181
Pain, 43 (1990) 181-185 Elsevier
PAIN 01674
Hypalgesic efficacy of acupuncture on experimental pain in man. Comparison of laser acupuncture and needle acupuncture A. Brockhaus Universiiiits-Nervenklinik, (Received
1 December
and C.E. Elger Epileptologie,
1989, revision received 9 February
Bonn (F.R.G.) 1990, accepted
31 May 1990)
The analgesic effect of acupuncture on cutaneous heat stimuli of 43’C has been evaluated in a controlled Summary experimental study with healthy, informed volunteers. Laser acupuncture was administered to 39 probationers using a hetium-neon laser under double-blind conditions. The point Hegu (L.I.4) and Jianqian (Extra.) on both sides were each irradiated for 1 mm. Forty probationers were needled with stainless steel needles in the point Hegu (L.I.4) on both sides under single-blind conditions. Pam threshold was measured in terms of the time (in msec) that the probationers needed to perceive the cutaneous heat stimulus of 43°C. The painful stimulus was generated by a computer-controlled standardized procedure. The Wilcoxon test was used for the statistical evaluation. Laser acupuncture did not change the pain threshold. Needle acupuncture did, however, increase the pain threshold compared with the initial value (a = 0.1%). The difference compared with the control group, where a placebo point was needled, was also significant (a = SW). This controlled experimental study proves the analgesic effect of needle acupuncture on painful heat stimuli. Laser acupuncture had no effect on pain threshold in this study. Key wordsz Needle
acupuncture;
Laser acupuncture;
Analgesia;
Introduction
Methods
Acupuncture is used worldwide for the treatment of acute and chronic pain [12,20], and yet there are only a few experimental studies under controlled conditions, which prove the analgesic efficacy of acupuncture. In particular the efficacy of laser acupuncture is disputed [2,22,24,26]. The purpose of this study was to evaluate the analgesic efficacy of acupuncture on painful heat stimuli under controlled experimental conditions and to compare the effects of laser acupuncture and needle acupuncture.
Correspondence lo: Prof. Dr. C.E. Elger, UniversitatsNervenklinik, Epileptologie, Sigmund Freud-Strasse 25, D-5300 Bonn 1, F.R.G.
03043959/90/$03.50
Pain threshold
0 1990 Elsevier Science Publishers
Probationers Healthy, unpaid volunteers, who were informed about the purpose and course of the experiment, served as probationers (informed consent). In the laser acupuncture study, 39 probationers took part (age range: 18-54 years, 26 female and 13 male), whereas 40 subjects participated in the study of needle acupuncture (age range: 22-54 years, 23 female and 17 male). Painful stimulation Cutaneous heat stimuli were administered as experimental painful stimuli. As a device for heating, the head of a needle-thermo-printer was used, which was controlled by a personal computer. It allowed a very quick increase and decrease of temperature. The temperature of 43°C was kept
B.V. (Biomedical
Division)
constant, while the length of the stimulus was varied. In order to avoid burns, a safety measure prevented heating for longer than 10 sec. The painful stimulus was administered to the ventral side of the left forearm. Pain threshold was defined as the length (in msec) of the heat stimulus necessary for the patient to perceive the painful sensation. In order to determine the pain threshold, the computer gave 20 randomized stimuli of different lengths. The probationers had to state when they perceived a stimulus. The mean value of minimal length still perceived was taken as pain threshold. The pain threshold was measured before and 10 min after acupuncture. Acupuncture and point choice The point Hegu (L.I.4) between the first and second bone of the metacarpus, which is reported as the point with the best analgesic efficacy, was used [7,23]. As a second point following the classi-
cal Chinese instructions the extraordinary point Jianqian (Extra.) under the lateral end of the clavicle was chosen [7]. A pulsed helium-neon laser with a maximal output of 10 mW was used for laser acupuncture. The emitted linear polarised red light had a wavelength of 632 nm. To maintain double-blind conditions the laser rayon was shielded by a little tube, which was placed directly on the acupuncture point. In a randomized. double-blind procedure, each probationer received 1 day of testing real laser acupuncture. and 1 day placebo laser acupuncture. Placebo means that the laser was put into position but not activated. The 4 acupuncture points (Hegu and Jianqian on both sides) were irradiated for 1 min each. Stainless steel needles were used for needle acupuncture (5 cm long, 30 gauge thick). The point Hegu (L.1.4) on both sides was needled 1 cm deep. The needles were slowly rotated about 180” and then rested for 10 min. Following a randomized procedure the
Fig. 1. Changes of pain threshold (in W) after laser acupuncture and placebo laser acupuncture under double-blind conditions for each probationer (n = 39).
