System for monitoring temperature during internal laser lithotripsy

Abstract

To provide a system for monitoring temperature during laser beam-based lithotripsy.SOLUTION: A system includes a module part 9. The module part includes: a flow rate sensor 10 which is attachable side by side with an irrigation fluid channel and determines an irrigation fluid quantity without contacting the irrigation fluid; input means 13 which is connected to a processing part 12 and is capable of transmitting to the processing part an operation parameter of laser to become a basis for determining laser output that can be irradiated to a position of a light emission port 4; a temperature sensor 11 which is attachable side by side with the irrigation fluid channel and determines temperature of the irrigation fluid without contacting the irrigation fluid; an analysis part 14 which is fitted to the processing part and numerically determines temperature T generated in the body during laser lithotripsy at a position of the light emission port on the basis of at least the irrigation fluid quantity, temperature (TS) of the irrigation fluid, and the determined irradiation laser output; and a comparison part 15 which compares the determined temperature T with threshold and generates a signal when the temperature is over the threshold.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a system for monitoring temperature during the performance of laser light-based lithotripsy that employs an endoscopic assembly comprising an actuation channel for an optical fiber cable optically connected to a laser on the proximal side and having a light exit port on the distal side, and an irrigation fluid channel that opens into the region of the light exit port on the distal side and is in fluid connection with an irrigation fluid reservoir on the proximal side.

Background Art

[0002] Lithotripsy is a minimally invasive surgery for crushing stones such as gallstones, urinary tract stones, or kidney stones. Stones mainly aggregate in the excretory ducts of the affected organs and can cause severe pain as well as other medical problems. Among many known in vivo lithotripsy treatments, laser-induced lithotripsy has become an established treatment method. In this treatment, a high-energy laser beam is irradiated in the form of laser pulses through an optical fiber cable to the position of the stone to be crushed. When the laser pulses interact with the medium in the body, vapor bubbles are formed. These pulsed expansions generate pressure waves, which cause the fragmentation of the stone. Depending on their size, the fragments of the stone created by laser-induced lithotripsy can be excreted naturally or extracted with a properly configured endoscopic grasping tool.

[0003] Endoscopes are used to perform laser light-based lithotripsy. The endoscope has at least one actuation channel for an optical fiber cable that is optically connected to a laser on the proximal side and has a light exit port on the distal side. To enable following the access path to the stone within the endoscope and to minimize the burden on the patient during the procedure, this type of endoscope may have a flexible and bendable configuration. In addition, irrigation fluid can be applied through an actuation channel that, in many cases, opens into the region of the light exit port on the distal side and is in fluid connection with an irrigation fluid supply device and an irrigation fluid reservoir in the form of an irrigation syringe and / or a controllable or adjustable supply pump on the proximal side.

[0004] Using this type of endoscope assembly equipped with an endoscope and the aforementioned peripheral equipment connected thereto, the laser output irradiated inside the body at the position of the stone to be crushed and the amount of the perfusion fluid discharged into the distal perfusion channel need to be coordinated with each other so that, on the one hand, effective stone crushing can be performed and, on the other hand, local overheating of the peripheral area of the tissue by the laser light (which may cause irreversible damage to the tissue) does not occur. In most cases, this type of endoscope is provided with an additional glass fiber optical system or an image sensor for the operator at the tip of the endoscope. The tip of the endoscope must be optically cleared using a metered delivery of the perfusion fluid to ensure a clear field of view for the operator for monitoring the crushing process.

[0005] Patent Document 1 describes this type of endoscope assembly for performing laser light-based lithotripsy, which has a related perfusion fluid supply unit that can be adjusted according to at least one of the parameters affecting the stone crushing process, that is, the perfusion flow rate is affected by the stone crushing process. In addition to the optical monitoring of the stone crushing process, a known endoscope assembly is provided with a temperature sensor attached to the tip of the endoscope that can detect the distal temperature of the fluid surrounding it, and the perfusion fluid supply unit is restricted based on this to adjust the flow rate of the perfusion fluid.

[0006] Even in the case of a known medical endoscope according to Patent Document 2, which is suitable for performing laser light-based lithotripsy, a peripheral temperature sensor is provided in the distal region of the endoscope for the purpose of temperature measurement.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0008] An endoscope assembly equipped with such sensors constitutes an extremely complex medical device that must undergo comprehensive medical-technical approvals and tests over a long period of time.

