Challenges of computer-assisted orthognathic surgery in clinical application / 口腔疾病防治

@#After years of development, the advantages of computer-assisted orthognathic surgery have been widely recognized. However, the clinical application of this technology is challenging. Each step may generate errors from data acquisition, computer-assisted diagnosis, and computer-assisted surgical design, causing errors to be transferred from the virtual surgical plan to the operation. The accumulation and amplification of errors will affect the final surgical effect. Currently, digital devices, such as intraoral scanners, are being explored for error control, utilizing automation methods and algorithms, and implementing personalized bone positioning methods. Moreover, there are still many problems that have not been fully resolved, such as precise simulation of postoperative soft tissue, functional assessment of mandibular movement, and absorbable internal fixation materials. Fully understanding computer-assisted orthognathic surgery's limitations could provide direction for optimizing existing methods while helping clinicians avoid risks and maximize its advantages to achieve the best outcome. Many emerging and cutting-edge technologies, such as personalized titanium plates, artificial intelligence, and surgical robots, will further promote the development of this discipline. We can expect future optimization of digital orthognathic surgical technology by innovations in automation, intelligence, and personalization.

Clinical application of perforator vessel location guide plate for fibular musculocutaneous flaps / 口腔疾病防治

Objective@#Based on 3D printing technology, explore the precision of a perforator vessel location guide plate for fibular musculocutaneous flaps before the transplantation of fibular osteocutaneous flaps and evaluate its application effects.@*Methods@#This study was reviewed and approved by the ethics committee, and informed consent was obtained from the patients. From May 2019 to October 2022, 14 patients with jaw defects who needed to undergo fibular perforator flap transplantation at the First Affiliated Hospital of Xinjiang Medical University were selected. For the seven patients in the guide plate group, CTA was combined with Mimics software to reconstruct both lower limbs, and the perforator vessel positioning guide for locating perforator vessels was designed; the two ends of the guide plate were designed as fixed ends, with the upper end fixed to the knee joint and the lower end fixed to the ankle joint, and the guide plate was fabricated by a 3D printer. For the seven patients in the control group, a conventional handheld Doppler probe was used for perforator vessel location. The average operation time, bleeding volume, recovery time, deviation of perforator vessel location, postoperative flap-related complications, postoperative donor site shape satisfaction, and lower extremity functional scale (LEFS) score were recorded. SPSS 25.0 software was used for statistical analysis.@*Results@#The average operation time, bleeding volume, recovery time, deviation of perforator vessel location and postoperative donor site shape satisfaction were significantly better in the guide plate group than in the control group (P<0.05); moreover, the differences in postoperative flap-related complications and LEFS scores were not statistically significant (P>0.05).@*Conclusion@#Based on 3D printing technology, fibular musculocutaneous flap perforator vessels can be more accurately located using a guide plate and the knee and ankle as fixed points, and this method can effectively stabilize the guide position, prevent soft tissue offset, and improve positioning accuracy and thus deserves to be generalized.

3D printed Mg-incorporated polycaprolactone scaffolds for repairing rat skull defects / 口腔疾病防治

Objective@#To evaluate the bone repair effect of 3D-printed magnesium (Mg)-loaded polycaprolactone (PCL) scaffolds in a rat skull defect model.@*Methods@#PCL scaffolds mixed with Mg microparticles were prepared by using 3D printing technology, as were pure PCL scaffolds. The surface morphologies of the two scaffolds were observed by scanning electron microscopy (SEM), and the surface elemental composition was analyzed via energy dispersive spectroscopy (EDS). The physical properties of the scaffolds were characterized through contact angle measurements and an electronic universal testing machine. This study has been reviewed and approved by the Ethics Committee. A critical size defect model was established in the skull of 15 Sprague-Dawley (SD) rats, which were divided into the PCL group, PCL-Mg group, and untreated group, with 5 rats in each group. Micro-CT scanning was performed to detect and analyze skull defect healing at 4 and 8 weeks after surgery, and samples from the skull defect area and major organs of the rats were obtained for histological staining at 8 weeks after surgery.@*Results@#The scaffolds had a pore size of (480 ± 25) μm, a fiber diameter of (300 ± 25) μm, and a porosity of approximately 66%. The PCL-Mg scaffolds contained 1.0 At% Mg, indicating successful incorporation of Mg microparticles. The contact angle of the PCL-Mg scaffolds was 68.97° ± 1.39°, indicating improved wettability compared to that of pure PCL scaffolds. Additionally, compared with that of pure PCL scaffolds, the compressive modulus of the PCL-Mg scaffolds was (57.37 ± 8.33) MPa, demonstrating enhanced strength. The PCL-Mg group exhibited the best bone formation behavior in the skull defect area compared with the control group and PCL group at 4 and 8 weeks after surgery. Moreover, quantitative parameters, such as bone volume (BV), bone volume/total volume (BV/TV), bone surface (BS), bone surface/total volume (BS/TV), trabecular thickness (Tb.Th), trabecular number (Tb.N) and bone mineral density (BMD), of skull defects were better than those in the other groups, indicating the best bone regeneration effect. H&E, Goldner, and VG staining revealed more mineralized new bone formation in the PCL-Mg group than in the other groups, and H&E staining of the major organs revealed good biosafety of the material.@*Conclusion@#PCL-Mg scaffolds can promote the repair of bone defects and have clinical potential as a new scaffold material for the repair of maxillofacial bone defects.

