A safe control method for the insertion depth of a cannulated wrist-ankle needle intervention

Abstract

The application relates to the technical field of TCM acupuncture auxiliary control, and discloses a safe control method for the insertion depth of a cannula type wrist-ankle needle intervention, which comprises the following steps: collecting skin surface deformation data through a flexible strain sensing array, inversely distributing normal contact force on the basis of a thin plate mechanics model, externally constraining and correcting the needle tip depth reconstructed by fiber strain integration, calculating and estimating the residual crossing time, dynamically generating time-adaptive micro-vibration detection parameters on the basis of the estimated residual crossing time, executing axial micro-vibration detection, weighting and fusing the elastic recovery coefficient and the propulsion resistance step characteristics, outputting the tissue level judgment result and the fusion confidence, and executing layered safety decision and controlling the sleeve electric control snap ring lock unit.

Description

Technical Field

[0001] This invention relates to the field of auxiliary control technology for traditional Chinese medicine acupuncture, specifically to a method for safe control of needle insertion depth in cannula-type wrist-ankle acupuncture intervention. Background Technology

[0002] Wrist-ankle acupuncture is a traditional Chinese medicine acupuncture method in which the needle is inserted into the superficial fascia layer under the skin. During the procedure, the needle tip must always remain within the superficial fascia layer and must not penetrate the deep fascia. Cannula-type wrist-ankle acupuncture intervention, which guides the needle into the target layer through an outer cannula, is a common implementation method for this procedure.

[0003] Existing methods for controlling needle insertion depth safety mainly fall into two categories. The first category is a tissue layer discrimination method based on light scattering signals combined with micro-vibration elastic detection. This method requires the needle to remain in the current layer for a sufficient time to perform reciprocating vibrations and collect elastic recovery signals. The second category is a needle tip depth correction method based on skin surface deformation field inversion, which can provide information on the current spatial position of the needle tip.

[0004] Both of the above methods have limitations in patients with thin body types. The superficial fascia layer thickness in these patients may be only 2 to 3 mm, leaving less than 1 mm of safe depth margin. Under these conditions, the available detection time window at normal needle insertion speed is extremely short, resulting in insufficient detection cycles and low confidence in the first type of method. The second type of method only reflects the current position of the needle tip and cannot predict changes in tissue properties directly in front of the needle tip, nor can it independently determine the actual distance to the deep fascia interface. Neither method can independently guarantee safe needle insertion depth under conditions of an ultra-thin superficial fascia layer. Summary of the Invention

[0005] This invention provides a method for safe control of needle insertion depth in cannulated wrist-ankle needle intervention, which solves the technical problems in related technologies such as lack of real-time depth perception and tissue layer recognition during the needle insertion process, and inability to trigger locking control in time before the needle tip approaches the lower boundary of the superficial fascia layer.

[0006] This invention discloses a method for safe control of needle insertion depth in cannulated wrist-ankle needle intervention, comprising:

[0007] The real-time sequence of needle tip vertical depth, corrected by external constraints, is obtained based on the skin surface deformation field inversion; the remaining crossing time is estimated based on the real-time sequence of needle tip vertical depth.

[0008] Based on the estimated remaining crossing time, time-adaptive micro-vibration detection parameters are dynamically generated. These time-adaptive micro-vibration detection parameters include the fusion weights of axial micro-vibration amplitude, vibration cycle number, propulsion resistance step characteristics, and elastic recovery coefficient.

[0009] The needle body is driven to perform axial micro-vibration according to the time-adaptive micro-vibration detection parameters. Elastic recovery characteristics and propulsion resistance change signals are collected, and the tissue level determination result and fusion confidence are output after weighted fusion.

[0010] The needle tip vertical depth, the tissue level determination result, and the fusion confidence level are input into the hierarchical safety decision logic, which outputs a lock-up control command and a needle insertion depth safety control record.

[0011] Furthermore, the real-time sequence of needle tip vertical depth obtained by inverting the skin surface deformation field and correcting for external constraints includes: acquiring in-plane tensile strain and normal displacement of the skin surface in real time during needle insertion using a flexible strain sensor array; inverting the in-plane tensile strain and normal displacement into the normal contact force distribution exerted by the needle on the surrounding tissue based on a thin plate mechanics model; using the normal contact force distribution as an external constraint condition to correct the needle tip depth obtained by integral reconstruction from the embedded fiber optic strain sensor in the needle, and outputting the real-time sequence of needle tip vertical depth corrected for external constraints.

