Intraoperative 2D C-arm and 3D O-arm in children: a comparative phantom study.

Exposure to ionizing radiation is a concern for children during intraoperative imaging. We aimed to assess the radiation exposure to the paediatric patient with 2D and 3D imaging. To evaluate the radiation exposure, patient absorbed doses to the organs were measured in an anthropomorphic phantom representing a five-year-old child, using thermoluminescent dosimeters. For comparative purposes, organ doses were measured using a C-arm for one minute of fluoroscopy and one acquisition with an O-arm. The cone-beam was centred on the pelvis. Direct and scattered irradiations were measured and compared (Student's <i>t</i> -test). Skin entrance dose rates were also evaluated. All radiation doses were expressed in µGy. Direct radiation doses of pelvic organs were between 631.22 and 1691.87 for the O-arm and between 214.08 and 737.51 for the C-arm, and were not significant (p = 0.07). Close scattered radiation on abdominal organs were between 25.11 and 114.85 for the O-arm and between 8.03 and 55.34 for the C-arm, and were not significant (p = 0.07). Far scattered radiation doses on thorax, neck and head varied from 0.86 to 6.42 for the O-arm and from 0.04 to 3.08 for the C-arm, and were significant (p = 0.02). The dose rate at the skin entrance was 328.58 µGy.s <sup>-1</sup> for the O-arm and 1.90 with the C-arm. During imaging of the pelvis, absorbed doses for a 3D O-arm acquisition were higher than with one minute fluoroscopy with the C-arm. Further clinical studies comparing effective doses are needed to assess ionizing risks of the intraoperative imaging systems in children

Unexpected case of ankle tuberculosis in a young professionals leading to delay in diagnosis

We report a case of a 38 year-old engineer presented with left ankle pain for 2 years and initially treated as gouty arthritis because of high serum uric acid. A year later his left ankle become swollen and plain radiograph showed soft tissue swelling around the ankle with normal articular surface and bone. An MRI investigation reported as gouty arthritis of ankle with tophi. While on treatment for gouty arthritis, he developed pus discharge from the swelling. The ankle pain also worsen and he was unable to weight bear on the affected leg. An incision and drainage shown pus from the ankle joint which grew pseudomonas aeruginosa. He was treated with intravenous followed by oral ciprofloxacin 250 mg bd. However his condition does not improved and a month after antibiotic treatment a repeated radiograph shows narrowing of joint space with irregular cortical destruction, osteopenic bone . suggestive of worsening of his septic arthritis. During this period he deny of having any fever, cough or night sweats. However he did notice some loss of weight and loss of appetite. He has worked in Africa and Russia before in petroleum industry. After 4 months of antibiotic and no sign of improvement, a biopsy and repeat culture was taken from the ankle which reveal tuberculous arthritis and positive for AFB culture. A plain chest radiograph revealed miliary tuberculosis picture. He was started on a anti TB treatment and the wound healed after a few weeks. After 4 months of treatment he was able to walk without support with reduce ankle range of motion. This case illustrate that the diagnosis was delay because tuberculosis was not suspected in a young professionals with ankle pain and elevated serum uric acid level. Further delay in diagnosis because MRI report also suggestive of gouty tophi and the pus culture and sensitivity grew pseudomonas aeruginosa

Hip deformities and femoroacetabular impingement

RESUMO: Conceptualmente, a conservação de uma estrutura anatómica é mais benéfica do que a sua substituição. No caso das articulações humanas, este conceito é particularmente importante face aos múltiplos problemas, ainda não resolvidos, relacionados com próteses e materiais usados na cirurgia ortopédica. Na articulação coxofemoral, o conceito de preservação, melhorando os parâmetros biomecânicos, assume uma complexidade técnica acrescida maioritariamente pelo facto de a circulação epifisária do fémur ser intra-articular e dada a proximidade de importantes estruturas neurovasculares. O conflito femoroacetabular (CFA) e a displasia acetabular no adulto jovem, são duas entidades patológicas comuns embora com múltiplas áreas ainda por investigar. A displasia infantil, não diagnosticada e não tratada, pode