What is the role of surgery in the treatment of pediatric gastroschisis?

Updated: Nov 05, 2019
  • Author: James G Glasser, MD, MA, FACS; Chief Editor: Dharmendra J Nimavat, MD, FAAP  more...
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Answer

In 1969, Allen and Wrenn adapted Schuster's technique to gastroschisis. [50] Silon (Dacron-reinforced Silastic) sheets are sutured to the full thickness of the abdominal wall defect and closed over the eviscerated intestine, creating a silo. Reduction is facilitated by stretching the abdominal musculature, emptying the stomach and bladder, and manually evacuating the colon. The silo is gently squeezed each day; usually a week is required to effect reduction of the extruded viscera. The critical factor is resolution of inflammation; in time, the stiff, congealed intestines become normal—soft and pliable—and can fit into the nooks and crannies of the abdominal cavity. [51, 52]

Adhesions may develop between the intestines and the silo or the abdominal wall defect. For this reason, Dr Jennings advocates applying Seprafilm over the intestines before placing the silo. [46]

Excessively tight closure of the abdominal cavity causes increased intra-abdominal pressure (abdominal compartment syndrome), which limits diaphragmatic excursion, impairing ventilation. Increased peak inspiratory pressure (PIP) is required, but this will decrease venous return. Increased heart rate is required to maintain cardiac output. If renal blood flow diminishes, glomerular filtration rate will also decrease, and urine output will fall; renal failure or renal vein thrombosis may ensue. Diminished mesenteric blood flow causes ischemia and augments the risk of necrotizing enterocolitis (NEC), because dysmotility leads to stagnation and bacterial overgrowth, and the bowel is immunologically immature. [53]

Avoid PIPs greater than 25 mm Hg. High-frequency oscillatory ventilation is an alternative to conventional ventilation, if intra-abdominal pressures are markedly increased. [54]

The intra-abdominal pressure is measured by connecting a manometer to a Foley catheter or a nasogastric tube. The central venous pressure, intravesical pressure, and the intragastric pressure should not exceed 20 cm H2O to avoid development of abdominal compartment syndrome. [24]

Alternate ways of managing infants with abdominal wall defects generate lively discussion among colleagues. When disparate techniques yield equivalent results, when no technique is demonstrably superior, personal preference is determinative.

The dilemma is balancing the goal of replacing the extruded viscera and closing the abdomen against the attendant complications, most notably abdominal compartment syndrome, which follows the degree of viscera-abdominal disproportion. Minimizing intra-abdominal hypertension (IAH) is critical.

An intra-abdominal pressure above 15 mm Hg is high; that exceeding 20 mm Hg is excessive and likely to precipitate abdominal compartment syndrome. The effects of IAH are both hemodynamic and ventilatory. Reduced cardiac output diminishes splanchnic and renal perfusion, which leads to oliguria and gut acidosis. Hypoventilation (hypercarbia and hypoxia) compounds the metabolic acidosis. Abdominal compartment syndrome has devastating physiologic complications, including renal failure, sepsis, bowel ischemia, and wound complications.

Bowel ischemia leads to NEC, which may cause short-bowel syndrome. Wound complications include dehiscence, sepsis, and enterocutaneous fistulae. Excessively tight closure of gastroschisis may be a factor in as many as 75% of patients referred for intestinal transplantation. [55]

Controversial issues include the following:

  • Should these infants be delivered by cesarean delivery or vaginally?

  • Should a prefabricated silo be placed in the neonatal intensive care unit (NICU) with sedation, or in the operating room (OR) under general anesthesia? Does it matter?

  • Can the intestines be more thoroughly cleansed and the anatomy better assessed in the OR rather than in the NICU?

  • Are "off the shelf" silos preferable to those fabricated by the surgeon from Silon sheets?

  • Does stretching the flaccid (paralyzed) abdominal wall enlarge the abdominal cavity?