Improved unilateral puncture PVP based on 3D printing technology for the treatment of osteoporotic vertebral compression fracture / 中国骨伤

OBJECTIVE@#To investigate the clinical effect of unilateral percutaneous vertebroplasty (PVP) combined with 3D printing technology for the treatment of thoracolumbar osteoporotic compression fracture.@*METHODS@#A total of 77 patients with thoracolumbar osteoporotic compression fractures from October 2020 to April 2022 were included in the study, all of which were vertebral body compression fractures caused by trauma. According to different treatment methods, they were divided into experimental group and control group. Thirty-two patients used 3D printing technology to improve unilateral transpedicle puncture vertebroplasty in the experimental group, there were 5 males and 27 females, aged from 63 to 91 years old with an average of (77.59±8.75) years old. Forty-five patients were treated with traditional bilateral pedicle puncture vertebroplasty, including 7 males and 38 females, aged from 60 to 88 years old with an average of(74.89±7.37) years old. Operation time, intraoperative C-arm X-ray times, anesthetic dosage, bone cement injection amount, bone cement diffusion good and good rate, complications, vertebral height, kyphotic angle (Cobb angle), visual analogue scale(VAS), Oswestry disability index (ODI) and other indicators were recorded before and after surgery, and statistically analyzed.@*RESULTS@#All patients were followed up for 6 to 23 months, with preoperative imaging studies, confirmed for thoracolumbar osteoporosis compression fractures, two groups of patients with postoperative complications, no special two groups of patients' age, gender, body mass index (BMI), time were injured, the injured vertebral distribution had no statistical difference(P>0.05), comparable data. Two groups of patients with bone cement injection, bone cement dispersion rate, preoperative and postoperative vertebral body height, protruding after spine angle(Cobb angle), VAS, ODI had no statistical difference(P>0.05). The operative time, intraoperative fluoroscopy times and anesthetic dosage were statistically different between the two groups(P<0.05). Compared with the traditional bilateral puncture group, the modified unilateral puncture group combined with 3D printing technology had shorter operation time, fewer intraoperative fluoroscopy times and less anesthetic dosage. The height of anterior vertebral edge, kyphosis angle (Cobb angle), VAS score and ODI of the affected vertebrae were statistically different between two groups at each time point after surgery(P<0.05).@*CONCLUSION@#In the treatment of thoracolumbar osteoporotic compression fractures, 3D printing technology is used to improve unilateral puncture PVP, which is convenient and simple, less trauma, short operation time, fewer fluoroscopy times, satisfactory distribution of bone cement, vertebral height recovery and kyphotic Angle correction, and good functional improvement.

Microtensile bond strength of resin cements to 3-D printed and milled temporary restorative resins / Resistencia de unión en microtracción de cementos resinosos a resinas para provisionales impresas y fresadas

Abstract To evaluate the microtensile bond strength (µTBS) of two resin cements to 3D printed and milled CAD/CAM resins used for provisional fixed partial dentures. Blocks (5 x 5 x 5 mm) of three 3D-printed resins (Cosmos3DTemp / Yller; Resilab3D Temp / Wilcos and SmartPrint BioTemp, / MMTech) were printed (Photon, Anycubic Technology Co.). A milled material (VitaCAD-Temp, VITA) was used as control. Half the specimens were sandblasted and the rest were untreated. Two blocks were bonded with the corresponding resin cement: PanaviaV5 (Kuraray Noritake) and RelyX Ultimate (3M Oral Care). After 24 hours, the bonded blocks were sectioned into 1 x 1 mm side sticks. Half the beams were tested for µTBS and the other half was thermocycled (5000 cycles, 30s dwell-time, 5s transfer time) before µTBS testing. A four way Generalized Linear Model (material*sandblasting*cement*aging) analysis was applied. VITA exhibited the lowest µTBS, regardless of the cement, sandblasting and thermocycling. Sandblasting significantly improved the µTBS of VIT, especially after aging, but did not improve the µTBS of 3D printed resins. Sandblasting was not beneficial for 3D printed resins, although is crucial for adhesive cementation of milled temporary resins. Airborne particle abrasion affects the integrity of 3D-printed resins, without producing a benefit on the microtensile bond strength of these materials. However, sandblasting is crucial to achieve a high bond strength on milled temporary resins.

Resumen Evaluar la resistencia adhesiva en microtracción (µTBS) de dos cementos resinosos a resinas CAD/CAM impresas y fresadas indicadas para restauraciones provisionales. Bloques (5 x 5 x 5mm) de tres resinas impresas (Cosmos3DTemp / Yller; Resilab3D Temp / Wilcos and SmartPrint BioTemp, / MMTech) y una resina fresada (VitaCAD-Temp, VITA) fueron fabricados. La mitad de los especímenes fueron arenados y el resto no recibió tratamiento mecánico. Dos bloques con condiciones de tratamiento iguales fueron cementados con cemento resinoso (PanaviaV5 / Kuraray Noritake y RelyX Ultimate / 3M Oral Care). Después de 24 horas los bloques fueron seccionados en palitos de 1 mm² de área. En la mitad de los especímenes se midió la TBS inmediatamente y el resto fue termociclado (5000 ciclos, 30s remojo, 5s transferencia) antes de la prueba de TBS. Se aplica un análisis estadístico por Modelo Linear General con 4 factores (material*arenado*cemento*termociclado). La resina VITA presentó la menor µTBS, independientemente del cemento usado, el arenado y el termociclado. Sin embargo, el arenado aumentó la µTBS de VIT, especialmente después del termociclado. Por otro lado, el arenado no resultó en un aumento significativo de la µTBS de las resinas impresas. El arenado no fue beneficiosos para las resinas impresas, aunque es un paso crucial para la cementación adhesive de las resinas fresadas. El arenado afecta la integridad de las capas de las resinas impresas, sin generar un beneficio en la TBS.