originar displasia acetabular residual na idade adulta e consequente sintomatologia e limitação funcional. O diagnóstico de CFA no adulto é baseado em critérios clínicos e radiográficos. Clinicamente apresenta-se igualmente com dor e limitação funcional. Radiologicamente, dois subtipos de CFA são habitualmente reconhecidos, o tipo Cam (mecanismo patológico decorrente de asfericidade femoral) e o tipo Pincer (por hipercobertura acetabular). Embora com padrões diferentes de envolvimento articular, os dois mecanismos de conflito condicionam dor, lesão estrutural do labrum e condropatia. Atualmente, a morfologia Cam é considerada como um dos principais fatores de risco morfológico que contribuem para o desenvolvimento de osteoartrose precoce da coxofemoral, eventualmente com necessidade de recurso a prótese total da anca. Apesar de a investigação inicial na área da cirurgia conservadora da anca ter documentado bons resultados cirúrgicos, atualmente a controvérsia é francamente superior ao consenso relativamente à melhor abordagem diagnóstica e terapêutica. Caracteristicamente, apesar de em muitos casos os achados clínicos e radiológicos serem inequívocos para o diagnóstico de CFA, um número substancial de doentes apresenta achados frustes ou equívocos. Por outro lado, múltiplos estudos descreveram uma alta prevalência de morfologia compatível com CFA na população adulta e em indivíduos saudáveis assintomáticos. Atualmente, não existe uma ferramenta de imagem ideal que facilite a alocação fidedigna de todos os doentes a um grupo patológico específico ou, por outro lado, exclua com confiança o diagnóstico de conflito. No entanto, os parâmetros de imagem podem ser utilizados para analisar e descrever as diferentes características morfológicas da anca e adicionalmente confirmar o diagnóstico de CFA. Esta tese enfoca, por um lado, a avaliação da morfologia coxofemoral em diferentes populações, investigando quais articulações estão mais predispostas ao desenvolvimento de sintomas e, por outro, os resultados do tratamento cirúrgico de uma coorte com o diagnóstico de CFA tipo Cam. Especificamente, a investigação efetuada: 1) examinou características morfológicas específicas da coxofemoral em diferentes populações (sintomáticas ou não sintomáticas); 2) desenhou um modelo estatístico baseado em preditores anatómicos no sentido de estabelecer as articulações em risco de desenvolvimento sintomático, incorporando geometrias articulares específicas e parâmetros espinhopélvicos; e 3) analisou os resultados de terapêutica cirúrgica numa coorte de doentes com o diagnóstico CFA tipo Cam. Durante a progressão clínica na área da imagiologia e nesta área patológica em particular, apercebemo-nos da existência de múltiplas lacunas de conhecimento que procurámos colmatar com a investigação agora publicada e descrita nesta tese. A sistematização por capítulos reflete precisamente a necessidade de abordar a questão em áreas de conhecimento, simultaneamente distintas e complementares. Os seis capítulos desta tese abrangem o espectro clínico desde o diagnóstico até ao tratamento da anca jovem. De modo a apresentar os objetivos desta tese numa sequência lógica, desde a anatomia geral até à morfologia e tratamento específicos do CFA, a análise da anca assintomática será descrita em primeiro lugar seguida pela análise da relação anatomoclínica entre morfologia articular e sintomas. Por último será abordada a terapêutica do doente sintomático. Na PARTE I, apresentamos os tópicos essenciais para compreender a abrangência do espectro da presente tese, designadamente a relevância e a contemporaneidade do tema “CFA” e adicionalmente o enquadramento anatómico, morfológico e vascular desta articulação. O Capítulo 1 é dedicado ao desenvolvimento e morfogénese da anca. No Capítulo 2, sublinhamos a importância e o papel da imagem através de uma revisão enfocada nas perspetivas atuais e futuras sobre este tópico (Artigo I). No Capítulo 3, realizamos uma revisão sistemática da literatura no sentido de descrever o estado da arte com foco na prevalência da morfologia de CFA em populações assintomáticas e sintomáticas. Este capítulo destaca as múltiplas lacunas de conhecimento relativas ao papel da morfologia da articulação coxofemoral na patogénese do CFA (Artigo II). Com base nesta parte introdutória, abordamos seguidamente os objetivos da presente tese, gerais e específicos, na PARTE II.Na PARTE III, descrevemos o corpo da investigação clínica original efetuada. O Capítulo 4 é dedicado à caracterização detalhada da morfologia da anca, designadamente óssea e vascular. A morfologia coxofemoral foi quantificada utilizando software com capacidade de semi-automatização analítica, permitindo estudar a prevalência e relação entre as diferentes morfologias articulares e o género, dominância e simetria articular (Artigo III). A morfologia Cam foi ainda alvo de caracterização mais aprofundada, através do desenvolvimento de um novo parâmetro quantitativo com potencialidade diagnóstica e de planeamento cirúrgico/ /prognóstico, primariamente testado numa coorte assintomática (Artigo IV) e seguidamente também em doentes com indicação cirúrgica (Artigo V). Na nossa atividade clínica diária apreciámos a necessidade urgente de melhor caracterizar a topografia da deformidade Cam e a respetiva relação com as artérias nutritivas da epífise femoral. A impressão clínica referida sugeria que a morfologia Cam frequentemente se estendia posteriormente ao quadrante póstero-superior, intersectando a região retinacular vascular. No entanto, por imagem a natureza arterial destas estruturas nunca havia sido confirmada. Por esta razão, a importância do parâmetro mencionado foi sublinhada e comprovada no estudo cadavérico com avaliação topográfica vascular do fémur proximal (Artigo VI). No Capítulo 5 testámos múltiplos parâmetros imagiológicos e respetivas variações/relações com diferentes morfologias coxofemorais, no sentido de identificar as articulações com risco clínico aumentado de desenvolvimento sintomático. Para este fim efetuámos estudos baseados em computação avançada com modelação estatística (Artigo VII) e também em ressonância magnética (RM) tridimensional (Artigo VIII). O Capítulo 6 descreve as opções de tratamento (Artigo IX) e os resultados clínicos num estudo clínico de uma coorte com follow-up mínimo de 2 anos, comparando a abordagem cirúrgica aberta e artroscópica (Artigo X). Os resultados dos diferentes capítulos estão sumarizados na PARTE IV, onde apresentamos a síntese geral, a discussão crítica dos resultados obtidos à luz da literatura atual e finalmente as conclusões relevantes. As oportunidades futuras de investigação são igualmente abordadas neste capítulo. Em resumo o trabalho constante da presente tese sugere: Primeiro, que a avaliação imagiológica detalhada da morfologia coxofemoral é essencial no sentido de compreender aprofundadamente não só a própria articulação como também a morfologia pélvica (Artigo I). Segundo, paradoxalmente, a definição clínica de um caso patológico e das diferentes entidades relacionadas, é ainda inexistente. Os parâmetros quantitativos e qualitativos que comummente estão associados com CFA tipo Pincer e Cam são francamente frequentes em diferentes populações (sintomáticas e assintomáticas) (Artigo II).Terceiro, em populações assintomáticas adultas, os intervalos de referência específicos para os parâmetros quantitativos associados a morfologia de CFA e displasia são mais latos e com limites superiores mais elevados do que os atualmente utilizados na prática clínica (Artigo III). A morfologia femoral bem como os epicentros/magnitudes das deformidades Cam são específicos de género, observando-se maiores valores de ângulo alfa e ómega em indivíduos do sexo masculino (Artigo IV). Quarto, é frequente a interseção entre a extensão póstero-superior da deformidade Cam e a convergência epifisária das estruturas vasculares retinaculares observadas em RM, aspetos que se revestem de primordial importância no planeamento cirúrgico. Adicionalmente a extensão radial da deformidade Cam (ângulo ómega) está significativamente mais relacionada com a sintomatologia clínica pré-cirúrgica do que o parâmetro mais comummente utilizado na prática clínica (ângulo alfa) (Artigo V). A origem das estruturas vasculares observadas por RM na prega retinacular é inequivocamente arterial, sendo que abrange uma extensão mais anterior do que classicamente assumido (Artigo VI). Quinto, as geometrias ovalares (em detrimento das morfologias esféricas e elipsoides) são melhor representativas de ambas as superfícies articulares da coxofemoral, designadamente do fémur e acetábulo, bem como das ancas sintomáticas que clinicamente exibem sinais de CFA (Pincer, Cam e misto) (Artigo VII). Indivíduos com maiores deformidades Cam, aspetos de hipocobertura acetabular e acentuação da anteflexão pélvica apresentam uma maior probabilidade de desenvolverem sintomas articulares (Artigo VIII). Esta observação é crítica, dado que fornece, na prática clínica, informação essencial acerca da potencial predisposição para fenómenos de exacerbação sintomática futura, permitindo desta forma instituição de medidas terapêuticas/preventivas adequadas. Na perspetiva do doente, um diagnóstico precoce e preciso, pode conceptualmente prevenir, numa primeira fase, alterações condropáticas articulares e, numa segunda instância, progressão para artrose estabelecida. Sexto, documentamos resultados clínicos e funcionais significativamente favoráveis quando comparamos a abordagem artroscópica e aberta no tratamento cirúrgico da deformidade Cam, sendo de observar que o género feminino está associado a menor score funcional na avaliação pré-operatória (Artigos IX e X). Futuramente, a imagiologia e a cirurgia conservadora da anca irão desenvolver-se conjuntamente e em paralelo com novos e maiores desafios. A descrição de novos parâmetros analíticos para avaliação da patoanatomia coxofemoral, associada à inovação tecnológica crescente e à implementação da inteligência artificial, impõem uma evolução clínica oposta à assunção de classificações patológicas demasiadamente simplistas. Nesse sentido a existência de guidelines de diagnóstico e terapêutica mais efetivas e baseadas na evidência, que nos levem além da pura diferenciação entre CFA e displasia, são urgentes. A história natural das deformidades Cam e Pincer, sintomáticas ou assintomáticas, é ainda grandemente desconhecida, assumindo-se como uma área determinante de investigação no que concerne ao diagnóstico, terapêutica e prognóstico.ABSTRACT: Conceptually, the preservation of a human anatomical structure makes more sense than its replacement. This concept is even more striking in the case of human joints due to the multitude of unsolved problems related to implants used in orthopaedic surgery. With respect to the hip, joint preservation assumes an increased technical complexity when compared to other joints; this is due to two main reasons: the intra-articular epiphyseal circulation of the femur and the proximity of large neurovascular structures. Femoroacetabular impingement (FAI) and acetabular dysplasia (DHD) in young adults are two common but poorly characterised pathological entities. If undiagnosed and untreated, dysplasia in childhood may lead to residual DHD in young adults, as diagnosed on radiographs, and may also give rise to symptoms such as hip pain and restricted range of motion. The diagnosis of FAI in adults is based on clinical and imaging criteria. The most frequently noticed symptoms of FAI include hip pain and restricted function. Radiologically, two main subtypes of FAI are recognised: The Cam-type, with the pathoanatomical mechanism located on the femoral side, and the Pincertype on the acetabular side. Although with different pathological patterns, both types cause pain and articular damage of the labrum and cartilage. While Cam-type FAI is believed to be a major contributing factor to the early onset of hip osteoarthritis (OA), which eventually requires a total hip replacement, the relationship of other shapes and morphologies with OA are still under debate. Despite the initial promising reports on outcomes following surgical management of these conditions, the best approach to diagnose and manage them still remains controversial. Although for some patients there are unambiguous clinical and imaging findings of FAI, for a substantial number of patients there are minimal or intermediate findings. Moreover, several studies have reported a high prevalence of FAI morphology among the “normal” population and in asymptomatic healthy individuals. At present, there is no adequate imaging tool to facilitate the reliable allocation of all patients into the correct diagnostic group or to confidently rule out diagnosis. However, imaging parameters can be used to describe different hip morphological characteristics and additionally confirm or preclude the diagnosis of FAI.This thesis focuses on assessing hip morphology in different populations by investigating which specific joints are more prone to developing symptoms and by evaluating treatment outcomes of a FAI cohort. Specifically, this research concentrates on the following: 1) examining population-specific (symptomatic and non-symptomatic) characteristics of hip morphology; 2) developing an anatomic-based model to establish “at-risk” hip joints, incorporating subject-specific hip geometries and spinopelvic parameters and 3) investigating treatment outcomes in a Cam-type FAI cohort. In our clinical progression in imaging and in this particular area of pathology, we became aware of the existence of several gaps that we sought to fill with the now published research hereby described. The systematisation by chapters precisely reflects the need to address the issue in simultaneously distinct and complementary areas of knowledge. This thesis consists of six chapters, which cover the entire spectrum from the diagnosis to treatment of the young hip. To present the aims of this thesis in a sequential manner from general morphology to more specific FAI-related topics, the analysis of the asymptomatic hip will be presented first, followed by how joint morphology is associated with symptoms and, finally, will conclude with treatment. In PART I, we introduce the topics that are relevant to understand the full scope of our thesis; we aim to accomplish this by addressing the relevance and contemporariness of the “FAI” theme and by describing the general and vascular anatomy of the hip. Chapter 1 is devoted to hip development and morphogenesis. In Chapter 2, we address the importance of imaging by conducting a thorough review of current and future perspectives on this topic (Paper I). In Chapter 3, we perform a systematic review of the literature to write a state-of-the-art overview, focussing on asymptomatic and symptomatic FAI morphology prevalence and highlighting the multiple gaps in knowledge regarding the role of hip morphology in the pathogenesis of FAI (Paper II). Building on the first part, we address the rationale and aims of this thesis in PART II. In PART III, we describe the original research that was performed and published. Chapter 4 focusses on the detailed characterisation of hip morphology, both osseous and vascular. Bony hip morphology was quantified using a semi-automated software, which allows to robustly study in detail shape variants in an asymptomatic population and their relationship with sex, side and limb dominance (Paper III). Cam morphology was further defined by developing a novel quantitative parameter, with diagnostic and treatment planning capabilities using a cohort of both asymptomatic individuals (Paper IV) and patients undergoing surgery (Paper V). Moreover, we felt the need to better characterise the topography of the deformity and its relationship with the nourishing arteries of the femoral head, as Cam morphology frequently has a posterior a bstr extension that overlaps the retinacular vascular structures. However, its arterial origin has never been described or confirmed in the literature. For this reason, the importance of the aforementioned parameter has been outlined by the cadaveric arterial topographic study of the proximal femur (Paper VI). In Chapter 5, we test multiple parameters and their associated shape variants to detect which ones allow identifying a risk-increased joint in various populations. To this end, we use both advanced computing for shape modelling (Paper VII) and three dimensional (3D) magnetic resonance imaging (MRI) (Paper VIII). Chapter 6 describes the various treatment options (Paper IX) and outcomes in a cohort clinical study, comparing open surgery with arthroscopic surgery in terms of treating Cam deformities (Paper X). The results of the aforementioned chapters are summarised in PART IV, presenting the general synthesis, discussing the results in the light of current literature and detailing the conclusions of this thesis. The scope of potential future research within this field is also presented in this chapter. In brief, this thesis suggests the following: First, detailed imaging assessment of hip morphology is paramount to better understanding both the hip joint and pelvic morphology (Paper I). Second, the case definitions of different morphologies and clinical entities are missing as far as FAI and related disorders are concerned. Qualitative and quantitative radiographic findings thought to be associated with Cam- and Pincer-type FAI, as well as the coexistence between them, are quite common among different populations (Paper II). Third, in adult asymptomatic populations, sex-specific reference intervals for hip measurements for DHD and FAI morphology are wider than currently accepted values (Paper III). Moreover, femoral morphology with distinct Cam magnitudes and epicentres is also sex-specific, with higher mean alpha angle (α°) and omega angle (Ω°) values seen in males (Paper IV). Forth, Cam deformity frequently overlaps with the retinacular vascular structures seen in an MRI; this finding has practical surgical relevance. Additionally, the radial extension of the Cam deformity (Ω°) is more significantly associated with the patients’ symptoms prior to surgery than the α° (paper V). The origin of the vascular structures seen in the retinacular fold is unequivocally arterial in nature, and these structures have a more anterior distribution than classically assumed (Paper VI). Fifth, ovoid geometries are more representative of both articular surfaces of the hip joint as well as of Cam, Pincer and mixed impinged hips when compared to spherical or ellipsoidal shapes (Paper VII). Individuals with larger Cam deformities, decreased acetabular coverage and increased pelvic anteflexion are more likely to experience hip symptoms (Paper VIII). This provides clinicians with indications of how the pathology exacerbates, allowing them to perform the correct clinical assessments and proceed with the correct form of care. From a patient’s perspective, an early and accurate diagnosis could prevent cartilage degradation and progression to OA. Sixth, similar outcomes and significant functional improvement are observed when comparing open and arthroscopic surgery in the treatment of Cam deformities (follow-up time of two years). It should be noted that the female gender was associated with poor hip function in the preoperative evaluation (papers IX and X). Looking ahead, imaging and hip preserving surgery (HPS) will evolve hand-in-hand in the face of new and greater challenges. The increasing number of analytic parameters describing hip joint pathomorphologies as well as new sophisticated 3D imaging-analysis together with emerging artificial intelligence-based technologies have transported us beyond simple classification systems. Moreover, more reliable diagnostic and treatment guidelines that go beyond differentiation into pure FAI and dysplasia are paramount. The largely unknown natural course of both hips with symptomatic FAI and asymptomatic individuals continues to present research opportunities as far as diagnosis, treatment and prognosis are concerned

Pelvic kinematics as confounding factor for cam hip impingement

The purpose of this thesis was to explore a range of biomechanical factors linked to the development of symptoms and potentially early onset hip OA in people with cam hip impingement. This was achieved through shape analysis on 3D bone models (segmented from medical images), and motion analysis performed during walking and squatting. Following ethical approval, kinematic and morphological variables were obtained from 19 pre-operative hip impingement patients and 18 healthy controls, and these were compared between groups. Patients demonstrated reduced neck-shaft-angles (-6.0°, p<.01) and increased anterior pelvic tilt during gait (+3.2°, p=.04) which are thought to predispose to impingement by decreasing the proximity between the cam and acetabular rim and making abutment more likely. The transverse pelvic plane is used to measure pelvic tilt during motion analysis, it is therefore interesting that the angle between the transverse and anterior pelvic plane is increased (+4.6°, p=.03) in patients, emphasising that the interplay between shape and function is a priority for further research. Avoidance of hip extension (-5.9°, p<.01) was also observed, which could be a compensatory mechanism to prevent further damages to the hip. Furthermore, large cams are thought to act as a mechanical constraint and limit rotation movement allowed within the acetabulum, as demonstrated by reduced peak hip internal rotation (during squat, -8.5°, p=.03). Controls were regrouped based on morphology to allow comparison between asymptomatic (CAM-; n=11) and symptomatic (CAM+, n=16) cams. Symptomatic cams have an increased width (+41.4°, p<.01), and start more superiorly (-29.4°, p<.01). Increased sagittal pelvic mobility (e.g. during a squat; -11.2° for CAM+, p<.01) is thought to be protective against hip impingement symptoms, as during high flexion angles the pelvic tilts backwards reducing the risk of abutment. These findings highlight the need to establish thresholds taking confounding factors into account.Open Acces

Impresión 3D en Cirugía Ortopédica y Traumatología. Revisión sistemática de su aplicabilidad y estudio de los métodos de esterilización más adecuados para la utilización en quirófanos de las impresiones realizadas en el hospital.

