The effect of lumbosacral orthosis on the thickness of deep trunk muscles using ultrasound imaging: A randomized controlled trial in patients with chronic low back pain

OBJECTIVE: This study was conducted to evaluate the changes occurring in the thickness of deep trunk muscles, measured using ultrasound imaging, after 4 wks of lumbosacral orthosis use in conjunction with routine physical therapy. DESIGN: This parallel-group, randomized, controlled trial was conducted on 44 patients with nonspecific chronic low back pain, randomly allocated to the experimental and control groups. Both groups received eight sessions of physical therapy twice per week for 4 wks. The experimental group wore nonextensible lumbosacral orthosis, in addition to undergoing routine physical therapy. The thickness of the transversus abdominis, obliquus internus, and lumbar multifidus was measured by ultrasound before and after the 4-wk intervention. RESULTS: The deep trunk muscles differed in thickness in various test positions. Four weeks of intervention with lumbosacral orthosis and routine physical therapy, however, did not change the thickness of the obliquus internus, transversus abdominis, and lumbar multifidus. CONCLUSIONS: Wearing lumbosacral orthosis for an average of 7.21 hrs/d for 4 wks in conjunction with routine physical therapy did not affect the thickness of obliquus internus, transversus abdominis, and lumbar multifidus.