WO2021216981A1 - Simulated abdominal cavity for laparoscopic surgery - Google Patents

Simulated abdominal cavity for laparoscopic surgery Download PDF

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Publication number
WO2021216981A1
WO2021216981A1 PCT/US2021/028813 US2021028813W WO2021216981A1 WO 2021216981 A1 WO2021216981 A1 WO 2021216981A1 US 2021028813 W US2021028813 W US 2021028813W WO 2021216981 A1 WO2021216981 A1 WO 2021216981A1
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WO
WIPO (PCT)
Prior art keywords
abdominal cavity
recited
cylinder
pressure
volume
Prior art date
Application number
PCT/US2021/028813
Other languages
French (fr)
Inventor
Emily Thompson
Daniel Britain Hazelbaker STRAUB
Ankit SHUKLA
Satyam SHUKLA
Jacob William Peacock RILEY
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Conmed Corporation
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Publication date
Application filed by Conmed Corporation filed Critical Conmed Corporation
Publication of WO2021216981A1 publication Critical patent/WO2021216981A1/en

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Classifications

    • GPHYSICS
    • G09EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09BEDUCATIONAL OR DEMONSTRATION APPLIANCES; APPLIANCES FOR TEACHING, OR COMMUNICATING WITH, THE BLIND, DEAF OR MUTE; MODELS; PLANETARIA; GLOBES; MAPS; DIAGRAMS
    • G09B23/00Models for scientific, medical, or mathematical purposes, e.g. full-sized devices for demonstration purposes
    • G09B23/28Models for scientific, medical, or mathematical purposes, e.g. full-sized devices for demonstration purposes for medicine
    • G09B23/285Models for scientific, medical, or mathematical purposes, e.g. full-sized devices for demonstration purposes for medicine for injections, endoscopy, bronchoscopy, sigmoidscopy, insertion of contraceptive devices or enemas
    • GPHYSICS
    • G09EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09BEDUCATIONAL OR DEMONSTRATION APPLIANCES; APPLIANCES FOR TEACHING, OR COMMUNICATING WITH, THE BLIND, DEAF OR MUTE; MODELS; PLANETARIA; GLOBES; MAPS; DIAGRAMS
    • G09B23/00Models for scientific, medical, or mathematical purposes, e.g. full-sized devices for demonstration purposes
    • G09B23/28Models for scientific, medical, or mathematical purposes, e.g. full-sized devices for demonstration purposes for medicine
    • G09B23/288Models for scientific, medical, or mathematical purposes, e.g. full-sized devices for demonstration purposes for medicine for artificial respiration or heart massage

