Study Of Lumbar Vertebrae Morphology Using Multi-Detector Computed Tomography

Abstract

The objectives of this descriptive analytical study are to study the normal morphometric measurements of the lumbar spine, as well as to establish a reference values for adult individuals of both genders relevant to the Jazan population (KSA). However, it includes the pedicle dimensions ,vertebral body , spinal canal, vertebral corpus , chord length as well as pedicle angles from the levels of first lumber vertebra (L1) to fifth lumbar vertebra (L5) using Multi detector Computed Tomography (MDCT). The study sample included 200 Jazan adult participants (100 were males and 100 were females). The participants’ lumbar vertebrae, pedicles body and canal from (L1 to L5) were evaluated .The selected sample were those who underwent CT lumbar spine and abdominal CT scans done for various reasons, at governmental hospitals Jazan region, pathological cases were excluded. The participants age ranged from 19-75 years old (with the mean of 41.77 years), during the period from March 2016 to July 2020. The two thousand pedicles, one thousand normal lumbar vertebrae (L1 to L5) were analyzed using DICOM viewer for their width, height and length of the pedicles dimensions as well as pedicle axis length. Pedicle angles were also been measured including transverse and sagittal angles. Vertebral body width, depth and height were measured in addition to spinal canal width and spinal canal depth as well as pedicle index, pedicle ratio (CT ratio) and spinal canal ratio. The mean values of pedicle width of the right and left was found to be gradually increased from L1 to L5 level in both genders. The mean pedicle width in males was (8.39 ± 1.23) mm and in females was 8.47 ± 1.17 mm , the measurement demonstrated that there was significant different between males and females participant(p≤ 0.05) for L3. Results also demonstrated that Pedicle width measurements at L5 was significantly larger in older age than in younger age with no significant differences were found between the mean pedicle width for older and younger ages . Results conceived that there was no statistical significant difference found between the gender regarding pedicle height and spinal canal width and chord length. Regarding age the study demonstrated statistically significant relation between older and younger ages at L1,L2 and L3 for the transverse pedicle angle(TPA). The angle of inclination showed that the lumbar vertebrae increased gradually from L1 to L5 in both genders . The largest (TPA) was located at female L5 ((30.70 o) and the smallest (TPA) was located at female L1 (18.49 o) and the mean (TPA) in the older age was larger than the mean (TPA) in the younger age with highly significant differences at (p ≤ 0.05) being depicted at all vertebral levels L1to L5. The largest sagittal pedicle angles (SPA) was found in both genders at L5 (18.01o) and L5 (17.45 o) respectively, and the lowest (SPA) was found in males and females at L1 (14.09 o) and L1 (13.97 o) respectively. The study reveals that there is no significant difference between gender regarding sagittal pedicle angles (SPA). The largest mean value in (mm) for the variable vertebral body width (VBW) was seen at vertebral level L5 in both males (43.97±3.09) and females (43.57±2.51) and the least was at vertebral level L1 in both males (33.29±2.80) and females (32.90±2.54) with statistically significant difference between genders at L3 and L4. Nevertheless, the results suggest that the average mean values for the vertebral body depth (VBD) was higher in males than in females with highly significant difference between gender at all vertebral levels with exception of L5. There is no statically significant difference between genders regarding the spinal canal depth (SCD) at each vertebral levels. The pedicle index (PI ratio) demonstrated that there was gradually increasing from L1 to L5 and the results among genders conceived that pedicle index ratio were greater in females than males at each lumbar level with exception of L1, which was greater in males. The pedicle index curve is similar to both the PDH curve and the PDW curve, especially at lumbar levels of L1–L3. PDW curve demonstrated positive linear relationship with Pedicle index and PDH curve demonstrated negative linear relationship with Pedicle index, whereas in the measurements of pedicle ratio were gradually increased from L1 to L5; however, that pedicle ratio were greater in females than males at each lumbar level except for L1 which was greater in males. The pedicle ratio curve was similar to the PDW curve than the VBW curve, especially at lumbar levels of L1–L2, and the PDW curve depicted highly positive linear relationship with Pedicle ratio and VBW curve demonstrated negative linear relationship with Pedicle ratio. Regarding the spinal canal ratio, it demonstrated that the ratio between the width of spinal canal and lumbar vertebral body was 0.6 at L1, L2 and L3 but it becomes 0.5 at L4 and 0.4 at L5. The ratio of the spinal canal demonstrated that there it was gradually decreasing from L1 to L5. This ratio has also demonstrated that the spinal canal ratio was similar to the SCW curve than the VBW curve, along lumbar vertebral levels of L1–L5, SCW curve demonstrated a positive linear relationship with spinal canal ratio and VBW curve depicted no linear relationship with spinal canal ratio. A Local reference values of lumbar vertebral measurements was established for Saudi-Jazan population. These data might be helpful for the orthopedic surgeons dealing with lumbar vertebral surgery particularly the transpedicular fixation in choosing the suitable threaded screw that can be safely accommodated by the pedicle as orthopedic surgeons should therefore be aware of racial disparities on pedicular parameters.