Optimization of BPH treatment using HOELP (Holmium Laser Enucleation of the Prostate)

Abstract

To eliminate or reduce fiber burn-back, to facilitate cauterization and solidification, to obtain an excellent processing parameter, and to control formation and shapes of bubbles.SOLUTION: A laser device is configured to provide one or more laser pulses that are configured by a controller to have enough energy to form one or more steam bubbles in a liquid medium at a fiber distal delivery end. The one or more pulses are configured to perform the following with the controller: first, to form steam bubbles around a distal end of a distal end part of an endoscope and a distal delivery end of an optical fiber; second, to form second bubbles at a distal end of the first bubbles; and third, to expand the second bubbles so as to expand sufficient amount of a considerable part of the liquid medium from a space between the distal delivery end of the fiber and a target tissue when the first bubbles begin to collapse.SELECTED DRAWING: Figure 3B

Description

Technical Field

[0001] Related Applications This application claims priority to U.S. Provisional Application No. 62 / 649,930, filed Mar. 29, 2018, the entire content of which is incorporated herein by reference. This application also claims priority to and is a partial continuation of U.S. Patent Application No. 16 / 177,800, filed Nov. 1, 2018, the entire content of which is incorporated herein by reference.

[0002] [[ID=II]]Field of the Invention The present invention is directed to a laser device useful for treating benign prostatic hyperplasia (BPH), specifically, for example, a device useful for performing laser enucleation of the prostate (LEP), which is abbreviated as HoLEP when performed using a holmium laser device and ThuLEP when performed using a thulium laser device. The present invention may also be useful for performing laser ablation of the prostate (LAP), which is known as HoLAP when performed using a holmium laser.

[0003] The present invention relates to a laser energy source and to methods and devices for reducing attenuation of a laser beam that will pass through a liquid environment to a target tissue in laser lithotripsy, optical fiber back-burning, and reduction of target tissue posterior migration, LEP, as well as other related fields in which lasers are used in a liquid environment.

Background Art

[0004] Benign prostatic hyperplasia (BPH) has been successfully treated using the well-known laser enucleation procedure (known in the industry as "LEP"), which is a surgical procedure in which the growing prostate tissue (prostatic adenoma) is separated from the surrounding prostatic capsule and other organs such as the seminal cumulus and other landmarks by cutting the prostate without damaging the capsule itself. The separated tissue is usually cut into several small pieces, which are then pushed into the bladder. The pieces may then be shredded using a mechanical shredding device that breaks the pieces into pieces small enough to be removed from the body. A device such as the one described in the pending U.S. Patent Application No. 15 / 710,316, filed September 20, 2017, entitled "System and Method for Morcellation of Tissue" (this application is incorporated herein by reference in its entirety) may be suitable for performing this tissue removal operation. In addition, laser-based shredding devices may be employed. The entire surgery is performed using endoscopic techniques through natural body openings.

[0005] LEP surgery has been found to be very beneficial for patients because, unlike other types of surgery (such as TURP), it generally has a very low reoperation rate due to the fact that there is no prostate regrowth because all of the prostate tissue is removed. Due to the very low complication rate, patients recover faster and experience less pain than with some other surgeries.

[0006] In the first step of a typical LEP surgery, an incision may be made in the prostate tissue to reach the capsule. This is usually done in a predetermined position that helps the surgeon's orientation, such as the "1 o'clock" or "11 o'clock" positions. Some doctors make different incisions, such as the "5 o'clock" and "7 o'clock" positions, "12 o'clock" or others. After reaching the prostate-capsule boundary, the surgeon may fire a laser along the anatomical boundary between the prostate material and the capsule, thus creating a separation plane between the two.

[0007] During LEP surgery, the optical fiber is inserted through the working channel of the ureteroscope, as well as through the irrigation and visualization system. The working environment for the laser radiation emitted from the tip of the optical fiber toward the target tissue is therefore a liquid environment. Liquid environments tend to absorb light energy and can therefore affect both the adjacent liquid environment itself and the characteristics of the emitted laser beam reaching the target tissue. As described in the aforementioned U.S. Patent Application No. 16 / 177,800 and its incorporated references, considerable attention has been paid to the interaction between the laser beam and the surrounding liquid in the working environment, and how this enhances the effectiveness of the light energy in lithotomy and reducing posterior stone migration.

[0008] More specifically, several aspects of the incorporated references disclose the generation and control of vapor bubbles during lithotripsy in a liquid working environment due to their light energy absorption properties. The MOSES® effect is described and optimized in these documents, where a controlled amount of energy creates vapor bubbles that vaporize the liquid in the environment, and the remaining energy is then delivered through the vapor bubbles toward the target stone. Using and optimizing this laser-liquid interaction during LEP surgery by controlling different laser and beam characteristics to create bubbles that improve mechanical tissue separation is one aspect of the present invention.

[0009] As described in the aforementioned U.S. Patent Application No. 16 / 177,800, when a laser is emitted, it may create a vapor bubble in front of the fiber tip, the bubble being caused by the laser vaporizing liquid matter present in the area. In the lithotomy described in the aforementioned U.S. Patent Application No. 16 / 177,800, one or more vapor bubbles created by the laser device are used in such surgery to create a “pathway” for destroying or breaking down kidney stones or other abnormal growths that may be present and “floating” in, for example, the urinary tract, kidneys, or bladder. By vaporizing the liquid matter between the target object and the laser fiber tip that carries laser energy from, for example, a holmium laser, thulium laser, or erbium laser to the target stone, a more efficient procedure may be achieved because there is no liquid in the “pathway.” According to aspects of the present invention, a surgeon may create one or more bubbles with a laser in a liquid working environment during LEP surgery, and the vapor bubbles created by the laser pulse may be used to mechanically cut the prostate or separate the prostate from its capsule or other organs. Furthermore, the pathways of one or more bubbles to the target tissue allow for easier visual tracking of the laser-cut surface.

