Evaluations of Computed Tomography Images and Lumbar Specimens in Mimic Operations of Transverse Rotation Laminoplasty for Lumbar Spinal Stenosis

BACKGROUND: Laminectomy is a major method to treat lumbar spinal stenosis (LSS), but it has lots of flaws such as scar tissue can form around the dura again or spinal instability. This study aimed to investigate the feasibility of transverse rotation laminoplasty (TRL) in the treatment of LSS. METHODS: The mimic operations of TRL were performed both in the computerized image processing and on the lumbar specimen. Computed tomography (CT) images were either collected from 80 clinical patients with complaints of lumbago or obtained from 40 sets of lumbar specimens after rebuild of spinal canals. In the CT image processing the heights of the spinous process and laminae at L3–L5 were measured. The total length of the spinous process plus one side laminae after the operation was evaluated and compared with the length of inner margin of pedical before the operation. The areas of the vertebral canal were examined before and after the operation. RESULTS: In the CT images, the height of spinous process of L3, L4 and L5 was 24.74 ± 3.45, 22.68 ± 5.96 and 21.54 ± 4.12 mm respectively, and that of laminae was 23.66 ± 2.32, 22.68 ± 5.36 and 20.99 ± 3.67 mm respectively (P > 0.05). Distance of inner border of pedical of L3, L4 and L5 was 23.01 ± 6.59, 24.65 ± 5.54 and 26.03 ± 7.34 mm respectively, and length of spinous process with laminae of those was 29.76 ± 4.91, 29.31 ± 6.43 and 32.53 ± 5.76 mm respectively (P < 0.05). Preoperative area of spinal canals of L3, L4 and L5 was 299.81 ± 10.09, 297.66 ± 9.54 and 308.22 ± 10.04 mm(2) respectively, and postoperative area was 480.01 ± 9.33, 487.32 ± 8.65 and 501.03 ± 9.12 mm(2) respectively (P < 0.05). In the human lumbar vertebrae specimen, the data similar to the former. CONCLUSIONS: The excised canal posterior was covered, and the lumbar canals enlarged by TRL. The TRL provided a new alternative in the treatment of LSS.