Anatomical Study of the Extreme Lateral Transpsoas Lumbar Interbody Fusion with Application to Minimizing Injury to the Kidney.

Objective Since the extreme lateral lumbar interbody fusion procedure was first reported by Ozgur in 2006, a large number of clinical studies have been published. Anatomical studies which explore methods to avoid visceral structures, such as the kidney, with this approach have not been examined in detail. We dissected the retroperitoneal space to analyze how the extreme lateral transpsoas approach to the lumbar spine could damage the kidney and related structures. Methods Eight sides from four fresh Caucasian cadavers were used for this study. The latissimus dorsi muscle and the thoracolumbar fascia were dissected to open the retroperitoneum. The fat tissue was removed. Steel wires were then put into the intervertebral disc spaces. Finally, the closest distance between kidney and wires on each interdiscal space was measured. Results The closest distance from the wire in the interdiscal space on L1/2, L2/3 and L3/4 to the kidney ranged from 13.2 mm to 32.9 mm, 20.0 mm to 27.7 mm, and 20.5 mm to 46.6 mm, respectively. The distance from the kidney to the interdiscal space at L4/5 was too great to be considered applicable to this study. Conclusions The results of this study might help surgeons better recognize the proximity of the kidney and avoid injury to it during the extreme lateral transpsoas approach to the lumbar spine.