179 research outputs found
Optimisation des planifications chirurgicales de la scoliose idiopathique adolescente
Anatomie descriptive et fonctionnelle du rachis sain -- La scoliose idiopathique adolescente (SIA) -- Le traitement par instrumentation chirurgicale postĂ©rieure -- Ăvolution de l'instrumentation chirurgicale postĂ©rieure -- BiomĂ©canique du traitement par instrumentation chirurgicale postĂ©rieure -- Simulations numĂ©riques du traitement par instrumentation chirurgicale -- Revue des travaux antĂ©rieurs de notre Ă©quipe -- Sommaire de l'Ă©tat actuel des connaissances -- HypothĂšses, objectifs et cadre mĂ©thodologique -- Ătude de la variabilitĂ© des objectifs de correction du rachis scoliotique -- Scoliosis correction objectives in adolescent idiopathic scoliosis -- Optimisation des planifications chirurgicales de la scoliose -- Computer simulation for optimization of instrumentation strategies in adolescent idiopathic scoliosis -- Ătude prospective de l'optimisation de la chirurgie d'instrumentation sur un deuxiĂšme cas -- Effets de la variabilitĂ© des objectifs de correction sur des stratĂ©gies d'instrumentation du rachis scoliotique -- The repercussion of correction objectives on instrumentation strategies in adolescent idiopathic scoliosis
Computational modelling of the scoliotic spine: A literature review
open4siScoliosis is a deformity of the spine that in severe cases requires surgical treatment. There is still disagreement among clinicians as to what the aim of such treatment is as well as the optimal surgical technique. Numerical models can aid clinical decision-making by estimating the outcome of a given surgical intervention. This paper provided some background information on the modelling of the healthy spine and a review of the literature on scoliotic spine models, their validation, and their application. An overview of the methods and techniques used to construct scoliotic finite element and multibody models was given as well as the boundary conditions used in the simulations. The current limitations of the models were discussed as well as how such limitations are addressed in non-scoliotic spine models. Finally, future directions for the numerical modelling of scoliosis were addressed.Marco Viceconti and Giorgio Davico were supported by the EU funded project Mobilise-D. The charity Reuse-WithLove is gratefully acknowledged for the financial support to this research.openGould, Samuele L; Cristofolini, Luca; Davico, Giorgio; Viceconti, MarcoGould, Samuele L; Cristofolini, Luca; Davico, Giorgio; Viceconti, Marc
Computational modelling of the scoliotic spine: A literature review
Scoliosis is a deformity of the spine that in severe cases requires surgical treatment. There is still disagreement among clinicians as to what the aim of such treatment is as well as the optimal surgical technique. Numerical models can aid clinical decision-making by estimating the outcome of a given surgical intervention. This paper provided some background information on the modelling of the healthy spine and a review of the literature on scoliotic spine models, their validation, and their application. An overview of the methods and techniques used to construct scoliotic finite element and multibody models was given as well as the boundary conditions used in the simulations. The current limitations of the models were discussed as well as how such limitations are addressed in non-scoliotic spine models. Finally, future directions for the numerical modelling of scoliosis were addressed
A multi-criteria decision support for optimal instrumentation in scoliosis spine surgery
In adolescent idiopathic scoliosis, the selection of an optimal instrumentation configuration for correcting a specific spinal deformity is a challenging combinatorial problem. Current methods mostly rely on surgeons' expertise, which has been shown to lead to different treatment strategies for the same patients. In this work, a mathematical model of the human spine derived from in-vitro experimentally-obtained data was used to simulate the biomechanical behavior of the spine under the application of corrective forces and torques. The corrective forces and torques were optimized based on the particle swarm optimization algorithm for each combinatorially possible instrumentation strategy. Finally, a multi-criteria decision support for optimal instrumentation in scoliosis spine surgery has been proposed and applied to five patient data sets exhibiting similar spinal deformities according to two commonly used classification systems. Results indicated that the classification of the spinal deformities based on the current standardized clinical classifications systems is not a sufficient condition for recommending selective fusion of spinal motion segments. In addition, the particle swarm optimization algorithm was successfully applied to solve a realistic interdisciplinary clinical problem in a patient-specific fashion. The proposed method enables a better understanding of the biomechanical behavior of spinal structures and has the potential to become a standard tool in preoperative plannin
