39 - A Critical Analysis of Sagittal Plane Deformity Correction with Minima...

General Session: MIS-3

Presented by: P. Nunley - View Audio/Video Presentation (Members Only)


G. Mundis(1,2), V. Deviren(3), J. Uribe(4), P. Nunley(5), P. Mummaneni(3), N. Anand(6), P. Park(7), D. Okonkwo(8), M. Wang(9), S. Bess(10), A. Kanter(8), R. Fessler(11), S. Nguyen(2), B. Akbarnia(2), J. Zavatsky(2), International Spine Study Group

(1) Scripps Clinic, La Jolla, CA, United States
(2) San Diego Center for Spinal Disorders, San Diego, CA, United States
(3) University of California, San Francisco, San Francisco, CA, United States
(4) University of South Florida, Tampa, FL, United States
(5) Spine Institute of Louisiana, Shreveport, LA, United States
(6) Cedars Sinai, Los Angeles, CA, United States
(7) University of Michigan, Ann Arbor, MI, United States
(8) University of Pittsburgh Medical Center, Pittsburgh, PA, United States
(9) University of Miami, Miami, FL, United States
(10) Rocky Mountain Orthopaedics, Denver, CO, United States
(11) Rush University, Chicago, IL, United States


Hypothesis: Minimally invasive spine surgery is currently unable to achieve optimal sagittal plane correction among patients with significant sagittal plane deformity. Design: Multicenter retrospective case series.

Introduction: Sagittal plane realignment is critical to achieve desired post-operative clinical outcomes. We aim to evaluate circumferential MIS (cMIS) techniques and their ability to treat the sagittal plane with 2-year follow up.

Methods: A retrospective multicenter database from 2009 to 2012 was queried for the following inclusion criteria: cMIS, 2yr followup, coronal Cobb ≥20°, SVA >5cm, or PT>25°. Patients were then stratified by SRS-Schwab global alignment modifier (GAM) as Scoli (coronal deformity; SVA< 4), + (SVA 4-9.5), or ++(SVA>9.5) depending on their preoperative sagittal plane deformity, and analyzed at 2 yrs for demographic, radiographic and HRQoL measures (ODI and NRS back and leg).

Results: 426 patients met inclusion criteria, 86 had complete 2yr data (n: Scoli=51, +=21, and ++=14). The Scoli group was significantly younger than ++ (57.6 v 70.5). There were no differences in baseline HRQoL and operative data. Preoperative radiographic parameters were consistent with GAM stratification (table 1). Postop, Scoli and + had improved ODI, NRS back and leg. Scoli had no differences radiographically while + saw improvement in PI-LL (21.1-15.4; p=0.025) and LL (33.6 - 39.9; p=0.016). ++ had improvement in NRS back but not in ODI, NRS leg, or PT, PI-LL, SVA, or LL. Of 52 pts in Scoli, 42 (81%) remained in Scoli, while 9 (17%) pts deteriorated (5 to +, 4 to ++). 13/21(61.9%) + pts remained + while 3 changed to ++, and 5 to Scoli. 9/14 (64.3%)++ pts remained ++, while 3 improved to + and 2 to Scoli.

Conclusions: Minimally invasive techniques successfully stabilized patients with SRS GAM of Scoli and + deformities and improved HRQoL at 2 years. Patients with substantial deformity ++ showed no improvement clinically after MIS surgery indicating that this group acquired a fixed sagittal plane deformity.

Table 1