ABDOMINAL WALL DEFECTS in neonate and older childrenx

Abdominal wall defect
Clinical présentation
Management

1. ABDOMINAL WALL DEFECTS GASTROSCHISIS OMPHALOCELE Pres : Biko Martin Supervisor: Dr.Oyania Felix

2. Introduction Congenital anomalies account for 10% of global neonatal deaths, with children in LMICs being disproportionately affected Major congenital abdominal wall defects ( gastroschisis and omphalocele ) may account for up to 21% of emergency neonatal interventions Gastroschisis (GS) and omphalocele (particularly with ruptured sac) are associated with fluid shifts and physiological alterations that make management challenging in the resource-constrained setting

3. In many LMICs, the reported mortality is 30–100%, while in high-income countries (HICs), mortality in infants with major abdominal wall defects is less than 5%

4. Gastroschisis GS is a full-thickness paraumbilical abd wall defect usually associated with evisceration of bowel and sometimes other abdominal organs . The overall incidence is 4.3 per 10,000 live births Small and large bowel and sometimes other intra-abdominal viscera herniate into the amniotic cavity and are bathed by amniotic fluid in utero The frequency of intrauterine fetal demise is low, although the incidence of preterm delivery and intrauterine fetal growth restriction may be high

5. GS is generally not associated with other congenital anomalies, but 5–20% may have neuromuscular, cardiac, pulmonary, renal, or urological abnormalities Chromosomal abnormalities are uncommon in infants with GS GS has been associated with teen pregnancies with maternal < 20 years and age-independent nulliparity

6. Other risk factors of GS exposure to cigarette smoke illicit substances alcohol environmental chemicals; nitrosamines such as atrazine, cyclooxygenase inhibitors such as aspirin and ibuprofen, decongestants such as pseudoephedrine and phenylpropanolamine, and pain relievers/addiction agents such as opioids; antihistamines; antithyroid medications and radiation lower maternal BMI Poor nutrition

7. Other risk factors of GS.... Low SES Urinary and sexually-transmitted infections acquired shortly before or during the first trimester of gestation possibly due to altered immune responses.

8. Gastroschisis.... Classic-appearing gastroschisis with the abdominal wall defect to the right of the cord insertion (the yellow clamp is on the umbilical cord)

9. Anatomical Origin of GS (pathogenesis) In GS, there is an incomplete fusion of lateral body wall folds of the embryo to form the anterior body wall. Occurs normally during the 4th week of gestation The etiopathogenesis leading to the observed pathoanatomy of GS is poorly understood. Several hypotheses have been proposed: Failure of mesoderm to form in the body wall Rupture of the amnion around the umbilical ring Abnormal involution of the right umbilical vein leading to weakening of the body wall Disruption of the right vitelline artery with subsequent body wall damage

10. Gene polymorphisms that interact with environmental factors, such as smoking, may play a role in pathogenesis The maternal immune response to new fetal antigens of paternal origin may also play a role There is no high-quality evidence that any drug causes gastroschisis , but a possible association has been reported for aspirin, ibuprofen, and vasoconstrictive agents ( eg , pseudoephedrine) Use of acetaminophen in the first trimester has been reported both to lower the risk of GS and to increase the risk

11. The prevalence of GS appears to be higher in areas where agricultural chemical levels in surface water are high and when conception occurs in the spring, the time when agricultural chemicals (eg, atrazine) are commonly applied

12. CLINICAL SIGNIFICANCE Bowel herniation may lead to a variety of intestinal abnormalities: Mesenteric blood supply can become compromised Bowel wall can become inflamed from prolonged exposure to amniotic fluid Other common potential sequelae of gastroschisis include: Growth restriction (30% to 60% of cases), Spontaneous preterm birth (30% to 50% ), Fetal demise (3% to 6%) Growth deficiency may be due to undernutrition from loss of protein and fluid across the exposed bowel

13. Abnormal Doppler measurements, indicative of placental insufficiency, have been observed in a minority of cases The increased risk of fetal demise may be related to placental insufficiency, cord compression, undernutrition, other undefined factors, or a combination of factors

14. Classification of GS Classified into simple and complex types based on the condition of the bowel Simple gastroschisis : the bowel is in good condition with no intestinal complications Complex gastroschisis: GS is associated with congenital intestinal complications in the form of an atresia, perforation, ischemia, necrosis, or volvulus Closed or closing gastroschisis (subset of complex GS):the abdominal wall defect closes around the prolapsed bowel, resulting in exit and/or entry intestinal stricture, atresia,ischemia, necrosis, or resorption