183
ture and placebo laser acupuncture, respectively. The change of the pain threshold in percent is shown for each probationer in Fig. 1. From there a large inter-individual variability can be derived. The average increase of pain threshold after laser acupuncture was +41.1%, after placebo laser acupuncture only + 9.36%. The comparison of the median values ( + 9% after laser acupuncture, + 6% after placebo) showed very little difference. Changes of pain threshold compared with the initial value and differences between laser and placebo acupuncture were not statistically significant.
40 probationers were divided into a group which received real acupuncture, and a control group. For the placebo needle acupuncture a point locaked 1 cm proximal and 2 mm lateral of the point Hegu was needled in the same way as described for real acupuncture. Data analysis Data obtained in the laser acupuncture test were analysed using the Wilcoxon matched pair signed rank statistic. Data obtained in the needle acupuncture test were analysed with the Wilcoxon, Mann-Whitney rank statistic.
Effects of needle acupuncture Forty probationers participated in the study of needle acupuncture; real needle acupuncture was administered to 25, the placebo needle acupuncture to 15. Percentual changes of pain threshold are shown in Fig. 2. The average increase of pain
Results Effects of laser acupuncture Pain threshold was measured in 39 probationers before and 10 min after laser acupunc-
Changes of Pain Threshold
in %
400%
300%
200%
-I
Needle
!8@ Placebo 100%
0%
1
6
11
16
21
26
31
36
Probationers Fig. 2. Changes of pain threshold (in %) after needle acupuncture
and placebo needle acupuncture
each probationer
(n = 40).
under single-blind
conditions
for
1x4
threshold after needle acupuncture was + 50%, the median value + 33%. The change of pain threshold after needle acupuncture compared with the initial value was statistically significant (a = 0.1%). After placebo needle acupuncture the average change of pain threshold was + 7%, the median value - 11%. Compared with the initial value, the changes of pain threshold after placebo acupuncture are not statistically significant. Comparing the effects of needle acupuncture and placebo needle acupuncture, the difference is statistically significant (rr = 5%). The results of laser acupuncture and needle acupuncture were not compared. because the first study was performed under double-blind conditions. the second under single-blind conditions.
Discussion
As one of the first experimental studies concerning the effect of laser acupuncture and needle acupuncture on pain threshold in man, this study showed no change in pain threshold after laser acupuncture whereas needle acupuncture caused a significant change in pain threshold. Laser acupuncture is often used for various indications without a critical attitude [2.8,21,23,26]. But few controlled experimental or clinical studies exist concerning the efficacy of laser acupuncture. A single-blind study with patients suffering from chronic pain showed the superiority of laser acupuncture compared with a placebo treatment [14]. Contrary to that result, in a study of 513 patients in an accident surgery clinic, needle acupuncture was followed by pain relief, diminution of edema and amelioration of mobility, whereas laser acupuncture showed no significant change of pain or other troubles [22]. In an animal experiment a marked increase in pain threshold was produced by electro-acupuncture and morphine inje!tions. whereas laser acupuncture with a He-Ne or GaAs low power laser showed no analgesic efficacy [15]. In accordance with the results of Rabl et al. [22] and Lundberg et al. [15] the present double-blind study in 39 probationers did not show any statistically significant change of pain threshold after laser acupuncture compared to the initial value and no differences compared with the placebo
