Alan Nima, Vodovotz Lena, Muthiah Nallammai, Deng Hansen, Guha Daipayan, Agarwal Nitin, Ozpinar Alp, Mushlin Harry M, Puccio Lauren, Hamilton David K, Okonkwo David O, Kanter Adam S
1Department of Neurological Surgery, University of Pittsburgh Medical Center, Pittsburgh.
2University of Pittsburgh Medical Center, School of Medicine, Pittsburgh, Pennsylvania.
J Neurosurg Spine. 2022 May 20;37(5):663-669. doi: 10.3171/2022.4.SPINE2245. Print 2022 Nov 1.
Cage subsidence is a well-known phenomenon after lateral lumbar interbody fusion (LLIF), occurring in 10%-20% of cases. A 3D-printed porous titanium (pTi) cage has a stiffness that mimics the modulus of elasticity of native vertebrae, which reduces stress at the bone-hardware interface, lowering the risk of subsidence. In this study, the authors evaluated their institutional rate of subsidence and resultant reoperation in patients who underwent LLIF using a 3D-printed pTi interbody cage.
This is a retrospective case series of consecutive adult patients who underwent LLIF using pTi cages from 2018 to 2020. Demographic and clinical characteristics including age, sex, bone mineral density, smoking status, diabetes, steroid use, number of fusion levels, posterior instrumentation, and graft size were collected. The Marchi subsidence grade was determined at the time of last follow-up. Outcome measures of interest were subsidence and resultant reoperation. Univariable logistic regression analysis was performed to assess the extent to which clinical and operative characteristics were associated with Marchi grade I-III subsidence. Significance was assessed at p < 0.05.
Fifty-five patients (38 with degenerative disc disease and 17 with adult spinal deformity) were treated with 97 pTi interbody cages with a mean follow-up of 18 months. The mean age was 63.6 ± 10.1 years, 60% of patients were female, and 36% of patients had osteopenia or osteoporosis. Patients most commonly underwent single-level LLIF (58.2%). Sixteen patients (29.1%) had posterior instrumentation. The subsidence grade distribution was as follows: 89 (92%) grade 0, 5 (5%) grade I, 2 (2%) grade II, and 1 (1%) grade III. No patients who were active or prior smokers and no patients with posterior instrumentation experienced graft subsidence. No clinical or operative characteristics were significantly associated with graft subsidence. One patient (1.8%) required reoperation because of subsidence.
In this institutional case series, subsidence of pTi intervertebral cages after LLIF occurred in 8% of operated levels, 3% of which were grade II or III. Only 1 patient required reoperation. These reported rates are lower than those reported for polyetheretherketone implants. Further studies are necessary to compare the impact of these cage materials on subsidence after LLIF.
椎间融合器下沉是腰椎侧方椎间融合术（LLIF）后一种众所周知的现象，发生率为10%-20%。3D打印多孔钛（pTi）椎间融合器的刚度模拟天然椎体的弹性模量，可降低骨-植入物界面的应力，降低下沉风险。在本研究中，作者评估了使用3D打印pTi椎间融合器行LLIF患者的机构下沉率及由此导致的再次手术情况。
这是一项回顾性病例系列研究，纳入了2018年至2020年连续接受pTi椎间融合器LLIF手术的成年患者。收集患者的人口统计学和临床特征，包括年龄、性别、骨密度、吸烟状况、糖尿病、类固醇使用情况、融合节段数、后路内固定及移植物尺寸。在最后一次随访时确定马尔基下沉分级。关注的结局指标为下沉及由此导致的再次手术。进行单因素逻辑回归分析，以评估临床和手术特征与马尔基I-III级下沉的关联程度。以p<0.05评估显著性。
55例患者（38例患有退行性椎间盘疾病，17例患有成人脊柱畸形）接受了97个pTi椎间融合器治疗，平均随访18个月。平均年龄为63.6±10.1岁，60%的患者为女性，36%的患者患有骨质减少或骨质疏松。患者最常接受单节段LLIF（58.2%）。16例患者（29.1%）有后路内固定。下沉分级分布如下：0级89例（92%），I级5例（5%），II级2例（2%），III级1例（1%）。无现吸烟者或既往吸烟者以及无后路内固定的患者发生移植物下沉。无临床或手术特征与移植物下沉显著相关。1例患者（1.8%）因下沉需要再次手术。
在本机构病例系列中，LLIF术后pTi椎间融合器下沉发生率为8%的手术节段，其中3%为II级或III级。仅1例患者需要再次手术。这些报告的发生率低于聚醚醚酮植入物的报告发生率。有必要进一步研究比较这些椎间融合器材料对LLIF术后下沉的影响。
