A Mechanical Construction to Enhance the Stability and Safety of Lifting and Thrusting Manipulation of Acupuncture

This protocol designs a cannula that can be used to control the range of motion for the lifting and thrusting manipulation in acupuncture, thereby improving stability and safety. It can thus serve both the clinical application and scientific research of acupuncture treatment.

The therapeutic effectiveness of acupuncture relies on both safety and stability, making these factors essential in acupuncture manipulation research. However, manual manipulation introduces unavoidable inaccuracies, which can impact the reliability of research findings. To address this challenge, a unique lifting and thrusting manipulation control cannula was designed in this study, offering flexible adjustment of movement amplitude. The cannula was created using 3D printing technology, and its effectiveness in maintaining stability was verified by recording the acupuncture needle's movement range with optical sensor technology. The study's results show that the control cannula significantly enhances the stability of acupuncture manipulation, reducing human error. This innovation suggests that the cannula could serve as a valuable auxiliary tool for ensuring both the precision and safety of acupuncture-related experimental research. Its adoption could also contribute to the standardization of acupuncture practices, ensuring more consistent and accurate research outcomes, which is essential for future advancements in acupuncture research and clinical applications.

Needling manipulation is performed after the needle is inserted into the patient's skin to either induce a needle sensation known as "DeQi" (which refers to the sensation of meridian qi induction at the acupuncture point) or to adjust the direction and intensity of the needle sensation. As an essential part of acupuncture, different needling techniques produce varying effects¹. Needling manipulation is a critical factor that affects the effectiveness of acupuncture treatment^2,3. Research has shown that the signals activated by the lifting-thrusting technique are stronger than those induced by other needling methods⁴.

The therapeutic effect of acupuncture is closely related to the intensity of stimulation^5,6,7, which, in turn, depends on the type of needling manipulation used. As a result, the quantitative-effect relationship of acupuncture manipulation is a key area of experimental research^8,9,10. Standardization and reproducibility are crucial to ensuring the scientific validity of acupuncture research¹¹. Both the lifting-thrusting and twisting methods require specific frequency and amplitude of operation^12,13, and the selection of acupoints is also important for treating diseases¹⁴. However, manual acupuncture relies on human operators, making it difficult to maintain consistent frequency and amplitude during needle manipulation¹⁵. Additionally, precautions must be taken to avoid complications such as pneumothorax by carefully controlling the depth and direction of needle insertion in certain areas of the body^16,17.

Thus, one of the most urgent challenges in the scientific study of acupuncture manipulation is the development of controllers to improve the stability of needling techniques, which is vital for ensuring the safety and standardization of acupuncture practices¹⁸.

Lifting-thrusting is one of the most commonly used basic acupuncture techniques. It involves lifting the needle up and thrusting it down after inserting it into the acupoint at a specific depth. The upward movement is called lifting, while the downward movement is known as thrusting. This process is repeated to achieve the desired clinical effect, with the level of stimulation depending on the amplitude and frequency of the lifting and thrusting motions^19,20,21,22. Currently, the amplitude of the lifting and thrusting technique is mainly controlled by the practitioner, and its effectiveness is often evaluated based on the sensation of "De Qi" (the feeling of meridian qi induction at the acupuncture point)^23,24,25. However, there is no established standard to evaluate the stability and safety of this technique, and the depth of needle insertion is entirely dependent on the practitioner's skill.

To promote standardization in acupuncture, several new techniques have been developed to replace traditional manual acupuncture, including pulsed electro-acupuncture, ultrasonic acupuncture, microwave acupuncture, laser acupuncture, and extracorporeal shock wave acupuncture²⁶. While these methods help to some extent in standardizing the effects of acupuncture, they cannot fully replace traditional manual acupuncture in clinical practice. Therefore, standardizing the manipulation of manual acupuncture remains essential.

