Insufflation system and method for synchronising two insufflators in laparoscopy, in particular in transanal total mesorectal excision

Abstract

The invention relates to a system for insufflation, in particular in a transanal total mesorectal excision (taTME), comprising two identically designed insufflators, of which the sensor system and mode of operation are synchronised with one another to such an extent that they optimally assist with the procedure. The two insufflators, which initially insufflate (expand) different cavities in the abdominal cavity, are coordinated according to the invention in relation to their target values and operating states.

Description

[0001] Insufflation system and method for synchronizing two insufflators in laparoscopy, particularly in transanal total mesorectal excision

[0002] Subject of the invention

[0003] The invention relates to an insufflation system, particularly for transanal total mesorectal excision (taTME), comprising two identical insufflators whose sensors and operating modes are coordinated to optimally support the procedure. The two insufflators, which initially insufflate (expand) different cavities in the abdominal cavity, are coordinated according to the invention with regard to their setpoints and operating states.

[0004] State of the art

[0005] TAMIS is a transanal minimally invasive surgical procedure with the goal of local excision, total mesorectal excision (TME), or the removal of foreign bodies. The insufflated cavity is only the rectum or colon. taTME is a special TAMIS procedure with the goal of TME. The insufflated cavity is the closed rectal segment and a pelvic wound cavity that subsequently developed after the excision, as well as the abdominal cavity (abdomen, laparoscopy).

[0006] When insufflating two adjacent cavities, pressure fluctuations occur due to pressure control and leaks, causing the cavity wall (border between the two cavities) to move, making it difficult for the surgeon to suture. If the insufflator provides this capability, a taTME mode is used for the smaller cavity in the rectum. This mode is characterized by a design for small cavities with adapted (faster) time constants and (smaller) manipulated variable changes. If the insufflator does not provide this mode, an alternative control similar to that used for other small cavities, e.g., a pediatric mode (baby / toddler mode), is used.

[0007] Controlling the transanal side, with a volume typically ranging from several tens to hundreds of milliliters, is critical. Later in the procedure, an incision is made in the intestinal wall, expanding the cavity to several liters. A system typically consisting of two identical types of insufflators is used to expand both body cavities. One insufflator is used for the laparoscopic portion, the other for the transanal portion. Here, the insufflators are typically set to the same target pressure.

[0008] According to the state of the art, such a system from the manufacturer Karl Storz allows device communication via the HIVE standard from a central control unit. Menu selection for the insufflators in the central system is done by finding "TME" as a menu item, which is a submode of "TEO." This preselects the insufflators for this mode.

[0009] The devices use existing control systems for the cavity pressure, which is usually measured using a sensor in the device. This makes it necessary to either feed the pressure to this sensor via a fluidic connection or to pause the inflow to record the cavity pressure via the inflow line through pressure equalization. If no measurement pause is taken, the back pressure through the introduction is measured, which is increased by, among other things, the flow resistance of the supply line. Either a "pediatric mode" is used for control, which operates discontinuously and uses measurement pauses to determine the cavity pressure, or a "taTME mode" which insufflates continuously. In the "taTME mode", pressure estimators that are already state of the art are used for control.

[0010] The medical procedure for taTME involves laparoscopic dissection and subsequent rectal mobilization, with the insufflator then continuing to work in the residual rectal cavity. After laparoscopic dilation, the transanal access is established. A purse-string suture (with mechanical expansion) is then used to close the lumen. A gel port is then inserted to protect the biological structures from the instruments and create a seal. The cavity is then insufflated minimally invasively.

[0011] This results in technical problems regarding the stability of the control system, initially during the expansion of the smaller cavity next to a larger cavity connected by a membrane (bowel wall), which is also pressure-controlled, until the wall is severed. If the bowel wall is then opened, i.e., the two cavities are connected, this presents another technically challenging situation, which has so far only been managed through user intervention (changing the target pressure or temporarily switching off an insufflator).