Means for Solving the Problems

[0009] The object of the present invention is to be able to perform intracorporeal lithotripsy monitored with this type of standard endoscope without the need for excessive cost and time for medical-technical inspections or approvals. It is optically connected to a laser on the proximal side and has an operating channel for an optical fiber cable with a light exit port on the distal side, and a perfusion fluid channel that opens to the region of the light exit port on the distal side and is fluidly connected to a perfusion fluid reservoir on the proximal side. By further developing a system for monitoring temperature during the performance of laser light-based lithotripsy that employs an endoscope assembly, in order to be able to exclude any thermally induced tissue degradation that may occur in the area immediately surrounding the stone fragmentation site, by that means, components appropriately selected for other already used medical-technical devices such as endoscopes, laser systems, and perfusion fluid devices for passive and active perfusion generally suitable for laser light-based lithotripsy are required to be retrofittable.

[0010] The solution to the basic object of the present invention is defined in claim 1. The features that further develop the inventive concept in an advantageous manner are formed by the subject matter of the dependent claims and further explanations, in particular, with reference to the exemplary embodiments.

[0011] Generally, the application of an in vivo laser without irrigation, i.e., without the supply of irrigation fluid to the area of the distal light exit port of the optical fiber cable, is only possible for a short time, i.e., less than a few seconds, and in the absence of the cooling provided by irrigation as well, the critical temperature of about 42°C is reached and exceeded, beyond which the surrounding tissue will be irreversibly thermally damaged. As a result, irrigation during laser light-based lithotripsy is essential to ensure sufficient cooling.

[0012] The exact numerical or theoretical relationship between the laser output irradiated in the body, the flow rate of the irrigation fluid, the temperature of the irrigation fluid, and the temperature in the body occurring during the application of laser pulses is known from a number of experiments on laser light-based lithotripsy performed so far.

[0013] Based on this finding, in the case of a known endoscope having at least one working channel for an optical fiber cable optically connected to the laser on the proximal side and having a light exit port on the distal side, and an irrigation channel that may be separate or integral with the working channel, opening into the area of the light exit port on the distal side and fluidly connected to an optional irrigation fluid supply on the proximal side and an irrigation fluid reservoir, it is possible to combine it with a module unit comprising at least one flow sensor and at least one temperature sensor that are each detachably and fixedly attachable in line with the irrigation channel and / or the supply line fluidly connected to the irrigation channel in the extracorporeal region of the endoscope assembly. In this way, the flow sensor is configured and arranged such that the irrigation flow rate can be determined without contact with the irrigation fluid. At the same time, the temperature sensor is configured and attached in line with the irrigation channel and / or the supply line fluidly connected to the irrigation channel such that the temperature of the irrigation fluid can be determined without contact.

[0014] Furthermore, the module unit includes either input means through which operating parameters for the laser can be input and which can transmit the operating parameters for the laser to a processing unit connected to the input means, or an interface through which the operating parameters for the laser can be directly transferred. The operating parameters for the laser preferably include the laser output, whereby the calculation of the laser output irradiated at the position of the light exit port can be calculated via the laser pulse frequency and the individual pulse energy.

[0015] In addition, an analysis unit that numerically determines the temperature generated in the body during laser light-based lithotripsy at the position of the light exit port is attached to the processing unit based on the perfusion flow rate obtained by the sensor of the perfusion fluid, the temperature obtained by the sensor, and the determined laser output applied in the body. The comparison unit is separated from or integrated with the processing unit, and for example, compares an adjustable threshold value of 42°C with the determined temperature and generates a signal when the threshold value is exceeded.

[0016] In addition, in a preferred embodiment, a signal unit connected to the comparison unit by wireless or wiring is provided, whereby the signal generated by the comparison unit can be made perceptible tactilely, audibly, and / or visually. By means of the signal unit, the doctor performing the lithotripsy can be aware of the influence of potential overheating in the body and can interrupt the lithotripsy treatment or take other means.

[0017] The module unit according to the present invention, which is preferably configured as a retrofit set or a retrofit kit, exclusively includes components that can be modularly attached to an endoscope assembly already in use without impairing the general functions of the endoscope assembly. Thus, the system according to the present invention constitutes a safety system that supports a doctor during the performance of laser light-based lithotripsy, thereby enabling the doctor to receive reliable information that allows the lithotripsy treatment to be performed effectively and in a patient-friendly manner.

[0018] The information necessary in this regard is merely the current temperature of the irrigation fluid in the body introduced through the operating channel or the irrigation fluid channel via the endoscope assembly, the laser output irradiated at the position of the stone to be fragmented, and the irrigation flow rate of the irrigation fluid introduced into the body through the operating channel or the irrigation fluid channel at the position where the laser light is applied.