To address the aforementioned issues, this study designed an acupuncture needle cannula that improves the safety and stability of the lifting and thrusting technique. The control cannula used in the study was manufactured using 3D printing technology (see Table of Materials), and the overall structure consists of three components: the cannula, the needle sleeve, and the adjustable stopper, along with disposable acupuncture needles (Figure 1). The cannula, needle sleeve, and adjustable stopper were all produced through 3D printing technology (see Supplementary File 1, Supplementary File 2, and Supplementary File 3).

The cannula offers several advantages: first, the amplitude is controlled by the stopper, which significantly reduces the burden on practitioners; second, the separation of the needle and cannula prevents contamination during acupuncture; and third, the adjustable scale allows for precise control of the needle's depth and amplitude, enabling free adjustment as needed. The results of this study provide a safe auxiliary tool for experimental research on acupuncture manipulation, which is crucial for advancing the standardization of acupuncture techniques.

All procedures in the protocol were conducted on commercially available human simulation materials (see Table of Materials) rather than on humans, so no ethical issues were involved in this study. Informed consent was also obtained from all volunteers who participated in the study. The participants in this experiment were 20 students from the College of Acumox and Tuina at Shanghai University of Traditional Chinese Medicine. These students had completed coursework on the acupuncture lifting and thrusting technique as part of the "Science of Acupuncture and Moxibustion"²⁷curriculum. Additionally, they had nearly a year of practical experience in human needling through lessons and hands-on practice. The details of the equipment and software used are listed in the Table of Materials.

1. Fabrication of the control cannula

1. Prepare the cannula, the needle sleeve, and the adjustable stopper using 3D printing technology.
2. Use white resin as the material for 3D printing to ensure a minimum precision of 0.1 mm, which prevents issues with structures not fitting together due to errors. This material is also more cost-effective and allows easier adjustment of the structure.

