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JP-7855623-B2 - Method and apparatus for laser lithotripsy

JP7855623B2JP 7855623 B2JP7855623 B2JP 7855623B2JP-7855623-B2

Inventors

  • グレゴリー・ビー・アルトシュラー
  • アナスタシア・コヴァレンコ
  • ヴィクトリア・ヴィンニチェンコ
  • イリヤ・ヤロスラフスキー

Assignees

  • アイピージー フォトニクス コーポレーション

Dates

Publication Date
20260508
Application Date
20240305
Priority Date
20180718

Claims (20)

  1. A laser system for treating kidney stones in living organisms, A laser for emitting radiation in a wavelength range, wherein the wavelength range is between 1.908 micrometers and 1.96 micrometers; An optical fiber for transmitting radiation from the laser to the calculus; A power supply that provides current to drive the laser; A control signal is provided to the power supply such that the laser emits a waveform having a first subpulse and a second subpulse; Equipped with, A laser system in which the first subpulse promotes the formation of vapor bubbles between the optical fiber and the calculus, thereby reducing the retraction of the calculus, and the second subpulse excises the calculus.
  2. The laser system according to claim 1, wherein the first subpulse has an energy in the range of 0.02 joules to 0.15 joules and a peak power in the range of 50 W to 500 W.
  3. The laser system according to claim 2, wherein the first subpulse has an energy in the range of about 0.05 joules to about 0.1 joules and a peak power in the range of 50 W to about 300 W.
  4. The laser system according to claim 1, wherein the second subpulse has an energy in the range of about 0.1 joules to about 10 joules and a peak power in the range of about 300 W to about 20,000 W.
  5. The laser system according to claim 1, wherein the laser is selected from the group including Tm: fiber laser, Tm: YAG laser, Tm: YAP laser, Tm: LuAG laser, Tm: LuF laser, Tm: LuAP laser, and combinations thereof.
  6. The laser system according to claim 1, wherein the second subpulse is initiated when the pressure inside the vapor bubble decreases or becomes negative, thereby generating a stone absorption effect.
  7. The laser system according to claim 6, wherein the time interval between the first subpulse and the second subpulse varies in the range of approximately 50 microseconds to approximately 900 microseconds.
  8. A laser system for treating kidney stones in living organisms, A laser for emitting radiation in a wavelength range, wherein the wavelength range is between 1.908 micrometers and 1.96 micrometers; An optical fiber for transmitting radiation from the laser to the calculus; A power supply that provides current to drive the laser; A control signal is provided to the power supply so that the laser emits pulses having a first part and a second part; Equipped with, A laser system in which the first part reduces water between the optical fiber and the calculus by forming steam bubbles, heats the calculus, and reduces the retraction of the calculus, and the second part reduces the size of the calculus.
  9. The laser system according to claim 8, wherein the first portion of the pulse has a power between 50 W and 200 W and a duration between approximately 0.1 milliseconds and approximately 10 milliseconds.
  10. The laser system according to claim 8, wherein the first portion of the pulse has a laser power between 400 W and 20,000 W, and a duration between approximately 0.5 milliseconds and approximately 20 milliseconds.
  11. The laser system according to claim 8, wherein the first portion of the pulse includes a value between 10% and 70% of the total energy of the pulse.
  12. The laser system according to claim 8, wherein the power of the first portion of the pulse is selected from the group including a function that does not decrease monotonically, a function that increases from a minimum level to a maximum level, a constant function, and combinations thereof.
  13. The laser system according to claim 8, wherein the laser is selected from the group including a Tm fiber laser, a Tm:YAG laser, a Tm:YAP laser, a Tm:LuAG laser, a Tm:LuF laser, a Tm:LuAP laser, and combinations thereof.
  14. The laser system according to claim 8, further comprising a controller for generating the control signal, wherein the controller determines the duration of the first portion of the laser pulse based on thermal radiation from the calculus.
  15. The laser system according to claim 14, wherein the optical fiber acquires thermal radiation from the calculus for use by the controller.
  16. A laser system for treating kidney stones in living organisms, A controller that outputs a control signal indicating a desired laser pulse shape including a first subpulse and a second subpulse; A power supply that provides variable power output in response to the reception of the aforementioned control signal; A laser connected to the power supply for emitting radiation according to the desired laser pulse shape, the laser having a wavelength range between 1.908 micrometers and 1.96 micrometers; Equipped with, The second subpulse has a total energy greater than the total energy of the first subpulse, The duration of the second subpulse is variable and determined by the controller. A laser system in which the first subpulse promotes the formation of vapor bubbles between the laser and the gallstone, thereby reducing the retreat of the gallstone, and the second subpulse excises the gallstone.
  17. The laser system according to claim 16, wherein the desired laser pulse shape is repeatedly applied to the calculus with a pause in between.
  18. The laser system according to claim 16, wherein the desired laser pulse shape includes the peak power of the second subpulse, which is an input to the controller for determining the duration of the second subpulse.
  19. The laser system according to claim 16, wherein the duration of the first subpulse is predetermined.
  20. The laser system according to claim 16, wherein the first subpulse vaporizes the fluid on the calculus.