[0012] Furthermore, the estimated remaining travel time The information is obtained by: within a sliding window of the real-time sequence of the needle tip's vertical depth. A least-squares linear fit is performed on each sampling point, and the resulting slope is used as the current needle insertion speed. Obtain the depth value of the lower boundary of the superficial fascia layer obtained from preoperative ultrasound measurement. ,Will Vertical depth value of the current needle tip The difference is taken as the remaining distance; the remaining distance is divided by the current needle advance speed to obtain... : ;

[0013] in, This represents the depth of the lower boundary of the superficial fascia layer. For the current moment The needle tip vertical depth value corrected by external constraints. For the current moment The needle insertion speed.

[0014] Furthermore, the time-adaptive micro-vibration detection parameters are generated according to the following rules: when season , , , ;when season: ;

[0015] in, To estimate the remaining travel time, To preset a sufficient threshold, To be the minimum execution threshold, Standard vibration amplitude, This represents the amplitude of axial micro-vibration. For the maximum allowable increment, For the standard number of loops, To minimize the number of vibration cycles, The weights for the step characteristics of propulsion resistance under standard conditions. , This represents the maximum adjustment amount for the weight.

[0016] Furthermore, when At this time, the micro-vibration detection step is skipped, and the fusion confidence level is set to a preset low value below the reliability threshold, so that the hierarchical security decision logic enters the conservative locking strategy.

[0017] Furthermore, the weighted fusion output of the organizational hierarchy determination result and fusion confidence score includes: extracting elastic recovery coefficients from the elastic recovery features. Extracting propulsion drag step characteristics from propulsion drag change signals ; regarding the step characteristics of propulsion resistance The mean normalization based on the range is obtained. According to fusion weight and right and Perform weighted fusion to output organizational hierarchy determination quantity : ;

[0018] in, The elastic recovery coefficient, The normalized propulsion drag step characteristics are shown below. The fusion weights for the elastic recovery coefficients, To advance the fusion weights of the drag step characteristics; when Exceeding the preset judgment threshold At that time, it was determined that the needle tip had entered the characteristic area of ​​the deep fascia layer; when No more than At that time, it was determined that the needle tip was still within the superficial fascia layer.

[0019] Furthermore, the elastic recovery coefficient Defined as ,in This represents the intensity recovery of the dual-wavelength light scattering signal during the retraction process after the needle body's micro-vibration propulsion. The propulsion amount is the intensity of the dual-wavelength light scattering signal during micro-vibration propulsion; the propulsion resistance step characteristic Defined as ,in For the first Propulsion resistance during each vibration cycle of propulsion. For the first The propulsion resistance during each vibration cycle; the range and mean benchmarks used for the normalization process were obtained by preoperative calibration and collection in the normal body area of ​​the same patient.

[0020] Furthermore, the fusion confidence level Defined as: ;

[0021] in, The confidence growth rate constant is pre-calibrated. This refers to the actual number of vibration cycles completed during this detection. This represents the signal-to-noise ratio of the elastic recovery signal in this detection.

[0022] Furthermore, the layered safety decision logic includes: when the distance between the needle tip vertical depth value, corrected by external constraints, and the lower boundary of the superficial fascia layer is less than a first safety threshold. When the distance is within the specified range, a locking command is sent directly; when the distance is within the specified range... With the second safety threshold Between and organizational hierarchy determination quantity Exceeding the preset judgment threshold When, send a lock command; when the fusion confidence level... Below the reliable threshold And the distance is less than When, lock is executed; when the fusion confidence level is... Below And the distance is greater than or equal to At the same time, reduce the needle insertion speed and increase the depth sampling frequency; among which , For the absolute safe distance boundary, This is for early warning of distance boundaries.

[0023] This invention discloses a safe control system for the insertion depth of a cannula-type wrist-ankle needle intervention, used to execute the above method, including:

[0024] The depth correction module is used to collect the in-plane tensile strain and normal displacement of the skin surface through a flexible strain sensor array, invert the normal contact force distribution based on the thin plate mechanical model, perform external constraint correction on the needle tip depth reconstructed by the embedded fiber optic strain sensor, and output the real-time sequence of needle tip vertical depth corrected by external constraint.

[0025] The time-travel calculation module is used to calculate the current needle insertion speed and remaining distance based on the real-time sequence of the needle tip vertical depth, and to obtain the estimated remaining time-travel.

[0026] The detection parameter generation module is used to dynamically generate time-adaptive micro-vibration detection parameters based on the estimated remaining crossing time.

[0027] The tissue level determination module is used to drive the needle body to perform axial micro-vibration according to the time-adaptive micro-vibration detection parameters, simultaneously collect elastic recovery characteristics and propulsion resistance change signals, and output the tissue level determination result and fusion confidence after weighted fusion.

[0028] The safety decision module is used to execute hierarchical safety decision logic based on the needle tip vertical depth value, the tissue level determination result and the fusion confidence level, send control commands to the cannula electronic control ring locking unit, and output needle insertion depth safety control records.

