LUMBAR LORDOSIS VARIATION ACCORDING THE TYPE OF POSITIONER USED IN LUMBAR ARTHRODESIS

ABSTRACT Objective: Evaluate the influence of the most used surgical positioners for lumbar lordosis (LL) in asymptomatic individuals. Methods: Cross-sectional study based on demographic data and radiographic parameters of asymptomatic individuals. For this study, 16 volunteers, 15 males, and one female were selected, and the average age was 24.6 years. They were submitted to lateral radiographs of the lumbar spine in orthostasis in use of the following positioners: gel cushion, gel cushion with hip extension, four-point Relton-Hall and Wilson-type positioner. Results: The mean LL in the orthostatic position was 58.76º, whereas in the gel cushion positioner it was 52.51; on the gel cushion with hip extension of 58.23º, Relton-Hall/4points 37.63º and, finally, on the Wilson-type positioner of 40.87º. An average reduction of 5.42º of the LL was observed when positioning on the gel cushion in relation to the orthostasis. In the linear regression analysis, the data presented statistically significant results (p<0.05), demonstrating that the L4-S1 segment influences 60% in LL. Conclusion: The positioner with gel cushion and hip extension reproduces an LL similar to physiological values. Relton-Hall and Wilson-type positioners with hip flexion promote hypolordotic positioning compared to basal lordosis in orthostasis. Hip extension alone generated a 5.96º increase in the subject’s lordosis. The L4-S1 segment has a 60% influence on the LL when the individuals are in the positioners. Level of evidence III; Controlled cross-sectional study.