MATERIAL and METHODS: Twenty-four rabbits were randomly selected for X-ray, computerized tomography (CT), and magnetic resonance imaging (MRI) at 2, 6, and 12 weeks post operation. Moreover, their L3/4, L4/5, and L5/6 intervertebral discs were randomly selected as the untreated, annulus puncture, and nucleoplasty groups, respectively. Changes in disc height index (DHI%) and MRI grade were measured and compared. CT three-dimensional reconstruction was used to evaluate adjacent bone endplate changes.

RESULTS: The untreated group?s DHI% decreased slightly at different time points (p>0.05), while that of the nucleoplasty and annulus puncture groups decreased progressively (p<0.05). At six weeks post operation, the nucleoplasty group?s DHI% was significantly lower than that of the annulus puncture group (p<0.05), with mild osteosclerosis and local rough changes in the endplate. At 12 weeks post operation, a ?bone bridge? connection was observed in the nucleoplasty group. There was no significant difference in MRI grade between the untreated and annulus puncture groups at different time points (p>0.05). MRI grades of the intervertebral disc in the nucleoplasty and annulus puncture groups showed a progressive increase (p<0.05). Compared with the annulus puncture at the same time point, the nucleoplasty group?s MRI grade of the intervertebral disc was significantly higher (p<0.05). Thus, damage caused by an annulus puncture can lead to progressive degeneration of the lumbar disc.

CONCLUSION: Nucleoplasty may have a cumulative effect with the injury of the annulus puncture. Clinicians need to comprehensively consider advantages and disadvantages of nucleoplasty, strictly grasp indications of treatment, and prevent longterm complications. Keywords : Nucleoplasty, Complications, Lumbar disc, X-ray, Rabbits