颈椎前路融合术后邻近节段退变的临床研究

Clinical research on adjacent segment degeneration after anterior cervical fusion

目的研究颈椎前路融合术后邻近节段退变（adjacent segment degeneration,ASD）的发生率及其对临床疗效的影响。方法对2008年5月至2013年5月,于我院行颈椎前路融合术治疗颈椎病的60例患者进行临床及影像学评价,其中男32例,女28例;年龄41~77岁,平均（57.25±8.52）岁;单节段融合10例,双节段融合26例,3节段融合20例,4节段融合4例。所有患者在术前及末次随访时进行疼痛视觉模拟评分（visual analogue scale,VAS）、日本骨科学会（Japanese Orthopaedic Association,JOA）及颈椎功能障碍指数（neck disability index,NDI）。在颈椎X线上测量颈椎前凸角、邻近节段椎间隙高度、邻近节段骨赘大小;在颈椎MRI上测量邻近节段椎管矢状径及评估邻近节段椎间盘Miyazaki退变分级。统计并分析随访时ASD的发生率及其对临床疗效的影响。结果本组随访2-7年,平均（3.93±1.76）年。末次随访时颈椎前凸角较术前有明显改善（P〈0.05）;上位邻近节段椎间隙高度较术前无明显变化（P〉0.05）,下位邻近节段椎间隙高度较术前明显减小（P〈0.05）;上、下邻近节段骨赘较术前有明显增大（P〈0.05）;上、下邻近节段椎管最大矢状径较术前有明显减小（P〈0.05）;上、下邻近节段椎间盘Miyazaki分级均有明显退变表现。按ASD诊断标准,ASD的发生率为50.0%（30/60）,其中单纯上位邻近节段发生ASD 18例（30.0%）,单纯下位邻近节段发生ASD 8例（13.3%）,上、下邻近节段均发生ASD 4例（6.7%）。融合节段上位ASD发生率高于下位ASD发生率,两者差异有统计学意义（P〈0.05）。短节段融合组（单、双节段）ASD发生率55.5%（20/36）与长节段融合组（3~4节段）ASD发生率41.7%（10/24）相比,两者差异无统计学意义（P〉0.05）。结论颈椎前路融合术使ASD加速,ASD多发生于上位邻近节段,短节段融合患者与长节段融合患者ASD发生无明显差异。

Objective To investigate the incidence of adjacent segment degeneration（ ASD） after anterior cervical fusion（ ACF） and analyze its influence on the clinical outcomes. Methods From May 2008 to May 2013, a total of 60 patients with cervical spondylosis who underwent ACF were followed up clinically and radiologically, including single-segment fusion（ n = 10）, double-segment fusion（ n = 26）, triple-segment fusion（ n = 20） and foursegment fusion（ n = 4）. There were 32 males and 28 females, whose mean age was（ 57.25 ± 8.52） years（ range： 41-77 years）. The visual analogue scale（ VAS）, Japanese Orthopaedic Association scores（ JOAS） and neck disability index（ NDI） were used preoperatively and at the final follow-up. On the adjacent levels, the cervical lordosis, intervertebral height and osteophytes on the X-ray films were measured and the sagittal canal diameter and Miyazaki degenerative disc classification on the MRI were assessed. The incidence of ASD and its influence on the clinical outcomes were statistically analyzed during the follow-up. Results The patients were followed up for a mean period of（ 3.93 ± 1.76） years（ range： 2- 7 years）. The cervical lordosis at the final follow-up achieved significant improvement（ P〈0.05）. The intervertebral height below the fused levels was decreased significantly（ P〈0.05）, but no obvious changes were found above the fused levels（ P〉0.05）. The osteophytes were significantly enlarged on the adjacent levels（ P〈0.05）. The sagittal canal diameter was significantly decreased on the adjacent levels（ P〈0.05）. According to Miyazaki classification, severe degeneration was noticed in the upper and lower adjacent levels. Based on the diagnostic criteria, ASD developed in 30 of 60 patients（ 50.0%）. The morbidity of cephalic ASD was 30.0%（18 / 60）, tail side ASD was 13.3%（ 8 / 60） and both sides ASD was 6.7%（ 4 / 60）. The morbidity of cephalic ASD was higher than tail side ASD, and the differences were statistically significant（ P〈0.05）. According to the different fused levels, we divided the cases into short segments group（ 1 or 2 segments） and long segments group（ 3 or 4 segments）. The incidences of ASD in the 2 groups were 55.5%（ 20 / 36） and 41.7%（ 10 / 24）, and the differences weren＇t statistically significant（ P〉0.05）. Conclusions The ACF accelerates the occurrence of ASD. The morbidity of cephalic ASD is relatively higher. The length of fusion has no significant influence on the incidence of ASD.