3-D Printing Saves Conjoined Twins

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Knatalye Hope and Adeline Faith Mata at Texas Children's Hospital. The conjoined twins underwent separation surgery when they were a little more than 10 months old. Texas Children's Hospital

Separating conjoined twins, which occur in one of every 200,000 live births, can be a high-risk procedure with an unknown prognosis. Irregular anatomy may mean siblings share organs, arteries and blood vessels. In those cases the surgery will then be life-threatening or lead to irreparable damage and disability in one or both of the babies. In the past, doctors would only have access to some of the most basic medical imaging to examine the nature of their connective anatomy and plan the operation before making any incisions.

But advances in medical imaging, mainly 3-D printing, may improve the safety and outcomes of separation surgery. A team of specialists at Texas Children's Hospital in Houston for the first time used advanced CT scans and 3-D modeling to map out the surgery of conjoined twins who were fused at the chest area all the way down to the pelvis. While the siblings each had their own heart (less common for conjoins with this type of fusion) they shared the same cavity for this vital organ. In initial scans, the team of doctors discovered a natural plane in the liver that would allow for separation.

The medical team, which presented the results of its case at a meeting for the Radiological Society of North America, began planning for the separation of Knatalye Hope and Adeline Faith Mata a year before the surgery when they were just less than 6 months old. The medical case required the expertise of 13 different specialities, with radiology being one of the most critical.

The team used data from the CT scans to create a color-coded plastic resin 3-D model of the skeletal anatomy. The organs were fashioned for rubber-like material. The livers were modeled from transparent resin with a map of blood vessels, which was critical to planning the surgery. The model, produced in about a week, is easily assembled and dissembled so the doctors could simulate a variety of procedures and techniques.

The twins underwent a successful surgery when they were just more than 10 months old. The procedure took 26 hours, 18 of which involved the actual separation.

Hospitals are increasingly interested in using 3-D printing during the planning stages of a variety of high-risk procedures. The problem, however, is that insurance companies don't currently cover the cost, even though the technology can vastly improve a patient's outcomes.

The 3-D model of the Mata twins is made from plastic resin and rubber. Texas Children's Hospital

Preliminary studies show 3-D modeling is typically anatomically correct, allows a surgeon to feel more confident when he or she enters the operating room and often results in more positive outcomes for patients. A systematic review of 36 studies on the use of 3-D modeling in surgery preparation (including cerebrovascular applications, neuro-oncology, functional neurosurgery, spine surgery and procedures involving catheter and endoscopic application), found prototyping anatomy of individual patients is useful and, in some instances, can be life-saving. Some hospitals also are now using the technology to prototype and produce custom surgical devices to address certain challenges of particular surgeries.