Anatomía de la cámara pulpar y sistema de conductos radiculares: Estrategias pedagógicas unarevisión de literatura / Anatomy of the pulp chamber and the root canal system: Pedagogical strategiesAliterature review

Antecedentes: El conocimiento anatómico de la cámara pulpar y del sistema de conductos radiculareses fundamental para el correcto diagnóstico y planificación del tratamiento en endodoncia. Las herramientas pedagógicasdirigidasa los estudiantes de odontologíacomo apoyo en los procesos formativosde la asignatura de endodoncia favorecen la apropiación del conocimiento e identificación de las variantes morfológicas del sistema de conductos radiculares, que permiten al estudiantela integración del conocimiento. Objetivo:Identificar mediante una revisión de la literatura las estrategias pedagógicas que se utilizan para la enseñanza de morfología del sistema de conductos radiculares en endodoncia. Materiales y métodos: Se realizó una búsqueda bibliográfica de estudios originales en las bases de datos Medline (Pubmed), SciELO, Lilacs, Medline (Ovid), Web of science, Scopus, Embase, Google académico, eligiendo estudios publicadosa partir del año 2010 al 2022, para la selección de los artículos definitivos se seleccionaron estudios concernientes a procesos pedagógicos en endodoncia, excluyendo así otros tipos de enfoques en el área de odontología. Resultados: Se identificaron un total de 63 referencias, los cuales fueron analizados y seleccionados16, siendo excluidos 47 por no cumplir los criterios de inclusión. Conclusión: El uso de herramientas pedagógicas virtuales, didácticas y tecnológicas propician un efecto positivo en el estudiante de pregrado de odontología durante el aprendizaje de anatomía de sistemas de conductos radiculares que aumentan la confianza y seguridad al momento de realizar un tratamiento endodóntico en pacientes

Background: Anatomical knowledge of the pulp chamber and the root canal system is essential for correct diagnosis and treatment planning in endodontics. The pedagogical tools aimed at dental students as support in the training processes of the endodontics subject favor the appropriation of knowledge and identification of the morphological variants of the root canal system, which allow the student the integration of knowledge. Objective: To identify, through a review of the literature, the pedagogical strategies used to teach morphology of the root canal system in endodontics. Materials and methods: A bibliographic search of original studies was carried out in the Medline (Pubmed), SciELO, Lilacs, Medline (Ovid), Web of Science, Scopus, Embase, and Google academic databases, choosing studies published from 2010 to 2022. , for the selection of the definitive articles, studies concerning pedagogical processes in endodontics were selected, thus excluding other types of approaches in the area of dentistry. Results: A total of 63 references were identified, 16 of which were analyzed and selected, 47 being excluded for not meeting the inclusion criteria. Conclusion: The use of virtual, didactic and technological pedagogical tools favor a positive effect on the dentistry undergraduate student while learning the anatomy of root canal systems that increase confidence and security when performing endodontic treatment in patients.

3D Printing characteristics and mechanical properties of a bio scaffold obtained from a Micro-CT Scan, using the fused deposition modeling technique

The objective is to determine which biopolymer has the best 3D printing characteristics and mechanical properties for the manufacture of a bioscaffold, using the fused deposition printing technique, with models generated from an STL file obtained from a Micro-CT scan taken from a bovine iliac crest bone structure. Through an experimental exploratory study, three study groups of the analyzed biopolymers were carried out with thirteen printed structures of each one. The first is made of 100% PLA. The second, 90B, we added 1g of diatom extract, and the third, 88C, differs from the previous one in that it also contains 1g of calcium phosphate. The 39 printed structures underwent a visual inspection test, which required the fabrication of a gold standard scaffold in resin, with greater detail and similarity to the scanned bone structure. Finally, the structures were subjected to a compressive force (N) to obtain the modulus of elasticity (MPa) and compressive strength (MPa) of each one of them. A statistically significant difference (p=0.001) was obtained in the printing properties of the biomaterial 88C, compared to 90B and pure PLA and the 88C presented the best 3D printing characteristics. In addition, it also presented the best mechanical properties compared to the other groups of materials. Although the difference between these was not statistically significant (p=0.388), in the structures of the 88C biomaterial, values of compressive strength (8,84692 MPa) and modulus of elasticity (43,23615 MPa) were similar to those of cancellous bone in the jaws could be observed. Because of this result, the 88C biomaterial has the potential to be used in the manufacture of bioscaffolds in tissue engineering.

