Efficient intelligent feedback bone cutting device and method based on multi-laser monitoring

Abstract

The invention discloses an efficient intelligent feedback bone cutting device and method based on multi-laser monitoring, and the device comprises a sample table for fixing a to-be-cut bone, a composite laser cutting module for cutting the to-be-cut bone, and a laser flow measurement module for monitoring and adjusting the water flow state. The laser density measurement module is used for measuring the density and the laser absorptivity of the bone to be cut in a non-contact manner; the distance laser ranging module is used for measuring the distance between a cutting laser head and a cutting surface; the temperature detector is directly aligned with the cutting area and used for monitoring the temperature of a cutting point in real time; the ultrasonic thickness gauge is used for measuring the thicknesses of different positions of the cut bone; the indication light source is used for indicating a laser cutting position and assisting in positioning; the computer controller is used for data acquisition, processing and closed-loop control; according to the invention, accurate presetting of composite laser parameters is realized through analysis of skeleton features, high-precision cutting of different skeletons is carried out, and monitoring and key parameter detection of the skeletons and the cutting process thereof are carried out.

Description

Technical Field

[0001] The present invention belongs to the field of laser bone cutting medical technology, and specifically relates to a high-efficiency intelligent feedback bone cutting device and method based on multi-laser monitoring. Background Art

[0002] Currently, bone cutting in forensic pathology craniotomy and other operations mainly relies on mechanical tools such as oscillating saws, circular saws, wire saws, osteotome and drill bits. Although these traditional mechanical cutting methods are widely used, they have significant inherent defects: First, during the mechanical sawing process, the direct contact between the saw blade and the bone will inevitably cause a certain degree of damage to the surrounding tissue. Second, the accuracy of mechanical sawing is usually limited to the millimeter level, making it difficult to achieve complex curved surfaces or minimally invasive fine cutting. In addition, the mechanical sawing process requires medical staff to exert a lot of force, which increases their physical exertion. At the same time, the harsh noise generated by high-speed mechanical tools during operation will cause a certain amount of psychological pressure on the surgical team. In addition, the control of cutting depth, angle, and speed is highly dependent on the surgeon's experience and feel, and the controllability and consistency are poor.

[0003] Laser osteotomy is an innovative technology in modern medicine. It utilizes the photothermal effect generated by the interaction of laser light with human tissue to achieve precise bone cutting. Lasers offer high energy concentration and directionality, enabling complex surgical procedures to be performed under minimally invasive conditions. Compared to traditional mechanical sawing, lasers achieve precise cutting without touching tissue, minimizing damage to surrounding tissue. Laser osteotomy can achieve micron-level precision, making it particularly important for surgeries requiring delicate manipulation.

[0004] The existing laser bone cutting technology has the following main problems: First, the stability and accuracy of the cutting process need to be improved. During the cutting process, the existing technology is often unable to adjust according to the real-time state of the bone due to the fixed laser parameters, resulting in reduced cutting accuracy and even incomplete or over-cutting. Second, the cutting efficiency is low. Currently, a single-beam laser is mainly used for point-by-point scanning cutting, which is much slower than mechanical sawing and cannot meet clinical requirements for cutting efficiency. Third, there is a lack of real-time monitoring. Existing systems generally lack the ability to monitor the cutting depth and bone surface temperature in real time and in situ. The operator cannot dynamically adjust the parameters based on real-time feedback. Fourth, the scope of application is limited. Existing technologies can often only cut specific types of bones, and their adaptability to the complex and changing needs of orthopedic surgery is poor. Summary of the Invention

[0005] In order to solve the problems existing in the above-mentioned prior art, the purpose of the present invention is to provide a high-efficiency intelligent feedback bone cutting device and method based on multi-laser monitoring. By analyzing the characteristics of bones, accurate preset of composite laser parameters can be achieved, and high-precision cutting of different bones can be carried out, and the bones and their cutting process can be monitored and key parameters detected.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A high-efficiency intelligent feedback bone cutting device based on multi-laser monitoring includes: a sample table 1 for fixing the bone to be cut, a composite laser cutting module for cutting the bone to be cut, a laser flow measurement module for monitoring and adjusting the water flow state, a laser density measurement module for non-contact measurement of the density of the bone to be cut and the laser absorption rate, and a distance laser ranging module for measuring the distance between the cutting laser head and the cutting surface; a temperature detector 10 installed on the side of the sample table 1 and directly aimed at the cutting area for real-time monitoring of the cutting point temperature; an ultrasonic thickness gauge 15 installed on the side of the sample table 1 for measuring the thickness of different positions of the cut bone; an indicating light source 5 for indicating the laser cutting position and assisting positioning; and a computer controller 19, which includes a central processing unit and a memory for data acquisition, processing and closed-loop control.

