A natural orifice transluminal endoscopic tissue cryobiopsy needle

Abstract

The application relates to the technical field of cavity tissue biopsy needles, in particular to a natural cavity tissue cryobiopsy needle suitable for an ultrasonic endoscope. The technical scheme comprises an operation handle, a flexible outer sleeve, a gas supply pipeline, a flexible transmission shaft, a refrigeration unit and a tissue sampling head. The operation handle is internally provided with a gas source interface, a gas control valve and a micro motor, a carbon dioxide cylinder supplies gas to the refrigeration unit through the gas source interface and the gas supply pipeline, the refrigeration unit utilizes the Joule-Thomson effect to reduce the temperature of the contact surface to minus twenty to forty degrees Celsius, the target tissue is frozen and hardened, and the micro motor drives the tissue sampling head to rotate and cut the hardened tissue through the flexible transmission shaft. The application integrates the low-temperature hardening and the rotating cutting functions in a single slender instrument, solves the problem that the sample quality is unstable due to the size limitation of the channel under the guidance of the ultrasonic endoscope, and improves the success rate of biopsy diagnosis.

Description

Technical Field

[0001] This invention relates to the field of cavity tissue biopsy needle technology, and more particularly to a cryobiopsy needle for natural cavity tissue suitable for endoscopic ultrasound. Background Technology

[0002] Endoscopic ultrasound-guided fine-needle aspiration biopsy is currently an important method for obtaining tissue samples from deep lesions such as the mediastinum and pancreas. This technique involves inserting an endoscopic ultrasound device into the body through natural cavities. Under real-time ultrasound guidance, the biopsy needle is advanced through the working channel of the endoscope to the target lesion for puncture and sampling. Compared to percutaneous puncture, it has unique advantages such as less trauma, less patient discomfort, and the ability to reach deep anatomical locations.

[0003] However, due to the strict limitations of the working channel diameter of endoscopic ultrasound, the outer diameter of the biopsy needle must be controlled within 2.8 mm. Such a small needle makes it difficult to obtain sufficient tissue samples; in most cases, only cytological debris is obtained, failing to yield complete tissue strips, which is insufficient to meet the sample volume requirements for accurate pathological classification and gene testing. Lymph nodes or tumor tissues are often firm, richly vascularized, or contain necrotic areas. During routine puncture sampling, the tissue is prone to slippage and displacement, making it difficult for the needle to effectively penetrate. Furthermore, bleeding during the puncture process dilutes the sample, resulting in the extraction of mostly blood or necrotic tissue rather than viable tumor tissue with diagnostic value, leading to a high diagnostic failure rate.

[0004] Existing technologies include solutions for low-temperature assisted sampling, but these solutions are all based on percutaneous puncture pathways. The size and rigidity requirements of the instruments are completely incompatible with the flexible endoscopic environment of natural cavities. Alternatively, they employ a separate design for the cryoprobe and biopsy needle, requiring two separate entries and exits from the endoscopic channel to complete cryofixation and puncture sampling, which is cumbersome and increases the risk of intraoperative bleeding and tissue damage. Summary of the Invention

[0005] The purpose of this application is to address the problems existing in the prior art by proposing a transoral cryobiopsy needle for ultrasound endoscopy that is specifically designed for the working environment of ultrasound endoscopy, integrates moderate tissue sclerotherapy function with efficient mechanical sampling function into a single slender instrument, and can be completed in one operation through a natural cavity.

[0006] The technical solution of this application: A cryobiopsy needle for natural cavity tissues suitable for endoscopic ultrasound, comprising an operating handle, a flexible outer sheath extending distally from the operating handle, and further comprising: A gas supply line and a flexible drive shaft are coaxially arranged inside a flexible outer tube. A refrigeration unit and a tissue sampling head are coaxially arranged at the distal end of the flexible outer tube. The tissue sampling head can extend or retract axially relative to the front refrigeration unit. The gas supply line is connected to the refrigeration unit. The flexible drive shaft is fixedly connected to the tissue sampling head. The gas source interface installed in the operating handle, the gas control valve that controls the opening and closing of the gas source interface, and the carbon dioxide cylinder that can be interchangeably connected to the gas source interface. The micro motor installed inside the operating handle and the control button for starting and stopping the sampling micro motor are connected to the flexible transmission shaft via a transmission assembly.

