232. Optimal lumbar lordosis correction for adult spinal deformity with severe sagittal imbalance in patients over age 65: role of pelvic tilt and pelvic tilt ratio

Abstract

BACKGROUND CONTEXT The prevalence of adult spinal deformity (ASD) is increasing as the average age of the population increases. Optimal surgical correction for patients with ASD is necessary. The Scoliosis Research Society-Schwab classification is used for optimal surgical correction in many spinal reconstruction surgeries, and the targets to obtain satisfactory alignment and favorable outcomes are ≤10° for pelvic incidence (PI) minus lumbar lordosis (LL), 20°, while pathologic based on Schwab criteria, may be a natural phenomenon in patients with a large PI. Therefore, the concept of global tilt has been introduced recently, and to overcome the limitations of PT in our study, a PT ratio value (PTr) of PT/PI x 100% was calculated along with measurement of PT. PURPOSE The purpose of this study was to evaluate optimal and ideal target values including PTr of the spine balance correction in elderly patients with ASD who were over the age of 65 years. STUDY DESIGN/SETTING Retrospective, consecutive case review. PATIENT SAMPLE A total of 121 patients (average age 70.5 years and a minimum 2-year follow up) with lumbar degenerative kyphosis (LDK) who underwent long-segment fusion from T10 to sacrum. OUTCOME MEASURES Description and analysis of x-ray changes. METHODS Based on the correction angle of their LL and incorporating PI, the patients were divided into 5 groups using the Schwab classification. Clinical and radiologic parameters were analyzed: Group 1 was 10 RESULTS The groups that showed 80% or more optimal sagittal alignment at their postoperative (Post) and the last follow-up (Last), were group 3, 4, and 5. Post and Last thoracic kyphosis (TK) were increased naturally. Post PT was decreased, but group 1 and 2 did not meet Schwab's target value, and the Post and Last PTr showed a tendency to decrease from group 1 to group 5 as LL increased. Based on correlation test with Post SVA, TK correction and SVA correction, Post lumbosacral angle, Post LL, PI–LL, Post PTr and Post PT were associated. Logistic regression analysis with these correlation factors led to risk factors of Post sagittal imbalance, and after confirming the significance of each path, it was confirmed that the effects of PI–LL and Post PTr were valid (p CONCLUSIONS Our study showed that undercorrection showed unfavorable results for the correction of LDK patients over age 65. Therefore, the restoration of global sagittal balance is more important, and through our study, the risk factors of Post sagittal imbalance were the value of PI–LL and that of PTr, and target value of PI-LL was FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.