Abstract
We have experience on thumb reconstruction using 3D printing technology in three main aspects. First, 3D printing technology improved accuracy in measuring the reconstructed thumb bone length. Second, we used mirroring technology to obtain the 3D image of normal shape of the injured thumb. Third, we used the bone segment model printed for accurate preoperative design and simulation of the operation. We also used models for preoperative communication. In future work, we plan to focus on the procedures and standardization of the 3D printing technology in thumb reconstruction. We intend to use 3D printing technology in the treatment of congenital hand malformations and to explore micro-3D technology.
Keywords::
3D printing technology has a wide range of medical applications, especially in surgery [Citation1]. However, there are few reports on 3D printing in hand surgery, and most of these have focused on thumb or finger reconstruction [Citation2–5]. For five, grade 3 thumb defects, our team used 3D printing technology to assist in the design of skeletal osteotomy before thumb reconstruction combining the wrap-around flap with the second toe. All five reconstructed thumbs survived, with function and appearance better than that achieved without 3D printing technology [Citation2], which achieved more than what we expected and made our team much pleased. We have experience in three main aspects of 3D printing technology.
First, during thumb reconstruction, it is critical to regain the normal length of the thumb. This depends on precise reconstruction of the skeletal length of the reconstructed thumb. After obtaining normal length data from the contralateral thumb, the accuracy of the 3D printing technology in measuring the reconstructed thumb bone length is unmatched by the past visual and ruler measurements. This improved accuracy, which is the first step in achieving good results.
Second, during the flap cutting, we used mirroring technology to obtain the 3D image of the normal shape of the injured thumb. Then, we overlaid the broken end of the thumb undergoing reconstruction with the 3D image. This technique allows the size of the deficient flap to be compared more accurately, with provided data for cutting the foot flap. Typically, the thumb is reconstructed with the surgeon looking at the healthy thumb in the process of surgery. However, this is very inconvenient when operating, and requires mentally transposing the reconstruction to the opposite thumb. In order to make the reconstructed thumb more realistic, we overlay a mirror image of the healthy thumb onto the image of the thumb undergoing reconstruction, and put the mirror image in computer, so that the surgeon can observe these at any time during the operation. This potentially provides guidance for suturing the flap and reconstructing the thumb. Our experience suggests that it is really helpful to observe the effect during operation.
Third, we used 3D printing technology to print out the bone segment model of thumb undergoing reconstruction. This is used for accurate preoperative design and simulation of the operation. This potentially avoids repeated intraoperative comparisons, saving operating time and improving the surgical outcomes. To study how to accurately cut the foot flap, Xu et al. [Citation5] printed 3D models of the deficient part of the thumbs and other fingers. Medical tape was then stuck on the models, cut to size and used to accurately guide the selection of the donor area. We did not use this tape technique in our surgery, but we would consider it in the future. In addition, we did use 3D printed models for preoperative communication. We displayed the models to the patients and their families when explaining the conditions and the operation plans. This helped the patients and their families to obtain a more intuitive understanding of their condition.
In our future work, we plan to focus on the procedures and standardization of the 3D printing technology in thumb reconstruction. We intend to investigate technical specifications, data collection standards and treatment process options, and to develop clinical pathways for application of 3D printing technology in thumb reconstruction.
As widely used in various fields of medicine, 3D printing technology, of course, can also be used in hand surgery, such as in the production of medical equipment, prosthetics and orthoses, in clinical teaching and in biological printing.
In the treatment of congenital hand malformations, we intend to use computed tomography and 3D technology to assist in the reconstruction of skeletal malformations. We also intend to use MRI and 3D technology to observe the variation of cartilage and articular surfaces for accurate correction of bone deformities.
We also intend to explore micro-3D technology, which is a potential future development of 3D technology. For example, an artificial peripheral nerve or a finger stent with biologically active cells could be printed in 3D. This would greatly advance hand surgery.
With further developments in material science, computer software simulation technology(e.g., the design and reconstruction of skin, nerves, blood vessels and joints), and manufacturing processes, 3D printing technology will serve the medical workers and patients better in the future.
Financial & competing interests disclosured
The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.
No writing assistance was utilized in the production of this manuscript.
References
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