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, FACS, Michael Wang MD, Khoi Than MD, David O Okonkwo , 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, Alphatec Spine, K2M, Nuvasive, Seaspine, Stryker, Titan. D; Alphatec, Carevature, DiFusion, Invuity, Nuvasive, Spine Innovations. F; Globus Medical, Kai-Ming FU MD B; Medtronic. C; Synthes, Stacie Tran None, Gregory Mundis MD A; ISSGF, Nuvasive. B; K2M, Medicrea, Misonix, Nuvasive. C; K2M, Nuvasive. F; Nuvasive., Juan Uribe MD, FACS 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 O Okonkwo None, 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 None, 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.