2. Videography

1. Camera settings
   1. Place two tripods in front of the operator's desk at an appropriate height and connect the two motion cameras. Set the angle between the two motion cameras to 60°-120° (Figure 2A).
   2. Adjust the camera settings as follows: resolution 1280 × 720 pixels, format MP4, full manual mode (M), aperture F1.2, shutter speed 1/1000s, ISO 6400, auto white balance, and optical zoom 0 mm.
2. Calibration settings
   1. Place a 3D calibration stand measuring 15 cm × 15 cm × 15 cm on the table (Figure 2B). Ensure it is within the coverage of the two motion cameras.
3. Tracking marker placement
   1. Prepare a passive infrared reflective sphere with a diameter of 6.5 mm. Attach it to the fingernail cap of the participant's right thumb to measure the movement trajectory.
4. Experimental operation
   NOTE: The twenty participants were instructed to perform lifting and thrusting manipulations on the human simulation material, including the following techniques: even lifting and thrusting, heavy thrusting with light lifting, and light thrusting with heavy lifting. Each participant completed the three types of manipulations on the human simulation material, both with and without a cannula set to an amplitude of 15 mm. They then repeated the three manipulations using cannulas with amplitudes of 5 mm, 10 mm, and 15 mm. A 30 min interval was provided between each manipulation session to ensure consistency among the participants. Each manipulation was repeated 10 times.
   1. Perform lifting and thrusting manipulations without cannula
      1. Even lifting and thrusting: Insert the needle to a depth of 20 mm. Lift the needle up and down at a uniform rate with an amplitude of 15 mm at a frequency of 60 times per minute.
      2. Heavy thrusting with light lifting: Insert the needle to a depth of 20 mm. Quickly insert the needle to a certain depth, then slowly withdraw it to the superficial layer with an amplitude of 15 mm at a frequency of 60 times per minute.
      3. Light thrusting with heavy lifting: Insert the needle to a depth of 20 mm. Slowly insert the needle to a certain depth, then rapidly withdraw it to a shallow layer with an amplitude of 15 mm at a frequency of 60 times per minute.
   2. Perform lifting and thrusting manipulations with cannula
      NOTE: Fabricate three cannulas that are compatible with the needle size. Adjust their amplitudes to 5 mm, 10 mm, and 15 mm by sliding the adjustable stoppers to the appropriate length.
      1. Manipulate with the cannula with an amplitude of 5 mm
         1. Even lifting and thrusting: Fix a needle in a needle sleeve. Place the needle sleeve in a cannula with an amplitude of 5 mm. Insert the needle to a depth of 20 mm and lift the cannula up and down at a uniform rate at a frequency of 60 times per minute.
         2. Heavy thrusting with light lifting: Use the same cannula. Insert the needle to a depth of 20 mm. Quickly insert the needle to the limited depth, then slowly withdraw it to the superficial layer at a frequency of 60 times per minute.
         3. Light thrusting with heavy lifting: Use the same cannula. Insert the needle to a depth of 20 mm. Slowly insert the needle to the limited depth, then rapidly withdraw it to the superficial layer at a frequency of 60 times per minute.
      2. Manipulate with the cannula with an amplitude of 10 mm
         1. Even lifting and thrusting: Fix a needle in a needle sleeve. Place the needle sleeve in a cannula with an amplitude of 10 mm. Insert the needle to a depth of 20 mm and lift the cannula up and down at a uniform rate at a frequency of 60 times per minute.
         2. Heavy thrusting with light lifting: Use the same cannula. Insert the needle to a depth of 20 mm. Quickly insert the needle to the limited depth, then slowly withdraw it to the superficial layer at a frequency of 60 times per minute.
         3. Light thrusting with heavy lifting: Use the same cannula. Insert the needle to a depth of 20 mm. Slowly insert the needle to the limited depth, then rapidly withdraw it to the superficial layer at a frequency of 60 times per minute.
      3. Manipulate with the cannula with an amplitude of 15 mm
         1. Even lifting and thrusting: Fix a needle in a needle sleeve. Place the needle sleeve in a cannula with an amplitude of 15 mm. Insert the needle to a depth of 20 mm and lift the cannula up and down at a uniform rate at a frequency of 60 times per minute.
         2. Heavy thrusting with light lifting: Use the same cannula. Insert the needle to a depth of 20 mm. Quickly insert the needle to the limited depth, then slowly withdraw it to the superficial layer at a frequency of 60 times per minute.
         3. Light thrusting with heavy lifting: Use the same cannula. Insert the needle to a depth of 20 mm. Slowly insert the needle to the limited depth, then rapidly withdraw it to the superficial layer at a frequency of 60 times per minute.

3. Project configuration of the motion capture and analysis software and video analysis

1. Video export and renaming
   NOTE: Transfer all video files from the camera to the designated storage disk on the computer. Rename the 3D calibration video files from cameras 1 and 2 to "1.mp4" and "2.mp4," respectively.
   1. Video storage
      1. Save the operation videos to the computer-designated storage disk. Name them using the participants' full initials in the format "xxx-1" and "xxx-2."
2. Reality motion system project configuration (motion capture and analysis software)
   1. New project: Start the motion capture and analysis software and select New Project. Set the project name in the project tab, then click on Create and Save to store the project on the specified storage disk.
   2. Specification: Select Specification > Points > Thumb Tip, drag the tracking point from the predefined point box to the used point box, and click on the Close button to continue.
   3. Adding camera groups: Right-click on the Cameras > Add Camera Group to add a new camera group.
   4. Select tracking file: Click on the Select File button in the Tracking box.
   5. Importing operation video: Click on Open Existing File and select the operation video xxx-1 in the popup window. Click on Apply to complete the video import.
   6. Import calibration video: Click on Select File in the 3D Calibration box to import the corresponding calibration video "1.mp4."
   7. Importing other videos: Following the same steps as in step 3.2.5, import the operation video "xxx-2" and its corresponding calibration video "2.mp4."
3. Video analysis
   1. Opening a camera group: Open the camera group, then right-click on 1.mp4 > Properties.
   2. Perform 3D calibration: Click on the 3D Calibration button in the 3D Calibration box, enter a description, and add 20 points by clicking on the Add Points button 20 times.
   3. Setting point parameters: Set the name and corresponding X, Y, Z values for each point, then click on Apply according to the calibration parameters.
   4. Finish calibration: After configuring all the points, click on each endpoint of the calibration video to complete the 3D calibration.
   5. Calibrate other cameras: Follow steps 3.3.1-3.3.4 to complete the 3D calibration of the other camera.
   6. Setting up 3D tracking: Right-click on Camera Group > 3D Tracking, select all cameras, and click on the OK button to open the 3D tracking window.
   7. Apply mode matching tracking: Set Use Pattern Matching Tracking for both cameras. Manually click on the Thumb Tip point in the first frame.
   8. Start auto tracking: Click on the Auto Search button to begin automatic 3D tracking frame by frame.
   9. Complete other video tracking: Follow steps 3.3.6-3.3.8 to complete motion tracking for the other videos.
      NOTE: If the tracking points are lost during auto 3D tracking, select the row where points are lost, right-click, and select Discard Points From Here. Then, click on the points and the Auto Search button again.
4. Data export
   1. Creating 3D calculations: Right-click on Camera Group > New 3D Calculation, select All Cameras, and check Update Data Continuously and Store Data Explicitly in the "Create 3D Data" window. Update data and explicitly store data in a file. Click on the OK button to proceed.
   2. Export settings: Right-click the folder Containing All the Data > Export.
   3. Exporting data files: Click on the Export button to export a data file with a customized name (*.txt). Export the other data files in the same way.