[0029] The present invention has the following beneficial effects.

[0030] Based on the thin plate mechanics model, the deformation field of the skin surface is inverted into the normal contact force distribution, and the fiber strain integral reconstruction result is corrected accordingly. This eliminates the systematic bias of tissue contact force on needle tip depth reconstruction and improves the estimation accuracy of needle tip vertical depth.

[0031] The remaining crossing time is estimated based on the real-time sequence of needle tip vertical depth corrected by external constraints, and the axial micro-vibration amplitude, vibration cycle number, and fusion weight are dynamically adjusted accordingly. When the available detection time window shortens, the single vibration amplitude is increased to improve the signal-to-noise ratio, the vibration cycle number is reduced to adapt to the time window, and the fusion weight of the propulsion drag step characteristics is increased to compensate for insufficient elastic recovery signal statistics, so that effective tissue level discrimination information can still be obtained within the limited time window.

[0032] By employing a hierarchical security decision-making logic, when the fusion confidence is sufficient, dual-source cross-validation is used with the needle tip vertical depth information and the organizational hierarchy judgment result; when the fusion confidence is insufficient, a conservative locking strategy is executed with the needle tip vertical depth value as the main criterion, thus avoiding the risk of incorrect judgment when the detection information is insufficient.

[0033] The synergistic effect of the above components enables this method to overcome the limitations of individual methods, even in patients with thin bodies and insufficient safety margins, and achieve safe control of needle insertion depth. Attached Figure Description

[0034] Figure 1 This is a flowchart of the method for safe control of needle insertion depth in cannulated wrist-ankle needle intervention provided in an embodiment of the present invention;

[0035] Figure 2 This is a schematic diagram showing the comparison between the real-time vertical depth sequence of the needle tip and the corrected value provided in an embodiment of the present invention.

[0036] Figure 3 This is a schematic diagram of the normal contact force correction amount at each sampling time provided in the embodiments of the present invention;

[0037] Figure 4 This is a schematic diagram comparing micro-vibration detection parameters under different estimated remaining crossing times provided in the embodiments of the present invention;

[0038] Figure 5 This is a schematic diagram comparing the drag weight and elasticity weight under different estimated remaining crossing times provided in the embodiments of the present invention;

[0039] Figure 6 This is a schematic diagram comparing the fusion result of the micro-vibration detection signal with the judgment threshold provided in the embodiment of the present invention;

[0040] Figure 7 This is a schematic diagram showing the comparison between fusion confidence and reliability threshold provided in an embodiment of the present invention;

[0041] Figure 8 This is a schematic diagram comparing key distance parameters for hierarchical security decision-making provided in an embodiment of the present invention;

[0042] Figure 9 This is a schematic diagram showing the comparison between the corrected needle tip depth and the critical depth of the superficial fascia layer during the needle insertion process, as provided in an embodiment of the present invention. Detailed Implementation

[0043] The subject matter described herein will now be discussed with reference to exemplary embodiments. It should be understood that these embodiments are discussed only to enable those skilled in the art to better understand and implement the subject matter described herein, and changes may be made to the function and arrangement of the elements discussed without departing from the scope of this specification. Various processes or components may be omitted, substituted, or added as needed in the examples. Furthermore, some features described in the examples may be combined in other examples.

[0044] At least one embodiment of the present invention discloses a method for safe control of needle insertion depth in cannulated wrist-ankle needle intervention, see [link to relevant documentation]. Figure 1 This includes the following steps:

[0045] Step 1: Obtain the real-time sequence of needle tip vertical depth corrected by external constraints based on skin surface deformation field inversion.

[0046] A flexible strain sensor array is used to collect in-plane tensile strain and normal displacement on the skin surface in real time during needle insertion. Based on a thin-plate mechanics model, the in-plane tensile strain and normal displacement are inverted into the normal contact force distribution exerted by the needle on the surrounding tissue. The normal contact force distribution is used as an external constraint to correct the needle tip depth obtained by the strain integral reconstruction of the embedded fiber optic cable, outputting a real-time sequence of needle tip vertical depth corrected by external constraints.

[0047] It should be noted that the aforementioned thin-plate mechanical model treats the skin and superficial tissue around the puncture point as an elastic thin plate subjected to concentrated forces, and uses Kirchhoff's thin-plate theory to establish a mapping relationship between in-plane strain, normal displacement, and normal contact force. Measurement data from a flexible strain sensor array is used as boundary conditions input to this mapping relationship to solve for the spatial distribution of the normal contact force. An embedded fiber optic strain sensor has multiple grating nodes distributed along the needle axis. The strain values ​​of each node are integrated to reconstruct the needle's deflection morphology and the spatial position of the needle tip. Since the fiber optic strain sensor's integral reconstruction is based only on the needle's own deformation and does not consider the contribution of external forces exerted by tissue on the deformation, the inverted normal contact force distribution is applied as a constraint condition to the integral reconstruction process to eliminate systematic biases caused by tissue contact forces, thus obtaining the needle tip vertical depth corrected by external constraints.