[0010] In LEP surgery, three terms may be relevant to this surgical procedure: 1. The aforementioned and incorporated techniques relating to the MOSES(trademark) effect and its optimization; 2. Photomechanical effect (in contrast to the MOSES(trademark) photomechanical effect in lithotomy on target tissue) where laser energy creates vapor bubbles, which are used to mechanically separate tissue by cavitation during their expansion or collapse, as discussed above in LEP surgery and according to the present invention; 3. Photothermal effect (again, in contrast to the MOSES(trademark) photothermal effect in lithotomy on target tissue) where laser energy is delivered directly to the tissue, causing thermal damage and thus creating an incision or producing a cauterizing or coagulation effect.

[0011] Figure 1 shows a typical instrument configuration in modern lithotomy. The instrument 100 includes an optical laser fiber or light guide 102 connected at its proximal end 104 to a laser source 106 which may be holmium, thulium, erbium, or other. The laser fiber or light guide 102 is passed through an endoscope 108, and its distal end or tip 110 extends outward from the distal end 112 of the endoscope. A normal mode pulse emits a continuous amount of energy from the distal end 110 of the fiber into the fluid environment surrounding the fiber and between the fiber and the target tissue 114. This emission causes the expansion of a growing bubble, which is later collapsed, typically resulting in the expansion of a symmetrical bubble 116 whose center is located around the fiber tip 110.

[0012] One problem associated with the configuration of this prior art shown in Figure 1 is the potential adverse effects that (one or more) bubbles may have on both the fiber tip and the distal end of the endoscope. As seen in Figure 1, the vapor bubble 116 expands not only in the direction of the target tissue but also posteriorly, and with its contained energy, this bubble can collide with the distal end of the endoscope, and during its collapse, it can even collide with the fiber or the ureteroscope itself, thus producing so-called "burnback" or degradation of the fiber. Fiber burnback is known as a condition that can cause degradation of the fiber tip to such an extent that it interferes with or at least makes the treatment parameters less efficient. Furthermore, the posterior development of the bubble represents a loss of light energy absorbed by the liquid but not improving the MOSES™ effect, thus reducing the efficiency of tissue treatment by reducing the energy available to affect the treatment of target tissue, such as prostate or urinary tract stones.

[0013] Therefore, it would be desirable to provide devices and methods for eliminating or reducing fiber burnback, which have the added benefit of reducing wear on the endoscope and providing more light energy to be delivered to the target tissue, as well as to promote cauterization and coagulation by utilizing the MOSES® effect to create and control bubbles that promote tissue separation. The present invention aims at least in part to this objective.

[0014] Furthermore, U.S. Patent Application No. 16 / 177,800, as mentioned above, describes a step 400 in relation to Figure 3B in which the user may select the number of “pulse pair” repetitions. The specification further describes this step 400 as the number of repetitions between pulse pairs, one of which may be a foam initiation pulse and the second may be a treatment pulse. It has been found that by manipulating the timing of the pulse pairs, better treatment parameters can be obtained. The present invention also aims at this objective.

[0015] Furthermore, while the aforementioned U.S. Patent Application No. 16 / 177,800 generally describes the fiber tip, it does not provide any further mechanisms for controlling the formation and shape of bubbles. The present invention also covers mechanisms for controlling the formation and shape of bubbles. [Overview of the project]

[0016] In one embodiment, a method for treating target tissue with a laser beam, wherein the target tissue is immersed in a liquid medium within a body lumen, the method includes providing a laser device for generating a laser beam; providing an endoscope configured to be introduced into a body lumen and having a distal end; providing an optical fiber or light guide configured to be housed within the endoscope and having a distal delivery end for guiding a laser beam to the target tissue, the distal delivery end protruding a certain distance from the distal end of the endoscope; and providing a controller for the laser device for generating one or more laser pulses substantially along the same longitudinal axis. In LAP surgery (laser ablation of the prostate), a lateral emission fiber or waveguide may be used. The controller provides one or more laser pulses to the laser device, and the controller configures the one or more laser pulses to have enough energy to form one or more vapor bubbles in a liquid medium at the distal end of the fiber, and the controller causes the one or more pulses to first form vapor bubbles distal to the distal end of the endoscope and around the distal end of the optical fiber or light guide, and second form a second vapor bubble distal to the first bubble, the second vapor bubble being at the distal end of the endoscope and the distal end of the optical fiber The device is configured to: form a second bubble distal to both distal delivery ends, and, thirdly, when the first bubble begins to collapse, inflate a second bubble to such an extent that it expands enough to displace a substantial portion of the liquid medium from the space between the distal delivery end of the fiber and the target tissue, with one or more pulses being delivered to the target tissue through the expanded second bubble, and the displacement of the second bubble away from the distal end of the endoscope and the distal delivery end of the optical fiber reduces wear and / or damage to one or more of the endoscope and the optical fiber.

