经椎间孔单节段腰椎椎间融合术后融合器下沉的危险因素分析

Risk factors of cage subsidence after single level transforaminal lumbar interbody fusion

目的 探讨单节段经椎间孔腰椎椎间融合术（transforaminal lumbar interbody fusion,TLIF）术后融合器下沉对临床疗效的影响及其危险因素。方法 回顾性分析2011年5月至2014年5月采用聚醚醚酮（polyetheretherketone,PEEK）椎间融合器行TLIF手术的患者,于X线片上测量术前及术后各随访时点的手术节段椎间隙高度、节段性前凸角。根据手术节段椎间隙高度在随访期间的丢失值将患者分为融合器下沉组（≥2 mm）与融合器未下沉组（〈2 mm）。采用Oswestry功能障碍指数（Oswestry disability index,ODI）、腰腿痛视觉模拟评分（visual analogue scale,VAS）评价临床疗效。对可能影响融合器下沉的因素如年龄、性别、椎间隙高度、节段性前凸角等进行单因素与Logistic回归分析。结果 36例发生融合器下沉,发生率33.6%（36/107）。融合器下沉组36例,男15例,女21例,平均年龄（52.61±13.82）岁,平均随访（26.33±7.66）个月;融合器未下沉组71例,男28例,女43例,平均年龄（53.80±14.94）岁,平均随访（23.82±8.95）个月。两组患者性别、年龄、疾病病程、随访时间等基本资料的差异无统计学意义。融合器下沉组下沉2.02~5.53 mm,平均（2.79±0.78） mm。单因素分析结果为术前椎间隙高度、术后椎间隙高度、术后节段性前凸角与融合器下沉有关;Logistic回归分析结果为术后椎间隙高度为融合器下沉的危险因素[OR=1.864,95%CI为（1.207,2.879） mm]。术前及术后各随访时点融合器下沉组与融合器未下沉组VAS评分及ODI的差异均无统计学意义。结论 融合器下沉受术前手术节段椎间隙高度、术后节段椎间隙高度、术后节段性前凸角的影响,其中术后节段椎间隙高度是独立危险因素,椎间隙过度撑开可增加融合器下沉风险。

Objective To investigate the relationship between clinical efficacy and cage subsidence, and to identify the risk factors of cage subsidence after transforaminal lumbar interbody fusion （TLIF） in treating single level lumbar disc herniation and lumbar spondylolisthesis. Methods According to the inclusion/exclusion criteria, a series of 107 patients who underwent TLIF with polyetheretherketone （PEEK） cage in our department were evaluated retrospectively between May 2011 and May 2014. Intervertebral space height and segmental angle were measured on the preoperative and postoperative iconography according to the metrical software. All patients were divided into cage subsidence group （cage subsidence ≥ 2 mm） and cage non-subsidence group （cage subsidence〈2 mm） based on the threshold value of intervertebral space height via X-ray. The Oswestry disability index （ODI） and visual analogue scale （VAS） was used to evaluate the clinical efficacy. Univariate analysis and logistic regression analysis were performed to identify the potential risk factors. Results Of all 107 patients, thirty-six patients （15 males and 21 females） aged 52.61±13.82 years were divided into in the cage subsidence group with an average follow-up duration 26.33±7.66 months, seventy-one patients aged 53.80±14.94 years, 28 males and 43 females in the cage non-subsidence group, were followed-up for 23.82±8.95 months. There was no significant difference between cage subsidence group and cage non-subsidence group in gender, age, course of disease and time of follow-up （P〉0.05）. The average 2.79±0.78 mm （range 2.02-5.53 mm） subsidence was observed in cage subsidence group. The preoperative intervertebral space height, postoperative intervertebral space height, postoperative segmental angle were related to cage subsidence by univariate analysis （P〈0.05）. Postoperative intervertebral space height [OR=1.864,95%CI（1.207, 2.879） mm] was the risk factor of cage subsidence by logistic regression （P〈0.05）. There was no significant difference between cage subsidence group and cage non-subsidence group in ODI and VAS （P〉0.05）. Conclusion Cage subsidence is affected by the preoperative intervertebral space height, postoperative intervertebral space height, and postoperative segmental angle. Postoperative intervertebral space height is the independent risk factor of cage subsidence. Over distraction of intervertebral space height could increase the risk of cage subsidence.