[0012] The next medical procedure involves freeing and removing the portion of the rectum from the dilated abdominal cavity. Immediately afterward, with taTME, the mobilized rectum is withdrawn from the body, leaving only one dilated (abdominal) cavity. With the rectum removal, the connections of the second insufflator (used in the intestine) are also removed. All walls are then medically resealed.

[0013] The typical target pressure for laparoscopic insufflators is 12 mmHg. For the transanal portion, the medically preferred Airseal® insufflator is a CONMED Airseal® insufflator, which has a target pressure of 15 mmHg. Airseal® insufflators replace the instrument shaft seal with a fluidized bed of gas, and the pressure profiles in the control system are more "compliant," allowing extremely constant pressure regulation. Such stable regulation often does not work with standard insufflators. According to surgical experts, the advantage of Airseal® technology is that there is no pulsation of the small cavity, but suction is poor because smoke is drawn directly past the optics and condenses there. Volume enlargement using an Insufflation Stabilization Bag (ISB) from Applied Medical is sometimes used, or support is sought with another smoke evacuation device.Overall, the insufflation of the residual rectal cavity is technically unsatisfactory.

[0014] The use of high-frequency electrotomes and other thermally based cutting modalities requires smoke evacuation to maintain visibility of the surgical site. This is already known in the art and utilizes a circulating, filtered gas purge.

[0015] The technical issues to be resolved arise when the surgeon switches between laparoscopic and transanal techniques – what does the laparoscopic insufflator do when working transanally? Should one of the pressures be reduced? When should transanal insufflation be activated and when should it be deactivated (e.g., for a measurement break)?

[0016] The solution according to the invention relates to certain subfunctions of an insufflator system, which otherwise, according to the prior art, has a pressure control with refilling of the expansion medium to compensate for leakage and optionally a function for smoke gas removal.

[0017] In similar application scenarios, determining the leak tightness of surgically prepared hollow organs is protected in W02020 / 021520A1 "Leak detecting apparatus, and a method for detecting a leak in a hollow organ or lumen in a human or animal body." This solution differs significantly in the requirement of stability of the set pressure, and both pressure regulators and all sensors are controlled in one device, i.e., all information about both cavities is always directly comparable (see Figs. 1-4, both pressure regulators are controlled by a microprocessor (50)). In the problem according to the invention, communication between independently operating, separate devices is precisely what is required.

[0018] Inventive solution

[0019] The above-mentioned problem is solved by the inventive provision of a system for insufflation during a transanal total mesorectal excision (taTME) with two identical insufflators, whose sensor technology and mode of operation are coordinated to optimally support the procedure. Such a system is defined in claim 1, and further embodiments are described in the subclaims.

[0020] The situation required a multi-variable control system with 4 control variables: Inflow (supply) to cavity 1 qinsl , Outflow (active suction, or identically possible for the invention: passive discharge) from cavity 1 q S ud , inflow to cavity 2 qins2 and outflow from cavity 2 q Suc2, as well as two controlled variables: pressure in cavity 1 = pc1 and pressure in cavity 2 = pc2 (see Fig. 1). The inventive solution is therefore a control system that spans multiple devices or is distributed but coordinated across two devices. The control objective is to keep the pressure stable, which requires a high level of control accuracy, as otherwise the execution of medical procedures would be difficult. Stable pressure in the cavity is essential for clean incisions or preparations by the surgeon, as well as for suturing. The size ratios of the cavities can vary from several liters for the larger cavity to 50 mL for the smaller cavity.

[0021] The system for the larger cavity must react slowly so that a disturbance in the smaller cavity does not affect the control of the larger cavity. To do this, the system must recognize that it is insufflating a larger cavity in such a proximity. This can be achieved with a known mode (e.g., a 'taTME' mode is selected on the device by the user) by determining the size of the insufflated cavity according to the state of the art (DE 10 2020 003 419 A1, WO 2021 / 244690 A1), leading to an assignment in the device to the smaller or larger cavity.

