Risk Factors for Subsidence Following Anterior Lumbar Interbody Fusion

Abstract

Study Design Retrospective cohort Objective Anterior lumbar interbody fusion (ALIF) may be complicated by subsidence, which can lead to significant morbidity including pain, disc space collapse, neural compression, segmental kyphosis, instability, and vertebral body fracture. This study sought to identify patient and procedural risk factors for subsidence in patients undergoing ALIF. Methods This study analyzed consecutive patients who underwent ALIF at a single institution with a minimum of 2 years follow-up. Patients were grouped as either Non-Subsidence (NS-ALIF) or Cage Subsidence (CS-ALIF) based on the final postoperative radiograph. Demographic variables, operative characteristics, and radiographic outcomes were evaluated to identify significant predictors on univariate and multivariate statistics. Results 144 patients (170 levels) were included with an average follow-up of 50.70 ± 28.44 months (4.23 years). The incidence of subsidence was 22.94% (39/170 levels). On univariate statistics, the CS-ALIF group was significantly older (P = .020), had higher BMI (P = .048), worse ASA (P = .001), higher prevalence of comorbid osteoporosis (P < .001), and a more anteriorly placed interbody device (P = .005). On multivariate analysis, anterior cage placement remained the only significant predictor (OR: 1.08, 95% CI: 1.03–1.14; P = .003). There was a significantly higher rate of subsequent adjacent segment surgery among the CS-ALIF group (P = .035). Conclusion Factors contributing to subsidence in ALIF included older age, higher BMI, severe ASA, and osteoporosis, while anterior cage placement remained the only independent predictor on multivariate analysis. Subsidence was associated with a higher rate of subsequent adjacent segment surgery. Surgical technique should optimize placement of the interbody cage and avoid overstuffing the disc space.

Three-Dimensional-Printed Titanium Versus Polyetheretherketone Cages for Lumbar Interbody Fusion: A Systematic Review of Comparative In Vitro, Animal, and Human Studies

“…20 Notably, several other demographic and surgery-related factors have been associated with the functional and clinical outcomes described in the studies included in this review. A study from Zavras et al 49 50 who found a positive association between obesity and increased rates of subsidence amongst patients who underwent ALIF. Regarding patient surgical characteristics, Peng et al 51 in a review of 32 patients undergoing ALIF, found that lower intraoperative pressure and complete removal of the intraoperative plate was associated with significantly reduced cage retropulsion.…”

“…Notably, several other demographic and surgery-related factors have been associated with the functional and clinical outcomes described in the studies included in this review. A study from Zavras et al [ 49 ] reviewing 144 patients who underwent anterior LIF (ALIF) found that older age, higher body mass index, patient frailty as quantified by the American Society of Anesthesiologists physical status classification grade, and a prior diagnosis of osteoporosis were each factors associated with increased subsidence. Similar results were described by Phan et al [ 50 ] who found a positive association between obesity and increased rates of subsidence amongst patients who underwent ALIF.…”

Cortical Endplate Bone Density Measured by Novel Phantomless Quantitative Computed Tomography May Predict Cage Subsidence more Conveniently and Accurately

“…The relationship between cage position and cage subsidence remains controversial. Zavras et al 32 showed that anterior cage placement is an independent risk factor for cage subsidence in ALIF. However, posterior cage placement is also a suggested risk factor for cage subsidence.…”

Development and validation of a risk prediction model for cage subsidence after instrumented posterior lumbar fusion based on machine learning: a retrospective observational cohort study

“…But long-term follow-up after surgery shows that the intervertebral height may be lost. This can lead to instrumentation failure, pseudoarthrosis, kyphotic deformity, adjacent-segment disease, and loss of foraminal height, any of which can lead to recurrent nerve root impingement and radicular pain (2)(3)(4). And studies have shown that cage subsidence is associated with postoperative revision surgery, and the rate of revision is significantly higher in patients with high-grade cage subsidence after fusion, there are some studies showed the rate of cage subsidence can reach 38% (5-7).…”

“…And studies have shown that cage subsidence is associated with postoperative revision surgery, and the rate of revision is significantly higher in patients with high-grade cage subsidence after fusion, there are some studies showed the rate of cage subsidence can reach 38% (5-7). Previous clinical studies have shown risk factors of cage subsidence (2)(3)(4)(5)8). But currently, it is rare to comprehensively use multiple relevant risk factors to predict and analyze the risk of subsidence.…”