Extreme lateral interbody fusion (XLIF), also known as direct lateral interbody fusion (DLIF), is a minimally invasive surgical technique that approaches the lumbar spine through the retroperitoneal space and traverses the psoas muscle to access the lateral disc space. Compared with anterior lumbar interbody fusion (ALIF), the lateral approach avoids the great vessels and peritoneal cavity, while compared with posterior approaches it preserves posterior musculature, supraspinous and interspinous ligaments, and avoids dural retraction. A wide PEEK or titanium cage placed laterally restores disc height, indirectly decompresses the foramen and central canal, and provides a strong foundation for fusion across the entire endplate apophyseal ring.
Indications include adult degenerative scoliosis, lumbar spondylolisthesis (grade I-II), discogenic low back pain, lateral recess and foraminal stenosis with disc collapse, adjacent segment disease after prior fusion, and select cases of post-traumatic instability. Levels accessible from L1 to L5 allow multilevel reconstruction; L5-S1 is generally inaccessible due to iliac crest. Advanced applications include hyperlordotic cages for sagittal correction, anterior column realignment as an alternative or adjunct to PSO for adult deformity, and combined posterior pedicle screw stabilization for higher-grade deformity.
Surgical technique includes lateral decubitus positioning, neurophysiologic monitoring with directional EMG to identify lumbar plexus position within the psoas, sequential dilation through the psoas, retraction system placement, discectomy, endplate preparation, and implant deployment. Postoperative care emphasizes early mobilization, pain management, and assessment for psoas-related symptoms. Complications include transient hip flexor weakness from psoas injury (10-30%), thigh paresthesias from genitofemoral nerve traction (10-25%), lumbar plexus injury (1-5%) including femoral nerve involvement, vascular injury (less than 1%), retroperitoneal hematoma, ileus, cage subsidence in osteoporotic bone, and pseudarthrosis. Outcomes show fusion rates of 90-95%, significant improvements in disability and pain, and reduced blood loss and hospital stay compared with traditional posterior interbody techniques.