[0008] The composite laser cutting module includes an infrared laser 2, an ultraviolet laser 3, a first beam splitter 4-1, a second beam splitter 4-2, a first lens 6-1, a second lens 6-2, a third lens 6-3, a first reflective galvanometer 7-1, a second reflective galvanometer 7-2 and a cutting laser head 18;

[0009] The infrared laser emitted by the infrared laser 2 is divided into four beams of light through the second beam splitter 4-2: the first beam of light enters the laser flow measurement device 11 through the fourth lens 6-4, the front end of the laser flow measurement device 11 is connected to the water flow protection device 13, and the flow detector 14 is installed on the water flow protection device 13, and the flow detector 14 is located on one side of the sample stage 1; the fourth lens 6-4, the laser flow measurement device 11, the water flow protection device 13 and the flow detector 14 together constitute a laser flow measurement module; the second beam of light enters the laser density measurement device 12 through the fifth lens 6-5, and the front end of the laser density measurement device 12 is connected to the water flow protection device 13. The end is connected to the laser density measurement detector 8; the fifth lens 6-5, the laser density measurement device 12 and the laser density measurement detector 8 together constitute a laser density measurement module; the third beam of light enters the laser ranging device 16, the front end of the laser ranging device 16 is connected to the laser ranging detector 17, the laser ranging detector 17 is tightly integrated with the cutting laser head 18, and the laser ranging device 16 and the laser ranging detector 17 together constitute a laser ranging module; the fourth beam of light serves as the main cutting beam, which is scanned and focused by the first reflecting galvanometer 7-1 and the second lens 6-2, and then acts directly on the bone to be cut through the cutting laser head 18;

[0010] The ultraviolet laser emitted by the ultraviolet laser 3 is divided into two beams of light by the first beam splitter 4-1. The first beam of light passes through the laser-induced breakdown energy spectrum device 9, which is used to excite and analyze the bone plasma spectrum in real time during the cutting process and monitor changes in the nitrogen content; the second beam of light serves as an auxiliary cutting beam, which is scanned and focused by the first lens 6-1, the second reflective galvanometer 7-2 and the third lens 6-3, and then directly acts on the bone to be cut through the cutting laser head 18; all detectors and lasers are connected to the computer controller 19.

[0011] All components except the computer controller 19 are placed in a protective cover 20 , and a sound insulation layer is provided in the protective cover 20 to reduce working noise.

[0012] The infrared laser 2 is an Nd:YAG laser with a wavelength of 1064nm and an output power range of 5-50W. This wavelength has a moderate absorption rate for hydroxyapatite (the primary inorganic component of bone), effectively generating a photothermal effect to achieve bone cutting. Its longer wavelength also allows for a deep penetration into tissue, making it suitable as the primary cutting beam for efficient bone removal. Nd:YAG laser technology is mature, with high power stability and a wide adjustable range, meeting the needs of cutting bones of varying densities.

[0013] The ultraviolet laser 3 is an all-solid-state laser with a wavelength of 355nm and an output power range of 1-10W. This wavelength ultraviolet laser has the characteristics of high photon energy and low thermal effect. Its absorption rate for organic tissue is much higher than that of infrared laser, which can achieve more "cold" fine cutting and surface treatment, reducing the risk of thermal damage and carbonization. At the same time, it can also be used to stimulate laser-induced breakdown spectroscopy (LIBS), which can effectively stimulate elements in bones and soft tissues to produce characteristic spectral signals, which is the key to real-time cutting endpoint monitoring. The all-solid-state design has a compact structure, high reliability, and easy maintenance.

[0014] The bone cutting method of the high-efficiency intelligent feedback bone cutting device based on multi-laser monitoring comprises the following steps:

[0015] Step 1: Place the bone to be cut on the sample stage 1 according to its characteristics, calibrate the direction, and ensure that the normal direction of the bone surface to be cut is consistent with the main optical axis direction of the cutting laser head 18;

[0016] Step 2: Under the control of the computer controller 19, the ultrasonic thickness gauge 15 is moved to the initial cutting position. The thickness data H of the bone to be cut at the cutting position is measured point by point along the planned cutting path at a preset sampling interval using the ultrasonic thickness gauge 15. The measured thickness data is recorded and stored in the memory of the computer controller 19;

[0017] Step 3: Based on the thickness data H, the positions where the thickness change rate ΔH is greater than a preset threshold are segmented, and the segmentation information, i.e., the starting point, end point, and average thickness of each segment, is recorded in the memory of the computer controller 19;

[0018] Step 4: The computer controller 19 turns on the infrared laser 2 and controls the laser density measurement module to output a low-power infrared laser. The laser density measurement detector 8 obtains the bone density ρ and laser absorption rate α of the current area through non-contact measurement. The computer controller 19 calculates the power P of the infrared main cutting laser of the segment based on the measured bone density ρ and laser absorption rate α of the current area, combined with the average thickness information of the current segment:

