Radiological Society of North America (RSNA) 3D printing Special Interest Group (SIG): Guidelines for medical 3D printing and appropriateness for clinical scenarios

Este número da revista Cadernos de Estudos Sociais estava em organização quando fomos colhidos pela morte do sociólogo Ernesto Laclau. Seu falecimento em 13 de abril de 2014 surpreendeu a todos, e particularmente ao editor Joanildo Burity, que foi seu orientando de doutorado na University of Essex, Inglaterra, e que recentemente o trouxe à Fundação Joaquim Nabuco para uma palestra, permitindo que muitos pudessem dialogar com um dos grandes intelectuais latinoamericanos contemporâneos. Assim, buscamos fazer uma homenagem ao sociólogo argentino publicando uma entrevista inédita concedida durante a sua passagem pelo Recife, em 2013, encerrando essa revista com uma sessão especial sobre a sua trajetória

3D-printing techniques in a medical setting : a systematic literature review

Background: Three-dimensional (3D) printing has numerous applications and has gained much interest in the medical world. The constantly improving quality of 3D-printing applications has contributed to their increased use on patients. This paper summarizes the literature on surgical 3D-printing applications used on patients, with a focus on reported clinical and economic outcomes. Methods: Three major literature databases were screened for case series (more than three cases described in the same study) and trials of surgical applications of 3D printing in humans. Results: 227 surgical papers were analyzed and summarized using an evidence table. The papers described the use of 3D printing for surgical guides, anatomical models, and custom implants. 3D printing is used in multiple surgical domains, such as orthopedics, maxillofacial surgery, cranial surgery, and spinal surgery. In general, the advantages of 3D-printed parts are said to include reduced surgical time, improved medical outcome, and decreased radiation exposure. The costs of printing and additional scans generally increase the overall cost of the procedure. Conclusion: 3D printing is well integrated in surgical practice and research. Applications vary from anatomical models mainly intended for surgical planning to surgical guides and implants. Our research suggests that there are several advantages to 3D- printed applications, but that further research is needed to determine whether the increased intervention costs can be balanced with the observable advantages of this new technology. There is a need for a formal cost-effectiveness analysis

Development of a Personalised 3D Mandibular Distraction Device for the Management of Craniofacial Microsomia

Introduction: Surgical correction of the facial skeleton in deformity has evolved significantly over the recent past as techniques and technology have improved. Where there exist significant skeletal discrepancies, large skeletal changes are required and there remains a need to further improve upon our current standard to achieve these surgical goals. Distraction osteogenesis (DO) is a technique that induces bone formation without the need for bone grafting and allows for guided shape change in addition to expanding the overlying tissue envelope. Current mandibular distractors are limited as they are bulky; there are wound problems related to the external siting of the actuator; there is a limited geometry of possible distraction; the final result is unpredictable; they function in a discontinuous rather than continuous motion and they require daily winding by the patient. There exists a clear potential benefit to patients should these drawbacks be overcome. Aim: The aim of the project is to design a novel device to modify the shape of the deformed jaw to a prescribed, predetermined shape that is specific to the patient and that does not require external manipulation. Methods: The mechanical properties of helical springs constructed from a nonlinear material were tested to review their suitability for use as actuators to deliver force in a fully buried continuous distractor. A finite element model was then created to generalise the concept for use where different forces may be required. Lastly a prototype was designed and empirically tested ex-vivo to assess whether the aims of the project were fulfilled. Results: The nonlinear material was found to deliver adequate, continuous and relatively constant force over a distance in keeping with DO. The finite element model was demonstrated to accurately represent the empirical properties of the helical spring. The prototype designed was able to modify the shape of a deformed jaw to a predetermined position without requiring external manipulation in a surgical model. Discussion: This project develops and tests a prototype that is fully buried and can achieve multiplanar continuous DO without the need for patient involvement and therefore provides novel technology as a solution to improving practice

