SEPARATING CONJOINED TWINS

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SEPARATING CONJOINED TWINS

• David Tuggle MD

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History

• Pliny 70 AD
• maids of Biddenden, England
• Mary and Eliza Chalkhurst
• died age 34, 6 hours apart
• likely parapagus twins

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History

• Konig first recorded separation
• Ligated the liver bridge
• 1689 !

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History

• New world
• Johanna and Melchioraa
• July 18, 1533
• One soul or two?
• Joined at the liver, so they were thought to have
  two souls

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The Bunkers

• Eng and Chang bunker
• born in Thailand (then called Siam)
• Band of tissue 4.5 x 3.5 x 7.5 inches
• Liver and peritoneum

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Anatomy and Life

• Originally they faced each other
• Over time they stretched their connection
• PT Barnum
• Made a fortune
• Retired to Mount Airy, NC age 42
• Gentlemen of the south

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Bunker History

• Wives quarreled
• 19 to 24 children between them
• Fixed schedule of "visitation"
• Civil war destroyed their fortunes
• Back to show business until 1872

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Bunker history

• Chang had a stroke and they retired again
• Chang got pneumonia and died in the night
• Eng lived 2.5 hours longer then also died
• Autopsy showed a thin liver bridge, skin, and
  peritoneum
• No clear reason why Eng died, fear?

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Recent History

• 1988 O Neill
• 13 twin separations at one institution
• Prior to that 100 successful separations

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China vs OKC

• 7 cases in Shanghai from 1980 to 2005
• Shanghai Population- 20,000,000
• 2 cases in Oklahoma City from 1986 to 2009
• OKC Population- 2,000,000 !!!

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Frequency

• twins occur in 80-90 pregnancies
• 2/3 of twins are dizygotic, 1/3 monozygotic
• 1 in 40 monozygotic twinnings are incomplete
• about 1 in 50,000 births, stillborn rate is 60
• live born conjoined twins about 1 in 200,000
• females 31

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Twinning

• All monozygotic twinning occurs in the first week
• Incomplete division of the embryonic disc occurs
  in 2nd wk
• This early occurrence leads to wide variety of
  twinning and uniqueness
• Conjoined twins
• Parasitic twin
• Atypical conjoined twin
• Major early defects up to 20

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Types of Conjoined twins

• cephalopagus
• thoracopagus
• omphalopagus
• ischiopagus
• parapagus
• craniopagus
• rachipagus
• pygopagus

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Cephalopagus

• Top of the head to umbilicus
• 0.5 of CJT

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Thoracopagus

• Chest wall to abdomen
• Most often share a heart

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Omphalopagus

• Omphalopagus twins may share a liver,
  gastrointestinal or genitourinary functions, but
  rarely share a heart. Some Thorax

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Ischiopagus

• twins are joined at the pelvis. Many Ischiopagus
  share lower gastrointestinal tract, as well as
  the genital and urinary tract organs

Ischipagus tripus
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Parapagus

• Fused side-by-side with a shared pelvis. Twins
  that are dithoracic parapagus are fused at the
  abdomen and pelvis, but not the thorax. Twins
  that are diprosopic parapagus have one trunk and
  one head with two faces. Twins that are
  dicephalic parapagus have one trunk and two
  heads, and two (dibrachius), three (tribrachius),
  or four (tetrabrachius) arms

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Craniopagus

• Conjoined twins connected only at the head. They
  share bones of the skull and occasionally brain
  surface, separate trunks, four arms, four legs.
  About 2 of conjoined twins are craniopagus.

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Rachipagus

• Joined back to back at any point above the lumbar
  spine

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Pygopagus

• connected at the rump. Pygopagus twins, about
  19, have separate hearts but may share a spinal
  cord. There is one anus, two rectums, four arms
  and four legs

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Work Up

• identified prenatally
• fetal echocardiogram
• 10-20 associated congenital anomalies
• evaluate skin surface
• tissue expanders an option
• CT, heart echo, hida scan, barium ugi if needed
• angiography for evidence of shared circulation

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Things to think about

• treatment options
• stable or unstable
• 75 are thoracopagus or omphalopagus

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Immediately after birth

• Airway management
• Resuscitation
• ventilation
• IV access
• Separate teams even at birth

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Immediate treatment

• May need emergency separation
• May need Ex Utero intrapartum (EXIT) delivery

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Work up post delivery

• One heart or two
• Can the two hearts be separated?
• One QRS or two?
• Echocardiograms
• Cardiac catheterization

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Pulmonary- thoracopagus

• Shunts
• Chest deformity
• Scoliosis/posture
• Shared thoracic cavity
• Pulmonary hypertension

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Abdominal Workup

• Liver
• Biliary
• Gastrointestinal
• Genitourinary

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Ethics

• Should they be separated?
• Quality of life
• Will one be sacrificed to save the other?
• Societal values, legal issues, institution
• Wishes of the parents
• Control the media

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Timing

• Timing is not set in stone
• Immediate to 12 months
• Greater than 12 months separation anxiety
• Differential growth
• Cross over circulation

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Anesthesia

• Complex
• Cross circulation
• IV access for each
• Anatomy governs the monitoring, access, and
  anesthetic deliver

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Outcomes

• Craniopagus and thoracopagus worst
• Ischiopagus and pygopagus have best results
• Long term follow up crucial
• Often a need for follow up surgery