El objetivo es determinar cuál biopolímero presenta las mejores características de impresión 3D y propiedades mecánicas para la fabricación de un bioandamiaje, utilizando la técnica de impresión por deposición fundida, con modelos generados a partir de un archivo en formato STL que se obtuvo de un Micro-CT Scan de una estructura osea de cresta iliaca bovina. Mediante un estudio exploratorio, se realizaron 3 grupos de estudio con trece estructuras impresas de cada uno. El primero, se compone 100% de PLA. El segundo, 90B, se le agrega 1g de extracto de diatomea, y el tercero, 88C, se diferencia del anterior ya que contiene además, 1g de fosfato de calcio. A las 39 estructuras impresas se les realizó una prueba de inspección visual, por lo que se requirió la confección de un patrón de oro en resina, con mayor detalle y similitud a la estructura ósea escaneada. Finalmente, las estructuras fueron sometidas a una fuerza compresiva (N) para la obtención del módulo de elasticidad (MPa) y de la resistencia compresiva (MPa) de cada una de ellas. Se obtuvo una diferencia estadísticamente significativa (p=0,001) en las propiedades de impresión del biomaterial 88C, con respecto al 90B y al PLA puro, presentando las mejores características de impresión 3D. Además, obtuvo las mejores propiedades mecánicas en comparación con los otros grupos de materiales. Aunque la diferencia entre estos no fue estadísticamente significativa (p=0,388), en las estructuras del biomaterial 88C, se pudieron observar valores de resistencia compresiva (8,84692 MPa) y módulo de elasticidad (43,23615 MPa) que son semejantes a los del hueso esponjoso de los maxilares. A razón de este resultado, el biomaterial 88C cuenta con el potencial para ser utilizado en la fabricación de bioandamiajes en la ingeniería tisular.

Nuevos Recursos Digitales y 3D en la Enseñanza de Anatomía. Experiencia Internacional Reportada en el "Sectra Users Meeting 2019", Karolinska Institutet, Suecia, antes de la Pandemia de COVID-19 / New Digital and 3D Resources in the Teaching of Anatomy. International Experience Reported in the "Sectra Users Meeting 2019", Karolinska Institutet, Sweden, Before the Pandemic COVID-19

El uso de nuevos recursos tecnológicos en la enseñanza de anatomía ha impulsado la necesidad de adaptar el modelo educativo haciéndolo más centrado en el estudiante, dinámico y participativo mediante herramientas digitales y 3D; orientando los conocimientos hacia su aplicación clínica, pero bajo un ajuste curricular que tiende a cursar menos horas presenciales en aula o laboratorio. Este trabajo describe la experiencia local de una nueva Escuela de Medicina en Chile, reportada el año 2018, además y otros trabajos de centros formadores presentados en el "SECTRA Users Meeting 2019 Estocolmo", Karolinska Institutet, Suecia. Este trabajo describe los reportes orales sobre la aplicación de nuevos recursos digitales como; la mesa de disección digital táctil SECTRA® y modelos anatómicos cadavéricos impresos en 3D Erler-Zimmer®, bases de datos sobre anatomía digital, además, su impacto en el desempeño académico, reportado por usuarios de diferentes países, tales como: Australia, Canadá, Chile, China, Colombia, Estados Unidos de Norteamérica (EUA) y Suecia. Los datos fueron recopilados y analizados a partir de la información reportada en las presentaciones orales y resúmenes entregados por los expositores. La gran mayoría de los países expositores declararon el uso combinado de recursos digitales y 3D sumados a los tradicionales para la enseñanza de anatomía. Sólo el representante de EUA declaró usar exclusivamente recursos digitales (en laboratorio y en línea), experiencia correspondiente a una joven e innovadora escuela de medicina. La mayoría de los centros docentes declaró utilizar la mesa de disección digital en una amplia proporción de sus contenidos curriculares, en asociación a plataformas tipo RIS/PACS como IDS7 portal de SECTRA o las utilizadas por el centro formador. El uso de nuevas tecnologías digitales y 3D ha ganado un importante espacio en el currículum de la enseñanza de anatomía, complementando el uso de los recursos tradicionales.

SUMMARY: The use of new technological resources in the teaching of anatomy has promoted the need to adapt the educational model, making it more student-centered, dynamic, and participatory through digital and 3D tools, directing the knowledge towards its clinical application, but under a curricular adjustment that tends to take fewer contact hours in the classroom or laboratory. This work describes the local experience of a new School of Medicine in Chile, reported in 2018, and other work from training centers presented at the "SECTRA Users Meeting 2019 Stockholm", Karolinska Institutet, Sweden. This work describes the oral reports on the application of new digital resources such as; the SECTRA® digital tactile dissection table and Erler- Zimmer® 3D printed cadaveric anatomical models, databases on digital anatomy, in addition, its impact on academic performance, reported by users from different countries, such as Australia, Canada, Chile, China, Colombia, United States of America (USA) and Sweden. The data was collected and analyzed from the information reported in the oral presentations and summaries delivered by the speakers.The vast majority of the exhibiting countries declared the combined use of digital and 3D resources added to the traditional ones for teaching anatomy. Only the representative from the USA stated that they exclusively used digital resources (in the laboratory and online), an experience corresponding to a young and innovative medical school. Most of the educational centers stated that they used the digital dissection table in a large proportion of their curricular contents, in association with RIS/PACS-type platforms such as the IDS7 SECTRA portal or those used by the training center. The use of new digital and 3D technologies has gained an important space in the anatomy teaching curriculum, complementing the use of traditional resources.

Guided Endodontic Surgery ? Case Series

This case report describes three cases in which periapical surgeries were carried out using a new surgical endodontic technique by using a three?dimensional (3D) printed template for guided osteotomy and root resection. In Case 1, the data obtained from preoperative CT scan and cast scan were transferred to a surgical planning software. The surgical template was printed using a 3D printer. Using the template, osteotomy and root?end resection were precisely carried out. In Case 2, after CBCT imaging, data were transferred to stereolithography and a 3D model was fabricated. With the help of the 3D model, a template was fabricated using tray material. This guided surgical template minimized the extent of osteotomy and enabled precise targeting of the apex. In Case 3, a preoperative CT scan aided in the fabrication of a surgical 3D template. The template assisted in the precise removal of the overlying cortical bone.

Prototyping and 3D printing of computed tomography images with an emphasis on soft tissues, especially muscles, for teaching human anatomy / Prototipado e impresión 3D de imágenes de tomografía computarizada con énfasis en los tejidos blandos, especialmente músculos, para la enseñanza de la anatomía humana

SUMMARY: The study on cadavers, although considered fundamental in the teaching of human anatomy, is limited in several universities, mainly due to the acquisition and manipulation of cadaveric material. Throughout history, several artificial anatomical models have been used to complement the real anatomical pieces. The present study offers a new alternative: the making of three-dimensional models from Computed Tomography (3D-CT) patient image acquisition. CT images from the USP University Hospital database were used. Patients underwent examinations for reasons other than the present study and were anonymized to maintain confidentiality. The CT slices obtained in thin cross-sections (approximately 1.0 mm thick) were converted into three-dimensional images by a technique named Volume Rendering for visualization of soft tissue and bone. The reconstructions were then converted to an STL (Standard Triangle Language) model and printed through two printers (LONGER LK4 Pro® and Sethi S3®), using PLA and ABS filaments. The 3D impressions of the thigh and leg muscles obtained better visual quality, being able to readily identify the local musculature. The images of the face, heart, and head bones, although easily identifiable, although seemed to present lower quality aesthetic results. This pilot study may be one of the first to perform 3D impressions of images from CT to visualize the musculature in Brazil and may become an additional tool for teaching.

El estudio en cadáveres, a pesar de considerarse un aspecto fundamental en la enseñanza de la anatomía humana, se encuentra limitado en varias universidades, principalmente por la adquisición y manipulación de material cadavérico. A lo largo de la historia se han utilizado varios modelos anatómicos artificiales para complementar las piezas anatómicas reales. El presente estudio ofrece una nueva alternativa: la elaboración de modelos tridimensionales a partir de la adquisición de imágenes de pacientes por Tomografía Computarizada (3D-CT). Se utilizaron imágenes de TC de la base de datos del Hospital Universitario de la USP. Los pacientes se sometieron a exámenes por razones distintas al presente estudio y fueron anonimizados para mantener la confidencialidad. Los cortes de TC obtenidos en secciones transversales delgadas (aproximadamente 1,0 mm de grosor) se convirtieron en imágenes tridimensionales mediante una técnica denominada Volume Rendering para la visualización de tejido blando y hueso. Luego, las reconstrucciones se convirtieron a un modelo STL (Standard Triangle Language) y se imprimieron a través de dos impresoras (LONGER LK4 Pro® y Sethi S3®), utilizando filamentos PLA y ABS. Se obtuvo una mejor calidad visual de las impresiones 3D de los músculos del muslo y la pierna, pudiendo identificar fácilmente la musculatura local. Las imágenes de la cara, el corazón y los huesos de la cabeza, aunque fácilmente identificables, parecían presentar resultados estéticos de menor calidad. Este estudio piloto puede ser uno de los primeros en realizar impresiones 3D de imágenes de TC para visualizar la musculatura y podría ser en una herramienta adicional para la enseñanza.

Evaluation specification of CT images for transapical transcatheter aortic valve replacement / 中国胸心血管外科临床杂志

@#According to the needs of CT image evaluation for transapical transcatheter aortic valve replacement (TAVR), 20 clinical questions were proposed by the Delphi method, 15 questions were initially determined, and 12 clinical questions were summarized and determined by domestic experts. PubMed, Web of Science, Wanfang, and CNKI databases were searched by computer to collect the relevant literature from inception to November 2022, and finally 53 studies were included. Based on evidence-based study and evaluation experience, 3 meetings were held to give recommendations for preoperative CT data acquisition method, preoperative imaging evaluation of aortic root, imaging evaluation of transapical approach, preoperative auxiliary guidance of TAVR by CT images combined with 3D printing, and postoperative imaging evaluation of transapical TAVR, hoping to promote the standardized and successful development of transapical TAVR in China.

Short term efficacy of 3D printed individualized prosthesis for precise reconstruction of bone and joint defects after upper limb microsurgical repair / 中华显微外科杂志

Objective:To evaluate the efficacy of 3D printed individualised prosthesis in treating bone and joint defects in upper limbs remained after earlier microsurgical repairs.Methods:From June 2019 to September 2021, 12 patients were treated in the Institute of Orthopaedic Trauma of PLA, the 80th Group Army Hospital for bone and joint defects in upper limb that had been remained after earlier repairs with soft tissue flaps. The defects were: 1 in completely severed wrist, 2 defects of digit metacarpal bone, 4 defects of interphalangeal joint, 4 defects of bones in radiocarpal joint and 1 defect of lunate bone. The area of soft tissue defect ranged from 1.5 cm×3.0 cm to 12.0 cm×18.0 cm, and the length of bone defects ranged from 2.5 to 8.5(average 3.64) cm. For incompletely severed and completely severed limbs, replantation of severed limbs (digits) were performed in the primary surgery and the repair of soft tissue defects were performed in the second stage surgery. The remaining defects of bone and joint were reconstructed by 3D printed individualised prostheses in the third stage surgery. Finger soft tissue defects were covered with a local flap in the primary surgery, and bone and joint defects were reconstructed with a 3D printed prosthesis in the second surgery. Finger soft tissue defects were covered with a local flap in the first phase, and bone and joint defects were reconstructed with a 3D printed prosthesis in the second phase. After the surgery, the bone integration between the broken end of the bone joint defect and the prosthesis was determined based on the X-ray results and the Paley fracture healing score standard. Simultaneously measured the Total Active Motion(TAM) of the forearm and hand joints. At 1, 2, 3, 6, 9 and 12 months after hospital discharge. Follow-up X-ray examinations were taken followed by examinations on the recovery of soft tissues and bones. The upper limb function was graded according to the Evaluation Trial Standards of Upper Limb Partial Functional of Hand Surgery of Chinese Medical Association.Results:Postoperative follow-up at outpatient clinic lasted for 6 to 26 months, with an average of 11.5 months. All flaps were free from necrosis and infection, also there was no infection in bones and joints. According to the Paley fracture healing scale, 10 patients were in excellent and 2 in good. In addition, according to the Evaluation Trial Standards of Upper Limb Partial Functional of Hand Surgery of Chinese Medical Association, 5 patients achieved upper limb function in excellent, 5 in good and 2 in fair. The ranges of motion of the affected wrists were 30°-42°(average 37.3°) for the implanted prostheses of distal end of radius and the radial shaft. Wrist flexion 40° to 55°(average 43.5°). The range of motion of finger and wrist was 60° to 70°(average 65.7°) with a metacarpal and phalangeal bone prosthesis.Conclusion:3D printed individually customised prostheses are safe, accurate and effective in repair of the remained bone and joint defects in upper limbs after primary and early stages of microsurgical flap repairs. It can effectively restore anatomical structures of bone and joint in upper limbs.

Digital and 3D printing technologies in design of superficial iliac circumflex artery flap for coverage of donor site of anterolateral thigh flap: Report of 8 cases / 中华显微外科杂志

Objective:To explore the efficacy of digital and 3D printing technologies on design of superficial iliac circumflex artery flap for coverage the donor site of anterolateral thigh flap(ALTF).Methods:Clinical data of 8 patients were studied retrospectively for treatment of soft tissue defects of hand in the Department of Hand Surgery, Wuxi NO.9 People's Hospital Affiliated to Soochow University, from April 2017 to October 2021. The patients were 6 males and 2 females, aged from 29 to 59 years(mean, 45.8 years). Cause of injury: 3 patients were crushed, 2 by hot pressing, and 3 by machine strangulation. Site of injury included: 5 cases were dorsal hand defects and 3 cases were palm defects. All the wounds were contaminated to varying degrees with soft tissue defects. The areas of soft tissue defect ranged from 11 cm×10 cm to 22 cm×14 cm. Four patients had combined injuries of open fracture of metacarpals and phalanges and 3 with tendon defects. All wounds were repaired by free ALTF transplantation. And the donor sites in the thigh were repaired by superficial iliac circumflex artery flaps. The secondary wounds caused by flap harvesting on abdominal wall were closed directly. The targeted perforator vessels were detected preoperatively by CTA combined with CDU. 3D printed models of the affected hand were obtained before operation for individualised repairs according to the shape and area of the wounds. After the operation, all patients entered scheduled follow-ups at the outpatient clinic and via internet by observing the flap shape and testing the recovery of sensory and movement of adjacent joint.Results:The shapes and sizes of the wounds and the flaps were found basically in accordance with those in the preoperative simulative designs. All flaps in 8 patients survived and the wounds healed completely. All patients entered follow-ups for 8 to 24(average, 17.5) months. The donor thighs presented good appearance and colour, pliability without bloating. The range of motion of the hips and knees was not affected. Only linear scars remained in the abdominal donor sites, with natural colour and appearance.Conclusion:Digital and 3D printing technologies in preoperative design of flaps can help to locate the perforator vessels intraoperatively and guide the individualised design of the flaps with improved operation efficiency and satisfactory appearance of the flaps.

Precise repair of small joint defect of hand with free second metatarsophalangeal joint tissue flap based on digital technology / 中华显微外科杂志

Objective:To explore the clinical effect of repairing interphalangeal joint defect of hand with free transfer of part of the 2nd metatarsophalangeal joint tissue flap precisely cut with the aid of digital 3D printing technology.Methods:From December 2016 to December 2020, 7 patients with partial joint defects of proximal interphalangeal joints of fingers were treated in Department of Hand and Foot Surgery, Shunde Hospital Affiliated to Guangzhou Medical University(Foshan Shunde Lecong Hospital). Before surgery, three-dimensional data of hand and foot bones were collected, and the 3D printing model was used to simulate the operation in vitro. During the operation, the first dorsal metatarsal artery-the 2nd dorsal metatarsal artery was used as the pedicle, and the 2nd metatarsophalangeal joint composite tissue flap with a required size was harvested with the assistance of the navigation template to tranfer and repair the small joint defects of hand. All 7 cases entered follow-up at outpatient and telephone. Results:All 7 cases survived. Postoperative follow-up was 3-24(mean 9.5) months, Range of motion of the repaired interphalangeal joint was (56 ± 6)°; According to the Evaluation Standard of Thumb and Finger Reconstruction Function of the Society of Hand Surgery of the Chinese Medical Association, 2 cases were excellent, 4 cases were good, and 1 case was poor.Conclusion:Transfer of the free 2nd metatarsophalangeal joint tissue flap assisted by 3D printing technology in repair of the small joint defect of the hand can accurately harvest the tissue flap, which is clinically reliable.

