Abstract
It has been proposed that achieving optimal spinopelvic alignment is needed to attain significant clinical improvement.
The purpose of this study was to determine whether obtaining optimal spinopelvic alignment was necessary to achieve a minimal clinically important difference (MCID) or substantial clinical benefit (SCB).
Multicenter retrospective review.
A total of 153 patients who underwent less invasive surgery for adult spinal deformity (ASD).
Oswestry Disability Index.
Inclusion criteria were age ≥18 years, and one of the following: coronal Cobb>20°, SVA>5cm, PT>20°, PI-LL>10°. Patients were treated with circumferential MIS or hybrid surgery and had 2-year minimum follow-up. Based on optimal spinopelvic parameters (PI-LL±10°, PT<20°, SVA<5cm), patients were divided into aligned (AL) or mal-aligned (MAL) groups. MCID and SCB were defined as a 12.8 and 18.5 ODI improvement, respectively.
There were 74 AL and 149 MAL patients. Age and BMI were similar between groups. Although baseline SVA was similar, PI-LL (9.9° vs. 17.7°, p=0.002) and PT (19° vs. 24.7°, p=0.001) significantly differed between AL and MAL groups, respectively. As expected postoperatively, the AL and MAL groups differed significantly in PI-LL (−0.9° vs. 13.1°, p<0.001), PT (14° vs. 25.5°, p=0.001), SVA (11.8mm vs. 48.3mm, p<0.001), respectively. Notably, there was no difference in the proportion of AL or MAL patients who achieved MCID (52.75 vs. 61.1%, p>0.05) or SCB (40.5% vs. 46.3%, p>0.05), respectively. On multivariate analysis controlling for surgical and preop demographic differences, achieving optimal spinopelvic parameters was not associated with achieving MCID (OR 0.645, 0.31–1.33, 95%CI) or SCB (OR 0.644, 0.31–1.35, 95%CI) ODI.
Achieving optimal spinopelvic parameters does not appear to be a predictor for achieving MCID or SCB. Since spinopelvic parameters are correlated with clinical outcomes, our findings suggest that the presently accepted optimal spinopelvic parameters may require modification.