Basics of Oblique Lateral Interbody Fusion at L5/S1 (OLIF51) and Its Pitfalls

The anterior lumbar spinal fusion (ALIF) has been an established surgical modality providing wide access to the L5/S1 intervertebral disc and a high fusion rate since the 1960s [1, 2]. The classical ALIF procedure is basically divided into two approaches, transabdominal and retroperitoneal, and each has advantages and disadvantages. The transabdominal ALIF requires the exposure of intra-abdominal organs with the possible risk of their injuries and subsequent adhesions. The occurrence of retrograde ejaculation was reported to be higher in the transabdominal approach (12–22%) compared to the retroperitoneal approach (2%) [3]. The retroperitoneal approach is able to avoid the exposure of intra-abdominal organs; however, the access to the L5/S1 disc requires vascular manipulation, and it sometimes accompanies the difficulty in obese patients. The OLIF51 was developed to facilitate this approach in the lateral decubitus position, in which intra-abdominal organs move downward [4]. Additionally, the contiguous OLIF procedures from cephalad to caudal levels are possible in a single lateral decubitus position [5, 6]. Since the OLIF51 approach requires direct retraction of surrounding vascular structures, it is a specialized technique that demands careful preoperative assessment and a thorough understanding of anatomical relationships to minimize the risk of vascular injury. This chapter provides an overview of the necessary preoperative assessments, fundamental surgical techniques, and potential pitfalls of the OLIF51 technique.