Exploring vertebral bone density changes in a trunk with adolescent idiopathic scoliosis: a mechanobiological modeling investigation of intact and unilaterally paralyzed muscles

Abstract

This study aimed to elucidate the vertebral bone density variations associated with adolescent idiopathic scoliosis (AIS), specifically examining the impact of unilateral muscle paralysis using an integrated approach combining Frost’s Mechanostat theory, a three-dimensional subject-specific finite element model and a musculoskeletal model of the L2 vertebra. The findings revealed a spectrum of bone density values ranging from 0.29 to 0.31 g/cm3, along with vertebral micro-strain levels spanning from 300 to 2200, consistent with existing literature. Furthermore, the ratio of maximum von Mises stress between the concave and convex side in the AIS model with intact muscles was approximately 1.08, which decreased by 4% due following unilateral paralysis of longissimus thoracis pars thoracic muscle. Overall, this investigation contributes to a deeper understanding of AIS biomechanics and lays the groundwork for future research endeavors aimed at optimizing clinical management approaches for individuals with this condition.

Keywords:

• Bone remodeling
• spinal deformity
• muscle weakening
• adolescent idiopathic scoliosis
• finite element analysis

Author contributions

All authors contributed to the study design. Mohammad Hosseinzadehposti conducted the analysis and validation of the FE models, carried out the research, prepared the results, wrote the initial draft of the results section, and contributed to the discussion part. Zeinab Kamal was responsible for conceptualization, material preparation, data visualization, interpreting the results, initial drafting of the introduction and discussion sections, revision and proofreading of the manuscript, as well as supervising the work. Mohadese Rajaeirad performed the vertebral modeling, visualized the figures, wrote the initial draft of the method section, and contributed to the discussion part. All authors have read and approved the final version of the manuscript.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Ethical approval

The Yazd Medical University ethics committee gave its approval to the study, and the participants provided their written informed permission.

Additional information

Funding

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.