Insufflation stabilization system

Abstract

To provide pressure conditioning systems for supplying insufflation gas to an open-ended body conduit such as a rectal cavity during a transanal minimally invasive surgery (TAMIS) procedure can reduce billowing of walls of the body conduit.SOLUTION: A pressure conditioning system should include a pressure storage component, an accumulator, and a flow restrictor. The pressure storage component should include a variable volume reservoir that is biased to a relatively low volume state. The flow restrictor should include insufflation tubing with a restrictor plate having a relatively low diameter orifice. The pressure storage component, accumulator and flow restrictor can be fluidly connected together in various types of order in series or as side branches from a gas flow conduit. In spite of a pulsed or otherwise discontinuous insufflation gas flow and of leakage and absorption from the body conduit, the pressure conditioning system can maintain a constant pressure within the body conduit.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] This application relates to a pressure conditioning device for a surgical insufflation system, and in particular to a pressure conditioning device that maintains a substantially constant pressure at a surgical site despite pulsed or discontinuous insufflation delivery conditions, as well as leakage and absorption at the surgical site.

[0002] Description of Related Applications This application claims the benefit of U.S. Provisional Patent Application No. 62 / 327,941, entitled "INSUFFLATION STABILIZETION SYSTEM," filed April 26, 2016, and currently pending, and U.S. Provisional Patent Application No. 62 / 235,128, entitled "INSUFFLATION STABILIZETION SYSTEM," filed September 30, 2015, and currently pending, each of which is incorporated by reference in its entirety. [Background technology]

[0003] During transanal minimally invasive surgery (TAMIS), insufflation instruments are used to inflate the rectum with an insufflation gas, e.g., carbon dioxide (CO2). Inflation provides space for the surgeon to perform the surgical procedure using laparoscopic instruments and techniques. Most insufflation instruments deliver the CO2 in a pulsed manner, i.e., alternating pressure pulses with manometry. However, the colorectal system is not a sealed volume and the CO2 continuously leaks out of the inflated surgical field, causing a drop in pressure. In addition, CO2 is easily absorbed by the walls of the colorectal system, thereby exacerbating the pressure drop caused by leakage. CO2 can leak out of the system through various leak paths ranging from the length of the colorectal system, absorption by the intestinal / colorectal walls, and by the surgical instruments and tools used to gain access. At several points in the surgical procedure, smoke evacuation ports are permanently open to facilitate the flow of CO2, which expels smoke generated by electrocautery. Because of the many leak paths, pressure drops occur and the pulsating insufflation current appears as rippling of the rectal wall. The rippling occurs following pressure cycles from the insufflation instrument, i.e., the rectal wall expands when the insufflation instrument is providing CO2 pressure and contracts when the insufflation instrument is not providing pressure (pressure is being measured). Rectal wall movement can complicate laparoscopic surgery during TAMIS or other transanal procedures, which may require manipulation and treatment of growths on the rectal wall. Summary of the Invention

[0004] In various embodiments, the devices described herein can significantly reduce tissue ruffling in an open internal conduit, such as the rectal cavity, insufflated by a pulsed insufflation pump. Such devices can condition a pulsed or discontinuous insufflation gas flow to provide a substantially continuous insufflation gas flow that can have a flow rate that varies in response to pressure loss at the inlet from a zero pressure differential condition between pulses of the insufflation pump and backpressure reduction at the outlet due to leakage at the surgical site and absorption by tissue within the open internal conduit.

[0005] In one particular embodiment, a gas flow pressure conditioning device for a pulsed insufflation pump is provided. The device has a fluid inlet port, an outlet fluid conduit, and a reservoir. The fluid inlet port is configured to receive a flow of gas from the pulsed insufflation pump. The outlet fluid conduit is configured to provide a flow of insufflation gas to a surgical site. The reservoir is fluidly coupled to the inlet fluid port and the outlet fluid conduit. The inlet fluid port has a first inner diameter and the outlet fluid conduit has a second inner diameter greater than the first inner diameter.

[0006] In certain embodiments, an insufflation system is provided. The insufflation system includes a surgical site access port and a gas flow pressure conditioning device for a pulsed insufflation pump. The surgical site access port has a port surface, a first trocar, and a second trocar. The first trocar is positionable through the port surface. The first trocar has a first instrument channel extending therethrough. The second trocar is positionable through the port surface. The second trocar has a second instrument channel and an insufflation port extending therethrough. The gas flow pressure conditioning device has an inlet fluid conduit, an outlet fluid conduit, and a reservoir. The inlet fluid conduit is configured to receive a flow of gas from the pulsed insufflation pump. The outlet fluid conduit is configured to provide a flow of insufflation gas to the surgical site access port. The reservoir is fluidly coupled to the inlet fluid conduit and the outlet fluid conduit. The inlet fluid conduit has a first inner diameter and the outlet fluid conduit has a second inner diameter that is larger than the first inner diameter.

[0007] In one particular embodiment, a gas flow pressure conditioning apparatus for a pulsed insufflation pump is provided. The apparatus has an inlet port, an accumulator, a pressure storage vessel, a flow restrictor, and an outlet port. The inlet port is configured to receive a flow of gas from the pulsed insufflation pump. The accumulator is fluidly coupled to the inlet port. The pressure storage vessel is fluidly coupled to the inlet port. The flow restrictor is fluidly coupled to the inlet port. The outlet port is fluidly coupled to the inlet port and disposed downstream of the accumulator, the pressure storage vessel, and the flow restrictor.

[0008] In certain embodiments, an insufflation system for maintaining a substantially constant pressure at a surgical site is provided. The insufflation system includes a pulsed insufflation pump and a pressure conditioning device. The pulsed insufflation pump includes a pump outlet. The pressure conditioning device has an inlet, a pressure storage container, a reservoir, a flow restrictor, and an outlet port.

[0009] In one particular embodiment, a surgical site closure device for sealing an open body conduit is provided. The sealing device includes an elastomeric bag. The elastomeric bag has an open end and a closed end opposite the open end. The elastomeric bag is sized and shaped to be positioned within the body conduit. The elastomeric bag has an insertion configuration that allows the elastomeric bag to be advanced unobstructed within the body conduit. The elastomeric bag is inflatable to an insufflation state that causes the elastomeric bag to expand the body conduit.

[0010] In one particular embodiment, a surgical site closure device for sealing an open body conduit is provided. The sealing device includes an inflatable member and an inflation tube. The inflatable member has a deflated state dimensioned to be advanced through an open end of the body conduit. The inflatable member is inflatable with a fluid to an inflated state dimensioned to seal against a wall of the body conduit. The inflation tube includes a lumen extending from a proximal end to a distal end and extending between the proximal and distal ends, the distal end of the inflation tube is coupled to the inflatable member, and the lumen is fluidly coupled to the inflatable member to provide fluid to the inflatable member.

[0011] In certain embodiments, a surgical site sealing device for sealing an open body conduit is provided, the sealing device having a diaphragm and a flexible ring disposed about the diaphragm, the flexible ring being configurable into a first configuration in which the flexible ring is advanceable through the body conduit and a second configuration in which the flexible ring is configurable against a wall of the body conduit.

[0012] In certain embodiments, an insufflation system is provided that maintains a substantially constant pressure at a surgical site. The insufflation system includes a reservoir. The reservoir has an insufflation chamber, a pressurized chamber, and a separation member. The insufflation chamber has an inlet port and an outlet port fluidly connectable to an insufflation pump. The pressurized chamber has a pressurization port and a pressure relief valve connectable to a source of pressurized fluid. The separation member fluidly isolates the insufflation chamber from the pressurized chamber. The separation member is movable in response to an insufflation pressure in the insufflation chamber and a pressurization pressure in the pressurized chamber.

