Postoperative pain relief device for children

Abstract

This invention discloses a postoperative fixation and pain relief device for children, relating to the field of medical orthopedic external fixation technology. The device includes a limiting shell that can be simultaneously fitted onto the patient's forearm and upper arm. Multiple airbags are fixedly connected to the inner side of the limiting shell, categorized as distal and proximal airbags based on their distance from the patient's heart. A miniature air pump is fixedly connected to the limiting shell, with its outlet connected to the proximal airbag. The multiple airbags are connected via capillary tubes, allowing for sequential inflation from distal to proximal. Each airbag is equipped with a pressure relief valve to limit the internal working pressure. The miniature air pump operates intermittently. This device achieves stable immobilization of the affected limb through a rigid limiting shell and utilizes capillary flow resistance to achieve purely mechanical sequential centripetal pressure, simultaneously reducing swelling and pain, promoting healing, and preventing complications. Its simple and reliable structure is suitable for the fixation and rehabilitation needs after upper limb fracture surgery in children.

Description

Technical Field

[0001] This invention relates to the field of medical orthopedic external fixation technology, and in particular to a postoperative fixation and pain relief device for children. Background Technology

[0002] Upper limb fractures in children are among the most common types of trauma in pediatric orthopedic clinics. Effective external fixation after surgery is the core foundation for maintaining the alignment and stability of the fracture ends and ensuring normal callus growth. Current clinical protocols mostly use rigid plaster casts or custom-made braces as a limiting shell to simultaneously wrap and immobilize the forearm and upper arm of the affected limb. By restricting bending and twisting movements of the affected limb, angulation and displacement of the fracture ends are avoided, providing a stable biomechanical environment for postoperative healing.

[0003] However, traditional external fixation devices only provide a single rigid immobilization function. The affected limb remains under static pressure for extended periods, obstructing venous and lymphatic return and causing continuous fluid accumulation in the interstitial spaces. This easily leads to swelling, persistent pain, and other discomfort in the affected limb. Children have lower pain tolerance, and postoperative swelling and pain can easily cause them to cry, resist wearing the device, and even remove it themselves. Furthermore, prolonged static fixation can lead to complications such as muscle disuse atrophy, joint capsule adhesions, and soft tissue contractures, significantly prolonging the postoperative recovery period.

[0004] To address postoperative swelling and pain, some improved fixation devices have added airbag structures. However, most existing airbags use a synchronous inflation and deflation mode, which cannot achieve progressive centripetal pressure from the distal to the proximal end of the limb. This does not conform to the physiological logic of manual lymphatic drainage, and the effect of reducing swelling and relieving pain is very limited.

[0005] In summary, existing postoperative arm fixation devices for children cannot achieve sequential compression therapy that conforms to the physiological return flow pattern through mechanical structure while ensuring rigid immobilization. They are unable to simultaneously meet the multiple clinical needs of fracture end stabilization, postoperative swelling and pain relief, and complication prevention, and have significant technical shortcomings. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention has developed a postoperative fixation and pain relief device for children. This device has the advantage of using a mechanical structure to achieve sequential pressure therapy that conforms to the physiological return flow pattern.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A postoperative pain relief device for children includes a limiting shell that is fitted onto both the forearm and upper arm of the patient. Multiple airbags are fixedly connected to the inner side of the limiting shell, including distal and proximal airbags positioned within the limiting shell according to their distance from the heart. A miniature air pump is fixedly connected to the limiting shell, with its outlet connected to the distal airbag. The multiple airbags are interconnected via capillary tubes, and are inflated sequentially from distal to proximal to the heart. Each airbag is equipped with a pressure relief valve to limit the working pressure within the airbag cavity. The miniature air pump operates intermittently.

[0009] Preferably, a cover sleeve is detachably connected inside the limiting shell. The cover sleeve is made of flexible material and is located between the airbag and the limiting shell. The airbag and the cover sleeve are fixedly connected.

[0010] Preferably, a magnetic sheet is fixedly connected to the outer end of the covering sleeve, and an adsorption sheet is fixedly connected to the inner end of the limiting shell to the magnetic sheet, with the magnetic sheet and the adsorption sheet being magnetically connected.

[0011] Preferably, the covering sheath has stress grooves for the magnetic sheet and capillary, and the stress grooves penetrate the covering sheath along the central axis of the covering sheath.

[0012] Preferably, the limiting shell has a through-hole for receiving groove, a floating plate is embedded in the receiving groove, the micro air pump is fixedly connected to the floating plate, and the receiving groove corresponds to the position of the patient's wound, and the floating plate is fixedly connected to the covering skin.

[0013] Preferably, two elastic rings are fixedly connected to the inner side of the covering sheath, the two elastic rings are located on both sides of the floating plate, and the inner end of the elastic rings abuts against the patient's skin.