[0048] Step 2: Calculate the estimated remaining travel time.

[0049] Based on the real-time sequence of needle tip vertical depth corrected by external constraints, the sliding window is used to... sampling points Perform a least-squares linear fit and use the resulting slope as the current needle insertion speed. ,in This represents the number of sampling points within the sliding window. For the first The time corresponding to each sampling point For the first The vertical depth value of the needle tip corresponding to each sampling point, corrected by external constraints. This is the sampling point index. It retrieves the depth value of the lower boundary of the superficial fascia layer obtained from preoperative ultrasound measurements. ,Will Vertical depth value of the current needle tip The difference is taken as the remaining distance. The remaining distance is divided by the current needle advance speed to obtain the estimated remaining travel time. : ;

[0050] in, This refers to the depth of the lower boundary of the superficial fascia layer obtained from preoperative ultrasound measurement. For the current moment The needle tip vertical depth value corrected by external constraints. For the current moment The needle insertion speed, and The units are all millimeters. The unit is millimeters per millisecond, and the result is... The unit is milliseconds.

[0051] Step 3: Dynamically generate time-adaptive micro-vibration detection parameters based on the estimated remaining travel time.

[0052] Based on the estimated remaining travel time The execution parameters for axial micro-vibration detection are dynamically generated by driving the cannula to the needle body. The time-adaptive micro-vibration detection parameter set is defined as follows: ,in This represents the amplitude of axial micro-vibration. The number of vibration cycles, To increase the weight of resistance step characteristics in weighted fusion, Let be the weight of the elastic recovery coefficient in the weighted fusion, and The time-adaptive micro-vibration detection parameters are generated according to the following rules:

[0053] when season , , , ;

[0054] when season ;

[0055] in, The preset sufficient threshold corresponds to the sum of the time required to complete one round of detection and the safety margin time under the standard vibration amplitude and standard number of cycles; The minimum execution threshold corresponds to completion under conditions of increased vibration amplitude. The shortest time required for one vibration cycle; Standard vibration amplitude; This is the standard number of loops; The minimum number of vibration cycles required to satisfy the statistical distinguishability of the elastic recovery signal under conditions of increased vibration amplitude; This is the maximum permissible increment. The weights for the step characteristics of propulsion resistance under standard conditions; ; This represents the maximum adjustment amount for the weights; all of the above parameters are pre-calibrated constants.

[0056] In this embodiment of the application, in order to obtain effective organizational hierarchy information even when the estimated remaining traversal time is extremely short, when In this case, the micro-vibration detection step is skipped, and the fusion confidence level is set to a preset low value below the reliability threshold, allowing subsequent safety decisions to directly adopt a conservative locking strategy based on spatial location. This approach avoids erroneous judgments caused by forcibly performing incomplete detection within a very short time window.

[0057] Step 4: Perform time-adaptive micro-vibration detection and output tissue level determination results.

[0058] According to time-adaptive micro-vibration detection parameters The needle body is driven by a cannula to perform axial micro-vibration. Simultaneously, the elastic recovery characteristics and propulsion resistance variation signals of dual-wavelength light scattering signals are acquired. The elastic recovery coefficient is extracted from the elastic recovery characteristics. Extracting propulsion drag step characteristics from propulsion drag change signals The step characteristics of propulsion resistance. Perform mean normalization based on the range to obtain dimensionless values. This enables the normalized propulsion drag step characteristics to change. With dimensionless elastic recovery coefficient They have the same dimensional benchmark. According to the fusion weights and For elastic recovery coefficient and normalized propulsion drag step characteristics Perform weighted fusion to output organizational hierarchy determination quantity Organizational hierarchy determination results and fusion confidence level : ;

[0059] in, The weight of the elastic recovery coefficient in the weighted fusion. To increase the weight of resistance step characteristics in weighted fusion, The elastic recovery coefficient, The normalized propulsion resistance step characteristics are shown. Exceeding the preset judgment threshold At that time, it was determined that the needle tip had entered the characteristic area of ​​the deep fascia layer; Not exceeding the preset judgment threshold At that time, it was determined that the needle tip was still within the superficial fascia layer.

[0060] It should be noted that the above elastic recovery coefficient Defined as: ;

[0061] in, This represents the intensity recovery of the dual-wavelength light scattering signal during the retraction process after the needle body's micro-vibration propulsion. This represents the propulsion amount due to the intensity of the dual-wavelength light scattering signal during micro-vibration propulsion. The superficial fascia layer is soft and has a low elastic recovery coefficient, while the deep fascia layer is dense and has a high elastic recovery coefficient.

