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What is Laser Therapy?

History of Laser Therapy

What Health Problems Benefit from Laser Therapy?

How Does It Work?

Biological Effects of Laser Therapy

How Does High Power Laser Therapy Compare with "Cold Laser" Therapy?

Research Studies on Laser Therapy

 

NEUROPATHY / NERVE PAIN RESEARCH STUDIES

LASER IRRADIATION ABATES NEURONAL RESPONSES TO NOCICEPTIVE STIMULATION OF RAT-PAW SKIN.

Brain Res Bull. 1994; 34 (4): 369-374.
Tsuchiya K; Kawatani M; Takeshige C; Matsumoto

The effects of diode laser irradiation on peripheral nerves was examined by monitoring neuronal discharges elicited by application of various stimuli to the hind-paw skin of rats.

Neuronal discharges elicited by brush, pinch, cold, and/or heat stimulation, as well as chemical stimulation by injection of turpentine (0.1 ml, SC) were recorded from L5 dorsal roots in urethane-anaesthetised rats. Diode laser irradiation (830 nm, 40 mW, 3 min, continuous wave) of the saphenous nerve exposed from the muscle of the lower leg significantly inhibited neuronal discharges elicited by pinch (68.4 +/- 6.5%), cold (45.4 +/- 9.2%), and heat stimulation (49.2 +/- 11.3%). Neuronal discharges induced by brush stimulation (104.3 +/- 4.7%) were not affected by laser irradiation. Injection of turpentine, a chemical irritant, into the hind-paw skin (0.1 ml, SC) elicited neuronal discharges in the ipsilateral dorsal root, and these discharges were significantly inhibited or abolished by laser irradiation. In 6- to 7-week-old rats treated neonatally with capsaicin (10 mg/kg, SC), injection of turpentine into the hind-paw skin did not elicit neuronal discharges and laser irradiation did not affect the background discharges. These data suggest that laser irradiation may selectively inhibit nociceptive neuronal activities.

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CRANIAL IRRADIATION WITH GAALAS LASER LEADS TO NALOXONE REVERSIBLE ANALGESIA IN RATS.

Psychol Rep. 1996; 78 (3): 727-731.
Wedlock P M; Shephard R A.

Laser irradiation of the rat cranium can produce analgesia. The present experiment investigated the mechanism of such action. 27 rats received all possible combinations of laser (0, 6.4, and 12J/cm2) and naloxone (0, 5, and 10 mg/kg) prior to a hot plate test.

Laser (820 nm, 1000 Hz pulsing, was applied to the rats' skulls and hind paw lick latencies (in seconds) were recorded immediately, 30 min., and 24 hr. after the administration of treatment. When animals were tested immediately following laser irradiation at 12J/cm2 significant analgesia resulted. Treatment with naloxone at either dose antagonised this effect, but naloxone produced no significant hyperalgesia when given alone. This suggests that opioid peptide mechanisms mediate the analgesic action of low-intensity laser irradiation of the cranium.

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CAN LOW REACTIVE-LEVEL LASER THERAPY (LLLT) BE USED IN THE TREATMENT OF NEUROGENIC FACIAL PAIN? A DOUBLE-BLIND, PLACEBO CONTROLLED INVESTIGATION OF PATIENTS WITH TRIGEMINAL NEURALGIA

Laser Therapy, 1996:: 8: 247-252
ArneEckerdal and and Lehmann Bastian
Department of Oral and Maxillofacial Surgery and Oral Medicine,
Odense University Hospital, Denmark

Neurogenic facial pain has been one of the more difficult conditions to treat, but the introduction of laser therapy now permits a residual group of patients hitherto untreatable to achieve a life free from or with less pain. The present investigation was designed as a doubleblind, placebo controlled study to determine whether low reactive-level laser therapy (LLLT) is effective for the treatment of trigeminal neuralgia. Two groups of patients (14 and 16) were treated with two probes. Neither the patients nor the dental surgeon were aware of which was the laser probe until the investigation had been completed. Each patient was treated weekly for five weeks. The results demonstrate that of 16 patients treated with the laser probe, 10 were free from pain after completing treatment and 2 had noticeably less pain, while in 4 there was little or no change. After a one year follow-up, 6 patients were still entirely free from pain. In the group treated with the placebo system, i.e. the non-laser probe, one was free from pain, 4 had less pain, and the remaining 9 patients had little or no recovery. After one year only one patient was still completely free from pain. The use of analgesics was recorded and the figures confirmed the fact that LLLT is effective in the treatment of trigeminal neuralgia. It is concluded that the present study clearly shows that LLLT treatment, given as described, is an effective method and an excellent supplement to conventional therapies used in the treatment of trigeminal neuralgia.

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EFFICACY OF LOW REACTIVE-LEVEL LASER THERAPY (LLLT) FOR PAIN ATTENUATION OF POSTHERPETIC NEURALGIA

Osamu Kemmotsu, Kenichi Sato, Hitoshi Furumido, Koji Harada, Chizuko Takigawa, Sigeo Kaseno, Sho Yokota, Yukari Hanaoka and Takeyasu Yamamura
Department of Anaesthesiology, Hokkaido University School of Medicine, N-15, W-7, Kita-ku, Sapporo 060, Japan
The efficacy of low reactive-level laser therapy (LLLT) for pain attenuation in patients with postherpetic neuralgia (PHN) was evaluated in 63 patients (25 males, 38 females with an average age of 69 years) managed at our pain clinic over the past 4 years. A double blind assessment of LLLT was also performed in 12 PHN patients. The LLLT system is a gallium aluminium arsenide (GaAlAs) diode laser (830 nm, 60 mW continuous wave) Pain scores (PS) were obtained using a linear analog scale (0 to 10) before and after LLLT. The immediate effect after the initial LLLT was very good (PS: 0-3) in 26, and good (PS: 7-4) in 30 patients. The long-term effect at the end of LLLT (the average number of treatments 36 +/- 12) resulted in no pain (PS: 0) in 12 patients and slight pain (PS: 1-4) in 46 patients. No complications attributable to LLLT occurred. Although a placebo effect was observed, decreases in pain scores and increases of the body surface temperature by LLLT were significantly greater than those that occurred with the placebo treatment. Our results indicate that LLLT is a useful modality for pain attenuation in PHN patients and because LLLT is a non invasive, painless and safe method of therapy, it is well acceptable by patients.

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DOUBLE BLIND CROSSOVER TRIAL OF LOW LEVEL LASER THERAPY (LLLT) IN THE TREATMENT OF POST HERPETIC NEURALGIA

Laser Therapy. 1988; 1: 7.
Kevin C Moore MB ChB FRCA Naru Hira. Parswanath Kramer, Copparam Jayakumar & Toshio Ohshiro
Department of Anaesthesia, The Royal Oldham Hospital,

Post herpetic neuralgia can be an extremely painful condition which in many cases proves resistant lo all the accepted forms of treatment. It is frequently most severe in the elderly and may persist for years with no predictable course. This trial was designed as a double blind assessment of the efficacy of low level laser therapy (LLLT) in the relief of the pain of post herpetic neuralgia with patients acting as their own controls. Admission to the trial was limited to patients with established post herpetic neuralgia of at least six months duration and who had shown little or no response to conventional methods of treatment. Measurements of pain intensity and distribution were noted over a period of eight treatments in two groups of patients each of which received four consecutive laser treatments. The results demonstrate a significant reduction in the pain intensity and distribution following a course of low level laser therapy.

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