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INTRODUCTION: Different factors can lead to inconsistencies in measurement for the acetabular version using 2D axial CT-cuts. We have defined a "true" anteversion angle (AV angle) in the physiological position of the pelvis in 3D with the largest European population measured to our knowledge. MATERIAL AND METHODS: We analyzed 258 hemipelvises and created 3D models. We compared the results of our AV angle 3D method with the cross-sectional cuts of the same acetabula. We included factors like side, sex, body mass index, and patient positioning. RESULTS: Overall, the mean (SD) AV angle was 16.1 (5.9)° as measured with the 3D method and 22.0 (6.0)° as measured with the 2D method (p < 0.0001). Measured with both the 3D and the 2D method, the AV angle was significantly larger in female than in male individuals (p < 0.0001). In the 2D method, the AV angle estimation was influenced by the pelvic tilt. CONCLUSION: We propose a more accurate method for the measurement of the AV angle of the acetabulum in a 3D model that is not influenced by patient positioning or pelvic tilt. We provide a computational model that will facilitate operative decisions and improve preoperative planning. We confirm that 3D measurement should be the gold standard in measuring the acetabular anteversion.
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Acetábulo , Tomografía Computarizada por Rayos X , Masculino , Femenino , Humanos , Acetábulo/diagnóstico por imagen , Acetábulo/cirugía , Estudios Transversales , Tomografía Computarizada por Rayos X/métodos , Pelvis , Posicionamiento del PacienteRESUMEN
The free fibula osteoseptocutaneous flap is the standard for reconstruction of extensive mandibular defects. The procedure must be precise to achieve the required functional and aesthetic results. The aim of the present study was to calculate retrospectively the exact differences in surgical outcome based on preoperative and postoperative Computed Tomography data sets. Ten patients with unilateral reconstructions of the mandible with a fibula based on conventional planning were analyzed quantitatively, applying mirroring techniques with direct comparison of the theoretically optimum with the actual reconstruction. The results showed that there is a significant discrepancy between what is actually achieved and the theoretical optimum. The result of the present retrospective analysis shows that there is room for further improvement of the outcome in complex mandible reconstruction cases.
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Trasplante Óseo/métodos , Carcinoma de Células Escamosas/cirugía , Peroné/trasplante , Mandíbula/cirugía , Neoplasias Mandibulares/cirugía , Cirugía Asistida por Computador , Adulto , Femenino , Humanos , Masculino , Persona de Mediana Edad , Procedimientos de Cirugía Plástica , Estudios Retrospectivos , Colgajos Quirúrgicos/irrigación sanguínea , Tomografía Computarizada por Rayos XRESUMEN
Tumors in the pelvic region cause deformation and destruction of bony structures. Because the original pelvic anatomy cannot be adequately assessed at the tumor site, reconstruction with patient-specific implants is required. A widely used strategy for the reconstructive planning is mirroring of the contralateral side. We analyzed the statistical shape model (SSM)-based reconstruction method and compared it with the mirroring approach. Our approach used a gender-specific pelvic SSM (n = 50 for each gender) to generate implant geometries. The main objectives of this study were to analyze and evaluate the virtual anatomical reconstruction of eight tumor-damaged pelvic bones using the SSM approach. We achieved an overall mean deviation distance of 0.89 mm and 1.26 mm for the reconstruction of the equivalent defect in the healthy hemipelvis. Quantitative comparison with the mirroring method showed that the SSM-based reconstruction method reconstructs the defect with the same clinically acceptable accuracy as the mirroring method. The study demonstrates that the presented model can be a valuable tool for the planning of pelvic reconstructive surgery and implant design.