[0062] The above-mentioned propulsion and resistance step characteristics Defined as: ;

[0063] in, For the first Propulsion resistance during each vibration cycle of propulsion. For the first Propulsion resistance during each vibration cycle of propulsion. This serves as an index for the current oscillation period. The propulsion drag step characteristic occurs when the needle tip approaches the deep fascia interface. It has increased significantly.

[0064] It should be noted that the above-mentioned propulsion resistance step characteristics It reflects the change in resistance between adjacent vibration cycles, and its dimension is force. Elastic resilience coefficient This is the ratio of the two changes in light scattering intensity, and is a dimensionless value. It is used to achieve a step-like characteristic in propulsion drag. With elastic recovery coefficient Before weighted fusion, values ​​within the same range affect the step characteristics of propulsion and drag. After performing mean normalization based on the range, the dimensionless normalized propulsion drag step characteristics are obtained. The range and mean benchmarks used for normalization were obtained by preoperative calibration in the normal body region of the same patient to eliminate the influence of differences in the absolute value of tissue resistance between individuals.

[0065] The above fusion confidence level Defined as: ;

[0066] in, The confidence growth rate constant is pre-calibrated. This refers to the actual number of vibration cycles completed during this detection. This represents the signal-to-noise ratio of the elastic recovery signal in this detection. This represents an exponential function.

[0067] Step 5: Perform layered safety decisions and output needle insertion depth safety control records.

[0068] The externally constrained vertical depth of the needle tip, the tissue level determination result, and the fusion confidence level are input into the hierarchical safety decision logic. When the distance between the externally constrained vertical depth value and the lower boundary of the superficial fascia layer is less than the first safety threshold... At this time, a locking command is sent directly to the cannula electronically controlled retaining ring locking unit to stop needle advance. When the distance between the needle tip vertical depth value, corrected by external constraints, and the lower boundary of the superficial fascia layer is within the first safety threshold... With the second safety threshold Between, and the organizational hierarchy determination results show the organizational hierarchy determination quantity. Exceeding the preset judgment threshold When the confidence level is fused, a lock command is sent. Below the reliable threshold At that time, a conservative locking strategy is executed based on the distance relationship between the needle tip vertical depth value corrected by external constraints and the lower boundary of the superficial fascia layer. The output is a needle depth safety control record containing the needle tip vertical depth value corrected by external constraints, tissue level determination details, and locking decision basis.

[0069] It should be noted that the above First safety threshold The absolute safe distance boundary is determined based on the statistical distribution of superficial fascia thickness in thin-bodied patients. When the distance from the needle tip to the lower boundary of the superficial fascia is less than the first safe threshold... At this time, locking will be executed regardless of the organizational hierarchy determination result. Second security threshold. This refers to the warning distance boundary that requires cross-validation based on organizational hierarchy determination results.

[0070] In this embodiment of the application, the above-mentioned conservative locking strategy is: when the fusion confidence level Furthermore, the distance between the needle tip vertical depth value, corrected by external constraints, and the lower boundary of the superficial fascia layer is less than the second safety threshold. When, lock is executed; when the fusion confidence level is... However, the distance between the needle tip vertical depth value, corrected by external constraints, and the lower boundary of the superficial fascia layer is greater than or equal to the second safety threshold. At this time, reduce the needle insertion speed and increase the depth sampling frequency, and resume normal needle insertion only after sufficient confidence has been obtained in subsequent detection cycles. The reliability threshold is... This is a pre-defined confidence threshold. The conservative locking strategy ensures preventative protection based primarily on spatial location when detection information is insufficient.

[0071] On the other hand, the present invention also proposes a safe control system for the insertion depth of a cannula-type wrist-ankle needle intervention, comprising:

[0072] The depth correction module is used to collect in-plane tensile strain and normal displacement by a flexible strain sensor array attached to the skin surface around the puncture point, invert the normal contact force distribution based on the thin plate mechanics model, perform external constraint correction on the needle tip depth reconstructed by the embedded fiber optic strain sensor, and output a real-time sequence of needle tip vertical depth corrected by external constraints.

[0073] The travel time calculation module is used to calculate the current needle insertion speed and remaining distance based on the real-time sequence of needle tip vertical depth corrected by external constraints, and to obtain the estimated remaining travel time.

[0074] The detection parameter generation module is used to dynamically generate time-adaptive micro-vibration detection parameters for axial micro-vibration detection of the sleeve-driven needle body based on the estimated remaining crossing time.

[0075] The tissue level determination module is used to drive the needle body to perform axial micro-vibration according to the time-adaptive micro-vibration detection parameters, simultaneously collect elastic recovery characteristics and propulsion resistance change signals, and output the tissue level determination result and fusion confidence after weighted fusion.

