Amniotic Band Syndrome

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Amniotic Band Syndrome ABS

• Dr Muhammad M El Hennawy
• Ob/gyn specialist
• 59 Street - Rass el barr dumyat - egypt
• www.drhennawy.8m.com

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What is Amniotic Band Syndrome?

• It is a set of congenital birth defects believed
  to be caused by entrapment of fetal parts
  (usually a limb or digits) in fibrous amniotic
  bands while in utero.

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Typs Of ABS

• A membrane formed at an early stage of
  pregnancy may cause severe damage to the
  structure of the various tissues, resulting in
  deformities in a large number of organs this
  often results in intrauterine death. Defects in
  these cases usually include defects in the
  location and structure of the heart, omphalocele,
  gastroschisis, anencephalus, cleft face,
  hydrocephalus, etc. A membrane formed at a
  later stage of pregnancy may not cause damage,
  but if it does, this is usually to limbs. The
  entire limb, part of it, or only digits can be
  involved, and the result can be limb stumps or
  scars in one or more limbs. Often those fingers
  that are not missing in the limb involved have
  signs of scarring or fusion. Sometimes the
  damage is milder, manifesting as a localized
  annular narrowing at the site where the membrane
  entrapped the limb, with swelling distal to the
  ring due to lymphedema.

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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 Complex 
• Amniotic deformity adhesions mutilations (ADAM).
• ADAM Complex
• Amniotic band sequence,
• Amniochorionic mesoblastic fibrous strings
• Congenital amputation,
• Congenital constricting bands

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Incidence

• Amniotic band syndrome (ABS) is an uncommon fetal
  malformation with increasing prevalence
• Amniotic banding affects approximately 1 in 1,200
  to 1 in 15,000 live births.
• It is also believed to be the cause of about 178
  in 10,000 miscarriages.
• About 80 of cases involve the hands and fingers
  and a significant number of clubfoot cases are
  correlated with ABS

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Prenatal risk factors

• No distinct sex predilection has been determined.
• Nearly sixty percent of the cases have some sort
  of abnormal gestation history.
• Prenatal risk factors associated with amniotic
  band syndrome include prematurity (lt37 weeks),
  low birth weight (lt2500 g), maternal illness
  (during pregnancy), maternal drug exposure and
  maternal hemorrhage/trauma.

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Causes

• Amniotic Band Syndrome is not genetic (i.e. not
  inherited).
• It is extremely unlikely that ABS will affect a
  future pregnancy. 
• To date, no prenatal factors have been associated
  with ABS
• The primary event is a rupture of the amniotic
  membrane and its detachment from the chorion with
  amniotic fluid leaking through the tear
  (spontaneously or after trauma to the lower
  abdomen ).
• As a result, the fetus can move digits or limbs
  through this tear and exit the amniotic cavity
  (partially or completely).
• The outer surface of the amnion, and to a lesser
  degree the naked chorion, produce mesodermic
  fibrous strings which may entangle and entrap
  different fetal organs, leading to constriction
  and amputation anomalies.
• These deductions agree with the increased
  frequency of constriction bands located more
  distally on the digits, hands and feet, as well
  as with the varying severity of constrictions,
  ranging from slight grooves in the skin to actual
  amputation of the digit or limb
• However, this theory does not explain the
  association of amniotic bands with damage to
  internal organs and other severe anomalies.

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The Timing Of The Rupture

• The timing of the rupture is believed to occur
  between 28 days after conception to 18 weeks of
  gestation.
• Late bands can occur and present at birth, even
  after a normal ultrasound was performed earlier
  in the pregnancy.

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Features or Stages

• The constriction of appendages by amniotic bands
  may result in
• Restrictions of the growth around the digits,
  arms and legs
• Constriction rings around the digits, arms and
  legs - the bands will partially constrict the
  blood flow in the affected appendage causing a
  deep groove in the baby's skin
• Swelling of the extremities distal to the point
  of constriction (congenital lymphedema)
• Amputation of digits, arms and legs (congenital
  amputation)

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Range of effects

• The defect could be merely cosmetic, depending on
  the severity of the constriction.
• Deeper bands may cause lymphatic obstruction
  leading to edema and vascular compromise,
  conditions that require immediate release.
• Abnormalities may occur distal to the
  constriction, such as anterolateral bowing,
  hemihypertrophy, pseudarthrosis, leg-length
  discrepancy, and teratologic clubfeet. These
  conditions may lead to limited function and
  movement.
• Early in gestation, spontaneous abortions may
  result from the encircling bands. If the
  constriction occurs after development is almost
  complete, fissures, acrosyndactylization, or
  intrauterine amputation occur typically on the
  extremities.

