General Session: Adult Spinal Deformity

Presented by: J.H. Oren - View Audio/Video Presentation (Members Only)


J.H. Oren(1), L.M. Day(2), J.F. Baker(3), N.A. Foster(4), M. Moses(5), S. Ramchandran(6), D.L. Cruz(7), C.M. Jalai(8), P.G. Passias(6), S. Bess(9), T.J. Errico(6), T. Protopsaltis(6)

(1) SBH Health System, Orthopedic Surgery, Bronx, NY, United States
(2) SUNY Downstate College of Medicine, Brooklyn, NY, United States
(3) Auckland City Hospital, Department of Orthopaedic Surgery, Auckland, New Zealand
(4) Duke University Medical Center, Orthopedic Surgery, Durham, NC, United States
(5) New York Langone Medical Center, New York, NY, United States
(6) Hospital for Joint Diseases at NYU Langone Medical Center, Department of Orthopaedic Surgery, New York, NY, United States
(7) Temple University Hospital, Department of Orthopaedic Surgery and Sports Medicine, Philadelphia, PA, United States
(8) University of Vermont College of Medicine, Burlington, VT, United States
(9) Denver International Spine Center, Denver, CO, United States


Summary: Adult spinal deformity (ASD), measured with global parameters like the SVA and T1-Pelvic Angle (TPA), correlates with worse health related quality of life (HRQL). Preoperative planning and intraoperative verification of alignment goals is crucial to obtaining optimal postoperative outcomes. Pelvic Incidence-Lumbar Lordosis (PI-LL) mismatch has been the traditional intraoperative measure to assess adequate correction. This study shows that intraoperative measurements of TPA and its component angles, T4PA and T9PA, correlate better to postoperative global alignment than PI-LL.

Hypothesis: Intraoperative TPA measurements will predict postop global alignment after ASD surgery. Design: Retrospective review of an ASD database.

Introduction: Alignment in ASD is associated with disability; global parameters such as SVA and TPA correlate with HRQL. Preop planning and intraop verification of planned correction are crucial to obtain good postoperative outcomes. To date, only measurement of PI-LL has been utilized to assess adequacy of the intraoperative correction. This study uses TPA and its component angles, T4PA and T9PA, to assess intraoperative global correction.

Methods: Patients from a single institution were included with ≥4 levels fused. Preop, intraop and postop regional and global alignment measures, including TPA, T4PA, T9PA, SVA, and PI-LL. Measurements were compared preop, intraop and postop. A sub-analysis was performed comparing UIV upper thoracic (UT≥T6) vs lower thoracic (LT≤T7).

Results: 80 ASD pts were included (mean 63.4y, 70% F, mean levels fused 11.9). Pts underwent significant corrections of their deformities (ΔPI-LL=22.0°; ΔTPA=13.8°), For all pts intraop TPA, T4PA and T9PA correlated with postop SVA (range r=.41-.59), whereas intraop PI-LL was r=.38 (all p< .05). For UT all spinopelvic angles and LL were similar intraop to post op (all p>.09). For LT, intraop and postop T9PA and LL were similar (all p>.10) but TPA and T4PA differed (all p< .02). For UT, all intraop and postop spinopelvic angles were strongly correlated (r=0.8-0.9). For LT, intraop to postop correlations for T9PA were strong (r=.83) and TPA, T4PA, and LL were moderate (r=.65-.70). There was a trend toward LT having more reciprocal kyphosis postoperatively (8.1 vs 2.6°, p=.059)

Conclusion: Intraop measurements of TPA and its component angles had better correlations with postop global alignment than PI-LL demonstrating their utility in confirming alignment goals. Reciprocal kyphosis in the unfused segments of LT fusions may account for difference in TPA and T4PA from intraop to postop. For fusions to LT, T9PA were similar intraop to postop and for fusions to UT, all measures including TPA were similar.