15. In extremely-rare cases, known as the “ vanishing gut syndrome ”, the abdominal wall defect closes completely prenatally, resulting in extreme short gut Infants with complex gastroschisis, occurring in 17% of cases, have significantly higher mortality rates (16.67%) compared to those with simple gastroschisis (2.18%)

16. Complex gastroschisis.... Infants with complex gastroschisis also suffer from significantly higher rates of morbidities They are started on enteral feeds later, they take longer to reach full enteral feedings, and require a longer duration of TPN They have a higher risk of sepsis, SBS, and NEC They tend to stay longer in the hospital and are more likely to be sent home with enteral tube feedings and TPN

17. Prenatal diagnosis GS can be diagnosed on prenatal ultrasound scans as early as 12 weeks’ gestation GS should be suspected when there is; Appearance of eviscerated bowel, with features such as bowel dilatation and/or wall thickening; Absence of a covering membrane or a sac; Identification of the site of cord insertion relative to the defect (the defect is paraumbilical, most often right-sided); Identification of eviscerated organs; and Identification of associated malformations Elevation of maternal serum α-fetoprotein (up to 9 multiples of the mean) is also an indicator of the presence of a foetus with GS - however also elaveted in other abdominal wall defects

18. Prenatal ultrasound

19. Management Principles; Prenatal care; Delivery at a specialized center with expertise in monitoring and pediatric surgery; Management guided by the physiological stability and condition of the intestine; Close monitoring of general condition, respiratory condition, and bowel viability; Reduction of the bowel back into the abdominal cavity with minimal injury; Initiation and optimal management of enteral feeding.

20. Prenatal Management Once GS is diagnosed, fetal growth and amniotic fluid volume are measured by sonographic assessment at 3–4-week intervals starting at 24-weeks’ gestation Oligohydramnios related to fetal growth restriction and is a risk for cord compression Polyhydramnios may be predictive of bowel atresia Growth restriction in fetuses with abdominal wall defects may predict increased adverse neonatal outcomes

21. Although fewer infants with isolated gastroschisis have chromosomal anomalies, the risk is higher in those with extra intestinal structural abnormalities. In these cases, amniocentesis may be warranted for evaluation and further management

22. Delivery and early postnatal care The best method, as well as optimum timing of delivery for infants with GS, is debatable Typically spontaneous onset of labour in GS will occur by 36 weeks of gestation, with the route of delivery largely determined by obstetric indications Several studies have advocated earlier delivery, based either on the development of bowel ischaemia, complicated GS or upon reaching a gestational age of 38 weeks

23. Approx. 30 to 40% of pregnancies with GS go into spontaneous preterm labor and delivery, compared to 6% in the controls The higher rates of preterm labor have been attributed to the presence of increased levels of pro-inflammatory cytokines (IL-6 and IL-8) in the amniotic fluid A study recommended delivery as early as 37 weeks in order to minimize prenatal and postnatal mortality for fetuses with GS The primary determinant of outcome in infants with GS is the extent of intestinal injury that occurs during fetal life

24. Because of the exposed bowel in GS, heat and fluid losses are a major challenge Also, relative intestinal hypomotility makes them prone to vomiting and aspiration pneumonitis

25. Early management includes; Passage of a nasogastric tube to decompress the stomach and protect the airway, Adequate fluid resuscitation, and Bowel protection

26. Postnatal management In the delivery room, it is critical to protect the herniated bowel by; covering it in warm, saline-soaked gauze, Placing it in a central position on the abdominal wall and covering with a plastic wrap or a plastic bag to decrease evaporative heat and fluid losses The infant should preferably be positioned in the right lateral decubitus position to prevent vascular damage because of twisting of the mesenteric vascular pedicle

27. Surgical management The goals of surgical management include; Reduction of the herniated viscera into the peritoneal cavity while avoiding direct trauma to the bowel and excessive intra-abdominal pressure, and Closure of the abdominal wall defect

28. Predictors of the type and timing of surgical intervention The condition of the exposed bowel The degree of abdominovisceral disproportion Gestational maturity The infant’s weight Co-morbidities

29. Surgical options.... Primary reduction, with either immediate sutured closure or sutureless closure; Prosthetic silo placement - gradual visceral reduction followed by delayed sutured or sutureless closure

30. Primary reduction Usually performed if the herniated bowel can be safely placed back into the abdominal cavity without causing excessive intra-abdominal pressure Can be performed in the NICU under mild sedation/analgesia however some cases may need ETT In rare cases, the narrow fascial defect can compromise intestinal blood flow, and may require urgent enlargement of the defect to preserve bowel perfusion and facilitate reduction

