MRI-based clinical anatomical evaluation of vertebral morphometric changes associated with disc herniation stages at the L4-L5 level

Introduction/Objective. This study aimed to evaluate vertebral body and intervertebral disc morphometry at the L4–L5 level in individuals with lumbar disc herniation, with a particular focus on identifying morphometric parameters relevant to radiological interpretation from a clinical anatomical perspective. Methods. Lumbar MRI scans of 98 individuals aged 40–60 with single-level L4–L5 disc herniation and 184 healthy individuals (defined as subjects with normal discs or disc bulging without protrusion or extrusion) were retrospectively reviewed. Anterior, middle, and posterior morphometric measurements of the L4–L5 intervertebral disc and the L4–L5 vertebral bodies were obtained on standardized sagittal planes and compared between groups as well as between protrusion and extrusion subgroups. Results No significant differences were observed in L4 and L5 vertebral body heights between healthy and pathological groups (p > 0.05). However, anterior, middle, and posterior disc heights at the L4–L5 level were all significantly reduced in the pathological group compared with healthy controls (p < 0.05). Within the pathological group, posterior disc height and the percentage of posterior disc height loss were significantly lower in extruded cases than in protruded cases (p 0.05). In addition, the disc height asymmetry ratio was significantly lower in extruded cases, reflecting a posterior-dominant disc collapse pattern (p < 0.05). Conclusion. While a general reduction in disc height was observed in the pathological group, the decrease in posterior disc height was more pronounced, particularly in extruded cases. The preservation of vertebral body morphometry highlights morphometric changes specific to disc pathology. From a clinical anatomical perspective, posterior disc morphometry may be considered a supportive parameter in the radiological evaluation of lumbar disc herniation.