[0019] P=k·ρ·α

[0020] Where k is the power coefficient; ρ is the bone density of the current area; α is the laser absorption rate;

[0021] Step 5: Move the cutting laser head 18 to the starting section of the first segment, start the laser distance measurement module, measure the distance d between the cutting laser head 18 and the cutting surface, and adjust the height of the cutting laser head 18 according to the distance measurement result to ensure that the working distance is stable within the preset optimal focal depth range;

[0022] Step 6: After confirming that the cutting laser head height meets the requirements, output high-power infrared laser for cutting, and at the same time start the temperature detector 10 to monitor the cutting point temperature in real time;

[0023] Step 7: Based on the bone density ρ and laser absorption rate α data of the current region obtained in step 4, as well as the thickness data of the current segment, the computer controller 19 calculates and sets the initial laser parameters, and the computer controller 19 drives the infrared main cutting beam to scan and cut along the preset path;

[0024] Step 8: During the cutting process, the water flow protection device 13 is turned on to supply cooling water to the cutting area. The water flow rate is proportional to the current infrared laser power. At the same time, the laser flow measurement module is turned on to monitor and adjust the water flow status at different positions. The computer controller 19 fine-tunes the output of the water flow protection device 13 based on the flow feedback to ensure a stable cooling effect.

[0025] Step 9: Monitor the data of the temperature detector 10 in real time. To prevent carbonization of the cut surface due to excessive temperature, when the temperature approaches the temperature safety threshold, reduce the laser power density P and increase the water flow rate to cool down. The water flow adjustment formula is:

[0026] Q new =Q0(1+β)

[0027] Among them, Q new is the adjusted water flow rate, Q0 is the current water flow rate, and β is the water flow adjustment coefficient, which is determined according to the temperature rise rate and amplitude;

[0028] If the temperature is lower than the temperature efficiency threshold, the working efficiency will decrease and the power density needs to be increased. The power adjustment formula is:

[0029] P new =P0(1+γ)

[0030] Among them, P new is the laser power after adjustment, P0 is the current laser power, and γ is the power adjustment coefficient;

[0031] Step 10: The computer controller 19 calculates the cutting depth h in real time using the thermal model based on the laser cutting parameters and the measured bone thickness:

[0032]

[0033] Where H is the total bone thickness; E is the laser energy density; t is the cutting time; D is the thermal diffusivity;

[0034] When the cutting depth h reaches 95% of the total thickness H, the infrared laser 2 is turned off and the ultraviolet laser 3 is turned on; the water flow rate at this time is adjusted to be proportional to the ultraviolet laser power; at the same time, the laser-induced breakdown spectroscopy device 9 is started to perform real-time measurement and spectrum analysis of the plasma generated in the cutting area, focusing on monitoring the intensity of the characteristic spectrum line of the nitrogen element. When the intensity of the characteristic spectrum line of the nitrogen element exceeds 5 times the standard deviation of the baseline, the cutting of the area is determined to be complete, and the ultraviolet laser 3 and the water flow protection device 13 are immediately turned off;

[0035] Step 11: The computer controller 19 controls the cutting laser head 18 to move to the starting section of the second segment, and repeats steps 4 to 10 until the cutting of the second segment is completed;

[0036] Step 12: After all segments are cut, all devices are turned off and the cut bone samples are removed from the sample stage 1.

[0037] The sampling interval ranges from 1 to 10 mm. The lower limit of 1 mm allows for precise capture of sharp changes in bone thickness over short distances (such as at sutures, hole edges, or thin bone areas), ensuring the accuracy of subsequent segmentation. The upper limit of 10 mm is suitable for larger bone areas with gentle thickness variations, effectively balancing measurement accuracy and scanning efficiency, avoiding unnecessary time consumption. This dynamically adjustable sampling interval enables the osteotomy device to intelligently adapt to the complex geometric features of different skeletal anatomical sites.

[0038] The temperature safety threshold is 45°C. Sustained exposure to temperatures above 50-60°C can cause irreversible protein denaturation and carbonization in bone tissue, significantly impacting the quality of the cut surface and its healing potential. This 45°C setting provides ample safety margin, effectively preventing local hotspots from reaching harmful temperatures during the real-time dynamic process, ensuring maximum tissue viability on the cut surface and minimizing areas of thermal necrosis.

[0039] The temperature efficiency threshold is 40°C. A temperature in the cutting zone that is too low typically means that laser energy isn't effectively absorbed by bone tissue and converted into a cutting effect, resulting in low energy utilization. This 40°C threshold triggers a power boost, preventing continuous cutting in the inefficient zone and significantly improving overall cutting efficiency while ensuring safety.