4. Data analysis

1. Summarization of data
   1. Measure the spatial dispersion by recording the maximum value of the moving range on the X-, Y-, and Z-axes of the passive infrared reflective sphere on the participants' thumbnail cap (Figure 2C).
   2. Calculate the standard deviation and take the mean value. Store the data in Microsoft Office Excel files and calculate the mean ± standard deviation for graphing.
2. Analysis of data
   1. Assess the differences between conditions with and without the cannula by conducting independent samples t-tests (for data consistent with normal distribution) or rank sum tests (for data not consistent with normal distribution).
   2. Then, perform a two-factor, three-level analysis of variance to evaluate the stability of different lifting and inserting amplitudes. Set the alpha level at p < 0.05 and use the Statistical Package for data analysis to carry out all statistical analyses.

Effect of the cannula on the stability of the lifting and thrusting manipulation
Graphs were generated based on the data from one operator, as shown in Figure 3, Figure 4, and Figure 5. The horizontal axis in each figure represents time, and the vertical axis represents the position of the tracking point on the operator's thumb tip, recording the motion trail of this point. Two lines of different colors illustrate the motion trails with and without the cannula.

The ranges of motion during the lifting and thrusting manipulations in the X-axis, Y-axis, and Z-axis are shown in Figure 6. The X-axis and Y-axis represent the operator's motion deviation in the anterior-posterior and left-right directions, respectively. The closer the motion amplitude is to 0, the more stable the lifting and thrusting manipulation. The Z-axis represents the up-and-down motion deviation, which is the primary observation index in this experiment. The closer the motion amplitude is to the prescribed 15 mm, the better the stability of the manipulation. The stability of the three lifting and thrusting techniques along the X-axis was significantly improved with the use of the cannula compared to without it. As shown in Figure 6A, the range of motion for all three techniques was lower when using the cannula, and the differences were statistically significant. No significant differences were observed in the stability of the techniques along the Y-axis. As shown in Figure 6B, the range of motion with and without the cannula was similar, and the differences were not statistically significant. The stability of the three lifting and thrusting techniques along the Z-axis was significantly better when using the cannula. As shown in Figure 6C, the motion ranges for even lifting and thrusting, heavy thrusting with light lifting, and light thrusting with heavy lifting were all closer to the target amplitude of 15 mm when using the cannula compared to not using it. These differences were statistically significant.

In the figures, even lifting and thrusting, heavy thrusting with light lifting, and light thrusting with heavy lifting are labeled as "even," "thrust," and "lift," respectively. A "*" symbol above the bars in the charts indicates a statistically significant difference between the two bars (p < 0.05). In conclusion, this cannula improves the stability of lifting and thrusting manipulations in both the anterior-posterior direction and in controlling depth.

