Extreme lateral interbody fusion (XLIF) was popularized by Pimenta in the early 2000s as a minimally invasive alternative to anterior and posterior lumbar interbody fusion approaches. The technique utilizes a lateral retroperitoneal approach to the lumbar spine via a small flank incision (typically 4-5 cm), blunt retroperitoneal dissection, transpsoas corridor through the psoas muscle (with electromyographic monitoring to avoid lumbar plexus injury), and use of an expandable tubular retractor to access the disc space directly from the lateral side.
Indications include single or multi-level degenerative disc disease, low-grade spondylolisthesis, adult degenerative scoliosis (powerful for coronal correction), recurrent disc herniation requiring fusion, post-laminectomy syndrome, and adjacent segment disease above prior fusion. Levels accessible are L1-L2, L2-L3, L3-L4, and L4-L5 (latter is technically more challenging due to iliac crest position and potential lumbar plexus injury risk); L5-S1 is generally not accessible via XLIF (requires ALIF or oblique lumbar interbody fusion — OLIF). Advantages over PLIF/TLIF include preservation of posterior tension band and bone, ability to use much wider cages providing better load distribution and indirect decompression, less blood loss, and faster recovery; advantages over ALIF include avoidance of major vessel and viscera, no risk of retrograde ejaculation in males, and feasibility in patients with prior abdominal surgery.
Surgical technique includes lateral decubitus positioning with breaks at iliac crest, fluoroscopic localization, small flank incision and blunt retroperitoneal dissection, transpsoas corridor with continuous neuromonitoring (free-running and triggered EMG), discectomy with endplate preparation, placement of large interbody cage (often 18-22 mm wide, sized to span both apophyseal rings) with autograft or biologic, and supplemental posterior or lateral fixation in most cases (percutaneous pedicle screws, lateral plate). Outcomes are favorable with 85-95% fusion rates, significant pain reduction, and effective indirect decompression. Complications include lumbar plexus injury (transient hip flexion weakness in 20-30%, persistent in <5%), thigh pain/numbness (common but usually transient), bowel injury (rare), vascular injury, and pseudarthrosis.