The evaluation of normal radiographic measurements of the lumbar spine in young to middle aged Indian females in Durban
To evaluate the lumbar lordosis, lumbosacral angle, lumbosacral disc angle, lumbosacral lordosis angle, intervertebral disc angles and heights, interpedicular distances, sagittal canal diameters and the lumbar gravity line (selected radiographic parameters) in young to middle aged Indian females in Durban. To determine any association between the selected radiographic parameters and the age of the subjects, weight, height and body mass index of the subjects, occupation, smoking, previous pregnancy and leg length inequality (selected anthropometric and demographic factors). Methods: Sixty healthy, asymptomatic, young to middle aged, Indian females were recruited for this study. All subjects underwent a case history, a physical examination and radiographic evaluation (AP and lateral views) of the lumbar spine. SPSS version 15.0 (SPSS Inc., Chicago, Ill, USA) was used to analyze the data. Results: The mean (± SD) of the lumbar lordosis, lumbosacral angle, lumbosacral disc angle and lumbosacral lordosis angle was 49º (± 6º), 39º (± 8º), 12º (± 5º) and 143.2º (± 5º) respectively. For the lumbar intervertebral disc angles at L1-L2, L2-L3, L3-L4, L4-L5 and L5- S1 levels, the mean (± SD) was 6º (± 2º), 8º (± 2º), 10º (± 3º), 12º (± 4º) and 12º (± 5º) respectively. The anterior and posterior intervertebral disc heights at the respective vertebral levels were: L1-L2: anterior: 8 mm (± 2), posterior 5 mm (± 2); L2-L3: anterior: 10 mm (± 2), posterior 5 mm (± 2); L3-L4: anterior: 12 mm (± 2), posterior 5 mm (± 2); L4-L5: anterior: 14 mm (± 3), posterior 5 mm (± 2) and L5-S1: anterior: 13 mm (± 4), posterior 6 mm (± 2). The mean (± SD) of the interpedicular distance at the L1, L2, L3, L4 and L5 vertebral levels was 23 mm (± 2), 24 mm (± 2), 25 mm (± 2), 27 mm (± 2) and 31 mm (± 3) respectively. For the sagittal canal diameter at the L1, L2, L3, L4 and L5 vertebral levels, the mean (± SD) was 20 mm (± 5), 21 mm (± 3), 21 mm (± 3), 21 mm (± 3) and 19 mm (± 3) respectively. The lumbar gravity line intersected the sacrum in 67.3% of the subjects. In 29.1% of the subjects, the lumbar gravity line passed anterior to the sacrum while in 3.6% of the subjects, it passed posterior to the sacrum. iv A significant association was found between lumbar lordosis and the height of the subjects in this study (p = 0.004). A decrease in the intervertebral disc height at L5-S1 was associated with smoking (p = 0.005). A decrease in the intervertebral disc height at L4-L5 was associated with previous pregnancy (p = 0.016). Body mass index of 26–30 kg.m-2 was significantly associated with an increase in the intervertebral disc angles at L3-L4 (p = 0.028) and L4-L5 (p = 0.031). A decrease in the L5-S1 intervertebral disc angle was also significantly associated with smoking (p = 0.023). There was a significant association between previous pregnancy and an increase in the intervertebral disc angle at L3-L4 (p = 0.016). A significant association was found between the age of the subjects and the L5-S1 intervertebral disc angle (p = 0.007). Specifically it was the 23–27 year group and 33–37 year group who were significantly different from each other (p = 0.033). Conclusion: Similarities and differences were found in the mean values of the radiographic parameters measured in this study and those reported in the literature. A number of the selected anthropometric and demographic factors were associated with some of the lumbar radiographic parameters. Further studies are required to establish the clinical significance of these findings.