31. Abdominal compartment syndrome A serious and potentially-life-threatening complication after primary closure Characterized by respiratory compromise, and/or lower limb, renal and intestinal ischemia Intra-gastric or intra- vesical pressures >20 mmHg, or central venous pressure >4 mmHg have been shown to correlate with decreased perfusion to the kidneys and bowel, and potential risk of compartment syndrome

32. Peak inspiratory pressures of <25 cm H2O on the ventilator after closure also predicts low risk for abdominal compartment syndrome Following the reduction of the bowel into the abdominal cavity, the defect is closed either by sutured fascial closure technique or by sutureless closure technique

33. Primary reduction of gastroschisis

34. Staged Reduction Achieved by the placement of a spring-loaded silo that provides coverage to the exposed bowel, with subsequent definitive closure of the defect Can be used as initial therapy and also following failure of primary reduction The spring-loaded ring of the silo is inserted through the abdominal wall defect and rests beneath the fascia inside the abdominal cavity without the need for placement of fascial sutures

35. The procedure can be performed at the bedside under mild sedation/analgesia, without the need for endotracheal intubation The transparent bag covers the eviscerated bowel, which is reduced daily by tying umbilical tapes around the bag Once the bowel is completely reduced into the abdomen, closure is performed using either the sutured fascial closure or the sutureless closure techniques

36. Staged reduction of gastroschisis: Shown in a picture with the bowel loops placed in a silo Bowel loops reduced into the abdomen using a silo

37. Sutureless closure First described by Sandler et al. , the “plastic” sutureless closure technique utilizes the umbilical cord, left deliberately long at the time of birth, as a biologic dressing After careful reduction of the eviscerated bowel into the abdomen, the defect is covered with the umbilical cord cut and tailored to fit the opening. A clear plastic dressing (Tegaderm 3M) is placed over the defect, which is then allowed to heal by secondary intention.

38. The umbilical-cord-covered defect contracts circumferentially resulting in a scarless abdomen and a cosmetically-acceptable appearance of the umbilicus in 2–4 weeks This technique can be used after primary reduction as well as following staged reduction with silo placement In silo placement, the cord is wrapped in Vaseline gauze and kept moist while the silo is in place or placed inside the silo to maintain viability

39. The infant shown in this image underwent a primary sutureless closure soon after birth. Shown at 19 days of age, he is on full oral feeds Sutureless closure

40. Primary reduction vs Staged reduction The optimal timing of abdominal wall closure in GS remains debatable, with general agreement that early reduction is best. Staged reduction with silo placement has the theoretical advantage of; Achieving reduced intra-abdominal pressure at the time of definitive closure, leading to improved splanchnic perfusion , faster return of bowel function, reduced rates of infection and NEC and decreased risk of long-term bowel dysfunction Placement of a silo also allows for ongoing assessment of bowel perfusion through the transparent bag

41. A recent large, multicenter retrospective observational study comparing infants who underwent immediate closure with those who had a silo placed for ≤5 days Findings: Generally-equivalent outcomes, except for a higher incidence of ventral hernias in infants who underwent immediate closure compared to those who had silo placed for a short duration

42. Sutured Closure vs. Sutureless Closure In a large, single-center cohort study, sutureless repair was associated with significant reduction in duration of mechanical ventilation and pain medication requirements, but with an increased risk of umbilical hernias, compared to sutured closure

43. Algorithm for reduction and closure of gastroschisis

44. Nutrition Infants with GS frequently require prolonged PN due to intestinal ileus and dysmotility, resulting in variable degrees of feeding intolerance TPN and gastric decompression should be provided during the abnormal intestinal motility period until enteral feeding is initiated Prolonged exposure to PN and delay in enteral feeding contributes to cholestasis, feeding intolerance, and risk of late-onset sepsis Early introduction of enteral feeding is recommended, particularly direct feeding or suction feeding. Breast milk is significantly associated with a sooner home discharge

45. Antibiotics should be discontinued within 48 h of abdominal wall closure in the absence of culture-positive sepsis or clinical instability Cryptorchidism is common in gastroschisis, occurring in approximately 35% of all male infants. It is postulated that increased intra-abdominal pressure is responsible for the normal descent of the testis, and in gastroschisis, forces that promote testicular descent are absent. However, there is a high rate of spontaneous migration during the first year of life, with nearly 50% of the testes relocating without intervention

