242 research outputs found
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
Quantitative pathophysiology in rabbit models of early onset scoliosis and expansion thoracoplasty
Thesis (Ph.D.)--Boston UniversityEarly onset deformity of the spine and chest wall (initiated <8 years of age) is associated with declining respiratory function and increased morbidity at adulthood relative to adolescent onset deformity of comparable severity. In young children it is presumed that inhibition of thoracic growth during late stage alveolarization leads to an irreversible loss of pulmonary growth and thoracic function. Consequently there is clinical incentive to treat children with growth-preserving therapies as early as possible. In particular thoracic reconstruction surgeries have gained clinical acceptance over the last 15 years with encouraging results, however due to the delicate nature of these patients and the absence of a proper untreated control population there is limited prospective evidence to objectively evaluate the benefits of these surgeries on respiratory health. Additionally, controversy remains with regard to the proper timing of surgical intervention and if greater gains in growth and function are achieved with treatment at an earlier age.
Thus the primary aims of this current study were 1) to develop a surgical rabbit model representing early onset thoracic deformity (onset at 3 weeks postnatal) from which to characterize the natural progression of thoracic deformity in association with pulmonary growth and function, and 2) to use deformity rabbits from aim 1 to evaluate effectiveness of thoracic reconstruction, via expansion thoracoplasty, to preserve thoracic growth, pulmonary growth, and respiratory function with particular consideration regarding post-natal timing of intervention by evaluating separate early (7 weeks of age) and late (11 weeks of age) treatment cohorts. All rabbits were evaluated longitudinally until skeletal maturity (28 weeks of age) via pulmonary function testing and computed tomography (CT) imaging. Secondary aims were 3) to characterize the functional and structural respiratory heterogeneity occurring in these rabbits through evaluation of regional specific volume distributions via CT deformable-image-registration and through estimation of dynamic heterogeneity via inverse modeling of the respiratory input impedance, and 4) to evaluate the response of biological mechanisms in the alveolar microstructure in these rabbits through postmortem immunohistochemical assays for growth factors associated with angiogenesis (VEGF pathway) and cell proliferation (Ki-67 antibody).
Our findings highlight the nature of pulmonary hypoplasia under restrictive conditions; the extent of respiratory growth and function at maturity was highly predictable from thoracic geometry measured at 6 weeks in untreated deformity rabbits. From this predictive knowledge gains in growth and function associated with expansion thoracoplasty are determined, our evidence suggests that treatment benefits to lung growth are largely offset by detrimental effects of surgery and early surgery could only provide improvements in severe cases where expected outcomes are very poor, benefits to late treatment rabbits were inconclusive. A forward-inverse modeling approach to link empirical data on specific volume and respiratory impedance shows that inherent structural heterogeneity limits the sensitive detection of heterogeneity originating from a disease process. Lastly post-mortem evidence of increased cellular proliferation is shown in the pulmonary parenchyma of thoracoplasty treated rabbits
Advances on Scoliogeny, Diagnosis and Management of Scoliosis and Spinal Disorders
This book contains research articles on the advances in the aetiology of idiopathic scoliosis (IS), the spinal growth related to the implementation of growth modulation for the surgical treatment of early-onset IS, the non-surgical treatment of IS using Physiotheraputic Scoliosis Specific Exercises, and braces. Additionally, it focuses on issues related to surgical treatment, issues related to body posture and the quality of life of this sensitive group of people. The high quality of published papers in this Special Issue of the JCM serve these objectives
A review of the effectiveness of lower limb orthoses used in cerebral palsy
To produce this review, a systematic literature search was conducted for relevant articles published in the period between the date of the previous ISPO consensus conference report on cerebral palsy (1994) and April 2008. The search terms were 'cerebral and pals* (palsy, palsies), 'hemiplegia', 'diplegia', 'orthos*' (orthoses, orthosis) orthot* (orthotic, orthotics), brace or AFO
Biomechanical Modeling of Vertebral Mechanobiological Growth and of the Deformation Process in Adolescent Idiopathic Scoliosis
RĂSUMĂ
La scoliose idiopathique chez lâadolescent est une dĂ©formation tridimensionnelle du rachis se dĂ©veloppant durant la croissance. Plusieurs Ă©tudes rapportent que la progression de la dĂ©formation scoliotique est influencĂ©e par des facteurs biomĂ©caniques. La dĂ©formation scoliotique, lâasymĂ©trie de la balance du rachis et lâactivitĂ© musculaire sont responsables du chargement asymĂ©trique sur les plaques de croissances. Ces facteurs modifient la rĂ©partition entre le cĂŽtĂ© concave-convexe du taux de croissance et, par consĂ©quent, conduit Ă un cercle vicieux de progression de la dĂ©formation scoliotique. Le processus biomĂ©canique de la progression de la scoliose a Ă©tĂ© Ă©tudiĂ© dans la littĂ©rature en considĂ©rant principalement une composante de chargement axiale pour la reprĂ©sentation de la croissance.
