Three-dimensional printing in orthopedics: where we stand and where we are heading / Impressão 3d na ortopedia: onde estamos e aonde podemos chegar

ABSTRACT Three-dimensional printing is a technology in expansion in the medical field. It also presents many applications in orthopedics. Our review article aims to describe 3D printing, types of 3D printers, and its use in the orthopedic field. 3D models can be created using tomography scans. Those models can then be manipulated, even simulating surgeries. It is possible to print biomodels, which will help us understand deformities and plan surgeries. Orthopedic surgeons must be updated in these disruptive technologies that may help their daily practice. Level of Evidence V, Expert opinion.

RESUMO A impressão 3D é uma tecnologia em expansão na medicina, possuindo diversas utilidades na ortopedia. O objetivo deste artigo de revisão é descrever o que é a impressão 3D, seus tipos e suas aplicações na ortopedia. Modelos em 3 dimensões podem ser criados a partir da tomografia computadorizada. Estes modelos podem ser manipulados em softwares específicos, onde inclusive cirurgias podem ser simuladas. Utilizando impressoras 3D podemos criar biomodelos que nos ajudam a compreender deformidades e planejar cirurgias. É importante que o ortopedista se mantenha atualizado nestas novas tecnologias disruptivas que podem auxiliar muito no seu dia a dia. Nível de Evidência V, Opinião do especialista.

Otobone ®: Three-dimensional printed Temporal Bone Biomodel for Simulation of Surgical Procedures

Introduction: The anatomy of the temporal bone is complex due to the large number of structures and functions grouped in this small bone space, which do not exist in any other region in the human body. With the difficulty of obtaining anatomical parts and the increasing number of ear, nose and throat (ENT) doctors, there was a need to create alternatives as real as possible for training otologic surgeons. Objective: Developing a technique to produce temporal bone models that allow them to maintain the external and internal anatomical features faithful to the natural bone. Methods: For this study, we used a computed tomography (CT) scan of the temporal bones of a 30-year-old male patient, with no structural morphological changes or any other pathology detected in the examination, which was later sent to a 3D printer in order to produce a temporal bone biomodel. Results: After dissection, the lead author evaluated the plasticity of the part and its similarity in drilling a natural bone as grade "4" on a scale of 0 to 5, in which 5 is the closest to the natural bone and 0 the farthest from the natural bone. All structures proposed in the method were found with the proposed color. Conclusion: It is concluded that it is feasible to use biomodels in surgical training of specialist doctors. After dissection of the bone biomodel, it was possible to find the anatomical structures proposed, and to reproduce the surgical approaches most used in surgical practice and training implants (AU)

Computed tomography window affects kidney stones measurements

ABSTRACT Objectives Measurements of stone features may vary according to the non-contrast computed tomography (NCCT) technique. Using magnified bone window is the most accurate method to measure urinary stones. Possible differences between stone measurements in different NCCT windows have not been evaluated in stones located in the kidney. The aim of this study is to compare measurements of kidney stone features between NCCT bone and soft tissue windows in patients submitted to retrograde intrarenal surgery (RIRS). Materials and Methods Preoperative and 90th postoperative day NCCT were performed in 92 consecutive symptomatic adult patients (115 renal units) with kidney stones between 5 mm to 20 mm (< 15 mm in the lower calyx) treated by RIRS. NCCT were evaluated in the magnified bone window and soft tissue window in three axes in a different time by a single radiologist blinded for the measurements of the NCCT other method. Results Stone largest size (7.92±3.81 vs. 9.13±4.08; mm), volume (435.5±472.7 vs. 683.1±665.0; mm3) and density (989.4±330.2 vs. 893.0±324.6; HU) differed between bone and soft-tissue windows, respectively (p<0.0001) 5.2% of the renal units (6/115) were reclassified from residual fragments > 2 mm on soft tissue window to 0-2 mm on bone window. Conclusion Kidney stone measurements vary according to NCCT window. Measurements in soft tissue window NCCT of stone diameter and volume are larger and stone density is lesser than in bone window. These differences may have impact on clinical decisions.

Use of 3d printing in preoperative planning and training for aortic endovascular repair and aortic valve disease

Abstract Introduction: Three-dimensional (3D) printing has become an affordable tool for assisting heart surgeons in the aorta endovascular field, both in surgical planning, education and training of residents and students. This technique permits the construction of physical prototypes from conventional medical images by converting the anatomical information into computer aided design (CAD) files. Objective: To present the 3D printing feature on developing prototypes leading to improved aortic endovascular surgical planning, as well as transcatheter aortic valve implantation, and mainly enabling training of the surgical procedure to be performed on patient's specific condition. Methods: Six 3D printed real scale prototypes were built representing different aortic diseases, taken from real patients, to simulate the correction of the disease with endoprosthesis deployment. Results: In the hybrid room, the 3D prototypes were examined under fluoroscopy, making it possible to obtain images that clearly delimited the walls of the aorta and its details. The endovascular simulation was then able to be performed, by correctly positioning the endoprosthesis, followed by its deployment. Conclusion: The 3D printing allowed the construction of aortic diseases realistic prototypes, offering a 3D view from the two-dimensional image of computed tomography (CT) angiography, allowing better surgical planning and surgeon training in the specific case beforehand.

