Development of low-cost and personalized external silicone breast prosthesis produced by additive manufacturing for women who have undergone mastectomy: A pilot study.

BACKGROUND: The aim of this study was to develop a low-cost and personalized method for external breast prosthesis production. METHODS: The projected light method was used for the acquisition of the 3D geometry of the left breast of a healthy 29-year-old woman, 69 kg and 1.69 m. The 3D modeling software Blender was used to make the prosthesis model and mold with adjustments to the model's mesh, such as smoothing, assigning thickness, and creating the walls of the prosthesis mold. Two counter-molds were created. The pieces were manufactured on the 3D printer Stella Lite 3 using polylactic acid filament. Finally, the silicone was pigmented, and the mold was filled. FINDINGS: Prototype 1 of the prosthesis was produced using a mold without a counter-mold, which resulted in a prosthesis of 495 g, considered heavy compared to traditional prostheses for the same breast size. To solve this issue, a counter-mold with pins was used to produce prototype 2 with a mass of 393 g, 20.6% lighter than prototype 1. Prototype 3 was made with a central-volume counter-mold and presented a mass of 355 g, a reduction of 28.3% compared to prototype 1. The definitive breast prosthesis was made with the pin counter-mold with a different silicone. It has nipple and areola pigmentation and a mass of 294 g, 25.2% lighter than prototype 2. INTERPRETATION: The results suggest that the projected light method and additive manufacturing are potential tools for developing external breast prostheses, which may improve the health conditions and quality of life of mastectomized women.

A digital approach for design and fabrication by rapid prototyping of orthosis for developmental dysplasia of the hip

Abstract Introduction Immobilization in a hip spica cast is required in surgical and nonsurgical treatments for children aged three months to four years diagnosed with developmental dysplasia of the hip. Skin complications are associated with the use of the spica cast in 30% of the cases. This research explores the use of photogrammetry and rapid prototyping for the production of a lighter, shower friendly and hygienic hip orthosis that could replace the hip spica cast. Methods Digitalized data of a plastic dool was used for design and fabrication of a customised hip orthosis following four steps: 1) Digitalization of the external anatomical structure by photogrammetry using a smartphone and open source software; 2) Idealization and 3D modeling of the hip orthosis; 3) Rapid prototyping of a low cost orthosis in polymer polylact acid; 4) Evaluation tests. Results Photogrammetry provided a good 3D reconstruction of the dool's hip and legs. The manufacture method to produce the hip orthosis was accurate in fitting the hip orthosis to the contours of the doll. The orthosis could be easily placed on the doll ensuring mechanical strength to immobilize the region of the hip. Conclusion A new approach and the feasibility of both techniques for hip orthosis fabrication were described. It represents an exciting advance for the development of hip orthosis that could be used in orthopedics. To test the effectiveness of this orthosis for developmental dysplasia of the hip treatment in newborns, material and mechanical tests, design optimization and physical tests with patients should be carried.

Ex vivo evaluation of force data and tissue elasticity for robot-assisted FESS.

The objective of this study was to describe and evaluate soft tissue and bone properties of nasal cavity and paranasal sinuses in ex vivo preparations for a safe robot-assisted endoscope movement during functional endoscopic sinus surgery (FESS). In a first experiment we measured forces exerted by the endoscope during FESS with a force/torque sensor. In a second experiment we used a purpose built device to exert forces on chosen tissue structures. The experiment was monitored by a custom software, which records force of the endoscope and the deformation and the breaking point of tissue. All tests were performed on five formalin fixed cadaver heads. In the first experiment we found that the average force during FESS is 2.21 N and the maximal force is 7.96 N. The force-way-ratio measurement shows highest elasticity for the ethmoidal bulla, followed by the lamina papyracea; however, they break at low forces (> or =6 N). Furthermore the carotid canal seems to have the lowest elasticity but it can tolerate forces up to 30 N. Based on these measurements force thresholds can be defined for robot-assisted endoscope guidance. All thresholds have to be assigned to subregions of the nasal cavity and paranasal sinuses.