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• ABS affects the hands in almost 90 of cases. The
  distal portion of the extremities is most often
  involved, especially in the longer central
  fingers of the hand. The thumb and small finger
  are rarely involved, presumably because of their
  shorter lengths. In the feet, constricting bands
  most commonly involve the big toe (hallux).
• Lymphatic and vascular compromise may result from
  severe band compression. Immediate surgical
  release is required if at birth the child
  presents with a swollen, engorged digit or limb.
• More often, the constricted digit or limb has
  been amputated in utero. Acrosyndactyly occurs
  after digital separation is complete, but the
  fingers get twisted by bands and eventually join
  together.

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• Clubfoot occurs in up to 25 of cases of amniotic
  banding. In half of occurrences of clubfoot, a
  tight band wraps around the peroneal nerve, which
  causes muscle imbalance and clubfoot.
• Constriction bands across the face and head may
  result in facial clefts. Cleft lip and palate
  require reconstruction when the child is
  approximately 3 to 6 months of age.

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• ABS may affect the face with cleft lip or palate,
  asymmetric microphthalmia or severe nasal
  deformity. Encephalocele may be a manifestation
  of Amniotic Band Syndrome / ABS, especially when
  eccentrically placed off the midline.
• Abdominal wall defects - typically large defects
  with free-floating intestine but large enough for
  the lines to herniate outside the abdomen, can
  also be the result of Amniotic Band Syndrome /
  ABS.
• The characteristic appearance of an aberrant
  sheet or band of amnion attached to the fetus
  with resultant deformity and restriction of
  motion allows a diagnosis of Amniotic Band
  Syndrome / ABS to be made. Prenatal diagnosis is
  the exception rather than the rule.

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• The findings in Amniotic Band Syndrome / ABS may
  be limited to isolated defects, including
  isolated facial cleft, digital amputation or mild
  elephantiasis of an extremity beyond a
  constrictive band. These features may be
  difficult to diagnose using ultrasound because
  the detailed fetal visualization required is
  beyond the scope of routine obstetrical
  ultrasound examinations.
• At the worst end of the spectrum, the fetus may
  be so severely deformed by the amniotic bands
  that the spine is contracted and organs are
  formed in perplexing and bizarre proportions. The
  head may be completely misshapen or absent.
• The bands responsible for these deformities are
  rarely seen and a presumptive diagnosis of
  Amniotic Band Syndrome / ABS is made based on the
  commonly associated deformities.

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• The spinal deformities in Amniotic Band Syndrome
  can be severe, manifesting as kyphotic lordosis
  or scoliosis as well as severe rotational
  abnormalities, even spinal amputation. While
  spinal deformity can be seen in other syndromes,
  severe spinal deformity should suggest Amniotic
  Band Syndrome / ABS.
• Spinal deformity associated with an
  abdominal-wall defect is particularly suggestive
  of Amniotic Band Syndrome.
• While the typical appearance of an omphalocele is
  possible, the more common defect is a large
  slash-like defect of both the thoracic and
  abdominal cavities with evisceration.

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• These defects are associated with exteriorized
  bowel, liver and sometimes heart without an
  enveloping membrane. When associated with limb
  abnormalities, this is characteristic of the
  limb-body-wall complex form of Amniotic Band
  Syndrome.
• Deformation of the calvarium is another group of
  anomalies characteristic of Amniotic Band
  Syndrome.
• If complete, the fetus may appear anencephalic.
  If partial, the fetus may appear to have an
  encephalocele.

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How is ABS diagnosed?

• ABS is very difficult to diagnose.
• Prenatal ultrasound may not be able to identify
  the bands as the individual strands are small and
  hard to see on ultrasound but only see the
  results of the fusion such as missing or deformed
  limbs.
• Misdiagnosis is also common, up to 70 of all
  amniotic bands seen on prenatal ultrasound
  disappear upon repeat ultrasound. If the
  ultrasound demonstrates amniotic bands with free
  fetal movement and lack of fetal attachment to
  the band, they are termed innocent amniotic bands
  and pose little risk to the fetus.
• 3D ultrasound and MRI can be used for more
  detailed and accurate diagnosis of bands and the
  resulting damage/danger to the fetus.