[0014] Preferably, the pressure relief valve includes a valve body whose inner cavity communicates with the corresponding airbag. A limiting ring is fixedly connected in the inner cavity of the valve body, which divides the inner cavity of the valve body into a pressure-coordinated zone near the airbag and a pressure relief zone away from the airbag. A valve stem is axially slidably connected in the pressure relief zone, and an elastic element is provided between the valve stem and the inner wall of the valve body. When the air pressure in the pressure-coordinated zone is less than a threshold, the elastic element releases elastic potential energy to push the valve stem against the limiting ring and block the central hole of the limiting ring. When the air pressure in the pressure-coordinated zone is greater than the threshold, the valve stem moves in the direction away from the limiting ring, and at this time the pressure-coordinated zone and the pressure relief zone are connected.

[0015] Preferably, the inner wall of the valve body is elastically connected with protrusions, and multiple sets of protrusions are arranged along the central axis of the valve body, and the valve stem is provided with an embedding groove for the protrusions.

[0016] Preferably, the number of proximal airbags is not less than two, and at least one proximal airbag is fitted onto the patient's upper arm.

[0017] Preferably, each airbag is connected to a safety valve, which is used to limit the maximum air pressure inside the airbag cavity.

[0018] Compared with the prior art, the beneficial effects of the present invention are:

[0019] This invention achieves rigid immobilization of the entire affected limb through a limiting shell that simultaneously covers both the patient's forearm and upper arm, effectively limiting limb twisting and bending, preventing displacement of fracture ends, and providing a stable mechanical basis for postoperative healing. By arranging distal and proximal airbags on the inner side of the limiting shell according to their distance from the heart, and utilizing the flow resistance characteristics of the capillary tubes of the airbags connected in series, multiple airbags can be sequentially inflated from distal to proximal using a purely mechanical structure, forming a continuous wave-like centripetal compression effect. This precisely replicates the working logic of manual lymphatic drainage, accelerating the return of blood and lymph fluid to the affected limb, rapidly reducing interstitial pressure, and alleviating pressure on subcutaneous nerve endings, thus relieving postoperative swelling and pain from the root cause. At the same time, the orderly pressure stimulation can activate skin tactile receptors, competitively blocking the transmission of pain signals to the spinal cord, further enhancing the pain relief effect. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0021] Figure 2 This is a schematic diagram showing the positional relationship between the floating plate and the micro air pump of the present invention;

[0022] Figure 3 This is a schematic diagram showing the connection relationship between the limiting shell and the adsorption sheet of the present invention;

[0023] Figure 4 This is a schematic diagram showing the connection between the leather sheath and the magnetic sheet of the present invention;

[0024] Figure 5 This is a schematic diagram showing the relationship between the capillary tube and the air bladder in this invention;

[0025] Figure 6 This is a schematic diagram showing the positional relationship between the sheath and the elastic ring of the present invention;

[0026] Figure 7 This is a schematic diagram of the overall structure of the pressure relief valve of the present invention;

[0027] Figure 8 This is a schematic diagram of the overall structure of the safety valve of the present invention.

[0028] In the diagram: 1. Limiting housing; 2. Pressure relief valve; 21. Valve body; 22. Limiting ring; 23. Valve stem; 24. Protrusion; 25. Embedded groove; 3. Safety valve; 4. Covering sleeve; 5. Airbag; 51. Distal airbag; 52. Proximal airbag; 6. Miniature air pump; 7. Stress groove; 8. Adsorption plate; 9. Capillary tube; 10. Magnetic plate; 11. Floating plate; 12. Elastic ring. Detailed Implementation

[0029] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0031] Please refer to Figure 1-8 The postoperative fixation and pain relief device for children is mainly used for postoperative external fixation and pain intervention for arm fractures (including common types such as distal radius fracture, radius and ulna fracture, and supracondylar fracture of the humerus) in children aged 3 to 12 years. It can also be used as an adjunct treatment for soft tissue injuries of the upper limbs and during the postoperative rehabilitation period in children.

[0032] This device adopts a split architecture consisting of a "customized rigid limiting shell 1 + universal modular pneumatic functional layer". On the one hand, the anatomically fitted rigid shell achieves stable immobilization of the fracture ends, preventing torsion and angular displacement. On the other hand, through pure mechanical sequential pneumatic pressurization and air pump vibration reuse technology, it synergistically achieves multiple clinical effects such as reducing swelling, relieving pain, preventing complications, and promoting bone healing. While ensuring fixation strength, it significantly improves wearing comfort and usage safety, and at the same time significantly reduces the overall cost of customized use.

[0033] Please refer to Figure 1 Consistent with existing technology devices, it mainly includes a limiting shell 1 that is fitted onto the patient's arm. The limiting shell 1 is custom-made from a rigid plastic material that has a certain elastic deformation capability and meets medical safety standards.

[0034] In actual manufacturing, the limiting shell 1 has a notch or groove extending along the length of the patient's arm. Medical personnel can use this notch or groove to open the limiting shell 1 and place it on the patient's arm. The limiting shell 1 is simultaneously placed on both the patient's forearm and upper arm. Utilizing the strong wrapping effect of the customized limiting shell 1, it effectively restricts the patient's arm, preventing it from twisting or bending freely during postoperative recovery. This avoids complications such as wound dehiscence and fracture displacement caused by improper activity.

[0035] In practice, medical-grade copolymer polypropylene (PP-R) is preferred due to its excellent fatigue resistance, biocompatibility, and moderate elastic deformation capacity. Meanwhile, the limiting shell 1 can be manufactured using semi-custom thermoplastic molding or fully custom 3D printing.

[0036] Please refer to Figure 1-6 Unlike existing technology devices, this device has multiple airbags 5 fixedly connected inside the limiting housing 1, and the multiple airbags 5 are arranged at intervals along the axial direction of the limiting housing 1.

[0037] In the technical solution of this invention, the multiple airbags 5 specifically include a distal airbag 51 and a proximal airbag 52. The distal airbag 51 and the proximal airbag 52 are arranged sequentially within the limiting shell 1 according to their distance from the patient's heart. The distal airbag 51 is located further away from the patient's heart, and the proximal airbag 52 is located closer to the patient's heart. This spatial arrangement enables orderly pressure application from the distal to the proximal end of the limb, laying a structural foundation for achieving a sequential lymphatic drainage effect.

[0038] In actual operation, airbag 5 inflates sequentially from the distal end (wrist) to the proximal end (elbow and upper arm), creating a continuous "wave-like compression" effect. The distal airbag 5 is pressurized first, pushing the blood and lymph fluid accumulated at the extremities towards the proximal end; subsequently, the proximal airbags 5 are pressurized sequentially, continuously propelling the fluid towards the heart, perfectly replicating the centripetal pressure logic of manual lymphatic drainage. This sequential compression method can rapidly reduce interstitial pressure by accelerating tissue fluid return, alleviating pressure on subcutaneous nerve endings and fundamentally relieving postoperative swelling and pain. Furthermore, the orderly pressure stimulation activates tactile receptors in the skin, competitively blocking pain signals from being transmitted to the spinal cord, achieving pain relief through gate control theory. Periodic soft tissue compression passively activates muscles, fascia, and joint capsules, maintaining tissue elasticity and reducing muscle atrophy, joint stiffness, and adhesions caused by prolonged immobilization, laying a good foundation for subsequent rehabilitation training. Regular sequential compression can also improve microcirculation around the fracture site, increase blood oxygen and nutrient perfusion, promote callus growth, and shorten the fracture healing period; at the same time, it can accelerate the excretion of inflammatory mediators and metabolic waste, and reduce chronic inflammatory response.

[0039] In some embodiments, the number of proximal airbags 52 is not less than two, and at least one proximal airbag 52 is fitted on the patient's upper arm. This arrangement can effectively extend the return distance of tissue fluid in the patient's arm and improve the lymphatic drainage effect.

[0040] Preferably, there are three proximal airbags 52. One of them is placed on the proximal end of the patient's forearm, near the elbow (corresponding to the area from the proximal end of the fracture line to 2cm below the elbow joint). The other two are placed on the patient's upper arm. The proximal airbags 52 placed on the patient's upper arm are located on the upper and lower sides of the biceps brachii muscle (corresponding to the area from 3cm above the elbow joint to the lower edge of the biceps brachii muscle, and the area from the upper edge of the biceps brachii muscle to 5cm below the armpit). This arrangement can avoid excessive pressure on the patient's biceps brachii muscle, while ensuring full coverage of the upper arm area.

[0041] Correspondingly, a miniature air pump 6 is fixedly connected to the limiting housing 1. The miniature air pump 6 is a medical-grade low-noise miniature air pump to ensure safety and comfort during use.

[0042] The outlet of the miniature air pump 6 is directly connected to the distal airbag 51 through an air guide tube, and multiple airbags 5 are interconnected through capillary tubes 9.

[0043] In practice, due to the small inner diameter of the capillary tube 9, according to Poiseuille's law, the flow resistance of gas inside a circular tube is directly proportional to the tube length and inversely proportional to the fourth power of the tube diameter. Therefore, the gas will encounter severe flow resistance when moving within its inner cavity. When the air pressure inside the distal air bladder 51 increases, the air pressure inside the proximal air bladder 52 can only increase slowly through the capillary tube 9. Utilizing this hydrodynamic characteristic, this invention can achieve the technical effect of sequentially inflating multiple air bladders 5 according to their distance from the heart, from farthest to near.

[0044] Preferably, the limiting housing 1 integrates a Bluetooth communication module, which connects to a smartphone APP to enable remote monitoring of the device's operating status and parameter adjustment. A battery can also be added to power the miniature air pump 6.

[0045] Each airbag 5 is connected to a pressure relief valve 2, which is used to limit the working air pressure inside the airbag 5, ensuring that the pressure inside the airbag 5 is always maintained within a safe and effective range, and avoiding discomfort or damage to the patient due to excessive pressure.

[0046] Correspondingly, the miniature air pump 6 adopts an intermittent working mode. In one working cycle, the miniature air pump 6 first works for a period of time to inflate the airbag 5. After reaching the preset pressure, it stops working. After the pressure inside the airbag 5 is reduced to the set lower limit through the pressure relief valve 2, the miniature air pump 6 starts inflating again. This cycle repeats to achieve a periodic pressure massage effect.

[0047] Please refer to Figure 2 , Figure 3 , Figure 4 Furthermore, a cover 4 is detachably connected inside the limiting shell 1. The cover 4 is made of medical-grade flexible material, such as silicone, medical PU leather or breathable non-woven fabric, to ensure comfort and biocompatibility in contact with the skin.

[0048] The covering sleeve 4 is located between the airbag 5 and the limiting shell 1, and the airbag 5 and the covering sleeve 4 are fixedly connected by medical adhesive or heat sealing process.

[0049] In practice, the presence of the protective sleeve 4 significantly improves the patient's experience. Since the limiting shell 1 is generally made of hard plastic, direct contact with a child's delicate skin can easily cause pressure sores or discomfort. The protective sleeve 4, acting as an intermediate cushioning layer, effectively disperses pressure and enhances wearing comfort. Furthermore, the fixed connection between the protective sleeve 4 and the airbag 5, as well as the detachable connection between the protective sleeve 4 and the limiting shell 1, allows both the protective sleeve 4 and the airbag 5 to be disinfected and reused. The flexible material of the protective sleeve 4 allows it to adapt to the arms of patients of different body types. In practical applications, only the limiting shell 1 needs to be customized to meet the needs of different patients. This significantly reduces medical costs and improves the economic efficiency and versatility of the device.

[0050] Please refer to Figure 3 , Figure 4 Specifically, a magnetic piece 10 is fixedly connected to the outer end of the cover 4. The magnetic piece 10 is made of neodymium iron boron permanent magnet material and is covered with a medical-grade plastic coating to ensure safety during use.

[0051] An adsorption piece 8, made of ferromagnetic material, is fixedly connected to the inner side of the limiting housing 1 at the position of the magnetic piece 10. The magnetic piece 10 and the adsorption piece 8 are magnetically connected by magnetic force. This connection method can greatly reduce the installation difficulty of the covering sleeve 4. Medical staff only need to roughly align the covering sleeve 4 to the position, and it can be automatically adsorbed and positioned by magnetic force.

[0052] In a preferred embodiment, a corresponding mounting groove is provided on the inner side of the limiting housing 1 for the position of the adsorption sheet 8. The adsorption sheet 8 is embedded in the mounting groove and fixed by ultrasonic welding or adhesive. At this time, by utilizing the strong frictional resistance between the covering leather sleeve 4 and the patient's arm and the fixed connection between the magnetic sheet 10 and the covering leather sleeve 4, the displacement of the covering leather sleeve 4 relative to the limiting housing 1 can be effectively prevented, ensuring that the limiting housing 1 has a stable and reliable limiting effect on the patient's arm.

[0053] Please refer to Figure 2 , Figure 4 , Figure 6The cover 4 also has stress grooves 7 for the positions of the magnetic sheet 10 and the capillary tube 9. The stress grooves 7 penetrate the cover 4 along the central axis of the cover 4.

[0054] The design of the stress groove 7 has multiple technical benefits: First, the covering sleeve 4 at the location of the stress groove 7 is relatively thin, which can avoid the high hardness of the magnetic sheet 10 and the capillary tube 9 causing local pressure discomfort to the patient (the magnetic sheet 10 is a hard magnetic material and the capillary tube 9 is a hard plastic. If they come into direct contact with the skin, they are prone to forming local high pressure points, which may cause pressure sores).

[0055] Secondly, the thinner and less rigid sheath at stress groove 7 is a key deformation area of ​​the sheath 4. When the arm swells or there are size discrepancies, stress groove 7 preferentially undergoes tensile or compressive deformation to absorb dimensional deviations and ensure uniform and stable pressure in other areas. By adjusting the density, depth, and distribution of stress groove 7, the compression intensity in different areas can be precisely controlled: in areas corresponding to fracture ends, stress groove 7 is sparsely distributed, and the sheath is more rigid, providing stronger fixation pressure; in areas corresponding to the medial nerve and blood vessel pathways and areas with abundant muscle, stress groove 7 is densely distributed, and the sheath is less rigid, providing gentler pressure and avoiding compression of nerves and blood vessels. This zoned gradient pressure design maximizes wearing safety and comfort while ensuring fixation strength, achieving the effect of "sufficiently firm fixation areas and sufficiently soft buffer zones."

[0056] Please refer to Figure 2 In some embodiments, a receiving groove is provided through the limiting housing 1, the position of the receiving groove corresponds to the position of the patient's wound, and a floating plate 11 is embedded in the receiving groove.

[0057] In practice, the floating plate 11 is made of lightweight medical plastic and can float slightly within the receiving groove. Therefore, this device restricts the connection between the miniature air pump 6 and the floating plate 11 to screws or clips, and the floating plate 11 is fixedly connected to the covering sleeve 4. Utilizing the floating characteristics of the floating plate 11, the minute vibrations generated during the operation of the miniature air pump 6 can be transmitted to the skin near the patient's wound (when the miniature diaphragm air pump is working, the motor drives the diaphragm to reciprocate, generating low-frequency vibrations of approximately 65Hz), thereby using vibration to achieve the purpose of massage and pain relief, as well as pain relief through attention diversion (pain gate control theory: when tactile receptors (Aβ fibers) are stimulated by vibration, glial cells are activated, inhibiting synaptic transmission of C fibers that transmit pain signals, thereby reducing the transmission of pain signals to the brain).