[0022] A first essential feature of the invention is therefore the comparison of the cavity sizes. Each system determines the cavity size independently using a suitable method, e.g., as described in WO 2021 / 244690 A1. The pressure is measured while the cavity is filled with fluid. By introducing the fluid volume into the cavity, the pressure in this cavity increases. This causes the cavity to expand, thus enlarging the field of view or the surgical field.

[0023] The so-called compliance (extensibility) of a cavity C c can be determined using the relationship between introduced volume V c and thus resulting pressure p c , as a static characteristic curve using the

[0024] Equation C c =V c / p c be determined (see WO 2021 / 244690 A1 , Fig. 1a).

[0025] The inverse of compliance C c is called elasticity E c = 1 / Cc , designated.

[0026] The two determined cavity sizes are then compared. The insufflator that determined the smaller cavity (50-150 mL) is assigned as connected to the rectum (rectal insufflation), while the insufflator that determined the larger cavity (>300 mL) is assigned as connected to the abdomen (abdominal insufflation). In the case of interference with discontinuous insufflation, i.e., insufflation with measurement pauses during which the cavity pressure is transmitted via the insufflation line and measured in the device, it is advantageous for both insufflators to have their measurement pauses different from each other. Here, too, the device must detect a measurement pause from another insufflator connected via a membrane, or rather, not interpret this disturbance as a pressure fluctuation.Typically, measurement pauses depend on the tubing length and viscosity of the insufflation medium to allow pressure equalization between the cavity and the sensor location. For taTME, these pauses are approximately 0.1 to 0.5 seconds and are inserted at intervals of at least every 2.5 to 3 seconds. The measurement pauses can be extended with slow control without significantly affecting the stability of the control. The frequency of the measurement pauses is relatively freely selectable and depends on leaks, for example, due to frequent instrument changes or similar scenarios. This data is collected from observations of medical procedures.

[0027] A similar problem exists analogously in the area of ​​electrical power supplies for charging an energy storage device. Here, too, two power supplies used as charging systems on an energy storage device do not know each other: The solution chosen there according to the state of the art is to synchronize the sensors (both measure identically) or to charge asynchronously.

[0028] A second essential feature of the invention is therefore the comparison of the measurement pauses. Each system independently determines the rhythm of the measurement pauses by observing the pressure in the insufflated cavity when the inflow is stopped. For example, if the rectally insufflated system detects a regular pressure fluctuation or a pressure drop of (5 mmHg) every 3 seconds, with the duration of the pressure drop lasting a maximum of one second, the system assumes that the abdominally insufflated system has a measurement interval of 3 seconds.

[0029] If, for example, the abdominal insufflation system detects a regular pressure drop of (5 mmHg) every 1.8 seconds, with the duration of the pressure drop being a maximum of one second, then the system assumes that the rectal insufflation system has a measuring interval of 1.8 seconds. A further aspect of the solution according to the invention occurs when the cavities are united, i.e. when the surgeon perforates the membrane between the cavities. In one embodiment of the invention, suction can be carried out via the insufflator of the larger cavity in accordance with pressure regulation of the larger cavity or only as a safety venting when a warning limit is exceeded, while the supply is stopped. In this case, the insufflator of the smaller cavity interrupts suction and regulates the pressure of the smaller cavity via the supply, which de facto influences both cavities via just one supply.

[0030] A third essential feature of the invention is therefore the detection of the merging of the cavities and the subsequent change in insufflation. Merging of the cavities can be detected by the measured pressures in the two formerly separate cavities moving toward each other. Typically, the rectal pressure is set approximately 3-5 mmHg higher than the abdominal pressure. A sudden drop in pressure to the level of the abdominal pressure allows the breakthrough of the rectal insufflation system to be detected. After the breakthrough, the rectally insufflating insufflator can discontinue insufflation. Insufflation and, if necessary, suction (venting) can be fully realized via the abdominally insufflating insufflator. The originally rectally insufflating system can be used to measure the pressure of the merged cavity.In cases of significantly increased insufflation requirements, the rectal insufflation system can contribute to insufflation. However, this is likely only relevant in extreme cases (e.g., sudden large leaks).

