A non-invasive, cold form of laser treatment can help people suffering from chronic neck pain, a condition that affects up to one person in four, a study published online by The Lancet said on Friday.
So-called low-level laser therapy (LLLT) entails using a laser's light - but not its fiercely concentrated heat - to stimulate tissue repair and ease pain.
Doctors led by Roberta Chow of the Brain and Mind Research Institute at Australia's University of Sydney carried out an overview of 16 randomised trials that put this increasingly popular procedure to the test.
A total of 820 patients were enrolled in the trials, divided into groups that received either the therapy or a lookalike, dummy treatment.
In five trials, patients given LLLT were around four times likelier to have reduced pain compared with a placebo, the paper found.
In the 11 other trials, for which there was a detailed analysis of pain symptoms, LLLT patients reported reductions of chronic pain by around 20 points on a scale of 100 points. The pain reduction continued for up to 22 weeks.
LLLT compares favourably with other drugs and other remedies for effectiveness and its side-effects are mild, says the study, which recommends that it be used in combination with an exercise programme.
Why LLLT works, though, is unclear. The authors suggest it could interfere with pathways of inflammation, muscle tiredness and the transmission of pain signals along nerves.
Between 10 and 24 percent of people suffer from chronic neck pain, inflicting a cost running into the hundreds of millions of dollars and highlighting the need for simple but effective treatent, the authors said.