treatment. An explanation for the inefficacy 01 laser acupuncture may be the fact that laser acu-. puncture does not evoke the characteristic needling feeling ‘Te Chi’. which is described as a sensation of heaviness, tension and numbness. This needling feeling is considered as to be necessary for the efficacy of acupuncture ]4,7,12.18.24]. Concerning needle acupuncture, many clinical and experimental studies in animals show the analgesic effectiveness of needle acupuncture [7.12.13.1X--20,24]. Despite this, only a few controlled, experimental studies have been carried out in man. Chapman showed that needle acupuncture of the point Hegu (L.l.4) as well as inhalation of 33% nitrous oxide caused a significant increase of pain threshold in voluntary probationers, but needling of a placebo point had no effect on pain threshold [5]. In accordance with the results of Chapman et al., the present study showed the hypalgesic efficacy of needling the acupuncture point Hegu (L.I.4). The increase of pain threshold compared with the initial value and the difference to the placebo group were statistically significant. Concerning the mechanisms of needle acupuncture, different models are discussed. Nerval afferences seem to be important for the acupuncture analgesia [I 1.12,17,19]. The implications of the ‘gate control theory’ of Melzack and Wall for acupuncture analgesia have been discussed [10.12,18,20,24,25]. Recent results contradict the hypothesis of a gate control mechanism and a pure segmental pain inhibition as mechanisms of acupuncture analgesia [10.25]. The present results suggest that the hypothesis of a segmental inhibition of nociceptive afferences is not sufficient to explain acupuncture analgesia. as the acupuncture point Hegu and the point for cutaneous heat stimulation are localised in different dermatomes. The question whether it is important to needle the acupuncture point exactly or whether the needling itself irrespective of the localisation has an analgesic effect is still a matter of dispute [1.557,12,16,18,24]. The present study showed a statistically significant difference between needling of the point Hegu (L.1.4) and the placebo point 1 cm apart. It is generally difficult to deduce the clinical effectiveness of an analgesic treatment from ex-
185
perimental results [3,9]. Despite this the results of the present study can be taken as a basis for an augmented use of needle acupuncture in pain therapy and anesthesiology.
13 Kaada, B., Neurophysiology and acupuncture: a review, Adv. Pain Res. Ther., 1 (1976) 733-742. 14 Kreczi, Th. and Klinger, D., A comparison of laser acupuncture versus placebo in radicular and pseudoradicular pain syndromes as recorded by subjective response of patients, Acupunct. Electra-ther. Res. Int. J., 11 (1986) 207216.
References
15 Lundberg, T., Hode, L. and Zhou, J., A comparative study of pain-relieving effect of laser treatment and acupuncture, Acta Physiol. Stand., 131 (1987) 161-162. 16 Lynn, B. and Perl, E.R., Failure of acupuncture to produce localised analgesia, Pain, 3 (1977) 339-351. 17 Mayer, D.J., Price, D.D., Barber, J. and Rafii, A., Acupuncture analgesia: evidence for activation of a pain inhibitory system as mechanism of action, Ado. Pain Res. Ther., 1 (1976) 751-754. 18 Nguyen, V.N., Akupunktur-Analgesic, Med. Lit. Verlagsgesellschaft, Uelzen, 1978. 19 Pauser, G., Experimentelle Ergebnisse zur Objektivierbarkeit der Akupunkturhypalgesie. In: R. Frey and H.U. Gerbershagen (Eds.), Schmerz und Schmerzbehandlung Heute, Thieme, Stuttgart, 1977. 20 Pongratz, W., Akupunktur in der Aniisthesiologie, Thieme, Stuttgart, 1982. anesthesia and therapy in the 21 Qin, J.-N., Laser acupuncture People’s Republic of China, Ann. Acud. Med., 16 (1987) 261-263. 22 Rabl, V., Hertz, H., Bochdansky, Th., Kern, H. and Meng, A., Anwendung verschiedener Formen der Akupunktur und Therapie mit Lokalanlsthetika im Rahmen der unfallchirurgischen Nachbehandlung, Unfallheilkunde, 86 (1983)370-377. 23 Shibuya, M., Ono, R., Fugisawa, K., Katada, K., Sanao, H., Sano, T. and Oshiro, T., Laser-acupuncture therapy for pain and vague complaints in neurosurgery, No shinkei geka/Neurol. Surg., 13 (1985) 607-612. 24 Stux, G., Stiller, N., Pothmann, R. and Jayasuriya, A., Akupunktur - Lehrbuch und Atlas, Springer, Heidelberg, 1985. 25 Yan, Z. and Zonglian, H., The peripheral pathway of afferent impulses in traditional acupuncture analgesia, Schmerz/Pain/Douleur, 10 (1989) 15-18. 26 Yo-Cheng, Z., An advanced clinical trial with laser acupuncture for minor operations in the oromaxillofacial region, Losers Surg. Med., 4 (1984) 297-303.
