The technologies behind the operation to separate conjoined twins

About a month ago, a unique surgery to separate head-conjoined twins was performed at the Soroka-University Medical Center in Beer-Sheva, Israel. The twins that were born at Soroka in August 2020, jointed at the occipital part of their heads. This condition cause them to be almost handicapped, preventing them from freely move their body, crawl and normally developed.

An operation aimed to separate head-conjoined twins (medically called Craniopagus Twins) is considered highly rare and complex, and as of today – only 20 operations of this kind has been carried out. In this specific case, additional level of complexity was added, as some of the blood vessels at their cerebral cortex were coiled in each other, and some were even been used by both twins. In order to overcome this challenge, the medical team had to perform a detailed, precise mapping of the interfacing points between the babies.

CAD files of the brain

Mickey Gideon: “This case is about twins, conjoined not only with their head, but also with the Craniospinal compartment, the meninges and brain blood vessels. The main challenge was to understand which blood vessels are important to which twin – and to preserve them”. The learning and mapping processes were based on two types of three dimensional models: a physical one, printed with a 3D printer, and a virtual model – created by virtual reality (VR) technology. Both models were based on images from MRI, CT and angiography scans that simulated the complexity of the connection of the blood vessels, meninges, skull bones and skin of the twins. “Technology had central role in this operation. It provided us with the ability to merge the data and build 3D models which, in turn, enabled us to see the interface between the twins”.

The physical 3D model was built using 3D4OP technology and a 3D-Printer manufactured by Stratasys. 3D4OP was established and managed by Limor Haviv. This company developed technology to support the process of operation planning, using CT and MRI imaging to build a detailed CAD model of the target area, to include exporting CAD files in order to later print the models from polymer. This technology also supports the planning and printing of orthopedic transplants and even designated facilities tailor-made for a single patient. Those virtual models were transferred to medical printer developed by Stratasys, using polymer materials mimic the physical characteristics of tissues such as skin, bones, muscles, blood vessels etc.

The doctors used the physical models to plan the process of the surgery, and furthermore: they used it to practice their actions such as drilling and cutting. In parallel, the doctors were assisted in the virtual model created by Surgical Theater’s technology. This technology utilizes VR algorithms to construct a virtual model of the area based on CT and MRI imaging. This model provides the capability of better planning the procedure in a VR environment, where the users can enlarge specific areas, change watching angles and achieve clear insights regarding critical aspects such as optimal position and order of activities.  

Watch: The virtual model created by Surgical Theator:


Technology and medicine should cooperate

The model created by Surgical Theater’s technology made it possible for the surgeons to exactly map the routes of the coiled blood vessels in the interface area between the twins, something that otherwise was impossible to be achieved using standard imaging technologies. This virtual model was even in use during the operation itself, assisting them to navigate precisely within the joint area.

Gideon: “Using the virtual model we were able to observe the blood vessels from various angles, plan the procedure ahead and train ourselves in a VR environment. For instance – by using this VR technology we came to the decision that the procedure should begin when the twins are lying on their back”.

“The Israeli technology companies are groundbreakers, and the cooperation between them and the doctors should be tightened. Currently, we experience some break between these worlds. It is important for the companies to consult the doctors early in the requirement characterization, development and proof of concept phases. As the final users – joining the doctors with the processes will assist in deploying these technologies in the operating rooms.