[0040] The multi-laser system of this invention can simultaneously utilize lasers of different wavelengths, optimizing laser parameters for different bone locations and densities, enabling selective cutting. This provides more flexible surgical options, shortens operative time, and improves surgical efficiency. Combined with a highly efficient intelligent feedback system, laser parameters can be adjusted in real time, ensuring stability and precision during the procedure.

[0041] The efficient intelligent feedback bone cutting technology with multi-laser monitoring is suitable for various types of pathological cutting analysis.

[0042] Compared with the prior art, the present invention has at least the following beneficial technical effects:

[0043] 1) Efficient cutting is achieved through multi-wavelength laser collaboration, intelligent parameter optimization, and closed-loop control;

[0044] 2) It has the ability to select accurate parameters in real time, perform online in-situ monitoring and dynamic feedback control, which greatly improves the intelligent level of the cutting process;

[0045] 3) The cutting process is automated, easy to operate, and requires no operator input;

[0046] 4) No splash, no pollution, and the sound insulation design inside the protective cover effectively reduces working noise;

[0047] 5) High safety, no contact during the cutting process, avoiding mechanical damage to bones and surrounding soft tissues, real-time temperature monitoring to prevent carbonization of bone tissue, and accurate endpoint judgment to effectively prevent damage to underlying important tissues;

[0048] 6) Laser cutting has high precision and small heat-affected zone, and does not require a large number of instruments and incisions;

[0049] 7) The relatively quiet, clean surgical process without violent mechanical movements can reduce the psychological impact on the operator.

[0050] The method of the present invention can rapidly select composite laser parameters based on characteristic parameters such as bone density and absorptivity, resulting in refined cutting parameters tailored to different bones and bone states. This allows for automated, highly secure bone cutting. The cutting process enables real-time measurement of information such as composition, temperature, and thickness, and can be adapted to various environments, including water baths and air cooling. It is pollution-free, noise-free, and harmless to other tissues. This method is applicable not only to bone cutting in forensic and medical engineering fields, but also to other fields, including cutting other uniform materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 It is a high-efficiency intelligent feedback bone cutting device based on multi-laser monitoring.

[0052] Figure 2 This is a flow chart of the efficient intelligent feedback osteotomy method based on multi-laser monitoring.

[0053] Figure 3 This is a cross-sectional morphology of the bone.

[0054] In the accompanying drawings: 1. Sample stage; 2. Infrared laser; 3. Ultraviolet laser; 4-1. First beam splitter; 4-2. Second beam splitter; 5. Indicator light source; 6-1. First lens; 6-2. Second lens; 6-3. Third lens; 6-4. Fourth lens; 6-5. Fifth lens; 7-1. First reflecting galvanometer; 7-2. Second reflecting galvanometer; 8. Laser density detector; 9. Laser induced breakdown spectroscopy device; 10. Temperature detector; 11. Laser flow measurement device; 12. Laser density measurement device; 13. Water flow protection device; 14. Flow detector; 15. Ultrasonic thickness gauge; 16. Laser distance measuring device; 17. Laser distance measuring detector; 18. Cutting laser head; 19. Computer controller; 20. Protective cover. DETAILED DESCRIPTION

[0055] In order to make the purpose and technical solution of the present invention clearer and easier to understand, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. The specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0056] like Figure 1 As shown, the present invention provides a high-efficiency intelligent feedback bone cutting device based on multi-laser monitoring, comprising:

[0057] Sample stage 1: used to fix the bone to be cut.

[0058] Composite laser cutting module: includes infrared laser 2, ultraviolet laser 3, first beam splitter 4-1, second beam splitter 4-2, first lens 6-1, second lens 6-2, third lens 6-3, first reflective galvanometer 7-1, second reflective galvanometer 7-2 and cutting laser head 18;

[0059] The infrared laser emitted by the infrared laser 2 is divided into four beams of light through the second beam splitter 4-2: the first beam of light enters the laser flow measurement device 11 through the fourth lens 6-4, the front end of the laser flow measurement device 11 is connected to the water flow protection device 13, and the flow detector 14 is installed on the water flow protection device 13, and the flow detector 14 is located on one side of the sample stage 1; the fourth lens 6-4, the laser flow measurement device 11, the water flow protection device 13 and the flow detector 14 together constitute a laser flow measurement module for monitoring and adjusting the water flow state; the second beam of light enters the laser density measurement device 12 through the fifth lens 6-5, and the front end of the laser density measurement device 12 is connected to the laser density measurement detector 8; the fifth lens 6-5. The laser density measurement device 12 and the laser density measurement detector 8 together constitute a laser density measurement module, which is used for non-contact measurement of the density ρ of the bone to be cut and the laser absorption rate α; the third beam of light enters the laser ranging device 16, the front end of the laser ranging device 16 is connected to the laser ranging detector 17, and the laser ranging detector 17 is tightly integrated with the cutting laser head 18. The laser ranging device 16 and the laser ranging detector 17 together constitute a laser ranging module, which is used to measure the distance between the cutting laser head 18 and the cutting surface of the bone to be cut; the fourth beam of light serves as the main cutting beam, and after being scanned and focused by the first reflective galvanometer 7-1 and the second lens 6-2, it directly acts on the bone to be cut through the cutting laser head 18.

