CC BY-NC-ND 4.0 · Rev Bras Ortop (Sao Paulo) 2020; 55(06): 702-707
DOI: 10.1055/s-0040-1713163
Artigo Original
Coluna

Description of the Sacropelvic Parameters Measurement Method for S2-alar iliac Screw Insertion

Article in several languages: português | English
1  Departamento de Biomecânica, Medicina e Reabilitação do Aparelho Locomotor System, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brasil
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1  Departamento de Biomecânica, Medicina e Reabilitação do Aparelho Locomotor System, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brasil
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1  Departamento de Biomecânica, Medicina e Reabilitação do Aparelho Locomotor System, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brasil
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1  Departamento de Biomecânica, Medicina e Reabilitação do Aparelho Locomotor System, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brasil
› Author Affiliations

Abstract

Objective Description of the sacropelvic parameters measurement method for S2-alar iliac (S2AI) screw insertion.

Methods Descriptive study of the method for measuring sacropelvic parameters for the insertion of the S2AI screw using computed tomography (CT). The data evaluated in multiplanar reconstructions were the parameters of the screw trajectory, including length, diameter and angles of the trajectory in the axial and sagittal planes.

Results From the sagittal reconstruction, the axis of the series of axial slices is angled three-dimensionally so that it is possible to visualize the S2 vertebra, the screw entry point, and the anteroinferior iliac spine (AIIS) in the same plane. The entry point is demarcated at the midpoint between the dorsal foramina of S1 and S2. To measure the length of the screw, lines are drawn tangent to the inner and outer cortices of the iliac. The diameter is determined by the shortest distance between the inner and outer iliac faces minus half of the diameter of the screw chosen medially and laterally. The path angle in the axial plane is formed by the anteroposterior midline of the sacrum and the line of the screw length. The craniocaudal inclination angle in relation to the S1 plateau corresponds to the degree of inclination made in the sagittal plane to find the image in which the entry point and the AIIS are seen in the same plane.

Conclusion It was possible to adequately assess, through multiplanar CT reconstructions, the sacropelvic parameters necessary for the safe insertion of the S2AI screw.



Publication History

Received: 24 August 2019

Accepted: 20 February 2020

Publication Date:
22 July 2020 (online)

© 2020. Sociedade Brasileira de Ortopedia e Traumatologia. This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commercial purposes, or adapted, remixed, transformed or built upon. (https://creativecommons.org/licenses/by-nc-nd/4.0/)

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