Do interbody devices that traverse the lumbar apex result in improved outcomes and alignment in adult spinal deformity

BACKGROUND CONTEXT: Interbody devices (IBD) are commonly used to correct deformity and are more often employed distally at the lumbosacral junction. Assessment of the impact on alignment and outcomes for IBD placed distal to the lumbar lordosis apex relative to those that have an extension of IBD proximal to the apex remains to be evaluated. PURPOSE: To evaluate whether patients with IBD placed distal to lumbar lordosis apex improved complication rates and outcomes. STUDY DESIGN/SETTING: Retrospective cohort study of a prospectively collected single-center adult spinal deformity database. PATIENT SAMPLE: ASD. OUTCOME MEASURES: Outcomes, complications. METHODS: Operative ASD patients fused from at least L1 and proximal to sacrum were included with complete two-year data. Patients were stratified based on IBD device distal (D) to postoperative lumbar lordosis apex or proximal (ND) in those who had IBD. Achievement and maintenance of alignment, along with improvement in HRQLs and complications were assessed. Descriptive and means comparison analyses were used. ANCOVA and multivariable logistic regression were utilized to control for age, gender, BMI, osteoporosis, CCI, frailty, and baseline deformity (C7-PLA, PI, PI-LL, PT, SVA, TPA). RESULTS: A total of 320 patients met inclusion. (Age 64±9, 78% F, BMI 27.5±5.1 kg/m2, frailty 7.3±4.7, CCI 1.9±1.7). 59% had IBD distal to the apex (D). D was younger (63.2 vs 65.3), had lower BMI (27.0 vs 28.2), CCI (1.8 vs 2.0), and frailty (6.6 vs 8.3) (all p<.05). Baseline deformity in D was lower in T1PA (24.5 vs 28.0, p=.016), with no difference in PT, PI, or PI-LL. No difference in posterior levels fused (mean 12.4), however a greater proportion of ND had osteotomies (88% vs 73%), a greater mean number of 3CO (0.34 vs 0.20), and a lower number of IBs (1.1 vs 2.6) (all p<.05). Mechanical complication rates did not vary amongst D and ND. However, when controlling for covariates, ND had a 2.6x higher likelihood of reoperation due to rod failure or pseudarthrosis (2.613 [1.090-6.264], p=0.031). D had 3x higher odds of achieving MCID in pain (SRS22r pain: 3.316 [1.260-8.725], p=0.015) and 1.6x increased odds of MCID in ODI at 2Y (1.631 [1.021-2.605], p=0.041). CONCLUSIONS: Patients with interbody device extending proximal to the lumbar lordosis apex had lower rates of reoperation for pseudarthrosis and rod fracture, resulting in greater improvement in pain and disability. FDA Device/Drug Status: This abstract does not discuss or include any applicable devices or drugs.

Duke Scholars

Author Christopher Ignatius Shaffrey Orthopaedic Surgery

Author Peter Passias Orthopaedic Surgery