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Proximal junctional kyphosis (PJK) is one of the most common complications following adult spinal deformity (ASD) surgery and has been intensively studied over the last decade. This study aims to investigate the evolution of PJK rate over a 10-year enrollment period within a prospective database of ASD patients. The hypothesis is that the rate of PJK and PJF will decrease across time. Retrospective review of prospective multicenter database. A total of 641 ASD patients with minimum 2-year follow-up. Rate of PJK and PJF. ASD patients with a fusion extended to pelvis and a minimum of 2-year follow-up were included. To investigate a continuous evolution of the PJK/PJF rate, a moving average of 321 patients was calculated across the entire enrollment period, allowing for 95% CI on rate for an incidence of 30% or less. Radiographic PJK was defined as a PJA>10° at 2Y and ΔPJA>10° between preoperative and 2-year follow-up. PJF was defined as either revised for PJK before 2-year visit or Severe radiographic PJK at 2-year follow-up (PJA>28° & ΔPJA>22°). Logistic regression was used to investigate association between date of surgery and PJK and/or PJF. Comparison of PJK rate, demographics and surgical strategies was performed between the first and second half of the cohort. A total of 641 patients met inclusion criteria (age: 64±10yo, 78.4% F, BMI: 28.3±5.7). The overall rate of radiographic PJK at 2-year was 48.2% (N=309/641); 12.9% (N=83/641) of the patients developed a PJF, with 31.3% (N=26/83) being revised within 2-year. The stratification by date of surgery (DOS) yielded 2 timeframes: First= Oct 2008 to Jul 2014 (with a median DOS of Sep 2011), and Second=Jun 2014 to Apr 2018 (with a median DOS of Aug 2016). Between these 2 periods, the rate of radiographic PJK demonstrated a nonsignificant decrease from 50.3% to 45.5% (p=0.22) and PJF from 15.0% to 10.9% (p=0.12). Linear interpolation of the rate of PJK and PJF by enrollment using a moving average suggested a decrease of 1.1% PJK per year and 1.0% PJF per year. Over the study period, patients became continuously older (from 62.6±10.3 to 65.5±8.7 p<0.001) and were more likely be classified as a pure sagittal deformity (SRS Type N from 31.2% to 47.4% p<0.001). Across the enrollment period, there was a shift in surgical strategy, with a significant reduction of 3CO use (35.1% vs 20.8% p<0.001), an increase in ALL release (0% vs 18.4% p<0.001), a decrease in the number of levels fused (12.2±3.5 vs 11.7±3.9 p=0.016), and an increase in the use of PJK prophylaxis (31.3% vs 55.1%). Logistical regression analysis demonstrated no significant association between date of surgery and radiographic PJK (p=0.19) or PJF (p=0.39). Despite extensive research examining risk factors for PJK/PJF and increasing utilization of intraoperative PJK prophylaxis techniques, the rate of radiographic PJK and/or PJF did not significantly decrease across the 10-year enrollment period of this ASD database. The increase in patient risk factors (older) was probably balanced by changes in surgical strategy and preoperative optimization. Continuous enrollment and follow-up will allow ongoing study which may eventually lead to significant decreases in the rate of PJK and PJF. This abstract does not discuss or include any applicable devices or drugs. [ABSTRACT FROM AUTHOR]

The distribution of lumbar lordosis (LL) between L1-4 and L4-S1 is known to vary based on pelvic incidence (PI). However, the extent to which regional changes effect pelvic tilt (PT) is not clearly elucidated. This information can be useful for adult spinal deformity (ASD) surgical planning. To investigate the change in pelvic tilt (PT) imparted by regional changes in LL at 2-year minimum follow-up. Retrospective study of a multicenter ASD database. A total of 103 ASD patients. Radiographic parameters. Operative patients from a multicenter ASD database were included with LIV S1/Ilium, >5 levels of fusion, PJK angle <20 and >5° of change from L4-S1 and L1-4. Patients with PJK angles >20 were excluded due to the compensatory effect this has on PT. Radiographic analysis was performed evaluating thoracic kyphosis (TK), T10-L2 (TL), L1-S1 (LL), L4-S1, L1-4, SVA and PI-LL from pre- to postoperative and change at 2-year follow-up. Paired t-tests were utilized to analyze the change in parameters and HRQOLs at 2-year follow up. Stepwise regression analysis was performed in order to determine the relationship between PT and the above radiographic parameters. HRQOLs (ODI, PCS, MCS, SRS-22r) were also compared between pre- and postoperative timepoints at 2 years. A total 103 patients met inclusion for the study. Paired t-tests demonstrated improvements in all the radiographic parameters (TK 30.1 vs 49.8, SVA 122 vs 28, LL 19.4 vs 51.9, PI-LL 35.2 vs 3.2, p<0.01) and HRQOLs at 2 year follow up respectively (ODI 47.9 vs 28.1, PCS 28.0 vs 39.9, MCS 45.9 vs 51.5, SRS-22r 2.6 vs 3.7, p<0.01). TL was not significantly different at 2 years (11.2 vs 8.6, p=0.14). Stepwise regression model showed an inverse relationship between PT and LL change (r=0.71, p<0.01). Regionally, an increase in 10° from L4-S1 correlated with a 2.4° decrease in PT (p<0.01), while an increase in 10° from L1-4 resulted in a 1.6° decrease in PT (p<0.01). In the surgical planning for ASD, our data demonstrated significant correlational difference between corrections in the upper (L1-4) and lower (L4-S1) lumbar spine and PT changes. These calculations can be useful in planning sagittal plane corrections for ASD and are analogous to prior literature on alignment changes after 3CO in the lumbar spine. This abstract does not discuss or include any applicable devices or drugs. [ABSTRACT FROM AUTHOR]