颈椎椎间融合术后邻近节段病变的临床观察

CLINICAL OBSERVATION TO ADJACENT-SEGMENT DISEASE AFTER ANTERIOR CERVICAL DISCECTOMY AND FUSION

目的通过分析颈前路椎间盘切除、椎间融合术(anterior cervical discectomy and fusion,ACDF)术后长期随访患者的影像学资料和神经功能状态,探讨相邻节段病变的形成原因。方法1990年1月-2003年4月,实施ACDF1200余例,52例获得完整随访资料。男45例,女7例;年龄25～72岁,平均48.5岁。病程3个月～7年9个月,平均23.7个月。椎体融合节段:单间隙10例,双间隙38例,三间隙4例。术前均常规行颈椎正、侧位X线片、CT和MRI检查。采用Nurick评分,对比术后6周及随访结束时的神经功能状态;影像学检查:摄X线片、CT观察融合相邻椎体的滑动和椎体后缘骨赘增生情况,按照Goffin方法转化成半定量退变评分。采用Spearman相关系数法分析Nurick评分、椎体退变程度与患者手术时的年龄、椎体融合节段的关系,椎体退变程度与Nurick评分改变之间的关系。摄MRI观察椎体融合相邻节段及远离节段椎管矢状径的改变。结果52例获随访3～10年,平均6.9年。最后随访时影像学检查示45例(86.5%)患者出现退行性改变,8例(15.4%)自觉神经症状加重,2例(3.8%)接受二次手术治疗。术后6周Nurick评分(1.07±0.84)分,随访结束时(1.92±1.28)分,比较差异有统计学意义(P<0.05);Nurick评分的改变与患者手术时年龄(r=0.21,P>0.05)及椎体融合节段(r=0.30,P>0.05)无相关性。术后6周椎体退变评分(0.73±0.67)分,随访结束时(1.58±1.06)分,比较差异有统计学意义(P<0.01);椎体退变程度与患者手术时年龄(r=0.35,P>0.05)及椎体融合节段(r=0.38,P>0.05)无相关性。MRI显示融合相邻节段上位椎管矢状径减少,比较差异有统计学意义(P<0.01)。融合术后相邻椎体发生明显退行性改变,同时伴有神经症状改变,两者之间统计分析有相关性(r=0.41,P<0.05)。结论ACDF术后相邻节段病变由多种因素引发,椎间盘的自然退变、融合手术造成的生物力学性能的改变、手术对椎体前方韧带结构的破坏及植骨方式均是不可忽视的因素。

Objective To probe the etiopathogenisis of adjacent-segment disease by analyzing the imageology data and clinical neurological function in patients with anterior cervical discectomy and fusion （ACDF） harvested by long-term follow-up. Methods A retrospective study was performed on 52 patients who had undergone ACDF with perfect documents from January 1990 to April 2003. Of the patients, 45 were males and 7 were females with a mean age of 48.5 years （range from 25 to 72 years）. There was the fusion of 10 one,levels, 38 two-levels and 4 three-levels. The cervical anterior-posterior and lateral X-ray, CT and MRI examination were performed before the operation. Clinical neurological function was recorded by the Nurick score, and this score at 6 weeks after the operation was compared with the later follow-up. In the radiological examination, the motion of adjacent vertebrae and osteophyte formation were reviewed on X-ray and CT, and were converted to the semi-quantitative degeneration score according to the Goffin method. The correlation between Nurick score or degeneration score and the age at operation or fusion levels was compared by Spearman correlation coefficients. The cervical canal sizes of adjacent level and remote level on MRI were reviewed and compared with each other by t test. Results The follow-up period was 3 to 10 years, 6.9 years on average. There was difference in the Nurick score between the 6th week after operation （1.07± 0.84） and the later follow up （1.92± 1.28） by rank test （P 〈 0.05）. There was no correlation between the Nurick score change and the age at operation （r = 0.21, P 〉 0.05） or fused levels（r = 0.30, P 〉 0.05） by Spearman correlation coefficients. There was obvious difference in degeneration score between the 6th week after operation （0.73± 0.67） and the later follow up （1.58 ± 1.06）, （P 〈 0.01）. There was no correlation between the degeneration score change and the age at operation （r = 0.35, P 〉 0.05） or fusion levels （r = 0.38, P 〉 0.05） by Spearman correlation coefficients. The cervical canal size reductions were （1.7 ±1.1） mm at superior adjacent level, （1.2± 0.6） mm at inferior adjacent level and （0.30 ±0.68） mm at remote level. There was obvious difference between superior or inferior and remote level by t test （P 〈 0.01）. The adjacent level developed prominent degeneration together with nerve function change after the fusion operation and displayed correlation between degeneration and nerve function change（r = 0.41, P 〈 0.05）. Conclusion The adjacent-segment disease after interbody fusion is produced by multiple factors. The natural progression in adjacent disc, biomechanical natural change resulting from interbody fusion, destruction to ligament structure in front of cervical vertebrae by operation, and bone graft model are important factors not to be ignored.