Chapter 46. Operative Management of Pyloric Stenosis: Pyloromyotomy

• Projectile nonbilious emesis in an infant.
• Palpable "olive" on physical examination.
• "String sign" on an upper gastrointestinal series.
• Pyloric muscle wall thickness ≥ 4 mm and pyloric channel length ≥ 16 mm on ultrasound examination.

• Severe hypochloremic, hypokalemic metabolic alkalosis.
• Severe dehydration.

• The procedure is successful in nearly 100% of cases.

Expected Benefits

• Elimination of the mechanical gastric outlet obstruction caused by a hypertrophic pylorus.

Potential Risks

• Incomplete myotomy (usually gastric).
• Mucosal perforation (usually duodenal).
• Wound infection.
• Postoperative bleeding.
• Fascial dehiscence.

• Open pyloromyotomy: pyloric spreader (Benson).
• Laparoscopic pyloromyotomy.
  • Veress needle and sheath.
  • 5-mm umbilical port.
  • 3-mm instruments, including laparoscopic pyloric spreader.

• Pyloric stenosis is not a surgical emergency; the goal of preoperative evaluation is to confirm the diagnosis and to correct metabolic derangements caused by persistent vomiting.
• Diagnosis is based on a thorough history and physical examination and is usually confirmed by radiographic findings.
  • A history of projectile nonbilious vomiting between ages 4 and 6 weeks and a palpable "olive" is sufficient for diagnosis.
  • If the diagnosis is unclear, ultrasound examination of the pylorus is the radiologic procedure of choice.
• Criteria for ultrasound diagnosis are pyloric muscle wall thickness ≥ 4 mm and pyloric channel length ≥ 16 mm.
• Once the diagnosis is suspected, the patient should not ingest anything orally.
• Preoperative nasogastric decompression is not required and may exacerbate the metabolic alkalosis.
• The most common metabolic abnormality is hypochloremic, hypokalemic metabolic alkalosis (HCO3 ≥ 30 mEq/L) and overall volume deficit.
• The patient should be rehydrated with 20 mL/kg boluses of normal saline until urinating and then given D5½ normal saline (10–20 mEq KCl/L if indicated) at a maintenance rate of 1.5. Lactated Ringer solution is contraindicated because it may exacerbate the metabolic alkalosis.

• Figure 46–1A: For both open and laparoscopic procedures, the infant should be supine on the operating table.
• Laparoscopic procedure.
  • The infant is positioned supine at the end of the operating table with appropriate padding.
  • The lower extremities are secured to the operating table in a frog leg position.

• Before induction of anesthesia, nasogastric decompression should be performed.
• Figure 46–1B: A longitudinal incision is made in the umbilicus and a Veress needle and trocar sheath are inserted.
  • A CO2 pneumoperitoneum is established to a level of 10–12 mm Hg, and a 5-mm port is inserted.
  • Under direct vision, a No. 11 blade is used to make two 3-mm stab incisions in the upper abdominal wall.
• Figure 46–1C: An open pyloromyotomy is performed using a right upper quadrant or umbilical skin incision.
  • Right upper quadrant incision: a transverse incision is made directly over the right rectus muscle midway between the xiphoid and umbilicus. The rectus muscle may be divided transversely or ...