Amniotic Band Constriction
Encyclopedia
Amniotic band constriction (also called amniotic band syndrome
(ABS), congenital constriction bands or rings, or ADAM (amniotic deformity, adhesions, and mutilations)) is a congenital disorder
caused by entrapment of fetal parts (usually a limb or digits) in fibrous amniotic bands while in utero.
A strong relationship between ABS and clubfoot exists. A 31.5% of associated clubfoot deformity and ABS can be correlated with 20% occurring bilaterally. Other abnormalities found with ABS include: lymphedema
, cleft lip, and/or cleft palate, and hemangioma
.
) ruptures without injury to the outer membrane (chorion
). Fibrous bands from the ruptured amnion float in the amniotic fluid
and can entangle the fetus, reducing blood supply and causing congenital abnormalities. In some cases a complete "natural" amputation of a digit(s) or limb may occur before birth or the digit(s) or limbs may be necrotic (dead) and require surgical amputation following birth.
In rare cases, if diagnosed in utero, fetal surgery
may be considered to save a limb which is in danger of amputation or other deformity. This typically would not be attempted if neither vital organs nor the umbilical cord are affected.
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 cleft palate. If the bands become wrapped around the head or umbilical cord
it can be life threatening for the fetus.
The number of cases of miscarriage that can be contributed to ABS is unknown, although it has been reported that it may be the cause of 178 in 10,000 miscarriages.
Amniotic band syndrome
Amniotic band syndrome is a congenital disorder caused by entrapment of fetal parts in fibrous amniotic bands while in utero.-Epidemiology:Amniotic banding affects approximately 1 in 1,200 live births...
(ABS), congenital constriction bands or rings, or ADAM (amniotic deformity, adhesions, and mutilations)) is a congenital disorder
Congenital disorder
A congenital disorder, or congenital disease, is a condition existing at birth and often before birth, or that develops during the first month of life , regardless of causation...
caused by entrapment of fetal parts (usually a limb or digits) in fibrous amniotic bands while in utero.
Epidemiology
Amniotic banding affects approximately 1 in 1200 live births. It is also believed to be the cause of 178 in 10,000 miscarriages. Up to 50% of cases have other congenital anomalies including cleft lip, cleft palate, and clubfoot deformity. Hand and finger anomalies occur in up to 80%.Features
The constriction of appendages by amniotic bands may result in:- Constriction rings around the digits, arms and legs
- Swelling of the extremities distal to the point of constriction
- Amputation of digits, arms and legs
A strong relationship between ABS and clubfoot exists. A 31.5% of associated clubfoot deformity and ABS can be correlated with 20% occurring bilaterally. Other abnormalities found with ABS include: lymphedema
Lymphedema
Lymphedema , also known as lymphatic obstruction, is a condition of localized fluid retention and tissue swelling caused by a compromised lymphatic system....
, cleft lip, and/or cleft palate, and hemangioma
Hemangioma
A hemangioma of infancy is a benign self-involuting tumor of endothelial cells, the cells that line blood vessels. It usually appears during the first weeks of life and sometimes resolves by age 10. In more severe case hemangioma may have permanency, if not treated by a physician...
.
Pathophysiology
ABS occurs when the inner fetal membrane (amnionAmnion
The amnion is a membrane building the amniotic sac that surrounds and protects an embryo. It is developed in reptiles, birds, and mammals, which are hence called “Amniota”; but not in amphibians and fish , which are consequently termed “Anamniota”. The primary role of this is the protection of the...
) ruptures without injury to the outer membrane (chorion
Chorion
The chorion is one of the membranes that exist during pregnancy between the developing fetus and mother. It is formed by extraembryonic mesoderm and the two layers of trophoblast and surrounds the embryo and other membranes...
). Fibrous bands from the ruptured amnion float in the amniotic fluid
Amniotic fluid
Amniotic fluid or liquor amnii is the nourishing and protecting liquid contained by the amniotic sac of a pregnant woman.- Development of amniotic fluid :...
and can entangle the fetus, reducing blood supply and causing congenital abnormalities. In some cases a complete "natural" amputation of a digit(s) or limb may occur before birth or the digit(s) or limbs may be necrotic (dead) and require surgical amputation following birth.
Diagnosis
Amniotic band constriction is often difficult to detect before birth as the individual strands are small and hard to see on ultrasound. Often the bands are detected indirectly because of the constrictions and swelling upon limbs, digits, etc. Misdiagnosis is also common so if there are any signs on amniotic bands further detailed ultrasound tests should be done to assess the severity.Treatment
Treatment usually occurs after birth and where plastic and reconstructive surgery is considered to treat the resulting deformity. Plastic surgery ranges from simple to complex depending on the extent of the deformity. Physical and occupational therapy may be needed long term.In rare cases, if diagnosed in utero, fetal surgery
Fetal surgery
Fetal surgery is any of a broad range of surgical techniques that are used to treat birth defects in fetuses who are still in the pregnant uterus.* Open fetal surgery involves completely opening the uterus to operate on the fetus....
may be considered to save a limb which is in danger of amputation or other deformity. This typically would not be attempted if neither vital organs nor the umbilical cord are affected.
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
Syndactyly
Syndactyly is a condition wherein two or more digits are fused together. It occurs normally in some mammals, such as the siamang and kangaroo, but is an unusual condition in humans.-Classification:...
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 cleft palate. If the bands become wrapped around the head or umbilical cord
Umbilical cord
In placental mammals, the umbilical cord is the connecting cord from the developing embryo or fetus to the placenta...
it can be life threatening for the fetus.
The number of cases of miscarriage that can be contributed to ABS is unknown, although it has been reported that it may be the cause of 178 in 10,000 miscarriages.
Prevention
Amniotic band constriction 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 measures.Literature
- Gabos PG. (Department of Orthopedic Surgery, Alfred I. duPont Hospital for Children, Wilmington, DE 19899, USA) Modified technique for the surgical treatment of congenital constriction bands of the arms and legs of infants and children Orthopedics. 2006 May;29(5):401-4
- Walter JH Jr, Goss LR, Lazzara AT. (Department of Orthopedics, Pennsylvania College of Podiatric Medicine, Philadelphia 19107, USA.) Amniotic band syndrome J Foot Ankle Surg. 1998 Jul-Aug;37(4):325-333
- Light TR, Ogden JA. (Dept. of Orthopaedic Surgery, Loyola University School of Medicine, Maywood, Illinois 60153, USA) Congenital constriction band syndrome. Pathophysiology and treatment Yale J Biol Med. 1993 May-Jun;66(3):143-155
- Further literature available e.g. via PubMedPubMedPubMed is a free database accessing primarily the MEDLINE database of references and abstracts on life sciences and biomedical topics. The United States National Library of Medicine at the National Institutes of Health maintains the database as part of the Entrez information retrieval system...
, free medical literature database of the US health authority (search for: amniotic band or congenital constriction bands or other synonyms) via http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed