RESUMEN
STUDY DESIGN: A radiographic study of 153 normal volunteers. OBJECTIVES: 1) To test the hypothesis that the vertical projection of the sum of the ground reactive forces of a standing patient is located in the same place in the sagittal plane as the C7 plumb line; 2) to determine if there are consistent geometric relationships between the location of the top of the spine and the pelvis in the sagittal plane that occur in individuals without symptoms of back pain or radiographic evidence of deformity. SUMMARY OF BACKGROUND DATA: Defining the optimal state of spinal balance is difficult. A full understanding of the compensatory relationships between the spine, pelvis, and lower limbs remains elusive. METHODS: A total of 153 normal volunteers were subjected to radiographic examination using a digital force plate, a stabilized standing position, a standardized radiographic technique, and the computerized measurement of sagittal alignment. RESULTS: 1) The C7 plumb line and the gravity line in a stabilized standing position are not located in the same place; 2) the association between the center of T1 and the sacral endplate may be an anatomic constant and a marker of spinal balance in individuals without symptoms of back pain or radiographic evidence of deformity, and is determined by the formula 99 degrees - 0.1 degrees (sacral slope). CONCLUSIONS: We speculate that this information will be very helpful in evaluating symptomatic spinal disease in the context of the overall alignment of the spine and pelvis.
Asunto(s)
Vértebras Lumbares/diagnóstico por imagen , Postura , Sacro/diagnóstico por imagen , Adolescente , Adulto , Estudios de Cohortes , Femenino , Humanos , Vértebras Lumbares/fisiología , Masculino , Persona de Mediana Edad , Pelvis/diagnóstico por imagen , Pelvis/fisiología , Postura/fisiología , Radiografía , Proyectos de Investigación/normas , Sacro/fisiologíaRESUMEN
STUDY DESIGN: A prospective radiographic study of 160 volunteers without symptoms of spinal disease was conducted. OBJECTIVES: The objective of this study was to describe, quantify, and classify common variations in the sagittal alignment of the spine, sacrum, and pelvis. SUMMARY OF BACKGROUND DATA: Previous publications have documented the high degree of variability in the sagittal alignment of the spine. Other studies have suggested that specific changes in alignment and the characteristics of the lumbar lordosis are responsible for degenerative changes and symptomatic back pain. METHODS: In the course of this study, anteroposterior and lateral radiographs of 160 volunteers in a standardized standing position were taken. A custom computer application was used to analyze the alignment of the spine and pelvis on the lateral radiographs. A four-part classification scheme of sagittal morphology was used to classify each patient. RESULTS: Reciprocal relationships between the orientation of the sacrum, the sacral slope, the pelvic incidence, and the characteristics of the lumbar lordosis were evident. The global lordotic curvature, lordosis tilt angle, position of the apex, and number or lordotic vertebrae were determined by the angle of the superior endplate of S1 with respect to the horizontal axis. CONCLUSIONS: Understanding the patterns of variation in sagittal alignment may help to discover the association between spinal balance and the development of degenerative changes in the spine.