[0013] In certain embodiments, an insufflation system is provided that maintains a substantially constant pressure at a surgical site. The insufflation system includes a reservoir and a pressure control system. The reservoir has an insufflation chamber and a piston. The insufflation chamber has an inlet port and an outlet port fluidly coupled to an insufflation pump. The piston is slidable within the reservoir to define a volume of the insufflation chamber. The pressure control system includes a flow sensor fluidly coupled to the inlet port, a pressure sensor fluidly coupled to the outlet port, a linear actuator, and a programmable logic controller. The linear actuator is operatively coupled to the piston. The linear actuator has a position feedback sensor. The programmable logic controller is electrically coupled to the flow sensor, the pressure sensor, the linear actuator, and the position feedback sensor. The programmable logic controller is configured to operate the linear actuator to position the piston in the reservoir at a position that maintains a desired pressure at the outlet port in response to electrical signals from the flow sensor and the pressure sensor. [Brief description of the drawings]

[0014] [Figure 1] FIG. 2 is a side view of one embodiment of a gas flow pressure conditioning apparatus. [Diagram 2] 2 is a schematic diagram of an embodiment of the pressure conditioning device of FIG. 1 used in a surgical site access system. [Diagram 3] 2 is a schematic diagram of one embodiment of a surgical site access system including the pressure conditioning device of FIG. 1. [Figure 3A] 1 is a schematic diagram of another embodiment of a pressure conditioning device for a surgical site access system. [Figure 4] 2 is a perspective view of the pressure conditioning device of FIG. 1 in an expanded configuration on a test fixture with a simulated body conduit. [Diagram 5] FIG. 2 is a side view of another embodiment of a gas flow pressure conditioning apparatus. [Figure 6]FIG. 2 is a side view of another embodiment of a gas flow pressure conditioning apparatus. [Figure 7] FIG. 1 is a perspective view of one embodiment of a gas flow pressure conditioning apparatus. [Figure 8] FIG. 8 is a front view of the pressure conditioning device of FIG. 7. [Figure 9] FIG. 8 is a side view of the pressure conditioning device of FIG. 7. [Figure 10] FIG. 13 is a side view of another embodiment of a gas flow pressure conditioning device on a test fixture. [Figure 11] 11 is a schematic diagram of the gas flow pressure conditioning device of FIG. 10. [Figure 12] FIG. 13 is a side view of another embodiment of a gas flow pressure conditioning device on a test fixture. [Figure 13] FIG. 13 is a side view of another embodiment of a gas flow pressure conditioning device on a test fixture. [Figure 14] FIG. 2 is a perspective view of one embodiment of a pressure storage component for a pressure conditioning device. [Figure 15] FIG. 2 is a perspective view of another embodiment of a pressure storage component for a pressure conditioning device. [Figure 16] FIG. 2 is a perspective view of another embodiment of a pressure storage component for a pressure conditioning device. [Figure 17] FIG. 13 is a side view of another embodiment of a gas flow pressure conditioning device on a test fixture. [Figure 18A] 1 is a schematic diagram of one embodiment of an insufflation system. [Figure 18B] 1 is a schematic diagram of another embodiment of an insufflation system including a flow restrictor orifice. [Figure 18C] 1 is a schematic diagram of another embodiment of an insufflation system including a side branch attenuator. [Figure 18D] 1 is a schematic diagram of another embodiment of an insufflation system including a Helmholtz resonator. [Figure 19A] 1 is a schematic diagram of one embodiment of a surgical insufflation system including a gas flow pressure conditioning device. [Figure 19B] 1 is a schematic diagram of another embodiment of a surgical insufflation system including a gas flow pressure conditioning device. [Figure 19C] 1 is a schematic diagram of another embodiment of a surgical insufflation system including a gas flow pressure conditioning device. [Figure 19D] 1 is a schematic diagram of another embodiment of a surgical insufflation system including a gas flow pressure conditioning device. [Figure 19E] 1 is a schematic diagram of another embodiment of a surgical insufflation system including a gas flow pressure conditioning device. [Figure 19F] 1 is a schematic diagram of another embodiment of a surgical insufflation system including a gas flow pressure conditioning device. [Figure 20] FIG. 1 is a graphical representation of surgical site pressure over time for a simulated surgical access site insufflated with a pulsatile insufflation pump. [Figure 21] FIG. 1 is a graphical illustration of surgical site pressure over time for a simulated surgical access site insufflated with one embodiment of a pulsatile insufflation pump and pressure conditioning device. [Figure 22] FIG. 13 is a graphical illustration of surgical site pressure over time for a simulated surgical access site insufflated with another embodiment of the pulsatile insufflation pump and pressure conditioning device. [Figure 23] FIG. 13 is a graphical illustration of surgical site pressure over time for a simulated surgical access site insufflated with another embodiment of the pulsatile insufflation pump and pressure conditioning device. [Figure 24] FIG. 13 is a graphical illustration of surgical site pressure over time for a simulated surgical access site insufflated with another embodiment of the pulsatile insufflation pump and pressure conditioning device. [Diagram 25] FIG. 1 is a graphical representation of surgical site pressure over time for a simulated surgical access site in a cadaveric laboratory apparatus insufflated with a pulsatile insufflation pump. [Figure 26] FIG. 26 is a graphical depiction of surgical site pressure over time for the simulated surgical access site of FIG. 25 insufflated with one embodiment of a pulsatile insufflation pump and pressure conditioning device. [Figure 27]FIG. 1 is a graphical illustration of surgical site pressure over time for a simulated surgical access site insufflated with one embodiment of a pulsatile insufflation pump and pressure conditioning device. [Figure 28] FIG. 13 is a graphical illustration of surgical site pressure over time for a simulated surgical access site insufflated with another embodiment of the pulsatile insufflation pump and pressure conditioning device. [Figure 29] FIG. 13 is a graphical illustration of surgical site pressure over time for a simulated surgical access site insufflated with another embodiment of the pulsatile insufflation pump and pressure conditioning device. [Diagram 30] FIG. 13 is a graphical illustration of surgical site pressure over time for a simulated surgical access site insufflated with another embodiment of the pulsatile insufflation pump and pressure conditioning device. [Diagram 31] 1 is a schematic diagram of one embodiment of an insufflation system. [Diagram 32] 1 is a schematic diagram of another embodiment of an insufflation system. [Diagram 33] 1 is a schematic diagram of another embodiment of an insufflation system. [Figure 34A] 1 is a perspective view of one embodiment of a body conduit sealing device. [Figure 34B] 1 is a perspective view of another embodiment of a body conduit sealing device. [Figure 34C] 1 is a perspective view of another embodiment of a body conduit sealing device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] In various embodiments, a gas insufflation pressure conditioning device can be fluidly coupled to the pulsed insufflation device to reduce undulation of the body conduit and reduce or eliminate rectal wall movement when the pulsed insufflation device is used in a TAMIS procedure. The pressure conditioning device can be configured to maintain a substantially constant pressure and flow within the body conduit despite leakage and absorption from the body conduit at the surgical site and pulsed insufflation gas flow distribution. Additionally, undulation can be further reduced by the provision of a body conduit sealing or closure device to create an enclosed volume within the rectal cavity to minimize pressure loss while eliminating rectal wall movement.

[0016] 1-4, there is shown one embodiment of an insufflation gas pressure conditioning device 70. In the illustrated embodiment, the pressure conditioning device 70 has a gas flow path extending from a segment of an inlet gas tube 92, through an elastomeric film pouch, to a segment of an outlet gas tube 94. Advantageously, the elastomeric film pouch provides the pressure conditioning functions of a pressure reservoir, insufflation gas volume buildup, and flow restriction to maintain a substantially constant insufflation gas flow at the surgical site despite discontinuous pulsatile flow from the insufflator.

[0017] 1, the film pouch 86 may be formed from a sheet of polymeric film that is folded back on itself and welded to form an enclosed volume while contouring an edge 88. In the illustrated embodiment, when the pouch 86 is in a deflated state, the pouch has a generally rectangular shape with a relatively long width and a relatively short height. In other embodiments, it is contemplated that the pouch may be formed into other shapes that achieve desired product packaging, aesthetic, or gas flow considerations.

[0018] 1, an inlet port 82 and an outlet port 84 may be additionally provided in the film pouch 86 to provide a gas flow path through the pouch. In the illustrated embodiment, the inlet port 82 and the outlet port 84 are located on opposite sides of the pouch 86 to provide a relatively direct flow path along the longitudinal axis of the width of the pouch 86. In other embodiments, it is contemplated that other locations for the inlet port 82 and the outlet port 84 may be used to vary the gas flow characteristics of the pressure conditioning device. For example, in some embodiments, the inlet port 82 and the outlet port 84 may be adjacent to one another along one edge or on opposite edges relative to the height of the pouch 86, such that the pressure conditioning device may have attributes of a side branch attenuator (schematically shown in FIG. 18C).

[0019] In the illustrated embodiment, the inlet port 82 and the outlet port 84 may each comprise a bag port with a barbed fitting, such as is commercially available from Value Plastics, Inc. The pressure conditioning device may further comprise a segment of inlet tubing 92 coupled to the barbed fitting of the inlet port 82 and a segment of outlet tubing 94 coupled to the barbed fitting of the outlet port 84. In some embodiments, the outlet port 84 may be directly coupled to an insufflation tube. In other embodiments, the outlet pouch 84 and the outlet tube 94 may be formed as a single component. The inlet tube 92 may have an attachment end configured to be coupled to an insufflator or an insufflation tube from an insufflator. The outer tube 94 may have an attachment end configured to be coupled to an insufflation tube that is fluidly coupled to a surgical access port.