Definitions

  • the subject invention is directed to a simulated abdominal cavity for adult and pediatric volumes with simulated ventilation, multiple ports for cannulas and data gathering for testing, training, demonstration or other purposes.
  • Laparoscopic or "minimally invasive" surgical techniques are becoming commonplace in the performance of procedures such as cholecystectomies, appendectomies, hernia repair and nephrectomies. Benefits of such procedures include reduced trauma to the patient, reduced opportunity for infection, and decreased recovery time.
  • Such procedures within the abdominal (peritoneal) cavity are typically performed through a device known as a trocar or cannula, which facilitates the introduction of laparoscopic instruments into the abdominal cavity of a patient.
  • These procedures often require expanding the abdominal cavity such that surgeons have increased visibility and mobility of instruments, this process is done by an insufflator. Insufflators provide a required amount of pressure to keep the abdominal cavity expanded while the patient is undergoing anesthesia.
  • the patient typically has steady breathing but can have bursts of fast or delayed breathing, the insuflators react accordingly to ensure the cavity wall does not collapse and that ambient air does not enter the cavity.
  • the most common gas used in this manner is carbon dioxide, because it is non-flammable, colorless, and dissolves readily in blood.
  • Devices have been developed for the use as an artificial abdominal cavity in which a laparoscopic surgical procedure may be simulated for testing, demonstration, training or other purposes. These devices typically include a simulated abdominal wall, which obstructs a view of a simulated operative site, and a mechanism for remotely viewing the simulated operative site.
  • a simulator may be constructed to represent the conditions expected for a particular procedure on a particular type of patient. Since each surgical procedure is unique, various techniques may be practiced more readily on a simulator that is adjustable to accommodate a unique expected operating environment
  • WO2015138982A1 discloses a simulated abdominal wall that can be penetrated with a trocar.
  • the simulated abdominal cavity contains receptacles which hold tissue simulations.
  • the tissue simulator moves to simulate insufflation.
  • U.S. Patent No. 9,087,458 discloses an abdominal cavity in a manikin that contains an array of inflatable bladders that can be individually inflated, and covered by a synthetic skin.
  • the device uses electronic control and features a GUI and is mainly used for training routines.
  • U.S. Patent No. 8,469,716 discloses a device with a frame that is covered by three layers of artificial skin and flesh to simulate the skin and abdominal wall. There is a port for endoscopy and the camera feed is relayed to a monitor. The device is mainly used by surgeons to practice endoscopic surgery, and its primary objective is to block the surgeon's view.
  • Another device known in the art is the AbdoMAN, which is an artificial abdominal wall simulator for bio-mechanical studies on laparotomy closure techniques. It comprises of a layer of artificial skin, a bladder, pressure transducers, and actuators to facilitate the effects of muscle contractions. The device can measure and moderate IAP, as well as generate IAP fluctuations. This device is used to test closure techniques.
  • the subject disclosure is directed to a new and useful simulated abdominal cavity for laparoscopic surgery, which includes a support stand including a base plate and a pair of spaced apart vertical brackets, a cylinder mounted to the support stand between the vertical brackets to simulate an abdominal cavity, an end cap mounted to a top end of the cylinder, a piston operatively associated with an interior of the cylinder to simulate a diaphragm, an actuator operatively associated with the base plate and the piston for stroking the piston up and down within the cylinder, and a pressure transducer operatively associated with the piston, whereby the piston is adapted and configured to simulate changes in volume and pressure within the cylinder as it is stroked up and down by the actuator and induce pressure changes the abdomen would experience during breathing.
  • the cylinder can be formed from clear acrylic plastic tubing and is about 7.5 inches in length and about 10 inches in inner diameter with a wall thickness of about 0.25 inches, so that it supplies a volume of about 5.15 L.
  • the end cap can include at least one port for retaining a trocar or providing data instrumentation access.
  • the end cap can also include a plurality of ports circumferentially disposed about a central port.
  • the end cap includes a top section having a first semi-circular section, a second semi-circular section, a first flange for receiving a first latch, and a second flange for receiving a second latch, where each of the latches can be coupled to a corresponding vertical bracket and the end cap can include a bottom section having a landing for receiving an O-ring seal.
  • the end cap can include a rigid material and rigid boundaries define the simulated abdominal cavity.
  • the cylinder can be mounted to each of the vertical brackets by a plurality of attachment plates, wherein each attachment plate is solvent welded to an outer surface of the cylinder.
  • the cylinder can be transparent.
  • a pressure sensor and the pressure transducer can be housed within the cylinder attached to an underside of the end cap.
  • a bottom end of the piston is open to an outside of the cylinder.
  • the piston can cyclically move between a maximum volume position and a minimum volume positon based on a pre-programmed volume-pressure curve stored within a software architecture.
  • the maximum volume position of the piston is above a bottom end of the cylinder.
  • the pressure and volume within the cylinder can be controlled by the software architecture where a first sub system of the software architecture includes a graphical user interface (GUI) used to receive inputs from a user and display data, and a second sub- system having a script to facilitate a feedback loop and controls of the actuator.
  • GUI graphical user interface
  • the first sub system is further configured to create and operate the GUI and establish and send data through a serial connection with the second subsystem.
  • the second sub-system is responsible for serial data from the GUI, reading pressure from the pressure transducer, calculating a required volume corresponding to the read pressure, commanding the actuator to move, and relaying pressure and volume data back to the GUI.
  • the required volume is based on pressure-volume curve having both linear and non-linear regions.
  • Fig. 1 is a perspective view of the simulated abdominal cavity of the subject invention
  • Fig. 2 is an exploded perspective view of the simulated abdominal cavity shown in Fig. 1, with parts separated for ease of illustration;
  • Fig. 3 is a detailed view of an end cap of the abdominal cavity of Fig. 1;
  • FIG. 4 is an illustration of a graphical user interface (GUI) for use with the simulated abdominal cavity of the subject invention
  • Fig. 5 is a flow chart depicting the control logic and data flow for the software that is associated with the GUI of the simulated abdominal cavity of the subject invention
  • Fig. 6 is a flow chart depicting the feedback loop associated with the GUI of the simulated abdominal cavity of the subject invention.
  • Fig. 7 is an illustration of a fitted curve with a P set of 15mmHg and a compliance of 0.2 L/mmHg for taking pressure readings from simulated abdominal cavity of the subject invention.
  • the simulated abdominal cavity device 100 of the subject disclosure allows instantaneous and accurate pressure and volume measurements while simulating the abdominal cavity during laparoscopic insufflation.
  • This device 100 can also be used to simulate any type of patient (e.g. adult, pediatric, obese, pregnant, etc.) and can simulate the effects due to breathing as well as be modified for additional simulations such as surgical smoke generation and muscle contractions. Additionally, the device 100 can simulate the effects of breathing and ventilation.
  • a “breathing switch” is turned on, a piston 114 within the device 100 will begin to oscillate up and down. As the piston 114 oscillates with end cap 112 above it, it will cause positive and negative pressure spikes for which the insufflator will need to compensate, thus providing a realistic testing atmosphere for the insufflator.
  • the simulated abdominal cavity device 100 stands vertically and preferred to be about 23” tall and contains a 7.5”-long, 10”-Inner Diameter clear acrylic cylinder 102 that offers 4.8 Liters of total volume. The volume is preferred in order to best simulate a maximum and minimum known abdominal volume for various patients.