Introduction In-Hospital 3D printing has been broadly developed since the end of the addictive manufacturing patents. However, although there are many printing technologies, the most frequent in our field are Fused Deposition Modelling (FDM) and Stereolithography (SLA), which usually use hollow infill patterns in order to save time and material. It is common to use these models and surgical guides in the operating room, however, there were no publications warranting an adequate sterilization of the in-house prints. Objectives To describe systematically all the current applications of in-hospital 3D printing up to date and to run an experimental study which demonstrates the sterilization of the inside of our anatomical models and surgical guides. Material and Methods A systematic review was made on PubMed to obtain all the published articles regarding this topic up to December 2021. Those publications in other language (not in English or Spanish) or describing industrial applications, cell therapies, pharma therapies or involving human specimens were rejected. A record card was made for each application to make further search easier. For the experimental study, a total of 24 cylinders were designed and printed with a 3D printer in Polylactic Acid (PLA) with an infill density of 12%. Manufacturing was paused when 60% of the print was reached and 20 of the cylinders were inoculated with 0.4 mL of a suspension of S epidermidis ATTCC 1228 in saline solution at turbidity 1 McFarland. Printing was resumed, being all the pieces completely sealed with the inoculum inside. Posteriorly, 4 groups were made according to the chosen sterilization method: Ethylene Oxide (EtO), Gas Plasma, Steam Heat or non-sterilized (positive control). Each group included 5 contaminated cylinders and 1 non-contaminated cylinder as a negative control. After sterilization, the inside of the cylinders was cultured during 7 days. Results We obtained a total of 1193 articles in the research, of which 298 articles met the inclusion criteria, finding a total of 143 applications which are summarized as record cards. In the sterility study, we observed bacterial growth of just a few Forming Colony Units (FCU) in 4 out of 5 positive controls and in 2 out of 5 contaminated cylinders sterilized with Gas Plasma. We could not assess any bacterial growth in any of the EtO or Steam Heat samples or in any of the negative controls. Pieces sterilized under Steam Heat resulted completely deformed. Conclusions There are multiple applications for in-house 3D printing in the field of orthopaedics. High temperatures reached during the procedure of additive manufacturing can decrease the bacterial load of the biomodels. However, there is a potential risk of contamination during the proce- dure. We recommend sterilization with EtO for in-hospital 3D-printed PLA hollow biomodels or guides. Otherwise, in case of using Gas Plasma, an infill of 100% should be applied.Introducción La impresión 3D hospitalaria ha cobrado un gran impulso desde la liberalización de las patentes sobre la fabricación aditiva. Aunque existen multitud de tecnologías de impresión, las más frecuentes en nuestro medio son la impresión por deposición de material fundido (FDM) y la impresión estereolitográfica (SLA), las cuales, suelen recurrir a patrones de relleno incompletos para ahorrar tiempo y material. Aunque es frecuente la utilización de biomodelos y guías quirúrgicas obtenidas por este medio en los quirófanos, no existían hasta la fecha estudios que garantizasen una adecuada esterilidad de los mismos. Objetivos Realizar una descripción sistematizada de todas las aplicaciones descritas de la impresión 3D hospitalaria hasta la fecha y hacer un estudio experimental que demuestre la capacidad esterilizante del interior de nuestros biomodelos y guías quirúrgicas. Material y Métodos Se realiza una revisión sistemática en PubMed para obtener todos los artículos publicados sobre el tema hasta diciembre