Is Achieving Optimal Spinopelvic Parameters Necessary to Obtain Substantial Clinical Benefit: Analysis of Patients who Underwent Circumferential MIS or Hybrid Surgery with Open Posterior Instrumentation

Presented at SMISS Annual Forum 2018
By Paul Park MD
With Robert Eastlack MD, Kai-Ming FU MD, Stacie Tran , Gregory Mundis MD, Juan Uribe MD, Michael Wang MD, Khoi Than MD, David Okonkwo MD, Adam Kanter MD, Pierce Nunley MD, Neel Anand MD, Richard Fessler MD, Dean Chou MD, Praveen Mummaneni MD, International Spine Study Group MD,

Disclosures: Paul Park MD B; Biomet, Globus, Medtronic, Nuvasive. F; Globus Robert Eastlack MD A; Nuvasive. B; Aesculap/B. Braun, Alphatec, K2M, Nuvasive, Seaspine, Stryker, Titan. D; Alphatec, Carevature, DiFusion, Invuity, Spine Innovations. F; Globus, Kai-Ming FU MD B; Medtronic. C; Synthes, Stacie Tran None, Gregory Mundis MD A; Nuvasive, ISSGF. B; K2M, Nuvasive. C; K2M, Nuvasive, Depuy. F; K2M, Nuvasive, Juan Uribe MD A; Nuvasive. B; Nuvasive. C; Nuvasive. D; Nuvasive. F; Nuvasive, Michael Wang MD B; Aesculap/B. Braun, Depuy, JoiMax, K2M. C; Depuy. D; Spinicity. F; Depuy, Khoi Than MD None, David Okonkwo MD B; Nuvasive. F; Biomet., Adam Kanter MD A; Nuvasive. F; Nuvasive, Zimmer-Biomet., Pierce Nunley MD B; K2M. C; K2M, LDR. D; Amedica, Paradigm Spine, Spineology. F; K2M., Neel Anand MD B; Medtronic. C; Globus, Medtronic. D; Atlas Spine, Globus, GYS Tech, Medtronic, Paradigm Spine, Theracell. F; Elsevier, Globus, Medtronic., Richard Fessler MD B; Depuy. F; Depuy, Medtronic, Stryker., Dean Chou MD B; Globus, Medtronic. F; Medtronic., Praveen Mummaneni MD B; Depuy. C; Globus. D; Spinicity. F; Globus., International Spine Study Group MD A; Biomet, Depuy, K2M, Medtronic, Nuvasive, Orthofix, Stryker.,


It has been proposed that achieving optimal spinopelvic alignment is needed to attain clinical improvement. This study assessed whether obtaining optimal spinopelvic alignment was necessary to achieve a minimal clinically important difference (MCID) or substantial clinical benefit (SCB).


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).


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 48.3 mm, 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.