Spine Surgeon NYU School of Medicine New Canaan, Connecticut, United States
Disclosure(s):
Peter G. Passias, MD: Cerapedics: Consultant (Ongoing); Globus Medical: Consultant (Ongoing); Journal of Neurosurgery: Spine: Board Member/Officer/Trustee (Ongoing); Medtronic: Consultant (Ongoing); Nuvasive: Consultant (Ongoing); Royal Biologics: Consultant (Ongoing); Spine: Board Member/Officer/Trustee (Ongoing); Terumo: Consultant (Ongoing)
Introduction: Previous literature has linked high pelvic incidence(PI) to problematic outcomes following corrective surgery, including mechanical complications and hip pathologies. We sought to determine if patients with high pelvic incidence have increased risk for complications and poor radiographic outcomes following ASD surgery.
Methods: ASD patients with 2-year(2Y) data were stratified into two Groups: PI>65°(HighPI) versus PI < 65°(LowPI). Means comparison tests assessed differences in demographics, surgical details, and outcomes between groups. Multivariable analysis controlling for baseline age and frailty analyzed complication rates and radiographic alignment between the cohorts. Groups were propensity score-matched(PSM) for frailty, history of prior fusion, BL PI-LL, and surgical invasiveness.
Results: We included 445 ASD patients with 94(21%) being HighPI. HighPI patients were more likely to have had a prior fusion(OR: 1.9,[1.2-3.1]), present with lower physical functioning scores, severe pelvic compensation(OR: 5.5,[3.4-8.9]) and global deformity(OR: 3.5,[2.2-5.6]). HighPI patients underwent more 3COs(OR: 1.8,[1.1-3.1]) and fusion to pelvis(OR: 2.1,[1.1-3.9]). Adjusted analysis revealed HighPI group was more likely to be undercorrected in each age-adjusted parameter compared to LowPI(OR: 4.8,[2.9-7.8]). HighPI patients were less likely to deteriorate within in-construct PI-based alignment(relative lordosis and lordosis distribution) (OR: 0.3,[0.1-0.9]). HighPI cohort was more likely to deteriorate in global alignment and pelvic compensation within two years(OR: 3.2,[1.6-6.5]). This translated to a higher likelihood of developing a major or mechanical complication by 2Y(OR: 1.6,[1.04-2.6]). After PSM, HighPI patients were more likely to deteriorate in PI-based alignment(OR: 1.8,[1.02-5.5]), but were no longer more likely to experience a mechanical or major complication(p>.7).
Conclusion : High pelvic incidence is associated with increased frailty, decreased physical functioning, and more severe lumbopelvic and global deformity upon presentation for adult spinal deformity correction. Especially when presenting for a revision, these patients are more often undercorrected by age-adjusted standards and deteriorate in out-of-construct alignment over time even when adequately corrected, leading to higher mechanical complications by two years.
