Neonatal surgery

Question 1

Congenital diaphragmatic hernia

Answer 1

Failure of the dorsal paired plueroperitoneal membranes to close - 85-90% on the left – 1/4000 LBs – 40% have associated extra-pulmonary anomalies

Question 2

Normal embryonic development of the diaphragm

Answer 2

Formed between 4-8 weeks gestation - 4 parts (central tendon, dorsal portion, muscular part, dorsal pair plueroperitoneal membranes)

Question 3

Physiological effects of CDH

Answer 3

Less Lung area –> respiratory distress –>more work to breathe/more air swallowed –> gut expands compressing mediastinium –> increasing intrathoracic compression. Hypoplasia of ispilateral lung, Fewer airway and arteries formed, greater vascular musculature (pulmonary HTN)

Question 4

Diagnosis of CDH

Answer 4

Antenatal ultrasound or MRI to show herniation of abdominal viscera into the thorax
CXR post natally showing loops of bowel in the chest

Question 5

Treatment of CDH

Answer 5

Pre-operative stabilisation – intensive care with endotracheal tube
Surgical reduction and repair (primary or patch)

Question 6

Long term outcome of CDH

Answer 6

Overall survival rate is 70% – chronic respiratory problems which improves over time. Spinal and chest wall deformities – risk of recurrent heniation. Neurodevelopmental sequelae and gastro-oesophageal reflux (17-76%)

Question 7

Congenital cystic adenomatoid malformation

Answer 7

A lobe of the lung is replaced by non-functioning cyst tissue – reduces lung capacity if large and causes diaphragmatic/mediastinal shift
Diagnosed by USS antenatally and usually removed after birth but if severe fetal surgery can be performed

Question 8

Congenital lobar emphysema

Answer 8

A developmental anomaly of the lower respiratory track characterised by hyperinflation of one or more pulmonary lobes – treatment is by selective intubation and surgical removal - dilated but with lung markings.

Question 9

Bronchogenic cyst

Answer 9

A bronchial tree malformation causing mediastinal mass – can cause symptoms due to mass effect or infection, and rarely lead to respiratory distress – surgical excision is the most common managment

Question 10

Oesophageal atresia

Answer 10

1/3000-5000 LB – trachea and oesophagus are foregut derivatives – in the 4th wk lateral mesoderm ridges form in the proximal oesophagus – fuse in the midline to separate the structures on the 26th day of gestation

Question 11

Types of oesophageal atresia

Answer 11

87% - Proximal OA with distal tracheo-oesophageal fistula
8% - Total/isolated OA
4% - Isolated tracheo-oesophageal fistula
1% - Distal OA with proximal tracheo-oesophageal fistula
1% - Proximal OA with proximal & distal tracheo-oesophageal fistulas

Question 12

Cause of Oesophageal atresia

Answer 12

Incomplete separation of the trachea and oesophagus
Notocord abnormalities
Abnormal growth of oesophageal mesenchyme and epithelium
Abnormal neural crest cell migration

Question 13

Cause of tracheo-oesophageal fistula

Answer 13

Incomplete separation
Lateral ridge fusion failure
Tracheal and oesophageal proximity

Question 14

Associations with oesophageal atresia

Answer 14

50-70% – VACTERL & CHARGE

Question 15

VACTERL

Answer 15

Vertebral anomalies, anal atresia, cardiac abnormalities, tracheo-esophageal fistula, renal and limb defects

Question 16

CHARGE

Answer 16

Coloboma of the eye, heart defects, atresia of the nasal choanae, retardation of growth/development, gentiourinary abnormalities & ear problems and deafness

Question 17

Diagnosis of oesophageal atresia

Answer 17

Can be diagnosed antenatally (polyhydramnios) or post-natally
Surgical correction should be performed ASAP based on the spitz classification – based on birthweight above or below 1,500gs and the presence of cardiac abnormalities

Question 18

Forms of Duodenal atresia

Answer 18

40-50% – complete obliteration of the lumen
7-20% – duodenal diaphragm or web
10-30% – Annular pancreas (always associated with stenosed or atresic duodenum)

Question 19

Causes of Duodenal atresia

Answer 19

3/40wks - 2nd portion of duodenum at the junction of the foregut and midgut forms the biliary and pancreatic buds
4-7/40wks - hepatobiliary system differentiation and fusion of dorsal and ventral pancreatic anlagen - duodenal mucosa proliferates causing occlusion and then vacuolisation

Question 20

Incidence of Duodenal atresia

Answer 20

Failure of re-canalisation of duodenal lumen – 1/4000-6000 LBs, M:F equal, no racial predeliction
50% premature and 40% demonstrate polyhydramnios
Look for double bubble on antenatal scans
Link to trisomy 21 (20-30%)

Question 21

Presentation of Duodenal atresia

Answer 21

Vomiting in first few hours of life - bilious stained generally – AXR shows double bubble with no distal air
Consider risk of associated anomalies
Treat with surgery

Question 22

Exomphalos

Answer 22

An abdominal wall defect where contents are herniated within a sac, and is tightly packed (may contain liver). 1-2.5/5000 LBs - associated with other abnormalities in 50% of cases. If sac is intact management is simplex and it is relatively simple to surgically reduce. large, ruptured or liver containing sacs are more complex

Question 23

Other congenital intestinal malformations

Answer 23

Jejunal or Ileal atresia
Anorectal anomalies (imperforate anus)

Question 24

Gastroschisis

Answer 24

An abdominal wall defect where contents are herniated without a sac - loosely organised loops of bowel
4-5/5000 LBs - occurs physiologically 10-13wks gestation
Closure is complex and bowel may be too inflamed to be easily reduced. surgical primary closure is still the aim

Question 25

Urological anomalies

Answer 25

Hypospadias Undescended testicles
Posterior Urethral valves Intersex conditions
Exstrophy of the bladder
Renal tract dilation due to vesicoureteric reflux, pelviureteric junction obstruction, meaureter

Question 26

Associations with duodenal atresia

Answer 26

30% of DA babies have downs, and 3-8% of downs have DA.
VACTERL
Annular pancreas
Other intestinal atresias

Question 27

Associations with Co-arctation of the aorta

Answer 27

15-20% of turners syndrome (also Shone & PHACE)

It is strongly associated with other intracardiac anomalies (75-80% will have a bicuspid aortic valve)

Question 28

Infantile vs adult Co-arctation of the aorta

Answer 28

The infantile forms has diffuse hypoplasia until the PDA - the blood to the lower aorta is via the PDA
The adults form is juxta- or post-ductal and occurs after the PDA closes.

Question 29

Undescended testis

Answer 29

occur in 2-4% of male infants. Much more common if preterm. Can lead to infertility, torsion, testicular cancer and psychological problems. Referred if undescended at 6months and operated on at 1yr.

Question 30

Ectopic ureter

Answer 30

a condition where the ureter terminates not in the bladder but in the urethra (in males) or the urethra or vagina (in females). This will lead to frequent UTIs and continuous drip incontinence. Often associated with duplex kidneys.

Question 31

Spina bifida and hydrocephalus

Answer 31

15-25% of children with SB will have hydrocephalus - if non-communicating this can cause ventricular dilation.

Question 32

Undescended testicles

Answer 32

2-4% of term male infants and 25% bilateral. More common if preterm. Can cause infertility, torsion, testicular cancer or psychological harm. Treat with orchidopexy between 6 month and 1yr.