  • the device 100 includes a support stand 104 having a base plate 130 and a pair of spaced apart vertical brackets 108. Vertical brackets 108 are made of 80/20 extruded aluminum.
  • the cylinder 102 is mounted between the vertical brackets 108.
  • Polycarbonate plates 109 are used to mount the acrylic cylinder 102 to the brackets 108 and are each machined out of 6 mm- thick plates.
  • the outer dimensions of the machined plates 109 are 2.10" x 1.75".
  • Four plates 109 hold the cylinder from each side. All eight plates 109 are solvent welded to the acrylic cylinder 102 using dichloromethane which creates a structural chemical bond between the two materials.
  • the base plate 130 is used to house the electronics such as (Microcontroller 402, motor driver, and power supply) and support the actuator 116.
  • the base plate 130 is 1/4"- thick black anodized aluminum 6061. This part is machined or cut by water jet to be approximately 12.000" x 12.400" inches.
  • the plate 130 features two slots 131 in the center of the plate to facilitate the alignment of the actuator 116 during assembly of the device 100. It also contains other mounting holes for L-brackets 110 and for the electronics enclosure.
  • Fig. 3 shows a detailed view of the end cap 112.
  • the end cap 112 is mounted to a top end of the cylinder 102 to seal the cylinder 102 from above.
  • the end cap 112 is designed out of ABS plastic to properly seal the device 100 along with a specialized static O-ring 112a.
  • the end cap 112 includes a plurality of ports 115 circumferentially disposed about a central port 115a for providing data instrumentation and trocar access.
  • Each of the ports 115/115a include of a cable gland 117 and grommet 119 (shown in Fig. 2).
  • the cable gland 117 houses the cable grommet 119 that seals to the outer diameter of a trocar when it is inserted into the port.
  • the end cap 112 includes a top section 140 including a first semi- circular section 142, a second semi-circular section 144, a first flange 146 for attaching to a first latch 148, and a second flange 150 for attaching a second latch 152.
  • This design allows the end cap 112 to seal a circular cylinder 102 and piston 114 while also being able to attach to brackets 108, where each of the latches 148/152 (shown in Fig. 2) are coupled to a corresponding vertical bracket 108.
  • the end cap 112 includes a bottom section 160 having a landing 162 for receiving an O-ring seal 112a
  • the end cap 112 is secured down using the spring-loaded draw latches 148/152; with this design, the end cap 112 can easily be removed from the device 100 for maintenance or any other reasons.
  • the bottom of the end cap 112 also includes a pressure transducer 170 and a pressure sensor (PCB) 172 (shown in Fig. 2). A pressure reading is taken from the pressure transducer 170, and a corresponding volume are calculated from a fitted curve, the necessary position of the piston 114 within the cylinder 102 can be calculated based on defined compliance curve parameters.
  • piston 114 is located within the cylinder 102 to change the volume of the simulated abdominal cavity.
  • the piston 114 simulates the diaphragm, it is manufactured out of 1.5"-thick black ABS plastic sheet; the piston 114 needs to be thick enough to counteract any moment on it due to potential misalignment of the actuator 116 and also thick enough to accommodate two reciprocal O-rings 114a/l 14b that sit in respective grooves.
  • the top side 180 of the piston 114 is plain and the underside 182 is shelled out approximately one inch to save on the total height of the device 100.
  • An actuator 116 rises from the base plate 130 and strokes the piston 114 up and down within the cylinder 102.
  • a bottom end 182 of the piston 114 is open to outside of the cylinder.
  • the maximum volume position of the piston 114 does not reach the bottom end of the cylinder 102 ensuring that the cylinder 102 is never depressurized from the bottom.
  • the piston 114 cyclically moves between a maximum volume position to simulate breathing, towards a bottom end of the cylinder 102, and a minimum volume positon based on a pre programmed volume-pressure curve stored within a software architecture (as can be seen in Fig. 7).
  • the maximum and minimum positions can differ from individual runs, based on preselected or pre-programmed patient information.
  • the piston 114 features two custom O- ring grooves 114a/l 14b to support the O-rings; the O-rings are specified according to AS568 standards and are for dynamic applications.
  • the end cap 112 also features a static O-ring 112a that will be responsible for sealing the cylinder 102.
  • Two cables 190/192 extend from the device 100: USB cable 190 that interfaces with a user’s laptop or other similarly capable device to facilitate serial communication and a cable 192 used to power the device 100.
  • pressure and volume within the cylinder is controlled by a software architecture with a first sub system being a graphical user interface (GUI) 400, is used to receive inputs from a user and display data, and a second sub-system being a script to facilitate a feedback loop 600 (shown in Fig. 6) and controls of the actuator.
  • GUI graphical user interface
  • the GUI 400 is responsible for obtaining user input to the device 100 and the microcontroller 402 is used to read from the PCB 172 and control the actuator 116, and it is illustrated in Fig. 4. These two sub-systems are in constant communication through a serial communication protocol.
  • the first sub system operates the GUI 400, establishes, and sends data through a serial connection with the microcontroller 402.
  • the second sub-system is responsible for serial data from the GUI 400, reading pressure from the pressure transducer 170, calculating a required volume corresponding to the read pressure, commanding the actuator 116 to move, and relaying pressure and volume data back to the GUI 400.
  • the GUI 400 will send the second subsystem 402 the user-inputted parameters and the state of the buttons (e.g. “Start”, “Pause”, “Breathing On”, etc.).
  • the Microcontroller 402 Upon receiving these values from the GUI 400, the Microcontroller 402 will respond accordingly, and send data back to the GUI 400 for plotting and exportation.
  • the MATLAB code is responsible for the creation and operation of the GUI 400 and establishing and sending data through a serial connection with the Microcontroller 402.
  • the pressure and volume data is stored on the MATLAB side as it is read in from the Microcontroller 402, and is plotted and displayed in the GUI 400; this data can then be exported to a .CSV file upon clicking the “Stop” button.
  • a piston 114-cylinder 102 plot which shows the current position of the piston 114, a volume-pressure curve, and a pressure-time curve, which will all update simultaneously, along with the data readout fields, as the GUI 400 receives data from the Microcontroller 402.
  • the code features callback functions (essentially software interrupts) that are called when the buttons and input fields are changed on the GUI 400. When these callback functions are called, they send a message to the Microcontroller 402. For example, when the “Start” button is pushed, the GoButtonValueChanged callback is called and sends the message “Ge” to the Microcontroller 402, where “G” means “Start” and “e” means it is the end of the data being sent.
  • the MATLAB GUI 400 also contains a menu to change the sample rate of the device 100 (how often it takes a pressure reading and responds); the options of sample rate are 8, 10, and 20 Hz.
  • the MATLAB code has 21 functions and each are described in more detail below.
  • the Microcontroller 402 code is responsible for receiving messages (serial data) from the GUI 400, reading the pressure from the transducer, calculating the volume corresponding to that pressure, moving the actuator 116, and sending data and messages back to the GUI 400.
  • messages serial data
  • “Normal” operation the device 100 responds to the pressure by moving the piston 114, and also incorporates the breathing dynamics if the breathing switch is turned on in the GUI 400.
  • the piston 114 does not respond to the pressure, but instead “closes” the piston 114 (reduces volume) to create the over pressure, recording pressure and volume data along the way.
  • the code uses fourteen functions which are described in more detail below.
  • Fig. 5 a diagrammatic overview of the software for implementing the subject invention, which refers to the following MATLAB functions:
  • readData Reads pressure and volume data from Microcontroller confirmReadData: When data or messages are sent to the Microcontroller from the GUI, this function prints out the message that was received by the Microcontroller 402 into the GUI console. This is to improve robustness and ensure that the message sent was received properly by the Microcontroller . For instance, if the “Start” button is pushed, the GUI 400 sends “Ge”; upon the reception of “Ge” by the Microcontroller , the Microcontroller will print “Device is starting.” which is then read by this function and printed to the GUI console.