3D printing-assisted pre-fenestration and branch stent endovascular repair for the treatment of thoracoabdominal aortic aneurysms / 中华普通外科杂志

Objective:To evaluate the safety and efficacy of 3D printing-assisted pre-fenestration and branch stent endovascular repair (F/b EVAR) in the treatment of thoracoabdominal aortic aneurysms.Methods:The clinical data of 26 patients treated with 3D printing-assisted F/b EVAR for complicated thoracic and abdominal aortic diseases at the Department of Vascular Surgery, the Ninth People's Hospital,Shanghai Jiaotong University School of Medicine from May 2019 to Sep 2022 were retrospectively analyzed.Results:The success rate in these 26 cases of TAAA with 3D printing combined with F/b EVAR was 97.89%, and the mean follow-up time was (8.03±4.15) months. Four cases had Ⅲc internal leakage and disappeared during the follow-up. One case of type Ⅲ leakage were narrowed during follow-up. Ic type internal leakage occurred in 1 patient and disappeared after the addition of a stent at the distal end. During the follow-up period, aortic CTA indicated that 1 patient had renal artery stent occlusion and smooth blood in other visceral branches. No complications such as organ ischemia, lower limb ischemia and all-cause death occurred during follow-up.Conclusion:3D printing-assisted F/b EVAR minimally invasive repair of TAAA is a feasible, effective and safe technique, with high success rate and low complication rate of visceral branch artery reconstruction.

The treatment of 3D-printed metal prostheses on bone defect of malignant bone tumors in lower limbs / 中华骨科杂志

Objective:To investigate the early and middle term clinical efficacies of 3D-printed metal prostheses in the reconstruction of bone defects after osteotomy in malignant bone tumors.Methods:A total of 34 patients with malignant bone tumors of lower extremity femur and tibia who underwent 3D printing individualized metal prosthesis replacement surgery in the Department of Bone and Soft Tissue of Affiliated Cancer Hospital of Zhengzhou University from March 2019 to March 2022 were retrospectively analyzed. There were 23 males and 11 females, with an average age of 19.1±15.2 years (range, 7-80 years). There were 22 children and adolescents younger than 18 years old. There were 3 cases in the proximal femur, 15 cases in the middle and distal femur, 10 cases in the proximal tibia and 6 cases in the distal tibia. According to the final pathological diagnosis, 24 cases of osteosarcoma, 6 cases of Ewing's sarcoma, 2 cases of undifferentiated sarcoma, 1 case of osteosarcoma, and 1 case of malignant giant cell tumor of bone were enrolled in this study. Postoperative complications, wound healing, periprosthetic fracture and aseptic loosening, tumor outcome (evaluated by tumor control evaluation criteria), and length difference of lower limbs were recorded. Response evaluation criteria in solid tumor (RECIST) was used to evaluate tumor outcomes. Prosthetic-bone interface healing was evaluated postoperatively, and the function was evaluated based on Musculoskeletal Oncology Society (MSTS) 93.Results:The length of lesions was 70-240 mm in 34 patients, with an average of 125.5±35.4 mm. The length of osteotomy was 80-275 mm, with an average of 160.2±33.9 mm. No tumor was found on the osteotomy surface. The customized prosthesis was firmly installed and closely matched with the side of the preserved articular surface. There were 2 patients with local incision fat liquefaction and 4 patients with superficial wound infection, which healed after debridement and antibiotic treatment. One distal tibia osteosarcoma case developed severe periprosthetic infection 2 months after surgery, resulting in prosthesis implantation failure, limb movement pain and poor ankle function. After removal of the prosthesis, infection control and osteogenesis with the Ilizarov technique, the infection was completely controlled and local osteogenesis was possible. The remaining 33 patients had a good prosthetic-bone interface union. One case was found to have localized bone resorption on the contact surface of the prosthesis 7 months after operation, but the metal prosthesis and screws were not loose. The incisions healed well in other patients, without infection, prosthesis loosening, fracture or other complications. All patients survived and were followed up for 13.8±5.6 months (range, 7-27 months). During the follow-up, there was no recurrence of tumor at the osteotomy end in all patients, but 5 patients developed lung metastasis. At the end of the last follow-up, all patients survived. Among them, 16 patients had unequal length of lower limbs, including 10 cases within 2 cm, 3 cases between 2-5 cm, and 3 cases over 5 cm. With the exception of one patient whose prosthesis was removed due to infection, the MSTS 93 of the other patients was 24.9±2.2 (range, 19-28), and were rated as excellent in 26 cases and good in 7 cases. According to the RECIST evaluation criteria, 26 of 34 patients had complete response, 5 had disease progression, and 3 had stable disease.Conclusion:3D printed metal prosthesis is one of the effective methods for the treatment of bone defects after resection of malignant bone tumors in lower limbs, which is safe, reliable and has satisfactory early curative effect.