[0020] While the illustrated embodiment has both an inlet tube 92 and an outlet tube 94, in certain embodiments, it may be desirable for the pressure conditioning device to have only one tube or be provided with only a port. For example, in some embodiments, the pressure conditioning device may have an inlet port 82 located at the upstream end and an outlet tube 94 located at the downstream end. Thus, a desired length of inlet tube can be associated with an insufflator. In other embodiments, the pressure conditioning device may have an inlet port 82 located at the upstream end and an outlet port 84 located at the downstream end, such that the inlet and outlet tubes can be associated with an insufflator and a surgical access port. Additionally, in some embodiments, one or both of the inlet and outlet ports may have a luer fitting rather than a barbed fitting, such that at least one of the inlet and outlet ports has a luer port. In some embodiments, at least one of the inlet and outlet ports may be heat sealed to the pouch. 3A shows an embodiment of a pressure conditioning device 70 having a film pouch 86 with an inlet port 82' having a Luer fitting and an outlet port 84' connected to a length of outlet tube 94' that is connected to an insufflation trocar 940. In the embodiment shown, the outlet tube 94' is a segment of corrugated tubing that may be desirable in an insufflation system to reduce the risk of tubing kinking and associated fluid flow disturbances.

[0021] The pouch 86 may be sized and shaped to provide the pressure conditioning aspects of the separate pressure storage components and accumulators of other embodiments of the pressure conditioning devices described herein. For example, in some embodiments, the pouch may be formed of a polymeric material with a predetermined thickness and elasticity to provide the desired pressure storage. In some embodiments, the pouch 86 may be formed of a polyurethane film that can stretch in response to insufflation pressure. In other embodiments, it is contemplated that other film materials and / or thicknesses may be used in the pressure conditioning device to achieve the desired pressure storage.

[0022] The pouch 86 can be sized to stabilize the volume of the open body conduit at the surgical site where the pulsed insufflation flow is delivered. As further described with reference to Figures 2, 3, and 20-30, in some embodiments, the pouch 86 can be sized to provide a desired pressure conditioning profile for a TAMIS procedure. Desirably, in certain embodiments, the pouch 86 can have a volume of at least about 6.5 liters. In other embodiments, the pouch 86 can have a volume of about 6.5 liters to about 8 liters. In one embodiment, the pouch 86 can have a volume of about 7.4 liters. If the pouch has an undesirably small pouch volume for the surgical site, there may be insufficient pressure storage and accumulation capacity to condition the insufflation pump pulse cycle. If the pouch is undesirably large for the surgical site, insufflation delay times may occur because the insufflator pulse cycle may be subject to pressure fluctuations at the relatively large pouch volume rather than at the surgical site. It is contemplated that pouches may be constructed with pouch volumes different from the ranges noted above for use with patients having particularly small or particularly large colorectal volumes. Similarly, it is contemplated that pouches may have different pouch volumes if it is desired to use pressure conditioning device 70 to condition insufflation pressure pulses at different surgical sites.

[0023] Referring to Figure 2, the pressure conditioning apparatus of Figure 1 is shown diagrammatically. The pressure conditioning apparatus 70 includes an elastomeric film pouch or bag 86 that may have an inlet port 82 and an outlet port 84 that define a gas flow path through the pouch. The pressure conditioning apparatus may further include an inlet fluid conduit, such as an inlet gas tube 92, and an outlet fluid conduit, such as an outlet gas tube 94. The inlet gas tube 92 may include a fitting or coupling that is fluidly coupled to an insufflation pump.

[0024] 2, in some embodiments, the inlet gas tube 92 and the outlet gas tube 94 can be sized relative to one another to provide a desired pressure conditioning distribution. For example, in the illustrated embodiment, the inlet tube 92 can have a first inner diameter and the outlet tube 94 can have a second inner diameter that is larger than the first inner diameter.

[0025] 2 and 3, in some embodiments, the pressure conditioning device 70 described herein can be provided within a surgical site access system 900, such as a surgical access port 902 having an artificial body wall configured with a port surface 904, such as the gel surface of surgical access ports commercially available under the trademarks GELPORT and GELPOINT. In certain embodiments, the pressure conditioning device 70 described herein can be included within a surgical site access system configured for use in a natural orifice entry surgical procedure, such as a surgical access port commercially available as the GELPOINT pathway system. Certain aspects of the GELPOINT pathway system are described in U.S. Patent Nos. 9,289,115 and 9,289,200, each of which issued on March 22, 2016, and each of which is entitled "NATURAL ORIFICE SURGERY SYSTEM," and each of which is incorporated herein by reference in its entirety. In general, the surgical site access system 900 may include a pressure conditioning device 70, a surgical access port 902 having a port surface 904, and a number of trocars 930, 940 configured to be advanced through the port surface 904 to closely contact a surgical instrument inserted therethrough.

[0026] 3, in some embodiments, the surgical access port 902 can include at least one insufflation port 910, 920. In some embodiments of the surgical site access system 900, the pressure conditioning device 70 can be fluidly coupled to one of the insufflation ports 910, 920. The other of the insufflation ports 910, 920, in this case, can be left free and held closed with a stopcock valve or other closure device, can be coupled to another gas source, or can be selectively opened to allow smoke evacuation for the electrosurgical procedure.

[0027] 3 , in some embodiments, the surgical site access system 900 can further include an insufflation trocar 940. The pressure conditioning apparatus 70 can be fluidly coupled to the insufflation trocar 940, and the trocar 940 can be advanced through the artificial body wall 904 to provide an insufflation gas flow to the surgical site. The insufflation trocar 940 can include an instrument access channel 942 and an insufflation port 944. In certain embodiments, the insufflation port 944 of the insufflation trocar 940 can have a relatively large diameter relative to the insufflation ports 910, 920 of the surgical access port 902. In some embodiments, the insufflation port 944 of the insufflation trocar 940 can include a barbed fitting that receives the outlet gas tube 94 of the pressure conditioning apparatus 70. Thus, the insufflation trocar 940 desirably accommodates the insufflation gas flow rate of a pressure conditioning device 70 having a relatively large inner diameter, such as a fluid coupling, such as the outlet tube 94, of the embodiment of FIG.

[0028] The pressure conditioning device 70 may be sized and shaped to provide a desired pressure conditioning distribution at the surgical site at the open internal body conduit. For example, it may be desirable for the pressure conditioning device to provide an insufflation gas flow with a relatively small delay time and a relatively small pressure variation. The delay time represents the time delay between the actuation of an insufflation pump fluidly coupled to the surgical site access system and achieving the desired insufflation pressure at the surgical site. The pressure variation represents the pressure difference between high and low pressure peaks when the insufflation pressure at the surgical site is plotted over time. Additionally, it may be desirable for the pressure conditioning device to be relatively compact so that it does not require a significant amount of operating room space.

[0029] 4, the insufflation gas pressure conditioning device 70 of FIG. 1 is shown coupled to a test fixture including a simulated internal conduit 180 in an expanded state. The pressure conditioning device 70 is shown with the pouch 86 in an inflated state and with the gas flow path (arrows indicating flow direction) from the inlet tube segment 92, through the pouch 86, through the outlet tube segment 94, and to the simulated internal conduit 180. Desirably, the simulated internal conduit 180 can be used to evaluate the conditioned pressure distribution performance of various pressure conditioning device 70 film pouch materials, thicknesses, volumes, and geometries, as will be further described with reference to FIGS. 20-30.

[0030] Referring to FIG. 5, another embodiment of the pressure conditioning device 70 is shown. In the illustrated embodiment, a film pouch, for example of FIGS. 1-4, may be contained within an outer envelope 71. The outer envelope 71 may be sized to allow the pressure conditioning device 70 to achieve a predetermined amount of elastic and / or plastic deformation of the film pouch, while preventing the film pouch and its associated seams from plastically deforming to a material yielding or tearing seam condition. Thus, insufflation gas flows from the inlet pipe segment 92, through the pressure conditioning device 70, and through the outlet pipe segment 94. As the pressure conditioning device 70 inflates and expands, it may abut against the inner surface of the outer envelope 71, thereby reducing or stopping further expansion.

[0031] In some embodiments, the outer envelope 71 may have the same film material and thickness as the film pouch of the pressure conditioning device 70. In other embodiments, it may be desirable for the outer envelope to be made of a different polymeric film material or a different thickness of the same material. For example, in some embodiments, the film pouch may be made of a polyurethane film having a thickness of 0.003 inches (0.076 mm) and the outer pressure envelope may be made of a polyurethane film having a thickness of 0.006 inches (0.152 mm).

