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Johns Hopkins Team Separates German Conjoined Twins

Johns Hopkins Medicine
Office of Corporate Communications
MEDIA CONTACT: Staci Vernick Goldberg
PHONE: (410) 516-4958
September 16, 2004

*Please note:  Photo information, fact sheets and audio is available at the bottom of this page.

Johns Hopkins Team Separates German Conjoined Twins
One twin succumbs to complications of surgery

Surgeons at the Johns Hopkins Children’s Center at 12:15 a.m. Thursday completed the separation of 13-month-old twins Lea and Tabea Block. Later in the morning, regrettably, Tabea Block died of major complications associated with the separation surgery. Lea remains stable, and is recovering in the Children’s Center’s pediatric intensive care unit (PICU).

The girls, from Lemgo, Germany, were born craniopagus, joined at the top of the head. Although their brains were separate and distinct, the two organs shared numerous important blood vessels including the superior sagittal sinus, the major blood drainage system of the brain. The risks of surgical separation were understood and carefully considered by the family and the medical team at Hopkins before a decision was made to proceed.

“I speak for the entire team in saying we are deeply saddened by Tabea’s passing,” said Benjamin Carson, M.D., director of pediatric neurosurgery at the Children’s Center. “I am proud to have been part of a tremendous, selfless and universal effort put forth by every member of this institution who cared for these girls and helped this family achieve their goal. And I am thankful for the courage of this family. We have high hopes for Lea, who now has a good chance at leading a healthy, independent life.”

Carson led a multi-disciplinary team in the surgery, which began at 7 a.m. on Saturday, Sept. 11 with the initial scalp incisions. By early afternoon, pediatric neurosurgeons opened the twins’ shared skull and began the painstaking process of teasing apart brain tissue and countless blood vessels. At approximately 8 p.m. that night, surgery was halted when one twin developed metabolic complications that caused her vital signs to become unstable.

With both twins stable and gaining strength later in the week, surgery resumed at approximately 6 a.m. Wednesday, Sept. 15. Surgeons proceeded with the most challenging part of the surgery – the separation of the tangle of blood vessels at the back of the head known as the dural venous complex. Several hours later, they completed surgical separation and the medical team broke into two groups, one for each twin. Color coding was used to easily identify the team assignments: the “yellow team” operated on Lea, and the “orange team” on Tabea. The moment of separation was at approximately 12:15 a.m. and all surgery ended at approximately 1:45 a.m.

In early June, the twins arrived at the Children’s Center for imaging studies and testing. Months of preparation began with a series of imaging studies, including angiogram, where a harmless dye injected through the femoral artery in the leg details the path of blood flow through the joined brains. This information is crucial for neurosurgeons who must determine which vessels should be routed to which twin. Combined with three-dimensional CT (computed tomography) and MRI (magnetic resonance imaging) images, the team studied a complete picture of the twins’ anatomy above the neck.

A 3-D Virtual Workbench integrated the twins’ angiogram, CT and MRI studies into a single hologram floating in the black space of a computer console. Using hand levers, surgeons were able to manipulate and study the images and, in essence, “practice” the surgery in advance. They also studied minutely detailed anatomical models built from the radiologic images so they’d have anatomical landmarks to reference during surgery.
Carson said the young age of the twins would be an important factor in the success of the operation, because young brains are still “plastic” and can more readily compensate for and recover from the trauma of surgery. He also cited technological advances in imaging techniques and surgical instruments that improve the likelihood of successful outcomes of such complex surgeries.

On June 9, the girls underwent surgery to insert tissue expanders beneath their scalps. During the summer, doctors periodically injected sterile fluid into the bladder-like expanders in order to stretch the skin of the girls’ scalps. This step was necessary to provide adequate skin to cover the openings in their skulls following separation.

Teams of neurosurgeons (17 individuals), plastic surgeons (five individuals), anesthesiologists (14 individuals), nurses (42 individuals), and medical and surgical technicians (22 individuals) rotated in shifts during the lengthy surgeries, with approximately 25 people in the OR at any given time. Numerous others contributed expertise and support, including: neuroradiologists, intensivists and Pediatric Intensive Care Unit (PICU) nurses, physician’s assistants and support personnel. In all, more than 150 Johns Hopkins employees were involved in the Block twin separation surgery.

Two members of the twins’ German medical team, neurologist Tilman Poster, M.D., and pediatrician Martin Bruns, M.D., traveled to Baltimore to help support the family with an understanding of the complex medical procedures and situations involved in separation surgery.

Lea Block will remain at Johns Hopkins Children’s Center for several weeks or months while doctors monitor her recovery. She will require future surgeries to reconstruct her skull and scalp. Upon discharge, she will return to Germany where she will be under the care of her German medical team.

“If there are no major complications, I fully expect Lea will grow into a strong young girl and will lead a normal, independent life,” Carson said.

Conjoined twins occur in every 70,000 to 100,000 live births. Craniopagus twins occur approximately once in every 2 million live births. They are considered the most difficult to separate.

Johns Hopkins Children’s Center surgeons have separated seven sets of conjoined twins since 1982. Most recently, in 2003, Director of Pediatric Surgery Paul Colombani, M.D., led a team that successfully separated 2-month-old Nigerian twin girls joined at the abdomen and sternum, and sharing one liver.


Editor’s Note: A medical illustration of the twins, detailing conjoined areas, and photos of the medical team can be found at

At the request of the Block family, no photos or film of the twins or the separation surgery is available to the media.