General Session: Adult Spinal Deformity

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


P. Passias(1), C. Jalai(1), B. Line(2), G. Poorman(1), J. Scheer(3), S. Horn(1), J. Moon(1), B. Beaubrun(1), J. Smith(4), C. Shaffrey(4), D. Burton(5), K.-M. Fu(6), E. Klineberg(7), R. Hart(8), F. Schwab(9), V. Lafage(9), S. Bess(10), International Spine Study Group

(1) NYU Hospital for Joint Diseases, Orthopaedic Surgery, New York, NY, United States
(2) Rocky Mountain Spine Clinic, Orthopaedic Surgery, Denver, CO, United States
(3) Northwestern University Feinberg School of Medicine, Neurological Surgery, Chicago, IL, United States
(4) University of Virginia Medical Center, Neurosurgery, Charlottesville, VA, United States
(5) University of Kansas School of Medicine, Orthopaedic Surgery, Kansas City, KS, United States
(6) Cornell University School of Medicine, Neurosurgery, New York, NY, United States
(7) University of California, Davis, Orthopaedic Surgery, Davis, CA, United States
(8) Oregon Health and Science University, Orthopaedic Surgery, Portland, OR, United States
(9) Hospital for Special Surgery, Spine Service, New York, NY, United States
(10) Denver International Spine Center, Denver, CO, United States


Background: Non-operative management is a common initial treatment for adult spinal deformity (ASD) patients despite reported superiority of surgery with regard to outcomes. Ineffective medical care is a large source of resource drain on the health system. Characterization of ASD patients likely to elect for operative treatment from nonoperative management may allow for more efficient patient counseling and cost savings.

Purpose: To identify deformity and disability characteristics of ASD patients that ultimately convert to operative treatment compared to those that remain non-operative and those that initially choose surgery.

Study Design/Setting: Retrospective review.

Patient Sample: 510 ASD patients (189 non-operative, 321 operative) with minimum 2-year follow-up.

Outcome Measures: Oswestry Disability Index (ODI), Short-Form 36 Health Assessment (SF-36), Scoliosis Research Society questionnaire (SRS-22r), and spino-pelvic radiographic alignment.

Methods: Demographic, radiographic and patient-reported outcome measures (PROMs) from a cohort of ASD patients prospectively enrolled into a multi-center database were evaluated. Patients were divided into 3 treatment cohorts: Non-operative (NON=initial non-operative treatment and remained non-operative), Operative (OP=initial operative treatment), and Crossover (CROSS=initial non-operative treatment with subsequent conversion to operative treatment). NON and OP groups were propensity score matched (PSM) to CROSS for to baseline demographics (age, BMI, CCI). Time to crossover was divided into early (< 1yr) and late (>1yr). Outcome measures were compared across and within treatment groups at 4 time points (baseline, 6-week, 1-, and 2-years).

Results: Following PSM, 118 patients were included (NON=39, OP=38, CROSS=41). Crossover rate was 21.7% (41/189). Mean time to crossover was 394 days. All groups had similar baseline sagittal alignment, but CROSS had larger PI-LL mismatch than NON (11.9° vs. 3.1°, p=0.032). CROSS and OP had similar baseline PROM scores, however CROSS had worse baseline ODI, PCS, SRS-22r (p< 0.05). At time of crossover, CROSS had worse ODI (35.7 vs. 27.8) and SRS Satisfaction (2.6 vs. 3.3) compared to NON (p< 0.05). Alignment remained similar for CROSS from baseline to conversion however PROMs (ODI, PCS, SRS Activity/Pain/Total) worsened (p< 0.05). Early and late crossover evaluation demonstrated CROSS-early (n=25) had worsening ODI, SRS Activity/Pain at time of crossover (p< 0.05). From time of crossover to 2yr follow-up, CROSS-early had less SRS Appearance/Mental improvement compared to OP. Both CROSS-early/late had worse baseline, but greater improvements, in ODI, PCS, SRS Pain/Total compared to NON (p< 0.05). Baseline alignment and disability parameters increased crossover odds - NON with Schwab T/L/D curves and ODI≥40 (OR: 3.05, p=0.031), and NON with high PI-LL modifier grades (´+´/´++´) and ODI≥40 (OR: 5.57, p=0.007) were at increased crossover risk.

Conclusions: High baseline and increasing disability over time drives conversion from non-operative to operative ASD care. CROSS patients had similar spinal deformity but worse PROMs than NON. CROSS achieved similar 2-year outcome scores as OP. Profiling at first visit for patients at risk of crossover may optimize physician counseling and cost savings. Levels of Evidence: III