[0032] Referring to FIG. 6, another embodiment of the pressure conditioning device 70 is shown. In the illustrated embodiment, the film pouch of the pressure conditioning device is disposed within an outer sleeve 73. The outer pressure sleeve may have a generally tubular profile with open ends through which the film pouch of the pressure conditioning device 70 extends. As in the embodiment of FIG. 5, the outer pressure sleeve may allow the pressure conditioning device 70 to achieve a predetermined amount of elastic and plastic deformation when pressurized with an insufflation gas flow, while limiting plastic deformation to prevent material yielding or seal tearing. The outer sleeve 73 may be joined to the film pouch of the pressure conditioning device 70, for example, by being heat welded along a seam of the film pouch. In the illustrated embodiment, the outer sleeve 73 is joined to the film pouch along one seam of the film pouch. In other embodiments, the outer sleeve may be joined at two or more seams of the film pouch or may be joined elsewhere to the film pouch with a welded seam or with an adhesive.

[0033] 7-9, perspective, front, and side views of another embodiment of a gas flow pressure conditioning device 10 are shown. In the embodiment of FIGS. 7-9, the various pressure conditioning functions of pressure storage, volumetric accumulation, and flow restriction can each be performed by a dedicated component. In the illustrated embodiment, the pressure conditioning device 10 has a housing 12 that encloses or substantially encloses the components of the device 10. The housing 12 can be sized and shaped to fit on an equipment cart or rack used in medical procedures. A fluid flow inlet port 20 and an outlet port 60 can protrude from or be recessed into the housing 12. During a surgical procedure, the inlet port 20 can be fluidly coupled to an insufflation source, such as a pulsed insufflation pump. The pulsed insufflation pump can provide fluid flow in a discontinuous or pulsed flow. The exit port 60 may be fluidly coupled to a surgical access port, such as an insufflation channel provided in a trocar cannula, a single-site minimally invasive surgical access port, or a natural orifice or transanal minimally invasive surgical access port.

[0034] With continued reference to FIGS. 7-9, in some embodiments, the housing 12 of the pressure conditioning device 10 houses the pressure storage component 30 and the accumulator 50. In some embodiments, the housing 12 can have interior walls that form separate compartments for each of the pressure storage component 30 and the accumulator 50. The pressure storage component 30 and the accumulator 50 can be fluidly coupled to each other and to the inlet port 20 and the outlet port 60, thereby forming a fluid flow path between the inlet port 20 and the outlet port 60. For example, a segment of gas flow tube 45 can fluidly couple the pressure storage component 30 to the accumulator 50. As will be further described with reference to FIGS. 18A-18D, in some embodiments, this segment of gas flow tube 45 can be fluidly coupled to a flow restrictor, which further conditions the gas flow therethrough. The flow restrictor can be configured to reduce the amplitude of the pulses produced by the insufflator while increasing the duration of the pulses. Thus, the flow restrictor can condition the pulsed insufflation gas flow to near continuous flow downstream of the flow restrictor.

[0035] 7-9, in the illustrated embodiment, the pressure storage component 30 is located downstream of the inlet port 20, the gas flow tube 45 is located downstream of the pressure storage component, the accumulator 50 is located downstream of the gas flow tube 45, and the outlet 60 is located downstream of the accumulator 50. It is contemplated that other arrangements of these components may be used in other embodiments. For example, in some embodiments, the pressure conditioning device 10 may have an accumulator located upstream of the pressure storage component and the pressure storage component located upstream of the flow restrictor relative to the fluid flow path. In other embodiments, the pressure conditioning device 10 may have a flow restrictor located upstream of the pressure storage component and the pressure storage component located upstream of the accumulator relative to the fluid flow path.

[0036] Further, in the illustrated embodiment, the pressure storage component 30, gas flow tube 45, and accumulator 50 are fluidly coupled in series between the inlet port 20 and the outlet port 60. In other embodiments, it is envisioned that various arrangements of parallel or side branch fluid couplings may be incorporated into the pressure conditioning device.

[0037] The pressure storage component is capable of receiving, storing, and returning pressurized insufflation gas, e.g., CO2, such that the returned CO2 is at substantially the same pressure as the received CO2. In addition, the pressure storage component desirably may return pressurized CO2 relatively quickly. For example, in some embodiments, the pressure storage component is desirably configured to maintain the pressure of the insufflation gas flow upon cessation of the insufflation pulse or relief of back pressure from the surgical site for less than about 10% of the time that the pulsed insufflator is in a pressurization cycle. Advantageously, the pressure storage component 30, in conjunction with the pressure conditioning device 10, may be configured to rapidly vary the flow rate of insufflation gas at the outlet port 60 to counteract leakage and absorption of CO2 at the surgical site downstream of the outlet. Thus, the pressure conditioning device 10 may maintain a substantially constant pressure at the surgical site.

[0038] As shown, the pressure storage component 30 includes a container 32 or fluid reservoir and a pressure generating mechanism. The container 32 may be a flexible or elastomeric container having a variable internal volume determined by flexing or expansion of the container walls between a first relatively low volume state and a second relatively high volume state. The pressure generating mechanism may bias the container 32 toward the first relatively low volume configuration against an outer wall of the container 32, thereby maintaining a desired gas pressure within the container 32 even when gas flow at the inlet 20 is interrupted (e.g., between pressurization pulses from a pulsed insufflation pump) or back pressure from the outlet 60 is reduced (e.g., when insufflation gas escapes from or is absorbed by tissue at the surgical site).

[0039] 7-9, the pressure generating mechanism may include a first plate 34 abutting the wall of the container 32, a second plate 36 abutting the housing 12, and a biasing mechanism, such as one or more coil springs 38, disposed between the first plate 34 and the second plate 36 to generate a biasing force tending to separate the plates and compress the container 32. In the illustrated embodiment, the plates 34, 36 are generally rectangular and the biasing mechanism includes four coil springs 38 extending between the first plate 34 and the second plate 36 adjacent corresponding corners of the generally rectangular plates. It is contemplated that in other embodiments, more than four or less than three coil springs 38 may be disposed at various locations between the plates 34, 36.

[0040] The plates 34, 36 and the housing 12 may each have engagement surfaces for aligning the plates in a desired orientation within the housing to generate a biasing force in a desired direction relative to the housing 12 and receptacle 32. For example, in the illustrated embodiment, the plates 34, 36 each have a number of recesses or grooves positioned to engage and slide along inwardly protruding ribs provided within the housing 12.

[0041] In some embodiments, the pressure storage component 30 may include a pressure adjustment mechanism, such as one or more threaded spacers 40, that allows a user to adjust the position of the second plate 36 relative to the housing 12. The threaded spacer 40 may be advanced to position the second plate 36 relatively deep within the housing, thereby applying a relatively high biasing force generated by the pressure-generating mechanism to the container 32. Alternatively, the threaded spacer 40 may be retracted to position the second plate 36 relatively closer to the top surface of the housing, thereby applying a relatively low biasing force generated by the pressure-generating mechanism to the container 32. In the illustrated embodiment, the threaded spacers 40 each have a threaded shaft with a proximal end provided with an adjustment knob and a distal end positioned against the second plate 36. The threaded shaft fits into a corresponding threaded aperture formed in the top surface of the housing 12.

[0042] 7-9, as insufflation gas flows downstream from pressure storage component 30, it flows through gas flow tube 45, whose flow restrictor further conditions the pulsed distribution of the insufflation gas flow, and into accumulator 50. Accumulator 50 can provide a reservoir of insufflation gas that is pressurized by pressure storage component 30 and can stabilize the pressure at a surgical site that is fluidly coupled to outlet port 60 between insufflator pulses.

[0043] In certain embodiments, the accumulator 50 may comprise a flexible or rigid container or reservoir. The accumulator 50 may be sized with a volume capable of maintaining a predetermined percentage of the insufflation pump's volume rating such that the system maintains a substantially constant pressure at the surgical site. For example, the accumulator may desirably have a volume that accommodates approximately 10% to 20% of the insufflator's volume rating. Preferably, the accumulator may have a volume that accommodates approximately 15% of the insufflator's volume rating.

