A long-term clinical study of facet joint degeneration after cervical artificial disc replacement

English Keywords:Cervical degenerative disease  Artificial disc replacement  Facet joint degeneration  Segmental range of motion

English Abstract:

  【Abstract】 Objectives: To evaluate the risk factors of single segment cervical facet joint degeneration after artificial cervical disc replacement(ACDR), and the influence of facet joint degeneration on cervical segmental motion and clinical symptoms. Methods: We performed a retrospective analysis on 70 patients with cervical degenerative disease, who underwent single-level Bryan cervical artificial disc replacement in our department from January 2003 to January 2008. A 10-year clinical follow-up was conducted. There were 43 males and 27 females. The mean postoperative follow-up time was 129±14(105-165) months. The average age was 55.7±8.4(37-76)years. The cervical spine segment range of motion (ROM) was measured using cervical dynamic position X-ray film at preoperation, postoperation and final follow-up. The degree of cervical facet joint de?鄄generation was assessed using CT images according to the quantitative scoring system of cervical small joints preoperatively and at final follow-up. Clinical evaluation including the Japanese Orthopaedic Association(JOA) score, neck disability index (NDI) were performed in the preoperative evaluation and final follow-up. Odom standard grading and visual analogue scale (VAS) were performed at final follow-up. Results: Before surgery, 41 patients had none or mild degeneration of the facet joints, 28 patients had moderate degeneration, and 1 patient had severe degeneration. At final follow-up, there were 16 patients with mild degeneration of facet joints, 35 patients with moderate degeneration, and 19 patients with severe joint degeneration. The small joint degeneration was found to be correlated with gender and age using Szpilman bivariate correlation test. Male was a risk factor for the facet joint degeneration. There was no correlation between surgical segment and the degree of facet joint degeneration. There was no statistically significant difference in the preoperative and final follow-up segment ROM (9.7°±4.5° vs 8.7°±5.4°, P>0.05), and no statistically significant difference in the overall cervical ROM (46.5°±15.2° vs 46.1°±13.0°, P>0.05). There was a statistically significant difference in the score of facet joint degeneration between the preoperative and final follow-up (1.5±0.8 vs 2.6±1.2, P<0.05). There was a significant difference in JOA score between preoperative and final follow-up(13.5±1.9 vs 16.5±1.4, P<0.05). There was a statistical difference in NDI score between preoperative and final follow-up (0.27±0.08 vs 0.16±0.10, P<0.05). At final follow-up, there were 35 patients with excellent Odom grading, 29 patients with good Odom grading, 6 patients with normal Odom grading, and no patients with poor Odom grading. VAS score was 3.47±1.55 at final follow-up. The degree of facet joint degeneration at final follow-up was negatively correlated with the ROM of the operative segment and the overall cervical spine (P<0.05), and it was not significantly correlated with JOA, NDI, Odom grading and VAS. Conclusions: Elder age and male are the risk factors of facet joint degeneration. There was a degree of degeneration of facet joints after long-term follow up of ACDR surgery. There was a negative correlation between the degree of facet joint degenera?鄄tion and the degree of cervical postoperative mobility. The degree of facet joint degeneration was not related to the clinical symptom.