The human vertebral column undergoes continuous structural remodeling throughout life, influenced by genetic, biomechanical, and age-related factors. Among these, aging has been shown to significantly impact vertebral morphology, resulting in alterations that may predispose individuals to spinal instability, pain, and increased risk of fractures (1,2). With advancing age, the vertebral bodies often exhibit reductions in height and width, along with cortical thinning and trabecular bone loss (3).

Several studies have documented that vertebral compression fractures, particularly in the thoracolumbar region, are common among the elderly and often go undiagnosed due to subclinical presentation (4). These fractures are associated with decreased vertebral dimensions and bone mineral density, which are strongly age-related phenomena (5). Understanding how vertebral dimensions vary across different age groups is essential for the early detection of degenerative spinal changes and for planning orthopedic, rehabilitative, and preventive interventions (6).

Radiological modalities such as computed tomography (CT) provide high-resolution cross-sectional imaging that allows precise measurement of vertebral body dimensions in vivo. CT-based morphometric analysis can help quantify age-related changes in vertebral height, anterior-posterior (AP) diameter, and transverse (TR) diameter, facilitating the identification of early degenerative trends (7,8).

Despite extensive research in spinal pathology, limited data exist on normative age-based vertebral measurements in asymptomatic individuals across different decades of life. This study was therefore designed to assess vertebral body dimensions using cross-sectional radiological data, aiming to identify patterns of morphological changes associated with aging.

Study Design and Setting:
This was a retrospective, cross-sectional study conducted at tertiary care teaching hospital.

 Sample Selection:
CT scan records of 150 individuals aged between 20 and 80 years were randomly selected from the hospital’s radiology database. Participants were grouped into three age-based cohorts:

• Group I: 20–39 years
• Group II: 40–59 years
• Group III: 60–80 years

Each group comprised 50 participants. Inclusion criteria were individuals undergoing thoraco-lumbar CT for non-spinal indications (e.g., abdominal evaluation) and without evidence of vertebral fractures, spinal deformities, tumors, or previous spinal surgery. Cases with poor image quality or known metabolic bone disease were excluded.

Imaging Protocol:

All CT scans were performed using a 128-slice multidetector CT scanner. Scans included the thoracolumbar spine, and image slices with a thickness of 1 mm were used for analysis. Multiplanar reconstruction (MPR) was applied for accurate visualization of vertebral structures.

 Measurement Technique:
Measurements were taken at vertebral levels T12, L1, and L2 using digital calipers within the CT viewing software. Three parameters were assessed:

• Vertebral Body Height (VBH): Maximum vertical height of the vertebral body in the midsagittal plane.
• Anterior-Posterior (AP) Diameter: Distance from the anterior to posterior cortical margins in the mid-vertebral transverse plane.
• Transverse (TR) Diameter: Maximum horizontal width measured from lateral cortex to lateral cortex.

Each measurement was performed twice by two independent radiologists to reduce interobserver variation, and the average was considered for final analysis.

 Statistical Analysis:

Data were compiled in Microsoft Excel and analyzed using SPSS version 26.0. Descriptive statistics (mean ± standard deviation) were calculated for all variables. Comparisons between age groups were made using one-way ANOVA followed by post hoc Tukey tests. A p-value < 0.05 was considered statistically significant.

The study analyzed CT scan measurements of 150 individuals across three age groups to assess vertebral body dimensions. The mean vertebral body height (VBH), anterior-posterior (AP) diameter, and transverse (TR) diameter were calculated for T12, L1, and L2 vertebrae in each group.

A consistent decrease in vertebral dimensions was observed with advancing age. Group I (20–39 years) had the highest mean values, followed by Group II (40–59 years), while Group III (60–80 years) demonstrated the lowest dimensions across all parameters.

At the L1 vertebral level, the average VBH in Group I was 28.2 ± 1.5 mm, which declined to 26.1 ± 1.8 mm in Group II and further reduced to 23.4 ± 1.7 mm in Group III. A similar downward trend was noted in both AP and TR diameters. The AP diameter at L1 decreased from 33.5 ± 1.9 mm in Group I to 29.7 ± 2.1 mm in Group III. The TR diameter showed a reduction from 41.8 ± 2.2 mm (Group I) to 36.5 ± 2.4 mm (Group III). These differences were statistically significant (p < 0.001) as shown in Table 1.

Table 1: Mean Vertebral Dimensions (mm) at L1 Level Across Age Groups

The pattern was consistent across T12 and L2 vertebrae, suggesting a generalized age-related reduction in vertebral body size. No significant gender differences were observed in this sample set.

The present study aimed to quantify age-related changes in vertebral body dimensions at thoracolumbar levels using cross-sectional radiological data. Our findings demonstrated a statistically significant reduction in vertebral body height, anterior-posterior diameter, and transverse width with advancing age. These results align with previous studies that suggest vertebral geometry changes as a natural consequence of aging, influenced by mechanical loading, reduced bone mineral density, and degenerative changes in vertebral structure (1,2).

Vertebral height loss is among the earliest and most prominent age-related spinal alterations. It has been closely associated with intervertebral disc degeneration, reduced trabecular bone mass, and microstructural deterioration of the vertebral body (3,4). In this study, the average reduction in vertebral body height from the youngest to the oldest group was approximately 4.8 mm at the L1 level, consistent with earlier morphometric assessments (5,6). These dimensional changes may affect spinal biomechanics, increasing the risk for kyphosis, spinal instability, and vertebral compression fractures in the elderly (7).

The observed decrease in transverse and anterior-posterior diameters may reflect age-related cortical bone thinning and alterations in vertebral loading patterns. Previous investigations utilizing CT and MRI have reported similar reductions, particularly in postmenopausal women, further indicating the influence of hormonal factors and osteoporosis on vertebral integrity (8,9). Structural remodeling and bone resorption are particularly pronounced at the endplates and anterior aspects of the vertebrae, explaining the wedge-shaped deformities commonly seen in aging spines (10).

Although our study did not differentiate based on sex, some literature suggests that vertebral size reduction is more rapid in females after the sixth decade due to decreased estrogen levels, leading to trabecular connectivity loss and cortical thinning (11). Moreover, changes in vertebral morphology are often asymptomatic, leading to underdiagnosis until an acute event like a fracture occurs (12,13). Early radiological screening and morphometric evaluations can therefore help in preventive risk stratification and treatment planning, especially in osteoporotic patients (14).

The study's strength lies in its use of high-resolution CT data and consistent measurement protocols across all age groups. However, certain limitations should be acknowledged. The cross-sectional design does not allow for direct observation of longitudinal changes within individuals. Additionally, vertebral bone density was not measured, which may have offered further insight into the structural integrity of aging vertebrae (15).

This study demonstrates that vertebral body dimensions—height, anterior-posterior, and transverse diameters—decrease significantly with age. These morphological changes may contribute to increased risk of spinal instability and fractures in the elderly, highlighting the importance of early radiological assessment for preventive care and clinical decision-making.

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