Pediatric Surgery: Hypertrophic Pyloric Stenosis

Hypertrophic Pyloric Stenosis

Risk Factors

  • Males
  • First-Born Infants with a Positive Family History
  • Breast-Feeding (Vs Formula Feeding)
  • Erythromycin (Often Given as Pertussis Prophylaxis)
  • Transpyloric Feeding of Premature Infants

Presentation

Diagnosis

  • Can Be Made by History & Physical Exam with Olive-Shaped Mass
  • Gold Standard: US
    • If US Findings are Borderline Wait A Few Days & Repeat US – Pyloric Stenosis Will Continue to Progress
  • US Findings: Mn
    • Pyloric Muscle Thickness (PMT) ≥ 3-4 mm
    • Pyloric Muscle Length (PML) > 14-19 mm
    • Pyloric Diameter (PD) > 14 mm

Treatment

  • Initial Management: Resuscitation #1
    • Dehydration:
      • Initial Bolus: NS, Until Making Urine
      • Maintenance: D5 ½ NS + 20 KCl
        • Peds at Risk for High K & Low Na/Glucose
        • Rate 1.5-2.0x Normal
    • Correct Electrolyte Disturbances
    • Avoid Routine Nasogastric Tube Placement – Can Worsen Electrolyte & Acid-Base Imbalance
  • Definitive Treatment: Ramstedt Pyloromyotomy

Pyloric Stenosis on US; 20 mm Length (a), 5 mm Thick (b) 1

Ramstedt Pyloromyotomy

Procedure

  • Abdominal Access Technique:
    • Minimal Laparotomy (Open) – 2.5-3.0 cm Transverse RUQ Incision
    • Laparoscopic
  • Anterior Longitudinal Incision of Pylorus Muscle
    • Extent:
      • Proximal Extent: Just Before the Hypertrophied Muscle onto Antrum of Stomach
      • Distal Extent: Just Proximal to Pyloric Vein
        • Appropriate to Leave a Few Muscle Fibers Intact at the Distal End to Prevent Duodenal Perforation
    • Submucosa Bulges Through Incision
    • If Enter the Lumen: Close & Preform a Posterior Pyloromyotomy
  • Defect is Left Open
  • Close Fascia & Skin

Complications

  • Postoperative Emesis
    • < 1 Week: Expected
      • Causes:
        • GERD
        • Discordant Peristalsis
        • Atony
        • Poor Emptying
      • Tx: Continue Feeding
    • > 1 Week: Concern for Incomplete Myotomy
      • Consider Reexploration
  • Incomplete Myotomy
    • Most Common Cause: Fail to Extend Far Enough Proximally onto Antrum
    • Contrast Study Not Helpful (Several Weeks for Appearance to Improve)
  • Bowel Perforation/Leak

Pyloromyotomy; (a) Muscle Hypertrophy, (b-c) Muscle Separation, (d) Completed Myotomy 2

Mnemonics

US Findings in Pyloric Stenosis

  • “Pi”-loric – Pi = 3.14
    • 3 mm Thick
    • 14 mm Length/Diameter

References

  1. Rhee Y, Heaton T, Keegan C, Ahmad A. Citrullinemia type I and hypertrophic pyloric stenosis in a 1-month old male infant. Clin Pract. 2013 Jan 25;3(1):e2. (License: CC BY-NC-3.0)
  2. Parelkar SV, Oak SN, Bachani MK, Sanghvi BV, Gupta R, Prakash A, Patil R, Sahoo S. Minimal access surgery in newborns and small infants; five years experience. J Minim Access Surg. 2013 Jan;9(1):19-24. (License: CC BY-NC-SA-3.0)