[0060] The ultraviolet laser emitted by the ultraviolet laser 3 is divided into two beams of light by the first beam splitter 4-1. The first beam of light passes through the laser-induced breakdown energy spectrum device 9, which is used to excite and analyze the bone plasma spectrum in real time during the cutting process, mainly monitoring the changes in the content of elements such as nitrogen (N); the second beam of light serves as an auxiliary cutting beam, which is scanned and focused by the first lens 6-1, the second reflective galvanometer 7-2 and the third lens 6-3, and then acts directly on the bone to be cut through the cutting laser head 18.

[0061] The temperature detector 10 is installed on the side of the sample stage 1 and is directly aimed at the cutting area for real-time monitoring of the cutting point temperature.

[0062] The ultrasonic thickness gauge 15 is installed on the side of the sample stage 1 and is used to measure the thickness of different positions of the cut bone.

[0063] The indicating light source 5 is used to indicate the laser cutting position and assist in positioning.

[0064] The computer controller 19 includes a central processing unit and a memory. All detectors and lasers are connected to the computer controller 19 for data acquisition, processing and closed-loop control.

[0065] All components except the computer controller 19 are placed in a protective cover 20, which is provided with a sound insulation layer to significantly reduce operating noise.

[0066] In the composite laser cutting module, the infrared laser 2 is a Nd:YAG laser with a wavelength of 1064nm and an output power range of 5-50W; the ultraviolet laser 3 is a solid-state laser with a wavelength of 355nm and an output power range of 1-10W.

[0067] The highly efficient intelligent feedback bone cutting method based on multi-laser monitoring is as follows: Figure 2 As shown, the following steps are included:

[0068] Step 1: Place the bone to be cut on the sample stage 1 according to its characteristics, calibrate the direction, and ensure that the normal direction of the surface of the bone to be cut is consistent with the main optical axis direction of the cutting laser head 18.

[0069] Step 2: Under the control of computer controller 19, ultrasonic thickness gauge 15 is moved to the initial cutting position. The thickness H of the bone to be cut is measured point by point along the planned cutting path at a sampling interval of 1-10 mm. The measured thickness data is recorded and stored in the memory of computer controller 19.

[0070] Step 3: Based on the thickness data, the positions where the thickness change rate ΔH is greater than a preset threshold (e.g., 3%) are segmented and the segmentation information (starting point, end point, average thickness, etc. of each segment) is recorded in the memory of the computer controller 19; the thickness change rate ΔH is calculated using the following formula:

[0071]

[0072] Among them, H max is the maximum thickness, H min is the minimum thickness, H avg is the average thickness.

[0073] Step 4: The computer controller 19 turns on the infrared laser 2 and controls the laser density measurement module to output a low-power infrared laser. The laser density measurement detector 8 obtains the bone density ρ and laser absorption rate α of the current region through non-contact measurement. The computer controller 19 calculates the power P of the infrared main cutting laser for the segment based on the measured bone density ρ and laser absorption rate α of the current region, combined with the average thickness information of the current segment:

[0074] P=k·ρ·α

[0075] Wherein, k is the power coefficient, which is determined by experimental data and obtained through preliminary experimental calibration, and is related to factors such as laser wavelength, spot size, and desired cutting speed; ρ is the bone density in the current area; and α is the laser absorptivity.

[0076] Step 5. Move the cutting laser head 18 to the starting section of the first segment, start the laser ranging module, measure the distance d between the cutting laser head 18 and the cutting surface, and adjust the height of the cutting laser head 18 according to the ranging result to ensure that the working distance is stable within the preset optimal focal depth range (for example, d = 2.0 ± 0.1 mm).

[0077] Step 6: After confirming that the cutting laser head height meets the requirements, output high-power infrared laser for cutting, and at the same time start the temperature detector 10 to monitor the cutting point temperature in real time.

[0078] Step 7: Based on the bone density ρ and laser absorption rate α data of the current area obtained in step 4, as well as the thickness data of the current segment, the computer controller 19 calculates and sets the initial laser parameters (power P, scanning speed, frequency), and the computer controller 19 drives the infrared main cutting beam to scan and cut according to the preset path.