1 Anderson, A.S. and Holmgren, E., Pain threshold effects of peripheral conditioning stimulation, Ado. Pain Res. Ther., 1 (1976) 761-768. 2 Bahn, J., Laser- und Infrarotstrahlen in der Akupunktur, Haug, Heidelberg, 1982. 3 Bromm, B. and Scharein, E., Quantifizierbare Reaktionsparameter bei wiederholten Schmerzreizen im Humanexperiment. In: A. Struppler and M. Gessler (Eds.), Schmerzforschung, Schmerzmessung, Brustschmerz, Springer, Berlin, 1981, pp. 77-84. 4 Chang, H.-T., Acupuncture analgesia today, Chin. Med. J., 92 (1979) 7-16. 5 Chapman, R.C., Wilson, E.M. and Gehring, J.D., Signal detection evaluation of effects of acupuncture on the perception of painful dental stimulation, Adu. Pain Res. Ther., 1 (1976) 775-779. 6 Devoghel, J.L. and Lamy, M., Anesthesie et analgesic acupuncturales, Rev. M&i, (Liege), 18 (1985) 624-627. I Essentials of Chinese Acupuncture, Foreign Language Press, Beijing, 1980. of chronic pain, 8 Floter, Th., Laser in the management Acupunct. Electra-ther. Res. Int. J., 11 (1986) 300. 9 Handwerker, H.O., Psychometric experimentell induzierter Schmerzempfindungen. In: A. Struppler and M. Gessler (Eds.), Schmerzforschung Schmerzmessung, Brustschmerz, Springer, Berlin, 1981, pp. 115-121. H.O., Physiologische Hypothesen iiber die 10 Handwerker, Akupunkturhypalgesie, Schmerz/Pain/Douleur, 10 (1989) l-6. 11 Hyodo, M. and Masayama, K., Acupuncture anesthesia and the pain threshold, Adu. Pain Res. Ther., 1 (1976) 787-795. 12 Kaada, B., Hoel, E., Leseth, K., Nygaard-Ostby, B., SetekIeiv, I. and Stovner, J., Acupuncture analgesia in the People’s Republic of China, T. Norske Loegeforen., 94 (1974) 417-442.
Pain, 43 (1990) 181-185 Elsevier
PAIN 01674
Hypalgesic efficacy of acupuncture on experimental pain in man. Comparison of laser acupuncture and needle acupuncture A. Brockhaus Universiiiits-Nervenklinik, (Received
1 December
and C.E. Elger Epileptologie,
1989, revision received 9 February
Bonn (F.R.G.) 1990, accepted
31 May 1990)
The analgesic effect of acupuncture on cutaneous heat stimuli of 43’C has been evaluated in a controlled Summary experimental study with healthy, informed volunteers. Laser acupuncture was administered to 39 probationers using a hetium-neon laser under double-blind conditions. The point Hegu (L.I.4) and Jianqian (Extra.) on both sides were each irradiated for 1 mm. Forty probationers were needled with stainless steel needles in the point Hegu (L.I.4) on both sides under single-blind conditions. Pam threshold was measured in terms of the time (in msec) that the probationers needed to perceive the cutaneous heat stimulus of 43°C. The painful stimulus was generated by a computer-controlled standardized procedure. The Wilcoxon test was used for the statistical evaluation. Laser acupuncture did not change the pain threshold. Needle acupuncture did, however, increase the pain threshold compared with the initial value (a = 0.1%). The difference compared with the control group, where a placebo point was needled, was also significant (a = SW). This controlled experimental study proves the analgesic effect of needle acupuncture on painful heat stimuli. Laser acupuncture had no effect on pain threshold in this study. Key wordsz Needle
acupuncture;
Laser acupuncture;
Analgesia;
Introduction
Methods
Acupuncture is used worldwide for the treatment of acute and chronic pain [12,20], and yet there are only a few experimental studies under controlled conditions, which prove the analgesic efficacy of acupuncture. In particular the efficacy of laser acupuncture is disputed [2,22,24,26]. The purpose of this study was to evaluate the analgesic efficacy of acupuncture on painful heat stimuli under controlled experimental conditions and to compare the effects of laser acupuncture and needle acupuncture.
Correspondence lo: Prof. Dr. C.E. Elger, UniversitatsNervenklinik, Epileptologie, Sigmund Freud-Strasse 25, D-5300 Bonn 1, F.R.G.
