Analysis of The Correction Capability of Oblique Lumbar Interbody Fusion Approach to Improving The Lenke-Silva Classification in First-Stage MIS Adult Spinal Deformity Corrections

Abstract

\n BackgroundA two-stage minimally invasive surgery (MIS) protocol with oblique lumbar interbody fusion (OLIF) combined with posterior instrumentation is becoming popular in the treatment of adult spinal deformities (ASDs) because of lower complication rates and less blood loss when compared with the open traditional posterior approach. The objective of this study is to determine the efficacy of correction and the causes of suboptimal correction in two-stage OLIF.MethodsThis retrospective study included 27 patients who underwent both two-stage and single-stage OLIF with posterior instrumentation for treatment of ASD. Patients treated with two-stage OLIF were sorted into Group A (Improved Lenke-Silva classification after the first-stage OLIF) and Group B (Unchanged Lenke-Silva classification after the first-stage operation) to evaluate the correction efficacy of OLIF in a two-stage MIS protocol. Statistical analyses were performed to compare the clinical and radiological outcomes. The causes of complications and suboptimal corrections (Group B) in patients treated with the two-stage MIS protocol were analyzed.ResultsAll 27 patient patients showed significant improvement (P < 0.05) in the visual analog scale, the Oswestry Disability Index, and EuroQol. A total of 14 patient were treated with the two-stage protocol, with ten patients included in group A and four patients with insufficient correction angles included in group B. The radiographic outcome of Group A showed significant corrections (P < 0.05) in pelvic tilt, pelvic incidence-lumbar lordosis (PI-LL) mismatch, sagittal vertical axis, and max Cobb angles. In group B, surgical limitations of OLIF were the cause of unsatisfactory correction in two patients because the deformities involved the T-L junction, which was not accessible using the approach. Severe preoperative PI-LL mismatch (41°) and cage subsidence with an anterior endplate fracture were the cause of poor correction in two other patients.ConclusionOLIF can provide significant corrections that reduce the need for a Smith-Petersen osteotomy (SPO) or a pedicular subtraction osteotomy (PSO) for additional correction during posterior instrumentation. Deformities involving the T-spine or T-L junction, severe PI-LL mismatches, and cage subsidence are the possible causes of suboptimal corrections with OLIF using the two-stage protocol.