  • writeData Responsible for writing messages to the Microcontroller .
  • createParamStr Creates a parameter char array that contains the four parameters (Pset, Cab, BPM, dV_breathing). For example, ‘bl2v0.09c0.2pl5e’ contains a BPM (‘b’) of 12, dV_breathing ( V) of 0.09 (9%), a Cab (‘c’) of 0.2 L/mmHg, and a Pset (‘p’) of 15 mmHg; the char ‘e’ is sent to denote the end of the data being sent.
  • consolePrint Prints messages to the GUI console.
  • updateGUI Updates the current cavity pressure, cavity volume, and elapsed time fields on the GUI. Also calls GUI plot to update the plots.
  • initializePlots Initializes the plots (clears previous data and resets the piston - cylinder plot). Called in the startupFcn callback.
  • GUIplot Plots the incoming (from Microcontroller ) pressure, volume, and piston 114 position data on the GUI.
  • startupFcn Called when GUI app is booted up. Resets variables, switches, plots, and data fields.
  • GoButtonValueChanged Called when the state of the “Start” button is changed (start or pause). It sends a “start” indicator to Microcontroller , starts the elapsed time clock, and calls the readData function to start reading P,V data from the Microcontroller . This function is also called to pause the device; after the device has been started, the “Start” button will turn orange and the label will change to “Pause”.
  • StopButtonValueChanged Called when state of “Stop” button is changed. Sends a “stop” indicator to Microcontroller (‘Se’ for “stop”), exports a CSV file with the pressure and volume data if the data collection checkbox is checked, and calls the startupFcn to reset the GUI.
  • SetPressuremmhgEditFieldValueChanged Called when the Set Pressure edit field is changed. It calls the createParamStr function to resend the new parameter string to Microcontroller.
  • CabLmmHgSliderValueChanged Called when the Cab slider value is changed. It calls the createParamStr function to resend the new parameter string to Microcontroller.
  • BreathingPercentSpinnerValueChanged Called when the breathing percentage spinner value is changed. It calls the createParamStr function to resend the new parameter string to Microcontroller.
  • BPMSpinnerValueChanged Called when the BPM spinner value is changed. It calls the createParamStr function to resend the new parameter string to Microcontroller.
  • CollectDataCheckBoxValueChanged Tells the MATLAB program that the user wants a CSV file of the P,V data upon pressing the “Stop” button.
  • breathingSwitchValueChanged Called when the breathing switch is changed. Sends an indicator to the Microcontroller (‘Ble’ for on, ‘BOe’ for off).
  • pushTestValueChanged Called when the push test switch is changed. Sends an indicator to the Microcontroller.
  • EightHzMenuSelected Changes the sample rate of the device 100 to 8 Hz. Sends an indicator to the Microcontroller (‘R8e’).
  • TenHzMenuSelected Changes the sample rate of the device 100 to 10 Hz. Sends an indicator to the Microcontroller (‘R10e’).
  • TwentyHzMenuSelected Changes the sample rate of the device 100 to 20 Hz. Sends an indicator to the Microcontroller 402 (‘R20e’).
  • readData() Reads data from the MATLAB GUI (including paramStr and states of the buttons).
  • goBackwards() Called in breathingDynamics( ) and sends a 100% duty cycle PWM value to move the actuator backwards. This is used as opposed to move Actuator () function in which PID control is used (for breathing, PID is not needed, and the linear actuator is moved at full speed).
  • stopMoving() Stops the linear actuator by sending a 0% duty cycle PWM value to both backwards and forwards directions.
  • moveActuator() Called in “normal” operation when the device 100 is responding to the pressure reading.
  • breathing() Calculates the stroke of the piston corresponding to the breathing pattern dictated by the BPM and tidal volume percentage parameters that are inputted on the GUI 400.
  • breathingDynamics() Moves the piston when breathing is called.
  • Fig. 6 shows a flow chart depicting the feedback loop associated with the GUI of the simulated abdominal cavity of the subject invention.
  • PID Proportional, Integral, Derivative
  • the abdominal wall can be modeled as a spring-mass-damper, a linear actuator is used to adjust the spring constant and dampening coefficient to match the model of the patient-specific abdominal cavity.
  • This model of the abdominal cavity is a function of the height, width, and depth of the abdominal cavity as well as body fat which provides the mass of the abdominal wall.
  • the spring constant is deduced from empirical data surrounding the Young’s modulus of the abdominal wall. With the spring constant, the dampening coefficient is deduced. Using feedback control, these parameters are altered instantaneously, giving an accurate response to the insufflation pressure that is representative of in vivo surgeries.
  • a feedforward approach is used instead of a model-matching approach to ensure the compliance curve can be perfectly matched (to within tolerance). Additionally, using a feedforward approach limits the amount of user inputs to the device as well as requires less computational power to execute the calculations, speeding up the device’s response time.
  • a curve can be fitted to that data. Using this curve, two other parameters can be used to match the slope and y-intercept of the linear and non-linear curves at set pressure.
  • a typical compliance curve has a linear and non-linear region. It is assumed, and backed by empirical data, that the transition point between linear and non linear occurs at or around set pressure (typically 15 mmHg).
  • Fig. 7 provides an example of a fully fitted curve 700, where a pressure reading can be taken from a pressure transducer 170, and the corresponding volume can be calculated from the fitted curve. With this volume, the position (stroke) of the piston 114 can be calculated based on the inputted compliance curve parameters. This pressure and volume data will then be communicated back to the MATLAB graphical user interface (GUI 400) for plotting and exporting data.
  • the pres sure- volume curve has both linear 702 and non linear regions 704.
  • the linear region 702 is defined by the compliance of the piston 114 and the current cavity pressure.
  • the non-linear region 704 is define based on a fitted curve to experimental P-V data.
  • this device 100 can provide pressure data to within -0.15 mmHg and a volumetric reading to within ⁇ 12mL which could not have otherwise been determined due to the irregular volume and non-linear elasticity of compliant materials such as silicone.
  • compliant materials such as silicone.
  • the subject device 100 matches any compliance curve inputted to the device 100, essentially simulating a variety of different materials and compliances all in one device. Based on the set pressure and compliance (dV/dP) inputted in the device’s GUI 400, the compliance curve by which the device 100 abides can be altered. That is to say that based on the pressure reading of the device 100, the actuator 116 will move the piston 114 to the designated position dictated by the inputted compliance curve.
  • the device 100 can simulate the effects of breathing and ventilation. As the device 100 insufflates and reaches set pressure, and if the breathing switch is turned on in the GUI 400, the device 100 will begin to oscillate back and forth. This breathing pattern is dictated by the breathing parameters: breath per minute (BPM) and percent volume change. This percent volume change ranges from 9-26% which was supported by average tidal volumes of humans in normal everyday life; it was discovered that tidal volume does not have effects on laparoscopic insufflation, but this functionality has been added to the device 100 nonetheless.
  • the BPM ranges from 12-30 breaths per minute which is also based on data of average BPM of humans in everyday life.
  • the device 100 also incorporates a “push test” to create an over-pressure situation to test how the AirSeal iFS system responds. Because the actuator 116 (rated for 400 lbf) would not allow one to manually push on the piston 114 to create this over-pressure, it has been implemented in the software. From the GUI 400, the user can toggle the “Push Test” rocker switch to “On”. In that event, the device 100 will stop reading and responding to the pressure, and will instead slam closed (reduce the volume) at full speed (0.5”/s). By reducing this volume, the increase in pressure will provide the over-pressure scenario to test the insufflator. While the subject disclosure has been shown and described with reference to preferred embodiments, those skilled in the art will readily appreciate that changes and/or modifications may be made thereto without departing from the scope of the subject disclosure.

