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PROPOSIÇÃO Avaliou-se radiograficamente o grau de precisão de um guia radiográfico-cirúrgico na predição do posicionamento final de mini-implantes inseridos no septo inter-radicular e, sequencialmente, determinou-se um índice de risco para normatizar a indicação do procedimento de inserção dos mini-implantes. MATERIAL E MÉTODOS Um total de 53 mini-implantes foram inseridos no septo inter-radicular vestibular da região posterior da maxila e/ou mandíbula de 27 pacientes com idade média de 19,17 ± 9,06 anos (idade mínima de 12,72 anos e máxima de 56,37 anos). O Guia Radiográfico-Cirúrgico Graduado (GRCG) foi utilizado para inserir os mini-implantes no centro do septo de forma equidistante em relação às raízes dos dentes adjacentes. As distâncias entre o mini-implante e as raízes dos dentes adjacentes foram mensuradas nas 53 radiografias pós-cirúrgicas com intuito de avaliar a precisão do GRCG a partir do grau de centralização do mini-implante no septo. O grau de imprecisão do GRCG foi associado à largura do septo e ao diâmetro do mini-implante para compor a fórmula do índice de risco utilizada na avaliação do risco cirúrgico de inserção dos mini-implantes. RESULTADOS O grau de imprecisão do GRCG mostrou que, em média, os mini-implantes foram inseridos com um desvio de 0,13mm (±0,13) em relação ao centro do septo. O valor médio do índice de risco (IR) foi menor do que 1, significando um reduzido risco cirúrgico. CONCLUSÕES A ligação estabelecida entre os procedimentos radiográfico e cirúrgico proveu ao GRCG um reduzido grau de imprecisão de 0,13mm, e uma acurada predição do posicionamento final do mini-implante no septo inter-radicular, contribuindo para um reduzido risco cirúrgico (IR<1). / OBJECTIVE This study evaluated the radiographic-surgical guide accuracy to predict post-surgical mini-implant positioning in the interradicular septum. Additionally, a risk index to standardize surgical procedure indication for mini-implant insertion was determined. MATERIAL AND METHODS A total of fifty-three titanium mini-implants were placed in the buccal interradicular septum of the posterior maxillary and/or mandibular region of 27 patients with a mean age of 19.17 ± 9.06 years (ranging from 12.72 to 56.37 years). The Graduated Radiographic-Surgical Guide (GRSG) was used to insert mini-implants in the interradicular septum in a centralized and equidistant position regarding adjacent tooth roots. The fifty-three post-surgical radiographs were used to measure the distances between mini-implants and adjacent tooth roots to evaluate GRSG accuracy in obtaining mini-implant centralized position in the septum. The GRSG inaccuracy degree was related to the septum width and the mini-implant diameter to obtain risk index formula, which was used to predict surgical risks during mini-implants insertion. RESULTS The GRSG inaccuracy degree showed that, on average, the mini-implants were 0.13mm (±0.13) displaced regarding the centralized position initially intended. The risk index (RI) presented a mean value smaller than 1, indicating a reduced surgical risk. CONCLUSION The link established between radiographic and surgical procedures propitiated a small GRSG inaccuracy degree of 0.13mm, allowing an accurate prediction of the final mini-implant positioning in the interradicular septum, which contributed to a low surgical risk (RI<1).

