Overview
Definition:
Laparoscopic pyloromyotomy is a minimally invasive surgical procedure to relieve the obstruction caused by hypertrophied pyloric muscles in infantile hypertrophic pyloric stenosis (IHPS)
It involves incising the thickened muscle layers of the pylorus, allowing gastric contents to pass into the duodenum.
Epidemiology:
IHPS is a common cause of non-bilious vomiting in infants, typically presenting between 2-8 weeks of life
The incidence is estimated to be 1-3 per 1000 live births
It is more common in first-born males and infants with a family history of the condition
Certain genetic factors and prenatal exposures are implicated.
Clinical Significance:
IHPS leads to significant dehydration, electrolyte imbalances (especially hypochloremic metabolic alkalosis), malnutrition, and failure to thrive if not treated promptly
Accurate diagnosis and timely surgical intervention are crucial for favorable outcomes and preventing severe complications
Laparoscopic approach offers reduced morbidity and faster recovery.
Clinical Presentation
Symptoms:
Projectile, non-bilious vomiting, typically starting after 2-3 weeks of age
Emesis may be forceful and occur immediately after feeding or shortly thereafter
Persistent hunger despite vomiting
Weight loss or failure to gain weight appropriately
Constipation may be present due to reduced intestinal transit
Jaundice is uncommon but can occur in severe cases.
Signs:
Palpable "olive-shaped" mass in the epigastrium, typically on the right side, after vomiting
Gastric peristaltic waves visible across the abdomen, moving from left to right
Dehydration signs include dry mucous membranes, decreased skin turgor, sunken fontanelle, and oliguria
Bradycardia and lethargy can indicate severe dehydration.
Diagnostic Criteria:
Clinical suspicion based on characteristic vomiting pattern and physical findings
Definitive diagnosis is made by imaging, primarily ultrasound, which shows an elongated, thickened pylorus with a narrow lumen
A muscle thickness of >4 mm and a canal length of >16 mm are indicative of IHPS
Upper GI contrast study can also be used, showing a "string sign" or "beak sign" at the pylorus.
Diagnostic Approach
History Taking:
Detailed history of feeding patterns and emesis characteristics is paramount
Onset, frequency, volume, and projectile nature of vomiting
Bilious or non-bilious
Associated symptoms like fever, diarrhea, or abdominal distension
Birth history and any family history of GI anomalies or IHPS
Recent weight changes and hydration status.
Physical Examination:
Thorough assessment for dehydration, including mucous membranes, skin turgor, fontanelle, and vital signs
Careful palpation of the abdomen, especially the epigastrium, for a pyloric "olive"
Observation for gastric peristaltic waves
Rule out other causes of vomiting in infants.
Investigations:
Abdominal ultrasound: The investigation of choice, demonstrating pyloric muscle thickness (>4mm) and length (>16mm)
Upper GI contrast study: Can show a narrowed pyloric channel, string sign, or beak sign
Complete blood count (CBC) to assess for anemia or infection
Electrolyte panel: Crucial for assessing hydration status and identifying hypochloremic metabolic alkalosis (low chloride, normal to low potassium, elevated bicarbonate)
Blood urea nitrogen (BUN) and creatinine to assess renal function.
Differential Diagnosis:
Gastroesophageal reflux disease (GERD): Usually benign regurgitation, not projectile vomiting
Pylorospasm: Transient, resolves spontaneously
Intestinal obstruction (e.g., malrotation with volvulus, duodenal atresia): Often associated with bilious vomiting and abdominal distension
Gastritis or gastroenteritis: Typically accompanied by diarrhea and fever
Neurological causes: Rare, usually associated with other neurological signs.
Management
Initial Management:
Fluid resuscitation: Aggressive intravenous fluid administration to correct dehydration and electrolyte imbalances
Nasogastric (NG) tube insertion for gastric decompression and to reduce further emesis
Correction of electrolyte abnormalities, particularly hypochloremic metabolic alkalosis, with intravenous fluids containing chloride and potassium as indicated.
