腰椎融合术前相邻节段退变对术后中长期临床疗效的影响

Effect of pre-existing adjacent segment degeneration on medium and long term prognosis after lumbar fusion

目的:分析术前相邻节段退变(adjacent segment degeneration,ASD)对腰椎融合术后中长期预后的影响,比较术前邻近节段椎管狭窄的程度与椎间盘退变的程度对相邻节段病变(adjacent segment disease,ASDis)的影响。方法:回顾性研究2002年1月～2010年12月在我院因腰椎管狭窄症行后路减压、椎弓根螺钉固定和植骨融合术的59例患者(男27例,女32例),年龄38～80岁,平均63.0±9.6岁。所有患者均融合至S1,平均随访时间为80.7±7.4个月(72～96个月)。收集患者体重指数(BMI)、术前及末次随访时Oswestry功能障碍指数(ODI)、日本骨科协会(JOA)评分、视觉模拟评分(VAS)。影像学资料包括术前及末次随访时的腰椎MRI、腰椎正侧伸屈位X线。用MRI与X线片判定术后ASD情况,观察指标包括相邻节段椎间盘Pfirrman分级、椎管狭窄程度、节段不稳定、椎间隙高度、椎体前后缘骨赘等。应用椎管内脑脊液闭塞程度与Pfirrman分级评价术前邻近节段退变的程度。若在随访期内出现下肢神经症状加重或腰痛加重,结合影像学表现诊断为ASDis。以末次随访是否出现ASDis分组,比较组间影响因素差异。应用Logistic回归分析,分析影响末次随访时ASDis的危险因素。结果:末次随访时共38例患者(38/59,64.4%)出现影像学上ASD,其中9例患者(9/59,15.3%)诊断为ASDis。共40例患者(40/59,67.8%)术前相邻节段椎管无明显狭窄,评为0级,其中2例末次随访时出现ASDis;共19例患者(19/59,32.2%)术前相邻节段椎管存在轻度狭窄,评为1级,其中7例末次随访时出现ASDis。术前不同相邻节段椎管形态的患者ASDis发生率存在显著差异(P=0.003)。Logistic回归分析表明,术前相邻节段椎管的狭窄程度与融合节段长短为影响ASDis的危险因素。结论:对于术前相邻节段退变程度的评估,应重视相邻节段椎管狭窄程度的评估,椎管狭窄和长节段固定融合显著增加术后中长期相邻节段病变的风险。

Objectives: To analyze the effect of pre-existing adjacent segment degeneration(ASD) on the long-term prognosis after lumbar fusion, and to compare the effect of canal stenosis and the degree of intervertebral disc degeneration on adjacent segment disease(ASDis). Methods: By retrieving the medical records from January 2002 to December 2010 in our hospital with the inclusion criteria of lumbosacral fusion and at least five years follow-up, 59 patients (27 males, 32 females;mean age, 63.0±9.6 years) were enrolled, with 80.7±7.4 months(72-96 months) follow-up. Preoperative and final follow-up radiographs and MRI images were evaluated. BMI, preoperative and final follow-up ODI, JOA, VAS scores were collected. Final follow-up adjacent segment degeneration was evaluated on MRI and radiographs. Observation indexes included Pfirrman′s grades of adjacent discs, spinal stenosis, instability of segments, height of intervertebral space, osteophytes of anterior and posterior margins of vertebral bodies. The degree of pre-existing adjacent segment degeneration was evaluated by obliteration of anterior cerebrospinal fluid space and Pfirrman′s grades. If neurological symptoms of lower extremities or low back pain were aggravated during the follow-up period, the adjacent segment disease(ASDis) were diagnosed. Influencing factors were compared between ASDis group and no ASDis group. Logistic regression analysis was used to analyze the risk factors of adjacent segment disease in final follow-up. Results: In the final follow-up, ASD were found in 38 cases(38/59, 64.4%), and 9 patients(9/59, 15.3%) were diagnosed ASDis. Forty patients(40/59, 67.8%) who had no obvious pre-existing stenosis at adjacent segments were rated as grade 0, 2 patients had ASDis at final follow-up. Nineteen patients(19/59, 32.2%) had mild pre-existing stenosis at adjacent segments, which were rated as grade 1, 7 patients had ASDis at final follow-up. The incidence of ASDis was significantly different between the two groups(P=0.003). Logistic regression analysis showed that the degree of pre-existing canal stenosis and length of fusion segments were risk factors for adjacent segment lesions. Conclusions: Compared with the degeneration of intervertebral disc, more attention should be paid to the evaluation of the degree of adjacent spinal canal stenosis, especially for the presence of mild spinal canal stenosis, which will significantly increase the risk of long-term adjacent segment disease.