[0031] In an alternative embodiment, the measurement pauses can be stopped in the smaller cavity and the control can be set to a fixed pressure setpoint pc2, whereby the pressure setpoint pc2 is higher than the pressure setpoint pc1 of the control of the larger cavity. This higher pressure setpoint pc2 can, for example, be up to 20 mmHg, which is above a safety threshold of typically 15 mmHg for insufflation. This safety threshold is no longer relevant for the partial rectal cavity to be excised, and no such pressure buildup occurs in the smaller cavity via the leak (membrane perforation) into the other cavity. In the alternative solution according to the invention, the leaks in the larger cavity are compensated for in the small cavity via the continuous or quasi-continuous supply, while the pressure is controlled via supply and suction in the larger cavity.As long as the insufflator of the smaller cavity does not reject the control parameters determined from the previous situation, this situation is easily manageable. If it does reject the control parameters, the design of the insufflators used for these applications must ensure that the volumes of inflation medium delivered by both insufflators can be handled via a single suction without causing pressure to build up in the cavities. Accordingly, appropriately low outflow resistances must be provided. The outflow branches must therefore be larger than those for a single inflow branch.

[0032] As a technical solution, the systems can recognize the respective situations via their own sensors - provided the context information that a second insufflator is active and connected via a membrane has been given. This can be achieved by the user selecting the appropriate 'taTME' mode or by signal analysis. One task of the sensors can be to switch the control to a control algorithm for the entire cavity with two devices after the intestinal wall has been opened, i.e., the two cavities are connected. Another solution would be to establish a master-slave assignment after detecting the cavity enlargement due to the incision through the intestinal wall. In this case, after the intestinal wall has been opened, i.e., the two cavities are joined, the device can switch to a subordinate mode based on signal analysis of the time-discrete or continuous pressure values ​​measured on the device.

[0033] Another solution is to select a higher target pressure (pc2) transanally, for example, <5 mmHg higher. The goal here would be to avoid turning off one insufflator (for safety reasons). If both are at different pressure settings, one insufflator will not insufflate, while the other insufflator will go into venting (releasing excess pressure). The result is that one insufflator can insufflate passively while the other insufflator ensures smoke evacuation.

[0034] If overall leakage is high, the other insufflator can provide support, serving as a second source of inflation fluid. Counter-rotating measurement pauses on both insufflators can be used to allow gas movement or reduce pressure peaks / ripple.

[0035] The system according to the invention consists of two systems (insufflators in the operating room setting) and has a technological basis with either sensors with selection rules, or a physical communication option and semantic aspects, ie what information needs to be exchanged for the function.

[0036] The embodiment of the invention is further explained below:

[0037] For the medical procedure, two devices with controls based on this invention are used on the patient. Today, surgeons typically use two insufflators of the same type.

[0038] A) Detection of the situation where two insufflators insufflate adjacent cavities

[0039] In addition to the obvious solution of obtaining this information through user input into the relevant device via the operating interfaces or the corresponding operating software, such a situation can be identified by analyzing the insufflator's pressure values ​​over time. As an alternative to the insufflator's measurement pause, only breathing or mechanical ventilation can produce regular changes in the pressure curves. All pressure influences during medical procedures caused by movement or instrument changes are rather stochastic. If, therefore, a brief drop in the pressure values ​​for 0.1 to 0.5 seconds is detected at regular intervals in the pressure curve, and this occurs between three and 20 times in succession at similarly short time intervals between 0.5 and 3 seconds, it can be assumed that two insufflators are being operated that are coupled via a pressure-slack membrane.To improve accuracy, the operating mode LAP for laparoscopic procedures or PÄDI / taTME for insufflation of small-volume cavities, preselected by user input, is required as an additional condition. This can be achieved using sensors that measure discretely or continuously based on state-of-the-art signal analysis of the pressure values.

