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During acupuncture treatment, tonification (reinforcing) and sedation (reduction) techniques are used to maximise treatment effectiveness.1 Needle manipulation is highly individualised among acupuncturists, and there is no established standard. Quantification of needle movements during insertion and manipulation has also been a challenge.2 However, recent three-dimensional (3D) motion tracking technology using an infrared system (Acusensors)3 4 and an electromagnet (trakSTAR)5 has enabled the quantification of needle movement. Through the measurement of displacement, rotation, torque and force, studies have found significant variations in amplitude and duration of needling between practitioners when instructed to perform acupuncture in their own fashion, but the movement was consistent between acupuncturists.3 4 In addition to the displacement, the aim of our study was to analyse the magnitude and speed of needle movement during the lifting and thrusting movements of tonification and sedation.
The participants were recruited from both public and private Traditional Chinese Medicine (TCM) clinics in Singapore. Ethics approval was sought from the Singhealth’s Centralised Review Institutional Review Board (CIRB Ref: 2016/2765).
The acupuncture needle insertion was conducted on floral foam (figure 1A). A 0.30×50 mm disposable stainless steel acupuncture needle was used. The acupuncturists were instructed to perform the following needle insertion techniques: (1) heavy thrusting and light lifting; and (2) light lifting and heavy thrusting. Each technique was repeated 10 times, and the five consistent patterns were used for data analysis.
Needle motion tracking was conducted using a 3D electromagnetic motion tracking system. Data on needle insertion (y-axis) were obtained. We demonstrated the ability of a 3D tracking device to record and quantify the needle and finger movement of acupuncturists in our previous study.5 In this study, four sensors were utilised. The sensors were secured using micropore tape to the tip of the needle handle (figure 1B), thumb, index and middle fingers (figure 1C).
The graphs for the y-axis (measuring the distance of needle movement over time) was plotted to observe the needle movement trend. SPSS was used for statistical analysis. Descriptive statistics were used to describe the participants’ profile, and the magnitude and speed of thrusting and lifting. Repeated measures analysis of variance (ANOVA) was used to assess for consistency in needle movement within subjects. Pearson’s correlation and independent t-tests were used to test for associations between needle movement and participant profile. A value of p<0.05 was used to determine whether the result was significant.
Fifteen acupuncturists participated in the study. The mean age was 38.9±17.6 years (range 25–74). The majority were females (n=12, 80%). The acupuncturists had 11.7±14.1 years (range 1–44) of experience. For the heavy thrusting and light lifting technique, data from 12 participants were included. For the light lifting and heavy thrusting technique, data from 13 participants were included. Participants who did not display any consistent patterns from the needle movement graphs were excluded.
Magnitude and speed of lifting and thrusting
In technique 1, the magnitude of the needle during heavy thrusting was 3.00±7.90 (range 0.05–28.53) and speed was 156.61±536.28 (range 0.09–1859.49). The magnitude of the needle during light lifting was 3.05±8.06 (range 0.05–28.53) and speed was 160.14±548.56 (range 0.07–1902.03). In technique 2, the magnitude of the needle during light lifting was 0.48±0.90 (range 0.02–2.62) and speed was 2.53±6.67 (range 0.02–24.51). The magnitude of the needle during heavy thrusting was 0.83±1.55 (range 0.02–5.21) and speed was 19.71±62.69 (range 0.07–227.97). Graphical plots of the needle movements for both techniques also showed variations in needle movement patterns. Two examples of the graphical plots of the needle for techniques 1 and 2 are shown in figure 1D, E, respectively (table 1).
For both techniques, the magnitude and speed of the needle was greater than the fingers, but displayed a large range. This suggests high variability among acupuncturists. The magnitude and speed of technique 1 for both thrusting and lifting were greater than for technique 2.
Consistency of magnitude and speed within subjects
The differences in magnitude and speed for all parameters (needle, thumb, index finger, and middle finger) among acupuncturists were not significant. The magnitude and speed of needle insertion and finger movement were consistent among acupuncturists for both techniques (all p>0.05).
Association between demographic and needle movement
For both techniques, age was found to be positively associated with the speed of heavy thrusting of the needle (technique 1: r=0.67, p=0.02; technique 2: r=0.58, p=0.04) and middle finger (technique 1: r=0.75, p=0.005; technique 2: r=0.69, p=0.009). Years of experience was also associated with the speed of the middle finger (technique 1: r=0.60, p=0.04; technique 2: r=0.63, p=0.02), with more experienced acupuncturists inserting the needle at greater speed. There was no association of the techniques with gender.
Our study found that there was high variability in magnitude and speed among acupuncturists as indicated by the large range in these values. Although there was high variability among acupuncturists, the movements were mostly consistent as there were no significant differences found for within-subject comparisons. This finding is similar to results of previous studies.3 4 We concluded that the practice of acupuncture is highly individualised. Without a standard range for magnitude and speed, it is challenging to develop assessment criteria for acupuncture students, and the assessment could be largely subjective.
From an analysis of the association between demographics and needle movement, we found that age and years of experience were associated with magnitude and speed. Participants who were older and more experienced tended to produce larger magnitude and speed during needle insertion. This suggested that more experienced acupuncturists could be more aggressive in their delivery of acupuncture. Further studies could be conducted to analyse this phenomenon, and to clarify the effects of needle magnitude and speed on acupuncture treatment.
The authors would like to thank the participants in this study.
Contributors ML, TC and SCT conceptualised the study. TC performed the experiments. ML performed the data analysis. All authors were involved in manuscript writing and approved the final version accepted for publication.
Funding This study was funded by the Biomechanics Laboratory Programme Grant and the Surgery Academic Clinical Program seed grant (reference no. GRSG13NSL). Both grants are funded by the SingHealth Duke-NUS Academic Medical Centre, facilitated by the Joint Office of Academic Medicine (JOAM). It is an initiative of Surgery Academic Clinical Programme (SURG ACP), hosted at the Singapore General Hospital (SGH).
Competing interests None declared.
Patient consent Obtained.
Ethics approval Singhealth IRB.
Provenance and peer review Not commissioned; internally peer reviewed.
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