Comparison of anterolateral versus posterior lumbar fusion techniques in obese patients: a systematic review and meta-analysis.

INTRODUCTION: Obesity increases the risk of developing lumbar spine disease and the need for subsequent surgical intervention. However, there is no consensus regarding the safety profiles and quality-of-life (QoL) outcomes of different lumbar interbody fusion (LIF) approaches in obese patients. This review compares perioperative, postoperative and QoL outcomes between anterolateral (ALA) and posterior approaches (PA) in obese patients undergoing elective LIF. METHODS: PubMed, Scopus, and Cochrane databases were searched for studies comparing ALA and PA in adult obese patients undergoing elective LIF. Pooled risk ratios (RRs) and mean differences (MDs) with 95% confidence intervals (CIs) were calculated for binary and continuous outcomes, respectively. Heterogeneity was assessed using I2 statistics, and analyses were performed using R (Version 4.5.2). RESULTS: Eight observational studies comprising 26,030 obese patients undergoing LIF were included, of whom 10,230 (39.30%) underwent an ALA. Risk of bleeding requiring transfusion was significantly lower in the ALA group (8.89% vs. 14.09%; RR = 0.88; 95% CI = 0.81, 0.95; p = 0.002; I2 = 0%), as was the risk of unplanned revision surgery (2.46% vs. 3.56%; RR = 0.70; 95% CI = 0.55, 0.88; p = 0.002; I2 = 0%). No significant differences were observed between groups in mean back pain Visual Analog Scale (VAS-Back) scores at 3 months (MD = 1.6 cm; 95% CI = -11.79, 14.99; p = 0.37; I2 = 90.3%) or 6 months (MD = 0.45 cm; 95% CI = -10.56, 11.46; p = 0.70; I2 = 83.9%). Similarly, mean Oswestry Disability Index (ODI) scores did not differ at 3 months (MD = 3.82%; 95% CI = -169.79, 169.42; p = 0.82; I2 = 97.3%) or 6 months (MD = 2.51%; 95% CI = -96.86%, 101.88%; p = 0.80; I2 = 91.8%). However, ALA were associated with significantly higher mean VAS-Back (MD = 1.11 cm; 95% CI = 0.52, 1.70; p < 0.01; I2 = 0%) and ODI scores (MD = 8.69%; 95% CI = 5.36, 12.02; p < 0.01; I2 = 0%) at 12 months. CONCLUSION: For obese patients undergoing elective LIF, ALA reduced the risk of bleeding requiring transfusion and unplanned revision surgery compared to PA. No significant differences in mean VAS-Back or ODI scores were observed at 3 or 6 months. Nevertheless, ALA were associated with higher mean VAS-Back and ODI scores at 12 months. Despite reaching statistical significance, these differences did not attain the minimal clinically important difference (MCID) for either outcome.