[0017] In another embodiment, an apparatus for laser beam treatment of target tissue, in which the target tissue is immersed in a liquid medium within a body lumen, includes a laser device for generating a laser beam; an endoscope configured to be introduced into a body lumen and having a distal end; an optical fiber or light guide configured to be housed within the endoscope and having a distal delivery end for guiding the laser beam to the target tissue, the optical fiber or light guide projecting a certain distance from the distal end of the endoscope; and a controller for generating one or more laser pulses in the laser device substantially along the same longitudinal axis or alongside the same longitudinal axis. The laser device is configured to provide one or more laser pulses, and the controller is configured such that one or more laser pulses have sufficient energy to form one or more vapor bubbles in the liquid medium at the distal delivery end of the fiber. One or more pulses are configured by the controller to: firstly, cause vapor bubbles to form distal to the distal end of the endoscope and around the distal delivery end of the optical fiber or light guide; secondly, cause a second vapor bubble to form distal to the first bubble, the second vapor bubble being distal to both the distal end of the endoscope and the distal delivery end of the optical fiber; and thirdly, once the first bubble begins to collapse, inflate the second bubble to such an extent that it expands enough to displace a substantial portion of the liquid medium from the space between the distal delivery end of the fiber and the target tissue, with one or more pulses being configured to inflate the second bubble, which is delivered to the target tissue through the expanded second bubble. The displacement of the second bubble away from the distal end of the endoscope and the distal delivery end of the optical fiber reduces wear and / or damage to one or more of the endoscope and the optical fiber.

[0018] In a further embodiment, one or more laser pulses are two or more pulse trains, and the method further includes the step of a controller that selects the number of repetitions for the delivery of the two or more laser pulses. The method may also include selecting at least one of the following parameters through the controller: selecting the total energy of one or more pulses to be delivered to the target tissue; selecting the pulse length of one or more pulses to be delivered to the target tissue; selecting the pulse energy; selecting the time delay between one or more consecutive pulse trains; selecting the laser (wavelength) to be used for one or more pulses; selecting the size of the fiber; selecting the desired clinical outcome; and selecting the distance from the delivery end to the target tissue.

[0019] In yet another embodiment, the method may further include the steps of measuring the actual energy irradiated by the laser device, comparing the measured actual energy with a total energy selected by a controller, and, if the comparison demonstrates a difference between the measured actual energy and the total energy selected, the controller adjusting the energy or pulse length of any subsequent pulse to achieve the selected energy to be delivered to the target tissue. The target tissue may be tissue, organ, or formed calculus within the human body.

[0020] In some embodiments, the method may also include the step of selecting a type of optical fiber or optical guide to be used to irradiate the target tissue and placing it in the laser device. The type of optical fiber or optical guide includes at least one of the parameters of fiber diameter, fiber material, fiber numerical aperture, and shape of the distal delivery end. The step of selecting the distance from the delivery end to the target tissue may include the further step of measuring the distance and selecting the measured distance. The step of measuring the actual energy delivered by the laser is performed by a photodetector in the optical path of the laser radiation or in the optical path of the backscattered laser light from the target tissue.

[0021] In another embodiment, the step of the controller adjusting the energy is achieved by a closed-loop feedback circuit operably connected to the controller. The controller may intermittently recognize parameters related to the type of fiber installed in the laser device. The step of automatic recognition is performed by RFID identification tags installed on the transmission device and on the waveguide or optical fiber. The controller may indicate on a user interface associated with the controller whether the type of optical fiber is suitable for the selected treatment.

[0022] In one embodiment, a method for treating target tissue with a laser beam, wherein the target tissue is immersed in a liquid medium within a body lumen or the laser beam must traverse the liquid medium en route to the target tissue, comprises providing a laser device for generating a laser beam, providing an optical fiber or light guide having a distal delivery end for guiding the laser beam to the target tissue, and providing the laser device a controller for generating one or more laser pulses substantially along the same longitudinal axis or lateral to the same longitudinal axis, wherein the controller provides the laser device with a plurality of laser pulses, which are configured by the controller such that the plurality of laser pulses have sufficient energy to form one or more vapor bubbles in the liquid medium at the distal delivery end of the fiber, which may be selected by the controller such that the plurality of laser pulses inflate one or more vapor bubbles by an amount sufficient to displace a substantial portion of the liquid medium from the space between the delivery end of the fiber and the target tissue, which are delivered to the target tissue through one or more vapor bubbles, and the time intervals between adjacent pulses of the plurality of pulses are non-uniform. The procedure may be a prostate enucleation, in which one or more pulses may be configured first for mechanical tissue separation, followed by one or more pulses configured to incise the mechanically separated tissue. Alternatively, the procedure may be a lithotripsy to reduce the size of kidney stones, in which one or more pulses may be configured first to induce cavitation, which carries the stones in front of the laser fiber, followed by a series of low-energy, high-repetition-count pulses that result in stone dusting, which reduces the size of the kidney stones. Furthermore, the procedure may be a prostate enucleation or vaporization, in which one or more pulses may be configured first to perform one or more incisions or ablations of the target tissue, followed by one or more pulses configured to coagulate the tissue that has been incised or ablated.