[0076] The safety decision module is used to execute hierarchical safety decision logic based on the needle tip vertical depth value corrected by external constraints, the organizational level judgment result, and the fusion confidence level, send control commands to the sleeve electronic control ring locking unit, and output the needle insertion depth safety control record.

[0077] By way of example, the system proposed in this invention may also include various features and combinations thereof in the method embodiments, which will not be elaborated here.

[0078] This invention obtains a high-precision, externally constrained, real-time sequence of needle tip vertical depth through skin surface deformation field inversion. Based on this sequence, it calculates the estimated remaining penetration time and dynamically adjusts the axial micro-vibration amplitude, vibration cycle count, and fusion weight in the time-adaptive micro-vibration detection parameters. In ultra-thin superficial fascia layers, when the available detection time window is shortened, the insufficient elastic recovery signal statistics are compensated by increasing the single vibration amplitude to improve the signal-to-noise ratio, reducing the vibration cycle count to adapt to the time window, and increasing the fusion weight of the propulsion resistance step characteristics. This ensures that effective tissue level discrimination information can still be obtained within a limited time. When detection information is sufficient, dual-source cross-validation of the externally constrained needle tip vertical depth information and the tissue level determination result achieves high-confidence control. When detection information is insufficient, a conservative locking strategy is implemented using the externally constrained needle tip vertical depth value as the primary criterion. Therefore, this method overcomes the limitations of individual methods and achieves reliable and safe control of needle insertion depth, even in patients with extremely thin superficial fascia layers and insufficient safety margins.

[0079] See Figures 2-9 The following application examples are proposed:

[0080] A hospital's acupuncture department performed wrist-ankle acupuncture on a thin female patient (patient A). Preoperative ultrasound evaluation showed that the superficial fascia layer thickness at the puncture site on patient A's forearm was only 2.4 mm, and the lower boundary of the superficial fascia layer was [missing information]. The thickness is 3.1mm, which falls under the category of extremely thin shallow fascia layers with insufficient safety margin. A flexible strain sensor array has been attached around the puncture point. The needle fiber optic strain sensor, the cannula dual-wavelength light scattering sensor, and the advance resistance sensor have all been initialized and calibrated. The cannula electronically controlled retaining ring locking unit is in standby mode. System preset parameters include: , , , , , .

[0081] The needle insertion operation is initiated under the unified timing of the processor, and the following steps are executed in sequence.

[0082] After needle insertion is initiated, the flexible strain sensor array continuously acquires the in-plane tensile strain and normal displacement of the skin surface. Based on the thin-plate mechanics model (Kirchhoff's thin-plate theory), the above measurements are inverted into the normal contact force distribution of the needle body on the surrounding tissue. This is then used as an external constraint to correct the needle tip position obtained from the integral reconstruction of the fiber optic strain sensor, outputting a real-time sequence of needle tip vertical depth corrected by external constraints. The table below shows representative sampling point data for patient A during the initial stage of needle insertion.

[0083] Table 1. Real-time sequence of needle tip vertical depth corrected by external constraints (representative sampling points)

[0084] As shown in Table 1, the normal contact force correction systematically reduces the depth value by approximately 0.04 to 0.07 mm, and the corrected sequence more accurately reflects the actual position of the needle tip within the superficial fascia layer.

[0085] Based on the corrected depth real-time sequence output in step 1, the current time... (150ms) before the sliding window The slope obtained by performing a least-squares linear fit on each sampling point is the current needle insertion speed. .by Subtract current depth The remaining distance is calculated, and then divided by the current speed to obtain the estimated remaining travel time. .

[0086] Table 2. Calculation process for estimated remaining travel time

[0087] greater than At this point, the detection time window is relatively ample, and the system enters the standard parameter configuration branch.

[0088] Based on the results obtained in step 2 The system generates a set of time-adaptive micro-vibration detection parameters under standard conditions. That is, using standard vibration amplitude Standard number of cycles and standard weight combinations. The table below records the generation results of this detection parameter, and compares them with the ultrathin window compression case (assuming that the needle insertion speed will subsequently increase, leading to...). (The data will be compared with the data falling within the compression range) to demonstrate the actual effect of dynamic adjustment.

[0089] Table 3 Time-adaptive micro-vibration detection parameters at different times Generation results in the following cases

[0090] In the case of extremely short time ( Micro-vibration detection was skipped, and the fusion confidence level was directly set to below 1. The preset low value will lead to a shift to a conservative locking strategy in subsequent security decisions.

