Clasped position for measurement of sagittal spinal alignment

Area of Science:

• Orthopedics
• Radiology
• Spine Surgery

Background:

• Lateral whole-spine radiography is crucial for managing spinal deformities.
• Optimal patient positioning, specifically arm placement, requires further definition for accurate measurements.

Purpose of the Study:

• To evaluate the reliability of a specific arm position (clasped) for lateral whole-spine radiography.
• To assess the effectiveness of this position in measuring sagittal spinal alignment in adults.

Main Methods:

• Prospective study involving 26 adult volunteers and 22 patients with lumbar spinal stenosis.
• Lateral whole-spine radiographs were taken with subjects in a stable, relaxed, standing position with arms clasped in front.
• Key parameters measured included sagittal vertical axis (SVA), lumbar lordotic angle (LLA), pelvic angle (PA), pelvic lordosis angle (PRS1), pelvic tilt (PT), and pelvic incidence (PI).
• Interclass correlation coefficients were used to assess measurement reliability.

Main Results:

• The clasped arm position demonstrated "almost perfect agreement" for intra- and interobserver reliability.
• Sagittal vertical axis (SVA) was slightly positive in volunteers.
• Lumbar lordotic angle (LLA), pelvic angle (PA), pelvic lordosis angle (PRS1), pelvic tilt (PT), and pelvic incidence (PI) were within standard normal ranges.

Conclusions:

• The clasped arm position is a reliable and effective method for measuring sagittal spinal alignment of the lumbar region in adults.
• This standardized positioning can enhance the accuracy and consistency of lateral whole-spine radiography in clinical practice.