Analysis of Spino-Pelvic Parameters and Segmental Lordosis with L5-S1 Oblique Lateral Interbody Fusion at the Bottom of a Long Construct in Circumferential Minimally Invasive Surgical Correction of Adult Spinal Deformity

Abstract

Lateral interbody fusion (LIF) is an effective adjuvant for circumferential minimally invasive surgery (CMIS) treatment of adult spinal deformity (ASD). Accessing L5-S1 via an oblique LIF (OLIF) approach (OLIF 5-1) allows for anterior LIF (ALIF) at the lumbosacral junction without repositioning the patient. We review the early outcomes and complications of OLIF 5-1 at the bottom of a long construct for an MIS approach to treat ASD. We queried a prospectively collected registry of 111 consecutive patients with ASD (Cobb angle >20°, sagittal vertical alignment [SVA] >50, or pelvic incidence [PI]-lumbar lordosis [LL] mismatch>10) patients who underwent CMIS correction between January 2015 and January 2019. Sixty patients had ≥4 levels fused and OLIF 5-1. Multilevel pre-psoas LIF+ OLIF 5-1 were performed in the first stage. Three days later, stage 2 involved MIS installation of pedicle screws with aggressive rod contouring and derotation/translation. The mean patient age was 66.8 years (range, 48-79 years), and the mean duration of follow-up was 24 months (range, 3-60 months). A mean of 7 levels were fused (range, 4-9). Significant improvements in L5-S1 segmental lordosis (SL), LL, SVA, PI-LL mismatch, and pelvic tilt were seen following the first stage (P < 0.05). There was no intraoperative vascular, ureteral, or sympathetic chain injury, and no transient or permanent lumbar plexopathy. In 2 patients, OLIF 5-1 was abandoned due to difficult access, and transforaminal LIF was done at L5-S1 at the second stage. Five patients required intraoperative transfusion. No patient experienced postoperative ileus or L5-S1 pseudarthrosis. Significant improvements in visual analog scale pain score, Oswestry Disability Index, 36-Item Short Form Health Survey, and Scoliosis Research Society Outcomes Questionnaire were found. A single-position MIS OLIF 5-1 at the bottom of a long construct in conjunction with multilevel pre-psoas LIF seems to be a safe and effective technique for improving SL, global LL, and SVA with a low risk of perioperative and postoperative complications.