03043959/90/$03.50
Pain threshold
0 1990 Elsevier Science Publishers
Probationers Healthy, unpaid volunteers, who were informed about the purpose and course of the experiment, served as probationers (informed consent). In the laser acupuncture study, 39 probationers took part (age range: 18-54 years, 26 female and 13 male), whereas 40 subjects participated in the study of needle acupuncture (age range: 22-54 years, 23 female and 17 male). Painful stimulation Cutaneous heat stimuli were administered as experimental painful stimuli. As a device for heating, the head of a needle-thermo-printer was used, which was controlled by a personal computer. It allowed a very quick increase and decrease of temperature. The temperature of 43°C was kept
B.V. (Biomedical
Division)
constant, while the length of the stimulus was varied. In order to avoid burns, a safety measure prevented heating for longer than 10 sec. The painful stimulus was administered to the ventral side of the left forearm. Pain threshold was defined as the length (in msec) of the heat stimulus necessary for the patient to perceive the painful sensation. In order to determine the pain threshold, the computer gave 20 randomized stimuli of different lengths. The probationers had to state when they perceived a stimulus. The mean value of minimal length still perceived was taken as pain threshold. The pain threshold was measured before and 10 min after acupuncture. Acupuncture and point choice The point Hegu (L.I.4) between the first and second bone of the metacarpus, which is reported as the point with the best analgesic efficacy, was used [7,23]. As a second point following the classi-
cal Chinese instructions the extraordinary point Jianqian (Extra.) under the lateral end of the clavicle was chosen [7]. A pulsed helium-neon laser with a maximal output of 10 mW was used for laser acupuncture. The emitted linear polarised red light had a wavelength of 632 nm. To maintain double-blind conditions the laser rayon was shielded by a little tube, which was placed directly on the acupuncture point. In a randomized. double-blind procedure, each probationer received 1 day of testing real laser acupuncture. and 1 day placebo laser acupuncture. Placebo means that the laser was put into position but not activated. The 4 acupuncture points (Hegu and Jianqian on both sides) were irradiated for 1 min each. Stainless steel needles were used for needle acupuncture (5 cm long, 30 gauge thick). The point Hegu (L.1.4) on both sides was needled 1 cm deep. The needles were slowly rotated about 180” and then rested for 10 min. Following a randomized procedure the
Fig. 1. Changes of pain threshold (in W) after laser acupuncture and placebo laser acupuncture under double-blind conditions for each probationer (n = 39).
183
ture and placebo laser acupuncture, respectively. The change of the pain threshold in percent is shown for each probationer in Fig. 1. From there a large inter-individual variability can be derived. The average increase of pain threshold after laser acupuncture was +41.1%, after placebo laser acupuncture only + 9.36%. The comparison of the median values ( + 9% after laser acupuncture, + 6% after placebo) showed very little difference. Changes of pain threshold compared with the initial value and differences between laser and placebo acupuncture were not statistically significant.
40 probationers were divided into a group which received real acupuncture, and a control group. For the placebo needle acupuncture a point locaked 1 cm proximal and 2 mm lateral of the point Hegu was needled in the same way as described for real acupuncture. Data analysis Data obtained in the laser acupuncture test were analysed using the Wilcoxon matched pair signed rank statistic. Data obtained in the needle acupuncture test were analysed with the Wilcoxon, Mann-Whitney rank statistic.
Effects of needle acupuncture Forty probationers participated in the study of needle acupuncture; real needle acupuncture was administered to 25, the placebo needle acupuncture to 15. Percentual changes of pain threshold are shown in Fig. 2. The average increase of pain
Results Effects of laser acupuncture Pain threshold was measured in 39 probationers before and 10 min after laser acupunc-
Changes of Pain Threshold
in %
400%
300%
200%
-I
Needle
!8@ Placebo 100%
0%
1
6
11
16
21
26
31
36
Probationers Fig. 2. Changes of pain threshold (in %) after needle acupuncture
and placebo needle acupuncture
each probationer
(n = 40).
under single-blind
conditions
for
1x4
threshold after needle acupuncture was + 50%, the median value + 33%. The change of pain threshold after needle acupuncture compared with the initial value was statistically significant (a = 0.1%). After placebo needle acupuncture the average change of pain threshold was + 7%, the median value - 11%. Compared with the initial value, the changes of pain threshold after placebo acupuncture are not statistically significant. Comparing the effects of needle acupuncture and placebo needle acupuncture, the difference is statistically significant (rr = 5%). The results of laser acupuncture and needle acupuncture were not compared. because the first study was performed under double-blind conditions. the second under single-blind conditions.
