Exomphalos
Key points
Approximately 4 in 10,000 UK births
Likely incomplete fusion of lateral body wall folds - weeks 4-10
The sac in exomphalos is made up of 3 layers, inner is peritoneum, middle is Whartons jelly, and outer is amniotic sac
Advanced maternal age is risk
Giant: Liver is herniated
>5cm: Major
<5cm: Minor
>1.5cm: Hernia of the cord - open umbilical ring with abdominal contents in - no fascial defect - still high incidence of associated abnormalities
Antenatal management
Scan bi weekly until 32 weeks, then weekly
Measurements - Exomphalos diameter (ED)/Abdominal circumference ratio
>0.24 concerning for increased likelihood of staged closure, ventilation, hospital stay
Amniocentesis for karyotype
MRI if any CNS defect suspected
Check for heart defects
Distinguish from fatal body stalk defevts
Deliver as close to term as possible - probably needs C-section to avoid rupture which is associated with high mortality and long hospital stay
Associations
Chromosomal anomalies in 30-70% - inversely proportional to size of sac. More frequent in central defects
Pulmonary hypoplasia in 1/3
Beckwith-Wiedemann syndrome
Trisomies 13, 18, and 21
Pentalogy of Cantrell:
1. Exomphalos (epigastric)
2. Lower sternal cleft
3. CDH central tendon
4. Pericardial defect (may have ectopia cordis)
5. Cardiac defect
Omphalocoele extrophy imperforate anus spinal defects (OEIS) complex
Techniques for exomphalos major
Paint and wait
4-10 weeks for paint and wait
Chlorhexidine washes, silver dressings (Atrauman Ag - complication is leucopenia), medihoney
Amnioinversion technique
Undermine skin 1cm margin around sac
Apply goretex sac over top of sac
Squeeze silo over next few days
Post operative complications
Post op - kinking of hepatic veins - hypotension with hepatomegaly
Compartment syndrome
Can have splenic torsion post op
Standard scenario
Concerns are
1. Size of defect, liver out, sac rupture
2. Co-morbidities including Beckwith-Wiedemann, Chromosomal abnormalities
Ensure resuscitation on NICU (pulmonary hypoplasia), cover with film
Check blood glucose
Echo
Prevent
1. Hypothermia
2. Hypoglycaemia
3. Rupture
Examine for above features, abdomino-visceral disproportion, position of testes
Check antenatal scans for features of chromosomal abnormalities and pulmonary hypoplasia
Procedure based on abdomino-visceral disproportion, and pulmonary hypoplasia
In general
<5cm Minor - Primary closure (Unless respiratory insufficiency)
>5cm Major - Primary closure or Paint and Wait depending on abdomino-visceral disproportion
>5cm + liver out (Giant) - Paint and Wait
Risk: Abdominal compartment syndrome
Procedure
Reassess abdomino-visceral disproportion
Excise sac, ligate umbilical vessels and urachus
Do not remove sac from liver (causes severe bleeding)
Check for testes
Separate muscle and skin
Check ventilation pressure then close
Or
Excise sac + place preformed silo (if suitable size available)/Hand sewn silo
Reduce over course of week
Other options:
Amnio-inversion
Paint and Wait
Ruptured sac:
If minor exomphalos - emergency closure as above
If major/giant (not amenable to closure):
Close with sutures if possible
If not posisble -
Excise sac + place preformed/Hand sewn silo
Reduce over course of week
Follow up
Paediatrics for GORD, Respiratory and Neurodevelopmental co-morbidities
Orchidopexy if needed
If paint and wait:
6 monthly reviews to assess reducibility
CT for position of liver and hepatic veins pre op
Delayed closure
Perform with senior colleague
Midline incision avoiding hepatic veins
Locate fascial edges
Component separation if unable to bring fascia together
Special scenario - Pentalogy of Cantrell
1. Exomphalos (epigastric)
2. Lower sternal cleft
3. CDH central tendon
4. Pericardial defect (may have ectopia cordis)
5. Cardiac defect
Ensure resuscitation by neonatal team
Paint and wait approach for exomphalos
Review antenatal history
Examine and test for chromosomal abnormalities
Allow cardiac surgeons to plan staged repairs
Attend theatre if needed to repair diaphragm with patch
Do not close exomphalos until early childhood due to risk of pressure on thoracic cavity
References
Islam, Saleem, et al. "Omphalocele." Pediatric Surgery NaT, American Pediatric Surgical Association, 2021. Pediatric Surgery Library, www.pedsurglibrary.com/apsa/view/Pediatric-Surgery-NaT/829059/all/Omphalocele.
Shailinder Singh, Nottingham Children's Hospital teaching series
Nitzsche K, Fitze G, Rüdiger M, Wimberger P, Birdir C. Prenatal diagnosis of exomphalos and prediction of outcome. Sci Rep. 2021 Apr 22;11(1):8752. doi: 10.1038/s41598-021-88245-0. PMID: 33888820; PMCID: PMC8062495.