Approach to Congenital abdominal wall defects .pptx

Approach to a newborn with congenital abdominal wall defects. This will cover about embryological basis and management options for Gastroschiasis, Omphalocele and umbilical hernia

1. Approach to a Newborn with Congenital Abdominal Wall Defects Presenter: Abdi L. (GSR- I) Moderator: Dr Abreham ( Ass’t . Prof. of Pediatric Surgery) Oct., 2022 G.C

2. Objectives To describe embryological basis of congenital abdominal wall defects To discuss clinical presentation and diagnosis of these anomalies To list differences between omphalocele and gastroschisis To explain their complications and principles of management 2

3. Outlines Introduction Embryology of abdominal wall defects Gastroschisis Omphalocele Umbilical hernia Summary References 3

4. Introduction Gastroschisis and omphalocele are the 2 most common congenital abdominal wall defects Often diagnosed prenatally by US Associated with other anomalies in different rate 4

5. Embryology of abdominal wall At 4 th week GA, embryo develops 4 folds that will enclose the body cavities 2 Lateral folds, Cephalic fold and Caudal fold The 2 lateral folds form the pleuroperitoneal canals once they meet anteriorly in the midline. 5

6. Embryo…Cont’d The Cephalic fold brings down with it the developing heart; also carries the septum transversum The Caudal fold brings with it the developing bladder/ allantois The gut tube has communication at the umbilicus to the yolk sac. At 6 th wk - physiological midgut herniation At 10 th wk - the already herniated gut returns to the peritoneal cavity 6

7. Cont’d… 7

8. Cont’d… 8

9. Embryo… Physiological herniation 9

10. Spectrum of congenital abdominal wall defects Gastroschisis Omphalocele Umbilical hernia Pentalogy of Cantrell Exstrophy of bladder 10

11. Gastroschisis Incidence : 1 in 4000 live births; M>F Preterm delivery is more frequent in infants with gastroschisis (28%) The most common of abdominal wall defects Embryology: Caused by failure of the umbilical coelom to develop. The elongating intestine then ruptures out of the body wall directly into the amniotic cavity The defect is almost always to the right of umbilicus (2-3cm diameter) 11

12. Etiology: Different theories Failure of the mesoderm to form in the anterior abdominal wall Failure of the lateral folds to fuse in the midline leaves a defect to the right side of umbilicus Thrombosis of the right omphalomesenteric vein(umbilical vein) causes necrosis of surrounding abdominal wall Maternal use of smoking and vasoconstrictive drugs( ephedrine, cocaine) 12 Gastroschisis

13. Risk factors for Gastroschisis Tobacco, Aspirin and ibuprofen High levels of nitrosamines (environmental exposure) Decongestants ( pseudophedrine ) Use of addictive drugs (cocaine, methamphetamine, marijuana) Low levels of glutathione & a-carotene Young maternal age Low socioeconomic status Primigravida 13 Gastroschisis

14. Clinical Presentation It has no covering membrane Is not associated with chromosomal abnormalities So the survival rate is excellent. But volvulus resulting in a compromised blood supply may lead to fetal death. The most common associated anomaly is intestinal atresia(7-28%) IUGR has been noted in many of these fetuses. 14 Gastroschisis

15. Diagnosis Antenatal 2 nd TM U/S, it also helps to detect associated anomalies Gastroschisis : Detection of Bowel loops freely floating in the amniotic fluid Defect in abdominal wall to right of umbilical cord insertion Elevated alpha fetoprotein (AFP) in both maternal serum and amniotic fluid Elevated amniotic fluid acetylcholinesterase ( AChE ) More increase in gastroschisis 15 Gastroschisis

16. Prenatal mgt and delivery Ideal test is to accurately differentiate gastroschisis fetuses at risk for complications Mode & time of delivery should be based on obstetric indications Literature suggests both SVD and CS are safe Preterm delivery has been advocated to limit exposure of the bowel to amniotic fluid 16 Gastroschisis