[0007] Optionally, the outer diameter of the flexible outer sleeve is not greater than 2.6 mm and the length is not less than 1050 mm.

[0008] Optionally, the front-end cooling unit includes a miniature expansion cavity utilizing the Joule-Thomson effect to reduce the temperature of the contact surface as gas flows through it.

[0009] Optionally, a return air pipe is connected to the micro expansion chamber, and the air supply line is located inside the return air pipe and extends into the micro expansion chamber, for the purpose of returning carbon dioxide passing through the micro expansion chamber to the operating handle for discharge.

[0010] Optionally, it may also include a propulsion structure that controls the tissue sampling head to extend or retract axially relative to the front-end cooling unit.

[0011] Optionally, the propulsion structure includes a first sealing ring fixedly installed inside the flexible outer tube and a second sealing ring fixedly installed on the tissue sampling head, with a sealed air cavity formed between the first sealing ring and the second sealing ring. The first sealing ring is provided with an air inlet hole, and a gas gap is formed between the flexible outer sleeve and the flexible drive shaft for inputting gas into the sealed air chamber at the end of the operating handle.

[0012] Optionally, the tissue sampling head is a sharp rotary cutting needle with an annular cutting edge at its distal end and a sample receiving groove formed inside.

[0013] Optionally, the tissue sampling head is provided with multiple grooves, which divide the front end of the tissue sampling head into multiple cutting blades. The front ends of the multiple cutting blades form either a flat circle or a serrated ring.

[0014] Optionally, a compression block is fixedly installed on the cutting blade, the compression block has a first inclined surface, and a limiting block is installed inside the front end of the flexible outer sleeve. The limiting block has a second inclined surface that cooperates with the first inclined surface, which is used to apply a radial contraction force to the cutting blade.

[0015] Optionally, the outer surface of the tissue sampling head is provided with laser pits to enhance the imaging effect under ultrasound imaging.

[0016] In summary, this application includes at least one of the following beneficial technical effects: This application achieves moderate cryo-hardening of the target tissue surface through the Joule-Thomson effect, which increases tissue fragility and causes capillary contraction. This solves the problems of insufficient sampling and sample dilution caused by blood in traditional fine needle biopsy due to the toughness of the tissue and rich blood supply, and significantly improves the success rate of histological diagnosis through natural cavity biopsy. Furthermore, cryo-curing and rotary cutting are coaxially integrated into a single slender and flexible instrument, enabling seamless operation of microscopic positioning, cryo-curing, active clamping to prevent detachment, rotary cutting, and sample retrieval. This avoids the cumbersome operation of changing instruments under the microscope and the risk of complications such as bleeding and airway damage caused by repeated entry and exit. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of a transoral tissue cryobiopsy needle; Figure 2 This is a schematic diagram of the internal structure of the front end of the flexible outer sleeve; Figure 3 This is a schematic diagram of the structure of the tissue sampling head.

[0018] Reference numerals: 1. Operating handle; 2. Flexible outer sleeve; 3. Gas source interface; 4. Gas control valve; 5. Micro motor; 6. Control button; 7. Gas supply line; 8. Flexible drive shaft; 9. Transmission assembly; 10. Carbon dioxide cylinder; 11. Tissue sampling head; 12. Refrigeration unit; 13. Micro expansion chamber; 14. Return gas pipe; 15. First sealing ring; 16. Second sealing ring; 17. Air inlet; 18. Sealed gas chamber; 19. Gas gap; 20. Groove; 21. Cutting blade; 22. Extrusion block; 23. First inclined surface; 24. Limiting block; 25. Second inclined surface. Detailed Implementation

