Stand-alone versus supplemented ALIF: a systematic review and meta-analysis of pseudarthrosis and reoperation rates

Anterior lumbar interbody fusion (ALIF) is widely used for degenerative lumbar disc disease, offering restoration of disc height and sagittal alignment. However, pseudarthrosis remains a relevant complication, and the benefit of supplemental posterior fixation over stand-alone constructs is still debated. To compare the incidence of pseudarthrosis following stand-alone ALIF versus ALIF combined with posterior pedicle screw fixation. A systematic review and meta-analysis were conducted in accordance with PRISMA guidelines and registered in PROSPERO (CRD42024581358). PubMed/MEDLINE, Embase, Cochrane Library, and BVS were searched for studies published between 2013 and September 2024. Clinical studies including patients with degenerative lumbar disease undergoing ALIF with at least 12 months of follow-up were eligible. Study selection and data extraction were performed independently by two reviewers. Risk of bias was assessed using the Joanna Briggs Institute (JBI) tool for observational studies and Risk of Bias 2 (RoB 2) for randomized trials. Random-effects models were used to estimate pooled pseudarthrosis prevalence and clinical outcomes. Fourteen studies comprising 917 patients and over 1,000 operated levels were included. The pooled prevalence of pseudarthrosis was 8.17% (95% CI: 5.04-11.31), with substantial heterogeneity (I²=70.8%). Pseudarthrosis rates were numerically higher in stand-alone ALIF (8.95%; 95% CI: 4.54-13.37) compared with ALIF combined with posterior fixation (6.76%; 95% CI: 3.58-9.94), although the difference was not statistically significant (p = 0.429). Significant clinical improvement was observed, with a mean reduction of 4.16 points in VAS and a 24.46-point improvement in ODI. Meta-regression demonstrated no association between pseudarthrosis rates and clinical outcomes. Notably, stand-alone ALIF was associated with a significantly higher risk of reoperation for symptomatic pseudarthrosis (RR 6.8; 95% CI: 1.9-24.5; p < 0.01). ALIF provides substantial pain relief and functional improvement, with a relatively low overall rate of pseudarthrosis. Although stand-alone constructs showed a trend toward higher pseudarthrosis rates without statistical significance, they were associated with a markedly increased risk of reoperation. These findings suggest that, while fusion rates may appear comparable, supplemental posterior fixation may confer greater mechanical reliability and reduce clinically meaningful failure in selected patients.