[0091] Based on the parameter set generated this time ( , , , The cannula drives the needle body to perform six axial micro-vibration cycles. Simultaneously, dual-wavelength light scattering elastic recovery characteristics and propulsion resistance variation signals are acquired to extract the elastic recovery coefficient. and propulsion resistance step characteristics ,right After performing mean normalization based on the range, we get Calculated according to the fusion formula And calculate the fusion confidence. .

[0092] Table 4 Results of Micro-vibration Detection Signal Extraction and Fusion

[0093] Below The needle tip was determined to still be within the superficial fascia layer; Higher than The judgment in this case is credible.

[0094] The outputs from steps 1 to 4 are fed into the hierarchical security decision logic. The current corrected tip depth is 0.95mm, and the distance... The remaining distance is 2.15mm, which is much greater than And the confidence level is integrated. The tissue level determination result showed that the needle tip was still in the superficial fascia layer. The system determined it to be in a safe state, did not trigger the lock, continued to advance the needle and output the control record for this round.

[0095] Table 5. Layered safety decision results and needle insertion depth safety control records

[0096] Throughout the process, the data stream originates from the raw measurements of the flexible strain sensor array and fiber optic sensor. Through thin-plate mechanical model inversion and external constraint correction, a more accurate real-time sequence of needle tip vertical depth is generated. This sequence is then transformed into an estimated remaining crossing time via sliding window least-squares fitting, which in turn drives the dynamic generation of detection parameters. These detection parameters guide the execution of micro-vibrations. Light scattering signals and propulsion resistance signals are normalized and fused to output tissue layer determination quantities and confidence levels. Finally, the depth information, layer determination results, and confidence levels are cross-validated within a hierarchical safety decision-making logic, forming control instructions with clear evidence and a complete record. The output of each step directly serves as the input for the next step, ensuring a continuous and logically self-consistent data link. This achieves reliable and safe control of needle insertion depth even when the patient's superficial nail fascia layer has a safety margin of less than 1 mm.

[0097] The embodiments of the present invention have been described above. However, the embodiments are not limited to the specific implementation methods described above. The specific implementation methods described above are merely illustrative and not restrictive. Those skilled in the art can make more equivalent embodiments under the guidance of the present embodiments, and all of them are within the protection scope of the present embodiments.

Claims

1. A method for safe control of needle insertion depth in cannulated wrist-ankle acupuncture intervention, characterized in that, Includes the following steps: Real-time sequence of needle tip vertical depth, corrected by external constraints, is obtained based on skin surface deformation field inversion; The remaining crossing time is estimated based on the real-time sequence of the needle tip vertical depth. Based on the estimated remaining crossing time, time-adaptive micro-vibration detection parameters are dynamically generated. These time-adaptive micro-vibration detection parameters include the fusion weights of axial micro-vibration amplitude, vibration cycle number, propulsion resistance step characteristics, and elastic recovery coefficient. The needle body is driven to perform axial micro-vibration according to the time-adaptive micro-vibration detection parameters. Elastic recovery characteristics and propulsion resistance change signals are collected, and the tissue level determination result and fusion confidence are output after weighted fusion. The needle tip vertical depth, the tissue level determination result, and the fusion confidence level are input into the hierarchical safety decision logic, which outputs a lock-up control command and a needle insertion depth safety control record.

2. The method for safe control of needle insertion depth in a cannula-type wrist-ankle needle intervention according to claim 1, characterized in that, The real-time sequence of needle tip vertical depth obtained by inverting the skin surface deformation field and correcting for external constraints includes: The in-plane tensile strain and normal displacement of the skin surface during needle insertion are collected in real time using a flexible strain sensor array. Based on the thin plate mechanics model, the in-plane tensile strain and normal displacement are inverted into the normal contact force distribution exerted by the needle on the surrounding tissue. The normal contact force distribution is used as an external constraint condition to correct the needle tip depth obtained by integral reconstruction from the embedded fiber optic strain sensor in the needle, and the real-time sequence of needle tip vertical depth corrected by external constraints is output.

3. The method for safe control of needle insertion depth in cannulated wrist-ankle acupuncture intervention according to claim 1, characterized in that, The estimated remaining travel time Obtain it through the following methods: Within the sliding window of the real-time sequence of vertical depth of the needle tip A least-squares linear fit is performed on each sampling point, and the resulting slope is used as the current needle insertion speed. Obtain the depth value of the lower boundary of the superficial fascia layer obtained from preoperative ultrasound measurement. ,Will Vertical depth value of the current needle tip The difference is taken as the remaining distance; the remaining distance is divided by the current needle advance speed to obtain... : ； in, This represents the depth of the lower boundary of the superficial fascia layer. For the current moment The needle tip vertical depth value corrected by external constraints. For the current moment The needle insertion speed.

