A systematic review of anterior lumbar interbody fusion (ALIF) versus posterior lumbar interbody fusion (PLIF), transforaminal lumbar interbody fusion (TLIF), posterolateral lumbar fusion (PLF)

Elective lumbar fusion for degenerative conditions has risen, particularly for spondylolisthesis. Multiple fusion options (ALIF, PLIF, TLIF, PLF) exist without consensus on an optimal approach for DDD or spondylolisthesis. ALIF offers potential advantages (restoration of disc height/lordosis, larger graft footprint, indirect decompression, avoidance of posterior muscle/ligament injury) but has unique risks (vascular/visceral/neurologic injury). Stand-alone ALIF may obviate posterior instrumentation, potentially reducing operative time, blood loss, and recovery burden. Prior studies often pooled heterogeneous populations and techniques. This review evaluates whether stand-alone ALIF yields superior perioperative outcomes, fusion rates, and patient-reported outcomes versus posterior techniques in adults with DDD and spondylolisthesis.

Design: Systematic review and meta-analysis registered in PROSPERO. Eligibility: Adults with back/leg pain due to DDD or spondylolisthesis who failed ≥6 weeks of nonoperative management undergoing stand-alone ALIF versus posterior fusion (PLIF, TLIF, PLF). Included designs: randomized trials, cohort studies, and case series. Exclusions: uninstrumented posterior fusion, long constructs, kyphosis/scoliosis, prior circumferential (360°) fusions, non-comparable approaches. Search: MEDLINE, EMBASE, Cochrane Register of Trials (inception to Feb 2022), no language restriction; reference list checks; grey literature via OpenGrey and ClinicalTrials.gov. Screening: Three reviewers independently screened titles/abstracts; full texts assessed with consensus resolution. Data extraction and quality: Two reviewers extracted data; risk of bias assessed with Cochrane Back Review Group criteria. Statistical analysis: RevMan 5.4.1; random-effects models; relative risk (RR) with 95% CI for dichotomous outcomes; mean difference (MD) with 95% CI for continuous outcomes. For studies reporting medians/IQR or ranges, means/SDs were estimated using Hozo, Wan, and Walter methods. Heterogeneity evaluated with chi-square and I2 statistics. Study profile: 21 studies (3,686 patients) from 8 countries; 1 RCT, 20 observational. Primary diagnoses: DDD and spondylolisthesis. Follow-up commonly 1–2 years.

Overall: 21 studies (n=3,686); 1 RCT, remaining observational. Countries: USA (10), Germany (2), China (2), Japan (2), South Korea (2), Denmark, Italy, UK. Main comparisons: ALIF vs TLIF (8 studies), ALIF vs PLIF (4), ALIF vs PLF (6), and some multi-arm.

