腰椎后路椎间融合术后融合器后移的影响因素及再手术策略

Factors of cage migration after posterior lumbar interbody fusion and strategies for reoperation

目的分析腰椎后路椎间融合术后融合器(cage)后移的主要影响因素及再手术策略。方法回顾性分析自2017-01—2021-12行腰椎后路减压椎弓根钉棒内固定椎间植骨融合术治疗的1214例退行性腰椎疾病患者,术后第1次侧位X线片和术后随访比较时cage后缘金属标记物向后移位≥2 mm的患者标记为cage移位组,再根据随机原则抽取100例无cage后移的患者标记为非移位组,比较两组患者基本资料、手术前后平均椎间隙高度及腰椎前凸角、融合前后椎间盘高度差、螺钉松动情况、cage置入深度、融合节段数量。结果所有患者均获得随访,随访时间6~18个月,平均11.3个月。21例出现术后cage后移,其中4例需行再手术,再手术节段分别为:L3、41例,L4、52例,L5S11例,其中1例是第1次翻修术后再次cage后移,被迫行二次翻修手术。cage后移组(n=21)手术前后平均椎间隙高度均较非移位组(n=100)高,差异有统计学意义(P<0.05),说明选择相对较小的cage是后移的影响因素。此外,骨质疏松、置入深度不足、螺钉松动、梨形椎间隙、长节段固定后发生cage后移的概率也明显更高,差异均有统计学意义(P<0.05)。结论腰椎后路椎间融合术后cage移位是多种因素造成的结果,骨质疏松症、cage相对较小、置入深度不足、“梨形”椎间隙、长节段固定及内固定松动是融合术后cage移位的主要危险因素。翻修手术应找到cage后移的主要因素而制定个性化的再手术方案,无附加损伤地取出cage、椎间及钉道的重新制备、恢复腰椎前凸角是再手术成功的关键因素。

Objective To analyze the main influencing factors of cage migration after posterior lumbar interbody fusion and the strategies for reoperation.Methods A retrospective analysis was conducted on 1214 patients with degenerative lumbar dis-eases who underwent posterior lumbar decompression pedicle screw fixation interbody fusion surgery from January 2017 to De-cember 2021.Patients with backward displacement of the metal marker at the posterior margin of cage≥2 mm at the first postop-erative lateral X-ray and postoperative follow-up were labeled as cage displacement group,and 100 patients without cage migra-tion were randomly selected as the non-migration group.The basic information of the two groups of patients,the average inter-vertebral height before and after surgery,lumbar lordosis angle,difference in intervertebral disc height before and after fusion,screw loosening,cage insertion depth,and number of fused segments were compared.Results All patients were followed up for an average of 11.3 months,ranging from 6 to 18 months.Postoperative cage migration occurred in 21 cases,of which 4 cases required reoperation.The segments for reoperation were L3、4 in 1 case,L4、5 in 2 cases,and L5S1 in 1 case.One case experienced cage migration again after the first revision surgery,necessitating a second revision surgery.The mean intervertebral height be-fore and after surgery in the cage migration group(n=21)was higher than that in the non-migration group(n=100),with statisti-cally significant differences(P<0.05),indicating that choosing a relatively smaller cage is a factor influencing migration.In addi-tion,osteoporosis,insufficient insertion depth,screw loosening,pear-shaped intervertebral space,and cage migration after longsegment fixation also had significantly higher probabilities,with statistically significant differences(P<0.05).Conclusion cage migration after posterior lumbar interbody fusion surgery is the result of multiple factors.Osteoporosis,relatively smaller cage,insufficient insertion depth,“pear-shaped”intervertebral space,long-segment fixation,and loosening of internal fixation are the main risk factors for cage migration after fusion.Revision surgery should identify the main factors causing cage migration and develop individualized reoperation plans.The key factors for successful revision surgery include the removal of the cage without additional injury,re-preparation of the intervertebral space and pedicle,and restoration of lumbar lordosis angle.