[0079] Step 8: During the cutting process, the water flow protection device 13 is activated to supply cooling water to the cutting area. The water flow rate Q0 is proportional to the current infrared laser power. Simultaneously, the laser flow measurement module is activated to monitor and adjust the water flow at different locations. The computer controller 19 fine-tunes the output of the water flow protection device 13 based on flow feedback to ensure stable cooling.

[0080] Step 9: Monitor the data of the temperature detector 10 in real time. To prevent carbonization of the cut surface due to excessive temperature, when the temperature approaches the safety threshold (45°C), reduce the laser power density P and increase the water flow appropriately to reduce the temperature. The water flow adjustment formula is:

[0081] Q new =Q0(1+β)

[0082] Among them, Q new is the adjusted water flow rate, Q0 is the current water flow rate, and β is the water flow adjustment coefficient, which is determined according to the temperature rise rate and amplitude, and the typical value range is 0.2 to 0.5.

[0083] If the temperature is lower than the efficiency threshold (40°C), the working efficiency will decrease and the power density needs to be increased. The power adjustment formula is:

[0084] P new =P0(1+γ)

[0085] Among them, P new is the adjusted laser power, P0 is the current laser power, and γ is the power adjustment coefficient, with a typical value range of 0.1 to 0.2.

[0086] Step 10: The computer controller 19 calculates the cutting depth h in real time using the thermal model based on the laser cutting parameters and the measured bone thickness:

[0087]

[0088] Where H is the total bone thickness; E is the laser energy density; t is the cutting time; and D is the thermal diffusivity.

[0089] When the cutting depth h reaches 95% of the total thickness H, the infrared laser 2 is turned off and the ultraviolet laser 3 is turned on. The water flow rate at this point is adjusted proportionally to the ultraviolet laser power. Simultaneously, the laser-induced breakdown spectroscopy device 9 is activated for real-time measurement. Real-time spectral analysis of the plasma generated in the cutting area is performed, with a focus on monitoring the intensity of the characteristic spectral line of nitrogen (N). When the intensity of the nitrogen characteristic spectral line exceeds five standard deviations from the baseline, the area is considered cut complete. The ultraviolet laser 3 and water flow protection device 13 are immediately turned off.

[0090] Step 11: The computer controller 19 controls the cutting laser head 18 to move to the starting section of the second segment, and repeats steps 4 to 10 until the cutting of the second segment is completed.

[0091] Step 12: After all segments are cut, all devices are turned off and the cut bone samples are removed from the sample stage 1.

[0092] Taking rib cutting as an example, the present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.

[0093] like Figure 2 , including the following steps:

[0094] 1) Place the rib sample to be inspected firmly on the sample stage 1, adjust the rib position so that the surface to be cut is as parallel to the laser scanning plane as possible (i.e., the normal direction of the cutting surface is basically consistent with the optical axis direction of the cutting laser head 18), and set the cutting contour path in the computer controller.

[0095] 2) The computer controller 19 controls the ultrasonic thickness gauge 15 to move along the set window path, measures the rib thickness at 5 mm intervals, and records the rib thickness data H into the memory.

[0096] 3) Based on the measured rib thickness data, the thickness change rate of each point on the path is automatically calculated. Positions where the thickness change rate ΔH is greater than 3% are segmented and recorded in the memory.

[0097] 4) The computer controller 19 turns on the infrared laser 2 and controls the laser density measurement module to measure at the starting point of segment 1 to obtain the bone density ρ and laser absorptivity α of the area. The initial cutting power of the infrared main cutting laser for this segment is calculated according to the formula (P = 35W);

[0098] 5) Move the cutting laser head 18 to the starting section of segment 1, start the laser distance measurement module, measure the current distance d = 2.5 mm between the cutting laser head 18 and the cutting surface, and adjust the height of the cutting laser head to d = 2.0 mm;

[0099] 6) Set the infrared laser power to 35 W. Simultaneously start the temperature detector 10 to monitor the cutting point temperature.

[0100] 7) The computer controller 19 drives the infrared main cutting beam to scan and cut segment one along the path, and dynamically adjusts the laser power through density data, thickness data, distance data, and temperature data in real time;

[0101] 8) Turn on the water flow protection device 13, and set the initial water flow rate according to 35W power. At the same time, turn on the laser flow measurement module to monitor and adjust the water flow state. The real-time temperature display is 42℃. To prevent carbonization, the computer controller 19 automatically reduces the laser power to 33W (P new =35(1-γ), γ≈0.057), and increase the water flow by 20% (Q new =Q0*1.2,β=0.2).

[0102] 9) When the calculated cutting depth of the current area has reached 95% of the total thickness (thickness 5mm, calculated depth 4.75mm), turn off the infrared laser 2 and start the ultraviolet laser 3. The water flow setting is proportional to the ultraviolet laser module.