17. Cont’d… At time of birth, the bowel is usually normal. About 20 minutes later, the bowel gets changed: edematous and transudation of proteinaceous fluid May be due to exposure to air or related to mesenteric venous occlusion. 17

18. Postnatal Mgt Neonatal care There is significant evaporative water losses from exposed bowel The herniated bowel should be wrapped in warm saline-soaked gauze The baby should be positioned on right side to prevent kinking of mesentery IV fluid resuscitation, NG decompression Central venous access should be established early Examine the bowel for atresia, necrosis or perforation 18 Gastroschisis

19. Postnatal … Risk stratification: Simple or Complex gastroschisis This risk was based on the presence or absence of any intestinal complication (atresia, ischemia, perforation, or NEC) 19 Gastroschisis

20. Surgical Mgt : Gastroschisis Goal: return the bowel with minimal risk Options: Silo placement, serial reductions, and delayed abdominal wall closure Primary reduction with operative closure Bands crossing the bowel loops should be lysed before reduction 20 Gastroschisis

21. Primary closure : gastroschisis After bowel reduction a piece of silastic sheeting can be placed under abdominal wall if there is concern of increased IAP Intra-abdominal Pressure (IAP) can be measured by: Intravesical pressure using bladder catheter Intragastric pressure using NGT Pressures higher than 10-15 mmHg indicates elevated IAP Associated with decreased renal & intestinal perfusion Splanchnic perfusion pressure= MAP – IAP If < 44 mmHg implies decrease intestinal blood flow 21 Gastroschisis

22. Staged silo reduction Placing the bowel into a silo, its base placed or sutured into fascial openings The bowel is reduced 1-2x per day as the silo is shortened by sequential ligation Continuously assess bowel viability while in the silo Definitive closure done when all contents are reduced entirely This process usually takes up to 14 days; majority within 5- 6 days 22 Gastroschisis

23. Definitive closure: sutureless Vs skin Vs fascial closure 23 Gastroschisis

24. Complications Intestinal atresia NEC Short bowel syndrome Prolonged parenteral nutrition related: Cholestatic liver disease Central-line related sepsis 24 Gastroschisis

25. Management of intestinal atresia Depends on the state of intestine, and the time of diagnosing the atresia If detected at time of birth, stoma can be created If diagnosed a few weeks later, operation deferred for 3-4 weeks 25 Gastroschisis

26. Postop course Ensure there are no effects from increased IAP If suspected, prompt laparotomy and silo placement NG decompression Parenteral nutrition Early oral stimulation to prevent loss of sucking reflex 26 Gastroschisis

27. Omphalocele Incidence In utero 1 in 1100; but at birth 1 in 4000-6000 The second most common abdominal wall defect Embryology Failure of the bowel to return to the body cavity from its physiological herniation Develops due to a failure of body folds to complete their journey Most are lateral fold defects 27 Omphalocele

28. Omphalocele … Clinical presentation Is a large defect ( > 4cm), The sac is covered by amnion & peritoneum Contents: small & large intestine, ± liver, stomach, spleen and gonads It has a relatively high incidence of associated defects Chromosomal abnormalities found in > half of patients Trisomies 13,18, 21, 45X, Beckwith-Weideman syndrome, Pentalogy of Cantrell 28 Omphalocele

29. Cont’d…. Most patients are large for gestational age/LGA/ Usually other organ systems are affected as well 45% of patients with omphalocele have a cardiac abnormality. Pulmonary hypoplasia is also commonly associated with omphalocele The severity and number of these associated issues determine the outcomes in omphalocele 29 Omphalocele

30. Risk factors for Omphalocele Extremes of maternal age Maternal obesity Failure to use multivitamins during pregnancy 30 Omphalocele

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33. Prenatal Diagnosis Ultrasound in 2 nd trimester Also useful for detection of associated anomalies Elevation of maternal serum AFP O/HC or O/AC ratios may be correlated with postnatal morbidity & mortality: Giant omphalocele 33 Omphalocele