PROPOSIÇÃO Avaliou-se radiograficamente o grau de precisão de um guia radiográfico-cirúrgico na predição do posicionamento final de mini-implantes inseridos no septo inter-radicular e, sequencialmente, determinou-se um índice de risco para normatizar a indicação do procedimento de inserção dos mini-implantes. MATERIAL E MÉTODOS Um total de 53 mini-implantes foram inseridos no septo inter-radicular vestibular da região posterior da maxila e/ou mandíbula de 27 pacientes com idade média de 19,17 ± 9,06 anos (idade mínima de 12,72 anos e máxima de 56,37 anos). O Guia Radiográfico-Cirúrgico Graduado (GRCG) foi utilizado para inserir os mini-implantes no centro do septo de forma equidistante em relação às raízes dos dentes adjacentes. As distâncias entre o mini-implante e as raízes dos dentes adjacentes foram mensuradas nas 53 radiografias pós-cirúrgicas com intuito de avaliar a precisão do GRCG a partir do grau de centralização do mini-implante no septo. O grau de imprecisão do GRCG foi associado à largura do septo e ao diâmetro do mini-implante para compor a fórmula do índice de risco utilizada na avaliação do risco cirúrgico de inserção dos mini-implantes. RESULTADOS O grau de imprecisão do GRCG mostrou que, em média, os mini-implantes foram inseridos com um desvio de 0,13mm (±0,13) em relação ao centro do septo. O valor médio do índice de risco (IR) foi menor do que 1, significando um reduzido risco cirúrgico. CONCLUSÕES A ligação estabelecida entre os procedimentos radiográfico e cirúrgico proveu ao GRCG um reduzido grau de imprecisão de 0,13mm, e uma acurada predição do posicionamento final do mini-implante no septo inter-radicular, contribuindo para um reduzido risco cirúrgico (IR<1). / OBJECTIVE This study evaluated the radiographic-surgical guide accuracy to predict post-surgical mini-implant positioning in the interradicular septum. Additionally, a risk index to standardize surgical procedure indication for mini-implant insertion was determined. MATERIAL AND METHODS A total of fifty-three titanium mini-implants were placed in the buccal interradicular septum of the posterior maxillary and/or mandibular region of 27 patients with a mean age of 19.17 ± 9.06 years (ranging from 12.72 to 56.37 years). The Graduated Radiographic-Surgical Guide (GRSG) was used to insert mini-implants in the interradicular septum in a centralized and equidistant position regarding adjacent tooth roots. The fifty-three post-surgical radiographs were used to measure the distances between mini-implants and adjacent tooth roots to evaluate GRSG accuracy in obtaining mini-implant centralized position in the septum. The GRSG inaccuracy degree was related to the septum width and the mini-implant diameter to obtain risk index formula, which was used to predict surgical risks during mini-implants insertion. RESULTS The GRSG inaccuracy degree showed that, on average, the mini-implants were 0.13mm (±0.13) displaced regarding the centralized position initially intended. The risk index (RI) presented a mean value smaller than 1, indicating a reduced surgical risk. CONCLUSION The link established between radiographic and surgical procedures propitiated a small GRSG inaccuracy degree of 0.13mm, allowing an accurate prediction of the final mini-implant positioning in the interradicular septum, which contributed to a low surgical risk (RI<1).

Objective: The purpose of this study was to evaluate the accuracy of surgical guides for dental implant placement fabricated by additive and subtractive techniques. Methods: A standardized mandible model (BoneModels, Castellón, Spain) was duplicated and the proposed implant position was performed from a diagnostic wax-up. An implant was placed in the printed model as a reference. Cone beam computed tomography (CBCT) was made with the radiographic surgical guide to design a surgical guide on BlueSky Plan 4 software. The .stl file of the surgical guide was exported and fabricated by two different techniques: additive (3D printing) and subtractive (milling). Fifteen surgical guides per group were used to place implants in the printed models. The angular deviations, differences in depth, coronal and apical deviations were measured using GeoMagic Control X software. Results were analyzed by Wilcoxon-Mann-Whitney (Wilcoxon Rank Sum) test and PERMANOVA (Permutational Multivariate Analysis of Variance). Intraclass correlation was used to analyze the reproducibility. A 0.05 level of significance was used, with Bonferroni multiple adjustment as needed. Results: There were no significant differences in accuracy of implant placement using additive technique vs subtractive techniques. The mean angular deviations between planned and actual position of implant in mesio-distal cross-section were 0.780±0.803 degrees for printed group and 0.772±0.724 degrees for the milled group. The analogous results in bucco-lingual cross-section were 1.601±1.223 degrees in in printed group and 1.767±0.762 degrees in the milled group. The differences in depth (mm) were measured in four aspects including mesial, distal, buccal and lingual. The mean differences in depth in the group that using printed surgical guides were 0.373±0.285 mm, 0.325±0.230 mm, 0.240±0.228 mm, and 0.247±0.168 mm in those 4 aspects, respectively. The mean differences in depth in the group that using milled surgical guides were 0.511±0.326 mm, 0.396±0.316 mm, 0.215±0.230 mm, and 0.230±0.122 mm in those four aspects, respectively. The mean coronal deviation showed 0.32 mm in the printed group and 0.27 mm in the milled group. For the apical deviation, the results of this study showed mean apical deviation 0.84 mm in the printed group and 0.80 mm in the milled group. Conclusions: No statistically significant difference was identified between the position of implant placed using surgical guide fabricated by the additive technique (3D printing) vs surgical guides fabricated by subtractive technique (milling). The 3D-printed surgical guide could be an alternative for guided-implant surgery with the benefits of high accuracy, ease of fabrication and reduction of laboratory time and materials, thereby increasing cost-effectiveness.