[0019] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0020] Example: Figure 1 and Figure 2As shown, this application proposes a transoral cryobiopsy needle for endoscopic ultrasound, comprising an operating handle 1, a flexible outer tube 2 extending distally from the operating handle 1, and an air supply line 7 and a flexible drive shaft 8 coaxially arranged within the flexible outer tube 2. The distal end of the flexible outer tube 2 is coaxially provided with a cooling unit 12 and a tissue sampling head 11. The tissue sampling head 11 can extend or retract axially relative to the front cooling unit 12. The air supply line 7 is connected to the cooling unit 12, and the flexible drive shaft 8 is fixedly connected to the tissue sampling head 11. The working channel diameter of the endoscopic ultrasound is typically 2.0 mm or 2.8 mm, and the outer diameter of the flexible outer tube 2 is no greater than 2.6 mm, ensuring it can accommodate a 2.8 mm working channel and providing sufficient layout space for the internally coaxially arranged air supply line 7 and flexible drive shaft 8. Its length of no less than 1050 mm ensures that the biopsy needle can reach deep lesions such as those in the mediastinum from the oral cavity through the pharynx and trachea.

[0021] The gas supply line 7 is responsible for delivering the refrigerant to the front-end refrigeration unit 12, and the flexible drive shaft 8 is responsible for transmitting the rotational torque at the operating handle 1 to the distal tissue sampling head 11. During operation, the refrigeration unit 12 first freezes and hardens the target tissue. After the tissue becomes brittle, the tissue sampling head 11 extends to cut. Through the collaborative working mode of hardening before cutting, the clinical pain point of traditional biopsy needles being unable to obtain complete tissue strips due to the toughness and elasticity of the tissue is solved.

[0022] The tissue sampling head 11 is a sharp rotating cutting needle with an annular cutting edge at its distal end and a sample receiving groove inside. The outer surface of the tissue sampling head 11 is provided with laser pits to enhance the imaging effect under ultrasound. The laser pits create a micro-rough structure on the outer surface of the needle. When ultrasound waves are incident, diffuse reflection occurs, and a considerable portion of the sound waves return to the probe along the original path, forming bright hyperechoic spots on the image. This allows doctors to track the position and orientation of the tissue sampling head 11 in real time and clearly, achieving precise puncture.

[0023] Furthermore, the biopsy needle also includes a gas source interface 3 installed in the operating handle 1, a gas control valve 4 for controlling the opening and closing of the gas source interface 3, and a carbon dioxide cylinder 10 that can be interchangeably connected to the gas source interface 3. The front-end cooling unit 12 includes a miniature expansion chamber 13 that utilizes the Joule-Thomson effect to reduce the temperature of the contact surface when gas flows through it. High-pressure carbon dioxide gas enters the gas supply line 7 through the gas source interface 3. When it reaches the miniature expansion chamber 13 of the front-end cooling unit 12, the gas undergoes a sudden increase in volume and a sharp drop in pressure, resulting in a Joule-Thomson effect. The effect, namely throttling expansion and heat absorption, rapidly reduces the temperature of the metal outer wall of the micro-expansion chamber 13 to the range of -20℃ to -40℃; it can only act on the surface layer of 1-2mm to achieve temporary hardening. At the same time, the low temperature causes capillary contraction, significantly reducing bleeding during the cutting process and avoiding blood dilution of the sample. The carbon dioxide cylinder 10 is a small medical-grade portable cylinder that can be interchangeably connected to the gas source interface 3. It eliminates the need for the bulky liquid nitrogen tank or freezing host required by traditional freezing equipment, greatly reducing equipment costs and operating thresholds, and facilitating rapid deployment in endoscopic operating rooms.

[0024] The miniature expansion chamber 13 is connected to a return air pipe 14. The air supply pipe 7 is located inside the return air pipe 14 and extends into the miniature expansion chamber 13. This allows the carbon dioxide passing through the miniature expansion chamber 13 to flow back to the operating handle 1 for discharge. After the carbon dioxide gas has completed expansion and heat absorption, it has become a low-pressure, room-temperature state. After circulating and being discharged from the miniature expansion chamber 13, it flows back to the operating handle 1 along the return air pipe 14 and is finally discharged into the operating room ambient air from the exhaust port on the operating handle 1. The high-pressure carbon dioxide is never directly sprayed onto human tissue at the front end, eliminating the risk of gas embolism and tissue emphysema. Furthermore, the gap between the air supply pipe 7 and the flexible drive shaft 8 is used as the return air channel, eliminating the need for an additional independent return pipe and effectively achieving air circulation within the flexible outer sleeve 2 with a limited diameter.