34. Perinatal care Mode of delivery- CS if obstetric indication However, giant omphaloceles are being delivered by C-section due to fear of liver injury 34 Omphalocele

35. Omphalocele: Initial care Early NG tube placement to decompress the intestines Rectal stimulation to evacuate meconium Maintenance of body temperature Ventilator support as needed IV maintenance fluid –preferable IV access above the diaphragm/ upper limbs 35 Omphalocele

36. Initial care… Prophylactic antibiotics Defect is covered by non-adherent sterile gauze If large omphalocele, babies should be positioned on their side Directed cardiac evaluation- echocardiography Abdominal US- to look for renal abnormalities Check for hypoglycemia=> Beckwith- Weidemann syndrome 36 Omphalocele

37. Risk assessment Based on presence or absence of associated anomalies Isolated or not Location of the bulge in relation to the abdomen Hypogastric, central, and epigastric Based on size Hernias of the cord, small, medium, large, and giant defects 37 Omphalocele

38. Management Non-operative therapy, Primary closure when possible, and Staged reduction with a temporary Silastic ‘pouch ’ These treatment options depend on the size of the defect, GA and presence of associated anomalies 38 Omphalocele

39. Non-operative mgt Scarification treatment If life-threatening associated anomalies, especially cardiac Painting the sac with eschar forming agents Silver nitrate solutions or silver sulfadiazine cream The eschar and epithelialization may take 4-10 weeks. Eventually a covered ventral hernia resulted 39 Omphalocele

40. Operative mgt Immediate primary closure For small to medium sized omphaloceles Excision of the sac, with primary closure of fascia and skin If fascia closure increases IAP, skin closure alone is advisable 40 Omphalocele

41. Mgt… Staged neonatal closure The sac is excised and replaced with mesh and then closed over time Delayed staged closure Attaching Silastic pouch to the fascia allows gradual reduction of contents into abdomen (10-14days), Skin flap closure needed eventually Sometimes prosthetic patch needed to close fascial defect 41 Omphalocele

42. Operative closure 42 Omphalocele

43. 43 Omphalocele

44. 44 Omphalocele

45. Large omphalocele: staged repair 45

46. Ruptured omphalocele: mgt Cover the exposed bowel, and apply silo or mesh can be used. 46

47. Post op care Systemic antibiotics Parenteral nutrition until bowel function returns Respiratory support with ETT Keep NGT till bowel functions/ distention decreased Complications Due to highly increased intra-abdominal pressure after closure: Respiratory distress – mechanical ventilation Acute hepatic congestion – reoperation Renal failure – dialysis Bowel infarction Dehiscence 47 Omphalocele

48. Outcome depends on presence and degree of: prematurity Associated anomalies Loss of bowel length due to atresia or gut infarction Long term outcomes Common in patients with larger omphaloceles GERD Pulmonary insufficiency Recurrent lung infection Feeding difficulty Neurodevelopmental delay 48 Omphalocele

49. Umbilical hernia Failure of umbilical ring to close leads to central defect in the linea alba The protrusion is covered by normal umbilical skin and subcutaneous tissue 20% of full-term neonates may have incomplete closure of umbilical ring at birth. Girls > boys 49

50. Cont’d… The extent of skin protrusion is not always indicative of the size of the fascia defect Palpate the actual facial defect by reducing the hernia manually Premature and LBW infants have a higher incidence 50

51. Umbilical hernia… Generally are asymptomatic Causes considerable parental anxiety Complications like incarceration are rare (0.2%) during childhood Abdominal pain, bilious emesis, tender mass thru umbilicus 80% of umbilical hernias close spontaneously by 4 or 5 years of age. Defects of >1.5cm diameter rarely close spontaneously Surgery is indicated if:- No spontaneous closure by 5 years, Larger defect regardless of age Symptomatic 51

52. Mgt: Umbilical hernia Observation Pressure dressing is not advisable Operative repair Recurrence is rare, but common in children with elevated intraabdominal pressures, like those with a VP shunt. 52

53. Steps for operative repair for umbilical hernia 53

54. Summary 54