[0103] 10) Start the laser-induced breakdown spectroscopy device 9. The intensity of the nitrogen characteristic line remains low, and the UV laser continues to refine the cut. After approximately 1 second, the intensity of the nitrogen characteristic line suddenly increases significantly (exceeding 5 standard deviations above the baseline), indicating that the cut is complete. Immediately shut down the UV laser 3 and the water flow protection device 13.

[0104] 11) Move the cutting laser head 18 to the starting point of segment 2. Repeat steps 4 (measure the density / absorption rate of segment 2 and calculate the new power P = 28W), step 5 (adjust the distance to 2.0mm), and steps 6-10 to complete the cutting of segment 2.

[0105] 14) After all segments have been cut, all equipment is turned off and the ribs are removed to obtain bones with neat edges, no carbonization, and no damage to the underlying tissue.

[0106] The rib bones after cutting in this example are as follows Figure 3 As shown, from Figure 3 It can be seen that the cutting edge is highly smooth, without the bone cracks or burrs common in traditional mechanical cutting; the cutting surface is smooth and free of carbonization, effectively preventing thermal damage; the incision width is uniform and consistent.

Claims

1. A high-efficiency intelligent feedback bone cutting device based on multi-laser monitoring, characterized by: include: The invention comprises a sample table (1) for fixing the bone to be cut, a composite laser cutting module for cutting the bone to be cut, a laser flow measurement module for monitoring and adjusting the water flow state, a laser density measurement module for non-contact measurement of the density of the bone to be cut and the laser absorption rate, and a laser distance measurement module for measuring the distance between the cutting laser head and the cutting surface; a temperature detector (10) installed on the side of the sample table (1) and directly aimed at the cutting area for real-time monitoring of the cutting point temperature; an ultrasonic thickness gauge (15) installed on the side of the sample table (1) for measuring the thickness of different positions of the cut bone; an indicating light source (5) for indicating the laser cutting position and assisting in positioning; and a computer controller (19) including a central processing unit and a memory for data acquisition, processing and closed-loop control.

2. The high-efficiency intelligent feedback bone cutting device based on multi-laser monitoring according to claim 1, characterized in that: The composite laser cutting module comprises an infrared laser (2), an ultraviolet laser (3), a first beam splitter (4-1), a second beam splitter (4-2), a first lens (6-1), a second lens (6-2), a third lens (6-3), a first reflection galvanometer (7-1), a second reflection galvanometer (7-2), and a cutting laser head (18); The infrared laser emitted by the infrared laser (2) is divided into four beams through the second beam splitter (4-2): the first beam passes through the fourth lens (6-4) and enters the laser flow measurement device (11), the front end of the laser flow measurement device (11) is connected to the water flow protection device (13), the water flow protection device (13) is installed with a flow detector (14), and the flow detector (14) is located on one side of the sample stage (1); the fourth lens (6-4), the laser flow measurement device (11), the water flow protection device (13) and the flow detector (14) together constitute a laser flow measurement module; the second beam passes through the fifth lens (6-5) and enters the laser density measurement device ( 12), the front end of the laser density measuring device (12) is connected to the laser density measuring detector (8); the fifth lens (6-5), the laser density measuring device (12) and the laser density measuring detector (8) together constitute a laser density measuring module; the third beam of light enters the laser distance measuring device (16), the front end of the laser distance measuring device (16) is connected to the laser distance measuring detector (17), and the laser distance measuring device (16) and the laser distance measuring detector (17) together constitute a laser distance measuring module; the fourth beam of light serves as the main cutting beam, and after being scanned and focused by the first reflecting galvanometer (7-1) and the second lens (6-2), it directly acts on the bone to be cut through the cutting laser head (18); The ultraviolet laser light emitted by the ultraviolet laser (3) is divided into two beams by a first beam splitter (4-1). The first beam passes through a laser-induced breakdown energy spectrum device (9) and is used to excite and analyze the bone plasma spectrum in real time during the cutting process to monitor changes in nitrogen content. The second beam serves as an auxiliary cutting beam. After being scanned and focused by a first lens (6-1), a second reflective galvanometer (7-2) and a third lens (6-3), it is directly applied to the bone to be cut through a cutting laser head (18). All detectors and lasers are connected to a computer controller (19).

3. The high-efficiency intelligent feedback bone cutting device based on multi-laser monitoring according to claim 1, characterized in that: The other components except the computer controller (19) are placed in the protective cover (20), and a sound insulation layer is provided in the protective cover (20) to reduce working noise.

4. The high-efficiency intelligent feedback bone cutting device based on multi-laser monitoring according to claim 1, characterized in that: The infrared laser (2) is a Nd:YAG laser with a wavelength of 1064 nm and an output power range of 5-50 W.

5. The high-efficiency intelligent feedback bone cutting device based on multi-laser monitoring according to claim 1, characterized in that: The ultraviolet laser (3) is a fully solid-state laser with a wavelength of 355 nm and an output power range of 1-10 W.