de 2021, descartándose aquellos en otro idioma o que tratan sobre aplicaciones industriales, celulares, farmacológicas o experimentales en cadáver. Se realiza una ficha de cada una de las aplicaciones para facilitar su posterior consulta. Por otro lado, realizamos un estudio experimental con 24 cilindros impresos en ácido poliláctico con una densidad de relleno del 12%. La fabricación se detuvo cuando se alcanzó el 60% de la impresión y 20 de los cilindros se inocularon con 0.4mL de una suspensión de S epidermidis ATTCC 1228 en solución salina con una turbidez de 1 McFarland. Tras la inoculación, se continuó la impresión quedando las piezas completamente selladas con el inóculo en su interior. Posteriormente, se crearon 4 grupos de acuerdo con el método de esterilización empleado (Óxido de etileno, Gas plasma, Autoclave y grupo control positivo, sin esterilizar). Cada grupo incluyó 5 cilindros contaminados y 1 no contaminado como control negativo. Tras la esterilización, el interior de los cilindros se cultivó durante 7 días. Resultados Se han obtenido un total de 1193 artículos en la búsqueda de los cuales 298 artículos cumplieron los criterios de inclusión, obteniéndose un total de 143 aplicaciones que se exponen a modo de fichas. En el estudio de esterilidad se observe crecimiento bacteriano de unas pocas unidades formadoras de colonias en 4 de los 5 controles positivos y en 2 de los 5 cilindros contaminados y esterilizados con Gas plasma. No se observó crecimiento en ninguno de los cilindros esteriliados con Óxido de etileno o Autoclave, ni tampoco en ninguno de los controles negativos. Sin embargo, aquellas muestras esterilizadas en Autoclave se encontraron completamente deformadas. Conclusiones Existen infinidad de aplicaciones de la impresión 3D hospitalaria en el campo de la cirugía ortopédica y traumatología. Las altas temperaturas alcanzadas durante el proceso de fabricación aditiva pueden disminuir la carga bacteriana de los biomodelos. Sin embargo, existe un riesgo potencial de contaminación durante el procedimiento, por lo que recomendamos la esterilización con Óxido de etileno para las impresiones intrahospitalarias de biomodelos y guías huecas realizadas con ácido poliláctico. En caso de utilizar Gas plasma, recomendamos un relleno del 100% o la utilización de otros materiales más resistentes a las altas temperaturas del Autoclave.Escuela de DoctoradoDoctorado en Investigación en Ciencias de la Salu

Radiation-free methods for navigated screw placement in slipped capital femoral epiphysis surgery

© 2019, CARS. Purpose: For orthopedic procedures, surgeons utilize intra-operative medical images such as fluoroscopy to plan screw placement and accurately position the guide wire with the intended trajectory. The number of fluoroscopic images needed depends on the complexity of the case and skill of the surgeon. Since more fluoroscopic images lead to more exposure and higher radiation dose for both surgeon and patient, a solution that decreases the number of fluoroscopic images would be an improvement in clinical care. Methods: This article describes and compares three different novel navigation methods and techniques for screw placement using an attachable Inertial Measurement Unit device or a robotic arm. These methods provide projection and visualization of the surgical tool trajectory during the slipped capital femoral epiphysis procedure. Results: These techniques resulted in faster and more efficient preoperative calibration and set up times compared to other intra-operative navigation systems in our phantom study. We conducted an experiment using 120 model bones to measure the accuracy of the methods. Conclusion: As conclusion, these approaches have the potential to improve accuracy of surgical tool navigation and decrease the number of required X-ray images without any change in the clinical workflow. The results also show 65% decrease in total error compared to the conventional manual approach