Nuances of oblique lumbar interbody fusion at L5-S1: Three case reports

BACKGROUND: Oblique lumbar interbody fusion is a mini-open retroperitoneal approach that uses a wide corridor between the left psoas muscle and the aorta above L5. This approach avoids the limitations of lateral lumbar interbody fusion, is considered less invasive than anterior lumbar interbody fusion, and is similarly effective for indirect decompression and improving lordosis while maintaining a low complication profile. Including L5-S1, when required, adds to these advantages, as this allows single-position surgery. However, variations in vascular anatomy can affect the ease of access to the L5-S1 disc. The nuances of three different oblique anterolateral techniques to access L5-S1 for interbody fusion, namely, left-sided intra-bifurcation, left-sided pre-psoas, and right-sided pre-psoas approaches, are illustrated using three representative case studies. CASE SUMMARY: Cases of three patients who underwent multilevel oblique lumbar interbody fusion including L5-S1, using one of the three different techniques, are described. All patients presented with symptomatic degenerative lumbar pathology and failed conservative management prior to surgery. The anatomical considerations that affected the decisions to utilize each approach are discussed. The pros and cons of each approach are also discussed. A parasagittal facet line objectively assesses the relationship between the left common iliac vein and the L5-S1 disc and assists in choosing the approach to L5-S1. CONCLUSION: Oblique retroperitoneal access to L5-S1 in the lateral decubitus position is possible through three different approaches. The choice of approach to L5-S1 may be individualized based on a patient’s vascular anatomy using preoperative imaging. While most surgeons will rely on their experience and comfort level in choosing the approach, this article elucidates the nuances of each technique.