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Seeing the light – how the use of lasers is revolutionising clinical care


27 July, 2010  

We tend to think of laser as a surgical technique for correcting myopia or removing tattoos. But new applications are being discovered every month, from diagnostics and wound healing to stimulating heart muscle regrowth

Anu Mäkelä PhD
Dean of Acupuncture
and Bioenergy
Research Institute
Hospital, Oslo

Lasers have become indispensable tools in clinical practice. Most doctors are familiar with surgical laser systems but have less knowledge of the use of lasers for preoperative and  postoperative care, diagnosis and therapy. Surgical laser systems have been widely accepted for surgical procedures and cosmetic care, but they all use the principle of selective photothermolysis, which means getting the right amount of the right wavelength of laser energy to the right tissue to damage or destroy only that tissue, and nothing else. Having so many different laser systems available with overlapping uses means it is sometimes difficult to decide on which equipment is best to use in various cases. Several different lasers – such as the CO2 laser, argon laser, Er:YAG laser, alexandrite laser, Nd:YAG laser, KTP laser, pulsed dye laser and diode laser – are now available for use as a ‘scalpel’ for:

  • Body areas prone to bleeding.
  • Retinal and inner-ear surgery.
  • Removal of benign skin lesions such as moles,warts and keratoses.
  • Cosmetic laser resurfacing for wrinkles.
  • Removal of tattoos.
  • Treatment of leg and facial veins.
  • Hair removal.
  • Prostate operations.
  • Disc operations, and so on.[1–5]

Another less well-documented but equally effective type of laser is the low-level laser, which has been the subject of debate for more than two decades now. This prolonged debate is largely due to the fact that, currently, there is no accepted unified theory to explain the mechanism of low-level laser biostimulation, and this lack of knowledge complicates the evaluation of conflicting reports in the literature.[6–9]

Low-level lasers in wound care and healing
Low-level laser therapy (LLLT) has been utilised in the  treatment of a wide variety of medical problems, and it is perhaps due to this that many find it hard to believe in its usefulness. It has also been noted that different parameters of LLLT give a wide variety of results, where wavelength, power density and treatment time play a significant role.[10–14]
One of the most researched areas of LLLT is wound healing and circulation.15–18 Normal wound healing requires both destructive and reparative processes in controlled balance. Proteases and growth factors play an important role in regulating this balance, and if disrupted in favour of degradation, then delayed healing ensues, which is a trait of chronic wounds.[19,20]
It has been shown that low-level laser irradiation at certain fluences and wavelengths can enhance the release of growth factors and stimulate cell proliferation.[14,20–25] Lasers have been shown to be both stimulatory and inhibitory, whereby overstimulation can inhibit healing, thus giving conflicting  results in various experiments. [24–26,28] It has been shown that low-level irradiation of fibroblasts stimulates the production of basic fibroblast growth factor as well as the transformation of fibroblasts into myofibroblasts. [19,21,25,29] LLLT affects immune cells and acts directly and selectively on the immune system.[30- 32] Stimulation of the immune system means that infected wounds can be cleared more readily.[33-35]
A Finnish-Russian study in 2009 demonstrated that in vitro low-power laser irradiation (ℓ – 660 nm, 19 mW, 17J/mL) of bacterial lipopolysaccharide (LPS) significantly attenuated the LPSinduced microcirculatory disturbances including venular dilatation, leucocyte rolling, adhesion of leucocytes and platelets to venular wall and platelet adherence to ultralarge von Willebrand factor multimers on the endothelial surface.[36]
The use of low-level lasers in wound healing has been shown to speed up the healing of leg ulcers and burn wounds; it has also been shown to improve skin-healing capabilities.[34,37]
Low-level laser irradiation induces wound healing in conditions of reduced microcirculation.[34,37]
Schindl and colleagues investigated the effect of LLLT in patients with diabetic microangiopathy by infrared thermography on skin blood circulation. [38–40]
The effects they and Dyson et al found [20] are  listed below:

  • Increased epithelialisation.
  • Re-establishment of arterial venous and lymph function.
  • Decreased oedema.
  • Pain attenuation.
  • Increased ATP, RNA and DNA synthesis.
  • Increased granulation tissue.
  • Increased neovascularisation.
  • Increased matrix synthesis.
  • Increased fibrinogenesis.
  • Decreased inflammation.
  • Increased cytokines and growth factors.
  • Increased stimulation of immune system.
  • Increased tissue nutrition and oxygenation.
  • Increased wound closure.
  • Increased tensile strength.

