Despite the limitations indicated to additive manufacturing―delayed printing time, a debatable fact according to the authors; high initial cost and of the creation processes, also quickly recoverable according to the authors; as well as the limitation of materials¹⁰; to which copyright infringement and harmful use, such as the manufacture of firearms, can be added―, this technology is an economical and sustainable solution, but beyond that, it guarantees the independence of the industry^1,2, basically in times of supply crises as in the case of the post-pandemics. Among its benefits should be mentioned^11,12:

• Manufacturing speed. Reduce production times by up to 90%. This makes it possible to intensify the manufacturing pace and reduce the cost of each part;

• Production on demand. This manufacturing model allows for smaller-scale and tailored runs, maintaining profitability at all times;

• Reductions of costs due to the fact that the digital processes of additive manufacturing also have an impact on storage and logistics costs. With this solution, a virtual stock is available and each piece is manufactured on the spot. In addition, the printers and materials used are getting cheaper;

• Energy saving. Digitally fabricated parts are much lighter. That is why this type of production requires less energy to operate and consumption is significantly reduced;

• Sustainability. It provides a cleaner and more respectful production with the environment. It also provides a reduction in both energy consumption and transport costs. It also benefits the logistical apparatus since the raw material occupies less space than the pieces themselves and, by betting on local production, dependence on those furthest away producers is eliminated.

Replicas of human body sections [trachea (figure 1) and bones], were obtained, which preserve the proportions and morphological veracity―the color depends on the color of the material used―, without the possibility of decomposition or contamination. This solution allows access to the anatomy avoiding availability, biosecurity, cultural and religious problems, without detrimental of teaching, by having an exact replica, which avoids the bias of models previously manufactured as teaching aids. In addition, it shows that it is possible to create a file or atlas of three-dimensional images obtained by surface scanner or CT. Likewise, tests on animal models, mannequins or cadavers are eliminated. It directly and positively impacts the teaching-learning process and the economy of this process in terms of the acquisition, creation and maintenance of conservation, storage and biosafety conditions.

Although for the development of curricular competencies in bronchoscopy there are low and high fidelity (virtual) simulators, each one with its advantages and disadvantages^13,14, these authors agree with Gando¹³ in the sense that 3D printing technology, in addition to being easily available since it does not have to be shared with other specialties, allows the creation of simulation models with greater realism and new pathological situations that cannot be reproduced in low-fidelity models, but with the advantages of this method: its low cost and high availability. And, on the other hand, the same for bronchoscopy as for surgical planning, the simulators manufactured by 3D printing outperform the virtual format in that they give the possibility of analyzing the piece in its real size, adding spatial and tactile dimensions.

In the case of the trachea, and since it was only intended to demonstrate its preprint processing, the authors worked with the region of interest from which only the trachea and main bronchi were obtained. If it were enlarged, more branches of the bronchial tree would be obtained, which would facilitate anatomical learning and endoscopic orientation.

Coinciding with de Frutos Marcos et al.¹⁵ the impression of the model for surgical repair in a case of craniosynostosis and from it, the planning of surgery, improved the surgeon's ability to clearly differentiate the spatial relationship of the anatomy and adjacent vital structures. It likewise improved the understanding of the scale, shape, and correct identification of the spatial geometry of affected bone structures. The intraoperative validation of the model confirmed the fidelity of its obtaining and the precision of the pre-surgical work. It had a positive impact on the outcome of the surgery and with it, impacts on the psychomotor development of the child.

Contrary to precise 3D printed and custom templates for intraoperative molding of implants in cranioplasty, manual molding, while feasible, does not always produce aesthetically pleasing results and may compromise concordance¹⁶. For this reason, a mold for a personalized cranial prosthesis was also designed and manufactured from DICOM images for a patient who suffered severe head trauma. Based on these images, a 3D printed model was obtained that served as a mold to create a personalized Subiton Surgical G implant, achieving adequate concordance and effective repair of the defect.

Mechanical hand prosthesis. Although an established trend points to the manufacture of myoelectrically controlled prostheses¹⁷, mechanical ones, working through a system of cables or harnesses, have the advantage of manufacturing time and the absence of complex components such as motors, batteries, electronic boards and sensors that are extremely expensive and difficult to obtain in different contexts. On the other hand, cosmetic prostheses would only aim to replace a member or part of it, taking into account its aesthetics rather than its functionality. Prostheses also contribute to tissue protection and psychomotor development in the case of children¹⁸. One of the development models was personalized according to the characteristics of the left hand of a male patient with a congenital malformation. This prosthesis allowed the patient to perform basic functions such as pincer and cylindrical grasp. Its implementation and use will improve the quality of life for specific patients¹⁹. This solution also has an economic impact due to the savings that non-importation represents knowing that the cost of a prosthetic arm―although really variable―, can be in the range of USD $5 000 for the simplest prosthetic arm and approximately USD $100 000 for a neuro-prosthetic model²⁰, however, those manufactured at CEFAS are significantly cheaper.