Discussion
As one of the first experimental studies concerning the effect of laser acupuncture and needle acupuncture on pain threshold in man, this study showed no change in pain threshold after laser acupuncture whereas needle acupuncture caused a significant change in pain threshold. Laser acupuncture is often used for various indications without a critical attitude [2.8,21,23,26]. But few controlled experimental or clinical studies exist concerning the efficacy of laser acupuncture. A single-blind study with patients suffering from chronic pain showed the superiority of laser acupuncture compared with a placebo treatment [14]. Contrary to that result, in a study of 513 patients in an accident surgery clinic, needle acupuncture was followed by pain relief, diminution of edema and amelioration of mobility, whereas laser acupuncture showed no significant change of pain or other troubles [22]. In an animal experiment a marked increase in pain threshold was produced by electro-acupuncture and morphine inje!tions. whereas laser acupuncture with a He-Ne or GaAs low power laser showed no analgesic efficacy [15]. In accordance with the results of Rabl et al. [22] and Lundberg et al. [15] the present double-blind study in 39 probationers did not show any statistically significant change of pain threshold after laser acupuncture compared to the initial value and no differences compared with the placebo
treatment. An explanation for the inefficacy 01 laser acupuncture may be the fact that laser acu-. puncture does not evoke the characteristic needling feeling ‘Te Chi’. which is described as a sensation of heaviness, tension and numbness. This needling feeling is considered as to be necessary for the efficacy of acupuncture ]4,7,12.18.24]. Concerning needle acupuncture, many clinical and experimental studies in animals show the analgesic effectiveness of needle acupuncture [7.12.13.1X--20,24]. Despite this, only a few controlled, experimental studies have been carried out in man. Chapman showed that needle acupuncture of the point Hegu (L.l.4) as well as inhalation of 33% nitrous oxide caused a significant increase of pain threshold in voluntary probationers, but needling of a placebo point had no effect on pain threshold [5]. In accordance with the results of Chapman et al., the present study showed the hypalgesic efficacy of needling the acupuncture point Hegu (L.I.4). The increase of pain threshold compared with the initial value and the difference to the placebo group were statistically significant. Concerning the mechanisms of needle acupuncture, different models are discussed. Nerval afferences seem to be important for the acupuncture analgesia [I 1.12,17,19]. The implications of the ‘gate control theory’ of Melzack and Wall for acupuncture analgesia have been discussed [10.12,18,20,24,25]. Recent results contradict the hypothesis of a gate control mechanism and a pure segmental pain inhibition as mechanisms of acupuncture analgesia [10.25]. The present results suggest that the hypothesis of a segmental inhibition of nociceptive afferences is not sufficient to explain acupuncture analgesia. as the acupuncture point Hegu and the point for cutaneous heat stimulation are localised in different dermatomes. The question whether it is important to needle the acupuncture point exactly or whether the needling itself irrespective of the localisation has an analgesic effect is still a matter of dispute [1.557,12,16,18,24]. The present study showed a statistically significant difference between needling of the point Hegu (L.1.4) and the placebo point 1 cm apart. It is generally difficult to deduce the clinical effectiveness of an analgesic treatment from ex-
185
perimental results [3,9]. Despite this the results of the present study can be taken as a basis for an augmented use of needle acupuncture in pain therapy and anesthesiology.
13 Kaada, B., Neurophysiology and acupuncture: a review, Adv. Pain Res. Ther., 1 (1976) 733-742. 14 Kreczi, Th. and Klinger, D., A comparison of laser acupuncture versus placebo in radicular and pseudoradicular pain syndromes as recorded by subjective response of patients, Acupunct. Electra-ther. Res. Int. J., 11 (1986) 207216.
