Lateral Lumbar Interbody Fusion (LlLF), Anatomical View

Description

Lumbar vertebral bodies are presented in lateral profile with an interbody cage seated within the intervertebral disc space, bridging the adjacent endplates to restore disc height. The device occupies the anterior to middle portion of the disc space, with the remaining annulus fibrosus and the anterior longitudinal ligament forming the ventral boundary and the posterior longitudinal ligament lying posterior to the vertebral bodies. Posterior elements (pedicles, laminae, and spinous processes) sit dorsal to the cage, while the transverse processes mark the lateral margin of the motion segment. A single level is emphasized. Lateral lumbar interbody fusion (LLIF) is commonly selected for degenerative disc disease, low grade spondylolisthesis, and adult degenerative scoliosis when surgeons want indirect foraminal decompression by re-expanding disc height and tensioning the annulus rather than directly unroofing the canal. The lateral trajectory also brings regional hazards into focus: the psoas major overlies the lateral disc, the lumbar plexus courses within it (with the femoral nerve typically more anterior at L4 to L5), and the sympathetic chain and segmental vessels occupy the anterolateral vertebral body. Seeing the cage centered between endplates in a true lateral anatomical relationship helps explain subsidence risk when endplate preparation violates subchondral bone, and it clarifies why cage position influences segmental lordosis and foraminal area. Spine surgery atlases and device manuals can pair this illustration with step descriptions of a retroperitoneal transpsoas approach and implant sizing. It also fits orthopedic and neurosurgical teaching on interbody fusion biomechanics, sagittal alignment, and approach-related neurologic complications for residents and fellows. Anatomical accuracy verified by SciePro's Medical Advisory Board.