[0044] Referring to Figure 10, a side view of another embodiment of an insufflation gas pressure conditioning apparatus 110 is shown. In the illustrated embodiment, the conditioning apparatus 110 has a gas flow path extending from an inlet port 120 to an outlet port 160, which is shown fluidly coupled to a simulated body conduit 180 in an expanded state in a test apparatus. The inlet port 120 is fluidly coupled to a gas conduit 170. The pressure conditioning apparatus 110 includes a pressure storage component 130, a flow restrictor gas tube 145, and an accumulator 150 fluidly coupled to the gas conduit 170. The various components of the pressure conditioning apparatus 110 operate substantially as described above with reference to the pressure conditioning apparatus of Figures 7-9.

[0045] With continued reference to FIG. 10, in the illustrated embodiment, the pressure storage component 130 comprises a container with a bellows configuration. The bellows is expandable in response to gas pressure, but is biased to a relatively low volume contracted configuration. In the illustrated embodiment, the accumulator 150 comprises a pouch having a predetermined volume. The pouch may be formed of a film of a polymeric material, such as a polyurethane film. The pressure storage component 130, gas tube 145, and accumulator 150 may be housed within a housing 112 similar to the housing of the embodiment of FIGS. 7-9.

[0046] Referring to Figure 11, a schematic diagram of the pressure conditioning device of Figures 10 and 12 is shown. As shown, pressure storage component 130 extends from a side branch of gas conduit 170, which extends from inlet port 120 to outlet port 160. Thus, in various embodiments of the pressure conditioning device described herein, these components can be arranged in a variety of flow configurations, including in series and side branch configurations, to maintain a desired pressure distribution at the surgical site.

[0047] Referring to Figure 12, a side view of another embodiment of a gas flow pressure conditioning apparatus 210 is shown. The apparatus of Figure 12 is substantially identical to the apparatus of Figure 10, with a housing 212 containing a pressure storage component 230 and an accumulator 250. A gas flow conduit 270 can fluidly couple the pressure storage component 230 and the accumulator 250 to the inlet port 220 and the outlet port 260. In the illustrated embodiment, the housing 212 is dimensioned to have a reduced height footprint compared to the housing 112 of the embodiment of Figure 10. Thus, the materials, volumes, and biasing characteristics of the pressure storage component 230 and the accumulator 250 can be selected to maintain a desired insufflation pressure distribution.

[0048] Referring to Figure 13, a side view of another embodiment of a gas flow pressure conditioning apparatus is shown. The apparatus of Figure 13 is substantially identical to the apparatus of Figures 10 and 12, except that the pressure storage component 330 and accumulator 350 are not disposed within a housing. A gas flow conduit 370 can fluidly couple the bellows profiled pressure storage component 330 and accumulator 350 to an inlet port and an outlet port coupled to the simulated body conduit 180.

[0049] 14-16, various embodiments of the pressure storage component 430, 530, 630 are shown. For each of the illustrated embodiments, the pressure storage component 430, 530, 630 can include a reservoir or container 432, 532, 632. The reservoir 432, 532, 632 can have a variable volume, and a pressure generating mechanism can bias the reservoir 432, 532, 632 to a relatively low volume state.

[0050] 14, the illustrated pressure storage component 430 includes a polymer pouch reservoir 432 having a compression sleeve 438 surrounding a portion of the polymer pouch reservoir 432. The compression sleeve 438 is comprised of a resilient mesh that biases the reservoir 432 into a relatively low volume configuration to store and return pressure from the port 420 of the pressure storage component 430.

[0051] 15, the illustrated pressure storage component 530 can include a reservoir 532 sandwiched between compression members or plates 534, 536 that are biased toward one another to compress the reservoir 532 toward a relatively low volume configuration. The plates 534, 536 are biased toward one another by one or more compression bands 538. The pressure storage component 530 can include a single fluid port 520 that is fluidly coupled to a pressure conditioning device as a side branch. In some embodiments, the pressure storage component 530 can further include a second port such that the reservoir 532 can have an inlet port and an outlet port.

[0052] 16, the illustrated pressure storage component 630 may include a reservoir 632 contained within a housing or canister 612. A compression plate 636 may abut the wall of the reservoir 632 to press the reservoir against the inner wall of the canister 612. The compression plate 636 may be coupled to the canister 612 by a coil spring 638. The position of the compression plate 636 relative to the housing, and thus the biasing force it creates, is adjustable by an adjustment mechanism, such as a threaded shaft 640. In some embodiments, the pressure storage component 630 may be configured with an inlet port 620 and an outlet port 660 in series that are fluidly connectable within the pressure conditioning device.

[0053] Referring to Figure 17, a side view of another embodiment of a gas flow pressure conditioning device is shown. The device of Figure 17 is substantially identical to the device of Figure 13, but does not include a housing containing the pressure storage component 430 and accumulator 450. A gas flow conduit 470 can fluidly couple the pressure storage component 430 and accumulator 450 to the inlet port 420 and an outlet port 460 that is coupled to the simulated body conduit 180. The pressure storage component 430 consists of a polymeric film pouch that is compressed by an expandable mesh as will be further described with reference to Figure 14.

[0054] 18A-18D, various embodiments 750, 760, 770 of flow restrictors for pressure conditioning devices described herein are shown in schematic form. As described above with reference to FIGS. 7-9, in some embodiments, the flow restrictor may be coupled in series between the pressure storage component and the device in the pressure conditioning device. Many insufflation pumps provide a pulsed output having pressure pulses defined by amplitude and duration. One or more flow restrictors arranged in series or as side branches (FIGS. 18C, 18D) in a gas conduit 740 or tube (FIG. 18B) may condition the pulsed output to reduce the amplitude and increase the duration of the pulse downstream of the flow restrictor. Thus, the pressure conditioning devices described herein may include a flow restrictor that may further condition the gas flow therethrough to maintain a substantially constant pressure at the output of the device despite the pulsed inflow. In some embodiments, the flow restrictor 750 comprises a flow restrictor plate 750 with a relatively small orifice 755 in a relatively large gas conduit or tube 745 (FIG. 18B). In other embodiments, the flow restrictor 760 comprises a side branch attenuator comprising a canister or tube 762 having a restrictor plate 765 with a relatively small orifice (FIG. 18C). The side branch attenuator tube 762 is fluidly coupled to the side branch of the flow conduit. In other embodiments, the flow restrictor 770 may comprise a Helmholtz resonator having multiple restrictor plates 774 with relatively small orifices in a tube 772 or canister that is fluidly coupled to the side branch of the flow conduit.

[0055] 19A-19F, in various embodiments, a pressure conditioning device 810 as described herein can be fluidly coupled to an insufflation pump 800 and to an open intracorporeal conduit, such as the patient's rectum 820, to form a surgical system configured to maintain a desired insufflation pressure profile. Although FIGS. 19A-19F label pressure conditioning device 810 as a "BAG," it is envisioned that the embodiment of the surgical system illustrated generally herein can incorporate the pouch-utilizing pressure conditioning device described with reference to FIGS. 1-4, any of the various other embodiments of pressure conditioning devices described herein, or another pressure conditioning device configured to maintain a desired insufflation pressure profile.

[0056] 19A, the illustrated embodiment of a surgical system includes a pressure conditioning device 810 fluidly coupled to an insufflation pump 800 by a first fluid coupling 830 and to a body conduit by a second fluid coupling 840. The arrow heads indicate generally the direction of fluid flow within the surgical system. In some embodiments, the first fluid coupling 830 and the second fluid coupling 840 may each comprise a segment of gas flow tubing, such as that shown in FIG. 4. In some embodiments, the second fluid coupling 840 may be coupled to the body conduit directly at a surgical access port, such as the insufflation port of a cannula or through an artificial body wall defined by a gel surface of surgical access ports commercially available under the trademarks GELPORT and GELPOINT.

[0057] 19A, in operation, the serial fluid coupling of the pressure conditioning device 810 to the body conduit by the first fluid coupling 830 and the second fluid coupling 840 of the surgical system results in reduced pulsation and rippling of the body conduit despite the pulsatile action of the insufflation pump 800. The illustrated surgical system also produces a relatively lower pressure at the body conduit compared to an insufflation pump directly coupled to the body conduit. This relatively lower pressure results from the insufflation pump 800 sensing the back pressure of the pressure conditioning device 810 at the first flow coupling 830. Typically, the insufflation pump 800 is configured to provide a pulsed insufflation profile in response to pressure variations at a directly coupled surgical site. However, due to the additional system volume provided by the pressure conditioning device 810 fluidly coupled in series to the internal conduit and the insufflation pump 800, the insufflation pump 800 generates a pulsatile pressure flow in response to pressure variations at the first fluid coupling 830 of the system, which may differ from the pressure at the internal conduit.

