PURPOSE: Adult spinal deformity (ASD) impacts patients' quality-of-life. Minimally invasive surgery (MIS) can adequately treat carefully selected patients with ASD. Stand-alone lateral interbody fusion has been found effective in the treatment of low-grade degenerative spondylolisthesis, degenerative lumbar scoliosis as well as other degenerative spine conditions. However, the efficacy of anterolateral interbody fusion as an alternative approach to open spinal deformity correction has not been fully explored. Herein, the outcomes of patients who underwent standalone MIS anterolateral fusion were evaluated.
METHODS: Patients with planned two-stage scoliosis correction from 2019 to 2021 were reviewed. Those whose preoperative symptoms improved after first-stage anterolateral MIS and did not undergo posterior fixation were identified. Spinopelvic parameters were measured with 36-inch-standing films. Oswestry disability index (ODI), visual analog scale (VAS) back and leg, and Scoliosis Research Society (SRS) average subdomain scores were collected.
RESULTS: Eleven patients (3:8, male: female) were included. Mean age was 62.9 ± 8.0 years, BMI was 31.3 ± 4.3 kg/m2, and follow-up was 18.5 ± 12.6 months. Average preoperative spinopelvic parameters were: C7-sagittal vertical axis (C7-SVA) 51 mm, C7-sagittal-center vertical line (C7-SVL) 18.7 mm, pelvic incidence (PI) 47°, lumbar lordosis (LL) 36°, PI-LL mismatch 11°, pelvic tilt (PT) 23°, and coronal Cobb angle (CCA) 34°. Average spinopelvic parameters at first radiographic follow-up were: C7-SVA 29 mm (p = 0.002), C7-SVL 8 mm (p = 0.005), PI 47° (p = 0.455), LL 57° (p = 0.001), PI-LL mismatch -9.5° (p = 0.002), PT 18° (p = 0.004), and CCA 24° (p = 0.011). Besides lower LL, smaller PI-LL mismatch, and higher PT, there were no significant differences in radiographic parameters between first and last postoperative imaging. Significant improvements in ODI, VAS back and leg, and SRS average subdomain scores were identified (p < 0.05). No patients required hardware revision or second-stage fixation.
CONCLUSIONS: In select patients with adult spinal deformity, standalone anterolateral MIS fusion yielded enough radiographic correction and clinical improvement to defer or avoid the second stage of fusion. Longer-term follow-up and more studies are needed to establish its efficacy as a standard-of-care procedure.