人工椎间盘矢状面覆盖比对颈椎人工椎间盘置换术后椎旁骨化的影响

Influence of artificial disc sagittal coverage ratio on paravertebral ossification after cervical artificial disc arthroplasty

目的探讨Bryan人工椎间盘矢状面覆盖比(SCR)与颈椎人工椎间盘置换术后椎旁骨化(PO)形成的关系。方法回顾性分析2003年12月—2007年12月因颈椎退行性疾病行单节段Bryan人工椎间盘置换术患者临床资料,共71例,所有患者均随访>10年,在术后即刻侧位X线片上测量人工椎间盘SCR。末次随访时,通过CT与X线片结合评估置换节段PO分级。使用多因素logistic回归法分析人工椎间盘SCR、年龄等因素对高等级PO形成的影响。对多因素logistic回归分析的阳性结果采用受试者工作特征曲线及曲线下面积进行检验与量化。结果末次随访时,71例患者中66例出现PO,其中0级5例,1级16例,2级25例,3级7例,4级18例。高等级(34级)PO患者人工椎间盘SCR小于低等级PO(02级)患者,差异有统计学意义(P <0.05)。所有研究的相关因素中,仅人工椎间盘SCR是PO形成的影响因素(比值比0.659,P <0.05)。人工椎间盘SCR预测PO形成的工作特征曲线下面积为0.878(95%置信区间0.7760.981),且计算得出人工椎间盘SCR的最佳判断阈值为95%。结论人工椎间盘SCR是颈椎人工椎间盘置换术后PO形成的影响因素,人工椎间盘过小会造成术后远期高等级PO形成的概率增大,置入的人工椎间盘SCR应尽量> 95%。

Objective To evaluate the correlation between artificial disc sagittal coverage ratio(SCR) and paravertebral ossification(PO) after cervical artificial disc arthroplasty. Methods Clinical data of 71 patients underwent single segmental Bryan cervical disc arthroplasty from December 2003 to December 2007 were analyzed retrospectively. All the patients were followed for >10 years. The SCR was measured at lateral roentgenograph immediately after operation. The grades of PO were evaluated by CT and roentgenograph at the final follow-up. Logistic regression was used to analyze the effect of the artificial disc SCR,age and other factors on the occurrence of high grade PO. The receiver operating characteristic curve and area under the curve was used to evaluate the significant results of logistic regression and calculate the optimal diagnostic value. Results At the final follow-up,PO was detected in 66 patients. Grade 0,1,2,3,and 4 PO occurred in 5,16,25,7,and 18 patients respectively. Compared with patients with low grade(0 - 2) PO,the artificial disc SCR was smaller in patients with high grade(3 - 4) PO,and the difference was statistically significant(P < 0.05). In all relative factors studied,only the artificial disc SCR was an influential factor of the PO formation(odds ratio 0.659,P < 0.05). The area under the receiver operating characteristic curve of artificial disc SCR to predict PO formation was 0.878(95% confidence interval 0.776 - 0.981),and the optimal diagnostic threshold was 95%. Conclusion The artificial disc SCR is an influencing factor for the formation of PO after cervical artificial disc arthroplasty. The smaller artificial disc SCR will cause the higher grade of PO in the long-term follow-up, and especially the artificial disc SCR should be as high as 95%.