[0019] The sensors required for the irrigation fluid temperature and the irrigation flow rate respectively constitute structural elements that are detachably and fixedly attached to the irrigation fluid channel and / or the supply line fluidly connected to the irrigation fluid channel in the region of the endoscope assembly that is not introduced into the body towards the body. Thus, preferably, the sensor for determining the irrigation flow rate is a flow sensor in the form of an ultrasonic sensor. A temperature sensor in the form of an infrared sensor seems appropriate for obtaining the temperature of the irrigation fluid.

[0020] The operating parameters that can be specified for the laser necessary for determining the temperature generated at the light exit port of the optical fiber cable are the laser pulse frequency and the individual pulse energy. These operating parameters can be supplied by appropriately configured input means such as a keyboard, voice-operated input means, or a direct interface of the processing unit with the laser device.

[0021] The analysis unit attached to the computer unit determines the temperature T generated at the light exit port based on the following mathematical formula as follows.

Equation

[0022] The numerical relationship between the temperature generated in the body during laser light-based lithotripsy at the position where the laser light is applied, the irradiated laser output, the irrigation flow rate, and the temperature of the irrigation fluid has been confirmed in a number of in vitro and ex vivo experiments.

[0023] Even if the above algorithm shows a simple and stereotypical relationship, the expected final temperature in the body at the position of stone fragmentation during laser-based lithotripsy can be predicted accurately enough by the above algorithm, and local overheating that may cause irreversible tissue damage in the immediate vicinity of the position of laser-based lithotripsy can be eliminated.

[0024] When the laser unit does not have an interface for indicating the laser operation, the module unit further includes a microphone unit for detecting an acoustic signal indicating the operation of the laser, which is transmitted to an analysis unit for the purpose of signal analysis synchronized with the actual laser operation. In this way, during the operation of the laser, the laser produces a clearly detectable acoustic signal that can be detected by the microphone unit in a time-resolved manner.

[0025] When performing laser-based lithotripsy, the doctor responsible for performing the lithotripsy is the sole decision maker. However, in a further embodiment, the module unit according to the present invention includes an additional emergency stop switch, that is, in addition to the audible, visual, and / or tactile signal transmission signal unit, and can also cause at least the power supply of the laser source to be cut off by a signal.

[0026] In a further preferred embodiment, the modular part that can be adapted to the endoscope assembly separately has a unit for detecting the filling level of the amount of the perfusion fluid contained in the perfusion fluid reservoir. The unit is in the form of a software-based analysis algorithm implemented in a processing unit that determines the current filling level based on a sensor provided in the perfusion fluid reservoir and / or the perfusion flow rate detected by the sensor and the measured period during which the release of the perfusion fluid occurred. The sensor signal representing the filling level or the numerically determined filling level value representing the filling level functions at least to monitor the actual state, to predict the time required until the perfusion fluid reservoir is completely emptied, or as a warning when the minimum remaining amount is reached. The information thus obtained is made optically or aurally recognizable to the doctor by appropriate display. The display may be made by a signal part that warns the doctor performing the lithotripsy of the possible influence of overheating in the body through it or by an additional display.

[0027] A further embodiment enables additional monitoring of the temperature of the supplied perfusion fluid. For this purpose, the temperature (T S ) of the perfusion fluid detected by the sensor is preferably displayed as an alphanumeric value on a visual display unit. Further, the measured temperature is preferably supplied to a comparison unit or a further comparison unit, where a signal is generated that functions to warn the doctor performing the treatment when the temperature (T S ) of the perfusion fluid exceeds or falls below a critical temperature value. As an example, when the perfusion fluid is too cold, a warning is issued to avoid the risk of the patient developing hypothermia.

[0028] In a further possible embodiment, the perfusion fluid supply part is provided with means capable of adjusting the flow rate of the perfusion fluid according to the temperature T generated at the position of the light emission port and / or according to at least one operating parameter of the laser. Thereby, it becomes possible to actively adjust the amount of the perfusion fluid to the perfusion fluid supply part in the form of a pump according to the irradiated laser light output and / or the temperature calculated in the intervention area.

[0029] The system according to the present invention for monitoring temperature during laser-based lithotripsy can be used in various anatomical regions such as the bladder, ureter, or renal pelvis region. Depending on the application region, different modes suitable for the intervention may be selected. In this regard, the system provides a selection of prostate, bladder, ureter, or renal pelvis modes that are distinguished by definable warning limits and stored characteristics. In this way, the individual risk spectra for various surgeries can be addressed.

[0030] Thus, the system can be used in any laser-based procedure in the urological field, particularly laser lithotripsy, prostatectomy (HoLEP, ThuLEP), laser vaporization (PVP), and interstitial laser coagulation (ILC).