[0025] Furthermore, the biopsy needle in this embodiment also includes a micro motor 5 installed inside the operating handle 1 and a control button 6 for controlling the start and stop of the sampling micro motor 5. The output shaft of the micro motor 5 is connected to the flexible transmission shaft 8 through the transmission component 9. The flexible transmission shaft 8 is a helical spring tube structure, which is made of high carbon steel wire wound in layers in opposite directions. It has both good flexibility and sufficient torsional stiffness. Its flexibility allows it to bend along with the flexible outer tube 2 and smoothly pass through the multiple bends of the human body's natural cavities. Its torsional stiffness ensures that the rotational torque output by the micro motor 5 can be effectively transmitted to the distal tissue sampling head 11 over a distance of more than 1 meter, driving it to perform high-speed rotational cutting.

[0026] The motor is placed at the end of the handle and transmits power over a long distance through the flexible transmission shaft 8. The control button 6 is set on the operating handle 1 in a position that is convenient for one-handed operation. This allows the operator to control the start and stop of the motor while holding the handle, realizing a continuous one-handed operation process of microscopic positioning, cryo-hardening, rotary cutting and sample recovery, avoiding the tediousness and risks of changing instruments under the microscope.

[0027] like Figure 1 and Figure 2 As shown, in this embodiment, the transcavitary tissue cryobiopsy needle also includes a propulsion structure. The propulsion structure controls the axial extension or retraction of the tissue sampling head 11 relative to the front-end cooling unit 12. The propulsion structure includes a first sealing ring 15 fixedly installed inside the flexible outer tube 2 and a second sealing ring 16 fixedly installed on the tissue sampling head 11. A sealed air chamber 18 is formed between the first sealing ring 15 and the second sealing ring 16. By filling the sealed air chamber 18 with gas to increase its pressure, the air pressure pushes the second sealing ring 16 to slide distally relative to the first sealing ring 15. Since the second sealing ring 16 is fixedly installed on the tissue sampling head 11, the tissue sampling head 11 extends forward out of the cooling unit 12, and its annular cutting edge at the front end can pierce the cryo-hardened target tissue for cutting and sampling. The operating handle 1 is provided with a miniature air pump or air pressure control interface that communicates with the sealed air chamber 18. By controlling the input air pressure, the extension speed and stroke of the tissue sampling head 11 can be precisely adjusted.

[0028] The first sealing ring 15 is provided with an air inlet 17, and a gas gap 19 is formed between the flexible outer sleeve 2 and the flexible drive shaft 8. This gas gap 19 is used to input gas into the sealed air chamber 18 at the end of the operating handle 1. The gas gap 19 serves as a gas supply channel to deliver driving gas to the sealed air chamber 18 in the near-end region and as an exhaust gas return channel in the far-end region. This multi-purpose design of one gap saves the radial space inside the flexible outer sleeve 2 to the maximum extent.

[0029] A flexible elastic repositioning element, such as an elastic pull rope, can be installed between the tissue sampling head 11 and the flexible outer sleeve 2. When the pressure inside the sealed air chamber 18 decreases, the elastic repositioning element pulls the tissue sampling head 11 back into the cooling unit 12 by its own elastic restoring force, thus completing the sealing and protection of the sample.