Preoperative assessment and evaluation of instrumentation strategies for the treatment of adolescent idiopathic scoliosis: computer simulation and optimization
UNLABELLED: BACKGROUND: A large variability in adolescent idiopathic scoliosis (AIS) correction objectives and instrumentation strategies was documented. The hypothesis was that different correction objectives will lead to different instrumentation strategies. The objective of this study was to develop a numerical model to optimize the instrumentation configurations under given correction objectives. METHODS: Eleven surgeons from the Spinal Deformity Study Group independently provided their respective correction objectives for the same patient. For each surgeon, 702 surgical configurations were simulated to search for the most favourable one for his particular objectives. The influence of correction objectives on the resulting surgical strategies was then evaluated. RESULTS: Fusion levels (mean 11.2, SD 2.1), rod shapes, and implant patterns were significantly influenced by correction objectives (p < 0.05). Different surgeon-specified correction objectives produced different instrumentation strategies for the same patient. CONCLUSIONS: Instrumentation configurations can be optimized with respect to a given set of correction objectives
Planning the Surgical Correction of Spinal Deformities: Toward the Identification of the Biomechanical Principles by Means of Numerical Simulation
The set of surgical devices and techniques to perform spine deformity correction has widened dramatically. Nevertheless, the rate of complications due to mechanical failure remains rather high. Indeed, basic research about the principles of deformity correction and the optimal surgical strategies (i.e. the choice of the fusion length, the most appropriate instrumentation, the degree of tolerable correction) did not progress as much as the techniques. In this work, a software approach for the biomechanical simulation of the correction of patient-specific spinal deformities aimed to the identification of its biomechanical principles is presented. The method is based on three dimensional reconstructions of the spinal anatomy obtained from biplanar radiographic images. A user-friendly graphical interface allows for the planning of the deformity correction and to simulate the instrumentation. Robust meshing of the instrumented spine is provided by using consolidated computational geometry and meshing libraries. Based on finite element simulation, the program predicts the loads acting in the instrumentation as well as in the biological tissues. A simple test case (reduction of a low grade spondylolisthesis at L3-L4) was simulated as a proof-of-concept. Despite the limitations of this approach, the preliminary outcome is promising and encourages a wide effort towards its refinement
Multimodal image fusion of anatomical structures for diagnosis, therapy planning and assistance
This paper provides an overview of work done in recent years by our research group to fuse multimodal images of the trunk of patients with Adolescent Idiopathic Scoliosis (AIS) treated at Sainte-Justine University Hospital Center (CHU). We first describe our surface acquisition system and introduce a set of clinical measurements (indices) based on the trunk's external shape, to quantify its degree of asymmetry. We then describe our 3D reconstruction system of the spine and rib cage from biplanar radiographs and present our methodology for multimodal fusion of MRI, X-ray and external surface images of the trunk We finally present a physical model of the human trunk including bone and soft tissue for the simulation of the surgical outcome on the external trunk shape in AIS.CIHR / IRS
The use of artificial intelligence algorithms to guide surgical treatment of adolescent idiopathic scoliosis
La scoliose idiopathique de lâadolescent (SIA) est une dĂ©formation tri-dimensionelle du rachis. Son traitement comprend lâobservation, lâutilisation de corsets pour limiter sa progression ou la chirurgie pour corriger la dĂ©formation squelettique et cesser sa progression. Le traitement chirurgical reste controversĂ© au niveau des indications, mais aussi de la chirurgie Ă entreprendre. MalgrĂ© la prĂ©sence de classifications pour guider le traitement de la SIA, une variabilitĂ© dans la stratĂ©gie opĂ©ratoire intra et inter-observateur a Ă©tĂ© dĂ©crite dans la littĂ©rature. Cette variabilitĂ© sâaccentue dâautant plus avec lâĂ©volution des techniques chirurgicales et de lâinstrumentation disponible.
Lâavancement de la technologie et son intĂ©gration dans le milieu mĂ©dical a menĂ© Ă lâutilisation dâalgorithmes dâintelligence artificielle informatiques pour aider la classification et lâĂ©valuation tridimensionnelle de la scoliose. Certains algorithmes ont dĂ©montrĂ© ĂȘtre efficace pour diminuer la variabilitĂ© dans la classification de la scoliose et pour guider le traitement.
Lâobjectif gĂ©nĂ©ral de cette thĂšse est de dĂ©velopper une application utilisant des outils dâintelligence artificielle pour intĂ©grer les donnĂ©es dâun nouveau patient et les Ă©vidences disponibles dans la littĂ©rature pour guider le traitement chirurgical de la SIA.
