IN WHICH PATIENTS IS IT POSSIBLE TO PERFORM STANDALONE LATERAL LUMBAR INTERBODY FUSION WITHOUT CAGE SUBSIDENCE?

ABSTRACT Objective: To identify the factors related to the non-occurrence of cage subsidence in standalone lateral lumbar interbody fusion procedures. Methods: Case-control study of single level standalone lateral lumbar interbody fusion (LLIF) including 86 cases. Patients without cage subsidence composed the control group (C), while those in the subsidence group (S) developed cage subsidence. Preoperative data were examined to create a risk score based on correlation factors with S group. The proven risk factors were part of an evaluation score. Results: Of the 86 cases included, 72 were in group C and 14 in group S. The following risk factors were more prevalent in group S compared to C group: spondylolisthesis (93% vs 18%; p<0.001); scoliosis (31% vs 12%; p=0.033); women (79% vs 38%; p=0.007); older patients (average 57.0 vs 68.4 years; p=0.001). These risk factors were used in a score (0-4) to evaluate the risk in each case. The patients with higher risk scores had greater subsidence (p<0.001). Scores ≥2 were predictive of subsidence with 92% sensitivity and 72% specificity. Conclusions: It was possible to correlate the degree of subsidence in standalone LLIF procedures using demographic (age and gender) and pathological (spondylolisthesis and scoliosis) data. With a score based on risk factors and considering any score <2, the probability of non-occurrence of subsidence following standalone LLIF (negative predictive value) was 98%.

摘要
研究目的：明确单纯侧路腰椎椎间融合术（standalone lateral lumbar interbody fusion, LLIF）中椎间融合器沉降未发生的相关影响因素。
研究方法：本研究为病例对照研究，纳入86例单节段单纯LLIF手术病例。将未发生椎间融合器沉降的患者设为对照组（C组），发生沉降者纳入沉降组（S组）。基于与S组相关的危险因素分析患者术前资料，构建风险评分模型，经证实的危险因素被纳入该评分体系。
研究结果：纳入的86例病例中，72例归入C组，14例归入S组。与C组相比，S组中以下危险因素的占比显著更高：腰椎滑脱（93% vs 18%；p<0.001）、脊柱侧凸（31% vs 12%；p=0.033）、女性患者（79% vs 38%；p=0.007）以及高龄患者（平均年龄57.0岁 vs 68.4岁；p=0.001）。基于上述危险因素构建0~4分的风险评分模型，用于评估每例患者的手术风险。风险评分更高的患者，其椎间融合器沉降发生率显著更高（p<0.001）。当评分≥2分时，预测沉降发生的灵敏度为92%，特异度为72%。
研究结论：本研究证实，可通过人口统计学资料（年龄与性别）及病理学资料（腰椎滑脱与脊柱侧凸），关联单纯LLIF术中椎间融合器沉降的发生程度。基于上述危险因素构建的评分模型，当评分<2分时，单纯LLIF术后未发生沉降的阴性预测值为98%。