References
15 Lundberg, T., Hode, L. and Zhou, J., A comparative study of pain-relieving effect of laser treatment and acupuncture, Acta Physiol. Stand., 131 (1987) 161-162. 16 Lynn, B. and Perl, E.R., Failure of acupuncture to produce localised analgesia, Pain, 3 (1977) 339-351. 17 Mayer, D.J., Price, D.D., Barber, J. and Rafii, A., Acupuncture analgesia: evidence for activation of a pain inhibitory system as mechanism of action, Ado. Pain Res. Ther., 1 (1976) 751-754. 18 Nguyen, V.N., Akupunktur-Analgesic, Med. Lit. Verlagsgesellschaft, Uelzen, 1978. 19 Pauser, G., Experimentelle Ergebnisse zur Objektivierbarkeit der Akupunkturhypalgesie. In: R. Frey and H.U. Gerbershagen (Eds.), Schmerz und Schmerzbehandlung Heute, Thieme, Stuttgart, 1977. 20 Pongratz, W., Akupunktur in der Aniisthesiologie, Thieme, Stuttgart, 1982. anesthesia and therapy in the 21 Qin, J.-N., Laser acupuncture People’s Republic of China, Ann. Acud. Med., 16 (1987) 261-263. 22 Rabl, V., Hertz, H., Bochdansky, Th., Kern, H. and Meng, A., Anwendung verschiedener Formen der Akupunktur und Therapie mit Lokalanlsthetika im Rahmen der unfallchirurgischen Nachbehandlung, Unfallheilkunde, 86 (1983)370-377. 23 Shibuya, M., Ono, R., Fugisawa, K., Katada, K., Sanao, H., Sano, T. and Oshiro, T., Laser-acupuncture therapy for pain and vague complaints in neurosurgery, No shinkei geka/Neurol. Surg., 13 (1985) 607-612. 24 Stux, G., Stiller, N., Pothmann, R. and Jayasuriya, A., Akupunktur - Lehrbuch und Atlas, Springer, Heidelberg, 1985. 25 Yan, Z. and Zonglian, H., The peripheral pathway of afferent impulses in traditional acupuncture analgesia, Schmerz/Pain/Douleur, 10 (1989) 15-18. 26 Yo-Cheng, Z., An advanced clinical trial with laser acupuncture for minor operations in the oromaxillofacial region, Losers Surg. Med., 4 (1984) 297-303.
1 Anderson, A.S. and Holmgren, E., Pain threshold effects of peripheral conditioning stimulation, Ado. Pain Res. Ther., 1 (1976) 761-768. 2 Bahn, J., Laser- und Infrarotstrahlen in der Akupunktur, Haug, Heidelberg, 1982. 3 Bromm, B. and Scharein, E., Quantifizierbare Reaktionsparameter bei wiederholten Schmerzreizen im Humanexperiment. In: A. Struppler and M. Gessler (Eds.), Schmerzforschung, Schmerzmessung, Brustschmerz, Springer, Berlin, 1981, pp. 77-84. 4 Chang, H.-T., Acupuncture analgesia today, Chin. Med. J., 92 (1979) 7-16. 5 Chapman, R.C., Wilson, E.M. and Gehring, J.D., Signal detection evaluation of effects of acupuncture on the perception of painful dental stimulation, Adu. Pain Res. Ther., 1 (1976) 775-779. 6 Devoghel, J.L. and Lamy, M., Anesthesie et analgesic acupuncturales, Rev. M&i, (Liege), 18 (1985) 624-627. I Essentials of Chinese Acupuncture, Foreign Language Press, Beijing, 1980. of chronic pain, 8 Floter, Th., Laser in the management Acupunct. Electra-ther. Res. Int. J., 11 (1986) 300. 9 Handwerker, H.O., Psychometric experimentell induzierter Schmerzempfindungen. In: A. Struppler and M. Gessler (Eds.), Schmerzforschung Schmerzmessung, Brustschmerz, Springer, Berlin, 1981, pp. 115-121. H.O., Physiologische Hypothesen iiber die 10 Handwerker, Akupunkturhypalgesie, Schmerz/Pain/Douleur, 10 (1989) l-6. 11 Hyodo, M. and Masayama, K., Acupuncture anesthesia and the pain threshold, Adu. Pain Res. Ther., 1 (1976) 787-795. 12 Kaada, B., Hoel, E., Leseth, K., Nygaard-Ostby, B., SetekIeiv, I. and Stovner, J., Acupuncture analgesia in the People’s Republic of China, T. Norske Loegeforen., 94 (1974) 417-442.
