Oblique lumbar interbody fusion at the L5-S1 segment via an approach between the psoas muscle and the great vessels: technique note and case presentations.

Study Design: Technique note. Objectives: To describe our modified oblique lumbar interbody fusion (OLIF) technique in the reconstruction of the L5-S1 segment. Summary: of Background Data: Recently, OLIF has been generally recognized as an effective procedure in the treatment of various spinal pathologies at L2-L5 segments. However, the usage of OLIF at the L5-S1 segment doesn’t have gained widespread acceptance in spine community. Some authors still concern about the feasibility of OLIF used in lumbosacral fusion Methods: : Ten consecutive patients underwent L5-S1 interbody fusion using the OLIF technique in our institution. The L5–S1 disc space is approached via one retroperitoneal oblique corridor between the psoas muscle and the great vessels. The discectomy and endplate preparation are performed through a surgical window developed on the anterolateral side of L5-S1 disc. A secondary cage insertion technique is used for safe placement of interbody fusion cages. Results: : Of the 10 patients, 6 were males and 4 were females, with an average age of 55.4±6.8 years. There were 8 single-level and 2 two-level procedures, including 2 at L4–L5 and 10 at L5–S1. Preoperative axial MR images confirmed 1 patient with type I LCIV (left common iliac vein), 6 with type II LCIV and 3 with type III LCIV. The average blood loss was 133.4±88.5 ml, and the average operative times were 153.6±38.3 minutes. Postoperative radiographs examination confirmed all patients obtained a better reconstruction at the lumbosacral junction. Two patients with type III LCIV sustained iliolumbar vein laceration during the exposure, and no other perioperative complications were encountered. Conclusion: Our novel OLIF L5-S1 technique is a more feasible procedure of lumbosacral fusion, which shared the common surgical plane with OLIF L2-5, allowing for L2 to S1 reproducible multi-levels interbody fusions via a retroperitoneal oblique corridor between the psoas muscle and the great vessels. Detailed preoperative plan and meticulous intraoperative manipulation are prerequisite for the success of OLIF L5-S1 procedure.