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DD Of Amniotic Sheetsfrom Amniotic Bands

• Amniotic sheets are the most common with an
  incidence of 0.6. They are thought to be caused
  by scarring inside the womb or 'senechiae' from
  previous operations, such as DC. As the
  membranes develop, they surround these sheets of
  scar tissue. Often they aren't seen until later
  on in pregnancy, presumably following rupture or
  compression by the growing baby. Amniotic sheets
  have been found to be associated with an
  increased risk of early labour.
• Amniotic bands are even less common, affecting 1
  in 1200 (0.08) of all pregnancies. They are
  fibrous strands of membrane stretching from the
  outer membrane surface into the amniotic cavity.
  They are thought to originate when the inner
  membranes (amnion) rupture without injury to the
  outer membrane (chorion). The ruptured amnion
  remains as a plaque or fragments into bands which
  stretch across the chorionic cavity. Amniotic
  bands are thought to happen spontaneously or in
  association with trauma to the abdomen. There has
  been the suggestion of a relationship between
  amniotic bands, limb shortening and early chorion
  villous sampling (CVS).

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Other Bands

• Other less common types of band-like appearing
  structures may also be observed on obstetric
  sonogram.
• These include chorio-amniotic separation (normal
  finding in the 1st trimester up to 16 weeks),
  velamentous cord insertion, uterine fusion
  abnormalities (bicornuate, septate uterus, etc.),
  and remaining membranes after demise of a twin.
• In these situations, correlation of ultrasound
  features with patient's clinical history can be
  useful.

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Approach to Evaluating Band-like Structures

• The following diagram can be utilized to aid
  diagnosis when a band-like structure is
  visualized in the uterus. The authors advise
  caution, however, as there may be some overlap of
  appearances in the different categories

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• Ultrasound Appearance Usually thin membrane-like
  strands criss-crossing the amniotic sac and
  attached to fetal body parts. (ABS)

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• First trimester transvaginal sonogram showing an
  interesting synechia
• Ultrasound AppearancesShelf-like thick band
  communicating along it's length with the uterine
  wall along it's length. In other words, a
  synechia has a base and a free edge. This
  appearance is caused by a combination of the
  fibrous synechia itself, and the complete
  wrapping of fetal membranes around the synechia.  

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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 measures.

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Interventions and 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 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.

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Fetal Treatment

• In utero limb salvage fetoscopic release of
  amniotic bands for threatened limb amputation.
• Fetoscopic laser release of amniotic bands in
  extremity ABS offers the potential to prevent
  limb amputation
• A small camera is inserted through the mothers
  abdomen and uterus into the amniotic sac in order
  to see and cut the bands.
• Cutting the amniotic bands is performed utilizing
  a fetoscopic technique.
• The procedure is typically performed under
  regional anesthesia.
• Early fetoscopic release may prevent amputation
  and allow improved limb development.

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Child Treatment

• Indications for intervention depend on the
  medical stability of the child and on the
  neurovascular status of the limb.
• Bands that only cosmetically affect the
  superficial skin generally do not require any
  intervention.
• Only the tight constriction bands, resulting in
  gross lymphedema, vascular compromise, or both
  necessitate immediate surgical release.
• Surgery also is indicated for patients with
  syndactyly or acrosyndactyly that compromises
  hand function. Thumb amputation (which is rare),
  club feet, cleft lip, and cleft palate require
  reconstruction, but these procedures can be
  performed electively at a later time.

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Special Considerations For Delivery

• Type of delivery - Typically, pregnancies with
  ABS do not require cesarean delivery. The need
  for fetal intervention should not impact the mode
  of delivery. The delivery plan will be carefully
  discussed.
• Place of delivery - If all the prenatal
  monitoring suggests that the baby is doing well,
  the baby can be delivered at the hospital.
  However, the hospital should be prepared to
  handle any immediate needs of the newborn and
  have a neonatal intensive care unit with the
  capability to provide specialized care.
• Time of delivery - Unless there are signs of
  serious complications of ABS, there is no reason
  to intentionally induce an early delivery. The
  team at the Center may recommend early delivery
  for pregnancies that appear to be in danger

