RIYADH: A London-based medical expert at a conference in Riyadh revealed the difficulties in separating a rare form of conjoined twins in which the patients are joined at the skull.

Dr. Felice D’Arco, consultant pediatric neurologist at Great Ormond Street Hospital in London, spoke during the International Conference on Conjoined Twins on Sunday about the condition, which occurs in about one of every 2.5 million births worldwide.

“Conjoined twins are rare, as has been said, but ‘cranomalies’ are extremely rare,” he said.

For radiologists, this means there are no standardized CT and MRI scanning protocols in place for such complex cases, and very few recent cases from which to learn.

“We have protocols for everything, epilepsy, tumors, neurogenetic disorders, this is not the case for craniopagus twins because of their rarity,” D’Arco said.

Medical teams must be set in place, and there must be two of everything; two anesthetic teams, two sets of MRI monitoring, etc., the whole hospital staff is involved in what is considered as an operation taking place on two patients simultaneously, D’Arco explained.

While there is a need to standardize procedures, Dr. D’Arco acknowledged that every set of twins is unique.

“As a radiologist, you need to have the flexibility to change your protocol as needed.”

Therefore, he said, it is best to start with a series of questions relating to different critical parts of the body.

One potential issue is the bones. A dual source CT scan can inform radiologists which parts of the skull of each patient is infused, or “missing,” in the other.

Another problem is the relationship between the brains. D’Arco said that small breaches connecting the two brains, identified by 3D sequencing, present a risk that surgery will cause damage.

Considering the possible ethical and medical complications that could come up in cases in which one of the twins is at risk of dying, he said: “Sometimes you need to ask, can we separate without jeopardizing the lives of the children? These cases are complicated, baffling, and confusing.”