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Quistes Óseos Aneurismáticos/patología , Neoplasias Óseas/patología , Procesamiento de Imagen Asistido por Computador , Modelos Estadísticos , Huesos Pélvicos/patología , Factores Sexuales , Adolescente , Adulto , Quistes Óseos Aneurismáticos/diagnóstico por imagen , Quistes Óseos Aneurismáticos/cirugía , Neoplasias Óseas/diagnóstico por imagen , Neoplasias Óseas/cirugía , Condrosarcoma/diagnóstico por imagen , Condrosarcoma/patología , Condrosarcoma/cirugía , Femenino , Humanos , Masculino , Persona de Mediana Edad , Modelos Anatómicos , Osteosarcoma/diagnóstico por imagen , Osteosarcoma/patología , Osteosarcoma/cirugía , Huesos Pélvicos/diagnóstico por imagen , Huesos Pélvicos/cirugía , Plasmacitoma/diagnóstico por imagen , Plasmacitoma/patología , Plasmacitoma/cirugía , Tomografía Computarizada por Rayos X , Adulto JovenRESUMEN
BACKGROUND: Dynamic three-dimensional (3D) deformation of the pelvic bones is a crucial factor in the successful design and longevity of complex orthopaedic oncological implants. The current solutions are often not very promising for the patient; thus it would be interesting to measure the dynamic 3D-deformation of the whole pelvic bone in order to get a more realistic dataset for a better implant design. Therefore we hypothesis if it would be possible to combine a material testing machine with a 3D video motion capturing system, used in clinical gait analysis, to measure the sub millimetre deformation of a whole pelvis specimen. METHOD: A pelvis specimen was placed in a standing position on a material testing machine. Passive reflective markers, traceable by the 3D video motion capturing system, were fixed to the bony surface of the pelvis specimen. While applying a dynamic sinusoidal load the 3D-movement of the markers was recorded by the cameras and afterwards the 3D-deformation of the pelvis specimen was computed. The accuracy of the 3D-movement of the markers was verified with 3D-displacement curve with a step function using a manual driven 3D micro-motion-stage. RESULTS: The resulting accuracy of the measurement system depended on the number of cameras tracking a marker. The noise level for a marker seen by two cameras was during the stationary phase of the calibration procedure ± 0.036 mm, and ± 0.022 mm if tracked by 6 cameras. The detectable 3D-movement performed by the 3D-micro-motion-stage was smaller than the noise level of the 3D-video motion capturing system. Therefore the limiting factor of the setup was the noise level, which resulted in a measurement accuracy for the dynamic test setup of ± 0.036 mm. CONCLUSION: This 3D test setup opens new possibilities in dynamic testing of wide range materials, like anatomical specimens, biomaterials, and its combinations. The resulting 3D-deformation dataset can be used for a better estimation of material characteristics of the underlying structures. This is an important factor in a reliable biomechanical modelling and simulation as well as in a successful design of complex implants.
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Huesos/fisiopatología , Imagenología Tridimensional/instrumentación , Imagenología Tridimensional/métodos , Pelvis/fisiopatología , Grabación en Video/instrumentación , Fenómenos Biomecánicos , Calibración , Humanos , Modelos Biológicos , Movimiento (Física) , Grabación en Video/métodosAsunto(s)
Trasplante Óseo/métodos , Ilion/cirugía , Mandíbula/cirugía , Procedimientos de Cirugía Plástica/métodos , Cirugía Asistida por Computador/métodos , Recolección de Tejidos y Órganos/métodos , Trasplante Autólogo , Algoritmos , Puntos Anatómicos de Referencia/anatomía & histología , Angiografía/métodos , Simulación por Computador , Diseño Asistido por Computadora , Implantación Dental Endoósea , Estudios de Seguimiento , Humanos , Ilion/anatomía & histología , Imagenología Tridimensional/métodos , Modelos Anatómicos , Planificación de Atención al Paciente , Programas Informáticos , Tomografía Computarizada por Rayos X/métodos , Sitio Donante de Trasplante/anatomía & histología , Sitio Donante de Trasplante/cirugía , Resultado del Tratamiento , Interfaz Usuario-ComputadorRESUMEN
Craniometaphyseal dysplasia is an extremely rare, genetic bone-remodeling disorder. Comparable to osteopetrosis, fibrous dysplasia, and other infrequent conditions, craniometaphyseal dysplasia is characterized by progressive diffuse hyperostosis of the neuro- and viscerocranium. Affected patients present with a pathognomonic dysmorphia: macrocephalus, hypertelorism, bulky facial skeleton, and a prominent mandible. Progressive thickening and petrification of the craniofacial bones can continue throughout life, often resulting in neurological symptoms due to obstruction of the cranial nerves in the foramina and therefore immediately requiring neurosurgical interventions to avoid persistent symptoms with severe impairment of function. Treatment is largely infeasible given the lack of suitable tools to perform a craniotomy through the gross calvarial bone. In this paper, the authors present a complete process chain from the CT-based generation of an individual patient's model displaying his pathology to optimized preoperative planning of the skull's shape with a thickness of about 6-7 mm. For concise verification of the surgical plan in an operating room environment, a 3D real-time navigation prototype system was utilized. To guarantee realization of the surgery in a reasonable time frame, the mechanical tools were preoperatively selected for optimizing the ablation rate in porcine and bovine bone, which were comparable to that in the patient. This process chain was developed in a modular way, so that it could be easily adopted completely or partially for other surgical indications. A 21-year-old man was treated according to this sophisticated concept. Skull bone more than 50 mm thick in some regions was reduced to physiological thickness. The patient was thus in a stage that neurosurgical interventions could be performed with a regular risk within a reasonable time of treatment.