[0023] In a further embodiment, the apparatus for treating target tissue with a laser beam, wherein the target tissue may be immersed in a liquid medium within a body lumen, or the laser beam must traverse the liquid medium en route to the target tissue, comprises a laser device for generating a laser beam, an optical fiber or light guide having a distal delivery end for guiding the laser beam to the target tissue, and a controller configured to cause the laser device to generate one or more laser pulses substantially along the same longitudinal axis or laterally, the controller further configured to cause the laser device to provide a plurality of laser pulses, the plurality of laser pulses configured by the controller to have sufficient energy to form one or more vapor bubbles in the liquid medium at the distal delivery end of the fiber, the plurality of laser pulses may be configured by the controller to inflate one or more vapor bubbles by an amount sufficient to displace a substantial portion of the liquid medium from the space between the delivery end of the fiber and the target tissue, the plurality of pulses delivered to the target tissue through one or more vapor bubbles, the time intervals between adjacent pulses of the plurality of pulses are non-uniform.

[0024] In another embodiment, the procedure may be a prostate enucleation, where one or more pulses are configured first for mechanical tissue separation, followed by one or more pulses configured to incise the mechanically separated tissue. In addition, the procedure may be a lithotripsy to reduce the size of kidney stones, where one or more pulses are configured first to induce cavitation, which carries the stones in front of a laser fiber or light guide, followed by a series of low-energy, high-repetition-count pulses resulting in stone dusting, which reduces the size of the kidney stones. The procedure may also be a prostate enucleation or vaporization, where one or more pulses are configured first to perform one or more incisions or ablations of the target tissue, followed by one or more pulses configured to coagulate the tissue after one or more incisions or ablations have been performed.

[0025] In a further aspect, an apparatus for treating a target tissue with a laser beam, where the target tissue is immersed in a liquid medium within a body lumen or the laser beam must cross a liquid medium on its way to the target tissue, includes a laser device for generating the laser beam, an endoscope configured to be introduced into the body lumen and having a distal end, and an optical fiber configured to be housed within the endoscope and having a distal delivery end for guiding the laser beam to the target tissue, the distal delivery end protruding a distance from the distal end of the endoscope. A tubular hollow choke may be configured to be installed at one of the distal delivery end of the optical fiber or light guide or the distal end of the endoscope, and the choke may be configured to shape a vapor bubble formed distally of one of the distal end of the endoscope or the distal end of the optical fiber or light guide when the laser device generates the laser beam. The tubular hollow choke may be one of a cylindrical shape or a frustum of a cone shape. Further, the taper may be either a taper shape that increases or decreases from the proximal end to the distal end of the frustum of a cone-shaped hollow choke.

Brief Description of the Drawings

[0026] [Figure 1] Shows a diagram of a prior art device. [Figure 2] Shows an embodiment of bubble formation of the present invention. [Figure 3A] Shows a series of bubble formations related to the present invention. [Figure 3B] Shows a series of bubble formations related to the present invention. [Figure 3C] Shows a series of bubble formations related to the present invention. [Figure 3D] Is a graphical representation of bubble formation in the present invention. [Figure 4A] Shows an embodiment of the timing of pulse formation in the present invention. [Figure 4B] Shows an embodiment of the timing of pulse formation in the present invention. [Figure 4C] Shows an embodiment of the timing of pulse formation in the present invention. [Figure 5A]This shows various chokes that may be used at the distal end of either an optical fiber or an endoscope. [Figure 5B] This shows various chokes that may be used at the distal end of either an optical fiber or an endoscope. [Figure 5C] This shows various chokes that may be used at the distal end of either an optical fiber or an endoscope. [Figure 5D] This shows various chokes that may be used at the distal end of either an optical fiber or an endoscope. [Modes for carrying out the invention]

[0027] Bubble manipulation to reduce burnback at the fiber tip and damage to the endoscope As described above, it may be desirable to be able to manipulate the formation of bubbles caused by the emission of a laser device so as to cause the "movement" of (one or more) bubbles formed "forward" (or otherwise away from the fiber tip) by a certain distance in front of the fiber, in order to reduce burnback, reduce endoscope wear, and make more efficient use of the photomechanical effects described above. One of the techniques disclosed in the aforementioned patent application, known in the industry as the MOSES® technique, generally involves generating two or more bubbles, the first of which may vaporize the fluid present, and the second of which may provide treatment to target tissue. However, it should be understood that the description provided hereby is not in any way limited to the disclosure and is not a substitute for a thorough re-examination and understanding of the aforementioned patent application.

[0028] Next, looking at Figure 2, this figure shows one embodiment of the present invention, in which the vapor bubble moves distally from a position where it strikes both the fiber tip and the endoscope as in Figure 1, to a position shown in Figure 2 where the bubble 202 moves away from the endoscope tip 200 and the fiber tip 204, and gets closer to the target tissue 206.

[0029] Thus, the bubble 202 is positioned to form further distally from both the endoscope and the fiber. As mentioned above with respect to Figure 1, the bubble tends to develop around the tip of the fiber. Since the bubble created by the laser also tends to collapse toward its center through cavitation, it can damage the tip of the fiber or the adjacent tip of the endoscope. The larger the bubble, the greater the potential for damage. The advantage of shifting the bubble formation site distally is that when the bubble collapses, it does not collapse on the tip of the fiber or endoscope, and can cause a stronger photomechanical effect on the target tissue. Another advantage is that the bubble does not collide with the endoscope 200 or cause burnback of the fiber tip 204, thus reducing the potential for damage and wear. Also, if the bubble collapses toward its center, which is located away from the fiber tip, this reduces burnback and degradation of the fiber tip due to the shock wave of the bubble collapse.

