PD3D | Patient-Specific Medical Devices
16964
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Patient-Specific Medical Devices

About This Project

Medical devices and surgical tools are designed to fit a large percentage of patients and standard anatomy. If you do not fall within that percentage, the surgical team will be forced to improvise or make do with the available tools and instruments. The Prototype Development and 3D Print Lab (PD3D) at the University of Central Florida (UCF), with the support of Nemours Children’s Hospital and Stratasys Ltd. (world leader in 3D Print Technologies), plans to develop a process to quickly and efficiently design and produce medical devices tailored to the anatomy of the patient. The process aims to create devices suited to the anatomy and physiology of patients that do not fit the “average adult” or, most commonly, the “average child.” Our process will leverage 3D imaging, patient-specific 3D modeling, and additive manufacturing, with the long-term goal of mitigating risks, minimizing time, and diminishing costs of surgical procedures.

PATIENT-SPECIFIC 3D RECONSTRUCTIONS

In partnership with Nemours Children’s Hospital, we are generating 3D reconstructions based of patient-specific MRI and CT images. Faculty and students reconstruct patient-specific data using software platforms such as 3D Slicer [4]. Accuracy of the 3D reconstructions will be validated by radiologists and radiology technician at Nemours Children’s Hospital.

Reconstructions will form a 3D database of patient-specific anatomy that will be used for visualization, education, training, and future iterations of our process. With expertise in VR and AR, our team will create an interactive library for medical students, residents, and physicians. The anatomy database could also be used for statistical shape analysis [5, 6], a field of research that would allow our process to predict the anatomy of the patient based on a database of models. Research extensions like shape analysis could eliminate the need to perform MRI or CT, further reducing costs for the patients.

DEVICE DESIGN AND VALIDATION

Combining expertise in 3D modeling, engineering design, and material science, we are developing software capable of designing and optimizing devices to fit patient-specific 3D reconstructions. Throughout this effort, and looking into the future, optimizing will consider dimensions, motion, and device-tissue interaction. The initial version of our process will focus on using dimensions and volume of the patient’s airway to modify and optimize the design of the laryngoscope. Current laryngoscopes feature interchangeable blades that vary in curvature and length, the latter correlated to the age and size of the patient. It is standard practice to bring several blades when difficult intubations are expected [2]. Laryngoscopes optimized to the patient’s airway will reduce intubation time and risks.

Understanding the effects of motion and device-tissue interactions are essential for the evolution of our process. Throughout this effort, we will explore the creation of a framework to simulate the process of airway intubation, merging human and device. The framework will introduce the motions associated with intubation, which will affect airway dimensions and volume measurements. Device optimization will then be based on airway dimensions that change through time. The framework will also introduce the deformation caused by the interaction between device and tissue. Stress analysis of the intubation process will be used to further modify laryngoscope features that could cause damage to the patient [7]. In addition to superficial modifications, stress analysis could recommend more compliant materials for the manufacturing of the laryngoscopes. In addition to compliant materials, we could 3D print materials that generate the specific mechanical response recommended by the stress analysis. We have developed and patented a method for the design and manufacturing of composites with tunable physical properties, that could be used to achieve this goal [8].

FABRICATION

The long-term implementation of our process, within or near an OR, will require a 3D printer capable of non-stop manufacturing, with minimal to no user interaction and maintenance. Stratasys’ Continuous Build 3D Demonstrator (CB3D) was designed with these needs in mind [11]. Rather than a single system, Stratasys’ CB3D consist of a stack of three (3) printers connected over the cloud. The cloud allows interaction between stacks, creating a network of printers within a company or, in this case, within a hospital. In 2017, we became the second academic institution in the US to acquire a CB3D system for BETA testing. Since its installation, we have been responsible for evaluating the system, recommend improvements, and determine potential areas of application. Unlike regular printers, CB3D stacks assign jobs to available printers, calibrate, eject, and move on to the next job automatically. Connected to our process, CB3D stacks will print patient-specific laryngoscopes ahead of surgery. Each print labeled to avoid confusion.

