Anatomical considerations for the extreme lateral (XLIF) approach

The purpose of this paper is to review the surgical technique, anatomical considerations and clinical outcomes of the extreme lateral interbody fusion (XLIF). With substantial technological innovation and refinement in surgical technique, the field of minimally invasive surgery in the lumbar spine has seen remarkable growth over the past 20 years. Disadvantages of the posterior and anterior approaches to the lumbar spine have led to the popularization of the lateral retroperitoneal transpsoas approach. The XLIF approach may be used throughout the lumbar spine (L1/2-L4/L5); however, the most notable concern with the XLIF and generally with the lateral transpsoas approach relates to the proximity of the approach, and thus consequent injury to the lumbar plexus and genitofemoral nerve. Several studies have reported the anatomy of the lumbar plexus and its relation to the far lateral approach. These studies are outlined in the body of the text. Because of its recent popularization, limited data exist regarding the clinical outcomes of the XLIF approach; however, preliminary reports look encouraging. Reported benefits include significant reductions in hospital stay, time to ambulation, postoperative narcotic use and postoperative visual analog scale scores. Several early reports have focused on the XLIF's ability to achieve correction of spinal deformity. Although mostly transient in nature, the XLIF approach carries risk for injury to the psoas muscle, the genitofemoral nerve and the nerves of the lumbar plexus. The lateral transpsoas approach is an excellent option and effective means for gaining access to the anterior lumbar spine over the conventional anterior transperitoneal approach. Long-term prospective clinical outcomes data are still required before comparisons to the more traditional approaches for lumbar fusion can be made.