Objectives: To evaluate and compare an experimental surgical navigation system (ESNS) in implant placement accuracy to static planning and transfer systems. Material and Methods: Partially edentulous, surgical typodonts were used to simulate prosthetically-driven osteotomies in preclinical setting. After cbCT acquisition the DICOM files were used to reverse plan and fabricate surgical guides. Manual placement, three static guiding systems and ESNS were compared. Eight osteotomies per jaw were transferred to 10 typodonts in five series, resulting in 400 osteotomies by 3 operators, each modality. Lateral, vertical, total and angular deviations were measured and compared. Results: Computer-assisted systems were comparable and provided superior precision laterally and in angulation, but not vertically; implants placed in free-end positions were less accurate. Conclusions: All computer-aided methods showed less than 2 mm or 5 degrees error on average, which needs to be considered in clinical practice.

Objectives: To evaluate and compare an experimental surgical navigation system (ESNS) in implant placement accuracy to static planning and transfer systems. Material and Methods: Partially edentulous, surgical typodonts were used to simulate prosthetically-driven osteotomies in preclinical setting. After cbCT acquisition the DICOM files were used to reverse plan and fabricate surgical guides. Manual placement, three static guiding systems and ESNS were compared. Eight osteotomies per jaw were transferred to 10 typodonts in five series, resulting in 400 osteotomies by 3 operators, each modality. Lateral, vertical, total and angular deviations were measured and compared. Results: Computer-assisted systems were comparable and provided superior precision laterally and in angulation, but not vertically; implants placed in free-end positions were less accurate. Conclusions: All computer-aided methods showed less than 2 mm or 5 degrees error on average, which needs to be considered in clinical practice.

Minimally invasive spine surgery (MISS) has proven to be advantageous over traditional open surgery as it minimizes the likelihood of tissue damage and infections. During MISS, surgeons create small incisions to allow access to the surgery site, however, opting for smaller incisions decreases the surgeon’s field of vision. To compensate, surgeons rely on preoperative and intraoperative ionizing imaging technologies for guidance. Conventional localization of the spine, registration of digital images to the patient during surgery, depends heavily on the surgeon’s anatomical knowledge and their experience. Preoperative images are typically created using 3D technology while intraoperative images use 2D technology. While the integration of preoperative 3D images and intraoperative 2D images can provide valuable assistance, patient’s preoperative and intraoperative positions do not coincide leading to additional use of ionizing imaging. The objective of this research was to propose a workflow that assists with image registration for MISS. The main component of the workflow was the creation of a script that automatically generates patient-specific digital guides, which will then be manufactured, to align the patient’s intraoperative and preoperative body position. By aligning the patient’s positions, the 3D printed surgical guide serves as a shared feature between the preoperative digital image and the actual patient. This allows for the intraoperative image to be registered to the preoperative image more accurately. Additionally, the guide acts as an attachment site for any additional instrument guides/supports. The surgical guide generating script utilizes the skin contour of patient’s torso region, extracted from medical images, to automatically produce the guide’s horizontal and vertical components. Adjustments are made to the components using CAD software before proceeding to manufacturing, via 3D printing, and assembly of the guide. To validate the workflow, more specifically the script’s ability to automatically generate surgical guides that fit over the patient’s back, a guide was created for a mannequin. The maximum gap between the mannequin and the horizontal components was 0.8 cm and 1.5 cm for the vertical component.

No description available.