[0030] To achieve the above objective as shown in Figure 2, the following discussion may be a desirable procedure. As seen in Figure 3A, a first laser pulse is initiated through the fiber 300 to create a small bubble 302 around the tip 304 of the fiber 300. As seen in Figure 3B, after a time delay, a second laser pulse is initiated to create a second bubble 306 that forms distal to the first bubble 302. Then, as the first bubble 302 collapses, the second bubble 306 becomes larger in size. A larger second distal bubble, larger than the first proximal bubble, is a desirable outcome for pushing cavitation damaging forces away from the endoscope and the tip of the fiber. In this regard, as seen in Figure 3C, the bubble 306 does not touch the fiber tip 304 or the endoscope tip, or is not centered on the fiber tip 304 or the endoscope tip.

[0031] Next, referring to Figure 3D, the typical dynamics of a bubble over time are shown. The pressure inside the developed bubble is qualitatively represented by line a', and the diameter of the bubble is qualitatively represented by line b'. At the start of the bubble, the pressure inside the bubble is high, and it can be seen that it decreases as the diameter of the bubble increases. At some equilibrium point with the ambient pressure, the bubble stops growing, and the vapor inside begins to cool. This eventually leads to the opposite dynamics, where the diameter begins to decrease and the internal pressure begins to increase again. This process ends as cavitation. Initiating a first smaller bubble and a second larger "major" bubble is one aspect of the invention, as the first bubble is concentrated around the tip of the fiber, and the cavitation energy is stronger as the bubble gets larger. The pressure inside the second formed bubble is qualitatively represented by line a'', and the diameter of the bubble is qualitatively represented by line b''. Therefore, according to an aspect of the present invention, a first bubble is created, and then, with a specific time delay and within a specific time frame, a second bubble is created, and as a result, the increased pressure of the first bubble during its collapse promotes the expansion of the second bubble.

[0032] The above discussion and diagrams describe two pulses, but it should be understood that the regimen may also consist of three consecutive pulses. The first and second pulses may be used to form and maintain bubbles, and the third pulse may be used as the treatment pulse. However, the present invention is not limited to three pulses and may be any number determined by factors such as the type of treatment, the energy of each pulse, the liquid environment, and the distance from the fiber tip to the target tissue.

[0033] Therefore, as can be seen, by manipulating the bubble formation technique, degradation of the fiber tip and the distal tip of the endoscope is reduced while creating bubbles that enhance the efficiency of the photomechanical interaction between the target tissue and the laser, or the photothermal interaction in tissue ablation or coagulation.

[0034] Interleaving of laser pulse repetition rate In a current MOSES® system, as implemented by the assignee of the present invention, the laser may emit a laser pulse train, using the same settings for each pulse, using a constant number of repetitions, and as seen in Figure 4A, the symbol T in 400 represents the time between consecutive pulses 402a, 402b, and 402n. Thus, under these aforementioned parameters, identical pulse trains occur at equal time intervals. Therefore, each pulse may be started with the same energy setting, the same peak power (or pulse width), and, if a MOSES® mode is used, the same MOSES® mode parameters.

[0035] However, instead of implementing it using pulses of the same timing as in Figure 4A, the pulse regime may be constructed to generate periodic pulse train packets, as shown in Figure 4B, where each pulse in the packet may have different parameters, and the intervals between pulses in the packet may also be varied. Each pulse designated as pulse MOSES(trademark) 1, 2, and k in Figure 4B may differ from the others in the number of subpulses (typically, MOSES(trademark) is implemented with two subpulse regimens), total energy, energy distribution between subpulses, and time intervals between subpulses.

[0036] Interleaving, as described in relation to Figure 4B, allows for an optimized combination of different pulse mode properties to achieve tissue effects such as mechanical separation of tissue, thermal cauterization of tissue, or thermal coagulation of tissue, which is improved compared to what is possible with a sequence of uninterleaved identical pulses.

[0037] Furthermore, as shown in Figure 4C, it may be useful to provide a non-periodic laser activation process in which each pulse may have its own intrinsic parameters and the pulse intervals may be similarly varied. This variability may be useful depending on the type of treatment desired. MOSES® pulses may be used to optimize the amount of light energy delivered to a target tissue or liquid medium for the purpose of cauterization, coagulation, or producing a photomechanical effect on the target tissue. A pulse train may consist of one or more first subpulses configured to generate a first bubble centered on the tip of an optical fiber, followed by one or more second subpulses configured to generate a second bubble. The first bubble is spaced apart from the second bubble such that the center of the second bubble is longitudinally offset from the tip of the optical fiber. Thus, the collapse of the second bubble may reduce fiber burnback and increase mechanical separation of the target tissue. One or more first pulses may be generated with a laser having a first wavelength, and one or more second pulses may be generated with a laser having a second wavelength. According to one embodiment, the first laser wavelength and the second laser wavelength are the same and may be generated by the same type of laser, such as holmium, thulium, or erbium. According to another embodiment, the first laser wavelength and the second laser wavelength are different. For example, the first laser wavelength may be a thulium laser wavelength and the second laser wavelength may be a holmium laser wavelength.

[0038] For example, some possible uses of this technology include:

[0039] 1. Lithotripsy - Popcorn Mode. In this mode, fluid convection is used to transport the stones ahead of the fiber, and then the stones are broken up by laser pulses. Convection is caused by laser pulses and should have large bubbles in this case. Stone breakup is best performed by MOSES™ mode pulses, e.g., low energy high repetition rate "dusting mode" setting, which does not produce sufficient convection. Interleaved pulses optimized to induce cavitation, along with pulses optimized for stone dusting, can significantly improve popcorn or pop-dusting surgery.

