Modeling of intervertebral discs’ parameters of the lumbar spine base on somatometric data

The relevance of the study arises from the high prevalence of spinal column pathology and the rapid advancement of diagnostic technologies, which necessitate the refinement of criteria for identifying changes in the structural components of the spine, particularly one of its most vulnerable elementsт – the intervertebral discs. The reliance on subjective criteria for assessing intervertebral discs during magnetic resonance imaging (MRI) or computed tomography (CT) highlights the need for more objective, quantitative criteria to evaluate intervertebral disc changes. The aim of the study was to develop an optimal, practical model for calculating the total size index of intervertebral discs based on external body parameters, applicable in clinical practice, and to validate its effectiveness. To achieve this goal, lumbar spine MRI was performed on young women aged 16 to 26 years who were native residents of the Vinnytsia region. The main group consisted of 80 participants, including 52 young women aged 16-20 years and 28 women aged 21-26 years; the validation group included 65 females aged 16-26 years. Anthropometric measurements, including height and body weight, were recorded for all participants. Using data from the main group, mathematical modeling was conducted to determine the total size of lumbar intervertebral discs. The modeling process employed stepwise regression analysis based on somatodisc coefficients of individual intervertebral discs and anthropometric parameters. As a result, a model was developed to calculate somatodisc coefficients using body height and weight. Further algebraic transformations of the somatodisc coefficient yielded a formula for calculating individualized total disc size indicators, integrating vertical, sagittal, and transverse dimensions. The predictive accuracy of the obtained models ranged from 85 % to 91 %. When the actual total size measurements of intervertebral discs in the main group were compared to the mathematically modeled values, deviations did not exceed ±10 %. This mathematical model for calculating the total size of lumbar intervertebral discs based on somatometric data enables the determination of individualized normative metrics and the objective identification of early degenerative disc changes. When comparing clinical visual assessments of intervertebral disc changes using Pfirrmann grading with mathematical evaluations in the validation group, agreement was observed in 91 % of cases. Discrepancies were identified in 9 %, necessitating further analysis to prevent underdiagnosis or overdiagnosis of intervertebral disc changes. Thus, mathematical modeling serves as a tool for determining individualized normative metrics. The proposed mathematical models for calculating the total size of intervertebral discs based on body height and weight represent a powerful supplement to existing criteria for intervertebral disc assessment.