67. Lateral lumbar interbody fusion with percutaneous pedicle screw fixation (LLIF-PPS): are we getting the sagittal alignment right?

Abstract

BACKGROUND CONTEXT Lateral lumbar interbody fusion with percutaneous pedicle screw fixation (LLIF-PPS) is a circumferential minimally-invasive surgery (MIS) that achieves indirect decompression, stabilization and interbody fusion for treatment of lumbar pathologies. Advantages of MIS include lower blood loss, less postoperative pain, and quicker recovery. Attaining proper sagittal alignment with spinal fusion has been shown to strongly correlate with surgical outcomes and is thus an important goal in spinal fusion. PURPOSE We evaluated the efficacy of LLIF-PPS in achieving optimal sagittal alignment. STUDY DESIGN/SETTING Retrospective radiographic analysis. PATIENT SAMPLE Eighty-four patients (115 levels) who underwent LLIF-PPS by 2 surgeons at 2 institutions (2009- 2018) were included in the study. Exclusion criteria were: concomitant ALIF/TLIF; corrective osteotomies; pre-psoas approach; planned anterior longitudinal ligament release; extension of fixation to the thoracic spine or pelvis; and fusion for discitis, osteomyelitis or acute trauma. OUTCOME MEASURES Pre- and postoperative radiographs were analyzed for mean number of alignment goals met using the following criteria: (1) PI-LL = 60% of PI. METHODS Preoperative and 6- to12-week postoperative standing lateral spine radiographs were evaluated for the following parameters: lumbar lordosis (LL), pelvic incidence (PI), pelvic tilt (PT) and L4-S1 lordosis. The frequency that each of 3 sagittal alignment criteria was met in pre- and postoperative radiographs was recorded. RESULTS There was no difference in rate of meeting specific alignment goals before and after LLIF-PPS (p > 0.05 for all three criteria). Average number of goals met was higher pre- than postoperative (1.68 vs 1.48, p = 0.03). Postoperative, 51% of patients met the same number of alignment goals, 17% met more and 31% met fewer, compared to their preoperative state. CONCLUSIONS There was no difference in frequency of meeting alignment goals before and after LLIF-PPS. Fewer cumulative alignments goals were met after LLIF-PPS. These findings suggest that LLIF-PPS generally is not able to correct sagittal malalignment, and that patients with preoperative sagittal malalignment should be considered for additional procedures (eg, osteotomies) that provide more significant correction of lordosis. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.