverting or appositional pattern  .
  No real rationale for double layer of sutures.
• Single and double layer closures have been recommended.

Fluid requirements

• Intravenous fluids if prolonged dystocia.

General Care

• Pass each puppy to assistant to be towel-dried.
• Massage puppy to promote respiration. Doxapram Doxapram can be used to stimulate respiration 1-2 drops.
• Suck fluids from fetal airways.
• Maintain in warm dry environment, eg incubator. Naxolone Naloxone can be given to neonates to reverse narcotics given to bitch pre-operatively.
  Sucking may be delayed for up to 6 hours post-partum without detriment.
• Return puppies to bitch on recovery.

Other medication

• Oxytocin Oxytocin may help control hemorrhage.

Wound Protection

• No wound protection required - use subcuticular sutures.

Potential complications

• Hemorrhage, hypovolemia, hypotension, peritonitis Peritonitis if leakage of uterine fluids intra-operatively.

• Diarrhea: not uncommon, hormonally-mediated or from eating placenta(e).

• Good.

• Delay in procedure or prolonged procedure that results in death of viable fetus.

Refereed papers

• Recent references from PubMed and VetMedResource.
• Metcalfe S, Hulands-Nave A, Bell M et al (2014) Multicentre, randomised clinical trial evaluating the efficacy and safety of alfaxalone administered to bitches for induction of anaesthesia prior to caesarean section. Aust Vet J 92 (9), 333-338 PubMed.
• Smith F O (2012) Guide to emergency interception during parturition in the dog and cat. Vet Clin North Am Small Anim Pract 42 (3), 489-499 PubMed.
• Evans K M & Adams V J (2010) Proportion of purebred dogs born by caesarean section. JSAP 51 (2), 113-118 PubMed.