[0040] 2. Enucleation of the prostate - Improved tissue separation. In this mode, several pulses can be positioned close together within the packet. Some pulses can be optimized to provide the best mechanical tissue separation (photomechanical effect), while subsequent pulses can be optimized for the best tissue cutting (photothermal effect). Thus, the first pulse "stretches" the tissue, preparing it for subsequent pulses and making the incision more effective.

[0041] 3. Enucleation or cauterization of the prostate - improves hemostasis. This combination can be used to treat vascular prostate. Some pulses of the packet will be optimized for the best tissue treatment (incision or cauterization), while subsequent pulses will be optimized for the best coagulation.

[0042] 4. Calculus treatment - Dynamic changes in pulse optimization (contact / distance / fragmentation / dusting), etc.

[0043] Foam molding element To date, many techniques have been described for controlling and customizing the formation of (one or more) bubbles suitable for a particular purpose. These have been primarily achieved through non-physical modifications, such as manipulating the timing of laser initiation. However, physical modifications to the laser device, specifically the distal end of the endoscope, may provide the ability to manipulate the shape, size, and other properties of the bubbles.

[0044] Next, Figures 5A to 5D show various types of “chokes” that may be attached to the distal end of the endoscope or the distal end of the fiber itself. The foam shaping elements may be configured to shape one or more bubbles created at the tip of the optical fiber during laser treatment in a liquid environment. Foam shaping elements such as foam shaping elements 502, 510, 512, and 514 may be installed or attached to the distal end of the endoscope 500 or the fiber 508 and have a proximal end 504 configured to connect to or engage with the distal end of the optical fiber 508 or an area adjacent to the distal end of the endoscope 500. The distal end of the fiber shaping element is configured to allow fluid communication between the internal cavity in the foam shaping element and the treatment environment.

[0045] During laser treatment, bubbles developing at the distal end of the optical fiber are restricted from expanding in certain dimensions and are allowed to expand freely in other dimensions. According to embodiments of the present invention shown in Figures 5A to 5D, bubble shaping elements 502, 510, 512, and 514 restrict one or more bubbles from expanding along an axis substantially perpendicular to the longitudinal axis 516 of the optical fiber, while allowing bubbles 600 to grow along the longitudinal axis 516 of the optical fiber.

[0046] The foam shaping element may have an expanded shape (502), a converging shape (510), a linear shape (512), a narrow cross-section (514), or a frustoconical shape, or other shapes for controlling the size and formation of the foam.

[0047] The foam shaping elements shown in Figures 5A-5D allow foam 600 to grow more along the axis connecting the distal end of the optical fiber to the target tissue, and restrict the growth of foam 600 along axes nearly perpendicular to this axis. Foam in a liquid environment is a more effective channel for delivering light energy to the target tissue due to its lower absorption than the surrounding liquid environment, and the foam shaping elements allow for an improvement in the ratio between the amount of energy required to create the foam and the longitudinal size of the foam. In this case, optimization means that less energy is "wasted" in developing the foam and growing it to reach the target tissue in order to produce the required MOSES® or other desired effect, and then more energy is available to be delivered into the target tissue through the foam in order to obtain the desired treatment effect.

[0048] Four different types of chokes are shown in Figures 5A–5D, but it is suggested that many other types are feasible. In addition, adjustable chokes may be implemented, which are almost identical to the adjustable chokes used in shotguns, thereby allowing the mechanism to be adjusted to change the shape of the choke to suit specific treatment parameters.

