颈椎人工椎间盘置换术患者选择与异位骨化形成的相关性分析

 目的 分析颈椎人工椎间盘置换术患者选择与术后异位骨化形成的相关性。方法 回顾性分析2003年12月至2008年12月,48例接受Bryan人工颈椎间盘置换术且随访时间超过5年的患者资料,男21例,女27例;年龄20~53岁,平均42岁;脊髓型颈椎病34例,神经根型颈椎病14例;单节段置换术38例,包括C_3-4 3例、C_4-5 5例、C_5-6 28例、C_6-7 2例;双节段置换术9例,包括C_4-5、C_5-6 4例、C_5-6、C_6-7 5例;三节段置换术1例（C_3-4、C_4-5、C_5-6）;共59个手术节段。在术后颈椎侧位X线片上使用McAfee分级法评价异位骨化形成。使用Logistic回归分析患者性别、术前手术节段活动度、置换节段脊柱功能单位曲度、置换节段与相邻节段椎间隙高度比值等因素与术后异位骨化形成的关系。对阳性结果及其选择阈值采用接受者操作特征（receiver operating characteristic, ROC）曲线及曲线下面积（area under the ROC curve, AUC）进行检验和量化分析。结果 48例患者术后均获得5年以上随访,随访时间60~120个月,平均70.3个月。术后59个节段中,20个出现异位骨化,发生率为33.9%（20/59）。患者性别、节段活动度、置换节段脊柱功能单位曲度和术前置换节段椎间隙高度这四方面因素中,仅术前置换节段与相邻节段椎间隙高度比值与术后异位骨化的形成具有显著相关性。通过ROC曲线分析该因素的AUC为0.813,95%置信区间为0.666~0.959,据此计算出病变节段与相邻节段椎间隙高度比值的临床最佳判断阈值为0.9。结论 患者选择相关临床因素中的术前置换节段椎间隙高度与术后异位骨化形成具有相关性;针对可变旋转中心的Bryan颈椎人工椎间盘假体,术前病变节段椎间隙高度较相邻节段丢失超过10%者不适合行人工椎间盘置换术。

The correlation between patient selection and heterotopic ossification after cervical artificial disc replacement

Objective To analysis the correlation between patient selection and heterotopic ossification (HO) after cervical artificial disc replacement. Methods Data of 48 patients with cervical spondylosis (34 cervical spondylotic myelopathy and 14 nerve-root type) who had undergone Bryan cervicadisc replacement from December 2003 to December 2008 were reviewed retrospectively, and all the patients had been followed up for more than 5 years. There were 21 males and 27 females with an average age of 42 years old (range, 20-53 years). There were 38 single level replacement (C_3-4 3 cases, C_4-5 5 cases, C_5-6 28 cases, C_6-7 2 cases), 9 double level replacement (C_4-5, C_5-6 4 cases; C_5-6, C_6-7 5 cases) and 1 three level replacement (C_3-4, C_4-5, C_5-6) as a total of 59 surgical segments. The occurrence of HO was defined by McAfee classification on cervical lateral X-ray. Four factors were used in patient selection including gender, range of motion (ROM) of the target level, alignment of the functional spine unit (FSU) of the index level, and the disc height ratio between surgical level and the adjacent levels. The correlation between these four factors and HO was evaluated by logistic regression. The receiver operating characteristic (ROC) curve and area under the ROC curve were used to evaluate the significant result of logistic regression and the optimal diagnostic value. Results 48 patients were all followed up for an average period of 70.3 months (range, 60-120 months). The occurrence rate in this study was 33.9% (20/59 segments). Only one factor, the disc height ratio of the target level and its adjacent levels, presented statistical correlation with HO. ROC analysis showed that the area under the ROC curve of disc height ratio was 0.813 and the optimal diagnostic threshold was 0.9. Conclusion The disc height ratio of the target level and adjacent levels was the only patient selective factor correlated with the occurrence of HO. For those with disc height loss exceeding 10% comparing to adjacent levels, it is not indicated for cervical artificial disc replacement with Bryan prosthesis.