[0030] like Figures 1 to 3As shown, in this embodiment, the tissue sampling head 11 is provided with multiple grooves 20, which divide the front end of the tissue sampling head 11 into multiple cutting blades 21. The front ends of the multiple cutting blades 21 form either a flat circle or a serrated ring. A squeezing block 22 is fixedly installed on the cutting blade 21. The squeezing block 22 is provided with a first inclined surface 23. A limiting block 24 is installed inside the front end of the flexible outer tube 2. The limiting block 24 is provided with a second inclined surface 25 that cooperates with the first inclined surface 23, which is used to apply a radial contraction force to the cutting blade 21. When the tissue sampling head 11 extends outward under pneumatic propulsion, the squeezing block 22 fixed on the cutting blade 21 moves forward, and the first inclined surface 23 on it gradually approaches the second inclined surface 25 on the limiting block 24. When the tissue sampling head 11 extends to the end of the cutting stroke and the cutting is completed, the first inclined surface 23 and the second inclined surface 25 begin to contact and slide relative to each other. Since the position of the second inclined surface 25 is fixed, the first inclined surface 23 is forced to slide inward along the inclined surface, applying a radially inward contraction and extrusion force to the cutting blade 21, causing multiple cutting blades 21 to shrink inward synchronously. The function of the groove 20 is to provide the cutting blade 21 with the deformation space for inward contraction. Without the groove 20, the continuous tubular structure has almost no radial contraction capability. At the same time, the through groove 20 reduces the cross-sectional stiffness of the cutting blade 21, so that it can undergo elastic inward deformation with less resistance when subjected to the pressure of the inclined surface. After the cutting blade 21 retracts inward, its inner wall applies a circumferential clamping force to the tissue core in the sample receiving groove, firmly fixing the tissue core inside the tissue sampling head 11. In addition, the tissue core is in a low-temperature state after freeze-hardening, and there is a temperature difference between it and the metal wall of the sampling head. As the temperature rises during the needle withdrawal process, the slight thermal expansion of the tissue core causes it to partially embed into the groove 20, further increasing the mechanical interlock between the tissue core and the inner wall of the tissue sampling head 11, effectively preventing the tissue core from slipping off due to gravity or friction of the tube wall during the retraction of the sampling head into the outer tube.

[0031] Working principle: The operator connects the carbon dioxide cylinder 10 to the gas source interface 3, inserts the flexible outer tube 2 into the body through the working channel of the ultrasound endoscope, and, under the guidance of ultrasound imaging, brings the front-end cooling unit 12 into contact with the target tissue surface. Pressing the gas control valve 4, the high-pressure carbon dioxide reaches the micro-expansion chamber 13 of the front-end cooling unit 12 through the gas supply line 7, and the Joule-Thomson effect occurs, rapidly absorbing heat and lowering the temperature of the outer wall of the cooling unit 12 to -20℃ to -40℃. Through heat transfer, the extracellular fluid of the contact area tissue undergoes micro-crystallization, surface hardening, and capillary contraction. After 5 to 7 seconds, the gas control valve 4 is released to stop the cooling. The low-pressure exhaust gas is discharged through the air hole 13 on the micro expansion chamber 13, flows back to the operating handle 1 through the return air gap 14 between the gas supply line 7 and the flexible drive shaft 8, and is discharged to the outside. Then, gas is filled into the sealed air chamber 18 through the air pressure control interface at the end of the operating handle 1. The air pressure pushes the second sealing ring 16 to drive the tissue sampling head 11 to extend out of the cooling unit 12. The annular cutting edge at the front end of the head penetrates the hardened tissue surface. At the same time, the control button 6 is pressed to start the micro motor 5. The micro motor 5 drives the flexible drive shaft 8 to rotate at high speed through the transmission component 9. The flexible drive shaft 8 transmits the torque to the tissue sampling head 11 to make it rotate synchronously, and cuts and cores the hardened and brittle tissue. When the tissue sampling head 11 extends to the cutting end, the first inclined surface 23 on the extrusion block 22 contacts the second inclined surface 25 on the limiting block 24 and slides relative to each other, applying a radially inward contraction extrusion force to the multiple cutting blades 21, causing the cutting blades 21 to retract inward and clamp the tissue core in the sample receiving groove. At the same time, during the freezing and heating process, the tissue micro-expansion embeds into the groove 20 to form a mechanical interlock, providing double protection against sample detachment. Subsequently, the air pressure inside the sealed air chamber 18 is released, the elastic reset member pulls the tissue sampling head 11 back into the cooling unit 12, and the flexible outer tube 2 is withdrawn from the body as a whole, and the sample is taken out for testing.