O₂ line splitters are devices that allow several patients to be connected to the same oxygen regulator, thus multiplying the possibility of using the available gas in patients with an indication of supplemental O₂. This solution was of great help in combating the health crisis experienced during the COVID-19 pandemic. It directly impacted by improving emergency care and avoiding the transit of patients to stages of greater respiratory compromise and deterioration of the general state, thereby reducing the human and economic cost that serious illness and intensive care represent.

Also, during the COVID-19 pandemic, there was a major shortage of masks and face shields. In collaboration with colleagues from Brazil, Canada and Germany, CEFAS manufactured protective masks that were donated to the Cuban health system in the midst of the health battle against the disease. It supplied the non-existence at a certain time, reduced the cost of its purchase and increased the security of the providers, improving care.

Of paramount importance for filling bone lesions are scaffolds for cell cultures. The function of a scaffold is to provide a biometric environment for cell attachment, proliferation, and secretion of extracellular matrix to replace or regenerate tissues, functionally and structurally^21,22. Several scaffolds, orthohedral and cylindrical, were built to order and in coordination with another scientific institution. Some were coated with calcium hydroxyapatite for biological testing.

A syringe holder model (figure 3) was designed and manufactured with ergonomic support, light material (and therefore lighter than traditional ones)―although with similar performance―, customized size, ambidextrous and significantly cheaper than models existing on the market. In addition to the marked economic impact, it has an impact on the improvement of diagnostic and therapeutic processes―related in the first instance, to the care of cancer patients―, also on the working conditions of the medical practitioner, morbidity and mortality and with all this, in health-care. Its unavailability hinders the interventional radiologist's freedom of action and definitively, the diagnostic or therapeutic procedure, according to the case. The tests showed the easy handling of the device. Although what really must be sterile is the syringe that will be used, the device is sterilizable. In the consultation of the state of the art carried out by the authors, a prototype like this had not been printed.

The first prototype of external breast prosthesis (figure 4) made by the authors, demonstrated the efficacy of the existing surface scanner at CEFAS given the inconvenience of obtaining images by tomography for these cases. With this, the algorithm of the process was established, which obeys the need to achieve personalized breast prostheses for mastectomized patients and to respond to the non-existence and discomfort manifested by carriers of prostheses that are marketed by standard sizes. Mastectomized women who can’t, or don’t want to have a breast implant would also benefit. The economic and psychological impacts―and with the latter, the improvement in the quality of life―are the most significant. In this case, the designs are obtained from anatomical data of the contralateral healthy breast, by three-dimensional mirror inversion scanning. Patients typically must obtain prostheses (imported, dependent on supply chains and financing) based on their size―which provides only minimal customization.

On the other hand, but also in relation to breast cancer, ignoring the variation of the breasts in volume, height, width, shape or orientation during the planning and execution of autologous reconstruction leads to undesirable results. To avoid this, custom breast molds that satisfy the requirements of both the patient and the cosmetic surgeon are created⁹. These facilitate understanding and interaction with the patient, as well as flap modeling. The results show more symmetry, high reconstructive quality, less surgical time is required, avoids or reduces the need for symmetrization in the healthy breast and generates savings for the institutions²³. According to Hummelink’s⁹ experience, these authors consider that it is necessary to increase the thickness of the mold developed, from 2 mm―thickness of the form―to 4 mm to provide greater resistance during its intraoperative use.

The results of this investigation, like other similar ones reported internationally^5-10, contribute directly, in a mediate or immediate way, to the solution of existing needs in the areas of intervention. These have a positive impact on the know-how of the institutions involved and on the sustainability of the health system due to their effect on costs, income, energy savings, decentralization of solutions and supply management, introduction of new practices or methods of work management and relations with other organizations; and likewise, in profitability, personalization, quality of care and satisfaction due to the faster incorporation into the working life of specific patients, the decrease in morbidity and the increase in the quality of life. On the other hand, in the medium term, they have an impact―also positive―, on the positioning of the solutions and the penetration of new markets. The positive preliminary results and the increasing accessibility due to the decrease in the costs of materials and equipment will contribute significantly to the exponential growth of 3D printing technologies in medicine. In the era of personalization and minimal invasion, its use anticipates a potential change in the resolution of complex conditions. With it, in short, a new paradigm is established.

As limitations of the study, access to data should be pointed out due to the absence of some specific medical conditions sub-records that prevent knowing the exact needs of the manufactures, the lack of previous studies carried out in our environment, at least published, that allow to substantiate the relevance of the research, and, finally, the manufacture of solutions and prototypes only in PLA.

The results of this work demonstrate the feasibility of using solutions manufactured by three-dimensional technologies for the practice and teaching of biomedical sciences in Matanzas, and show the need to develop them. It is therefore imperative that managers and the medical community in general, begin to become aware and accumulate experiences to guarantee its optimal use. Its development will improve healthcare with a significant reduction in costs, favoring local production and eliminating dependence on foreign producers.