Impact of manipulation amplitudes on the stability control ability of the cannula
In this experiment, the researchers measured the lifting and thrusting manipulations with amplitudes of 5 mm, 10 mm, and 15 mm (up and down) following the insertion of a 20 mm needle into the material. The goal was to observe the ranges of motion along the X-axis, Y-axis, and Z-axis and to quantitatively analyze the spatial stability of different lifting and thrusting amplitudes.

Graphs based on the data from the operator are presented in Figures 7, Figure 8, and Figure 9. The horizontal axis represents time, and the vertical axis represents the position of the tracking point on the operator's thumb tip. Three lines of different colors represent the motion trails for the different amplitudes.

The ranges of motion on the X-axis and Y-axis for various lifting and thrusting amplitudes and techniques are shown in Figures 10A,B. The range of motion on these axes indicates the operator's motion deviation in the anterior-posterior and left-right directions. The closer the range of motion is to 0, the better the stability. Since the ranges of motion on the Z-axis do not directly reflect motion deviation, the researchers used the error rate (Actual value - Predicted value ÷ Actual value × 100%) to evaluate the deviation in the up and down directions. This is the primary observation index in the experiment, and the results are shown in Figure 10C. The closer the error rate is to 0, the better the stability. As shown in Figure 10A, for even lifting and thrusting, stability on the X-axis improved as the amplitude increased, with the differences being statistically significant. For heavy thrusting with light lifting and light thrusting with heavy lifting, stability at an amplitude of 15 mm was better than at 5 mm and 10 mm, with statistically significant differences. As shown in Figure 10B, the amplitude and type of manipulation did not have a significant effect on stability along the Y-axis, and the differences were not statistically significant. As shown in Figure 10C, the closer the error rate is to 0, the better the stability along the Z-axis. Manipulations at amplitudes of 10 mm and 15 mm had better stability than at 5 mm, with statistically significant differences.

In the figures, even lifting and thrusting, heavy thrusting with light lifting, and light thrusting with heavy lifting are labeled as "even," "thrust," and "lift," respectively. A "*" symbol above the bars in the charts indicates that the difference between each pair of bars is statistically significant (p < 0.05). In summary, the larger the manipulation amplitude, the greater the safety and stability in the anterior-posterior direction and depth. The cannula is most effective at improving the stability of lifting and thrusting manipulations when used with an amplitude of at least 10 mm.

Figure 1: Structure of the control cannula. (A) The cannula. It is hollow and has a sliding strip on one side. The scale range is marked next to the sliding strip, spanning 4 cm with 1 mm intervals. The lower end has a fixed stopper that limits the maximum insertion depth. The hollow part allows for the movement of the needle sleeve. During operation, the assistant hand holds the cannula, while the operating hand manipulates the needle sleeve to perform the lifting and thrusting action. (B) The needle sleeve. It is hollow and holds the disposable acupuncture needle. Two fixed stoppers at the lower end limit the lifting and thrusting movement, ensuring stability in the amplitude of the manipulations. The operator holds the needle sleeve for these actions. (C) An adjustable stopper. It has a sliding strip on the side, which fits into the cannula's sliding strip to set the minimum insertion depth. It has concave grooves to align with the fixed stopper on the needle sleeve. The stopper is positioned in the cannula, and after the needle sleeve is inserted, it is rotated 90 degrees to lock the sleeve in place for controlled manipulations. (D) Combination of the control cannula. The needle sleeve is inserted into the cannula, with the adjustable stopper fixed along the sliding strip of the cannula. (E) Sample of the assembled device. A disposable acupuncture needle is placed in the needle sleeve. The left-hand holds the cannula, while the right hand operates the needle sleeve for lifting and thrusting manipulations. Please click here to view a larger version of this figure.

