There is a high probability that you, or someone you know, is currently suﬀering from “back pain “. More than likely it is low back pain, as it aﬀects nearly two thirds of the population at some point during their lifetime. Low back pain is the ﬁfth most common symptom for which patients visit physician and is the ﬁrst for which patient visit chiropractors.
Due to this high prevalence, low back pain has an enormous associated health care cost estimated at 26.3 billion in the US in 1998 (Luo et al., 2004). The news is not all bad, as the majority of low back pain cases typically improve rapidly in the ﬁrst month (Pengal et al., 2003).
Up to one third of patients however report persistent back pain of at least moderate intensity one year following an acute episode and 1 in 5 report substantial limitations in activity. These statistics indicate that 5% of people with back pain account for 75% of health care cost. Lumbar disc herniation account for only 4% of low back pain patients but account for a high percentage of low back pain costs. A painful disc herniation results when a tear allows the migration of the nucleus pulposus (protrusion), causing nerve root compression or irritation.
Lumbar disc herniations typically occur in individuals between 30-40 years group, when the nucleus pulposus is still ﬂuid and the annulus is weakened by activity and age. Due to this relatively young demographic, poor treatment outcomes can result in decades of suﬀering for these patients. Clinical guidelines have been implemented by the medical and chiropractic community amongst others to assist practitioners in the diagnosis and treatment of low back pain.
The major problem in the diagnosis is that back pain problems are seldom simple and are often complex with associated altered biomechanical aﬀectations. Treatment can be even more problematic as there are a multitude of treatment options ranging from surgery to bed rest. Although the evidence shows that the majority of disc herniation with radiculopathy (leg pain) improve within the ﬁrst 4-weeks with noninvasive management, and that the majority of these cases will go unnoticed and will heal through natural processes, for those cases that do not heal, there is very little that modern medicine oﬀers to resolve this pathology.
Surgical discectomy should be the last option as the eﬀectiveness of this technique does not appear to be superior to the conservative management. Although noninvasive therapies such as low level laser therapy have not been shown to be eﬀective for either chronic and acute low back pain by some studies (Chou and Huﬀman, 2007), as more researchers are getting involved with laser applications, recent publications are beginning to demonstrate the eﬀectiveness of laser therapy for the treatment of these patients.
Prior to the existence of imaging studies, little was known about the healing mechanisms of disc herniation. Imaging studies have conﬁrmed what has been long suspected that disc herniation can decrease in size and even disappear spontaneously, leading to decreased pressure on the nerve root. In an adult disc, blood vessels are normally restricted to supplying only the outer layers of the annulus. Low oxygen tension at the center of the disc leads to an anaerobic metabolism, resulting in high concentration of lactic acid and a low pH. These deﬁciencies in metabolite transport, limit both the density and the metabolite activity of disc cells. Collagen turnover time in articular cartilage is approximately 100 years and is theorized to be even lower in disc.
The result is that intervertebral discs have a limited ability to recover from metabolic and mechanical injuries such as herniations. There have been a number of mechanisms investigated how disc herniations heal, although it is generally accepted that the herniated fragments are reabsorbed along with the proliferation of granulation tissue with abundant vascularization surrounding the ﬁbrocartilagenous fragments. Within the granulation tissue, the prevailing cell types are macrophages and endothelial cells. These cell types have been demonstrated to be positively aﬀected by laser therapy.
The stimulation of macrophages and ﬁbroblasts is suspected as being the primary mechanism by which laser therapy helps in the healing of disc herniations (Young et al., 1989). Inﬂammatory markers are also present at the site of disc herniations leading to higher prostaglandin E2 concentration. Two recent studies have demonstrated that laser therapy is eﬀective in reducing the prostaglandin E2 concentration (Lim et al., 2007, Bjordal et al., 2005). The reduction in inﬂammation appears to be another method by which laser therapy promotes healing in disc herniations.
With the review of the empirical evidence, although laser therapy has still not been shown conclusively as an eﬀective tool against discal pathology, new and better design studies are suggesting an increased eﬀectiveness towards this at time disabling entity. Consequently, laser therapy is increasingly considered a viable option in the relief of back pain associated with discal pathologies.