A chest wall is a protective cage formed by bones and tissues that surround vital organs such as the heart and lungs. Chest wall sarcomas arise from the spine, the sternum, and the ribs. Treatment for chest wall sarcomas can be difficult, as they often require surgery to remove the tumor. Extensive chest wall defects are caused by the resection of the chest wall after a wide local excision of the tumor. It is necessary to reconstruct both the skeletal and the soft tissues, and reconstruction has always been associated with higher mortality rates. Various technologies have evolved for the reconstruction of the chest wall and 3D implants are one of them.
What is a chest wall 3d implant?
Implants made with 3D technology to use in chest wall reconstruction are referred to as chest wall 3D implants. This technology has made it possible for implant manufacturers to develop complicated geometries that accurately resemble natural bone’s form and function and produce them in a shorter time [1].
How are 3d- chest implants developed?
The rapid development of individualized and patient-specific 3D chest implants has led to a new era in reconstructive surgery by precisely replicating the shape and structure of the chest wall to repair bony defects. It is essential that a chest wall defect covering material should be highly flexible, rigid, and stiff to prevent displacement, resistant to fracture, allow enough breathing activity, be biologically inert, and should even allow the adjacent tissues to grow.
Generally, the main materials used for 3D chest implants are titanium alloy powder, alumina ceramic molds, or surgical-grade solid silicone. In titanium 3D implantation, the framework is separated from the pleural cavity by a polytetrafluoroethylene plate to seal the operative area. It also prevents the development of pulmonary hernias. This plate will further reduce complications, accelerate rehabilitation, and improve patients’ quality of life with chest wall tumors.
An anatomical 3D model of the bony defect is created using information obtained from CT scan. Using computer-aided design (CAD) and mirroring technology, a customized prosthesis is designed and fabricated from titanium alloy powder or surgical-grade solid silicone. Several cycles are launched for building the individual layers of the product in a production process. As part of the printing process, layers of the 3D model of the product are divided into 20 to 100 microns thick to create a 2D image of each layer (section). The Selective Laser Melting (SLM) chamber of the machine is filled with argon (inert gas), which is used to build products [2].
Heat treatment is performed after construction to relieve internal stresses and improve mechanical properties. The mechanical properties of the printed prosthesis were further checked using an in-built software. The prosthesis is then separated from the platform, and finished with various machining processes. In the final stage of the manufacturing process, the implant is sterilized with ethylene oxide after it has been cleaned thoroughly [3].
What are the pros and cons of 3d implantation?
3D-printed implants are an effective tool for reconstructing the chest wall, notably for reducing operative time, less exposure to anesthesia, blood loss, and optimal restoration of function after surgery. Despite these advantages, 3D-printed implants also face some challenges that are listed below:
The lack of diversity of biomaterials is compounded by existing design and process constraints.
Even though implants are made from biomaterials, they can still trigger inflammatory reactions and lead to infection.
In addition, the sterilization of printed models is a common concern [4].
Replace, restore, and reconstruct!
Reconstruction is the most complicated and essential part, and replacement with an inappropriate prosthesis may result in repair failure. Compared to traditional prostheses, customized 3D implants can accurately restore the appearance and function of the missing part. Optimizing the design and fabrication process of a customized implant significantly affects its strength and effectiveness. If fabricated properly, these implants will restore the normal function and integrity of the replaced tissue and will improve the survival rate of chest wall sarcoma patients.
References
D. Balke, V. Gupta, and S. Welter, “Prospects of 3D-printed sternum prostheses: a review,” Journal of Visualized Surgery, vol. 6, no. 0, Art. no. 0, Jan. 2020, doi: 10.21037/jovs.2019.10.05.
S. J. Danker, A. F. Mericli, D. C. Rice, D. A. Santos, and C. E. Butler, “Custom 3D-printed Titanium Implant for Reconstruction of a Composite Chest and Abdominal Wall Defect,” Plast Reconstr Surg Glob Open, vol. 9, no. 11, p. e3885, Nov. 2021, doi: 10.1097/GOX.0000000000003885.
A. D. B. Ahmed, P. S. Prakash, and C. M. Li Cynthia, “Customized 3-dimensional printed rib plating in chest wall reconstruction,” JTCVS Tech, vol. 8, pp. 213–215, Apr. 2021, doi: 10.1016/j.xjtc.2021.04.015.
N. Martelli et al., “Advantages and disadvantages of 3-dimensional printing in surgery: A systematic review,” Surgery, vol. 159, no. 6, pp. 1485–1500, Jun. 2016, doi: 10.1016/j.surg.2015.12.017.
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