Prospective analysis of sagittal vertical axis (SVA) on lateral spine radiographs using 3 different arm positions.
To examine whether fists-on-clavicles position represents a functional standing position.
Radiographic visualization of spinal and pelvic sagittal morphology is difficult during relaxed standing because of interference from the arms; however, standing with arms forward-flexed results in a negative shift in SVA. The fists-on-clavicles position was proposed to provide a more functional sagittal profile and adequate visualization of the spine. No existing study compares the SVA between the fists-on-clavicle and relaxed standing positions.
The SVA was measured on standing lateral radiographs of 14 healthy subjects using 3 different arm positions: relaxed with arms-at-side, arms forward-flexed to 45° (shoulder flexion [SF]), and fists-on-clavicles.
The mean SVA with relaxed standing was 1.4 ± 1.9 cm. SF produced a significant SVA negative shift (−3.7 ± 2.3 cm, P < 0.001). The fists-on-clavicle position resulted in a reduced but significant SVA negative shift (−2.3 ± 2.1 cm, P < 0.001) compared with relaxed standing.
Although the fists-on-clavicles position was better than SF in reducing the SVA negative shift, a significant negative shift did occur in the fists-on-clavicle position compared with relaxed standing.
The sagittal vertical axis in 14 healthy young male subjects was radiographically evaluated using 3 different arm positions: relaxed standing, shoulder flexion, and fists-on-clavicles. A significant negative shift of the mean sagittal vertical axis from relaxed standing (1.4 cm) was observed in the shoulder flexion (−5.1 cm) and fists-on-clavicles positions (−3.8 cm).
From the Department of Orthopaedic Surgery, Yokohama City University, Kanazawa-ku, Yokohama, Japan.
Acknowledgment date: December 11, 2007. Acceptance date: March 18, 2008.
The manuscript submitted does not contain information about medical device(s)/drug(s).
Institutional and foundation funds were received in support of this work. No benefits in any form have been or will be received from a commercial party related directly or indirectly to the subject of this manuscript.
Supported by a 2007 JSPS grant-in-aid for scientific research (No. 19500480-0001) and 2006 Strategic Research Project (No. 186) of Yokohama City University.
Address correspondence and reprint request to Yoichi Aota, MD, Yokohama City University Hospital, Fukuura 3-9, Kanazawa-ku, Yokohama City, Kanagawa Prefecture, Japan 236-0004; E-mail: firstname.lastname@example.org.