Authors response to letter to the editor regarding “Vertebral growth modulation by posterior dynamic deformity correction device in skeletally immature patients with moderate adolescent idiopathic scoliosis”

2021 ◽  
Author(s):  
Yizhar Floman
Keyword(s):  
Adolescent Idiopathic Scoliosis ◽  
Idiopathic Scoliosis ◽  
Deformity Correction ◽  
Skeletally Immature ◽  
Growth Modulation ◽  
Letter To The Editor ◽  
Vertebral Growth

Simulation of Progressive Deformities in Adolescent Idiopathic Scoliosis Using a Biomechanical Model Integrating Vertebral Growth Modulation

2002 ◽  
Vol 124 (6) ◽  
pp. 784-790 ◽  
Author(s):  
I. Villemure ◽  
C. E´. Aubina ◽  
J. Dansereau ◽  
H. Labelle
Keyword(s):  
Finite Element ◽  
Adolescent Idiopathic Scoliosis ◽  
Idiopathic Scoliosis ◽  
Biomechanical Model ◽  
Element Model ◽  
Axial Rotation ◽  
Growth Cycle ◽  
Growth Modulation ◽  
Growth Plates ◽  
Vertebral Growth

While the etiology and pathogenesis of adolescent idiopathic scoliosis are still not well understood, it is generally recognized that it progresses within a biomechanical process involving asymmetrical loading of the spine and vertebral growth modulation. This study intends to develop a finite element model incorporating vertebral growth and growth modulation in order to represent the progression of scoliotic deformities. The biomechanical model was based on experimental and clinical observations, and was formulated with variables integrating a biomechanical stimulus of growth modulation along directions perpendicular (x) and parallel (y, z) to the growth plates, a sensitivity factor β to that stimulus and time. It was integrated into a finite element model of the thoracic and lumbar spine, which was personalized to the geometry of a female subject without spinal deformity. An imbalance of 2 mm in the right direction at the 8th thoracic vertebra was imposed and two simulations were performed: one with only growth modulation perpendicular to growth plates (Sim1), and the other one with additional components in the transverse plane (Sim2). Semi-quantitative characterization of the scoliotic deformities at each growth cycle was made using regional scoliotic descriptors (thoracic Cobb angle and kyphosis) and local scoliotic descriptors (wedging angle and axial rotation of the thoracic apical vertebra). In all simulations, spinal profiles corresponded to clinically observable configurations. The Cobb angle increased non-linearly from 0.3° to 34° (Sim1) and 20° (Sim2) from the first to last growth cycle, adequately reproducing the amplifying thoracic scoliotic curve. The sagittal thoracic profile (kyphosis) remained quite constant. Similarly to clinical and experimental observations, vertebral wedging angle of the thoracic apex progressed from 2.6° to 10.7° (Sim1) and 7.8° (Sim2) with curve progression. Concomitantly, vertebral rotation of the thoracic apex increased of 10° (Sim1) and 6° (Sim2) clockwise, adequately reproducing the evolution of axial rotation reported in several studies. Similar trends but of lesser magnitude (Sim2) suggests that growth modulation parallel to growth plates tend to counteract the growth modulation effects in longitudinal direction. Overall, the developed model adequately represents the self-sustaining progression of vertebral and spinal scoliotic deformities. This study demonstrates the feasibility of the modeling approach, and compared to other biomechanical studies of scoliosis it achieves a more complete representation of the scoliotic spine.

953 Role of Routine Preoperative Echocardiograms in Adolescent Idiopathic Scoliosis Patients undergoing Deformity Correction Surgery

2021 ◽  
Vol 108 (Supplement_2) ◽  
Author(s):  
A Hassan ◽  
S Shah ◽  
M Patel
Keyword(s):  
Adolescent Idiopathic Scoliosis ◽  
Idiopathic Scoliosis ◽  
Clinical Assessment ◽  
Clinical Symptoms ◽  
Deformity Correction ◽  
Cost Effective ◽  
Cardiovascular Complications ◽  
Anterior Correction ◽  
Perioperative Complication ◽  
Clinical Records

Abstract Introduction Patients with Adolescent Idiopathic Scoliosis (AIS) are often noted to have routine preoperative Echocardiograms (ECHO). The prevalence of ECHO abnormalities and their impact on perioperative outcome is not clear, especially balancing against its costs. The study aims at identifying the significance of routine preoperative ECHO for AIS patients. Methodology Clinical records of 295 adolescent AIS patients, >10years age (mean 15.64years), who underwent primary posterior corrective surgery in a tertiary spinal centre, between 2015-2020, were reviewed. Patients with revision surgery, anterior correction, syndromic/neuromuscular scoliosis and/or pre-existent known cardiac comorbidities were excluded. Results 139(47%) patients had preoperative ECHO. 21(15%) patients showed echocardiographic abnormalities (11 trivial valvular abnormalities, 5 mild root dilatation, 3 mild pericardial effusion and 2 septal defects). None of these patients showed any clinical symptoms/signs or required Cardiology assessment; and none had perioperative cardiovascular complications. Conversely, four(1.36%) patients demonstrated auscultatory murmurs on preoperative clinical assessment. None reported any perioperative complication. The average known cost of an echocardiogram was noted to be £363. Conclusions Routine preoperative Echocardiogram for all AIS patients is not recommended or deemed cost-effective. Positive clinical assessment finding could be used as a screening tool for performing ECHO in AIS patients.

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