Orthodontic Approach to Hemifacial Microsomia

Aim and objective: To present a growing patient with unilateral mandibular hypoplasia and microtia involved in the first and second branchial arch syndrome (FSBAS) treated with functional appliance. Background: The FSBAS comprises several developmental facial hypoplasia in ear and maxillofacial bones, resulting in hemifacial microsomia. Treatment for hemifacial microsomia varies greatly depending on the grade of mandibular deformities. Functional appliance treatment during growth period is available for mild to moderate mandibular deformities. However, there are few reports of hemifacial microsomia treated with functional appliance. Case description: The patient, an 8-year-and-5-month-old girl, had a chief complaint of mandibular deviation. She had been diagnosed with the FSBAS at birth. Her facial profile was straight and panoramic radiograph indicated that the mandibular ramal height of the affected side was about 60.4% compared to the unaffected side. The occlusal cant was 6°, and the right maxilla and mandible showed severe growth deficiency. At the age of 10 years, functional appliance with expander was used; for 2 years 6 months, the maxillomandibular growth was controlled and from panoramic radiograph, the ramus height of the affected side was increased to 65.0% compared to the unaffected left mandibular ramus. At the age of 12 years and 8 months, multibracket treatment was initiated. After 32 months of active treatment, proper occlusion with functional Class I canine and molar relationships was obtained, although facial asymmetry associated with the difference of ramus heights still existed. The resulting occlusion was stable during 1.5-year retention period. Conclusion: Our results indicated the importance of orthopedic treatment during growth period in the patient with hemifacial macrosomia involving the FSBAS. Clinical significance: This report proposes an efficacy of conventional orthodontic treatment for growing patients with hemifacial macrosomia involved in the FSBAS

Precise screw positioning at the mandibular angle: computer assisted versus template coded

BACKGROUND: Buried intraoral devices for distraction osteogenesis in mandibular deformities have numerous advantages, but success depends on the precise positioning of these devices. Although most centers nowadays use template-guided techniques for precise positioning, computer navigation has been described as a promising technique. Surgical navigation during device placement could become a viable method because it affords certainty in defining a device position. METHODS: A clinical situation was simulated by means of mounting a mandible model inside a phantom head. Screws were positioned according to a preoperative plan through transoral and transbuccal approaches, with both template-coded and freehand computer navigation. RESULTS: With template-coded navigation, the medium deviation from the planned position was 0.63 mm (range, 0.00-1.24 mm). With commercial freehand surgical computer navigation, the medium deviation was significantly higher at 0.98 mm (range, 0.00-3.13 mm). CONCLUSIONS: Computer-assisted surgery can provide a high level of accuracy in the region of the mandibular angle where precision is crucial for buried intraoral distraction devices. However, template-coded guidance does provide a significantly higher level of accuracy and therefore represents the gold standard

Volumetric velopharyngeal space modifications in patients with and without cleft palate undergoing Le Fort 1 maxillary advancement