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Follow-up and prognosis

• All patients with ABS should be monitored
  regularly until skeletal maturity is reached,
  because of the potential for recurrence of the
  rings and for secondary contractures that may
  develop
• The prognosis is good for limbs affected by
  isolated superficial extremity bands. Aside from
  cosmetic irregularities, no functional defects
  are usually present. Deeper bands may be
  associated with progressive problems leading to
  lymphatic and neurovascular compromise that
  requires operative intervention.
• For patients with acrosyndactyly, hand function
  is limited secondary to stiffness of the joints,
  but reconstruction can result in good prehension
  and grasp. Children whose limbs have been
  amputated in utero usually adapt well to their
  physical limitations, and aside from fitting with
  a prosthesis, little often needs to be done. In
  children with a transverse deficiency proximal to
  the ankle joint, a prosthesis is required for
  full function.

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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
  fetus.

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Acrosyndactyly

• Acrosyndactyly is a more complex type of
  syndactyly. The fingers had separated but a band
  formed around the fingers causing them to refuse
  during development.
• These images are the left and right hand of a
  newborn.

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Amputated Big Toe

• ABS is the most common cause of a congenital
  amputation of a limb/digit.

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Banded Foot

• When bands wrap around limbs during development
  they can constrict the limb causing decreased
  blood supply and amputation.

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Banding on Leg

• This image shows a banding line on newborn's leg.

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Cleft Lip Palate

• Oral clefting occurs when the tissues of the lip
  and/or palate of a fetus don't grow together
  early in pregnancy.
• Children with clefts often don't have enough
  tissue in their mouths, and the tissue they do
  have isn't fused together properly to form the
  roof of their mouths.

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• The umbilical cord of the dead twin is completely
  amputated.

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Clubfeet Photo

• A strong relationship between ABS and clubfoot
  exists.
• A 31.5 of associated clubfoot deformity and ABS
  can be correlated with 20 occurring bilaterally.

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Nubbins

• This is typical of Congenital Transverse
  Deficiency, a form of ABS.
• A short below-the-elbow amputation. The fingers
  may be represented only by nubbins or dimpling
  found on the end.

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Overlapping, Underlapping Toes

• Congenital Overlapping toes are characterized by
  one toe lying on top of an adjacent toe.
  Congenital Under lapping toes usually involve the
  fourth and fifth toes.

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Syndactyly - at birth

• A hand at birth, the banding line from the wrist
  to the pinky finger and around the wrist. The
  three fingers are webbed together (syndactyly).
• The three fingers are small, with abnormal finger
  nails, and missing some joints.
• There is also some lymphedema (swelling at the
  joint) of the index finger middle joint.

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• ABS affecting the leg above ankle.

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• Left hand with constriction bands, dystrophic
  nails and fusion of digits II-V by amniotic
  membrane.

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• Right foot with stunted growth of all digits,
  dystrophic nails, constriction bands and partial
  syndactyly of digits II to V.

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Clubfoot Treatment

• The accepted method of treating clubfeet is by
  the Ponseti method of Serial Plaster Casting.
  Treatment should be started right away. The
  initial treatment consists of manipulating the
  foot to get it to the best position possible, and
  then holding the correction in a cast.

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Syndactyly - Surgically Separated

• This photo is after two operations that separated
  his webbed fingers (syndactyly).

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Distraction Augmentation Manoplasty

• This surgery creates growth at the rate of an
  inch of bone a month, to create new palms and to
  lengthen the fingers. It consists of the
  insertion of a device through the bone which is a
  complex group of bars, nails and steel screws. It
  requires screwing several turns per day to reach
  a growth rate of up to 1 ml. daily.

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Summary

• Amniotic Band Syndrome can be difficult to
  diagnose. Ultrasound does not usually reveal it.
• Even though the incidence of the condition is
  very low, obstetricians need to be aware of the
  possibility of umbilical cord constriction by an
  amniotic band.
• The presentation of a patient with decreased
  fetal heart rate and a history of amniocentesis
  must to be monitored closely. There is a high
  fetal death rate associated with this diagnosis.
  When the fetus is at a viable gestational age,
  immediate delivery may be indicated.
• When Intrauterine Demise does occur, amniotic
  band syndrome should be included as one of the
  possible etiologies. Thorough evaluation of the
  placenta and cord is necessary to rule out
  constriction of the cord by Amniotic bands.
• Although the finding of Amniotic Band Syndrome
  may not change the outcome identifying a
  definitive cause for the parents may provide a
  small measure of closure in the context of this
  tragic event.