In collaboration with Stratasys, we will print patient-specific laryngoscopes with FDA-approved, biocompatible, and sterilizable plastics [3]. We will work with Stratasys to bring these materials to the CB3D or a faster, more novel technology. Last April, Stratasys unveiled a spun-off Evolve Additive Solutions. The company’s “STEP” technology is capable of manufacturing fifty-times (50X) faster than current 3D printers. The technology is expected to reduce costs per part closer to those of traditional manufacturing [12]. We will work with Stratasys to gain access to the technology, currently unavailable to the market, for a case study production run of patient-specific laryngoscopes.

ACKNOWLEDGEMENTS

Patient-Specific Medical Devices would not be possible without the support of our sponsors and collaborators;

Stratasys
REFERENCES

[1] M. Weiss and T. Engelhardt, “Proposal for the management of the unexpected difficult pediatric airway,” Pediatric Anesthesia, no. 20, pp. 454-464, 2010.

[2] R. W. M. Walker and J. Ellwood, “The Management of difficult intubation in children,” Pediatric Anesthesia, no. 19, pp. 77-87, 2009.

[3] Stratasys, “ABS-M30i,” Stratasys, [Online]. Available: http://www.stratasys.com/materials/search/abs-m30i. [Accessed 22 August 2018].

[4] A. Fedorov, R. Beichel, J. Kalpathy-Cramer, J. Finet, J.-C. Fillion-Robin, S. Pujol, C. Bauer, D. Jennings, F. Fenessy, M. Sonka, J. Buatti, S. Aylward, J. V. Miller, S. Pieper and R. Kikinis, “3D Slicer as an image computing platform for the Quantitative Imaging Network,” Magnetic Resonance Imaging, no. 30, pp. 1323-1341, 2012.

[5] M. D. Harris, M. Datar, R. T. Whitaker, E. R. Jurrus, C. L. Peters and A. E. Anderson, “Statistical Shape Modeling of Cam Femoroacetabular Impingement,” Journal of Orthopaedic Research, vol. 30, pp. 1620-1626, 2013.

[6] K. B. Jones, M. Datar, S. Ravichandran, H. Jin, E. Jurrus, R. Whitaker and M. R. Capecchi, “Toward an Understanding of the Short Bone Phenotype Associated with Multiplet Osteochondromas,” Journal of Orthopaedic Research, no. 31, pp. 651-657, 2013.

[7] M. Carassiti, V. Biselli, S. Cecchini, R. Zanzonico, E. Schena, S. Silvestri and R. Cataldo, “Force and pressure distribution using Macintosh and GlideScope laryngoscopes in normal airway: an in vivo study,” Minerva Anestesiologica, vol. 79, no. 5, pp. 515-524, 2013.

[8] F. L. Lobo Fenoglietto and J. Stubbs, “Method for the design and manufacture of composites having tunable physical properties”. United States of America Patent 15/895,478, 13 February 2018.

[9] S. A. Maas, B. J. Ellis, G. A. Ateshian and J. A. Weiss, “FEBio: Finite Elements for Biomechanics,” Journal of Biomechanical Engineering, vol. 134, January 2012.

[10] M. K. Rausch, G. E. Karniadakis and J. D. Humphrey, “Modeling Soft Tissue Damage and Failure Using a Combined Particle/Continuum Approach,” Biomechanics and Modeling in Mechanobiology, vol. 16, no. 1, pp. 249-261, 2017.

[11] Stratasys, “Stratasys Demonstrates Innovative Multi-Cell Additive Manufacturing Platform Designed for Continuous Production,” Stratasys, 9 May 2017. [Online]. Available: http://investors.stratasys.com/news-releases/news-release-details/stratasys-demonstrates-innovative-multi-cell-additive. [Accessed 28 August 2018].

[12] Stratasys, “Stratasys Unveils Spin-off Evolve Additive Solutions to Focus on New “STEP” Technology,” Stratasys, 3 April 2018. [Online]. Available: http://investors.stratasys.com/news-releases/news-release-details/stratasys-unveils-spin-evolve-additive-solutions-focus-new-step. [Accessed 28 August 2018].

[13] Stratasys, “Stratasys J750,” 2017. [Online]. Available: http://www.stratasys.com/3d-printers/production-series/stratasys-j750. [Accessed 25 May 2017].

[14] J. S. Doherty, S. R. Froom and C. D. Gildersleve, “Pediatric laryngoscopes and intubation aids old and new,” Pediatric Anesthesia, no. 19, pp. 30-37, 2009.

Category
3D Printing, Medical, Modeling, Prototype