Lâobjectif gĂ©nĂ©ral de ce projet est dâĂ©tudier la biomĂ©canique multiaxiale de la progression scoliotique. Le but spĂ©cifique du projet est de vĂ©rifier que le processus de dĂ©formation, impliquant la croissance et sa modulation mĂ©canobiologique par des charges multi-axiales, est stimulable numĂ©riquement par la mĂ©thode des Ă©lĂ©ments finis, et que ces charges multi-axiales exercĂ©es sur les plaques de croissance Ă©piphysaires sont responsables des dĂ©formations caractĂ©ristiques des vertĂšbres et rachis scoliotiques. Le chargement utilisĂ© pour simuler la pathologie consiste en des forces primaires axiales asymĂ©triques combinĂ©es Ă des forces secondaires de cisaillement et de torsion. Afin dâatteindre ce but, le projet a Ă©tĂ© divisĂ© en trois parties. La premiĂšre partie a consistĂ© Ă faire une Ă©tude comparative de deux techniques de modĂ©lisation afin de simuler les concepts de croissance mĂ©canobiologique. La seconde partie a consistĂ© Ă dĂ©velopper un nouveau modĂšle de croissance mĂ©canobiologique, basĂ© sur lâĂ©nergie de stimulation, afin de reprĂ©senter les dĂ©formations vertĂ©brales rĂ©sultant du chargement multiaxial. La troisiĂšme partie a consistĂ© Ă soumettre le nouveau modĂšle numĂ©rique Ă diffĂ©rents cas de chargements et Ă analyser leurs influences sur la croissance et sur la progression de la scoliose.
Dans la premiĂšre partie, les formulations analytiques de la croissance mĂ©canobiologique dĂ©veloppĂ©es par Stokes et coll. (1990) et Carter et coll. (1988) ont Ă©tĂ© comparĂ©es entre elles Ă lâaide dâun modĂšle par Ă©lĂ©ments finis dâune vertĂšbre thoracique. La vertĂšbre et la plaque de croissance adjacente supĂ©rieure ont Ă©tĂ© modĂ©lisĂ©es par des Ă©lĂ©ments solides 3D linĂ©aires.----------ABSTRACT
Adolescent idiopathic scoliosis is a three dimensional deformity of spine that mostly occurs during the growth spurt. It is generally accepted that the progression of scoliotic deformities is influenced by biomechanical factors. Asymmetrical loading of vertebral growth plates resulting from an initial scoliotic curve or asymmetric balance or muscle recruitment are modifying the concave-convex side growth rate, thus leading to a vicious circle of scoliosis progression. The mechanobiological process of scoliosis was previously investigated, but mainly considering the axial loading component for growth.
The general objective of this project was to study the multi-axial biomechanics of scoliosis progression. The specific objective was to model the deformation process, including the spinal growth and mechanobiological growth modulation due to multi-axial loads, and analyze how these loads are involved in the resulting characteristic scoliotic deformities. This tested pathomechanism presents the primary loading characteristics of asymmetric axial forces combined with secondary shear and torsion. In order to address the proposed research objectives, this project was divided into three parts. The first one was a comparative study and analysis of two modeling techniques to simulate existing concepts of mechanobiological growth. The second part was the development of a novel model of mechanobiological growth based on energy stimulus that enabled to represent the vertebral changes due to multi-axial loading. In the last part, this model was exploited to simulate the effect of different loads and analyze how they influence the growth process and how they relate to the scoliotic pathomechanism.
In the first part, the analytical formulation of mechanobiological growth developed by Stokes et al. (1990) and Carter et al. (1988) was compared using a finite element model representing a thoracic vertebra as solid elements. Stokesâs model only concerned axial stress, while Carterâs model involved multi-axial stresses. The epiphyseal growth plates were represented using three layers similar to those found in the vertebral bodies: a loading sensitive area, a growth area, and a mineralized area. The two mechanobiological growth models were numerically integrated into the growth plate model. The two models were further used to simulate vertebral growth modulation resulting from different physiological loading conditions applied o
Selection of fusion levels in adolescent idiopathic scoliosis (AIS) using the fulcrum bending radiograph prediction: verification based on pedicle screw strategy
E-Poster - Adolescent Idiopathic Scoliosis: no. 297Utilizing the fulcrum bending radiographic technique to assess curve flexibility to aid in the selection of fusion levels, a prospective radiographic study was performed to assess the safety and effectiveness of pedicle screw fixation with alternate level screw strategy (ALSS) for thoracic AIS. This study suggests that ALSS obtains greater deformity correction than hook and hybrid systems, and improves balance without compromising fusion levels.postprin
'Clinical Triad' findings in Klippel-feil patients
E-Poster - Congenital Deformity: no. 530It has been propagated that Klippel-Feil Syndrome (KFS) is associated with the clinical triad findings (CTF) of short neck, low posterior hairline, and limited range of motion. This study noted that CTFs are not consistently noted in KFS patients. KFS patients with extensive congenitally fused cervical segments were more likely to exhibit one of the components of CTF.postprin
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