Three-dimensional virtual reconstruction as a tool for preoperative planning in the management of complex anorectal fistulas / Reconstrução virtual tridimensional como ferramenta de planejamento pré-operatório de fístulas anais complexas

ABSTRACT The making of three-dimensional virtual models is a promising technology in preoperative planning, but that is not used in the treatment of anorectal fistulas. The objective of this work is to describe the development and initial experience of the construction of a virtual three-dimensional model of the pelvic anatomy of a patient, allowing the exact identification of the relationships between the fistulous tracts of complex anorectal fistulas and the other pelvic structures. An MRI was performed on this patient, and the images were exported to the Vitrea fX Workstation® software. A radiologist did the analysis and segmentation of the images that were then sent to a three-dimensional image processor (Meshlab v. 1.3.3 - ISTI - CNR Research Center, Pisa University, Italy®). The final 3D color image was analyzed by the surgeon and used to guide the catheterization of the fistulous pathways, the internal orifice and to assist in the identification of adjacent structures. The final three-dimensional model presented a high correlation with the intraoperative findings and facilitated the surgical planning.

RESUMO A criação de modelos virtuais tridimensionais é uma tecnologia promissora no planejamento pré-operatorio, entretanto não é utilizada no tratamento de fistulas anais. O objetivo desse trabalho é descrever o desenvolvimento e a experiência inicial da construção de um modelo virtual tridimensional da anatomia pélvica de um paciente, que permite a identificação exata das relações entre os tratos fistulosos de fistulas anais complexas e as demais estruturas pélvicas. O paciente realizou uma ressonância magnética e as imagens foram exportadas para o programa Vitrea fX software Workstation®. Um radiologista realizou a analise e segmentação das imagens que, em seguida, foram enviadas para um processador de imagens tridimensionais (Meshlab v. 1.3.3 - ISTI - CNR research center, Pisa University, Italy®). A imagem 3D colorida final foi analisada pelo cirurgião e utilizada para guiar a cateterização dos trajetos fistulosos e orifício interno e para auxiliar na identificação das estruturas adjacentes. O modelo tridimensional final apresentou alta correlação com os achados intraoperatorios e facilitou o planejamento cirúrgico.

Identification and differentiation of Candida species from pediatric patients by random amplified polymorphic DNA

Thirty-four Candida isolates were analyzed by random amplified polymorphic DNA using the primer OPG-10:24 Candida albicans; 4 Candida tropicalis; 2 Candida parapsilosis; 2 Candida dubliniensis; 1 Candida glabrata and 1 Candida krusei. The UPGMA-Pearson correlation coefficient was used to calculate the genetic distance between the different Candida groupings. Samples were classified as identical (correlation of 100 percent); highly related samples (90 percent); moderately related samples (80 percent) and unrelated samples (< 70 percent). The results showed that the RAPD proposed was capable of classifying the isolates coherently (such that same species were in the same dendrogram), except for two isolates of Candida parapsilosis and the positive control (Netherlands, 1973), probably because they are now recognized as three different species. Concerning the only fluconazole-resistant Candida tropicalis isolate with a genotype that was different to the others, the data were insufficient to affirm that the only difference was the sensitivity to fluconazole. We concluded that the Random Amplified Polymorphic DNA proposed might be used to confirm Candida species identified by microbiological methods.

Trinta e quatro isolados de Candida foram analisados por amplificação aleatória de DNA polimórfico (primer OPG-10): 24 Candida albicans, 4 Candida tropicalis, 2 Candida parapsilosis, 2 Candida dubliniensis, 1 Candida glabrata e 1 Candida krusei. O coeficiente de correlação de Pearson-UPGMA calculou a distância genética entre os diferentes agrupamentos de Candida: amostras idênticas (100 por cento de correlação), amostras muito relacionadas (90 por cento), moderadamente relacionadas (80 por cento), e não relacionadas (< 70 por cento). Os resultados demonstram que a amplificação aleatória de DNA polimórfico proposta é capaz de classificar os isolados de forma coerente, ficando os de mesma espécie em um mesmo dendograma, com exceção dos dois isolados de Candida parapsilosis e o controle positivo (Holanda, 1973), provavelmente por serem atualmente classificadas em três espécies diferentes. Quanto ao único isolado de Candida tropicalis resistente ao fluconazol com genótipo diferente dos outros, os dados não são suficientes para afirmar que a única característica distinta fosse a sensibilidade ao fluconazol. Concluímos que a amplificação aleatória de DNA polimórfico proposta poderia ser usada para a confirmação das espécies de Candida identificadas nos testes microbiológicos.