• Operative metrics • ALIF vs TLIF: Surgical time significantly shorter with ALIF; pooled estimate reported as MD −48.16 min (n=969; CI −70.86 to −25.45). Blood loss lower with ALIF (n=480; MD −192.65 ml; CI −256.41 to −128.90; I2=94%). Length of stay shorter with ALIF (n=883; MD −0.71 days; CI −1.42 to −0.00; I2=76%). • ALIF vs PLIF: Surgical time shorter with ALIF (n=146; MD −41.62 min; CI −61.87 to −21.37). Blood loss lower with ALIF (n=146; MD −186.61 ml; CI −355.18 to −18.04). • ALIF vs PLF: Surgical time trend favoring ALIF but not significant (n=536; MD −40.98 min; CI −86.47 to 4.52; p=0.08; I2=94%). Blood loss not significantly different (2 studies, n=77; MD −261.44 ml; CI −566.56 to 43.60). Length of stay not significantly different (4 studies, n=592; MD 0.90 days; CI −1.47 to 3.27).
• Fusion rate • No significant differences between ALIF and TLIF at 1 year (2 studies, n=111; RR 1.00; CI 0.95 to 1.05) or 2 years (no significant difference). No significant differences between ALIF and PLF (6 studies; n=219; RR 1.02; CI 0.94 to 1.10). Overall, fusion rates similar across approaches.
• Patient-reported outcomes • ALIF vs TLIF: ODI at 1 year (4 studies, n=1217; MD −2.63; CI −6.76 to 1.50) and 2 years (3 studies, n=1507; MD −0.02; CI −1.90 to 1.86) not significantly different. SF-36 PCS 1 year (n=906; MD 0.96; CI −0.97 to 2.89) and 2 years (2 studies, n=1425; MD −0.07; CI −2.64 to 2.51) not different. SF-36 MCS 1 year (n=906; MD 2.15; CI −0.18 to 4.48; p=0.07) and 2 years (2 studies, n=1425; MD 0.02; CI −1.96 to 2.01) not different. VAS back and leg pain generally not significantly different. • ALIF vs PLIF: ODI up to 18 months (n=58; MD 5.10; CI −0.51 to 10.71) and 2 years (n=74; MD 2.40; CI −6.40 to 11.20) not significantly different. Modified Prolo scale (n=28; RR 2.08; CI 0.88 to 4.91), no difference. • ALIF vs PLF: VAS back pain favored ALIF at 1 year (n=21; MD −1.00; CI −1.47 to −0.53) and 2 years (2 studies, n=67; MD −1.39; CI −1.67 to −1.11). VAS leg pain at 2 years favored PLF (n=46; MD 0.50; CI 0.12 to 0.88). ODI at 1 year not different (2 studies, n=265; MD −1.17; CI −7.76 to 5.42), but at 2 years favored ALIF (2 studies, n=67; MD −7.59; CI −13.33 to −1.85; I2=70%). JOAS: low back pain favored ALIF at 1 year (n=21; MD −0.50; CI −0.78 to −0.22) and 2 years (n=67; MD −0.36; CI −0.65 to −0.07); leg pain at 2 years not different (n=46; MD −0.20; CI −0.61 to 0.21).
• Adverse events • Across comparisons (ALIF vs TLIF/PLIF/PLF), serious and minor adverse event rates, need for further surgery, readmissions, DVT, hematoma, ileus, dural tears, blood transfusions, and adjacent segment degeneration showed no significant differences; overall rates were low.

The review addresses the clinical question of whether stand-alone ALIF provides advantages over posterior lumbar fusion techniques for DDD and spondylolisthesis. Findings indicate ALIF yields shorter operative time and less intraoperative blood loss than TLIF/PLIF, with shorter hospital stays than TLIF, suggesting perioperative efficiency and potential cost benefits. Fusion rates were similar across approaches, indicating that the choice of approach may be guided by perioperative profiles and patient-specific factors rather than differences in fusion success. PROMs were largely equivalent between ALIF and PLIF/TLIF, while ALIF outperformed PLF on several back pain and disability measures at longer-term follow-up, though leg pain outcomes at 2 years favored PLF. Adverse event profiles were comparable, though minor events may be underreported. Overall, stand-alone ALIF appears advantageous in perioperative metrics without compromising fusion or global patient-reported outcomes, with some PROM advantages over PLF.

Stand-alone ALIF is associated with shorter operative time and less blood loss than PLIF/TLIF and a reduced length of stay compared with TLIF. Fusion rates and most PROMs are comparable between ALIF and PLIF/TLIF. Compared with PLF, ALIF demonstrates better back pain and disability outcomes at certain time points, while leg pain at 2 years may favor PLF. Adverse event rates are similar across approaches. Future research should include well-designed randomized and prospective studies adhering to CONSORT and STROBE guidelines, with standardized reporting of PROMs, adverse events, fusion assessment methods, and longer-term follow-up to clarify effects on outcomes and adjacent segment disease.

Most included studies were non-randomized, with potential selection and allocation biases. Baseline prognostic factors were often unreported or imbalanced (e.g., age, PROMs, bone mineral density, spondylolisthesis grade, smoking). Surgeons were not blinded, and approach selection was frequently surgeon- or pathology-dependent, introducing confounding. Heterogeneity in surgical techniques (device types, graft materials, fixation methods, open vs minimally invasive approaches) and limited detail impeded subgroup analyses. PROM data were limited and short-term (1–2 years), with variability in measurement and reporting. Fusion assessment methods and timing lacked standardization. Minor adverse events may be underreported, potentially underestimating complication rates.