Brief Description of the Drawings

[0031]

Figure 1

Embodiments for Carrying Out the Invention

[0032] One drawing shows an endoscope 1 having an operating channel for an optical fiber cable 2 that is optically connected to a laser 3 on the proximal side and has a light exit port 4 on the distal side. Further, the endoscope 1 has an irrigation fluid channel 5 that opens into the region of the light exit port 4 on the distal side and is fluidly connected to a fluid supply 6 and a fluid reservoir 7 on the proximal side. Obviously, an endoscope that combines the irrigation fluid channel 5 and the operating channel for the optical fiber cable 2 into one channel is also known. This type of known endoscope assembly functions to break up a body stone 8 during the process of laser-based lithotripsy.

[0033] The system according to the present invention for monitoring temperature relates to a module unit 9 that can be combined with the extracorporeal region of an endoscope assembly including the endoscope 1, the laser 3, the fluid supply 6, and the fluid reservoir 7. In a preferred embodiment, it comprises the following components.

[0034] Along the perfusion fluid supply line 5, a flow rate sensor 10, preferably in the form of an ultrasonic sensor, is detachably fixed. Similarly, along the perfusion fluid channel 5 or the supply line fluidly connected thereto, a temperature sensor 11 for detecting the temperature of the perfusion fluid, preferably in the form of an infrared sensor, is detachably fixed. The sensor signals S, T generated by the sensors 10, 11 S are transmitted to the processing unit 12 by wireless or wired connection.

[0035] Furthermore, input means 13 is provided, preferably in the form of an interface to a laser unit for automatic operation parameter transmission or alternatively in the form of a manually operable keyboard through which the operation parameters for the laser 3 can be input. For the operation of the laser 3, the laser pulse frequency f L and the individual pulse energy E P can be specified by the operator. These operation parameters can also be supplied to the processing unit 12 via the input means 13, and based on this, the laser output that can be applied to the position of the light emission port 4 can be calculated.

[0036] The analysis unit 14 is installed in the processing unit 12 and determines the current temperature generated at the position of the light emission port 4 based on the operation parameters of the laser, the perfusion flow rate S of the perfusion fluid detected by the sensor, and the temperature T S according to the following algorithm.

Equation

[0037] Next, the determined body temperature T is compared in the comparator 15 with an adjustable threshold value where preferably T K = 42 °C. If the threshold value T K is exceeded, the comparator 15 generates a signal S K which is then perceptible tactilely, audibly and / or visually by the physician performing the lithotripsy.

[0038] In addition, the microphone unit 17 is connected to the processing unit 12, and thereby the operation of the laser 3 is detected. As a result, synchronization with the actual operation of the laser 3 is realized by the processing unit 12 and the data processed by the analysis unit 14 implemented therein and the signal S K generated therefrom.

Explanation of Signs

[0039] 1 Endoscope 2 Optical fiber cable 3 Laser 4 Light emission port 5 Irrigation fluid 6 Irrigation fluid supply unit 7 Irrigation fluid reservoir 8 Stone 9 Module unit 10 Flow sensor 11 Temperature sensor 12 Processing unit 13 Input means 14 Analysis unit 15 Comparison unit 16 Signal unit 17 Microphone unit

Claims

[Claim 1] 1. A system for monitoring temperature during a laser light based lithotripsy procedure employing an endoscope assembly including a working channel for a fiber optic cable optically connected to a laser at a proximal side and having a light exit at a distal side, and an irrigation fluid channel opening at said distal side into the region of said light exit and in fluid communication with an irrigation fluid reservoir at said proximal side, a modular portion that can be combined with the endoscope assembly; The module portion includes: a flow sensor mountable alongside the irrigation fluid channel and / or a supply line in fluid communication with the irrigation fluid channel to determine an irrigation flow rate without contacting the irrigation fluid; an input means connected to a processing unit and capable of transmitting to said processing unit operating parameters for said laser that are the basis for determining a laser output that can be irradiated at the position of said light exit opening; a temperature sensor mountable alongside the irrigation fluid channel and / or a supply line in fluid communication with the irrigation fluid channel, the temperature sensor being non-contact with the irrigation fluid to determine a temperature of the irrigation fluid; A device is attached to the processing unit, and a device for controlling at least the irrigation flow rate and the temperature of the irrigation liquid (T Ｓ an analysis unit that numerically determines a temperature T generated in the body during the laser light-based lithotripsy at the position of the light exit port based on the determined irradiation laser power; a comparator for comparing the determined temperature T with a threshold and generating a signal if the determined temperature T exceeds the threshold; A system comprising:

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