Pyloromyotomy

Chapter 87 Pyloromyotomy



Aziz Merchant, MD, Kurt D. Newman, MD



INTRODUCTION


Infantile hypertrophic pyloric stenosis (HPS) is a common condition of infancy that is easily corrected by surgery. The overall annual incidence ranges from 8.2 to 12.3 cases per 1000 live births.1 The classic presentation is that of nonbilious, projectile vomiting in a 2- to 8-week-old newborn. The vomiting results in a contraction alkalosis secondary to severe dehydration. Sonographic identification of a thickened and lengthened pylorus helps to solidify the diagnosis. The “gold standard” of treatment is the open pyloromyotomy described by Fredet in 19082 and modified by Ramstedt in 1912.3 An overall complication rate of 10% (4% intraoperative and 6% postoperative) has been reported, with complications including duodenal mucosal perforation, wound infection,4 and postoperative vomiting.5


Eighty years after the conventional open procedure was introduced, laparoscopic pyloromyotomy (LPM) was described.6,7 Over the ensuing years, the minimally invasive approach has gained widespread use and acceptance. Complication rates of 3% to 18% have been reported for LPM.8–11 These complications have included mucosal perforation, incomplete pyloromyotomy, serosal laceration, conversion to open pyloromyotomy, and wound complications. Perceived advantages of LPM, including excellent visualization, shorter time to full feeds, shorter length of stay, and superior cosmesis compared with the open surgery, have made LPM a mainstay of the pediatric surgical armamentarium.


Preoperatively, patients may present with a hypochloremic, metabolic alkalosis due to vomiting and will generally be dehydrated. Aggressive resuscitation and stabilization with a normalized urine output is important prior to surgical treatment of the disease. The bicarbonate level must be normalized through administration of a saline solution, because infants with a metabolic alkalosis will respond with a respiratory acidosis resulting in postoperative apnea. Postoperatively, patients can be advanced on a feeding regimen or ad libitum. Postoperative emesis with feedings is frequent but self-limiting in most cases.


This chapter discusses the preoperative, intraoperative, and postoperative management and pitfalls of both pyloromyotomy procedures.



INDICATIONS



• Persistent, nonbilious emesis.

• Palpation of thickened pylorus or demonstration of pyloric stenosis on ultrasound


OPERATIVE STEPS



Laparoscopic



Step 1 Position and trocar placement

Step 2 Lateral retraction of stomach

Step 3 Hypertrophied pylorus relative to duodenum visualized

Step 4 Incision made in pylorus

Step 5 Hypertrophied fibers split down to mucosa using the laparoscopic pyloric spreader

Step 6 Pylorus halves tested for independent mobility

Step 7 Check for mucosal perforation

Step 8 Trocar removal and closure


Open Pyloromyotomy



Step 1 Incision is made in right upper quadrant or supraumbilical

Step 2 Fascia is opened

Step 3 Stomach and pylorus are delivered gently through wound

Step 4 Hypertrophied pylorus relative to duodenum visualized

Step 5 Incision made in pylorus

Step 6 Hypertrophied fibers split down to mucosa using pyloric spreader and tapered back of knife

Step 7 Pylorus halves tested for independent mobility

Step 8 Check for mucosal perforation

Step 9 Closure


PREOPERATIVE MANAGEMENT


A good outcome after pyloromyotomy is predicated upon adequate preoperative resuscitation. Children with HPS will usually present with a hypokalemic, hypochloremic metabolic alkalosis. The severity of fluid and electrolyte abnormality is reflected by carbon dioxide12 levels, with increased severity correlating with higher levels in the blood. Five percent dextrose and 0.45 normal saline solution suffices in most cases, delivered at 1.5 to 2 times maintenance rate with an initial bolus of 20 ml/kg of the child’s weight. The fluid is supplemented with potassium if the renal function is normal. Approximately 20% to 36% of infants with pyloric stenosis may present with nonclassic hyperkalemia and 12% to 18% with acidosis instead of alkalosis.13 Fluid resuscitation is again paramount.



DIAGNOSIS AND ERRORS


Preoperative work-up of projectile nonbilious emesis involves a careful history and physical examination, drawing a basic metabolic blood panel with bicarbonate and chloride values and, in most instances, obtaining an ultrasound. The sensitivity and specificity of physical examination alone was found to be 72% and 97%, whereas that of ultrasound was 97% and 100%.14 However, false positives on ultrasound resulting in negative laparotomy were reported at an incidence of 0.7% to 5.3%.15,16



OPERATIVE PROCEDURE



Trocar Insertion


See Section I, Chapter 7, Laparoscopic Surgery.



Retraction of the Stomach and Duodenum



Stomach Perforation/Laceration (Laparoscopic and Open)



• Consequence



Intra-abdominal sepsis.

Grade 3/4/5 complication


• Repair



Experienced laparoscopists may choose to repair a laceration or perforation intracorporeally. Otherwise, conversion to an open procedure may be necessary to repair the injury. Postoperative gastric decompression with nasogastric suction, intravenous hydration, and perioperative and postoperative antibiotics are important adjuncts of treatment. Injury during an open pyloromyotomy is less common than with LPM; however, repair of the injury requires a similar approach as outlined previously.

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Jun 21, 2017 | Posted by in GENERAL SURGERY | Comments Off on Pyloromyotomy

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