Value of 3D printed polyether ether ketone prosthesis in the treatment of scapular tumors / 中华骨科杂志

Polyetheretherketone (PEEK) as a new type of thermoplastic engineering plastic, has good biological activity, elastic modulus close to human cortical bone and radiation permeability, and has been widely used in medical field. This study aims to explore the safety and clinical efficacy of using 3D printing personalized PEEK materials to repaire scapular bone defects after bone tumor resection. A total of 6 patients who underwent the implantation of 3D printed PEEK scapular prosthesis from January 2020 to December 2021 in Yunnan Cancer Hospital were retrospectively analyzed. There were 3 males and 3 females, with age ranged from 14 to 52 years. There were 1 case of synovial sarcoma, 1 of Ewing's sarcoma, and 4 of chondrosarcoma. PEEK prosthesis was designed and fabricated based on CT data before surgery. Tumor resection and prosthesis replacement were performed under the premise of ensuring safe surgical boundaries, including 2 cases of total scapular prosthesis replacement and 4 cases of partial scapular prosthesis replacement. The operation time was 90-170 min, and the intraoperative blood loss was 100-400 ml. All 6 patients received satisfactory follow-up, with a tumor progression free survival time of 16-28 months. No tumor recurrence or metastasis was observed, and all patients survived tumor free. At last follow-up, the Constant-Murley shoulder joint score was a minimum of 62 points and a maximum of 68 points. The Japanese Orthopaedic Association's shoulder joint score was 63 points minimum and 78 points maximum. Computer-aided design 3D printing PEEK material prosthesis has certain advantages in the treatment of scapular tumor limb salvage. It has light weight, well adapted, relatively simple installation, good histocompatibility, and can obtain a better appearance and function of the shoulder joint after operation. It can become one of the options for limb salvage treatment of scapular tumor.

Assessment of 3D-printed tissue compensators for superficial tumor X-ray radiation compensation / 中华放射医学与防护杂志

Objective:To investigate the advantage of three dimensional(3D)-printed tissue compensators in radiotherapy for superficial tumors at irregular sites.Methods:A subcutaneous xenograft model of prostate cancer in nude mice was established. Mice were randomly divided into no tissue compensator group( n=6), common tissue compensator group( n=6), and 3D-printed tissue compensator group( n=6). Computed tomography (CT) images of nude mice in the 3D-printed tissue compensator group were acquired. Compensator models were made using polylactic acid, and material properties were evaluated by measuring electron density. CT positioning images of the three groups after covering the corresponding tissue compensators were acquired to delineate the gross tumor volume (GTV). Nude mice in the three groups were irradiated with 6 MV X-rays at the prescribed dose. The prescribed dose for the three groups was 1 500 cGy. The dose distribution in the GTV of the three groups was calculated and compared using the analytical anisotropic algorithm in the Eclipse 13.5 treatment planning system. The metal-oxide-semiconductor field-effect transistor was used to verify the actual dose received on the skin surface of nude mice. Results:The air gap in the 3D-printed tissue compensator group and the common tissue compensator group was 0.20±0.07 and 0.37±0.07 cm 3, respectively ( t=4.02, P<0.01). For the no tissue compensator group, common tissue compensator group, and 3D-printed tissue compensator group, the D95% in the target volume was (1 188.58±92.21), (1 369.90±146.23), and (1 440.29±45.78) cGy, respectively ( F=9.49, P<0.01). D98% was (1 080.13±88.30), (1 302.76±158.43), and (1 360.23±48.71) cGy, respectively ( F=11.17, P<0.01). Dmean was (1 549.08±44.22), (1 593.05±65.40), and (1 638.87±40.83) cGy, respectively ( F=4.59, P<0.05). The measured superficial dose was (626.03±26.75), (1 259.83±71.94), and (1 435.30±67.22) cGy, respectively ( F=263.20, P<0.001). The percentage variation in tumor volume growth after radiation was not significantly different between the common tissue compensator group and the 3D-printed tissue compensator group ( P>0.05). Conclusions:3D-printed tissue compensators fit well to the body surface, which reduces air gaps, effectively increases the dose on the body surface near the target volume, and provides ideas for radiotherapy for superficial tumors at some irregular sites.

3D-PCT-assisted CT-guided radioactive particle implantation precision / 中华放射医学与防护杂志

Objective:To study the precision of 3D printing coplanar template (3D-PCT) assisted CT-guided radioactive particle implantation using two types of phantoms, and compare the differences between the phantoms, in order to provide reference for radioactive particle implantation.Methods:The needle inserting path was designed in the brachytherapy treatment planning system (BTPS) and the needle tip coordinates were obtained. Following the needle inserting path, the implant needles were inserted into the custom and the liver phantoms, respectively. Then gold markers were implanted through the needles. Subsequently, the needles were withdrawn by 10 mm, and the cold sources were implanted. The coordinates of needle tips, gold markers, and cold sources were recorded. The precision of implanted needles, first particles, and particles after needle withdrawal were obtained by calculating the distance between two points in the space. Finally, the differences between the two phantoms were compared through independent samples t-test. Results:In the 3D-PCT-assisted CT-guided radioactive particle implantation, the precision of implanted needles, first particles, and particles after needle withdrawal in the custom and the liver phantoms was (1.89±0.72) and (2.14±0.88 ) mm ( P>0.05), (2.03±1.14) and (2.42±1.12) mm ( P>0.05), and (-1.96±1.29) and (-2.82±0.91) mm ( t=2.09, P=0.046), respectively. Conclusions:The 3D-PCT-assisted CT-guided radioactive particle implantation is efficient, stable, and precise, showing slight precision differences between the two phantoms.

Advances in 3D printing-based body membrane immobilization technology in radiotherapy / 中华放射医学与防护杂志

The widespread application of 3D printing and computer technologies in the medical field has opened up opportunities for digital and automated fabrication of body immobilization tools for radiotherapy, thus making it possible to get rid of the original complex manual fabrication process. As the most widely used technique for body immobilization, body membrane immobilization has always attracted much attention. This review outlines the development of the body membrane immobilization technology in different radiotherapy stages. Moreover, the advances in the application of 3D-printed body membranes were introduced, as a development direction of body immobilization technology, in the field of radiotherapy. This technology can be utilized as a reference for clinical application and research.