Dynamic changes in seating pressure gradient in wheelchair users with spinal cord injury

Area of Science:

• Biomedical Engineering
• Rehabilitation Engineering
• Clinical Biomechanics

Background:

• Pressure ulcers are a significant concern for wheelchair users, often assessed using peak pressure gradients (PPGs).
• Altering PPG magnitudes is known to reduce pressure ulcer risk by affecting tissue deformation and perfusion.
• The role of PPG directions in tissue blood flow has been largely overlooked in seating pressure research.

Purpose of the Study:

• To evaluate the impact of combined wheelchair tilt and recline angles on both PPG magnitudes and directions.
• To investigate how these adjustments influence tissue perfusion and deformation in at-risk areas.

Main Methods:

• Thirteen power wheelchair users participated in the study.
• Six combinations of wheelchair tilt (15°, 25°, 35°) and recline (10°, 30°) were tested in random order.
• Measurements of PPG magnitudes and directions under the left ischial tuberosity were recorded during various sitting postures.

Main Results:

• Wheelchair recline was found to be particularly effective in reducing PPG magnitudes.
• Wheelchair tilt demonstrated a notable ability to manipulate PPG directions.
• These findings suggest distinct benefits of tilt and recline for managing seating interface pressures.

Conclusions:

• Combining wheelchair tilt and recline offers a dynamic approach to pressure ulcer prevention.
• Recline primarily mitigates pressure intensity, while tilt influences pressure distribution patterns.
• Understanding and utilizing both PPG components can optimize pressure relief strategies for wheelchair users.