Abstract
BACKGROUND: Extraforaminal lumbar interbody fusion (ELIF) accesses the disc through a posterolateral extraforaminal corridor that preserves the posterior ligamentous complex and avoids abdominal exposure. The objective of this systematic review is to synthesize the clinical outcomes, fusion rates, complications, and surgical indications for ELIF. METHODS: PRISMA 2020-conformant review registered in PROSPERO (ID: 1111090). Eligible studies reported clinical or radiographic outcomes of ELIF performed via the posterolateral extraforaminal approach. Extracted variables included indications, operative time, patient-reported outcomes, fusion, and complications. Risk of bias was assessed with the Newcastle-Ottawa Scale (NOS). RESULTS: Thirteen retrospective studies (n=518) met inclusion. The quality of studies included was generally fair, as graded by Newcastle-Ottawa Scale (NOS). The most common indication was degenerative disc disease. Mean operative time was 168.7 minutes. Fusion by technique: open pooled mean 98%, minimally invasive pooled mean 84%, and endoscopic 100% in a single series. Pooled VAS back improved as follows: open 6.27 to 2.80 (Δ 3.47; mean follow-up 12.8 months), minimally invasive 8.16 to 3.52 (Δ 4.64; 18.8 months), endoscopic 6.49 to 1.66 (Δ 4.83; 13.2 months). Pooled VAS leg improved: open 6.66 to 2.35 (Δ 4.31, 13.3 months), minimally invasive 8.66 to 2.17 (Δ 6.49; 15.5 months), endoscopic 6.60 to 1.50 (Δ 5.10; 14.2 months). Pooled Oswestry disability index (ODI) improved: open 60.17 to 26.25 (Δ 33.92; 9.5 months), minimally invasive 56.02 to 21.46 (Δ 34.56; 18.8 months), endoscopic 34.59 to 12.19 (Δ 22.40; 13.2 months). Transient radiculopathy was reported at 9.5% and dural tear at 0.5%. CONCLUSIONS: As the first systematic review on ELIF, findings indicate it is a safe, effective alternative for lumbar fusion in select patients. Success necessitates favorable extraforaminal anatomy and intraoperative nerve monitoring to minimize complications. Future prospective trials are essential to validate these outcomes and standardize patient selection criteria.