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Abstract

A simulated abdominal cavity for laparoscopic surgery including a support stand having a base plate and a pair of spaced apart vertical brackets, a cylinder mounted to the support stand between the vertical brackets to simulate an abdominal cavity volume, an end cap mounted to a top end of the cylinder to seal the cylinder, a piston operatively associated with an interior of the cylinder to affect a volume of a simulated abdominal cavity, an actuator operatively associated with the base plate and the piston to simulate breathing and a pressure transducer operatively associated with the piston, whereby the piston is adapted and configured to simulate changes in volume and pressure within an abdominal cavity as it is stroked up and down by the actuator.

Description

SIMULATED ABDOMINAL CAVITY FOR LAPAROSCOPIC SURGERY
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims priority to and the benefit of U.S. Provisional Application No. 63/014,458, filed April 23, 2020, the entire contents of which are herein incorporated by reference in their entirety.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The subject invention is directed to a simulated abdominal cavity for adult and pediatric volumes with simulated ventilation, multiple ports for cannulas and data gathering for testing, training, demonstration or other purposes.
2. Description of Related Art
Laparoscopic or "minimally invasive" surgical techniques are becoming commonplace in the performance of procedures such as cholecystectomies, appendectomies, hernia repair and nephrectomies. Benefits of such procedures include reduced trauma to the patient, reduced opportunity for infection, and decreased recovery time. Such procedures within the abdominal (peritoneal) cavity are typically performed through a device known as a trocar or cannula, which facilitates the introduction of laparoscopic instruments into the abdominal cavity of a patient. These procedures often require expanding the abdominal cavity such that surgeons have increased visibility and mobility of instruments, this process is done by an insufflator. Insufflators provide a required amount of pressure to keep the abdominal cavity expanded while the patient is undergoing anesthesia. The patient typically has steady breathing but can have bursts of fast or delayed breathing, the insuflators react accordingly to ensure the cavity wall does not collapse and that ambient air does not enter the cavity. The most common gas used in this manner is carbon dioxide, because it is non-flammable, colorless, and dissolves readily in blood.
Devices have been developed for the use as an artificial abdominal cavity in which a laparoscopic surgical procedure may be simulated for testing, demonstration, training or other purposes. These devices typically include a simulated abdominal wall, which obstructs a view of a simulated operative site, and a mechanism for remotely viewing the simulated operative site. A simulator may be constructed to represent the conditions expected for a particular procedure on a particular type of patient. Since each surgical procedure is unique, various techniques may be practiced more readily on a simulator that is adjustable to accommodate a unique expected operating environment
The prior art includes examples of simulated abdominal cavities for performing laparoscopic surgery techniques. For example, WO2015138982A1 discloses a simulated abdominal wall that can be penetrated with a trocar. The simulated abdominal cavity contains receptacles which hold tissue simulations. When the abdominal wall and receptacles are penetrated, the tissue simulator moves to simulate insufflation. U.S. Patent No. 9,087,458 discloses an abdominal cavity in a manikin that contains an array of inflatable bladders that can be individually inflated, and covered by a synthetic skin. The device uses electronic control and features a GUI and is mainly used for training routines.
In addition, U.S. Patent No. 8,469,716 discloses a device with a frame that is covered by three layers of artificial skin and flesh to simulate the skin and abdominal wall. There is a port for endoscopy and the camera feed is relayed to a monitor. The device is mainly used by surgeons to practice endoscopic surgery, and its primary objective is to block the surgeon's view. Another device known in the art is the AbdoMAN, which is an artificial abdominal wall simulator for bio-mechanical studies on laparotomy closure techniques. It comprises of a layer of artificial skin, a bladder, pressure transducers, and actuators to facilitate the effects of muscle contractions. The device can measure and moderate IAP, as well as generate IAP fluctuations. This device is used to test closure techniques.
While the practicing surgery is key to good surgical outcomes, it’s important to ensure that every piece of the operating room is working properly, including insufflators. The devices described above expands and contracts based on command without input from standalone insufflators. The above mentioned references cannot validate or test a separate insufflator. While conventional simulators have generally been considered satisfactory for their intended purpose, there is still a need in the art for abdominal simulators capable of simulating various patient profiles and being able to validate insufflators. The present disclosure provides a solution for this need.
SUMMARY OF THE DISCLOSURE
The subject disclosure is directed to a new and useful simulated abdominal cavity for laparoscopic surgery, which includes a support stand including a base plate and a pair of spaced apart vertical brackets, a cylinder mounted to the support stand between the vertical brackets to simulate an abdominal cavity, an end cap mounted to a top end of the cylinder, a piston operatively associated with an interior of the cylinder to simulate a diaphragm, an actuator operatively associated with the base plate and the piston for stroking the piston up and down within the cylinder, and a pressure transducer operatively associated with the piston, whereby the piston is adapted and configured to simulate changes in volume and pressure within the cylinder as it is stroked up and down by the actuator and induce pressure changes the abdomen would experience during breathing.
In operation, using a pressure reading taken from the pressure transducer, and a corresponding volume calculated from a fitted curve, a position of the piston within the cylinder can be calculated based on defined compliance curve parameters. The pressure and volume data is then communicated to a graphical user interface (GUI) for plotting and exporting data. In an exemplary embodiment of the subject invention, the cylinder can be formed from clear acrylic plastic tubing and is about 7.5 inches in length and about 10 inches in inner diameter with a wall thickness of about 0.25 inches, so that it supplies a volume of about 5.15 L.
In one embodiment of the subject invention the end cap can include at least one port for retaining a trocar or providing data instrumentation access. The end cap can also include a plurality of ports circumferentially disposed about a central port. The end cap includes a top section having a first semi-circular section, a second semi-circular section, a first flange for receiving a first latch, and a second flange for receiving a second latch, where each of the latches can be coupled to a corresponding vertical bracket and the end cap can include a bottom section having a landing for receiving an O-ring seal.
In one embodiment of the subject invention the end cap can include a rigid material and rigid boundaries define the simulated abdominal cavity. The cylinder can be mounted to each of the vertical brackets by a plurality of attachment plates, wherein each attachment plate is solvent welded to an outer surface of the cylinder. The cylinder can be transparent. A pressure sensor and the pressure transducer can be housed within the cylinder attached to an underside of the end cap. A bottom end of the piston is open to an outside of the cylinder.
The piston can cyclically move between a maximum volume position and a minimum volume positon based on a pre-programmed volume-pressure curve stored within a software architecture. The maximum volume position of the piston is above a bottom end of the cylinder. The pressure and volume within the cylinder can be controlled by the software architecture where a first sub system of the software architecture includes a graphical user interface (GUI) used to receive inputs from a user and display data, and a second sub- system having a script to facilitate a feedback loop and controls of the actuator. The feedback loop can include pressure data from the pressure transducer, pressure data from a simulated breathing spike, Proportional, Integral, Derivative (PID) control to change a damping coefficient and a spring constant of the piston modeling equation ms + bx + kx = f where, where m is mass, b is the damping coefficient, k is the spring constant, x is the position of the mass, and f is the input force in order to match a spring constant of a subject abdominal wall. The first sub system is further configured to create and operate the GUI and establish and send data through a serial connection with the second subsystem. The second sub-system is responsible for serial data from the GUI, reading pressure from the pressure transducer, calculating a required volume corresponding to the read pressure, commanding the actuator to move, and relaying pressure and volume data back to the GUI. The required volume is based on pressure-volume curve having both linear and non-linear regions.
These and other features of the simulated abdominal cavity of the subject invention will become more readily apparent to those having ordinary skill in the art to which the subject invention appertains from the detailed description of the preferred embodiments taken in conjunction with the following brief description of the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
So that those skilled in the art will readily understand how to make and use the simulated abdominal cavity of subject invention without undue experimentation, preferred embodiments thereof will be described in detail herein below with reference to the figures wherein:
Fig. 1 is a perspective view of the simulated abdominal cavity of the subject invention;
Fig. 2 is an exploded perspective view of the simulated abdominal cavity shown in Fig. 1, with parts separated for ease of illustration;
Fig. 3 is a detailed view of an end cap of the abdominal cavity of Fig. 1;
Fig. 4 is an illustration of a graphical user interface (GUI) for use with the simulated abdominal cavity of the subject invention;
Fig. 5 is a flow chart depicting the control logic and data flow for the software that is associated with the GUI of the simulated abdominal cavity of the subject invention;
Fig. 6 is a flow chart depicting the feedback loop associated with the GUI of the simulated abdominal cavity of the subject invention; and
Fig. 7 is an illustration of a fitted curve with a Pset of 15mmHg and a compliance of 0.2 L/mmHg for taking pressure readings from simulated abdominal cavity of the subject invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