Recent developments
Recent developments in laser research have focused more deeply on the cellular effects of light and different wavelengths. Research results of the last five years have presented many interesting new applications of lasers in clinical use. Use of lasers in wound healing and tissue recovery has already become widespread, but their uses in other inflammatory processes, such as joint and autoimmune inflammations, have also produced the expected results.[41,42] During 2009, a total of 62 low-level laser studies were published in high-impact journals such as Nature, Pain, PNAS, Spine, Muscle and Nerve, Stroke, Blood and The Lancet. Also, in Russia, over 90 original laser research articles were published during the year. Another quickly growing area is the use of lasers in photodynamic therapy (PDT) and systemic PDT in the treatment of various types of cancer, skin lesions, psoriasis and autoimmune
inflammatory processes.[42-44]
Most recent research has also focused on the effect of laser light on coagulatory processes.[45-48]  In Russia, lasers have been used for the treatment of disseminated intravascular coagulation, also known as consumptive coagulopathy, with good results. Disseminated intravascular coagulation is a serious side-effect of surgery, anaesthesia, sepsis, blood transfusion, malignancy and pregnancy.  A large clinical two-year study for precise recommendations of laser parameters began at the end of last year. Lasers have also become increasingly important research tools in medicine.[49] In the past five years, considerable progress has been made in medical optical diagnostics, particularly in laser-assisted optical diagnostics of rheumatoid arthritis50 on small joints, soft-tissue injuries,  haematomas[51] and cancer.[52] This has been made possible due to the introduction of multispectral diaphanoscopic transillumination, especially in the near-infrared range, which depends on tissue optical scattering and absorption spectra.

Practice and policy issues
At present, the decision as to when to use lasers for treatment of any specific problem remains mostly at the doctor’s discretion. There are no generally accepted guidelines on when lasers should or should not be used, as in many countries they are still seen as experimental treatment procedures or devices. Safety policies also vary, although at the end of 2007 in Milan a general laser safety policy consensus was reached, which could come into effect in Europe within the next two years. It will require every person using a laser to undergo a laser safety certification. This, however, still does not cover the medical
policy of when to choose to use a laser and which kind. The European Medical Laser Association (EMLA) has started the unification process of various small associations and societies, each offering their own recommendations, to achieve a unified outlook on these issues. EMLA started a programme in 2009 which offers safety training and various training courses in the use of lasers in different fields. These courses are held by approved medical experts and are not product-specific. So far, most training courses are provided by equipment manufacturers and usually do not cover general theory or safety issues thoroughly. EMLA has also collected research and brought together scientists from former Soviet countries to incorporate the vast amount of knowledge from these countries into current European research. In just one year in Russia, 17 doctoral dissertations and 28 master’s thesis dissertations
were made on the clinical use of lasers or on the scientific  background on biological function  of lasers.

Future promise
Considering the increasing amount of good scientific research on the cellular and subcellular effects of light and laser, it would seem that the use of lasers, especially in the diagnostic, presurgical and postsurgical therapeutic fields, as well as in the treatment of more complicated diseases, presents a very  promising capability that is yet to be fully realised. Research into the use of lasers in stem cell differentiation, migration and homing [22,23 27] has already produced promising  results in the regrowth and repair of nervous tissues,[17,53] heart  muscle [54] and other internal organs. This appears to be one of the directions that laser research will be heading in the near future, giving hope to patients with otherwise untreatable  dysfunctions. Systemic PDT, and PDT in general, is also  becoming more widely researched and accepted as one of the treatment methods for cancer. Since, in many cases, laser treatments require a little more time from the doctor, it is more likely that private hospitals and clinics will benefit more from these methods. Although lasers are used routinely in patient treatments in government hospitals in Russia, western hospitals still rarely use them for anything other than surgical procedures or for rehabilitation. With more training of doctors in the wider use of lasers, it will hopefully be possible to see them in all hospitals in the near future.

Five-year forecast
Surgical use of lasers will continue and become more widely used. Diagnostic use of lasers will develop further. More  wavelengths will become available and used more precisely for different applications. Combination treatments with stem cells and lasers will develop further. PDT and systemic PDT will become more common in cancer treatments.

Important events
This year, two European noteworthy events in the laser field will take place. The first is Laser Helsinki 2010 on 20-23 August in Finland, with training courses offered by EMLA. Simultaneous
translation from Russian to English, German, Finnish and back during the congress will break language barriers and will  significantly improve communication between professionals from different countries. Over 100 top Russian specialists are  expected to attend. The second is the German CME WALT congress, 25-28 September, Bergen, Norway (Congress language English).

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