Achievement and Maintenance of Optimal Alignment Following Adult Spinal Deformity Corrective Surgery: A 5 Year Outcome Analysis

Thursday, June 1, 2023

8:30 AM – 6:15 PM

Location: Salons 7-8

Co-Author(s)

JM

Jamshaid M. Mir, MD

Research Fellow
NYU Langone Health | NY Spine Institute, United States
PT

Peter S. Tretiakov, BS

United States
PD

Pooja R. Dave

Miami, Florida, United States
DC

Daniel Chen, n/a

United States
GM

Giorgos D. Michalopoulos, MD

Minnesota, United States
RL

Renaud Lafage, MS

Senior Biomedical engineer
Lenox Hill Hospital
new york, New York, United States
SO

Stephane Owusu-Sarpong, MD

Orthopedic Surgery Resident
NYU Langone Health, United States
JL

Jordan Lebovic, MD, MBA

Resident
NYU Langone Orthopedics
New York, New York, United States
SV

Shaleen Vira, MD

Assistant Professor, Orthopaedic Surgery & Neurosurgery
UT Southwestern Medical Center
Dallas, Texas, United States
MJ

M. Burhan Janjua

United States
AM

Angel Macagno

United States
TR

Timothy Roberts

Orthopaedic Spine Surgeon
Westbury, New York, United States
AS

Andrew Schoenfeld

United States
Virginie Lafage, PhD

AVP, Clinical Research
Lenox Hill | Northwell
Hospital for Special Surgery
New York, New York, United States

Presenting Author (Person doing the Podium Present(s)

PP

Peter G. Passias, M.D.

Spine Surgeon
NYU Langone Orthopedic Hospital
New York, New York, United States

View E-Poster

Submitter(s)

PP

Peter G. Passias, M.D.

Spine Surgeon
NYU Langone Orthopedic Hospital
New York, New York, United States

View E-Poster

Disclosure(s):

Peter G. Passias, MD: No relevant disclosure to display

Introduction: Assessment of factors associated with maintenance of optimal alignment till five year post adult spinal deformity (ASD) surgery can provide insight to components that lead to durable outcomes.

Purpose: To assess factors contributing to optimal radiographic and functional outcomes.
Study Design/Setting: Retrospective cohort
Patient Sample: Operative ASD single center database

Methods: Operative ASD patients with preoperative baseline and at least 5-year data were included. Durable alignment (D) was defined as improving in at least one SRS-Schwab modifier without worsening in any SRS-Schwab modifier. A robust outcome was defined as having durable alignment at 2Y that maintained it at 5Y. Means comparison tests assessed differences in demographic and clinical data between the robust and non-robust groups. Predictors of robust outcomes were identified using multivariate regression analysis, with conditional inference tree (CIT) for continuous variables.

Results: 297 ASD patients met inclusion criteria (59.3±14.9yrs, 79%F, BMI 27.1±5.5kg/m2, CCI: 1.6±1.7, ASD-mFI: 6.5±4.9) and underwent surgery (levels fused 11.0±4.5, EBL 1547mL, op time 418min). 49% had a staged approach, with 1.1% undergoing anterior, 63.2% posterior-only and 35.7% combined. BL SRS-Schwab modifiers assessment found 36.4% ++PI-LL, 31.8% ++SVA, 25.1% ++PT. At 5Y postop: 12.1% ++PI-LL, 10.6% ++SVA, 17.6% ++PT. By Lafage et al. age-adjusted alignment goals, 20.7% were matched at 5Y.
77.4% met D at 6W, 54.2% met radiographic durability at 2Y, while 89.4% of those went on to meet radiographic durability at 5Y (48.5% of total cohort). Durable outcome cohort at 5Y was younger, had lower BMI and frailty (all p< 0.05). Those that did not achieve D2 had higher rates of reoperations due to implant failure (10% vs 4%, p=0.024) and sagittal imbalance (4% vs 0%, p=0.014).
Rates of junctional failure were 70% in those that did not achieve D5 when met at D2, compared to 33.3% in those that met both (p=0.013), with reoperation rates of 17.2% due to loss of alignment. Major complication due to pseudarthrosis were also higher in those that failed to achieve 5Y durability after meeting 2Y, (6% vs 1%, p=0.069).
Multivariate regression controlling for gender, baseline age, BMI, CCI, osteoporosis, frailty, invasiveness, BL PT, SVA, and PI-LL, and prophylaxis identified the following independent predictors of durability of alignment at 5Y in those that achieved 2Y: BL to 6W decreased correction in PT, and increased correction in PI-LL (p < 0.05). Increased age, BMI, and invasiveness were the most significant non-radiographic predictors for not achieving 5Y durability (Age OR: 1.025 [1.002-1.049], p=0.032, BMI OR: 1.098 [1.017-1.185], p=0.016, Invasiveness OR: 1.028 [1.015-1.041], p< 0.001).

Conclusion:
Durability of achieving optimal alignment following corrective ASD surgery was sustained in half of the patients at 5 years. While the majority of patients at 2 years sustained their radiographic outcomes at 5 years, major contributors to loss of alignment included junctional failure and adjacent region compensation, with only a minority of patients losing correction through the existing construct. Reoperation rate for loss of alignment was 17.2%. Loss of alignment requiring reoperation had a detrimental effect on 5 year clinical outcomes.