In the description that follows, reference is made to certain figures and to the appended drawing package which contains part numbers and descriptions of the components and materials used to construct the simulated abdominal cavity of the subject invention.
Referring initially to Fig. 1, the simulated abdominal cavity device 100 of the subject disclosure allows instantaneous and accurate pressure and volume measurements while simulating the abdominal cavity during laparoscopic insufflation. This device 100 can also be used to simulate any type of patient (e.g. adult, pediatric, obese, pregnant, etc.) and can simulate the effects due to breathing as well as be modified for additional simulations such as surgical smoke generation and muscle contractions. Additionally, the device 100 can simulate the effects of breathing and ventilation. As the device 100 insufflates and reaches set pressure, and a “breathing switch” is turned on, a piston 114 within the device 100 will begin to oscillate up and down. As the piston 114 oscillates with end cap 112 above it, it will cause positive and negative pressure spikes for which the insufflator will need to compensate, thus providing a realistic testing atmosphere for the insufflator.
With continuing reference to Fig. 1 in conjunction with Fig. 2, the simulated abdominal cavity device 100 stands vertically and preferred to be about 23” tall and contains a 7.5”-long, 10”-Inner Diameter clear acrylic cylinder 102 that offers 4.8 Liters of total volume. The volume is preferred in order to best simulate a maximum and minimum known abdominal volume for various patients. The device 100 includes a support stand 104 having a base plate 130 and a pair of spaced apart vertical brackets 108. Vertical brackets 108 are made of 80/20 extruded aluminum. The cylinder 102 is mounted between the vertical brackets 108. Polycarbonate plates 109 are used to mount the acrylic cylinder 102 to the brackets 108 and are each machined out of 6 mm- thick plates. The outer dimensions of the machined plates 109 are 2.10" x 1.75". Four plates 109 hold the cylinder from each side. All eight plates 109 are solvent welded to the acrylic cylinder 102 using dichloromethane which creates a structural chemical bond between the two materials.
The base plate 130 is used to house the electronics such as (Microcontroller 402, motor driver, and power supply) and support the actuator 116. The base plate 130 is 1/4"- thick black anodized aluminum 6061. This part is machined or cut by water jet to be approximately 12.000" x 12.400" inches. The plate 130 features two slots 131 in the center of the plate to facilitate the alignment of the actuator 116 during assembly of the device 100. It also contains other mounting holes for L-brackets 110 and for the electronics enclosure.
Fig. 3 shows a detailed view of the end cap 112. The end cap 112 is mounted to a top end of the cylinder 102 to seal the cylinder 102 from above. The end cap 112 is designed out of ABS plastic to properly seal the device 100 along with a specialized static O-ring 112a. The end cap 112 includes a plurality of ports 115 circumferentially disposed about a central port 115a for providing data instrumentation and trocar access. Each of the ports 115/115a include of a cable gland 117 and grommet 119 (shown in Fig. 2). The cable gland 117 houses the cable grommet 119 that seals to the outer diameter of a trocar when it is inserted into the port. The end cap 112 includes a top section 140 including a first semi- circular section 142, a second semi-circular section 144, a first flange 146 for attaching to a first latch 148, and a second flange 150 for attaching a second latch 152. This design allows the end cap 112 to seal a circular cylinder 102 and piston 114 while also being able to attach to brackets 108, where each of the latches 148/152 (shown in Fig. 2) are coupled to a corresponding vertical bracket 108. The end cap 112 includes a bottom section 160 having a landing 162 for receiving an O-ring seal 112a The end cap 112 is secured down using the spring-loaded draw latches 148/152; with this design, the end cap 112 can easily be removed from the device 100 for maintenance or any other reasons. The bottom of the end cap 112 also includes a pressure transducer 170 and a pressure sensor (PCB) 172 (shown in Fig. 2). A pressure reading is taken from the pressure transducer 170, and a corresponding volume are calculated from a fitted curve, the necessary position of the piston 114 within the cylinder 102 can be calculated based on defined compliance curve parameters.
Referring again to Figs. 1 and 2, piston 114 is located within the cylinder 102 to change the volume of the simulated abdominal cavity. The piston 114 simulates the diaphragm, it is manufactured out of 1.5"-thick black ABS plastic sheet; the piston 114 needs to be thick enough to counteract any moment on it due to potential misalignment of the actuator 116 and also thick enough to accommodate two reciprocal O-rings 114a/l 14b that sit in respective grooves. The top side 180 of the piston 114 is plain and the underside 182 is shelled out approximately one inch to save on the total height of the device 100. An actuator 116 rises from the base plate 130 and strokes the piston 114 up and down within the cylinder 102. A bottom end 182 of the piston 114 is open to outside of the cylinder.
The maximum volume position of the piston 114 does not reach the bottom end of the cylinder 102 ensuring that the cylinder 102 is never depressurized from the bottom. The piston 114 cyclically moves between a maximum volume position to simulate breathing, towards a bottom end of the cylinder 102, and a minimum volume positon based on a pre programmed volume-pressure curve stored within a software architecture (as can be seen in Fig. 7). The maximum and minimum positions can differ from individual runs, based on preselected or pre-programmed patient information. The piston 114 features two custom O- ring grooves 114a/l 14b to support the O-rings; the O-rings are specified according to AS568 standards and are for dynamic applications. The end cap 112 also features a static O-ring 112a that will be responsible for sealing the cylinder 102. Two cables 190/192 extend from the device 100: USB cable 190 that interfaces with a user’s laptop or other similarly capable device to facilitate serial communication and a cable 192 used to power the device 100.
Referring to Fig. 4, pressure and volume within the cylinder is controlled by a software architecture with a first sub system being a graphical user interface (GUI) 400, is used to receive inputs from a user and display data, and a second sub-system being a script to facilitate a feedback loop 600 (shown in Fig. 6) and controls of the actuator. There are two main electrical sub-systems: the MATLAB GUI 400 (first) and the microcontroller 402 (the Microcontroller code or second sub- system). The GUI 400 is responsible for obtaining user input to the device 100 and the microcontroller 402 is used to read from the PCB 172 and control the actuator 116, and it is illustrated in Fig. 4. These two sub-systems are in constant communication through a serial communication protocol. The first sub system operates the GUI 400, establishes, and sends data through a serial connection with the microcontroller 402. The second sub-system is responsible for serial data from the GUI 400, reading pressure from the pressure transducer 170, calculating a required volume corresponding to the read pressure, commanding the actuator 116 to move, and relaying pressure and volume data back to the GUI 400. The GUI 400 will send the second subsystem 402 the user-inputted parameters and the state of the buttons (e.g. “Start”, “Pause”, “Breathing On”, etc.). Upon receiving these values from the GUI 400, the Microcontroller 402 will respond accordingly, and send data back to the GUI 400 for plotting and exportation.
The MATLAB code is responsible for the creation and operation of the GUI 400 and establishing and sending data through a serial connection with the Microcontroller 402. The pressure and volume data is stored on the MATLAB side as it is read in from the Microcontroller 402, and is plotted and displayed in the GUI 400; this data can then be exported to a .CSV file upon clicking the “Stop” button.
There are three possible plots in the GUI 400: a piston 114-cylinder 102 plot which shows the current position of the piston 114, a volume-pressure curve, and a pressure-time curve, which will all update simultaneously, along with the data readout fields, as the GUI 400 receives data from the Microcontroller 402. The code features callback functions (essentially software interrupts) that are called when the buttons and input fields are changed on the GUI 400. When these callback functions are called, they send a message to the Microcontroller 402. For example, when the “Start” button is pushed, the GoButtonValueChanged callback is called and sends the message “Ge” to the Microcontroller 402, where “G” means “Start” and “e” means it is the end of the data being sent. The MATLAB GUI 400 also contains a menu to change the sample rate of the device 100 (how often it takes a pressure reading and responds); the options of sample rate are 8, 10, and 20 Hz. The MATLAB code has 21 functions and each are described in more detail below.
The Microcontroller 402 code is responsible for receiving messages (serial data) from the GUI 400, reading the pressure from the transducer, calculating the volume corresponding to that pressure, moving the actuator 116, and sending data and messages back to the GUI 400. There are two main modes of the operation: “Normal” and “Push Test”. In “Normal” operation, the device 100 responds to the pressure by moving the piston 114, and also incorporates the breathing dynamics if the breathing switch is turned on in the GUI 400. During the “Push Test” operation, the piston 114 does not respond to the pressure, but instead “closes” the piston 114 (reduces volume) to create the over pressure, recording pressure and volume data along the way. The code uses fourteen functions which are described in more detail below.
Referring now to Fig. 5, a diagrammatic overview of the software for implementing the subject invention, which refers to the following MATLAB functions: readData: Reads pressure and volume data from Microcontroller confirmReadData: When data or messages are sent to the Microcontroller from the GUI, this function prints out the message that was received by the Microcontroller 402 into the GUI console. This is to improve robustness and ensure that the message sent was received properly by the Microcontroller . For instance, if the “Start” button is pushed, the GUI 400 sends “Ge”; upon the reception of “Ge” by the Microcontroller , the Microcontroller will print “Device is starting.” which is then read by this function and printed to the GUI console. writeData: Responsible for writing messages to the Microcontroller . createParamStr: Creates a parameter char array that contains the four parameters (Pset, Cab, BPM, dV_breathing). For example, ‘bl2v0.09c0.2pl5e’ contains a BPM (‘b’) of 12, dV_breathing ( V) of 0.09 (9%), a Cab (‘c’) of 0.2 L/mmHg, and a Pset (‘p’) of 15 mmHg; the char ‘e’ is sent to denote the end of the data being sent. consolePrint: Prints messages to the GUI console. updateGUI: Updates the current cavity pressure, cavity volume, and elapsed time fields on the GUI. Also calls GUI plot to update the plots. initializePlots: Initializes the plots (clears previous data and resets the piston - cylinder plot). Called in the startupFcn callback.
