STUDY DESIGN: Retrospective review of a patient cohort through a prospective study. PURPOSE: To determine whether there are correlations between radiographic measurements, including sacral slope (SS) and pelvic incidence (PI), and self-reported clinical outcomes among single-level L5/S1 ProDisc-L patients. OVERVIEW OF LITERATURE: The lumbosacral juncture presents unique biomechanical challenges with respect to artificial disc replacement (ADR) because of its orientation and consequential shear loading. Reports of inferior outcomes at L5/S1 compared to those of the outcomes at the levels above, including increased facet joint pain, suggest a relationship with the sacral inclination at L5/S1. METHODS: Plain standing lateral radiographs of 71 patients (age, 26–65 years) who underwent ADR at L5/S1 for degenerative disc disease were reviewed. SS and PI were measured based on pretreatment and initial follow-up standing films. Patient's average adjusted self assessments included the Oswestry disability index and visual analog scale for pain 2 years after ADR. Correlation coefficients were computed to evaluate relationships between radiographic parameters and clinical outcomes. Analysis of covariance was used to evaluate multivariate relationships among factors, including radiographic parameters, body mass index (BMI), and clinical outcomes. RESULTS: SS and PI values were obtained from 71 patients. The average SS was 33.3° and average PI was 39.9°. At the 24-month follow-up, no significant correlations (p≥0.05) were observed between radiographic parameters and clinical outcomes. BMI, age, and sex did not explain any variability in the relationships between clinical outcomes and SS and PI. CONCLUSIONS: We reviewed a large range of SS angles and found no associations between SS, PI, or BMI and clinical outcomes after ADR at L5/S1. These preliminary results demonstrate that ADR provided maintainence of pain relief and functional improvement for a wide range of SS angles, suggesting that steeper angles are not a contraindication for ADR.
Body Mass Index ; Cohort Studies ; Follow-Up Studies ; Humans ; Incidence ; Prospective Studies ; Retrospective Studies ; Self-Assessment ; Total Disc Replacement* ; Visual Analog Scale ; Zygapophyseal Joint

Background: Neutrophil gelatinase-associated lipocalin (NGAL) and hepcidin-25 are involved in catalytic iron-related kidney injury after cardiac surgery with cardiopulmonary bypass. We explored the predictive value of plasma NGAL, plasma hepcidin-25, and the plasma NGAL:hepcidin-25 ratio for major adverse kidney events (MAKE) after cardiac surgery. Methods: We compared the predictive value of plasma NGAL, hepcidin-25, and plasma NGAL:hepcidin-25 with that of serum creatinine (Cr) and urinary output and protein for primary-endpoint MAKE (acute kidney injury [AKI] stages 2 and 3, persistent AKI > 48 hours, acute dialysis, and in-hospital mortality) and secondary-endpoint AKI in 100 cardiac surgery patients at intensive care unit (ICU) admission. We performed ROC curve, logistic regression, and reclassification analyses. Results: At ICU admission, plasma NGAL, plasma NGAL:hepcidin-25, plasma interleukin-6, and Cr predicted MAKE (area under the ROC curve [AUC]: 0.77, 0.79, 0.74, and 0.74, respectively) and AKI (0.73, 0.89, 0.70, and 0.69). For AKI prediction, plasma NGAL:hepcidin-25 had a higher discriminatory power than Cr (AUC difference 0.26 [95% CI 0.00–0.53]). Urinary output and protein, plasma lactate, C-reactive protein, creatine kinase myocardial band, and brain natriuretic peptide did not predict MAKE or AKI (AUC < 0.70). Only plasma NGAL:hepcidin-25 correctly reclassified patients according to their MAKE and AKI status (category-free net reclassification improvement: 0.82 [95% CI 0.12–1.52], 1.03 [0.29–1.77]). After adjustment to the Cleveland risk score, plasma NGAL:hepcidin-25 ≥ 0.9 independently predicted MAKE (adjusted odds ratio 16.34 [95% CI 1.77–150.49], P = 0.014). Conclusions Plasma NGAL:hepcidin-25 is a promising marker for predicting postoperative MAKE.

BACKGROUND: The ability of urinary biomarkers to complement established clinical risk prediction models for postoperative adverse kidney events is unclear. We assessed the effect of urinary biomarkers linked to suspected pathogenesis of cardiac surgery-induced acute kidney injury (AKI) on the performance of the Cleveland Score, a risk assessment model for postoperative adverse kidney events. METHODS: This pilot study included 100 patients who underwent open-heart surgery. We determined improvements to the Cleveland Score when adding urinary biomarkers measured using clinical laboratory platforms (neutrophil gelatinase-associated lipocalin [NGAL], interleukin-6) and those in the preclinical stage (hepcidin-25, midkine, alpha-1 microglobulin), all sampled immediately post-surgery. The primary endpoint was major adverse kidney events (MAKE), and the secondary endpoint was AKI. We performed ROC curve analysis, assessed baseline model performance (odds ratios [OR], 95% CI), and carried out statistical reclassification analyses to assess model improvement. RESULTS: NGAL (OR [95% CI] per 20 concentration-units wherever applicable): (1.07 [1.01–1.14]), Interleukin-6 (1.51 [1.01–2.26]), midkine (1.01 [1.00–1.02]), 1-hepcidin-25 (1.08 [1.00–1.17]), and NGAL/hepcidin-ratio (2.91 [1.30–6.49]) were independent predictors of MAKE and AKI (1.38 [1.03–1.85], 1.08 [1.01–1.15], 1.01 [1.00–1.02], 1.09 [1.01–1.18], and 3.45 [1.54–7.72]). Category-free net reclassification improvement identified interleukin-6 as a model-improving biomarker for MAKE and NGAL for AKI. However, only NGAL/hepcidin-25 improved model performance for event- and event-free patients for MAKE and AKI. CONCLUSIONS NGAL and interleukin-6 measured immediately post cardiac surgery may complement the Cleveland Score. The combination of biomarkers with hepcidin-25 may further improve diagnostic discrimination.