Standing lateral lumbar spine and pelvis (SLLP) radiograph: a screening, reduced radiation method, for sagittal imbalance

Introduction: Sagittal imbalance is a predictor of failure after surgery for lumbar degenerative pathology. For this reason, specialists advocate correction of sagittal deformity and systematically perform preoperative standing whole spine films. Such diagnostic investigations expose patients to significant doses of radiation. The authors propose an easier radiographic investigation helpful as a screening test to identify patients likely to have sagittal imbalance. Methods: Fifteen whole spine lateral films were evaluated, classifying subjects into three categories: balanced, compensating imbalanced or imbalanced. A second specialist evaluated the reduced SLLP versions of the film (from L1 to proximal femora), measuring spinopelvic parameters. Results: In the SLLP film, the combination of two parameters (femoral inclination >10°, pelvic tilt >1/3 pelvic incidence +5°) identified 94 % of patients with altered sagittal balance. Conclusions: This study preliminarily suggests that the SLLP film can be a useful screening test for sagittal balance abnormalities.