Amniotic Band Syndrome

 

Vigy Elizebth Cherian

Assistant Professor, Sharda University, Greater Noida, NCR, Delhi

 

ABSTRACT:

Amniotic band syndrome is a well-known condition potentially associated with a variety of different birth defects. The abnormalities occur after the affected parts of the body have formed normally in early development. The severity of amniotic band syndrome can range from a single, isolated finding to multiple, disfiguring complications. The arms and legs are most often affected. The head and face and, in some patients, various internal organs can also be affected. The exact cause of amniotic band syndrome is unknown and controversial. Treatment differs depending on the severity of the condition and the areas of the body affected.

 

 

INTRODUCTION:

Amniotic band syndrome is a broad term for a group of congenital abnormalities that occur when bands of amnion (the inner lining of the amniotic sack or "bag of water") peel away from the sack and attach or wrap around parts of the baby's body, disrupting normal development. The developing fetus floats in amniotic fluid in the mother's uterus. The fluid around the fetus and in the uterus is a sac. This sac has 2 layers which are stuck together: the outermost layer which lines the uterus is called the "chorion", and the layer closer to the fetus is called the "amnion". It is believed that amniotic band syndrome occurs when the inner membrane (amnion) ruptures, or tears, without injury to the outer membrane (chorion). The developing fetus is still floating in fluid but is then exposed to the floating tissue (bands) from the ruptured amnion. This floating tissue can become entangled around the fetus¹.

 

DEFINITION:

Amniotic band syndrome is a rare condition caused by strands of the amniotic sac that separate and entangle digits, limbs, or other parts of the fetus. This constriction can cause a variety of problems depending on where strands are located and how tightly they are wrapped¹.

 

Amniotic Band Syndrome – Alternative Names:

Some of these are different names for ABS and some are other syndromes that are often confused with ABS.  Misdiagnosis is apparently common.

·       Amniotic Deformity, Adhesions and Mutilations

·       Amniotic band disruption complex or sequence

·       Amniotic bands and sheets

·       Annular constriction bands

·       Congenital ring constriction

·       Constriction Band Syndrome and Amniotic Constriction Band Syndrome

·       Intrauterine amputation

·       Streeter’s dysplasia

·       TEARS (The Early Amnion Rupture Spectrum)

·       Congenital Transverse Defects or Deficiency

·       Limb-body Wall Complex²

 

Incidences:

The incidence of ABS is hard to determine because it is difficult to diagnose. The reported incidence varies from 1 in 1,200 to 1 in 15,000 live births. The incidence in miscarriages may be as high as 178 in 10,000².

 

CAUSES:

The most widely accepted theory of cause is the rupture of the amnion early in gestation, between 28 days after conception to 18 weeks gestation. The fibrous bands of amnion that result from this rupture can wrap around the limbs, resulting in tourniquet-like defects and amputations. This also can occur later in the pregnancy, but this is more commonly seen as the result of an amniocentesis or fetal surgery. When ABS occurs later in the pregnancy, it often has no effect on the baby³.

 

Effects of Amniotic Band Syndrome:

There are several features that are relatively consistent:

·       Syndactyly (webbed digits),

·       Distal ring constrictions,

·       Deformity of the nails,

·       Stunted growth of the small bones in the digits,

·       Limb length discrepancy,

·       Distal lymphedema (swelling), and

·       Congenital band indentations.

·       If a band wraps tightly around a limb, the limb can actually be completely amputated.

·       If the band is across the baby’s face it can cause cleft palate.

·       In a large number of cases the baby is also born with clubfeet.

·       ABS is also the cause of numerous miscarriages, such as when a band becomes wrapped around the umbilical cord⁴.

 

Prenatal Diagnosis of Amniotic Band Syndrome

The earliest detection of ABS by ultrasound has been at approximately 12 weeks gestation Treatment Options³

 

Treatment:

Treatment depends on which body part the band was wrapped around and the severity of the abnormality it caused.

·       In Utero Surgery – has been performed to free limbs from amniotic bands that threaten to amputate limbs.

·       Treating Syndactyly – it is plastic surgeries to separate his webbed fingers. A

·       Treatment of Congenital Amputation – The War Amps has a great program called Matching Mothers to connect families with similar amputations.

·       3D Printing of Prosthetics -Nia Technologies is a Canadian not-for-profit organization using 3D Printing to improve the lives of individuals living in the developing world.

·       Growing Hands -Distraction Augmentation Manoplasty – The technique pioneered by Dr. Cowen “grows” up to one inch of bone per month to create palms and lengthen fingers. A strange looking contraption of steel rods, pins, and screws is inserted through the existing bone. Screws are turned at an even rate several times a day to achieve growth of up to one millimeter a day. Turning the screws takes up slack and the body responds to this stress by growing bone.

·       Treating Cleft Lip and Palate

·       Treating Stabismus

·       Treating Clubfoot⁵

 

Prevention:

Amniotic band syndrome is considered an accidental event and it does not appear to be genetic or hereditary, so the likelihood of it occurring in another pregnancy is remote. The cause of amnion tearing is unknown and as such there are no known preventative measures³.

 

Prognosis:

The prognosis depends on the location and severity of the constricting bands. Every case is different and multiple bands may be entangled around the fetus. Bands which wrap around fingers and toes can result in syndactyly or amputations of the digits. In other instances, bands can wrap around limbs causing restriction of movement resulting in clubbed feet. In more severe cases, the bands can constrict the limb causing decreased blood supply and amputation. Amniotic bands can also sometimes attach to the face or neck causing deformities such as cleft lip and palate. If the bands become wrapped around the head or umbilical cord it can be life-threatening for the foetus. The number of cases of miscarriage that can be attributed to ABS is unknown, although it has been reported that it may be the cause of 178 in 10,000 miscarriages⁵.

 

REFERENCES:

1.      Do TT. Amniotic Band Syndrome (Streeter Dysplasia). Medscape Reference. August 22, 2016; http://emedicine.medscape.com/article/1260337-overview.

2.      Holmes LB. Amniotic Band Syndrome. NORD. 2015; https://rarediseases.org/rare-diseases/amniotic-band-syndrome/.

3.      Barros M, Gorgal G, Machado AP, Ramalho C, Matias A, Montenegro N. Revisiting Amniotic Band Sequence: A Wide Spectrum of Manifestations. Fetal Diagn Ther. 2014; 35:51-56. https://www.ncbi.nlm.nih.gov/pubmed/24247024.

4.      Seeds, et al. Br Med J (Clin Res Ed) 1983 Mar 19; 286(6369):919–920. 1982. [PMC free article][Pub Med]

5.      Bamforth JS. Amniotic band sequence: Streeter hypothesis revisited. Am J Med Genet. 1992; 44:280–287. [Pub Med]

 

 

Received on 21.11.2018          Modified on 18.01.2019

Accepted on 31.03.2019     © A&V Publications all right reserved