A subluxação atlantoaxial em cães miniatura culmina em compressão da medula espinhal e mielopatia cervical de graus variáveis. Frequentemente o tratamento cirúrgico se faz necessário, sendo os implantes transarticulares uma das opções terapêuticas. Convencionalmente a passagem desses implantes baseia-se em pontos anatômicos de referência e ângulos genéricos preestabelecidos, todavia, devido ao estreito corredor ósseo o posicionamento ideal é desafiador. O desenvolvimento de métodos de planejamento cirúrgico individualizados poderia aumentar a acurácia na aplicação de implantes atlantoaxiais. O presente estudo teve como objetivo desenvolver um guia cirúrgico paciente-específico (GCPE) para colocação de pinos atlantoaxiais em cães miniaturas e comparar a eficácia desses dispositivos em relação a técnica cirúrgica convencional. Para tanto, dezesseis cadáveres de cães de até seis quilogramas foram dispostos aleatoriamente em dois grupos de oito cães, para serem submetidos a cirurgia de estabilização transarticular atlantoaxial com pinos lisos de 1,6 mm. Nos cães do Grupo A (GrA) a aplicação dos pinos foi guiada por um GCPE, desenvolvido com base em imagens de tomografia computadorizada (TC), a partir de técnicas de prototipagem rápida e impressão 3D por modelagem por fusão e deposição. Os cães do Grupo B (GrB), foram submetidos ao procedimento operatório convencional, sendo a passagem dos pinos guiada por referências anatômicas. Posteriormente ambos os grupos foram submetidos à exame de TC para avaliação da acurácia dos pinos. Para a avaliação do posicionamento dos implantes criou-se uma escala que ponderou a manutenção nos corredores seguros e os classificou de acordo com a estabilidade oferecida e a segurança da aplicação. Observou-se que não houve diferença significativa entre o método com GCPE e a cirurgia convencional, sendo que ambos grupos tiveram resultados expressivos de pinos inadequadamente aplicados, incluindo violação de corticais com obliteração do forame vertebral em 3 (37,5%) cães do GrA e 4 (50%) cães do GrB e obliteração do forame transverso em 3 (37,5%) animais do GrA e 1 (12,5%) do GrB. A aplicação de pinos em posição adequada bilateralmente foi observada em apenas 2 (25%) cães de cada grupo. Concluímos que a confecção de um GCPE para pinos transarticulares em cães miniaturas é viável, todavia, o modelo criado não foi capaz de aumentar a eficácia e segurança da cirurgia em relação à técnica convencional. / The atlantoaxial subluxation in miniature dogs leads to spinal cord compression and cervical myelopathy in several degrees. Commonly the surgical treatment is necessary, and one of therapeutic options are the transarticular fixation. Conventionally the passage of these implants is based on anatomical reference points and generics pre-established angles, however, due to the narrow bony corridor the ideal positioning is challenging. The development of individual surgical planning methods could improve the accuracy of atlantoaxial implants application. The present study aimed to develop a patient-specific surgical guide (PSSG) for placement of atlantoaxial pins in miniature dogs and to compare the efficacy of these devices related to the conventional surgical technique. Sixteen cadavers of dogs, up to six kilograms, were randomly placed in two groups of eight dogs each, to undergo atlantoaxial transarticular stabilization with Kirschner wires. On the Group A (GrA) the application of Kirschner wire were guided by a PSSG, developed based on computed tomography (CT) images, using rapid prototyping and fused deposition modeling 3D impression technique. The dogs of Group B (GrB) were submitted to conventional procedure, with the passage of the Kirschner wires guided by anatomical references. After surgeries, dogs in both groups were submitted to a CT scan to evaluate the accuracy of the implants. To evaluate the implants position a scale was created and considered the maintenance of the pins in the safe corridors and classified them according to the stability and safety of the application. It was observed that there was no significant difference between the PSSG method and the conventional surgery, and that both groups had expressive results of inappropriately applied pins, including obliteration of vertebral foramen in 3 (37.5%) dogs from GrA and 4 (50%) dogs from GrB and obliteration of the transverse foramen in 3 (37.5%) dogs from GrA and 1 (12, 5%) dog of GrB. The bilaterally application of pins in a suitable position was observed in only 2 (25%) dogs of each group. We concluded that the development of a PSSG for transarticular pins in miniature dogs is feasible, however, the model that we design was not able to increase the efficacy and safety of the surgery, compared to the conventional surgical technique.