[0049] Embodiments of the present invention are described below. (Embodiment 1) Apparatus for laser beam treatment of target tissue, wherein the target tissue is immersed in a liquid medium within a body lumen, and the apparatus, A laser device for generating a laser beam, An endoscope configured to be introduced into the body lumen, wherein the endoscope has a distal end, An optical fiber configured to be housed in the endoscope and having a distal delivery end for guiding the laser beam to the target tissue, wherein the distal delivery end is an optical fiber that protrudes a certain distance from the distal end of the endoscope, The laser device includes a controller for generating multiple laser pulses substantially aligned along the same longitudinal axis, The laser device is configured to provide the plurality of laser pulses, and the controller is configured such that the plurality of laser pulses have sufficient energy to form a plurality of vapor bubbles in the liquid medium at the distal delivery end of the optical fiber. The plurality of laser pulses are controlled by the controller, Firstly, to form a first vapor bubble around the distal end of the endoscope and around the distal delivery end of the optical fiber, Secondly, the formation of a second vapor bubble distal to the first vapor bubble, wherein the second vapor bubble is located distal to both the distal end of the endoscope and the distal end of the optical fiber. Thirdly, once the first vapor bubble begins to collapse, the second vapor bubble is expanded so as to shift a portion of the liquid medium out of the space between the distal delivery end of the optical fiber and the target tissue, wherein the plurality of laser pulses are delivered to the target tissue through the expanded second vapor bubble. It is configured to do the following: The displacement of the second vapor bubble away from the distal portion of the endoscope and the distal delivery end of the optical fiber reduces wear and / or damage to one or more of the endoscope and the optical fiber. (Embodiment 2) An apparatus for treating target tissue with a laser beam, wherein the target tissue is immersed in a liquid medium within a body lumen, and the apparatus is A laser device for generating a laser beam, An optical fiber having a distal delivery end for guiding the laser beam to the target tissue, The laser device includes a controller configured to generate multiple laser pulses substantially along the same longitudinal axis, The controller is further configured to cause the laser device to provide the plurality of laser pulses, the plurality of laser pulses being configured by the controller to have sufficient energy to form a plurality of vapor bubbles in the liquid medium at the distal delivery end of the optical fiber, the plurality of vapor bubbles comprising a first vapor bubble and a second vapor bubble formed distal to the first vapor bubble, The apparatus is configured such that, once the first vapor bubble begins to collapse, the controller causes the second vapor bubble among the plurality of vapor bubbles to expand by an amount sufficient to displace a portion of the liquid medium from the space between the delivery end of the optical fiber and the target tissue, the plurality of laser pulses are delivered to the target tissue through the plurality of vapor bubbles, and the time intervals between adjacent pulses of the plurality of laser pulses are non-uniform. (Embodiment 3) The apparatus according to Embodiment 2, wherein the procedure is a prostate enucleation, and the plurality of laser pulses are first configured for mechanical tissue separation, followed by the plurality of laser pulses configured for incising the mechanically separated tissue. (Embodiment 4) The apparatus according to Embodiment 2, wherein the procedure is a lithotripsy for reducing the size of a kidney stone, and the plurality of laser pulses are configured to first induce cavitation that carries the stone in front of the optical fiber, followed by a series of low-energy, high-repetition-rate pulses that result in stone dusting that reduces the size of the kidney stone. (Embodiment 5) The apparatus according to Embodiment 2, wherein the procedure is a prostate enucleation, and the plurality of laser pulses are configured to first perform one or more incisions or ablations of the target tissue, followed by the plurality of laser pulses configured to coagulate the tissue that has been incised or ablated. (Embodiment 6) The tubular hollow choke is further configured to be installed on either the distal end of the optical fiber or the distal end of an endoscope, wherein the endoscope is introduced into the body lumen and the distal end of the optical fiber passes through the endoscope, The apparatus according to Embodiment 2, wherein the choke is configured to shape one or more of the plurality of vapor bubbles formed distal to one of the distal ends of the endoscope or the distal end of the optical fiber when the laser device generates a laser beam. (Embodiment 7) The apparatus according to Embodiment 6, wherein the tubular hollow choke is either cylindrical or tapered truncated cone in shape. (Embodiment 8) The apparatus according to Embodiment 7, wherein the taper is either a tapered shape that widens from the proximal end to the distal end of the frustoconical hollow choke, or a tapered shape that converges.

[0050] (Embodiment 9) Apparatus for laser beam treatment of target tissue, A laser source configured to be connected to an optical fiber configured to be inserted into a body lumen having target tissue surrounded by a liquid medium, The system includes a controller configured to cause the laser source to generate a plurality of laser pulses having sufficient energy to vaporize the liquid medium and form a plurality of vapor bubbles, An apparatus wherein, while the first vapor bubble of the plurality of vapor bubbles collapses, the second vapor bubble of the plurality of vapor bubbles expands, and laser radiation is delivered to the target tissue through the second vapor bubble of the plurality of vapor bubbles, and the second vapor bubble of the plurality of vapor bubbles is formed distal to the first vapor bubble of the plurality of vapor bubbles. (Embodiment 10) The apparatus according to Embodiment 9, wherein the time intervals between adjacent pulses of the plurality of laser pulses are non-uniform. (Embodiment 11) The apparatus according to Embodiment 9, wherein the target tissue is prostate tissue. (Embodiment 12) The apparatus according to Embodiment 9, wherein the target tissue is a calculus. (Embodiment 13) The apparatus according to Embodiment 9, wherein the first vapor bubble of the plurality of vapor bubbles expands to a first diameter, and the second vapor bubble of the plurality of vapor bubbles expands to a second diameter different from the first diameter. (Embodiment 14) The apparatus according to Embodiment 13, wherein the first diameter is smaller than the second diameter. (Embodiment 15) The apparatus according to Embodiment 9, wherein the first vapor bubble of the plurality of vapor bubbles at least partially surrounds the distal end of the optical fiber. (Embodiment 16) The apparatus according to Embodiment 9, wherein the second vapor bubble of the plurality of vapor bubbles is located away from the distal end of the optical fiber. (Embodiment 17) The apparatus according to Embodiment 9, wherein the first vapor bubble of the plurality of vapor bubbles at least partially surrounds the distal end of the optical fiber. (Embodiment 18) The apparatus according to Embodiment 9, wherein the plurality of vapor bubbles include a first vapor bubble and a second vapor bubble, and the formation of the second vapor bubble is initiated during a period in which the diameter of the first vapor bubble is decreasing and the pressure within the first vapor bubble is increasing. (Embodiment 19) A medical system, Laser source and An optical fiber configured to be connected to the laser source, wherein the optical fiber is further configured to be inserted into a body lumen having target tissue surrounded by a liquid medium, The system includes a controller configured to cause the laser source to generate a plurality of laser pulses having sufficient energy to vaporize the liquid medium and form a plurality of vapor bubbles, A system in which, while the first vapor bubble of the plurality of vapor bubbles collapses, the second vapor bubble of the plurality of vapor bubbles expands, and laser radiation is delivered to the target tissue through the second vapor bubble of the plurality of vapor bubbles, and the second vapor bubble of the plurality of vapor bubbles is formed distal to the first vapor bubble of the plurality of vapor bubbles. (Embodiment 20) The system according to Embodiment 19, wherein the time intervals between adjacent pulses of the plurality of laser pulses are non-uniform. (Embodiment 21) The system according to Embodiment 19, wherein the target tissue is prostate tissue. (Embodiment 22) The system according to Embodiment 19, wherein the target tissue is a calculus. (Embodiment 23) The system according to Embodiment 19, wherein the first vapor bubble of the plurality of vapor bubbles expands to a first diameter, and the second vapor bubble of the plurality of vapor bubbles expands to a second diameter different from the first diameter. (Embodiment 24) The system according to Embodiment 23, wherein the first diameter is smaller than the second diameter. (Embodiment 25) The system according to Embodiment 19, wherein the first vapor bubble of the plurality of vapor bubbles at least partially surrounds the distal end of the optical fiber. (Embodiment 26) The system according to Embodiment 19, wherein the second vapor bubble of the plurality of vapor bubbles is located away from the distal end of the optical fiber. (Embodiment 27) The system according to Embodiment 19, wherein the first vapor bubble of the plurality of vapor bubbles at least partially surrounds the distal end of the optical fiber. (Embodiment 28) The system according to Embodiment 19, wherein the plurality of vapor bubbles include a first vapor bubble and a second vapor bubble, and the formation of the second vapor bubble is initiated during a period in which the diameter of the first vapor bubble is decreasing and the pressure within the first vapor bubble is increasing.

