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Quantification of needle movements during insertion and manipulation has been a challenge for acupuncturists.1 Needle manipulation includes lifting and thrusting of the needle and/or needle rotation after insertion. Such movements are critical for the elicitation of de qi and maximisation of treatment effectiveness. However, needle manipulation is highly individualised among acupuncturists, and this could have implications for treatment outcomes. Two studies have explored the displacement, rotation, torque and force exerted during needle manipulation using motion sensors (Acusensors).2 ,3 However, they did not include the speed of needle insertion and rotation. Our study aimed to analyse the trajectory of acupuncture needle motion from insertion to rotation manipulation to achieve de qi.
Acupuncture needle insertion
We performed acupuncture needle insertion on a study team member. The team member signed an institutional informed consent form acknowledging that he knew the procedure involved during acupuncture, and understood the possible risks and complications. The acupuncture was performed by a certified acupuncturist with more than 20 years of experience. A 0.30×50 mm disposable stainless steel acupuncture needle was used. The acupuncture point used in this study was LI11 (Quchi), located at the lateral end of the transverse cubital crease connecting LU5 with the lateral epicondyle of the humerus.4 Needle manipulation was conducted until the acupuncturist felt a change in tissue behaviour and the subject verbalised achievement of de qi.
Needle motion tracking was conducted using a three-dimensional electromagnetic motion tracking system (trakSTAR, Ascension Technology, Corporation, Burlington,Vermont, USA). A direct current electromagnetic transmitter (mid-range model) and a six-degree-of-freedom sensor with a diameter of 0.9 mm (Model 90) was used (figure 1A). The sensor was taped to the tip of the needle handle (figure 1B). The device was set at 80 counts per second.
Data collection and analysis
We collected data on needle insertion (y-axis) and rotation around the x-axis (azimuth) during manipulation. Data from the motion tracking system were exported into Microsoft Excel 2013. The graphs for the y-axis (measuring the distance of needle movement over time) and azimuth (rotation of the needle) were plotted.
Speed of needle insertion and rotation
The speed of needle insertion was calculated using the following formula:|Y1−Y2|/(1/80) (figure 2A). Hence, |−15.205+11.843|×80=3.362×80=268.96 mm/s≈27 cm/s. During needle insertion, the needle was rotated anticlockwise followed by clockwise, reflected by two sharp peaks corresponding with the needle insertion. The needle was rotated a maximum of 180° clockwise and anticlockwise. The speed of needle insertion was calculated in radians using the following formula: (change in azimuth×π/180°)/(1/80). Hence, 360×π/180°×80=6.283×80=502.6 rad/s. After needle insertion, smaller anticlockwise rotations were made to elicit de qi. These smaller rotations were performed at a lower speed. The trajectory of the needle rotation is illustrated in figure 2B, and figure 2C combines the data from figure 2A and B.
Our study has validated the use of a motion tracking system to evaluate the speed of acupuncture needle insertion and rotation patterns during acupuncture needle manipulation. The needle was inserted at 27 cm/s, and the needle was rotated 180° clockwise and anticlockwise during insertion at a maximum of 502.6 rad/s. The graphical plots from our study results corroborated our visual observation of needle movement during insertion and rotation. We could repeat this study with a larger sample of experienced acupuncturists to help develop a general standard method of needle insertion technique. These data could then be used in clinical education to teach and provide an objective measure to evaluate the needling skills of acupuncture students.
During needle manipulation, lifting and thrusting motions can be broadly divided into heavy thrusting accompanied by light lifting (reinforcing manipulation), and light thrusting followed by light lifting (reducing manipulation). Gentle and slow clockwise rotation and rapid large anticlockwise rotation angles, respectively, can also be used to ‘reinforce’ and ‘reduce’, respectively, after achievement of de qi. We propose analysing these other needle motion methods in future studies. Using the motion device, the speed of the lifting and thrusting technique can be evaluated using the change in values from the y-axis, and the angle and speed of rotation can be studied using azimuth and the combination of azimuth and y-axis values, respectively.
The authors would like to thank Ms Ita Suzana Bin Mat Jais for guiding us on the use of the trakSTAR device.
Correction notice This article has been corrected since it was published Online First. Figure 1 caption should read:
(A) Motion tracking device (trakSTAR). (B) Needle attached to motion sensor, and needle placed at LI11 (Quchi).
Contributors MQHL, TC and SCT conceptualised the study. MQHL performed data analysis. SLC performed the acupuncture. All authors were involved in manuscript writing.
Competing interests None declared.
Participant consent obtained.
Provenance and peer review Not commissioned; internally peer reviewed.
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