Assessing Differences in Junctional, Instrumentational, and Pseudoarthrosis Failure in Adult Spinal Deformity Surgery: Comparative Analysis of Failure Rates, Reoperation, and Disability Recovery

Thursday, June 1, 2023

8:30 AM – 6:15 PM

Location: Salons 7-8

Co-Author(s)

PT

Peter S. Tretiakov, BS

United States
JM

Jamshaid M. Mir, MD

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

Pooja R. Dave

Miami, Florida, United States
MJ

M. Burhan Janjua

United States
JL

Jordan Lebovic, MD, MBA

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

Pawel Jankowski

United States
TP

Themistocles S. Protopsaltis, MD

Chief, Division of Spine Surgery
NYU Langone Health Department of Orthopedic Surgery
New York, New York, United States
AS

Andrew Schoenfeld

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

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Submitter(s)

PP

Peter G. Passias, M.D.

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

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Disclosure(s):

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

Background: Post-operative failure after adult spinal deformity surgery may refer to a variety of complications, including instrumentation failure, junctional failure, or pseudoarthrosis. However, there is a paucity of current literature describing the rates, outcomes, and predictors of optimal outcomes after reoperation different types of failure.

Purpose: To assess rates, patient-reported outcomes, and predictors of achieving optimal clinical outcomes when reoperation is indicated in different types of failure after adult spinal deformity surgery.

Methods: Operative ASD patients ≥18yrs with pre-(BL) and two-year (2Y) postop radiographic/HRQL data were assessed. Patients were categorized as having suffered mechanical failure (Failed) or not (Not Failed) at any point after index surgery. Patients were then subdivided into 3 failure groups: instrumentation failure (rod fracture, screw failure), pseudoarthrosis, or junctional failure [PJF (PJK requiring reoperation or Lafage et al. radiographic PJF)]. Differences in demographics, radiographic parameters, and complication rates were assessed via means comparison analyses. Conditional backstep binary regression analysis was used to identify associated predictive factors of achieving MCID in ODI within each failure subtype controlling for reoperation.

Results: 266 ASD patients met inclusion criteria (60.0±15.1yrs, 79%F, BMI:26.7±5.5kg/m2). Surgically, patients had a mean anterior levels fused of 1.78±1.4, and mean posterior levels fused of 10.4±4.6. 20.7% of patients underwent 3-column osteotomy. In terms of failure rate by 2Y, 10.9% of patients suffered instrumentation failure, 3.8% suffered pseudoarthrosis, and 7.1% suffered PJF. At baseline, cohorts were comparable in age, gender, BMI, ASA grade, and frailty (all p>.05). Operatively, patients who developed pseudoarthrosis were significantly less likely to undergo interbody fusion versus instrumentation or junctional failure patients (30.0% vs 76.0% vs 68.0%, p=.029). Post-operatively, all Failed cohorts demonstrated comparable patient-reported measures per ODI and SRS-22 (p>.05). When controlling for BL age C7-S1 SVA, and reoperation, pseudoarthrosis patients reported significantly higher mean ODI at 1Y. Yet, Failed patients reported significantly higher ODI at 1Y vs Not Failed patients per controlled analysis (p <.05). 59.0% of Failed patients required reoperation, with no significant differences between groups (p>.05). When reoperation is indicated in instrumentation failure patients, decreased age, BL PT, and BL PI-LL only increased BL PT (p=.002) was predictive of instrumentation failure, and increasing age and sacral slope were predictive of achieving MCID-ODI. Decreased age, and lack of 3CO were predictive of MCID-ODI in pseudoarthrosis failure patients. In junctional failure patients, and age-adjusted match at 6W was predictive of meeting MCID-ODI (all models p<.01).

Conclusions: Junctional failure, instrumentational failure, and pseudoarthrosis may adversely affect outcomes after adult spinal deformity surgery and increase the need for reoperation. In this study, failure rates remained below 10% in each subtype, yet each cohort had distinct predictive profiles of achieving minimum clinically important difference (MCID) by ODI when reoperation was required.