Objective: To probe the clinical significance of space occupation of lumbar protruded nucleus pulposus (PNP) in vertebral canal.
Methods: Materials of tridimentional ultrathin scanning computed tomography (CT), plain and flexion-extension dynamic radiograph on lumbar spine in 44 patients of lumbar intervertebral disc protrusion and 73 asymptomatic subjects (as control, including 22 cases with PNP but without symptoms) were observed, analysed and compared in volume, surface area, relative space occupation of PNP inside spinal canal, structure deformation and mobility of lumbar spine, and their difference and relevance.
Results: The rate of asymptomatic lumbar disc protrusion in the control group was up to 30.1%. The volume, surface area and relative space occupation of PNP inside spinal canal in the patients group were significantly higher than those in the control group. Although the structure was more deformed and mobility of lumbar spine more limited in the patients group before and after treatment than those in the control group, as compared with those subjects with asymptomatic PNP, the difference was insignificant.
Conclusion: (1) Relative space occupation of PNP inside spinal canal could be usually digested by compensation system of spinal column, however, there is no final conclusion reached about the limit of compensation system; (2) Relatively bigger PNP may reduce the structure compensation capability of lumbar spine, which will result, sometimes, in a mechanical disorder of lumbar spine and nerve root irritation.