Influence of the Shape of Back on the Thoraco-lumbar Fractures

Abstract

Introduction: The surgical management of degenerative and malformative spinal deformities takes into account the pelvic and spinal parameters. This concept is not applied in traumatology. Purpose: To adapt the correction of traumatic kyphosis deformity to the type of backs in function of pelvic incidence and to study the influence of the shape of backs on the localization, the type of fracture, the correction, and the loss at follow-up. Methods: It is a prospective study of 80 patients operated from February 2005 to December 2010. Mean folloupup was 52 months (18-72). Patients were treated by the same surgeon by a posterior osteosynthesis using in situ contouring technique. We evaluated kyphosis deformity according the shape of backs assessed by the value of the pelvic incidence (PI) calculated in lying position. Results: Our patients were classified with low PI (type 1, 2) in 35% of cases and high PI (type 3, 4) in 57% of cases. No significant difference was found in the repartition of fracture levels, type of fracture and the kyphosis deformity. However, the number of patients with good correction and with loss at follow-up was important in high pelvic incidence (p<0.001). Discussion: Neurologic status is not the only point of decision in chirurgical treatment. The kyphosis deformity in trauma is also an important point, but this angle is not always easy to measure. The relationship between deformities with injury level of spine depends on type of backs. A patient with trauma (lying position), pelvic incidence is the only angle which gives an idea about the shape of backs. According to Roussouly's classification, type 1 (long thoracolumbar kyphosis) and type 2 (flat), the correlation at the injury level is not necessary, but for type 3 and 4 (with harmony curvature), the correlation seems logical.