GUIplot: Plots the incoming (from Microcontroller ) pressure, volume, and piston 114 position data on the GUI.
The following MATLAB Callbacks are also used: startupFcn: Called when GUI app is booted up. Resets variables, switches, plots, and data fields.
GoButtonValueChanged: Called when the state of the “Start” button is changed (start or pause). It sends a “start” indicator to Microcontroller , starts the elapsed time clock, and calls the readData function to start reading P,V data from the Microcontroller . This function is also called to pause the device; after the device has been started, the “Start” button will turn orange and the label will change to “Pause”.
StopButtonValueChanged: Called when state of “Stop” button is changed. Sends a “stop” indicator to Microcontroller (‘Se’ for “stop”), exports a CSV file with the pressure and volume data if the data collection checkbox is checked, and calls the startupFcn to reset the GUI. SetPressuremmhgEditFieldValueChanged: Called when the Set Pressure edit field is changed. It calls the createParamStr function to resend the new parameter string to Microcontroller.
CabLmmHgSliderValueChanged: Called when the Cab slider value is changed. It calls the createParamStr function to resend the new parameter string to Microcontroller.
BreathingPercentSpinnerValueChanged: Called when the breathing percentage spinner value is changed. It calls the createParamStr function to resend the new parameter string to Microcontroller.
BPMSpinnerValueChanged: Called when the BPM spinner value is changed. It calls the createParamStr function to resend the new parameter string to Microcontroller.
CollectDataCheckBoxValueChanged: Tells the MATLAB program that the user wants a CSV file of the P,V data upon pressing the “Stop” button. breathingSwitchValueChanged: Called when the breathing switch is changed. Sends an indicator to the Microcontroller (‘Ble’ for on, ‘BOe’ for off). pushTestValueChanged: Called when the push test switch is changed. Sends an indicator to the Microcontroller.
EightHzMenuSelected: Changes the sample rate of the device 100 to 8 Hz. Sends an indicator to the Microcontroller (‘R8e’).
TenHzMenuSelected: Changes the sample rate of the device 100 to 10 Hz. Sends an indicator to the Microcontroller (‘R10e’).
TwentyHzMenuSelected: Changes the sample rate of the device 100 to 20 Hz. Sends an indicator to the Microcontroller 402 (‘R20e’).
The following Microcontroller Functions ae also used: setup(): Called once upon powering the Microcontroller on. Resets variables and homes the linear actuator. loop(): Continuously runs as long as Microcontroller 402 is powered. In this function, all the following functions are called depending on the state of the device 100 (started, paused, breathing on, etc.) writeData(): Sends P,V data to the MATLAB GUI. readData(): Reads data from the MATLAB GUI (including paramStr and states of the buttons). defineCabCurve(): The Cab curve is determined by using the method explained above. This function outputs the fitting parameters needed to calculate the volume corresponding to the pressure reading. homingO: Fully retracts the linear actuator and resets the Hall effect sensor count. If any counts have been skipped, this will reset the error. This function is called in the setup( ) function as well as when the “Stop” button has been pressed (StopButtonValueChanged) on the MATLAB side. speedO: Interrupt called when position of linear actuator changes. This interrupt is connected to one of the Hall effect sensors of the linear actuator and keeps track of the counts. speedl: Interrupt called when position of linear actuator changes. This interrupt is connected to the other Hall effect sensor. This function keeps track of the counts. goForwards(): Called in breathingDynamics( ) and sends a 100% duty cycle PWM value to move the actuator forwards. This is used as opposed to moveActuator( ) function in which PID control is used (for breathing, PID is not needed, and the linear actuator is moved at full speed). goBackwards(): Called in breathingDynamics( ) and sends a 100% duty cycle PWM value to move the actuator backwards. This is used as opposed to move Actuator () function in which PID control is used (for breathing, PID is not needed, and the linear actuator is moved at full speed). stopMoving(): Stops the linear actuator by sending a 0% duty cycle PWM value to both backwards and forwards directions. moveActuator(): Called in “normal” operation when the device 100 is responding to the pressure reading. It incorporates a PID controller (from Microcontroller 402’ s PID library). This function is capable of moving the piston forwards, backwards, and stopping the actuator. breathing(): Calculates the stroke of the piston corresponding to the breathing pattern dictated by the BPM and tidal volume percentage parameters that are inputted on the GUI 400. breathingDynamics(): Moves the piston when breathing is called.
Fig. 6 shows a flow chart depicting the feedback loop associated with the GUI of the simulated abdominal cavity of the subject invention. The feedback loop 600 includes pressure data from the pressure transducer 602, pressure data from a breathing spike 604, Proportional, Integral, Derivative (PID) control 606 to change a damping coefficient and a spring constant of the piston 114 modeling equation s + hi + kx = f where, where m is mass, b is the damping coefficient, k is the spring constant, x is the position of the mass, and f is the input force in order to match a spring constant of a subject abdominal wall. The abdominal wall can be modeled as a spring-mass-damper, a linear actuator is used to adjust the spring constant and dampening coefficient to match the model of the patient-specific abdominal cavity. This model of the abdominal cavity is a function of the height, width, and depth of the abdominal cavity as well as body fat which provides the mass of the abdominal wall. From here, the spring constant is deduced from empirical data surrounding the Young’s modulus of the abdominal wall. With the spring constant, the dampening coefficient is deduced. Using feedback control, these parameters are altered instantaneously, giving an accurate response to the insufflation pressure that is representative of in vivo surgeries.
It is advantageous to validate to available data, a feedforward approach is used instead of a model-matching approach to ensure the compliance curve can be perfectly matched (to within tolerance). Additionally, using a feedforward approach limits the amount of user inputs to the device as well as requires less computational power to execute the calculations, speeding up the device’s response time. Based on the two data sets from McDougall and Abu-Rafea, a curve can be fitted to that data. Using this curve, two other parameters can be used to match the slope and y-intercept of the linear and non-linear curves at set pressure. A typical compliance curve has a linear and non-linear region. It is assumed, and backed by empirical data, that the transition point between linear and non linear occurs at or around set pressure (typically 15 mmHg).
Fig. 7 provides an example of a fully fitted curve 700, where a pressure reading can be taken from a pressure transducer 170, and the corresponding volume can be calculated from the fitted curve. With this volume, the position (stroke) of the piston 114 can be calculated based on the inputted compliance curve parameters. This pressure and volume data will then be communicated back to the MATLAB graphical user interface (GUI 400) for plotting and exporting data. The pres sure- volume curve has both linear 702 and non linear regions 704. The linear region 702 is defined by the compliance of the piston 114 and the current cavity pressure. The non-linear region 704 is define based on a fitted curve to experimental P-V data. The linear region 702 is defined by V = CabP + V0 where Cab is the compliance inputted by the user, P is the cavity pressure, V0 is the initial volume which gives enough room between the piston 114 and end cap 112 for the trocars and electronics, and V is the cavity volume. To provide sufficient space, the initial volume V0 of the piston 114-cylinder 102 device 100 will provide the necessary clearance between the top of the piston 114 and the bottom of the end cap 112.
In comparison with the reference simulation devices, the subject device of the disclosure offers more functionality and provides more concrete test data. Namely, this device 100 can provide pressure data to within -0.15 mmHg and a volumetric reading to within ~12mL which could not have otherwise been determined due to the irregular volume and non-linear elasticity of compliant materials such as silicone. In other words, as the two- sheet device is insufflated, it deforms into a dome shape, giving a shape and volume that is difficult to measure.
Because it is difficult to model and specify materials that abide by a specific compliance curve (to within +/- 30%), the subject device 100 matches any compliance curve inputted to the device 100, essentially simulating a variety of different materials and compliances all in one device. Based on the set pressure and compliance (dV/dP) inputted in the device’s GUI 400, the compliance curve by which the device 100 abides can be altered. That is to say that based on the pressure reading of the device 100, the actuator 116 will move the piston 114 to the designated position dictated by the inputted compliance curve.
Additionally, the device 100 can simulate the effects of breathing and ventilation. As the device 100 insufflates and reaches set pressure, and if the breathing switch is turned on in the GUI 400, the device 100 will begin to oscillate back and forth. This breathing pattern is dictated by the breathing parameters: breath per minute (BPM) and percent volume change. This percent volume change ranges from 9-26% which was supported by average tidal volumes of humans in normal everyday life; it was discovered that tidal volume does not have effects on laparoscopic insufflation, but this functionality has been added to the device 100 nonetheless. The BPM ranges from 12-30 breaths per minute which is also based on data of average BPM of humans in everyday life. As the piston 114 oscillates back and forth, it will cause positive and negative pressure spikes for which the insufflator will need to compensate, thus providing a realistic testing atmosphere for the insufflator.
The device 100 also incorporates a “push test” to create an over-pressure situation to test how the AirSeal iFS system responds. Because the actuator 116 (rated for 400 lbf) would not allow one to manually push on the piston 114 to create this over-pressure, it has been implemented in the software. From the GUI 400, the user can toggle the “Push Test” rocker switch to “On”. In that event, the device 100 will stop reading and responding to the pressure, and will instead slam closed (reduce the volume) at full speed (0.5”/s). By reducing this volume, the increase in pressure will provide the over-pressure scenario to test the insufflator. While the subject disclosure has been shown and described with reference to preferred embodiments, those skilled in the art will readily appreciate that changes and/or modifications may be made thereto without departing from the scope of the subject disclosure.