[0058] In addition, the high-frequency micro-vibrations generated by the micro air pump 6 during operation are transmitted to the tissues around the wound through the floating plate 11, which can promote local blood circulation and accelerate the reduction of swelling and pain.

[0059] Please refer to Figure 6 Furthermore, the device has two elastic rings 12 fixedly connected inside the covering skin 4. The two elastic rings 12 are located on both sides of the floating plate 11 (the two elastic rings 12 are located at the proximal and distal ends of the fracture end, respectively), and the inner end of the elastic ring 12 directly abuts against the patient's skin.

[0060] The elastic ring 12 is made of medical-grade silicone, possessing excellent elasticity and biocompatibility. Utilizing the direct contact between the elastic ring 12 and the patient's arm, the vibrations generated by the miniature air pump 6 during operation are effectively transmitted to the skin near the wound, further enhancing the pain-relieving effect of the vibration massage. The elasticity of the elastic ring 12 also acts as a buffer, preventing pulling or pressure on the skin around the wound. Furthermore, the two elastic rings 12, positioned on either side of the wound, provide support and fixation to the surrounding tissues, reducing traction and stimulation to the wound during arm movement.

[0061] Please refer to Figure 1 , Figure 7 Specifically, the pressure relief valve 2 includes a valve body 21, the inner cavity of the valve body 21 is connected to the inner cavity of the corresponding airbag 5, and a limiting ring 22 is fixedly connected in the inner cavity of the valve body 21. The limiting ring 22 divides the end of the valve body 21 close to the airbag 5 into a pressure zone and the end of the valve body 21 away from the airbag 5 into a pressure relief zone.

[0062] A valve stem 23 is axially slidably connected within the pressure relief zone, and an elastic element is provided between the valve stem 23 and the inner wall of the valve body 21. When the air pressure in the pressure zone is less than a set threshold, the elastic element releases its elastic potential energy, causing the valve stem 23 to abut against the limiting ring 22, blocking the central hole of the limiting ring 22. At this time, the pressure zone and the pressure relief zone are isolated from each other. When the air pressure in the pressure zone is greater than the set threshold, the thrust of the air pressure acting on the end face of the valve stem 23 overcomes the elastic force of the elastic element, pushing the valve stem 23 to move away from the limiting ring 22. At this time, the pressure zone and the pressure relief zone are connected, and excess gas in the airbag 5 can be discharged to the outside through the pressure relief zone.

[0063] In this embodiment, by utilizing the frictional resistance between the valve stem 23 and the valve body 21, when the amount of gas input to the airbag 5 is less than the amount of gas discharged by the pressure relief valve 2, the pressure relief valve 2 can have a certain delay in operation. Specifically, the valve stem 23 must transition from a state where the pressure applied to the valve stem 23 within the same pressure zone is greater than the sum of the resistance applied to the valve stem 23 by the elastic element and the frictional resistance between the valve body 21 and the valve stem 23, to a state where the sum of the pressure applied to the valve stem 23 within the same pressure zone and the frictional resistance between the valve body 21 and the valve stem 23 is less than the resistance applied to the valve stem 23 by the elastic element before the valve stem 23 can complete its reset action. This design also limits the operating condition where the amount of gas input to the airbag 5 is equal to or slightly greater than the amount of gas discharged by the pressure relief valve 2, allowing multiple airbags 5 to overcome the resistance of the capillary tube 9 and achieve gas flow, thus ensuring the stability of sequential inflation.

[0064] Furthermore, the device has a protrusion 24 elastically connected to the inner wall of the valve body 21. The protrusion 24 is made of rubber or silicone material and is connected to the inner wall of the valve body 21 through an elastic support arm.

[0065] Multiple sets of protrusions 24 are arranged along the central axis of the valve body 21, and the valve stem 23 has an embedding groove 25 corresponding to the position of the protrusion 24. In actual operation, when the protrusion 24 enters the embedding groove 25, the frictional resistance exerted by the protrusion 24 on the valve stem 23 can hinder the axial movement of the valve stem 23, thereby realizing the multi-stage pressure regulation function of the pressure relief valve 2. Initially, valve stem 23 is inserted into the central hole of limiting ring 22, blocking the limiting ring 22. When the thrust of the air pressure in the same pressure zone applied to valve stem 23 is greater than the sum of the resistance applied to valve stem 23 by the elastic element and the frictional resistance between protrusion 24 and valve stem 23, the relatively lower protrusion 24 disengages from the insertion groove 25, and valve stem 23 moves upward. At this time, the air pressure in the corresponding airbag 5 reaches the working air pressure, and micro air pump 6 continues to pump gas into the distal airbag 51 until the preset working time of micro air pump 6 is reached. At this time, multiple airbags 5 reach the expected air pressure, and the valve stems 23 of multiple pressure relief valves 2 do not block the central hole of limiting ring 22. Multiple airbags 5 start to depressurize synchronously until the sum of the thrust of the air pressure in the same pressure zone applied to valve stem 23 and the frictional resistance between protrusion 24 and valve stem 23 is less than the resistance applied to valve stem 23 by the elastic element. Then, valve stem 23 is reset under the action of the elastic element. Through this structure in which multiple sets of protrusions 24 cooperate with the embedded grooves 25, the pressure relief valve 2 can be opened and closed in a stepped manner, making the pressurization and depressurization process of the airbag 5 smoother and avoiding discomfort to the patient caused by sudden pressure changes.

