Tomographic Study of the S2-Alar-Iliac Screw Technique in Brazilian Men

Abstract

Objective The use of pedicle screws was a milestone for modern spinal surgery. This type of fixation, due to its superior biomechanics, gave greater fixation power, greater capacity to withstand the pulling forces and, therefore, greater stability and lower rates of pseudoarthrosis. Fixation of the lumbosacral junction, even with the development of these new implants, remains a challenge mainly because the considerable rates of pseudoarthrosis. The use of iliac screws solves the biomechanical difficulties. However, its use shows high rates of surgical wound problems. The S2-Alar-Iliac screw (S2AI) came as a solution to these complications. The lack of studies about anatomical and anthropometric parameters in the Brazilian population justifies the study. Methods Eleven hip tomographies of Brazilian adult males were analyzed by four evaluators. The right and left sides were considered. In each patient, measurements were made of greater and shorter bone length, greater and smaller bone diameter, distance from the entry point to the skin, sagittal and axial angles related to the hypothetical insertion of an S2AI screw and compared to the same measurements obtained with the iliac screw. Results The mean bone length was 136.7 mm, the greatest bone diameter was 24.8 mm, the smallest bone diameter was 19.7 mm and the distance from the screw to the skin was 42.1 mm for the S2AI screw. Conclusions The obtained data present an average of the sample that can be useful in the decision of the surgical technique in the studied group. Level of evidence I; Diagnostic Studies (Anatomical Investigation).