Morphometry of Lumbar Spine- A Holistic Comparative Study between Typical and Atypical Lumbar Vertebrae

Abstract

Introduction: Morphometry of body and neural arch of lumbar vertebrae is very crucial in manufacturing screws, interspinous implants as well as preoperative planning of surgeries involving dorsolumbar spine. Aim: To determine various dimensions of typical and atypical lumbar vertebrae. Materials and Methods: A descriptive osteological study was carried out which included 66 intact adult dry human lumbar vertebrae (53 typical and 13 atypical) which were free of any deformity or pathological features. All the 53 typical vertebrae were randomly obtained. The following parameters were measured with slide callipers- superior transverse diameter and superior anteroposterior diameters of vertebral foramen; transverse diameter, antero-posterior diameter and anterior height of vertebral body; width, height of pedicles; interpedicular distance; maximum thickness of lamina; length of transverse process; maximum length, maximum height and maximum central thickness of spinous process. The data was tabulated and analysed using Microsoft Excel software. Mean and standard deviation was calculated for each parameter. Unpaired t-test was applied and p-value was derived for parameters like width and height of pedicles, thickness of lamina and length of transverse process. The p-value<0.05 were considered as significant. Results: The vertebral foramen (superior transverse diameter20.41±2.54 mm, superior antero-posterior diameter- 13.3±2.04 mm); vertebral body (transverse diameter- 44.43±5.91 mm, antero-posterior diameter- 30.17±3.19 mm, anterior height24.01±1.84 mm); pedicle (width- 10.85±3.94 mm on left side and 11.04±4.01 mm on right side, height- 13.84±4.01 mm on left side and 13.8±1.93 mm on right side, interpedicular distance- 29.17±5.06 mm); lamina (thickness- 6.6±1.36 mm on left side and 6.85±1.34 mm on right side); transverse process (length- 20.94±4.01 mm on left side and 21.51±4.5 mm on right side); spinous process (maximum length- 26.01±3.73 mm, maximum height- 19.92±4.03 mm, maximum central thickness- 6.42±1.41 mm). The mean transverse diameter and antero-posterior diameter of vertebral foramen of atypical lumbar vertebrae were higher than those of the typical lumbar vertebrae and these differences were significant (p-value of 0.0001 for transverse diameter and p-value of 0.005 for antero-posterior diameter). Conclusion: Most of the parameters of atypical lumbar vertebrae were found to be more compared to those of typical lumbar vertebrae. This inference should be kept in mind during fixation of lumbar inter-spinous implants, designing of pedicular screws and spinal grafting.

Keywords

• dimensions
• lumbar vertebral column
• neural arch
• vertebral body