[0066] Please refer to Figure 1 , Figure 8 Each airbag 5 is also connected to a safety valve 3, which is used to limit the maximum air pressure inside the airbag 5. As a second safety protection mechanism in addition to the pressure relief valve 2, it prevents the pressure inside the airbag 5 from being too high and excessively compressing the patient's arm due to the failure of the pressure relief valve 2.

[0067] In a preferred embodiment, the safety valve 3 and the pressure relief valve 2 adopt a similar structural principle. The difference is that the valve body 21 of the safety valve 3 may not have a protrusion 24 structure, and the valve stem 23 of the safety valve 3 may not have a corresponding embedded groove 25. This simplified design can reduce production and R&D costs. The opening pressure of the safety valve 3 is set to be higher than that of the pressure relief valve 2. Under normal operating conditions, the safety valve 3 remains closed. Only when the pressure relief valve 2 fails and causes the pressure inside the airbag 5 to continuously rise to a safety threshold will the safety valve 3 open to release pressure, ensuring patient safety.

[0068] Please refer to Figure 1-8 The actual working process of this device is as follows:

[0069] I. Preparation process for wearing and installing

[0070] Prefabricated limiting shell 1: Based on the 3D scan data of the child's affected limb, the braking main limiting shell 1 is manufactured using medical-grade polypropylene copolymer material through semi-custom thermoplastic molding or fully custom 3D printing. The shell has a through notch groove along the arm axis to ensure that it can expand and deform to fit the circumference of the affected limb when worn; at the same time, according to the location of the child's fracture wound, a receiving groove is prefabricated at the corresponding position of the shell for subsequent installation of the floating air pump assembly.

[0071] Wearing of the flexible functional layer on the affected limb: Take the pre-assembled covering leather sleeve 4 components - this component integrates all the airbags 5, capillary tubes 9 connected in series with each airbag 5, pressure relief valve 2 and safety valve 3 corresponding to each airbag 5, and two elastic rings 12 on the inner side of the floating plate 11 fixed at the corresponding position of the outer wound. Medical staff slip the protective sleeve 4 onto the wrist of the child's affected limb, pushing it upwards along the axial direction and adjusting its position: aligning the distal airbag 51 with the distal end of the wrist, and the proximal airbags 52 corresponding sequentially to the mid-forearm, proximal forearm, distal upper arm, and proximal upper arm, ensuring the airbags 5 are arranged along the limb axis in order of distance from the heart; finely adjusting the circumferential and axial positions so that the two elastic rings 12 on the inner side of the protective sleeve 4 fit against the proximal and distal ends of the wound skin, with the wound precisely located between the two rings; simultaneously, aligning the stress grooves 7 on the sleeve with the neurovascular pathways and bony prominences on the inner side of the affected limb, preventing hard components such as the magnetic sheet 10 and capillary tube 9 from directly contacting the skin and creating local high-pressure points.

[0072] Rigid limiting shell 1 is fastened and fixed: Medical staff use both hands to open the notch groove of limiting shell 1, and fasten the shell to the outside of the covering skin 4 from the outside of the affected limb. Adjust the axial and circumferential position of the shell so that the receiving groove on the shell is aligned with the floating plate 11 on the outside of the covering skin 4, so that the floating plate 11 is completely embedded in the receiving groove and can float slightly within the groove. During the alignment process, the adsorption plates 8 on the inside of the shell and the corresponding magnetic plates 10 on the outside of the covering skin 4 are automatically adsorbed and aligned by magnetic force.

[0073] Miniature air pump 6 installation: Install the miniature air pump 6 on the floating plate 11 and configure the required electric supply components.

[0074] II. Sequential inflation and pressurization process

[0075] Air pump startup and initial pressure gradient establishment: After receiving the start signal, the medical-grade low-noise miniature air pump 6 begins to work, inputting compressed gas into the tubing system of the airbag 5. Since all the airbags 5 are arranged in series through capillary tubes 9, the gas flow inside the tubes is hindered by extremely high flow resistance, resulting in a significant lag in air pressure transmission. Therefore, the air pressure rises fastest in the distal airbag 51, which is furthest from the air pump, and the air pressure rises more slowly in the airbags closer to the proximal end, naturally forming an initial pressure gradient that gradually decreases from the distal end of the limb to the proximal end.

