Proceedings of the 2018 Design of Medical Devices Conference DMD2018 April 9-12, 2018, Minneapolis, MN, USA

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PREPARING FOR CONJOINED TWINS SEPARATION THROUGH VIRTUAL REALITY

Bethany Juhnke, MS Alex Mattson, BS Daniel Saltzman, MD, PhD Earl E. Bakken Medical Visible Heart Laboratory Department of Surgery Devices Center University of Minnesota University of Minnesota University of Minnesota Minneapolis, Minnesota, USA Minneapolis, Minnesota, USA Minneapolis, Minnesota, USA

Anthony Azakie, MD Eric Hoggard, MD Matthew Ambrose Department of Surgery Department of Radiology Department of Pediatrics University of Minnesota University of Minnesota University of Minnesota Minneapolis, Minnesota, USA Minneapolis, Minnesota, USA Minneapolis, Minnesota, USA

Arthur Erdman, PhD Paul Iaizzo, PhD Gwenyth Fischer, MD Earl E. Bakken Medical Visible Heart Laboratory Department of Pediatrics Devices Center University of Minnesota University of Minnesota University of Minnesota Minneapolis, Minnesota, USA Minneapolis, Minnesota, USA Minneapolis, Minnesota, USA

BACKGROUND Advances in technology are making virtual reality (VR) available BLUE RED for many different interests. Inexpensive commercially available Twin Twin hardware can be setup at home [1,2], while corporations are using VR to design mechanical systems and train pilots [3,4]. However, limited application is seen in the medical field. Most medical VR simulation focus on medical training, by incorporating anatomical models, physics models, haptics, and visualization to recreate surgical procedures [4-6]. These simulations teach foundational technical skills and show value for preoperative planning and image-guided surgery [4,7]. Simulations provide opportunities to develop surgical plans [7], and practice teamwork skills [8]. Studies have shown that expenses of implementing VR technology can be offset by reduced operating room time [5] and s can shape the operating room of the future [6]. Procedural planning using VR shows positive results for patient outcomes. One study looking at VR use for procedural planning found an increase in operational success, a decrease in 30-day mortality and Figure 1. The heart of the RED twin was completely developed with all four an estimated cost savings by incorporating 3D imaging [9]. A second chambers functioning properly and modeled as oxygenated (pink) and study saw increase confidence in 14 of 16 study participants when deoxygenated (purple) sides of the heart. The BLUE twin’s heart had three virtual reality rehearsals were used prior to the procedure [5]. chambers and therefore only one model was created (blue). Conjoined twins are very unique cases that require advanced planning to ensure the wellbeing of both patients. The separation of METHODS craniopagus conjoined twins in 1997 is the first record of using VR for Imaging. Individual computed tomography angiograms (CTA) preoperative separation planning [6]. The medical team used VIVIAN, were captured of each twin with contrast injected. The scans were a Dextroscope-based VR environment designed for . coded as RED baby and BLUE baby The twins were imaged at a The technology assisted with three craniopagus conjoined twins windowing level of 210, a window width of 1040 and slice thickness separations from 1997 to 2004 [6,10,11]. VR technology presented the of 600 μm. spatial relationships between anatomy and to simulate the Segmentation. Mimics [12] software was used to segment and techniques needed during the surgery [6]. analysis the twins anatomical data. The cardiac blood volume of the In summary, we present the first case to our knowledge of VR used contrast-injected twin, lungs and thoracic skeletal anatomy were to assist in the separation planning of thoraco-omphalopagus conjoined modeled for each twin. The red twin’s four-chamber heart was twins; a connection at the chest, that includes sharing a heart and may modeled as the oxygenated left side and the deoxygenated right side. also involve sharing their liver and digestive system.

1 Copyright © 2018 ASME The blue twin’s three-chamber heart remained as one model. Cardiac, immediately prompted the doctors to reconsider the orientation of the lungs and skeletal anatomies for each twin were aligned in the twins during the surgery. software 3-matic [13]. Initially, the cardiac anatomies were juxtaposed Accessing and stopping the flow between the twin’s hearts would by aligning the thoracic cage of the blue twin from each scan. be one of the first steps in the lengthy separation procedure. The After discussion with the clinical team, the constructed models surgical team decided to flip the orientation of the twins to have the were modified. Matching the hepatic venous vasculature across both blue twin on the left and the red twin on the right. This orientation the scan of the red baby and the blue baby realigned cardiac would allow for a smaller incision to ensure the twin’s stabilization

anatomies. This alignment represented a more accurate depiction of during the separation of blood flow between their two hearts. Downloaded from http://asmedigitalcollection.asme.org/BIOMED/proceedings-pdf/DMD2018/40789/V001T08A009/2787793/v001t08a009-dmd2018-6895.pdf by guest on 30 September 2021 the anatomy. The hypothesized communication between atria was revealed after alignment, joining the lateral right atrial protrusion of the blue twin to the right atrium of the red twin. INTERPRETATION Once both cardiac blood volumes were modeled, a surface Virtual reality provides opportunities to improve the surgical thickness around the blood volume was created and blood volume was planning process, particularly for complex pediatric and neonatal subtracted to create hollow models. The lungs and skeletons were operative procedures. Medical professionals can collaboratively plan modeled as solid models. The final models were exported as stereo procedures while visualizing the same anatomical reconstruction of a lithography files (STL). patient’s anatomy. Medical devices can be accurately sized to patients Visualization. The STL models were loaded into MeshLab [14] and necessary surgical adaptations can be explored prior to the and assigned colors. The models for the red twin were colored in warm procedure. colors; while the blue twin’s models were colored in cool colors. The Medical imaging algorithm advancements will increase the models were exported as object files (OBJ) with corresponding accessibility of these techniques for surgical planning. Additional material files (MTL). A scene file was created and loaded into the improvements in algorithms for visualization to analyze DICOM data stereoscopic display [15] available at the University of Minnesota, Earl will enable medical professionals to view patient-specific anatomical E. Bakken Medical Device Center. Active shutter glasses were used to models. Allowing for a translation of the information virtually to view the models, as a touch display could rotate, translate and hide provide remote surgical planning opportunities. models. Overall, these visualization technologies will decrease the cost of healthcare in the foreseeable future. Medical professionals will be able to make informed decisions about a patient’s diagnosis and care based RESULTS on patient specific anatomical visualization. Patients will receive more Members of the general surgery and teams accurate diagnoses in quicker timeframes to reduce the cost of each reviewed the anatomical visualizations. The first viewing confirmed individual’s overall healthcare, creating a more efficient and effective that the anatomy was segmented correctly. healthcare system. Atrial communication. The working clinical hypothesis was confirmed through the visualization that an atrial communication allowed free blood flow between the two hearts. This was evidenced REFERENCES by a close coupling of each twin’s p-wave as seen on EKG (i.e. one 1. Oculus Rift. https://www.oculus.com/rift/ twin’s atrial contraction was driven by the other twin’s atrial 2. HTC Vive. https://www.vive.com/us/ contraction), as well as increased plasma Brain Naturetic Peptide 3. Noon, C., Zhang, R., Winer, E., Oliver, J., Gilmore, B., & Duncan, (BNP) levels seen in the red twin. J. (2012). A system for rapid creation and assessment of Altering Surgical Planning. During the first viewing, members of conceptual large vehicle designs using immersive virtual reality. the surgical team discussed the best view of the anatomical models. Computers in Industry. 63(5):1-13. The teams preferred models that presented heart cavities surfaces. 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