[0040] In a second alternative embodiment, according to the automatic

[0041] For cavity detection, the size can be determined by observing pressure and inflow through compliance. This is already state of the art and is disclosed in DE 102020 003 419 A1 and WO 2021 / 244690 A1.

[0042] B) Detection of the union of the cavities

[0043] The connection of both cavities is detected by the pressure dropping to a new, stable level without inflow or suction of insufflation medium. In an alternative scenario, the sudden increase in pressure to a new, stable level can occur over a longer period of time without inflow or suction of insufflation medium. In both cases, a longer period of time is defined as exceeding the surgeon's influences (manipulation of the abdominal cavity) that occur during medical procedures, which for taTME is between 5 and 30 seconds. For other medical procedures involving the connection of two cavities, other values ​​must be determined and specified according to the invention.

[0044] In an alternative embodiment, the compliance of the smaller cavity can be determined periodically by determining the flow and pressure values ​​and continuously monitored. If these values ​​change, the smaller cavity has been opened, and the control can be adjusted as in the previous case.

[0045] C) Detection of the insufflator’s assignment to the larger or smaller cavity

[0046] The compliance values ​​(i.e., the division of flow (delta V) by the pressure change (delta p)) are known in advance for smaller intestinal segments and differ from those of the larger abdominal cavity. Since the target pressure is far from the burst limit, the values ​​are relatively easy to determine during operation without having to add volumes to the measurement. Accuracy can be increased by averaging over a certain period of time. In one embodiment, a running average can be used for assignment and detection of perforation between the two cavities with periodic measurements every 15 seconds.

[0047] Since the device is familiar with the setting of such a medical procedure, compliance ranges can assign the device to connect to the larger or smaller cavity. These compliance ranges are determined in advance.

Claims

Patent claims: 1.) System for insufflation during a transanal total mesorectal excision with two identical insufflators, each of the two insufflators containing a) gas connection for a gas bottle or domestic gas (1) b) pressure and flow control unit (2) equipped with a proportional valve, c) supply line (3) with controllable valve (4), at least one gas pressure sensor (5), at least one gas flow sensor (6) and connection to a first trocar (7) in a cavity (8), d) computing unit (14) with memory for controlling the insufflation, evaluating the measured data and coordinating with the other device, wherein the first insufflator insufflates a first cavity, wherein the second insufflator insufflates a second cavity, wherein the two cavities are separated by a membrane at the beginning of the procedure, characterized in that each of the two insufflators is designed to independently adjust the respective cavity size determine,to save the determined cavity size and to compare it with the cavity size determined by the other insufflator, each of the two insufflators is set up to independently detect the rhythm of the measurement pauses of the other insufflator by determining the pressure of the insufflated cavity at a constant insufflation power, each of the two insufflators is set up to independently detect the rhythm of the measurement pauses of the other insufflator by determining the pressure of the insufflated cavity at a constant insufflation power, each of the two insufflators is set up to independently set its own measurement pauses in such a way that they do not coincide with the measurement pauses of the other insufflator, each of the two insufflators is set up to, independently of each other, to detect the union of the cavities, wherein the insufflator insufflating the smaller cavity stops the insufflation upon detecting the union of the cavities and the entire insufflation takes place after the union of the cavities via the insufflator of the larger cavity. 2.) System according to claim 1, characterized in that the The insufflator connected to the smaller cavity after comparing the cavity sizes is prepared for rectal insufflation, and the insufflator connected to the larger cavity after comparing the cavity sizes is prepared for abdominal insufflation. 3.) System according to claim 1, characterized in that each of the two Insufflators are designed to independently detect the measurement pauses of the other insufflator, with the measurement pauses lasting approximately 0.1 to 0.5 seconds and being inserted at intervals of every 2.5 to 3 seconds. 4.) System according to claim 1, characterized in that the rectally insufflating insufflator can detect a sudden pressure drop of 3-5 mm Hg to the level of abdominal pressure.