[0058] 19B-19F, in various embodiments of a surgical system, it may be desirable to reduce pressure losses at the body conduit that may result from a serially coupled pressure conditioning device 810. With reference to FIG. 19B, the illustrated embodiment of a surgical system includes a pressure conditioning device 810 fluidly coupled to an insufflation pump 800 by a first fluid coupling 830 and to a body conduit by a second fluid coupling 842. The second fluid coupling 842 may have a thick cross-sectional profile defined by a relatively large inner diameter compared to standard insufflation tubing, which typically has an inner diameter of 0.25 inches (6.35 mm). This relatively large inner diameter of the second fluid coupling 842 increases the flow rate of insufflation gas from the pressure conditioning device 810 to the body conduit, thereby maintaining a relatively higher pressure in the body conduit than that of the embodiment of FIG. 19A.

[0059] 19C, the illustrated embodiment of a surgical system includes a pressure conditioning device 810 fluidly coupled to an insufflation pump 800 by a first fluid coupling 830 and to a body conduit by a second fluid coupling 840. The first fluid coupling 830 has a flow splitter, such as a y-junction or y-valve, that provides a dual lumen insufflation gas delivery passageway with a third fluid conduit 834 that provides a parallel fluid flow path from the insufflation pump 800 to the body conduit. This dual lumen insufflation gas delivery passageway increases the flow rate of insufflation gas from the insufflation pump 800 to the body conduit, thereby maintaining a relatively higher pressure in the body conduit than that of the embodiment of FIG.

[0060] 19D, the illustrated embodiment of a surgical system includes a pressure conditioning device 810 fluidly coupled to an insufflation pump 800 by a first fluid coupling 830 and to a body conduit by a second fluid coupling 840. The first fluid coupling 830 can have a one-way valve 836 coupled to a parallel return lumen 838 that is fluidly coupled to the body conduit. This arrangement of one-way valve 836 and return lumen 838 provides backpressure feedback to the insufflation pump 800 while an insufflation gas delivery path is provided from the insufflation pump 800 through the pressure conditioning device 810 to the body conduit, thus maintaining a relatively higher pressure in the body conduit than that of the embodiment of FIG.

[0061] 19E, the illustrated embodiment of the surgical system includes a pressure conditioning device 810 fluidly coupled to the insufflation pump 800 by a first fluid coupling 830 and to the body conduit by a second fluid coupling 840. The surgical system further includes an aspiration device 860 fluidly coupled to the body conduit by a first return conduit 862 and to the pressure conditioning device 810 by a second return conduit 864, thereby defining an insufflation gas return path. Thus, insufflation gas withdrawn from the body conduit is reintroduced into the body conduit via the pressure conditioning device 810. The gas return path may further include an in-line filter to prevent harmful substances from re-entering the body conduit. The aspiration device 860 and return path may compensate for insufflation gas losses, thereby maintaining a desired pressure in the body conduit.

[0062] 19F, the illustrated embodiment of the surgical system includes a pressure conditioning device 810 fluidly coupled to an insufflation pump 800 by a first fluid coupling 830 and to a body conduit by a second fluid coupling 840. The surgical system further includes an aspiration device 860 fluidly coupled to the body conduit by a first return conduit 866 and a reintroduction conduit 868, thereby providing an insufflation gas return path that returns insufflation gas directly to the body conduit. Thus, insufflation gas withdrawn from the body conduit is reintroduced to the body conduit via the reintroduction conduit 868. The gas return path may further include an in-line filter to prevent dangerous materials from being reintroduced into the body conduit. The aspiration device 860 and return path may compensate for insufflation gas losses, thereby maintaining a desired pressure in the body conduit.

[0063] With reference to Figures 20-24, the desired configuration of the pressure conditioning device can be identified by evaluating the pressure conditioning performance in a series of simulated leak tests involving several embodiments of the pressure conditioning device. With reference to Figure 20, baseline results are shown for a simulated leak test test setup including a silicone simulated rectum, a GELPOINT pathway surgical access system, and a standard pulsatile insufflator. A pressure sensor was inserted into the simulated rectum to measure the internal pressure of the system. In a control setup, the GELPOINT pathway stopcock was opened approximately halfway to create a leak rate of 10 L / min. This leak rate was kept constant throughout subsequent testing of the different embodiments of the pressure conditioning device of Figures 21-24. The insufflator was set to a high flow rate at 15 mmHg. The insufflator was turned on after 5 seconds.

[0064] 20 illustrates an exemplary observed pressure (expressed in mmHg) at a simulated surgical site over time (expressed in seconds). As shown, in the baseline or control configuration in which no pressure conditioning device is provided, after an initial delay period of more than 5 seconds, the baseline pressure plot 950 fluctuated between about 6 mmHg and about 25 mmHg, which represents a pressure deviation of 19 mmHg. This fluctuation results in undesirable rippling of the interior walls of the simulated body conduit.

[0065] With reference to Figures 21-24, various embodiments of pressure conditioning devices were incorporated into a simulated surgical site access system for comparison to baseline or control pressure plots. With reference to Figure 21, a pressure plot 960 for a pressure conditioning device having a reservoir of 3L volume is plotted relative to the baseline pressure plot 950. As shown, the addition of the 3L bag reduced the high to low pressure peaks (deviations) to approximately 5mmHg. With reference to Figure 22, a pressure plot 962 for a pressure conditioning device having a reservoir of 5.5L volume is plotted relative to the baseline pressure plot 950. As shown, the addition of the 5.5L reservoir reduced the pressure deviation to approximately 3mmHg. With reference to Figure 23, a pressure plot 964 for a pressure conditioning device having a reservoir of 6.7L volume is plotted relative to the baseline pressure plot 950. The addition of the 6.7L reservoir reduced the pressure deviation to approximately 2.5mmHg. 24, a pressure plot 966 for a pressure conditioning device having a 9 L reservoir is plotted in comparison to a baseline pressure plot 950. The addition of the 9 L reservoir reduced the pressure deviation to approximately 2 mmHg.

[0066] With continued reference to FIGS. 21-24, while increasing the reservoir volume desirably reduced the pressure deviation of the conditioned insufflation gas flow, increasing the reservoir volume also tended to increase the delay time in achieving the desired insufflation pressure at the surgical site. For example, in the embodiments used in the simulated leak test, the observed delay times ranged from about 12 seconds (FIG. 21) to about 30 seconds (FIG. 24). Thus, in certain embodiments, it may be desirable to size the reservoir to provide a relatively small pressure deviation and a relatively small delay time. Additionally, it may be desirable to size the reservoir for ease of positioning and use in the surgical work environment. Thus, in some embodiments, the reservoir may have an internal volume of 5.5-8 liters. More desirably, the reservoir may have an internal volume of at least about 6.5 liters. In certain embodiments, the reservoir may have an internal volume of about 7.4 liters. Desirably, this range of volumes can provide a pressure deviation of less than 3 mmHg, a lag time of less than 30 seconds, and allows the bag to be relatively easy to position in a surgical environment.

[0067] With reference to FIG. 25 and FIG. 26, the pressure conditioning distribution of the surgical site access system including a pressure conditioning device with a 6.5 liter reservoir was further confirmed in a human cadaver. In the experimental surgical access system setup, the stopcock on the surgical access port was opened to create a 7 L / min leak, the insufflator was set to a flow rate of 9 L / min, and the insufflation pressure was set to 15 mmHg. In the control or baseline test, the rectal pressure varied from 2 mmHg to 9 mmHg (a pressure deviation of 7 mmHg). A control pressure plot 970 is shown in FIG. 25, which represents the observed pressure at the mock surgical site plotted over time. The addition of the pressure conditioning device with a 6.5 liter reservoir reduced the pressure deviation to approximately 1 mmHg. FIG. 26 shows a pressure plot 972 for the surgical site access system including the pressure conditioning device.

[0068] 27-30, various embodiments of a pressure conditioning device having a reservoir with a volume of 6.5 liters were evaluated to allow the inner diameter of the outlet tube or fluid coupling to be set to provide a desired pressure conditioning profile. The experimental setup was equipped with a simulated silicone rectum, a GELPOINT pathway surgical access system, a pressure conditioning device having a reservoir as shown, for example, in FIG. 2, and a pulsatile insufflator. The volume of the pressure conditioning device reservoir used was 6.5 L. The outlet tube of the pressure conditioning device was coupled to an insufflation trocar positioned through the surgical access system. A pressure sensor was inserted into the simulated rectum to measure the internal pressure of the system. In a control setup, the GELPOINT pathway stopcock was opened approximately halfway to create a leak rate of 10 L / min to simulate insufflation gas loss and absorption from an open internal conduit. The leak rate was kept constant for all of the pressure conditioning device embodiments. The insufflator was set to a high flow rate of 15 mmHg. The insufflator was turned on after 5 seconds. Outlet tubes of various sizes with inner diameters ranging from 0.1 inch (2.54 mm) to 0.5 inch (12.7 mm) were tested. Figures 27-30 show the simulated surgical site pressure conditioning distributions for embodiments of the pressure conditioning device having different outlet tube inner diameters.

