Effects of laser acupuncture therapy in pain treatment

Abstract

This thesis presents an investigation of the effectiveness of laser acupuncture. Laser acupuncture has been utilised as an approach for the treatment of pain that combines both traditional Chinese acupuncture and low-level laser therapy since its emergence in 1973. Its effects are not well understood and no standardised clinical protocol has been established. In this study, a diode laser (wavelength 680 nm, mean output power 30 mW) was used to irradiate four acupuncture points located on upper extremities over a 10-day period in order to investigate the effectiveness of laser acupuncture on treating pain. The laser acupuncture was applied daily and treatment lasted for three minutes on each acupuncture point. The median nerve conduction velocity was measured at 30-minute intervals on days one, five, and ten. Specifically, there were two independent experiments. The aim of the first was to study the effects of laser acupuncture on normal subjects. In this experiment, the effects of acupuncture were observed through an investigation of the changes of nerve conduction studies over time on eighteen normal volunteers. Results showed that motor nerve fibre was sensitive to laser acupuncture and there was a significant decrease in the motor conduction velocity after laser acupuncture (p < 0.001). It was also found that laser acupuncture resulted in a significant decrease in sensory nerve conduction velocity 30 minutes after application of laser acupuncture. The second experiment was conducted to investigate the efficacy of laser acupuncture on twelve patients with idiopathic bilateral carpal tunnel syndrome. Carpal tunnel syndrome is a common entrapment neuropathy with pain as the main symptom. Patients were given three sessions of laser acupuncture therapy with at least a week interval between successive sessions. Treatment outcome was quantified by patients' subjective feedback (McGill pain questionnaire, visual analogue scale) and objective measurements including physical examination, a grip-strength test, a pinch-strength test, and nerve conduction studies. A randomised single-blind controlled trial was adopted for the first session. From the second session, both hands of patients received real laser acupuncture treatment. The results, except those of the pinch-strength test and the nerve conduction test, indicated that laser acupuncture could improve patient's condition (p < 0.05) after the first session. It was found that the patient's condition was improved more significantly (p< 0.001) after two or more sessions of laser acupuncture treatment. The results also showed that the amount of increase in motor nerve conduction velocity decreased with time and the sensory nerve conduction velocity increased with time. These results suggested that laser acupuncture could improve the condition of patients with idiopathic carpal tunnel syndrome. Further research is recommended to explore the clinically dominant position of laser acupuncture therapy on treating carpal tunnel syndrome or other diseases according to present therapeutic protocol. More research is also needed for the better understanding of the mechanism of laser acupuncture therapy.