Date of Award


Degree Type

Selective Evidence-Based Medicine Review

Degree Name

Master of Science in Health Sciences - Physician Assistant


Physician Assistant Studies


OBJECTIVE: The objective of this selective EBM review is to determine whether or not lowlevel laser therapy is effective for pain reduction in patients with chronic low back pain.

STUDY DESIGN: Two randomized controlled trials published in 2010 and 2017 and one nonrandomized placebo-controlled clinical trial published in 2018.

DATA SOURCES: Sources were written in English and published in peer-reviewed journal articles comparing low-level laser therapy (LLLT) to groups consisting of a combined laser therapy regimen or placebo in patients with chronic low back pain, found using PubMed.

OUTCOMES MEASURED: Low back pain was assessed using the visual analog scale (VAS). The statistics used to assess significance of the outcome measured were P-values, change in mean from baseline, and SD.

RESULTS: The first study (Ay S, Doğan Ş, Evcik D. J Back Musculoskelet Rehabil. 2017;30(2):235-240. doi: 10.3233/BMR-160739) compared two treatment groups who received LLLT for the treatment of chronic low back pain (CLBP). Improvements in pain were statistically significant in both groups (p-value <0.01), but no difference was found between the two LLLT regimens. Another study (Ay S, Doğan Ş, Evcik D. Clin Rheumatol. 2010;29(8):905- 910. doi: 10.1007/s10067-010-1460-0) compared LLLT vs placebo in patients with CLBP, in addition to analyzing LLLT vs placebo in acute pain management. A statistically significant improvement in pain severity (p-value <0.001) was observed in LLLT and placebo groups for CLBP. A third study (Taradaj J, Rajfur K, Shay B, et al. Clin Interv Aging. 2018;13:1445- 1455. doi: 10.2147/CIA.S168094) again compared LLLT to placebo for CLBP, in addition to analyzing high-intensity laser therapy (HILT) to placebo. In the LLLT and LLLT sham groups, a statistically significant (p<0.01) decrease in pain was noted.

CONCLUSION: These results superficially indicate that LLLT is an effective means of reducing pain associated with CLBP. However, comparison between sham groups and actual treatment groups seem to suggest a significant influence of placebo in the efficacy of LLLT. This evidence suggests that the general experience of undergoing laser therapy is what causes a reduction of pain, rather than science behind the laser therapy itself. The evidence provided is therefore not sufficient enough to support the claim that LLLT is an effective, appropriate or advisable treatment of CLBP. Future studies should directly compare the statistical difference in decreased pain scores between LLLT and placebo alone.