4. The method according to claim 1, characterized in that, The time-adaptive micro-vibration detection parameters are generated according to the following rules: when season , , , ; when season: ； in, To estimate the remaining travel time, To preset a sufficient threshold, To be the minimum execution threshold, Standard vibration amplitude, This represents the amplitude of axial micro-vibration. For the maximum allowable increment, For the standard number of loops, To minimize the number of vibration cycles, The weights for the propulsion resistance step characteristic under standard conditions. , This represents the maximum adjustment amount for the weight.

5. The method for safe control of needle insertion depth in a cannula-type wrist-ankle needle intervention according to claim 4, characterized in that, when At this time, the micro-vibration detection step is skipped, and the fusion confidence level is set to a preset low value below the reliability threshold, so that the hierarchical security decision logic enters the conservative locking strategy.

6. The method for safe control of needle insertion depth in cannulated wrist-ankle needle intervention according to claim 1, characterized in that, The weighted fusion output includes the organizational hierarchy determination result and fusion confidence level, including: Extracting elastic recovery coefficients from elastic recovery characteristics Extracting propulsion drag step characteristics from propulsion drag change signals ; regarding the step characteristics of propulsion resistance The mean normalization based on the range is obtained. According to fusion weight and right and Perform weighted fusion to output organizational hierarchy determination quantity : ； in, The elastic recovery coefficient, The normalized propulsion drag step characteristics are shown below. The fusion weights for the elastic recovery coefficients, To advance the fusion weights of the drag step characteristics; when Exceeding the preset judgment threshold At that time, it was determined that the needle tip had entered the characteristic area of ​​the deep fascia layer; when No more than At that time, it was determined that the needle tip was still within the superficial fascia layer.

7. The method for safe control of needle insertion depth in a cannula-type wrist-ankle needle intervention according to claim 6, characterized in that, The elastic recovery coefficient Defined as ,in This represents the intensity recovery of the dual-wavelength light scattering signal during the retraction process after the needle body's micro-vibration propulsion. The propulsion amount is the intensity of the dual-wavelength light scattering signal during micro-vibration propulsion; the propulsion resistance step characteristic Defined as ,in For the first Propulsion resistance during each vibration cycle of propulsion. For the first The propulsion resistance during each vibration cycle; the range and mean benchmarks used for the normalization process were obtained by preoperative calibration and collection in the normal body area of ​​the same patient.

8. The method for safe control of needle insertion depth in a cannula-type wrist-ankle needle intervention according to claim 1, characterized in that, The fusion confidence level Defined as: ； in, The confidence growth rate constant is pre-calibrated. This refers to the actual number of vibration cycles completed during this detection. This represents the signal-to-noise ratio of the elastic recovery signal in this detection.

9. The method for safe control of needle insertion depth in a cannula-type wrist-ankle needle intervention according to claim 1, characterized in that, The layered security decision-making logic includes: When the distance between the needle tip vertical depth value, corrected by external constraints, and the lower boundary of the superficial fascia layer is less than the first safety threshold... When the distance is within the specified range, a locking command is sent directly; when the distance is within the specified range... With the second safety threshold Between and organizational hierarchy determination quantity Exceeding the preset judgment threshold When, send a lock command; when the fusion confidence level... Below the reliable threshold And the distance is less than When, lock is executed; when the fusion confidence level is... Below And the distance is greater than or equal to At the same time, reduce the needle insertion speed and increase the depth sampling frequency; among which , For the absolute safe distance boundary, This is for early warning of distance boundaries.

10. A safe control system for the insertion depth of a cannula-type wrist-ankle acupuncture intervention, used to execute the safe control method for the insertion depth of a cannula-type wrist-ankle acupuncture intervention as described in any one of claims 1 to 9, characterized in that, include: The depth correction module is used to collect the in-plane tensile strain and normal displacement of the skin surface through a flexible strain sensor array, invert the normal contact force distribution based on the thin plate mechanical model, perform external constraint correction on the needle tip depth reconstructed by the embedded fiber optic strain sensor, and output the real-time sequence of needle tip vertical depth corrected by external constraint. The time-travel calculation module is used to calculate the current needle insertion speed and remaining distance based on the real-time sequence of the needle tip vertical depth, and to obtain the estimated remaining time-travel. The detection parameter generation module is used to dynamically generate time-adaptive micro-vibration detection parameters based on the estimated remaining crossing time. The tissue level determination module is used to drive the needle body to perform axial micro-vibration according to the time-adaptive micro-vibration detection parameters, simultaneously collect elastic recovery characteristics and propulsion resistance change signals, and output the tissue level determination result and fusion confidence after weighted fusion. The safety decision module is used to execute hierarchical safety decision logic based on the needle tip vertical depth value, the tissue level determination result and the fusion confidence level, send control commands to the cannula electronic control ring locking unit, and output needle insertion depth safety control records.

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