Claims

WHAT IS CLAIMED:
1. A simulated abdominal cavity for laparoscopic surgery, comprising: a support stand including a base plate and a pair of spaced apart vertical brackets; a cylinder mounted to the support stand between the vertical brackets to simulate an abdominal cavity volume; an end cap mounted to a top end of the cylinder to seal the cylinder; a piston operatively associated with an interior of the cylinder to affect a volume of a simulated abdominal cavity; an actuator operatively associated with the base plate and the piston for stroking the piston up and down within the cylinder; and a pressure transducer operatively associated with the piston, whereby the piston is adapted and configured to simulate changes in volume and pressure within an abdominal cavity as it is stroked up and down by the actuator.
2. The simulated abdominal cavity as recited in Claim 1, wherein using a pressure reading taken from the pressure transducer, and a corresponding volume calculated from a fitted curve, a position of the piston within the cylinder can be calculated based on defined compliance curve parameters.
3. The simulated abdominal cavity as recited in Claim 1, wherein the end cap includes at least one port for retaining a trocar or providing data instrumentation access.
4. The simulated abdominal cavity as recited in Claim 1, wherein the end cap includes a plurality of ports circumferentially disposed about a central port.
5. The simulated abdominal cavity as recited in Claim 1, wherein the end cap includes a top section including a first semi-circular section, a second semi-circular section, a first flange for receiving a first latch, and a second flange for receiving a second latch.
6. The simulated abdominal cavity as recited in Claim 5, wherein each of the latches are coupled to a corresponding vertical bracket.
7. The simulated abdominal cavity as recited in Claim 5, wherein the end cap includes a bottom section having a landing for receiving an O-ring seal.
8. The simulated abdominal cavity as recited in Claim 1, wherein the end cap includes a rigid material.
9. The simulated abdominal cavity as recited in Claim 1, wherein the cylinder is mounted to each of the vertical brackets by a plurality of attachment plates, wherein each attachment plate is solvent welded to an outer surface of the cylinder.
10. The simulated abdominal cavity as recited in Claim 1, wherein the cylinder is transparent.
11. The simulated abdominal cavity as recited in Claim 1, wherein rigid boundaries define the simulated abdominal cavity.
12. The simulated abdominal cavity as recited in Claim 1, wherein a pressure sensor and the pressure transducer are housed within the cylinder attached to an underside of the end cap.
13. The simulated abdominal cavity as recited in Claim 1, wherein a bottom end of the piston is open to an outside of the cylinder.
14. The simulated abdominal cavity as recited in Claim 1, wherein the piston cyclically moves between a maximum volume position and a minimum volume positon based on a pre-programmed volume-pressure curve stored within a software architecture.
15. The simulated abdominal cavity as recited in Claim 14, wherein pressure and volume within the cylinder is controlled by the software architecture wherein a first sub system includes a graphical user interface (GUI) used to receive inputs from a user and display data, and a second sub- system having a script to facilitate a feedback loop and controls of the actuator.
16. The simulated abdominal cavity as recited in Claim 15, wherein the feedback loop includes: pressure data from the pressure transducer; pressure data from a breathing spike; and
Proportional, Integral, Derivative (PID) control to change a damping coefficient and a spring constant of the piston modeling equation ms + bi + kx = f where, where m is mass, b is the damping coefficient, k is the spring constant, x is the position of the mass, and f is the input force in order to match a spring constant of a subject abdominal wall.
17. The simulated abdominal cavity as recited in Claim 15, wherein the first sub system is further configured to create and operate the GUI and establish and send data through a serial connection with the second subsystem.
18. The simulated abdominal cavity as recited in Claim 15, wherein the second sub system is responsible for serial data from the GUI, reading pressure from the pressure transducer, calculating a required volume corresponding to the read pressure, commanding the actuator to move, and relaying pressure and volume data back to the GUI.
19. The simulated abdominal cavity as recited in Claim 18, wherein the required volume is based on pres sure- volume curve having both linear and non-linear regions.
20. The simulated abdominal cavity as recited in Claim 1, wherein the maximum volume position of the piston is above a bottom end of the cylinder.
PCT/US2021/028813 2020-04-23 2021-04-23 Simulated abdominal cavity for laparoscopic surgery WO2021216981A1 (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114010286A (en) * 2022-01-05 2022-02-08 南京利昂医疗设备制造有限公司 Pneumoperitoneum machine calibration device and method

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8469716B2 (en) 2010-04-19 2013-06-25 Covidien Lp Laparoscopic surgery simulator
US9087458B2 (en) 2013-03-15 2015-07-21 Smartummy Llc Dynamically-changeable abdominal simulator system
WO2015138982A1 (en) 2014-03-13 2015-09-17 Applied Medical Resources Corporation Advanced first entry model for surgical simulation
CN110464391A (en) * 2019-08-26 2019-11-19 浙江纳雄医疗器械有限公司 A kind of pneumoperitoneum apparatus calibrating installation

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8469716B2 (en) 2010-04-19 2013-06-25 Covidien Lp Laparoscopic surgery simulator
US9087458B2 (en) 2013-03-15 2015-07-21 Smartummy Llc Dynamically-changeable abdominal simulator system
WO2015138982A1 (en) 2014-03-13 2015-09-17 Applied Medical Resources Corporation Advanced first entry model for surgical simulation
CN110464391A (en) * 2019-08-26 2019-11-19 浙江纳雄医疗器械有限公司 A kind of pneumoperitoneum apparatus calibrating installation

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114010286A (en) * 2022-01-05 2022-02-08 南京利昂医疗设备制造有限公司 Pneumoperitoneum machine calibration device and method
CN114010286B (en) * 2022-01-05 2022-03-15 南京利昂医疗设备制造有限公司 Pneumoperitoneum machine calibration device and method

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