Description

This disclosure generally relates to methods and laser systems for treating litholiths in the human or animal body, which increase the speed of litholith treatment according to various surgical procedures by controlling the temporal structure of the laser power. In particular, the present invention relates to methods and laser systems for treating litholiths with laser pulses having an improved temporal structure through modulation of pulse shape, in addition to pulse energy, peak power, and repetition rate. Pulsed laser sources may be used in lithotripsy to remove stones in humans and animals. Stones (also referred to herein as litholiths) are coagulated bodies of material that can form in the organs or ducts of the body. Urinary stones include nephroliths (also called intranephroliths or nephroliths) and bladder stones (also called intrabladder stones or bladder stones), and may have any one of several compositions, including mixed compositions. The main composition often includes calcium oxalate, calcium phosphate, magnesium ammonium phosphate, diammonium calcium phosphate, magnesium phosphate, cysteine, uric acid or urate, and xanthine. Stones of the gallbladder and bile ducts are called gallstones and arise mainly from bile salts and cholesterol derivatives. Stones can also form in other parts of the body, including the nasal passages, gastrointestinal tract, salivary glands, tonsils, and veins. Laser lithotripsy is a method of using lasers to induce the fracture of stones through various mechanisms. Typically, a fiber optic cable, traveling along the long axis of a rigid, flexible, or rib-shaped endoscope, transmits the laser beam for lithotripsy. The stones can be broken down (fragmented) into particles between 1 and 3-4 mm in size, which can then be removed through the working channel of a rigid instrument using a basket or similar device. Alternatively, the stones can be broken down into smaller particles (size <1 mm) in a process called dusting. A subdivision of dusting known as microdusting (particles <0.25 to 0.5 mm, depending on the stone composition and the shape of the dust particles) results in fragments small enough to be removed by a urinary flow or by a standard perfusion supplied by a water/saline bag suspended at a height of approximately 40 cm. Vaporization down to the molecular level is also possible. The efficiency of ablation depends on the conditions at the treatment site and can be substantially lower for large stones or when treating multiple stones in a single procedure. This problem is more typical for the treatment of large and multiple kidney stones by flexible ureteroscopy when the goal is to complete stone dusting in both contact and non-contact modes during surgery. Another problem is the movement of the stone during treatment due to recession. Recession is caused by the following phenomena: Light energy absorbed by water in the gap between the fiber and the stone generates a hydrostatic wave, pushing the stone away from the tip of the fiber. When laser energy is absorbed by the stone and stone ablation occurs, the rebound momentum of the ablation also causes the stone to displace away from the fiber. Recession prolongs the surgical time and makes it difficult for the surgeon to complete stone fragmentation or dusting and achieve a result free of residual stone particles. Increasing the average laser power and treatment time to compensate for the low ablation rate may be limited by the increased risk of soft tissue damage. Several surgical techniques are known for performing laser lithotripsy, based, for example, on the relative position and displacement of the fiber tip and the stone to be treated. These techniques generally fall into one of the following categories: contact lithotripsy, semi-contact scanning (dancing), and non-contact (popcorn) techniques. When using lithotripsy, the fiber tip is positioned in contact with the center of the stone, and laser power is delivered to the stone until macro-fractures and fragmentation occur. In lithotripsy, the laser power is applied to a small area for a relatively long period of time. Such a mode of operation results in relatively deep drill holes and thermomechanical stress that induces macro-fractures in the stone. In the scanning technique, the fiber moves continuously across the stone surface in near-contact (0–1 mm distance) with the stone. Each pass across the stone surface results in the removal (excision) of a thin layer of stone. This technique is preferred for excising (dusting) the stone into smaller fragments. If the possibility of operation in contact or near-contact mode due to retraction is unacceptable, a non-contact technique is used for treating stone fragments (typically less than 3 mm in size). In the non-contact technique, the fiber is positioned in a fixed location close to the target stone fragment, and the laser is irradiated in a non-contact manner. As a result of vaporization and bubble implosion, wa