Figure 2: Placement of the videography setup. (A) Camera settings. Two motion cameras are positioned on tripods in front of the operator's desk to capture the motion trails of the measured point. (B) Calibration settings. A 3D calibration stand is placed on the table to ensure accurate measurement of spatial positions. (C) X-, Y-, and Z-axes. Schematic diagram showing the spatial positions used in the analysis. Please click here to view a larger version of this figure.

Figure 3: Motion trail of even lifting and thrusting with and without the cannula. (A) Motion trail on the X-axis of even lifting and thrusting. The X-axis motion trail with and without the cannula is shown in two different colors. (B) Motion trail on the Y-axis of even lifting and thrusting. The Y-axis motion trail with and without the cannula is shown in two different colors. (C) Motion trail on the Z-axis of even lifting and thrusting. The Z-axis motion trail with and without the cannula is shown in two different colors. Please click here to view a larger version of this figure.

Figure 4: Motion trail of heavy thrusting with light lifting with and without the cannula. (A) Motion trail on the X-axis of heavy thrusting with light lifting. The X-axis motion trail with and without the cannula is shown in two different colors. (B) Motion trail on the Y-axis of heavy thrusting with light lifting. The Y-axis motion trail with and without the cannula is shown in two different colors. (C) Motion trail on the Z-axis of heavy thrusting with light lifting. The Z-axis motion trail with and without the cannula is shown in two different colors. Please click here to view a larger version of this figure.

Figure 5: Motion trail of light thrusting with heavy lifting with and without the cannula. (A) Motion trail on the X-axis of light thrusting with heavy lifting. The X-axis motion trail with and without the cannula is shown in two different colors. (B) Motion trail on the Y-axis of light thrusting with heavy lifting. The Y-axis motion trail with and without the cannula is shown in two different colors. (C) Motion trail on the Z-axis of light thrusting with heavy lifting. The Z-axis motion trail with and without the cannula is shown in two different colors. Please click here to view a larger version of this figure.

Figure 6: Range of motion for different manipulation methods with and without the cannula. (A) Range of motion on the X-axis for different manipulation methods. The X-axis motion range with and without the cannula is shown in two different colors. "Even" refers to even lifting and thrusting, "thrust" to heavy thrusting with light lifting, and "lift" to light thrusting with heavy lifting. An asterisk (*) indicates a statistically significant difference between the bars (p < 0.05). (B) Range of motion on the Y-axis for different manipulation methods. Same notations and interpretation as (A). (C) Range of motion on the Z-axis for different manipulation methods. Same notations and interpretation as (A). Please click here to view a larger version of this figure.

Figure 7: Motion trail of even thrusting and lifting with the cannula at different amplitudes. (A) Motion trail on the X-axis of even thrusting and lifting. The X-axis motion trail with different amplitudes is shown in three different colors. (B) Motion trail on the Y-axis of even thrusting and lifting. Same as (A) for the Y-axis. (C) Motion trail on the Z-axis of even thrusting and lifting. Same as (A) for the Z-axis. Please click here to view a larger version of this figure.

Figure 8: Motion trail of heavy thrusting with light lifting with the cannula at different amplitudes. (A) Motion trail on the X-axis of heavy thrusting with light lifting. The X-axis motion trail with different amplitudes is shown in three different colors. (B) Motion trail on the Y-axis of heavy thrusting with light lifting. Same as (A) for the Y-axis. (C) Motion trail on the Z-axis of heavy thrusting with light lifting. Same as (A) for the Z-axis. Please click here to view a larger version of this figure.

Figure 9: Motion trail of light thrusting with heavy lifting with the cannula at different amplitudes. (A) Motion trail on the X-axis of light thrusting with heavy lifting. The X-axis motion trail with different amplitudes is shown in three different colors. (B) Motion trail on the Y-axis of light thrusting with heavy lifting. Same as (A) for the Y-axis. (C) Motion trail on the Z-axis of light thrusting with heavy lifting. Same as (A) for the Z-axis. Please click here to view a larger version of this figure.