Medical Management:
Primarily supportive care and correction of fluid and electrolyte deficits
No specific medical cure for IHPS
Antiemetics are generally not recommended as they do not address the underlying obstruction and can mask the severity of vomiting
Once electrolytes are corrected and patient is stable, surgical intervention is planned.
Surgical Management:
Laparoscopic Ramstedt-Fredet pyloromyotomy: The gold standard surgical treatment
Incision made through the serosa and muscularis propria of the pylorus, sparing the mucosa
Typically involves 3 small umbilical port sites
Advantages include reduced postoperative pain, shorter hospital stay, faster return to oral feeding, and smaller scars compared to open surgery
Open pyloromyotomy is an alternative if laparoscopic surgery is not feasible.
Postoperative Care:
Pain management with analgesics
Gradual reintroduction of oral feeds, starting with clear liquids (e.g., glucose water) and progressing to formula or breast milk as tolerated
Monitoring for signs of wound infection or complications
Early ambulation
Discharge typically within 24-48 hours if tolerating feeds and no complications.
Complications
Early Complications:
Incomplete pyloric division: Persistent vomiting post-operatively, requiring re-operation
Mucosal perforation: Can occur during myotomy, necessitating repair and potentially conversion to open surgery
Bleeding: From the muscle incision
Wound infection: At port sites
Bowel injury: Rare, due to trocar insertion or dissection
Pneumoperitoneum related complications.
Late Complications:
Adhesions: Can lead to bowel obstruction, although less common with laparoscopic surgery
Wound hernia: At port sites
Chronic gastric stasis: Rare, may require further investigation
Psychological impact of scarring (minor with laparoscopic approach).
Prevention Strategies:
Careful dissection and identification of the pyloric muscle layers to avoid mucosal injury
Meticulous hemostasis
Proper port placement to minimize risk of bowel injury
Postoperative vigilance for recurrent or persistent vomiting which may indicate incomplete myotomy
Standard sterile surgical techniques to prevent wound infections.
Prognosis
Factors Affecting Prognosis:
Severity of preoperative dehydration and electrolyte imbalance
Promptness of diagnosis and surgical intervention
Surgical technique and experience of the surgeon
Presence of associated congenital anomalies
Postoperative complications.
Outcomes:
Excellent with prompt diagnosis and treatment
Most infants recover fully and resume normal feeding and growth
Recurrence of IHPS is extremely rare
Laparoscopic pyloromyotomy has a high success rate with minimal morbidity
Long-term outcomes are generally very good.
Follow Up:
Routine follow-up is usually not required unless there are specific concerns
Parents are educated on normal postoperative recovery and when to seek medical attention
Monitoring for weight gain and resolution of vomiting symptoms
Most infants can be discharged home within 1-2 days post-surgery.
Key Points
Exam Focus:
IHPS is characterized by projectile, non-bilious vomiting in infants aged 2-8 weeks
Palpable pyloric "olive" and visible peristalsis are key signs
Ultrasound is diagnostic, showing thickened pyloric muscle and narrow lumen
Laparoscopic pyloromyotomy is the definitive surgical treatment
Hypochloremic metabolic alkalosis is a common electrolyte disturbance.
Clinical Pearls:
Always consider IHPS in an infant with unexplained projectile vomiting
Differentiate from GERD by the forcefulness and projectile nature of vomiting
The "olive" is best felt after the infant has vomited
Aggressive fluid resuscitation is crucial before surgery
Start oral feeds early postoperatively to promote gut function.
Common Mistakes:
Delaying diagnosis due to attributing symptoms to reflux or overfeeding
Inadequate correction of electrolyte imbalances preoperatively
Performing incomplete pyloromyotomy leading to persistent vomiting
Not performing meticulous hemostasis during surgery
Overlooking associated congenital anomalies.