[0032] The above specific embodiments are merely several optional embodiments of the present invention. Based on the technical solutions of the present invention and the relevant teachings of the above embodiments, those skilled in the art can make various alternative improvements and combinations to the above specific embodiments.

Claims

1. A cryobiopsy needle for natural cavity tissue examination suitable for endoscopic ultrasound, comprising an operating handle (1) and a flexible outer sheath (2) extending distally from the operating handle (1), characterized in that, Also includes: A gas supply line (7) and a flexible drive shaft (8) are coaxially arranged inside a flexible outer tube (2). A refrigeration unit (12) and a tissue sampling head (11) are coaxially arranged at the far end of the flexible outer tube (2). The tissue sampling head (11) can extend or retract axially relative to the front-end refrigeration unit (12). The gas supply line (7) is connected to the refrigeration unit (12). The flexible drive shaft (8) is fixedly connected to the tissue sampling head (11). Gas source interface (3) installed in operating handle (1), gas control valve (4) controlling the opening and closing of gas source interface (3), and carbon dioxide cylinder (10) replaceably connected to gas source interface (3). The micro motor (5) installed inside the operating handle (1) and the control button (6) for controlling the start and stop of the sampling micro motor (5) are connected to the flexible transmission shaft (8) through the transmission assembly (9).

2. The transoral cryobiopsy needle for endoscopic ultrasound as described in claim 1, characterized in that, The outer diameter of the flexible outer sleeve (2) is no greater than 2.6 mm and the length is no less than 1050 mm.

3. The transoral cryobiopsy needle for endoscopic ultrasound as described in claim 1, characterized in that, The front-end cooling unit (12) includes a micro-expansion cavity (13) utilizing the Joule-Thomson effect to reduce the temperature of the contact surface as gas flows through it.

4. The transoral cryobiopsy needle for endoscopic ultrasound as described in claim 3, characterized in that, The micro expansion chamber (13) is connected to a return air pipe (14), and the air supply pipe (7) is located inside the return air pipe (14) and extends into the micro expansion chamber (13) to allow carbon dioxide passing through the micro expansion chamber (13) to flow back to the operating handle (1) for discharge.

5. The transoral cryobiopsy needle for endoscopic ultrasound as described in claim 1, characterized in that, It also includes a propulsion structure that controls the tissue sampling head (11) to extend or retract axially relative to the front-end cooling unit (12).

6. A transoral cryobiopsy needle for endoscopic ultrasound as described in claim 5, characterized in that, The propulsion structure includes a first sealing ring (15) fixedly installed inside the flexible outer tube (2) and a second sealing ring (16) fixedly installed on the tissue sampling head (11), with a sealed air cavity (18) formed between the first sealing ring (15) and the second sealing ring (16). The first sealing ring (15) is provided with an air inlet (17), and a gas gap (19) is formed between the flexible outer sleeve (2) and the flexible transmission shaft (8) for inputting gas into the sealed air chamber (18) at the end of the operating handle (1).

7. The transoral cryobiopsy needle for endoscopic ultrasound as described in claim 1, characterized in that, The tissue sampling head (11) is a sharp rotating cutting needle tube with an annular cutting edge at its distal end and a sample receiving groove formed inside.

8. A transoral cryobiopsy needle for endoscopic ultrasound as described in claim 7, characterized in that, The tissue sampling head (11) is provided with multiple grooves (20), which divide the front end of the tissue sampling head (11) into multiple cutting blades (21). The front ends of multiple cutting blades (21) form either a flat circle or a serrated ring.

9. A transoral cryobiopsy needle for endoscopic ultrasound as described in claim 8, characterized in that, An extrusion block (22) is fixedly installed on the cutting blade (21). The extrusion block (22) has a first inclined surface (23). A limiting block (24) is installed inside the front end of the flexible outer sleeve (2). The limiting block (24) has a second inclined surface (25) that cooperates with the first inclined surface (23) to apply a radial contraction force to the cutting blade (21).

10. A transoral cryobiopsy needle for endoscopic ultrasound as described in claim 1, characterized in that, The outer surface of the tissue sampling head (11) is provided with laser pits to enhance the imaging effect under ultrasound imaging.

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