Pour cela une revue de la littĂ©rature sur les applications existantes dans lâĂ©valuation de la SIA fut entreprise pour rassembler les Ă©lĂ©ments qui permettraient la mise en place dâune application efficace et acceptĂ©e dans le milieu clinique. Cette revue de la littĂ©rature nous a permis de rĂ©aliser que lâexistence de âblack boxâ dans les applications dĂ©veloppĂ©es est une limitation pour lâintĂ©gration clinique ou la justification basĂ©e sur les Ă©vidence est essentielle.
Dans une premiĂšre Ă©tude nous avons dĂ©veloppĂ© un arbre dĂ©cisionnel de classification de la scoliose idiopathique basĂ© sur la classification de Lenke qui est la plus communĂ©ment utilisĂ©e de nos jours mais a Ă©tĂ© critiquĂ©e pour sa complexitĂ© et la variabilitĂ© inter et intra-observateur. Cet arbre dĂ©cisionnel a dĂ©montrĂ© quâil permet dâaugmenter la prĂ©cision de classification proportionnellement au temps passĂ© Ă classifier et ce indĂ©pendamment du niveau de connaissance sur la SIA.
Dans une deuxiĂšme Ă©tude, un algorithme de stratĂ©gies chirurgicales basĂ© sur des rĂšgles extraites de la littĂ©rature a Ă©tĂ© dĂ©veloppĂ© pour guider les chirurgiens dans la sĂ©lection de lâapproche et les niveaux de fusion pour la SIA. Lorsque cet algorithme est appliquĂ© Ă une large base de donnĂ©e de 1556 cas de SIA, il est capable de proposer une stratĂ©gie opĂ©ratoire similaire Ă celle dâun chirurgien expert dans prĂȘt de 70% des cas. Cette Ă©tude a confirmĂ© la possibilitĂ© dâextraire des stratĂ©gies opĂ©ratoires valides Ă lâaide dâun arbre dĂ©cisionnel utilisant des rĂšgles extraites de la littĂ©rature.
Dans une troisiĂšme Ă©tude, la classification de 1776 patients avec la SIA Ă lâaide dâune carte de Kohonen, un type de rĂ©seaux de neurone a permis de dĂ©montrer quâil existe des scoliose typiques (scoliose Ă courbes uniques ou double thoracique) pour lesquelles la variabilitĂ© dans le traitement chirurgical varie peu des recommandations par la classification de Lenke tandis que les scolioses a courbes multiples ou tangentielles Ă deux groupes de courbes typiques Ă©taient celles avec le plus de variation dans la stratĂ©gie opĂ©ratoire.
Finalement, une plateforme logicielle a Ă©tĂ© dĂ©veloppĂ©e intĂ©grant chacune des Ă©tudes ci-dessus. Cette interface logicielle permet lâentrĂ©e de donnĂ©es radiologiques pour un patient scoliotique, classifie la SIA Ă lâaide de lâarbre dĂ©cisionnel de classification et suggĂšre une approche chirurgicale basĂ©e sur lâarbre dĂ©cisionnel de stratĂ©gies opĂ©ratoires. Une analyse de la correction post-opĂ©ratoire obtenue dĂ©montre une tendance, bien que non-statistiquement significative, Ă une meilleure balance chez les patients opĂ©rĂ©s suivant la stratĂ©gie recommandĂ©e par la plateforme logicielle que ceux aillant un traitement diffĂ©rent.
Les Ă©tudes exposĂ©es dans cette thĂšse soulignent que lâutilisation dâalgorithmes dâintelligence artificielle dans la classification et lâĂ©laboration de stratĂ©gies opĂ©ratoires de la SIA peuvent ĂȘtre intĂ©grĂ©es dans une plateforme logicielle et pourraient assister les chirurgiens dans leur planification prĂ©opĂ©ratoire.Adolescent idiopathic scoliosis (AIS) is a three-dimensional deformity of the spine. Management of AIS includes conservative treatment with observation, the use of braces to limit its progression or surgery to correct the deformity and cease its progression. Surgical treatment of AIS remains controversial with respect to not only indications but also surgical strategy. Despite the existence of classifications to guide AIS treatment, intra- and inter-observer variability in surgical strategy has been described in the literature.
Technological advances and their integration into the medical field have led to the use of artificial intelligence (AI) algorithms to assist with AIS classification and three-dimensional evaluation. With the evolution of surgical techniques and instrumentation, it is probable that the intra- and inter-observer variability could increase. However, some AI algorithms have shown the potential to lower variability in classification and guide treatment.
The overall objective of this thesis was to develop software using AI tools that has the capacity to integrate AIS patient data and available evidence from the literature to guide AIS surgical treatment.
To do so, a literature review on existing computer applications developed with regards to AIS evaluation and management was undertaken to gather all the elements that would lead to usable software in the clinical setting. This review highlighted the fact that many applications use a non-descript âblack boxâ between input and output, which limits clinical integration where management based on evidence is essential.
