Comparison of trunk stiffness provided by different design characteristics of lumbosacral orthoses
Received 2 May 2009; accepted 20 October 2009. published online 10 December 2009.
Abstract
Background
Lumbosacral orthoses (LSOs) are class I medical devices that are used in conservative and postoperative management of low back pain. The effectiveness of LSOs depends on their design aimed at enhancing trunk stiffness. Therefore, the purpose of this study was to compare two lumbar supports: extensible (made of neoprene and lycra) and non-extensible (made of polyester and nylon).
Methods
Trunk stiffness and damping was estimated from trunk displacement data in response to a quick force release in trunk flexion, extension, and lateral bending. Fourteen male and 6 female subjects performed five trials at each experimental condition: (1) No LSO, (2) extensible LSO, (3) non-extensible LSO, (4) non-extensible LSO with a small rigid front panel, and (5) non-extensible LSO with a large rigid front panel. Testing order was randomized and the LSOs were cinched to a pressure of 70mmHg (9.4kPa) measured between posterior aspect of the iliac crest and the orthosis.
Findings
The non-extensible LSO reduced trunk displacement by 14% and increased trunk stiffness by 14% (P<0.001). The extensible LSO did not result in any significant change in trunk displacement or stiffness. The addition of rigid front panels to the non-extensible LSO did not improve its effectiveness. The trunk damping did not differ between the LSO conditions.
Interpretation
A non-extensible LSO is more effective in augmenting trunk stiffness and limiting trunk motion following a perturbation than an extensible LSO. The rigid front panels do not provide any additional trunk stiffness most likely due to incongruence created between the body and a brace.
aMichigan State University Center for Orthopedic Research, Department of Surgical Specialties, College of Osteopathic Medicine, Ingham Regional Orthopedic Hospital, 2727 S, Pennsylvania Avenue, Lansing, MI 48910, USA
bDivision of Physical Therapy, College of Health Professions, Medical University of South Carolina, Charleston, SC, USA
ABSTRACT