193. Comprehensive alignment planning (CAP) for adult spinal deformity (ASD) more effectively predicts surgical outcomes and proximal junctional kyphosis than previous classifications

Abstract

BACKGROUND CONTEXT Several methodologies have been proposed to determine ideal adult spinal deformity (ASD) sagittal spinopelvic alignment, two of them being; (1) patient age adjusted alignment based on pelvic incidence-lumbar lordosis (PI-LL), and sagittal vertical alignment (SVA) and (2) global alignment and proportion (GAP) score (a calculator initially developed to assess proximal junctional kyhosis [PJK] risk). A recent study evaluating the ability of different methodologies to predict PJK highlighted GAP inability to effectively predict PJK outside the original GAP creation data set. PURPOSE Investigate a novel methodology (comprehensive alignment planing, or CAP) that utilizes a hybrid approach to assess ASD alignment by combining age adjusted alignment thresholds with concurrent alignment parameters. STUDY DESIGN/SETTING Retrospective review of a prospective ASD database. PATIENT SAMPLE Surgically treated ASD patients minimum 2-year follow-up. OUTCOME MEASURES Sagittal alignment, ODI, SF-36, SRS-22r, proximal junctional kyphosis/failure, CAP and GAP scores. METHODS Multicenter ASD database was evaluated for surgically treated ASD patients with (1) fusion with a minimum of 5 levels, (2) fusion to pelvis, and (3) minimum 2-year follow-up. The CAP scoring methodology was created by assigning numerical values to the difference between each patient's postoperative sagittal alignment and ideal alignment as defined by previously reported age generational norms for PI-LL, PT, and TPA. CAP score ranges from −3 (if a patient is under corrected for all 3 parameters by at least 10 years) to +9 (if a patient is overcorrected by at least 30 years in all 3 parameters). A cumulative CAP score −1 to +2 represents unity between patient postop alignment and age alignment targets, CAP≤-2 represents under-correction, and CAP>+2 represents overcorrection. Postoperatively, PJK severity was categorized as None, PJK (angle 10°), Severe-PJK (28°), and PJF (PJK treated surgically). Postop HRQOL and PJK severity between each GAP and CAP categories were evaluated. RESULTS Four hundred and nine667 patients meeting inclusion criteria were evaluated. Preoperatively most of the patients had moderate to severe deformity per SRS-Schwab modifiers (PT: 26°, PI-LL=20°, and SVA=80 mm). At 2 years, mean CAP score increased from −0.8±2.4 to +0.8±2.9 (p CONCLUSIONS Evaluation of a novel ASD alignment assessment tool (CAP) demonstrates improved ability to predict the occurrence and severity of PJK compared to previously reported tools. Additionally the CAP tool correlates well with postoperative patient outcomes including HRQOL. The CAP tool may aid ASD surgical planning via use of age-adjusted alignment parameters allowing surgeons to target a postoperative alignment that minimizes complications and optimize surgical outcomes. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.