[0069] Referring to FIG. 27, a pressure plot 990 for a pressure conditioning device with an outlet tube of 0.1 inch (2.54 mm) inner diameter is shown compared to a baseline pressure plot 980 for a setup without a pressure conditioning device. This embodiment of the pressure conditioning device maintained a pressure of approximately 9 mmHg at the simulated surgical site. Thus, the resulting pressure conditioning profile has a relatively high pressure drop determined by the difference between the insufflator set pressure and the pressure observed at the surgical site. However, the pressure conditioning profile exhibits relatively little pressure deviation.

[0070] With reference to FIG. 28, a pressure plot 992 of a pressure conditioning device having an outlet tube with a 0.15 inch (3.81 mm) inner diameter is shown compared to the baseline pressure plot 980. As shown, the pressure conditioning profile maintains a pressure of approximately 13 mmHg with a pressure deviation of approximately 1 mmHg. With reference to FIG. 29, a pressure plot 994 of a pressure conditioning device having an outlet tube with a 0.25 inch (6.35 mm) inner diameter is shown compared to the baseline pressure plot 980. As shown, the pressure conditioning profile maintains a pressure of approximately 14 mmHg with a pressure deviation of approximately 1.5 mmHg. With reference to FIG. 30, a pressure plot 996 of a pressure conditioning device having an outlet tube with a 0.5 inch (12.7 mm) inner diameter is shown compared to the baseline pressure plot 980. As shown, the pressure conditioning profile maintains a pressure of approximately 14.5 mmHg with a pressure deviation of approximately 2 mmHg.

[0071] 27-30, comparing the pressure conditioning profiles of various embodiments of the pressure conditioning device, it can be seen that smaller outlet tube inner diameters result in higher overall colorectal system pressure drop but smaller pressure differentials, whereas larger tube inner diameters tend to produce pressure conditioning profiles with minimized colorectal system pressure drop and larger pressure differentials.

[0072] It may be desirable for the insufflation pressure maintained by the surgical site access system to have a relatively low pressure drop and a clinically acceptable pressure deviation. Thus, in some embodiments, the outlet tube may have an inner diameter that desirably ranges from about 0.25 inches (6.35 mm) to about 0.5 inches (12.7 mm). In certain embodiments, the outlet tube may have an inner diameter of about 0.5 inches (12.7 mm). Advantageously, a 0.5 inch (12.7 mm) inner diameter tube exhibits a relatively small pressure drop and a clinically acceptable pressure differential. In a cadaveric laboratory, a pressure differential of 2 mmHg was not visually noticeable. Thus, the pressure differential created by a 0.5 inch (12.7 mm) inner diameter tube is acceptable. Insufflation tubes, such as an inlet tube connecting a pressure conditioning device to an insufflation pump, may typically have an inner diameter of about 0.25 inches (6.35 mm). Thus, it is desirable for the outlet tube to have a larger inner diameter than the inlet tube. In an embodiment of the pressure conditioning device having an outlet tube with an inside diameter of 0.5 inch (12.7 mm), the inside diameter of the outlet tube may be at least twice the inside diameter of the inlet tube.

[0073] In certain other embodiments, it is envisioned that the pressure conditioning device may include other mechanical or electromechanical systems to condition the pulsating flow from the insufflation pump to maintain a substantially constant pressure at the surgical site despite leakage, absorption, and pulsing inputs. In some embodiments, the pulsating gas flow from the insufflation pump may be conditioned using a source of compressed air available for use in the surgical workspace. Referring to FIG. 31, in some embodiments, the pressure conditioning device 1000 includes an insufflation gas reservoir 1020 having a thin gas impermeable membrane that divides the reservoir 1020 into an insufflation chamber 1024 and a pressurized chamber 1026. A compressed air source, for example a compressed air tank 1040, may provide air regulated to a desired pressure by a pressure regulator 1042 to a pressure port 1044 of the pressurized chamber 1026. The pressurized chamber 1026 also includes a check valve 1028 to maintain a desired pressure within the insufflation chamber 1024 and the pressurized chamber 1026.

[0074] 31, in operation, the insufflation pump 1010 is fluidly coupled to the insufflation chamber 1024 at the inlet port 1015, and the insufflation chamber 1024 is filled to capacity with insufflation gas at the desired pressure. The compressed air tank 1040 then pressurizes the pressurized chamber 1026 of the reservoir 1022 to a pressure slightly less than desired for the system but necessary to open the check valve 1028. A decrease in back pressure at the outlet port 1030 of the insufflation chamber 1024 due to leakage or absorption of gas from the surgical site in the system will cause the pressure in the insufflation chamber 1024 to decrease when the insufflation pump 1010 is not continuously pressurizing the system. When the insufflator is turned off, pressurized air from the pressurized chamber 1026 of the reservoir 1020 acts on the flexible membrane 1022 to maintain the pressure in the insufflation chamber 1024 and maintain a substantially continuous supply of insufflation gas to the patient.

[0075] Thus, advantageously, the pressurized two-chamber reservoir can prevent large pressure fluctuations at the surgical site despite the mass of the insufflation gas flow and gas leakage and absorption at the surgical site. When the insufflation pump 1010 is again actuated to increase the pressure in the system, insufflation gas is forced into the insufflation chamber 1024 of the reservoir 1020, and the check valve 1028 opens as the pressurized air is released to return the pressurized chamber 1026 to the desired pressure. The cycle of adding pressurized gas to the pressurized chamber 1026 to maintain insufflation gas pressure in the insufflation chamber 1024 and venting pressurized gas through the check valve 1028 as the insufflation chamber 1024 is pressurized by the insufflation pump 1010 is repeated as necessary in response to fluctuations in the insufflation gas flow rate and gas leakage and absorption at the surgical site.

[0076] Referring to FIG. 32, another embodiment of a pressure conditioning device 1100 is shown diagrammatically. The device receives a flow of insufflation gas from an insufflation pump 1110, and the flow of gas is monitored by a flow sensor 1112 as the gas flows through an insufflation pump 1110 and into an insufflation chamber 1124 of a reservoir 1120 through an insufflation port 1115. The gas flow exits the insufflation chamber 1124 at an outlet port 1130 that is fluidly coupled to the surgical site. Pressure conditioning can be delivered to the reservoir 1120 by a sliding piston or plunger 1122 coupled to a linear actuator 1140 in a position feedback fashion. A programmable logic controller 1160 can monitor the position data from 1140, pressure data from a surgical site pressure sensor 1114, and gas flow data from a flow sensor 1112 to control the responsiveness of the system as a function of inputs received from the sensors. Electrical coupling of the system components is shown in FIG. 32 by dashed lines. The programmable logic controller 1160 may be electrically coupled to the sensors 1112, 1114 and the linear actuator 1140 via wired or wireless connections. A power source 1150 is electrically coupled to the programmable logic controller 1160 to provide power thereto, and may further provide power to the linear actuator 1140.

[0077] In use, in conjunction with an insufflation pump 1110 that provides insufflation gas in a discontinuous or pulsed flow distribution, the pressure conditioning device 1100 can provide consistent pressurization of the system despite leaks and / or pulsed gas flow. In operation, the insufflation pump 1110 fills the insufflation chamber 1124 of the reservoir 1120 to capacity with insufflation gas at the desired pressure. The flow sensor 1112 can detect when the insufflation pump is activated to pressurize the system and when it is no longer activated. Leaks and absorption in the system at the surgical site will cause the pressure to drop when the insufflation pump 1110 is not continuously pressurizing the system. If the insufflation pump 1110 is deactivated, the flow sensor 1112 detects the insufflator state and the plunger 1122 is driven forward by the linear actuator 1140 to maintain a pressure slightly below the desired pressure while collecting constant feedback from the pressure sensor 1114 at the surgical site. By maintaining the pressure below the desired pressure, the insufflation pump 1110 is able to detect leaks in the system before the reservoir 1120 is completely emptied while minimizing fluctuations from cycling in the state of the insufflation pump 1110. When the insufflation pump 1110 is turned on again to increase the pressure in the system, the flow sensor 1112 triggers the plunger 1122 to slowly retract, thereby allowing the insufflation chamber 1124 of the reservoir 1120 to refill. The cycle of forward and retraction motion of the linear actuator is repeated as necessary to maintain a substantially constant pressure at the surgical site.