46. Prognosis Dependent on the condition of the bowel at birth GS is associated with significant morbidities that may result from the primary disease or the surgical procedure; including sepsis, necrotizing enterocolitis, short bowel syndrome, intestinal atresia, bowel obstruction, and volvulus which influenced the neonate’s final prognosis Complex gastroschisis is associated with increased, up to 7-fold, in-hospital mortality as compared to simple gastroschisis

47. Higher incidence of cardiac and pulmonary comorbidities in neonates with complex GS in the presence of other comorbidities may also contribute to the poorer outcome for complex patients

48. Summary of mgt

49. Omphalocele Midline abdominal wall defect (absent skin, fascia, abdominal muscles) of variable size at the base of the umbilical cord The defect is covered by a three-layer membranous sac consisting of amnion, Wharton's jelly, and peritoneum The cord/umbilical vessels insert at the apex of the sac, which typically contains herniated abdominal contents

50. Omphaloceles are categorized as either non-liver-containing (containing bowel loops) or liver-containing Small defects generally can be closed in the first 24 to 72 hours of life The remaining spectrum of defects usually involves some type of silo in the first 24 hours of life and delayed closure

51. Prevalence and Epidemiology Its incidence is 1–3 per 10,000 live births The occurrence of omphalocele appears to be more common in offspring of mothers at the extremes of reproductive age (<20 or >40 years) Associations between occurrence of omphalocele in offspring and maternal obesity and in utero SSRI exposure have been reported in some studies Also been associated with male sex and multiple births

52. EMBRYOLOGY AND PATHOGENESIS During the 4th to 5th week of development, the flat embryonic disk folds in four directions and/or planes: cephalic, caudal, and right and left lateral. Each fold converges at the site of the umbilicus, thus obliterating the extraembryonic coelom. The lateral folds form the lateral portions of the abdominal wall, and the cephalic and caudal folds make up the epigastrium and hypogastrium . Rapid growth of the intestines and liver also occurs concurrently.

53. During the 6th week of development, the abdominal cavity temporarily becomes too small to accommodate its contents. This results in protrusion of the midgut into the residual extraembryonic coelom at the base of the umbilical cord. This temporary herniation involves 90 degrees of counterclockwise rotation of the midgut around the superior mesenteric pedicle and is called physiologic midgut herniation.

54. It is sonographically evident in the 9th to 11th postmenstrual weeks (up to crown rump length 45 mm) Reduction of the hernia involves further rotation to 270 degrees in the abdominal cavity and normally occurs by the 12th postmenstrual week; thus, midgut herniation is no longer physiologic beyond the 12th week

55. Pathogenesis The pathogenesis of omphalocele has not been definitively established, but two mechanisms have been proposed: In one, the extraembryonic gut fails to undergo the obligatory 270 degree counterclockwise rotation back into the abdomen, resulting in a simple, small, midline omphalocele In the other, failure of the left and right lateral folds to close normally creates a large abdominal wall defect through which contents of abdominal cavity (including the liver) can herniate The rectus abdominis muscles insert laterally into the costal margins instead of meeting in the midline at the xiphoid.

56. Prenatal diagnosis Increases the chance of identifying some syndromes prenatally Provides time for parents to learn about and adjust to the abnormality Over 90% are diagnosed prenatally as part of an obstetric ultrasound examination Non-liver-containing omphalocele can be made reliably after 12 postmenstrual weeks Liver-containing omphalocele can be made by transvaginal sonography as early as 9 to 10 postmenstrual weeks

57. Findings on ultrasound An omphalocele appears as a midline abdominal wall defect of variable size in the area of the umbilicus Its covered by a membranous sac consisting of amnion as the outer layer, peritoneum as the inner layer, with Wharton's jelly in between Contains abdominal contents (typically bowel but often liver and occasionally stomach or bladder) The cord inserts into the apex of the sac. Ascites may be seen in the sac or the abdomen.

58. Non-liver containing omphaloceles are commonly associated with a fetal aneuploidy, while the larger liver-containing omphaloceles are usually associated with euploid fetuses Sagittal view of a fetus with trisomy 18 at 12 weeks of gestation with an omphalocele and cystic hygroma

59. Arrow points to omphalocele sac containing fluid and fetal liver 3D ultrasound examination of a fetus with an omphalocele at 15 weeks gestation

60. Associated abnormalities Structural anomalies Gastrointestinal abnormalities (eg, malrotation, intestinal or anal atresia) Cardiac defects (eg, ventricular septal defect, tetralogy of Fallot, dextrocardia) Genitourinary anomalies (eg, renal or bladder agenesis, polycystic kidney, hydronephrosis, ureteral stenosis/duplication/ectopic placement) Orofacial clefts, neural tube defects, and diaphragmatic defects Chromosomal anomalies 60% of small omphaloceles are associated with fetal aneuploidy, particularly trisomy 18 or 13 Amniotic fluid volume Polyhydramnios is common after 20 weeks of gestation