  • Is enterolysis of the inflamed intestine, cutting through the inflammatory peel and separating the congealed loops of intestine feasible, or is the risk of damaging the intestine prohibitive?

  • Should an attempt be made to evacuate meconium from the intestine?

  • Does squeezing the intestine injure the serosa and promote the formation of adhesions?

  • Should the appendix be removed and the opening in the cecum used to evacuate the meconium?

  • Should the surgeon dilate the anus and milk the meconium through the colon into the rectum and out the anal canal?

  • If a silo is placed, should pressure be applied to the eviscerated intestine, and does this pressure enlarge the abdominal cavity as opposed to the Jennings approach?

  • Is resolution of inflammation the determinative factor in achieving reduction? Is squeezing the silo necessary? Simply allowing the intestine to sink by gravity into the abdominal cavity may be sufficient.

  • When should a silo be removed to minimize the risk of infection?

  • Which antibiotics should be used?

  • Should the antibiotic cover gut or skin flora?

Many surgeons favor placement of a prefabricated silo in the nursery with gradual reduction of the extruded intestine. Criteria that preclude this technique include poor bowel perfusion (a small, constricting defect), or bowel and/or mesentery attached to the abdominal wall defect, gross viscera-abdominal disproportion, and deteriorating metabolic acidosis. [55, 56]

Vigilance is necessary during reduction to ensure that the intestines are actually moving into the peritoneal cavity as the silo is squeezed. Otherwise, bowel loops may be compacted together or pressed against the ring of the silo or the margins of the defect, causing congestion or ischemia. Any sign of venous congestion mandates removal of the silo and inspection of the intestines. Necrosis of the duodenum from the ring of the silo abutting its anterior wall has been reported. [56] (See the image below.)

Pediatric omphalocele and gastroschisis (abdominal Pediatric omphalocele and gastroschisis (abdominal wall defects). In this infant, gastroschisis has been complicated by jejunal atresia and loss of the entire distal small bowel (the grey tissue).

The baby in the image above is truly remarkable. She was born with jejunal atresia and necrosis of the distal small intestine and necrosis of the antimesenteric aspect of the atretic jejunum. This was excised, and the remaining intestine was tubularized. Ultimately, it became dilated; we utilized the serial transverse enteroplasty (STEP) procedure [57] and created an anastomosis to the distal microcolon. Anastomotic stricture occurred and required several revisions, but each time the proximal intestine dilated, making it amenable to additional STEP procedures. This infant was referred for an intestinal transplantation, which proved to not be necessary.

See the images below.

Pediatric omphalocele and gastroschisis (abdominal Pediatric omphalocele and gastroschisis (abdominal wall defects). Following lysis of adhesions and tubularization of the viable, mesenteric portion of the proximal jejunum, the eviscerated viscera are reduced and the gastroschisis abdominal wall defect is closed.
Pediatric omphalocele and gastroschisis (abdominal Pediatric omphalocele and gastroschisis (abdominal wall defects). The radiograph shows the intestine following multiple serial transverse enteroplasty (STEP) procedures.
Pediatric omphalocele and gastroschisis (abdominal Pediatric omphalocele and gastroschisis (abdominal wall defects). This child, approximately age 30 months in the photo, had a successful repair. Her clinical course is described above.
Pediatric omphalocele and gastroschisis (abdominal Pediatric omphalocele and gastroschisis (abdominal wall defects). This image shows the appearance of the dilated bowel prior to performing the serial transverse enteroplasty (STEP) procedure.
Pediatric omphalocele and gastroschisis (abdominal Pediatric omphalocele and gastroschisis (abdominal wall defects). This is the intestine as it appeared after the serial transverse enteroplasty (STEP) procedure.
Pediatric omphalocele and gastroschisis (abdominal Pediatric omphalocele and gastroschisis (abdominal wall defects). This is the intestine as it appeared after the serial transverse enteroplasty (STEP) procedure.

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