In the first study, we developed a decision tree to classify AIS based on the Lenke scheme. The Lenke scheme was popular in the past, but has recently been criticized for its complexity leading to intra and inter-observer variability. The resultant decision tree demonstrated an ability to increase classification accuracy in proportion to the time spent classifying. Importantly, this increase in accuracy was independently of previous knowledge about AIS.
In the second study, a surgical strategy rule-based algorithm was developed using rules extracted from the literature to guide surgeons in the selection of the approach and levels of fusion for AIS. When this rule-based algorithm was tested against a database of 1,556 AIS cases, it was able to output a surgical strategy similar to the one undertaken by an expert surgeon in 70% of cases. This study confirmed the ability of a rule-based algorithm based on the literature to output valid surgical strategies.
In the third study, classification of 1,776 AIS patients was undertaken using Kohonen Self-Organizing-Maps (SOM), which is a kind of neural network that demonstrates there are typical AIS curve types (i.e: single curves and double thoracic curves) for which there is little variability in surgical treatment when compared to the recommendations from the Lenke scheme. Other curve types (i.e: multiple curves or in transition zones between typical curves) have much greater variability in surgical strategy.
Finally, a software platform integrating all the above studies was developed. The interface of this software platform allows for: 1) the input of AIS patient radiographic measurements; 2) classification of the curve type using the decision tree; 3) output of surgical strategy options based on rules extracted from the literature. A comparison of surgical correction obtained by patients receiving surgical treatment suggested by the software showed a tendency to obtain better balance -though non-statistically significant - than those who were treated differently from the surgical strategies outputted by the software.
Overall, studies from this thesis suggest that the use of AI algorithms in the classification and selection of surgical strategies for AIS can be integrated in a software platform that could assist the surgeon in the planning of appropriate surgical treatment
The International Research Society of Spinal Deformities (IRSSD) and its contribution to science
From the time of its initial, informal meetings starting in 1980 to its formal creation in 1990, the IRSSD has met on a bi-annual basis to discuss all aspects of the spine and associated deformities. It has encouraged open discussion on all topics and, in particular, has tried to be the seed-bed for new ideas. The members are spread around the world and include people from all areas of academia as well as the most important people, the patients themselves. Most notably, application of the ideas and results of the research has always been at the forefront of the discussions. This paper was conceived with the idea of evaluating the impact made by the IRSSD over the last 30 years in the various areas and is intended to create discussion for the upcoming meeting in Montreal regarding future focus: "We are lost over the Atlantic Ocean but we are making good time.
Correction objectives have higher impact than screw pattern and density on the optimal 3D correction of thoracic AIS: a biomechanical study
Study design
Assessment of screw pattern, implant density (ID), and optimization of 3D correction through computer-based biomechanical models.
Objective
To investigate how screw pattern and ID affect intraoperative 3D correction of thoracic curves in adolescent idiopathic scoliosis, and how different correction objectives impact the optimal screw pattern.
Summary of background data
Screw pattern, ID, correction objectives and surgical strategies for posterior fusion of AIS are highly variable among experienced surgeons. The âoptimalâ instrumentation remains not well defined.
Methods
10 patient-specific multibody models of representative adolescent idiopathic scoliosis Lenke 1A cases were built and used to compare alternative virtual correction surgeries. Five screw patterns and IDs (average: 1.6 screws/instrumented level, range: 1.2â2) were simulated, considering concave rod rotation, en bloc derotation, and compression/distraction as primary correction maneuvers. 3D correction descriptors were quantified in the coronal, sagittal and transverse planes. An objective function weighting the contribution of intraoperative 3D correction and mobility allowed rating of the outcomes of the virtual surgeries. Based on surgeon-dependent correction objectives, the optimal result among the simulated constructs was identified.
Results
Low-density (IDââ€â1.4) constructs provided equivalent 3D correction compared to higher (IDââ„â1.8) densities (average differences ranging between 2° and 3°). The optimal screw pattern varied from case to case, falling within the low-density screw category in 14% of considered scenarios, 73% in the mid-density (1.4â<âIDâ<â1.8) and 13% in the high-density. The optimal screw pattern was unique in five cases; multiple optima were found in other cases depending on the considered correction objectives.
Conclusions
Low-density screw patterns provided equivalent intraoperative 3D correction to higher-density patterns. Simulated surgeonâs choice of correction objectives had the greatest impact on the selection of the optimal construct for 3D correction, while screw density and ID had a limited impact
- âŠ