Historique & Objectifs: Les effets de l’avancement maxillaire (AM) sur l’anatomie velopharyngée ont déjà été étudiés en utilisant la céphalométrie. Cette modalité ne permet toutefois pas de bien caractériser les tissus mous. Le but de cette étude est de comparer la configuration de l’espace vélopharyngé en pré- et post-opératoire, telle que mesurée par tomodensitométrie (TDM). De plus, notre objectif est d’analyser et de comparer les différences dans ces mesures chez les patients avec et sans fente palatine (FP). Méthodologie: Ceci est une étude rétrospective portant sur 44 patients avec et sans FP, traités avec AM pour une hypoplasie maxillaire et une malocclusion dento-squelettique. Les TDM pré- et post-opératoires ont été comparés en se basant sur des repères préétablis. Des distances linéaires, des aires de sections transversales et des mesures volumétriques ont été mesurées en utilisant des reconstructions tridimensionnelles des TDM. Résultats: Pour les distances linéaires mesurées, une différence statistiquement significative a été notée pour les mesures linéaires du nasopharynx et du palais mou (25.1 vs 28.5 mm p=0.001 et 6.5 vs 7.6 mm p=0.026, respectivement). Les aires des sections transversales au niveau du nasopharynx et du palais mou ainsi que l'évaluation volumétrique de l'espace vélopharyngé n'ont pas démontrées une différence statistiquement significative en comparant les mesures en pré- et post-opératoire (p>0,05). En comparant les patients avec et sans FP, une différence statistiquement significative n’a été notée que pour la distance linéaire et l’aire de la section transversale du nasopharynx (p=0.045 et p=0.04, respectivement). Un antécédent de réparation de FP n’était pas prédictif de différences de mesures pré- et post-opératoire. Conclusion: Nos résultats confirment que, bien que certaines modifications structurelles de l’espace vélopharyngé soient inhérentes à l’AM chez les patients avec FP, leurs aires et volumes ne semblent pas changer de façon significative. Ces changements sont indépendants d’une histoire de FP réparée.Background & Purpose: The effects of maxillary advancement (MA) on velopharyngeal anatomy have primarily been studied using lateral cephalometric radiographs. However, with recent advances in orthognathic surgery, there is an increased need for more detailed and precise imaging such as computerized tomographic (CT) scan reconstructions, to help in surgical planning and to measure outcomes. The purpose of this study is to compare the pre-and post-operative velopharyngeal space configuration modifications as measured on CT scans. The aim is also to assess differences in these airway measures between patients with and without history of prior repaired cleft palate (CP). Methods: This is a retrospective cohort study of 44 patients with and without CP who were treated with MA for midface hypoplasia and secondary malocclusion at skeletal maturity. The pre-and post-operative CT scans were compared with respect to pre-established landmarks. Linear distances, cross-sectional areas, and volumes were measured using 3-dimensional (3D) CT scan reconstructions. Results: For the linear distances measured, a statistically significant difference was found when comparing the pre-and post-operative measures of the narrowest part of the nasopharynx and the narrowest part of the retropalatal airway space (25.1 vs 28.5 mm p=0.001 and 6.5 vs 7.6 mm p=0.026, respectively). Retropalatal cross-sectional areas, nasopharyngeal cross-sectional areas and the volumetric assessment of the nasopharyngeal space showed no statistically significant differences when comparing pre-and post-operative scans (p>0.05). The main effect of palatal repair (CP vs. Non-CP) showed that there was only a statistically significant difference for the measures of the narrowest part of the nasopharynx and the nasopharyngeal cross-sectional area (p=0.045 and p=0.04, respectively). Mean changes in the measures did not differ over time (pre-and post-op) depending on whether there was prior history of CP repair. Conclusion: Our results support the hypothesis that although structural modifications of the pharyngeal space are inherent to MA in patients with CP, its surface area and volume do not change significantly. These changes are also independent of history of previous CP repair

Radiological Society of North America (RSNA) 3D printing Special Interest Group (SIG): guidelines for medical 3D printing and appropriateness for clinical scenarios

Abstract Medical three-dimensional (3D) printing has expanded dramatically over the past three decades with growth in both facility adoption and the variety of medical applications. Consideration for each step required to create accurate 3D printed models from medical imaging data impacts patient care and management. In this paper, a writing group representing the Radiological Society of North America Special Interest Group on 3D Printing (SIG) provides recommendations that have been vetted and voted on by the SIG active membership. This body of work includes appropriate clinical use of anatomic models 3D printed for diagnostic use in the care of patients with specific medical conditions. The recommendations provide guidance for approaches and tools in medical 3D printing, from image acquisition, segmentation of the desired anatomy intended for 3D printing, creation of a 3D-printable model, and post-processing of 3D printed anatomic models for patient care.https://deepblue.lib.umich.edu/bitstream/2027.42/146524/1/41205_2018_Article_30.pd