[0076] The distal airbag 51 reaches and maintains pressure first: As the air pump continues to supply air, the internal air pressure of the distal airbag 51 first rises to the working threshold of the pressure relief valve 2.

[0077] After the pressure relief valve 2 is opened, the distal airbag 51 enters a constant pressure holding state: part of the gas continuously input by the air pump is discharged to the outside through the pressure relief zone of the pressure relief valve 2, so that the internal air pressure of the airbag 5 is stably maintained at the upper limit of the working pressure and will not continue to rise; the other part of the gas, driven by the stable pressure difference, flows into the proximal airbag 52 near the elbow of the forearm through the capillary tube 9 between the distal airbag 51 and the adjacent proximal airbag 52, pushing the air pressure of the airbag 5 to continue to rise.

[0078] By pre-matching the parameters of the inner diameter and length of the capillary tube 9 with the opening threshold of the pressure relief valve 2, it is possible to ensure that when the distal end airbag 51 just reaches the pressure relief threshold and enters the pressure holding state, the internal air pressure of the adjacent proximal end airbag 52 of the forearm is close to the working air pressure. Only a short period of continuous inflation is needed to reach the threshold, ensuring the continuity of the pressurization process and avoiding pressurization discontinuity.

[0079] The proximal airbag 5 gradually increases pressure: After the air pressure of the proximal airbag 52 near the elbow of the forearm rises to the working threshold of its own pressure relief valve 2, the above pressure holding logic is repeated: the pressure relief valve 2 opens to overflow, the air pressure of the airbag 5 is stabilized in the working pressure range, part of the excess gas is discharged to the outside, and part of it continues to be delivered to the distal airbag 5 of the upper arm, which is closer to the heart, through the rear capillary tube 9, pushing its air pressure to continue to rise to the threshold.

[0080] Following this pattern, airbag 5 reaches its working pressure and maintains pressure sequentially from the distal end of the wrist to the proximal end of the forearm, then to the distal end of the upper arm (below the biceps brachii), and finally to the proximal end of the upper arm (above the biceps brachii), creating a continuous wave-like squeezing effect that gradually advances from the distal to the proximal end of the limb. Each airbag 5 maintains stable pressure after reaching its pressure, continuously pushing blood and lymph fluid in that area further proximally, perfectly replicating the operational logic of manual lymphatic drainage: "pressurize distally first, then gradually advance proximally, and continuously push centripetally."

[0081] III. Collaborative Workflow of Pressure Holding and Stabilization with Vibration Pain Relief

[0082] When all airbags 5 reach the treatment working pressure and all pressure relief valves 2 enter the overflow pressure holding state, the device enters the full-section pressure holding stage. The pressure relief valves 2 maintain stable air pressure, and at the same time, the vibration of the micro air pump 6 is reused to achieve multiple pain relief effects.

[0083] Stepped pressure stabilization and maintenance: When the air pressure inside the airbag 5 is maintained within the working range, the elastic protrusion 24 on the upper part of the inner wall of the valve body 21 is engaged in the corresponding embedded groove 25 on the valve stem 23. The frictional force of the engagement prevents the valve stem 23 from moving up and down, so that the valve stem 23 is maintained at the corresponding opening. The air pressure in the airbag 5 remains stable within the set treatment range, achieving stepped pressure stabilization and avoiding frequent pressure fluctuations that may cause discomfort to the child.

[0084] Vibration-induced pain relief: During the entire process of air pump inflation and pressure holding, the approximately 65Hz low-frequency vibration generated by the micro diaphragm air pump is transmitted to the covering sheath 4 through the floating plate 11 fixedly connected to the air pump. The floating plate 11 is embedded in the receiving groove of the shell and can move slightly, reducing the vibration absorbed and lost by the rigid shell. The vibration is then concentrated and transmitted to the skin around the wound through the elastic rings 12 on both sides of the wound.

[0085] This vibration activates tactile receptors in the skin, competitively blocking the transmission of pain signals to the spinal cord based on the pain gate control theory, thus directly reducing pain perception. It also promotes local microcirculation around the wound, accelerating the removal of inflammatory mediators and metabolic waste, and alleviating local inflammation. Simultaneously, the gentle vibration can distract the child, reducing their focus on postoperative pain. The flexible material of the elastic ring 12 further buffers the vibration amplitude, preventing traction and irritation to the delicate skin around the wound.

[0086] IV. Stepped pressure relief procedure

[0087] Once the miniature air pump 6 reaches the preset inflation time, it stops supplying air, and the device enters the depressurization phase. The air pressure gradually decreases to avoid discomfort in the affected limb. The specific process is as follows:

[0088] The air pressure gradually decreases: After the air pump stops supplying air, the airbag 5 system loses its external air source input. The gas in each airbag 5 continues to be discharged outward through the pressure relief zone of the pressure relief valve 2. The air pressure in the pressure zone gradually decreases, and the gas thrust on the valve stem 23 continuously decreases. When the sum of the gas thrust and the frictional force of the engagement of the protrusion 24 is less than the restoring elastic force of the elastic element, the protrusion 24 disengages from the current insertion groove 25, and the valve stem 23 falls back one level towards the limiting ring 22, corresponding to a decrease in the pressure relief opening and a slowdown in the pressure relief rate. As the air pressure continues to decrease, the protrusion 24 sequentially engages with the lower insertion grooves 25, and the valve stem 23 falls back step by step, achieving a step-by-step slow decrease in the air pressure of the airbag 5, avoiding discomfort such as soreness and numbness in the affected limb caused by a sudden drop in pressure.

