Overview
Definition:
Pyloromyotomy, specifically the Ramstedt procedure, is the surgical division of the hypertrophied pyloric muscle in infantile hypertrophic pyloric stenosis (IHPS) to relieve gastric outlet obstruction.
Epidemiology:
IHPS affects approximately 2-5 per 1000 live births in Western populations, with higher incidence in males (4:1 ratio) and first-born infants
prematurity and certain genetic factors are associated
It is a common cause of non-bilious vomiting in infancy.
Clinical Significance:
IHPS is a common surgical emergency in neonates and infants, requiring prompt diagnosis and surgical intervention to prevent dehydration, malnutrition, and electrolyte imbalances
Understanding the Ramstedt procedure is crucial for surgical residents preparing for board examinations.
Clinical Presentation
Symptoms:
Progressive non-bilious, projectile vomiting, often starting at 2-8 weeks of age
Persistent hunger despite vomiting
Decreased urine output and infrequent stools
Dehydration signs: sunken fontanelle, dry mucous membranes, poor skin turgor
Weight loss or failure to gain weight.
Signs:
Palpable "olive" mass in the epigastrium (highly suggestive, found in 60-80% of cases)
Visible gastric peristaltic waves moving from left to right across the upper abdomen
Abdominal distension can occur late.
Diagnostic Criteria:
Clinical suspicion confirmed by imaging
The classic presentation of projectile non-bilious vomiting in an infant of appropriate age with palpable olive is often sufficient for diagnosis, but imaging is used to confirm and rule out other causes.
Diagnostic Approach
History Taking:
Detailed history of vomiting: timing, character (non-bilious vs
bilious), projectile nature, frequency, amount
Onset of symptoms
Feeding history and weight gain pattern
Hydration status and urine output
Family history of IHPS
Red flags: bilious vomiting (suggests intestinal obstruction beyond pylorus), lethargy, fever (suggests sepsis).
Physical Examination:
Assess hydration status (mucous membranes, skin turgor, fontanelle)
Palpate the abdomen carefully for a gastric peristaltic wave and the pyloric "olive" mass in the epigastrium
Auscultate bowel sounds
Check for signs of other congenital anomalies.
Investigations:
Abdominal ultrasound is the investigation of choice: measures pyloric muscle thickness (>3 mm) and length (>15 mm), and shows a "string sign" or "target sign" of the pylorus
Upper GI series can also be diagnostic but is less preferred due to radiation exposure
Laboratory tests are essential to assess electrolyte status and hydration: serum electrolytes (sodium, potassium, chloride, bicarbonate), BUN, creatinine, blood glucose.
Differential Diagnosis:
Gastroesophageal reflux (GER) and GER disease (GERD), milk allergy/intolerance, other causes of infant vomiting (e.g., sepsis, meningitis, intestinal malrotation, intussusception, intra-abdominal mass), hypertrophic pyloric stenosis without palpable olive.
Management
Initial Management:
Immediate resuscitation is critical
Intravenous (IV) fluids to correct dehydration and electrolyte imbalances, particularly hypochloremic metabolic alkalosis
Nasogastric tube (NGT) decompression for gastric emptying
Correct electrolyte abnormalities (e.g., chloride replacement).
Medical Management:
Primarily supportive and preparatory for surgery
IV fluids and electrolyte correction are the cornerstone
Antiemetics are generally not used as they can mask symptoms and do not address the underlying obstruction.
Surgical Management:
The definitive treatment is pyloromyotomy
Indications include confirmed IHPS with persistent vomiting and dehydration not adequately corrected by medical management, or failure to thrive
The Ramstedt procedure involves a longitudinal myotomy through the hypertrophied pyloric muscle, sparing the mucosa, allowing the circular muscle fibers to separate and relieve the obstruction
Can be performed open or laparoscopically.
Supportive Care:
Continuous monitoring of vital signs, fluid balance (intake and output), and electrolytes
Post-operative care includes gradual reintroduction of oral feeds, pain management, and monitoring for complications
Parental reassurance and education are vital.
Complications
Early Complications:
Incomplete myotomy (persistent vomiting, requiring re-operation)
Perforation of the gastric or duodenal mucosa (rare, potentially leading to peritonitis or leak)
Bleeding from the incision
Wound infection
Sepsis
Intra-abdominal abscess.
Late Complications:
Retained gastric fluid or food material
Pyloric stenosis recurrence (very rare)
Adhesions
Gastric emptying abnormalities (delayed emptying).
Prevention Strategies:
Meticulous surgical technique by experienced surgeons to ensure complete muscle division without mucosal injury
Adequate pre-operative resuscitation
Careful post-operative feeding advancement
Good surgical asepsis to prevent wound infections.
Prognosis
Factors Affecting Prognosis:
Severity of pre-operative dehydration and malnutrition
Skill of the surgical team
Presence of any associated congenital anomalies
Timeliness of diagnosis and intervention.
Outcomes:
Excellent with prompt diagnosis and surgical treatment
Most infants resume normal feeding within 24-48 hours post-operatively and are discharged within 2-3 days
Long-term outcomes are generally very good with minimal sequelae.
Follow Up:
Typically, a short follow-up with the surgeon is recommended to ensure complete recovery and adequate weight gain
Long-term follow-up is usually not required unless specific complications arise.
Key Points
Exam Focus:
The Ramstedt procedure is the gold standard for IHPS
Classic presentation: projectile non-bilious vomiting at 2-8 weeks, palpable olive
Ultrasound is diagnostic
Management is surgical
Complications include incomplete myotomy and mucosal injury.
Clinical Pearls:
Always palpate for the gastric peristaltic wave and the "olive"
Dehydration and metabolic alkalosis are key pre-operative considerations
Laparoscopic pyloromyotomy offers faster recovery and less scarring.
Common Mistakes:
Mistaking IHPS for simple reflux
Delaying surgery due to misdiagnosis
Inadequate pre-operative resuscitation
Incomplete or too extensive myotomy
Not considering other causes of vomiting in infants.