Chapter 4 of 6 · Surgical Management
Myotomy technique
Performing the myotomy and muscle spreading
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Educational content from recorded physician discussions — not medical advice. Talk to your (or your child's) care team about your situation.
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What the experts said
Ultrasound criteria for pyloric stenosis are muscle limb thicker than 4mm, channel longer than 17mm, and pyloric muscle shouldering.
Patient is positioned perpendicular to the axis of the operating table with the operating team at the patient's feet.
A 5mm trocar is placed at the umbilicus for the camera; stab incisions are used for operating instruments.
The right upper quadrant incision is placed at or just above the liver margin to allow liver retraction if needed.
The left upper quadrant incision is placed in a high paramedian position to allow the spreader to approach the pylorus directly rather than tangentially.
Intraabdominal pressure of 10mmHg and flow rate of 1.5L per minute are used throughout the procedure.
Flow rate may be increased if there is a leak around the stab incisions.
The distal extent of the thickened muscle is identified by the vein of Mayo or junction of the white colored wall of the stomach and the salmon colored wall of the duodenum.
Coagulation is used to mark the pyloromyotomy line between the proximal and distal extents.
The surgeon should not extend the myotomy beyond the originally labeled extents.
Cutting current is used to initiate the myotomy; coagulation should not be used for the myotomy in order not to transmit heat to the underlying mucosa.
The myotomy is deepened 2 to 3mm before the beginning of muscle spreading.
Deepening the myotomy should always start in the center or proximal extent, never on the duodenal end.
A controlled but deliberate force should be applied to spread the muscle, observing the muscle layer separating to visualize the underlying submucosa.
The right angle spreader is preferred on the last few fibers on the duodenal end because the heel of the instrument protects the mucosa while the tip spreads the muscle.
One should not insist on separating the last few fibers on the duodenal end if the pylorus is stiff, as this is the point at which a duodenal perforation may occur.
Incomplete myotomies occur on the gastric, not the duodenal end.
An adequate myotomy should allow each limb of the muscle to move independent of the other.
Intact duodenal mucosa is best proven by direct visualization.
The duodenal bulb is occluded and the stomach is insufflated with 30mL of air through an orogastric tube to examine the myotomy site for an air leak.
Air leak testing is less important than direct visualization for confirming mucosal integrity.
A missed duodenal perforation is the most serious complication of a laparoscopic pyloromyotomy.