Claims

1. A device for treating a target with a laser beam, A laser source configured to be connected to an optical fiber configured to be inserted into a body lumen containing a liquid medium, The system includes a controller connected to the laser source and configured to generate a first periodic pulse train packet, a second periodic pulse train packet, and a third periodic pulse train packet in the laser source, The first periodic pulse train packet comprises a first plurality of pulses, At least one of the first plurality of pulses has different pulse parameters from another pulse of the first plurality of pulses. The second periodic pulse train packet comprises a second plurality of pulses, The third periodic pulse train packet comprises a third plurality of pulses, The delay between adjacent pairs of the first plurality of pulses is different from the delay between adjacent pairs of the second plurality of pulses, and / or An apparatus in which the delay between the first plurality of pulses of the first periodic pulse train packet and the second plurality of pulses of the second periodic pulse train packet is different from the delay between the second plurality of pulses of the second periodic pulse train packet and the third plurality of pulses of the third periodic pulse train packet.

2. The apparatus according to claim 1, wherein the pulse parameter is pulse energy, energy distribution between adjacent pulses, or time interval between adjacent pulses.

3. The apparatus according to claim 1 or 2, wherein the delay between adjacent pulses of the plurality of pulses is the same.

4. The apparatus according to claim 1 or 2, wherein the delay between one adjacent pair of the plurality of pulses is different from the delay between another adjacent pair of the plurality of pulses.

5. The apparatus according to any one of claims 1 to 4, wherein at least one pulse of the second plurality of pulses has different pulse parameters from another pulse of the second plurality of pulses.

6. The apparatus according to any one of claims 1 to 4, wherein at least one pulse of the first plurality of pulses has different pulse parameters from at least one pulse of the second plurality of pulses.

7. The apparatus according to any one of claims 1 to 4, wherein the first plurality of pulses have a different number or number of pulses from the second plurality of pulses.

8. A device for treating a target with a laser beam, A laser source configured to be connected to an optical fiber configured to be inserted into a body lumen containing a liquid medium, The system includes a controller connected to the laser source and configured to generate periodic pulse train packets in the laser source, The aforementioned periodic pulse train packet comprises multiple pulses, At least one of the plurality of pulses has different pulse parameters from another of the plurality of pulses. The device wherein the pulse parameters are selected based on the distance between the distal end of the optical fiber and the target.

9. The apparatus according to claim 8, wherein the pulse parameter is pulse energy, energy distribution between adjacent pulses, or time interval between adjacent pulses.

10. Is the delay between adjacent pulses of the aforementioned plurality of pulses the same? The apparatus according to claim 8 or 9, wherein the delay between one adjacent pair of the plurality of pulses is different from the delay between another adjacent pair of the plurality of pulses.

11. The aforementioned periodic pulse train packet is a first periodic pulse train packet, and the aforementioned plurality of pulses are the first plurality of pulses. The apparatus according to claim 10, wherein the controller is further configured to cause the laser source to generate a second periodic pulse train packet having a second plurality of pulses.

12. The apparatus according to claim 11, wherein the controller is further configured to cause the laser source to generate a third periodic pulse train packet having a third plurality of pulses.

13. The apparatus according to claim 12, wherein the delay between the first periodic pulse train packet and the second periodic pulse train packet is different from the delay between the second periodic pulse train packet and the third periodic pulse train packet.

14. The apparatus according to any one of claims 11 to 13, wherein at least one pulse of the second plurality of pulses has different pulse parameters from another pulse of the second plurality of pulses, and / or, at least one pulse of the first plurality of pulses has different pulse parameters from at least one pulse of the second plurality of pulses.

15. The apparatus according to any one of claims 11 to 13, wherein the delay between adjacent pulses of the first plurality of pulses is the same, or the delay between adjacent pulses of the second plurality of pulses is the same, or the delay between adjacent pulses of the first plurality of pulses and the delay between adjacent pulses of the second plurality of pulses are the same.

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