The efficacy of laser therapy in wound repair: a meta-analysis of the literature.
OBJECTIVE
We determined the overall effects of laser therapy on tissue healing by aggregating the literature and subjecting studies meeting the inclusion and exclusion criteria to statistical meta-analysis.


BACKGROUND
Low-level laser therapy (LLLT) devices have been in use since the mid sixties, but their therapeutic value remains doubtful, as the literature seems replete with conflicting findings.


METHODS
Pertinent original research papers were gathered from library sources, online databases and secondary sources. The papers were screened and coded; those meeting every inclusion and exclusion criterion were subjected to meta-analysis, using Cohen's d. statistic to determine the treatment effect size of each study.


RESULTS
Twenty-four studies with 31 effect sizes met the stringent inclusion and exclusion criteria. The overall mean effect of laser therapy on wound healing was highly significant (d = +2.22). Sub-analyses of the data revealed significant positive effects on wound healing in animal experiments (d = +1.97) as well as human clinical studies (d = +0.54). The analysis further revealed significant positive effects on specific indices of healing, for example, acceleration of inflammation (d = +4.45); augmentation of collagen synthesis (d = +1.80); increased tensile strength (d = +2.37), reduced healing time (d = +3.24); and diminution of wound size (d = +0.55). The Fail-Safe number associated with the overall effect of laser therapy was 509; a high number representing the number of additional studies-in which laser therapy has negative or no effect on wound healing-required to negate the overall large effect size of +2.22. The corresponding Fail-Safe number for clinical studies was 22.


CONCLUSIONS
We conclude that laser therapy is an effective tool for promoting wound repair.
Woodruff
Lynda D
LD
Department of Physical Therapy, North Georgia College and State University, Dahlonega, Georgia, USA.
Bounkeo
Julie M
JM
Brannon
Windy M
WM
Dawes
Kenneth S
KS
Barham
Cameron D
CD
Waddell
Donna L
DL
Enwemeka
Chukuka S
CS
D000818:Animals; D006801:Humans; D028022:Low-Level Light Therapy / Q000379:methods*; D016896:Treatment Outcome; D014945:Wound Healing / Q000528:radiation effects*