Spine Surgeon Learning Curve with L5-S1 Lateral ALIF (OLIF51) Surgical Approaches: Perioperative Outcomes and Complications

Introduction: Lateral anterior lumbar interbody fusion (ALIF), also known as oblique lumbar interbody fusion at L5-S1 (OLIF51), is a minimally invasive approach between the iliac vessels that provides a powerful option for indirect decompression, restoration of alignment, and lordosis. While the supine ALIF exposure has historically been performed by vascular surgeons, minimally invasive lateral ALIF exposure has increasingly become a technique performed by spine surgeons familiar with lateral interbody approaches at other levels.

Methods: This retrospective case series includes the first 45 patients who underwent lateral ALIF at or including L5-S1 by the senior author MHP. Operative time, perioperative complications, and clinical and radiographic results were collected. Patients were also analyzed based on the author’s first 1-22 patients (group A) and last 23-45 patients (group B).

Results: Demographic analysis showed a mean age of 59.8 (range 28-80), mean BMI of 28.8 (range 19.1-48.6), with 53% female (24 patients). Diagnosis was degenerative in 32 patients and deformity in 13 patients; all degenerative patients also underwent lateral single position surgery (SPS) with posterior fixation in the same setting. Twelve patients underwent single interbody level fusions at L5-S1, 20 patients at 2 interbody levels, 13 patients at 3-6 interbody levels. Segmental L5-S1 lordosis increased by 12.6° ± 4.7° with a final mean segmental lordosis of 23.7° ± 8.3°. There were no significant differences in operative times for degenerative 1-level or 2-level SPS operations between groups A and B (3h 13m vs. 3h 10m p=0.43, 4h 29m vs. 4h 40m p=0.39, respectively) or estimated blood loss (54 cc vs. 63 cc p=0.30, 81 cc vs 88 cc p=0.32). Two incisional hernias requiring repair occurred in group A with none in group B. Postoperative ileus occurred in 2 patients (4.4%). There were no approach-related vascular, bowel, ureteral, or neurologic injuries, and no intraoperative blood transfusions needed.

Conclusion : With good patient selection and meticulous technique, the minimally invasive lateral ALIF approach at L5-S1 can be performed by spine surgeons already experienced with lateral access approaches to other levels of the lumbar spine.