When Shane was born, his parents noticed that he was missing the distal end of his small finger on the right hand and a webbing between the small and ring finger on the left. He also had an indentation in his left calf that was circumferential. His 6 year old brother said “his leg looks just like the Michelin tire man”.
What is amniotic band syndrome?
Amniotic band syndrome is also known as congenital constriction band syndrome and Streeter’s Dysplasia.
Amniotic banding occurs in utero but may not be apparent until the infant is delivered. Fibrous bands that originate from the amniotic sac can encircle part of the fetus resulting in amputation or scarring. The amniotic sac usually fuses to the chorion early in pregnancy but in rare instances this fusion is incomplete. The unfused amniotic sac then develops tears resulting in bands of fibrous tissue that float in the fluid around the baby wrapping around appendages that are in motion.
Is amniotic band syndrome common?
Amniotic banding is rare but can affect up to 1 in 1,200 live births. Up to 50% of cases have other congenital anomalies including cleft lip, cleft palate, and clubfoot deformity. Hand and foot anomalies occur in up to 80%.
What causes amniotic banding?
There is uniform agreement that this condition is not genetic. It would be incredibly rare that this would occur more than once in a family.
During the later part of pregnancy, as the fetus grows but the bands do not, the bands become constricting. This reduces blood circulation which results in congenital amputations with the affected tissue being reabsorbed.
What are the symptoms of amniotic band syndrome?
The constriction of appendages by amniotic bands may result in:
- Constriction rings around the digits, arms and legs
- Because the scarring from these bands is rigid and tight, nerve and tendon function may be compromised with growth. Club foot deformities, club hand deformities and nerve palsies can be seen distal to the band scar.
- Swelling of the extremities distal to the point of constriction (congenital lymphedema)
- Amputation of digits, arms and legs (congenital amputation)
- Syndactyly (webbing of fingers and toes) because the bands have bound the digits together
- Although controversial, some parents report that their children appear to have pain associated with very tight bands
How is amniotic band syndrome diagnosed?
Amniotic band syndrome is often difficult to detect before birth because the fibrous bands are small. Often the bands are detected on ultrasound indirectly because of the constrictions and swelling of limbs and digits. If necessary, high resolution ultrasound can be used to further define the extent of the syndrome.
How is amniotic band syndrome treated?
Depending on its severity and location, treatment begins after birth. Circumferential bands tend to become more constricting over time and growth compromises function and appearance. Most are managed by surgical excision of the constricting scar. The adjacent tissue is then rotated into a new orientation that allows normal growth as the child matures.
What is the long-term outlook for my child?
Kids who are born with differences learn to manage and lead normal healthy lives. This is because parents praise and encourage their kids for their efforts at new tasks and situations. A study through the Shriners Hospital system documented that children with congenital amputations are more satisfied with their bodies than their typical peers. They learn at an early age that “different” is O.K.
Shane underwent surgery at 14 months of age to release the constriction band around his left calf and reconstruct the web space between his ring and small fingers. Today, when asked about the scar on his leg, he says he was bit by a shark. No one even notices the scars in his web space.