[0089] Valve stem 23 reset and lock: When the air pressure in the airbag 5 drops back to the set lower limit value, the valve stem 23 is fully reset under the action of the elastic element, abuts against the limit ring 22 again and seals the central hole, the pressure zone and the pressure relief zone are completely isolated, and the pressure relief stops; at this time, the airbag 5 maintains a low base pressure and remains in contact with the skin of the affected limb, waiting for the next inflation cycle to start.

[0090] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A postoperative fixation and pain relief device for children, comprising a limiting shell (1) fitted onto the patient's arm, the limiting shell (1) being fitted onto both the patient's forearm and upper arm, characterized in that: Multiple airbags (5) are fixedly connected to the inner side of the limiting shell (1), and the multiple airbags (5) include a distal airbag (51) and a proximal airbag (52). The distal airbag (51) and the proximal airbag (52) are set in the limiting shell (1) according to their distance from the patient's heart. A miniature air pump (6) is fixedly connected to the limiting housing (1). The air outlet of the miniature air pump (6) is connected to the distal air bladder (51). Furthermore, the multiple air bladders (5) are connected to each other through capillary tubes (9), and the multiple air bladders (5) are inflated sequentially from far to near the heart. Each of the airbags (5) is connected to a pressure relief valve (2), which is used to limit the working air pressure inside the airbag (5), and the micro air pump (6) works intermittently.

2. The postoperative fixation and pain relief device for children according to claim 1, characterized in that: The limiting shell (1) is detachably connected to a covering leather sleeve (4). The covering leather sleeve (4) is made of flexible material and is located between the airbag (5) and the limiting shell (1). The airbag (5) is fixedly connected to the covering leather sleeve (4).

3. The postoperative fixation and pain relief device for children according to claim 2, characterized in that: A magnetic sheet (10) is fixedly connected to the outer end of the covering leather sleeve (4), and an adsorption sheet (8) is fixedly connected to the inner end of the limiting shell (1) in relation to the magnetic sheet (10). The magnetic sheet (10) and the adsorption sheet (8) are magnetically connected.

4. The postoperative fixation and pain relief device for children according to claim 3, characterized in that: The covering sheath (4) has stress grooves (7) for the magnetic sheet (10) and the capillary (9), and the stress grooves (7) penetrate the covering sheath (4) along the central axis direction.

5. The postoperative fixation and pain relief device for children according to claim 2, characterized in that: The limiting housing (1) has a through-hole for receiving groove, and a floating plate (11) is embedded in the receiving groove. The micro air pump (6) is fixedly connected to the floating plate (11). The receiving groove corresponds to the position of the patient's wound, and the floating plate (11) is fixedly connected to the covering skin (4).

6. The postoperative fixation and pain relief device for children according to claim 5, characterized in that: The inner side of the covering sleeve (4) is fixedly connected to two elastic rings (12), which are located on both sides of the floating plate (11), and the inner end of the elastic ring (12) is in contact with the patient's skin.

7. The postoperative fixation and pain relief device for children according to claim 1, characterized in that: The pressure relief valve (2) includes a valve body (21) whose inner cavity is connected to the corresponding airbag (5). A limiting ring (22) is fixedly connected in the inner cavity of the valve body (21). The limiting ring (22) divides the inner cavity of the valve body (21) into a pressure zone close to the airbag (5) and a pressure relief zone away from the airbag (5). A valve stem (23) is axially slidably connected within the pressure relief zone. An elastic element is provided between the valve stem (23) and the inner wall of the valve body (21). When the air pressure in the same pressure zone is less than the threshold, the elastic element releases elastic potential energy to push the valve stem (23) against the limiting ring (22) and block the central hole of the limiting ring (22). When the air pressure in the same pressure zone is greater than the threshold, the valve stem (23) moves away from the limiting ring (22), and at this time the same pressure zone and the pressure relief zone are connected.

8. The postoperative fixation and pain relief device for children according to claim 7, characterized in that: The valve body (21) has a protrusion (24) elastically connected to its inner wall. Multiple sets of protrusions (24) are arranged along the central axis of the valve body (21), and the valve stem (23) has an embedded groove (25) for the protrusions (24).

9. The postoperative fixation and pain relief device for children according to claim 1, characterized in that: The number of proximal airbags (52) is not less than two, and at least one proximal airbag (52) is fitted on the patient's upper arm.

10. The postoperative fixation and pain relief device for children according to claim 1, characterized in that: Each of the airbags (5) is connected to a safety valve (3), which is used to limit the maximum air pressure inside the airbag (5).

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