ORIGINAL ARTICLE Short-term therapeutic effects of 890-nanometer light therapy for chronic low back pain: a double-blind randomized placebo-controlled study Ru-Lan Hsieh & Wen-Chung Lee Received: 11 January 2013 / Accepted: 18 June 2013 / Published online: 3 July 2013 # Springer-Verlag London 2013 Abstract We conducted a double-blind randomized placebo- controlled study to investigate the effects of short-term 890- nm light therapy in patients with chronic low back pain in a rehabilitation clinic. Thirty-eight women and 22 men with chronic low back pain (mean age, 60.3 years; range, 32– 80 years) received 40-min sessions of hot-pack therapy combined with active or placebo 890-nm light therapy (wavelength=890 nm, radiant power output=6.24 W, power density=34.7 mW/cm 2 for 40 min, total energy=83.2 J/cm 2 ) over the lower back three times weekly for 2 weeks. Partici- pants were assessed before and after treatment by using a range of motion measurements, a visual analog scale evalua- tion of pain, the Multidimensional Fatigue Inventory, the Biodex Stability System, the Fear-Avoidance Beliefs Ques- tionnaire, repeated chair-rising times, the Frenchay Activity Index, the Oswestry Disability Questionnaire (ODQ), and the Osteoarthritis Quality of Life Questionnaire. The severity of disability based on the ODQ score was used as the primary clinical outcome measurement. Compared to the baseline measurements, participants in the treatment group reported significant reductions in fear-avoidance beliefs regarding physical activity (P=0.040) and work (P=0.007) and in the severity of disability (P=0.021). Treatment with hot-pack therapy and 890-nm light therapy was associated with reductions in the severity of disability and fear avoidance beliefs in patients with chronic low back pain. Keywords Low back pain . Light therapy . Effects . Fear-avoidance . Disability Introduction Low back pain affects 60 to 80 % of adults during their lifetime, and is one of the most prevalent ailments in society [1]. Low back pain causes activity limitations and disability, and imposes a substantial financial burden on patients and health care systems [2], the majority of which stems from patients’ disabilities, rather than treatment costs [3]. Al- though most patients with low back pain recover spontane- ously within 1 to 3 months, regardless of the treatment or treatment type, 3 to 10 % develop chronic low back pain [4]. The etiology and underlying pathology of low back pain are often unclear, and may be multifactorial [5]. The psycholog- ical, occupational, and social impacts of chronic low back pain increase with the duration or severity of the condition [6]. Low back pain is a multifaceted phenomenon that causes psychological distress, physical impairment, and social lim- itations [7]. According to the International Classification of Functioning, Disability and Health (ICF), a functional health status consists of dynamic biopsychosocial interactions among the components of body functions and structures, activities, participation, and personal and environmental factors [8]. Therefore, the major goal in the management of low back pain is to enable patients to resume their daily activities and main- tain an optimal functional health status [8, 9]. Physical modalities are common treatments for musculo- skeletal disorders to ameliorate pain and improve functional performance. Light energy exerts biochemical, bioelectrical, bioenergetic, and biostimulatory effects [10]. Mechanisms by which light therapies have been shown to relieve pain R.<L. Hsieh (*) Department of Physical Medicine and Rehabilitation, Shin Kong Wu Ho-Su Memorial Hospital, 95 Wen Chang Rd, Shih-Lin District Taipei 11101, Taiwan e-mail: M001052@ms.skh.org.tw R.<L. Hsieh School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan W.<C. Lee Institute of Epidemiology and Preventive Medicine, College of Public Health, National Taiwan University, Taipei, Taiwan Lasers Med Sci (2014) 29:671–679 DOI 10.1007/s10103-013-1378-2