Figure 10: Range of motion for different manipulation methods and ranges. (A) Range of motion on the X-axis for different manipulation methods and ranges. The X-axis motion range for different amplitudes is shown in three different colors. "Even" refers to even lifting and thrusting, "thrust" to heavy thrusting with light lifting, and "lift" to light thrusting with heavy lifting. An asterisk (*) indicates a statistically significant difference between the bars (p < 0.05). (B) Range of motion on the Y-axis for different manipulation methods and ranges. Same notations and interpretation as (A). (C) Error rate on the Z-axis for different manipulation methods and ranges. Same notations and interpretation as (A). Please click here to view a larger version of this figure.

Supplementary File 1: STL file for fabricating the cannula. Please click here to download this File.

Supplementary File 2: STL file for fabricating the needle sleeve. Please click here to download this File.

Supplementary File 3: STL file for fabricating the adjustable stopper. Please click here to download this File.

This study innovatively designed a cannula to improve the stability and safety of acupuncture lifting and inserting manipulations and conducted experiments to evaluate its effectiveness. The researchers used 3D modeling for the structural design and white resin as the material for 3D printing. Compared to manufacturing a metal mold, 3D printing technology offers the advantages of lower cost and easier structural adjustments. Additionally, since the disposable needle is positioned sideways in the groove of the needle sleeve (Figure 2), there is no direct human contact with the needle during acupuncture, reducing the risk of infection in clinical use.

In this study, Simi Motion 3D, a three-dimensional motion tracking software, was employed to capture the movement amplitude of the lifting and thrusting manipulations. Compared with manual measurement using a ruler, tracking the position of the operator's fingers through 3D motion software provided more efficient and accurate measurements of the different depths in each lifting and thrusting movement. The analysis of coordinate data exported from the motion 3D software demonstrated that the needle cannula reduced errors in both the horizontal direction and the depth of lifting and inserting manipulations. The cannula was particularly effective for methods involving amplitudes of 10 mm or more. Clinically, errors in the horizontal direction can result in misplacement of the needle, leading to deviation from the targeted acupuncture point or causing additional pain to the patient. Errors in vertical orientation can alter the depth of needle penetration into subcutaneous tissue, potentially causing harm. For example, excessive depth at acupoints with shallow subcutaneous tissue or near vital organs and arteries could damage deep organs. This is especially concerning at acupoints like QiMen (LR14) in the 6^th intercostal space, Zhongfu (LU1) on the anterior chest wall, and Yunmen (LU2) near the subclavian fossa, all of which are close to the lungs²⁷. The needle cannula developed in this study can significantly reduce these errors, enhancing safety and minimizing the risk of medical accidents during acupuncture.

In the process of performing acupuncture, the safety and stability of the operation are among the most important factors affecting clinical efficacy, and the spatial stability of the operation depends entirely on the experience and proficiency of the operator, which is the most challenging aspect of learnin²⁸. In clinical practice, experienced practitioners can naturally apply techniques flexibly. However, in acupuncture efficacy experiments, it is more important to have a well-defined system of rules and mature control methods to strictly control variables, ensuring the validity and scientific rigor of the experiment^29,30,31. The cannula designed in this study helps limit the scope of the lifting and thrusting manipulation to address this need.

Moreover, acupuncture requires high technical precision and adherence to strict procedures, where operators must master a series of techniques from needle insertion to withdrawal. Acupuncture education emphasizes the stability of manipulation. Introducing new technology to quantify acupuncture techniques can make education more effective than traditional teaching methods^32,33. For acupuncture students and beginners, this project provides a tool to improve needling skills by training them to control the depth and position of manipulation.

However, the needle cannula designed in this study is limited to lifting and thrusting manipulation and cannot be used for other techniques, such as twisting manipulation. The cannula's utility could be significantly enhanced if its structure were adapted to support a wider range of acupuncture techniques.

None.

This work was supported by Budget Project of Shanghai Municipal Education Commission (Grant Number 2021LK099) and the National Natural Science Foundation of China (Grant Number 82174506).