6. The bone cutting method of claim 2, wherein: The steps include: Step 1: Place the bone to be cut on the sample table (1) according to the characteristics of the bone to be cut, calibrate the direction, and ensure that the normal direction of the surface of the bone to be cut is consistent with the main optical axis direction of the cutting laser head (18); Step 2: The ultrasonic thickness gauge (15) is moved to the initial cutting position under the control of the computer controller (19), and the thickness data H of the bone to be cut at the cutting position is measured point by point along the planned cutting path at a preset sampling interval using the ultrasonic thickness gauge (15), and the measured thickness data is recorded and stored in the memory of the computer controller (19); Step 3: Based on the thickness data H, the positions where the thickness change rate ΔH is greater than a preset threshold are segmented, and the segmentation information, i.e., the starting point, end point, and average thickness of each segment, is recorded in the memory of the computer controller (19); Step 4: The computer controller (19) turns on the infrared laser (2), controls the laser density measurement module to output low-power infrared laser, and the laser density measurement detector (8) obtains the bone density ρ and laser absorption rate α data of the current region through non-contact measurement; the computer controller (19) calculates the power P of the infrared main cutting laser of the segment based on the measured bone density ρ and laser absorption rate α of the current region, combined with the average thickness information of the current segment: P=k·ρ·α Where k is the power coefficient; ρ is the bone density of the current area; α is the laser absorption rate; Step 5: Move the cutting laser head (18) to the starting section of the first segment, start the laser distance measurement module, measure the distance d between the cutting laser head (18) and the cutting surface, and adjust the height of the cutting laser head (18) according to the distance measurement result to ensure that the working distance is stable within the preset optimal focal depth range; Step 6: After confirming that the cutting laser head height meets the requirements, output high-power infrared laser for cutting, and simultaneously start the temperature detector (10) to monitor the cutting point temperature in real time; Step 7: Based on the bone density ρ and laser absorption rate α data of the current region obtained in step 4, and the thickness data of the current segment, the computer controller (19) calculates and sets the initial laser parameters, and the computer controller (19) drives the infrared main cutting beam to scan and cut along a preset path; Step 8: During the cutting process, the water flow protection device (13) is turned on to provide cooling water to the cutting area; the water flow rate is proportional to the current infrared laser power; at the same time, the laser flow measurement module is turned on to monitor and adjust the water flow status at different positions, and the computer controller (19) fine-tunes the output of the water flow protection device (13) based on the flow feedback to ensure a stable cooling effect; Step 9: Real-time monitoring of the data of the temperature detector (10). To prevent carbonization of the cutting surface due to excessive temperature, when the temperature approaches the temperature safety threshold, the laser power density P is reduced and the water flow rate is increased to cool down. The water flow adjustment formula is: Q new =Q0(1+β) Among them, Q new is the adjusted water flow rate, Q0 is the current water flow rate, and β is the water flow adjustment coefficient, which is determined according to the temperature rise rate and amplitude; If the temperature is lower than the temperature efficiency threshold, the working efficiency will decrease and the power density needs to be increased. The power adjustment formula is: P new =P0(1+γ) Among them, P new is the laser power after adjustment, P0 is the current laser power, and γ is the power adjustment coefficient; Step 10: The computer controller (19) calculates the cutting depth h in real time using the thermal model according to the laser cutting parameters and the measured bone thickness: Where H is the total bone thickness; E is the laser energy density; t is the cutting time; D is the thermal diffusivity; When the cutting depth h reaches 95% of the total thickness H, the infrared laser (2) is turned off and the ultraviolet laser (3) is turned on; the water flow rate at this time is adjusted to be proportional to the ultraviolet laser power; at the same time, the laser induced breakdown energy spectrum device (9) is started to perform real-time measurement, and the plasma generated in the cutting area is subjected to real-time spectrum analysis, with a focus on monitoring the intensity of the characteristic spectrum line of the nitrogen element. When the intensity of the characteristic spectrum line of the nitrogen element exceeds 5 times the standard deviation of the baseline, it is determined that the cutting of the area is completed, and the ultraviolet laser (3) and the water flow protection device (13) are immediately turned off; Step 11: The computer controller (19) controls the cutting laser head (18) to move to the starting section of the second segment, and repeats steps 4 to 10 until the cutting of the second segment is completed; Step 12: After all the segments are cut, all devices are turned off and the cut bone samples are removed from the sample table (1).

7. The bone cutting method according to claim 6, wherein: The sampling interval is 1-10 mm.

8. The bone cutting method according to claim 6, wherein: The temperature safety threshold is 45°C.

9. The bone cutting method according to claim 6, wherein: The temperature efficiency threshold is 40°C.

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