61. Syndromes commonly associated with omphalocele Syndrome Prominent findings Schisis association Omphalocele Neural tube defect Oral cleft Diaphragmatic hernia Beckwith-Wiedemann syndrome Omphalocele Macroglossia Gigantism Pentalogy of Cantrell Omphalocele Lower sternum defect Anterior diaphragm defect Parietal pericardium defect Congenital heart anomalies OEIS complex Omphalocele Bladder exstrophy Imperforate anus Spinal malformation

62. Syndrome Prominent findings Donnai-Barrow syndrome Omphalocele Diaphragmatic defects Absence of corpus callosum Hypertelorism Myopia Sensorineural deafness Shprintzen-Goldberg omphalocele syndrome Omphalocele Mildly dysmorphic facies Scoliosis Learning disabilities Pharyngeal and laryngeal hypoplasia

63. PRENATAL CARE Parental counseling Provided by a team of maternal-fetal medicine specialists, neonatologists, pediatric surgeons, and genetic counselors working in collaboration Fetal follow-up Serial sonography to monitor fetal growth Nonstress test/biophysical profile Location, timing, and route of delivery Location - Preferably a tertiary care center Timing - Expectant management is reasonable until spontaneous labor or at least 39+0 weeks Route of delivery - a trial of labor and vaginal birth in the absence of standard indications for cesarean birth - C/S for fetuses with giant omphaloceles

64. Early Postnatal care In the delivery room, the key is to avoid clamping the umbilical sac The immediate care of the newborn with omphalocele involves: Sterile wrapping of the bowel to preserve heat and minimize insensible fluid loss Insertion of an orogastric tube to decompress the stomach Stabilizing the airway to ensure adequate ventilation Establishing peripheral intravenous access Positioning left-side down right-side up if low blood pressure, tachycardia, or dusky bowel appearance suggesting vascular compromise

65. One approach is to place gauze dressings soaked in warm sterile saline and cover the dressing with clear plastic wrap Surgery of omphalocele is not an emergency procedure as long as the amniotic sac remains intact Newborns should be placed in a sterile plastic bag to avoid fuid and temperature loss

66. Intravenous fluids and broad spectrum antibiotics are administered Cardiopulmonary system of the newborn with omphalocele requires careful investigation, including echocardiography Concomitant pulmonary hypoplasia in giant omphalocele might require early intubation and ventilation

67. Surgical closure of the defect The definitive treatment of an omphalocele depends on a number of considerations such as; The integrity of the sac, The size of the defect, The presence of associated anomalies, and The gestational age of the child The size of the fascial defect may be classifed as omphalocele major (≥5 cm of fascial defect) or omphalocele minor (<5 cm of fascial defect) Surgical closure is categorized as; Primary closure, Staged closure and Delayed closure

68. Primary closure Involves excision of the amniotic sac and closure in layers (fascia and skin) It is standard in small defects (2–5 cm), but could also be performed in large defects Single stage, early closure could be achieved in giant omphaloceles using either the anatomical closure in layers or the insertion of a synthetic patch into the fascia followed by skin closure

69. Staged closure Gradual reduction using the amniotic sac itself and sequential ligation Staged closure using a synthetic prosthesis constructed like a silicon chimney is a useful method in giant omphaloceles Delayed closure Escharotic therapy can be done in selected cases, especially when primary closure is not feasible Silver sulfadiazine is a commonly used escharotics agent. Patients could be kept in the ward and do not need intensive care treatment Feeding is well tolerated during this treatment option

70. Treatment could be continued at home, including compressive dressing of the sac. Closure of the resulting abdominal hernia could be scheduled at the age of 6–12 months. Ventral hernia formed following non-operative management of omphalocele

71. The AKTH Kano omphalocele algorithm (adapted from Sowande et al.)

72. Prognosis The overall reported survival rate of live-born omphalocele cases is 75–81% in the current literature. The outcome for omphalocele correlates directly with the size of the defect Patients with isolated omphalocele have the best 1-year survival, which is greater than 90% Giant omphalocele have an in-hospital mortality of up to 20% Long-term medical problems occur such as g astroesophageal refux, pulmonary insufficiency, recurrent lung infections or asthma, feeding difculties, and failure to thrive

73. THANK YOU FOR LISTENING