Volume 8, Issue 1, February 2015, Pages 2–16
Open Access
Review article
Laser Acupuncture for Treating Musculoskeletal Pain: A Systematic Review with Meta-analysis
- Open Access funded by International Pharmacopuncture Institute
- Under a Creative Commons license
Abstract
Laser
acupuncture has been studied extensively over several decades to
establish evidence-based clinical practice. This systematic review aims
to evaluate the effects of laser acupuncture on pain and functional
outcomes when it is used to treat musculoskeletal disorders and to
update existing evidence with data from recent randomized controlled
trials (RCTs). A computer-based literature search of the databases
MEDLINE, AMED, EMBASE, CINAHL, SPORTSDiscus, Cochrane Library, PubMed,
Current Contents Connect, Web of Science, and SCOPUS was used to
identify RCTs comparing between laser acupuncture and control
interventions. A meta-analysis was performed by calculating the
standardized mean differences and 95% confidence intervals, to evaluate
the effect of laser acupuncture on pain and functional outcomes.
Included studies were assessed in terms of their methodological quality
and appropriateness of laser parameters. Forty-nine RCTs met the
inclusion criteria. Two-thirds (31/49) of these studies reported
positive effects, were of high methodological quality, and reported the
dosage adequately. Negative or inconclusive studies commonly failed to
demonstrate these features. For all diagnostic subgroups, positive
effects for both pain and functional outcomes were more consistently
seen at long-term follow-up rather than immediately after treatment.
Moderate-quality evidence supports the effectiveness of laser
acupuncture in managing musculoskeletal pain when applied in an
appropriate treatment dosage; however, the positive effects are seen
only at long-term follow-up and not immediately after the cessation of
treatment.
Keywords
- acupuncture therapy;
- low-level laser therapy;
- pain;
- review
1. Introduction
Musculoskeletal disorders represent a significant cost to the health care system [1].
A recent report estimated that 1.7 billion individuals globally are
affected by various kinds of musculoskeletal problems, and highlighted
the considerable impact of chronic pain and disabilities upon
individuals [2]. Coupled with the increasing risk factors such as obesity, sedentary lifestyles, and aging populations in the modern world [3] and [4], increasing prevalence of musculoskeletal disorders is foreseeable, exacerbating the health care burden.
Recent
research confirms that treatments such as physical therapy,
acupuncture, and massage remain popular with pain sufferers. A survey
conducted in 16 European countries showed that 70% of participants who
suffered from musculoskeletal pain sought other forms of treatment apart
from medication [5]. Acupuncture is one of the most common types of alternative treatments for patients looking for long-term pain management [6],
which is a relatively safe procedure with minimal side effects. Growing
demand for, and provision of, acupuncture services have been seen in
different countries [5], [7] and [8],
resulting an interest in, and rapid development of, acupuncture
research in order to establish a more solid evidence-based practice [9].
Such
research development extends to other forms of acupuncture apart from
the traditional needling method. The use of low-level laser to stimulate
acupuncture points is suggested to be a safer technique due to its
noninvasive nature and its acceptability to people with needle phobia [10].
Laser acupuncture is considered to be an effective alternative to
traditional needling, is useful in patients who are needle phobic, or
can be used at acupuncture points that require complicated application
of the needle [10] and [11].
Ever since laser acupuncture studies were conducted in the 1970s [12] and [13],
researchers have focused on the underlying mechanism of laser
acupuncture to build the scientific basis for clinical practice.
Controversy remains concerning the mechanisms of laser acupuncture,
which, being free from any mechanical stimulation, do not share similar
pain modulation pathways to those of traditional needling acupuncture [10].
Rather than producing a “needling sensation,” the acupuncture point
irradiated by the laser needs to receive sufficient energy to elicit the
physiological effect at the cellular level, based upon the wider
principle of “photobiomodulation” [14], [15] and [16].
A key point to determine the effectiveness of laser acupuncture is the
dosage applied: this issue has been stressed in several recent papers [16] and [17].
The development of dosage guidelines for laser acupuncture is
confounded by the lack of a clear understanding of the mechanisms
underpinning such treatment, as dosage dependency is normally explored
during the stage of in vitro and animal studies [10].
At present, the World Association for Laser Therapy guidelines for
low-level laser therapy published in 2010 provide recommendations for
general laser treatment for different conditions only; no specific
guidelines have been developed for laser acupuncture [18] and [19].
Hence, selection of laser parameters and dosage is often subjective or
based on clinical experience. Studies may involve the use of an
inappropriate dosage or report the parameters inadequately; hence, the
results of these studies would be difficult to replicate or provide data
to formulate the most efficacious dose [20], [21] and [22].
More recent evidence supports the physiological effects of laser acupuncture, including anti-inflammatory [23] and antinociceptive effects [24].
Such studies highlight the potential effect of laser acupuncture under
well-controlled conditions; however, whether or not these results can be
extrapolated to the clinical setting remains unclear. It is critically
important to understand the relevance of laser irradiation parameters,
together with the appropriate selection of acupoints, to the
effectiveness of laser acupuncture for musculoskeletal conditions.
Despite
the growth of evidence in the field of laser acupuncture, its
effectiveness for musculoskeletal condition remains unclear because of
inconclusive results from different studies [14], [20] and [22].
This expansion may suggest a shift in the evidence base; therefore, it
is timely to review the results from recent studies to confirm the
current evidence base for laser acupuncture. A systematic review with
meta-analysis was, therefore, conducted to update the previous review in
this area [17],
with the following aims: (a) to assess the clinical effectiveness of
laser acupuncture for relieving pain and improving functional outcomes
when used for treating musculoskeletal conditions; (b) to explore the
relationship between parameter choice and outcomes; and (c) to establish
the level of evidence of the effectiveness of laser acupuncture with an
update of the current literature.
