1. Conjoined Twins FAQ Prepared by Dr. Tarek A. Abd El Latif CMEC,Manager
EMS

2. What are conjoined twins?
Conjoined twins are monozygotic multiples that do not fully separate from each other due to the incomplete division of the fertilized ovum.
The individuals will be connected at certain points of the body, and may share tissue, organs or limbs.

3. Conjoined Twins How does it happen?
Monozygotic - also known as identical - twins form when a single fertilized ovum splits into two embryos.
This split can happen anytime after fertilization; as more time passes, the twins are more likely to share commonalities.
If the split occurs more than twelve days post conception, the embryos do not fully divide and the twins may share body parts.

4. Conjoined Twins How does it happen
Like all Monozygotic twins, conjoined twins are always same sex (either both boys or both girls).
It's a fairly rare occurrence.
Exact statistics are not known, but are estimated to be about 1 in 85,000 births.
About 1 in 200 sets of identical twins are born conjoined.
It is estimated that seventy percent of conjoined twins are female.

5. Conjoined Twins What are Siamese Twins?
Famed twins, chang and Eng Bunker, were born in Siam (now Thailand) in the early 1800's, although they eventually settled in the United States.
As they traveled the world, they became known as "the Siamese twins."
While they were the first conjoined twins whose medical history was documented, they were not the first conjoined twins.
Records reference a set of conjoined boys living in Constantinople in 945 A.D.
Another well-known set, Mary and Eliza Chulkhurst, lived in England in the twelth century.

6. Conjoined Twins What are the types of conjoined twins?
Conjoined twins are usually classified by the point at which they are joined (the Greek word pagos , meaning "that which is fixed.") .
There have been as many as three dozen separate types identified in the last century. The following basic classifications can be combined to more closely define individual cases.

7. Conjoined Twins What are the types of conjoined twins?
Those three dozen separate types are:
Conjunction never involving heart or umbilicus
Conjunctions Always involving the Umbilicus (Midline Conjunctions)
Rare forms of conjoined twins, having different patterns.

8. Conjoined Twins What are the types of conjoined twins?
Those three dozen separate types are:
Conjunction never involving heart or umbilicus
Conjunctions Always involving the Umbilicus (Midline Conjunctions)
Rare forms of conjoined twins, having different patterns.

9. Conjoined Twins What are the types of conjoined twins?
Conjunction never involving heart or umbilicus:
I- Craniopagus.
- Cranial union only.
- 2% of all conjoined twins.
II- Pygopagus.
Posterior union of the rump
19% of all conjoined twins.

10. Conjoined Twins What are the types of conjoined twins?
2. Conjunctions Always involving the Umbilicus (Midline Conjunctions)
I- Thoracopagus
II- Cephalopagus
III- Parapagus
IV- Ischopagus
V- Omphalopagus

11. Conjoined Twins What are the types of conjoined twins?
2. Conjunctions Always involving the Umbilicus (Midline Conjunctions)
I- Thoracopagus:
Anterior union of the upper half of the trunk.
They are the most common form of conjoined twins (about 35%).
It always involves sharing the heart.

12. Conjoined Twins - What are the types of conjoined twins?
2. Conjunctions Always involving the Umbilicus (Midline Conjunctions) .
II- Cephalopagus:
Anterior union of the upper half of the body with two faces on opposite sides of a conjoined head.
Extremely rare.
The heart is sometimes involved.
A combination of types I and II is called cepholothoracopagus.
skeleton of cephalothoracopagus twins delivered in Philadelphia in This skeleton has four feet.

13. Skeleton of parapagus twins, showing fusion of the lower half.
Conjoined Twins
What are the types of conjoined twins?
2. Conjunctions Always involving the Umbilicus (Midline Conjunctions) .
III- Parapagus:
Lateral union of the lower half, extending variable distances upward.
Sometimes called diprosopus.
about 5% of all conjoined twins.
Heart sometimes involved.
Skeleton of parapagus twins, showing fusion of the lower half.

14. Death cast of ischiopagus conjoined twins
What are the types of conjoined twins?
2. Conjunctions Always involving the Umbilicus (Midline Conjunctions) .
IV- Ischopagus:
- Anterior union of the lower half of the body.
6% of all conjoined twins.
Heart is not involved.
V- Omphalopagus:
- Anterior union of the midtrunk.
- 30% of all conjoined twins.
Death cast of ischiopagus conjoined twins
who died at age 13 months, in November , 1871.

15. Conjoined Twins What are the types of conjoined twins?
3. Rare forms of conjoined twins, having different patterns:
I- Parasitic twins.
- Asymmetrical conjoined twins, one twin being small, less formed, and dependent upon the other.
II- Fetus in fetu.

16. Conjoined Twins What is the prognosis for conjoined twins?
The prognosis depends on how the twins are connected.
It is estimated that 40-60% are born stillborn. 35% survive 24 hours or less.
For those that do survive, their parents will face difficult decisions regarding their future.
Some conjoined twins live successful lives despite the unique challenges they face.
Others are plagued by medical complications due to shared organs and vital systems.
Others are candidates for surgical separation.

17. Conjoined Twins How are conjoined twins separated?
Since the late twentieth century, many medical advances have resulted in the successful surgical separation of conjoined twins.
According to Nancy Segal in her book'"Entwined Lives," there have been approximately 200 attempted surgical separations of conjoined twins.
Three-quarters of the procedures since 1950 have resulted in one or both of the twins surviving.

18. Conjoined Twins
What are the risks involved with surgical separating adult conjoined twins?
In general, the greatest risks to conjoined twins during and after separation are anesthesia and surgical complications.
During surgery, both twins receive anesthesia using two separate sets of equipment.
Surgical complications can include formation of blood clots in the newly constructed blood vessels, intracranial bleeding, heart complications and infection.
The critical period is three to four days after surgery.

19. THANK YOU
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