| Start Date: | 6/3/2026 | Start Time: | 12:00 PM |
| End Date: | 6/3/2026 | End Time: | 2:00 PM |
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Event Description
BIOMED Master's Thesis Defense
Title:
Development and Stress-Modulated Vertebral Growth Simulation of a Template Finite Element Model of the Pediatric Spine, Ribcage, and Pelvis with Idiopathic Early Onset Scoliosis
Speaker:
Anish Aitha, Master's Candidate
School of Biomedical Engineering, Science and Health Systems
Drexel University
Advisor:
Sriram Balasubramanian, PhD
Professor
School of Biomedical Engineering, Science and Health Systems
Drexel University
Details:
Early onset scoliosis (EOS) is a heterogeneous spinal deformity affecting children under the age of 10, with curve progression driven by asymmetric vertebral growth dictated by the Hueter-Volkmann Law (HVL). Left untreated, EOS can lead to Thoracic Insufficiency Syndrome (TIS), a condition that impairs breathing and thoracic development. While EOS encompasses multiple etiologies, idiopathic EOS accounts for a substantial proportion of cases and is characterized by unpredictable curve progression. Computational finite element (FE) models have been used to simulate growth and predict deformity progression in adolescent idiopathic scoliosis, but limited models exist for idiopathic EOS. Existing models also lack comprehensive anatomy such as the pelvis, ribcage, and sternum. The purpose of this study was to develop a high-quality hexahedral idiopathic EOS osteoligamentous template FE model of the thoracic- lumbar spine with intervertebral discs (IVDs), spinal ligaments, pelvis, and ribcage and simulate ranges of motion (ROMs) through flexion-extension, lateral bending, and axial rotation, and evaluate deformity progression through 12 months of stress-modulated longitudinal growth.
Chest CT scans of a 1-year-old patient with idiopathic EOS were retrospectively obtained from the Children’s Hospital of Philadelphia (CHOP). Thoracic and lumbar vertebrae (T1-L5) and ribs were digitally segmented and reconstructed, then meshed with intervertebral discs and spinal ligaments. The pelvis was adapted from a previously developed AIS FE model, and the sternum and costal cartilage were simplified as beams. Material properties were derived from age-scaled adult values reported in literature. The complete osteoligamentous FE model consisted of 251689 elements and met established hexahedral mesh quality criteria: Jacobian ≥ 0.5 (94%), warpage ≤ 40 (98%), skewness ≤ 60 (98%), minimum angle ≥ 30° (97%), maximum angle ≤ 150° (95%), and aspect ratio ≤ 5 (86%). A ±0.50 N-m moment was applied to T1 and angular displacement of the thoracic (T1-T12) and lumbar (L1-L5) spines were compared against adult cadaveric in vitro data. The FE model matched the regional trends described in the in vitro data, with generally greater angular displacements across all loading modes. Notably, the FE model predicted high thoracolumbar (T12-L1) involvement during lateral bending towards the concavity of the curve (18°) in contrast with lateral bending towards the convexity of the curve (3°). A sensitivity analysis evaluating the effects of IVD stiffness on spinal flexibility suggested that these results likely reflect the structural effects of the idiopathic EOS deformity.
Longitudinal growth was performed using the thermal expansion method in the vertebral bodies of the T1-L5 osteoligamentous FE spine. After antigravitational unloading and gravitational loading, 12 months of growth was simulated using literature-derived normative growth rates modulated by the Von Mises stress across vertebral body regions. After 12 months of simulated growth, the T7-L2 Cobb angle increased by 10°, T1-L5 kyphosis decreased by 6°, apical vertebral (T11 vertebra) wedging increased by 1.2° in the frontal plane and decreased by 0.8° in the sagittal plane, and growth strain accumulated asymmetrically consistent with the HVL. Overall, the idiopathic EOS template FE model predicted deformity progression in idiopathic EOS through stress-modulated longitudinal growth.
The clinical significance of the idiopathic EOS template FE model developed in this study is that it serves as a computational tool for understanding and predicting curve deformity progression in idiopathic EOS, which is a condition with limited clinical data. Furthermore, this template FE model contributes to the shift towards computational tools in pediatric spine orthopedics and could aid clinicians in patient-specific treatment planning for idiopathic EOS patients. Future studies could integrate algorithms to morph the existing spine geometry to patient-specific anatomical landmarks, develop FE models representative of other EOS etiologies, and evaluate the progression of TIS in EOS patients. |
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Location:
Pearlstein Business Learning Center, Room 102, located at 3230 Market Street. Also on Zoom. |
Audience:
Undergraduate StudentsGraduate StudentsFacultyStaff |
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