[0078] Referring to Fig. 33, another embodiment of a pressure conditioning device 1200 is shown in schematic form. The pressure conditioning device 1200 may include a reservoir 1220 containing a free-sliding piston 1222 that divides the reservoir 1220 into an insufflation chamber 1224 and a pressurized chamber 1226. In other embodiments, a separate separator, such as a thin membrane, may divide the reservoir into the insufflation and pressurized chambers as described above with reference to Fig. 31. An insufflation pump 1210 provides a flow of gas to an inlet port 1215 of the reservoir 1220 through a flow sensor 1212. The flow sensor 1212 is electrically coupled to a programmable logic controller 1260 by a wired or wireless connection. The pressurized chamber 1226 of the reservoir 1220 receives compressed air from a compressed air source, such as a compressed air tank 1240, through a pressure regulator 1242. A solenoid valve 1228, electrically coupled to a programmable logic controller (PLC) 1260, can maintain a desired pressure in the pressurized chamber 1226 as a function of input received from the flow sensor 1212. The PLC 1260 can be powered by a power source 1250 electrically coupled thereto. In other embodiments, a check valve can be used in place of the solenoid valve 1228, and the pressure conditioning apparatus can operate substantially similarly to that described above with reference to the embodiment of FIG. 31, without the PLC and flow sensor.

[0079] In conjunction with the insufflation pump, the pressure conditioning device 1200 provides for consistent pressurization of the system despite pulsating insufflation gas flow and leakage or absorption at the surgical site. In operation, the insufflation pump 1210 fills the insufflation chamber 1224 of the reservoir 1220 to maximum capacity with insufflation gas at the desired pressure. The compressed air tank 1240 and pressure regulator 1242 then pressurize the pressurized chamber 1226 of the reservoir 1220 to a pressure slightly lower than that required at the surgical site. The flow sensor 1212 can detect when the insufflation pump 1210 is engaged in pressurizing the system and when the insufflation pump 1210 is no longer engaged. Leakage and absorption of insufflation gas from the surgical site will cause a drop in pressure if the insufflation pump 1210 is not continuously pressurizing the device 1200, thereby reducing the back pressure at the outlet port 1230 of the insufflation chamber 1224. When the insufflation pump 1210 is not providing pressure pulses, compressed air supplied from the compressed air tank 1240 to the pressurized chamber 1226 of the reservoir 1220 pushes the piston 1220, causing it to slide toward the insufflation chamber 1224 to maintain a supply of insufflation gas to the surgical site and prevent large pressure fluctuations due to leakage. When the insufflation pump 1210 is turned on again to increase pressure, the flow sensor 1212 triggers the PLC 1260 to open the solenoid valve 1228, allowing the insufflation gas supplied to the insufflation chamber 1224 to advance the piston 1222 toward the pressurized chamber 1226. The PLC may close the solenoid valve 1228 after a predetermined time has elapsed, insufflation flow conditions, or some other factor. The cycle of the piston sliding toward the insufflation chamber 1224 and then toward the pressurized chamber 1226 is repeated as necessary in response to changes in flow from the insufflation pump 1210 and leakage and absorption at the surgical site.

[0080] 34A-34C, an embodiment of a surgical site sealing device is shown sealing an open body conduit. In some TAMIS procedures or other surgical procedures involving insufflation of an open body conduit, the sealing device may be positioned to form a closed inflatable compartment in the open conduit. Thus, leakage of insufflation gas from the open end of the conduit may be minimized. Various embodiments of the sealing device may be utilized to minimize undulation of the body conduit in an insufflation system in conjunction with the pressure conditioning devices described herein. The sealing device may also reduce gas leakage from the open end of the body conduit, thereby reducing undulation of the body conduit when used in an unconditional pulsed insufflation pump.

[0081] Referring to FIG. 34A, a surgical site closure device can include an elastomeric bag 2100 with an open end 2102 and a closed end 2104 opposite the open end 2102. The elastomeric bag 2100 can be sized and shaped to be positioned within a body conduit, such as the rectum, for a TAMIS procedure. The elastomeric bag 2100 can be inflated such that the bag 2100 has an insertion configuration in which the bag 2100 can be advanced unhindered through the body conduit. The elastomeric bag 2100 can then be inflated to an insufflation state in which the elastomeric bag expands the body conduit. The insufflation gas, such as CO2, is retained within the elastomeric bag 2100 located within the body conduit, such as the rectal cavity. Thus, insufflation pressure loss due to leakage and absorption from the body conduit at the surgical site can be minimized. The surgeon can remove a section of the elastomeric bag 2100 to access the wall of the body conduit for the surgical procedure.

[0082] Referring to FIG. 34B, another embodiment of a surgical site sealing device for sealing an open body conduit is shown. As shown, the sealing device can include an inflatable member, such as a balloon 2200 or pouch, fluidly coupled to an inflation fluid supply tube 2202. The inflatable member can have a deflated state dimensioned to allow it to be advanced through the open end of the body conduit. Once positioned at a desired location within the body conduit, the inflatable member can be inflated with a fluid to an inflated state dimensioned to seal against the wall of the body conduit.

[0083] The inflation tube 2202 extends from a proximal end 2204 to a distal end 2206, with the inflation tube having a lumen 2208 extending between the proximal end 2204 and the distal end 2206. The distal end 2206 of the inflation tube 2202 is coupled to the inflatable member. The lumen 2208 is fluidly coupled to the inflatable member to provide fluid to the inflatable member. The inflation tube 2202 may have a length sufficient to maintain the proximal end 2204 proximal to the open end of the body conduit.

[0084] In use, the balloon 2200 can be advanced in a deflated state to a location within the body conduit beyond the desired treatment site, and then inflated to seal against the wall of the body conduit and form a sealed volume within the body conduit that contains the treatment site. A surgical procedure can then be performed at the treatment site. Once the surgical procedure has been performed, the balloon can be deflated and the inflation tube 2202 can be removed from the body conduit by pulling on the inflation tube 2202. Thus, the inflation tube 2202 can additionally function as a tether to facilitate removal of the balloon 2200.

[0085] Referring to FIG. 34C, another embodiment of a surgical site sealing device for sealing an open body conduit is shown. As shown, the sealing device can include a flexible diaphragm 2300. The sealing device can further include a flexible ring 2302 disposed about the diaphragm. The flexible ring 2302 can be configured into a first configuration in which the flexible ring 2302 can be advanced through the body conduit beyond the treatment site, for example, by compressing, bending, twisting, or rolling the flexible ring. Once positioned beyond the treatment site, the bending, twisting, or rolling of the flexible ring 2302 is released and the biasing force of the ring 2302 tends to configure the ring into a second configuration in which the flexible ring 2302 is generally circular and can seal against the wall of the body conduit. In the illustrated embodiment, the flexible ring 2302 can further include a second outer ring 2306 coupled to the overhanging ring 2302 by a plurality of ribs 2304. This double ring structure can promote better adhesion of the ring to body conduits having uneven surfaces.

[0086] With the ring sealed against the wall of the body vessel, a sealed volume in the body vessel is created. A surgical procedure can then be performed within the sealed volume at the treatment site. Following the surgical procedure, the sealing device can be removed.

[0087] Although the present application discloses certain preferred embodiments and examples, those skilled in the art will recognize that the present invention extends to other variations and / or uses of the invention beyond the specifically disclosed embodiments, as well as obvious modifications and equivalents thereof. Moreover, various features of the invention can be used alone or in combination with other features of the invention other than those expressly set forth above. Thus, the scope of the invention disclosed herein should be determined solely by a fair reading of the appended claims and not by the specific disclosed embodiments described above.

Claims

1. 1. A gas flow pressure conditioning apparatus for a pulsed insufflation pump, comprising: a fluid inlet port configured to receive a flow of gas from the pulsed insufflation pump; an outlet fluid conduit configured to provide a flow of insufflation gas to the surgical site; a reservoir fluidly coupled to the inlet fluid port and the outlet fluid conduit; A gas flow pressure conditioning apparatus, wherein the inlet fluid port has a first inner diameter and the outlet fluid conduit has a second inner diameter greater than the first inner diameter.

2. The gas flow pressure conditioning apparatus of claim 1 , further comprising an inlet fluid conduit fluidly coupled to said inlet fluid port.

3. 2. The gas flow pressure conditioning apparatus of claim 1, wherein said reservoir comprises an elastomeric pouch.

4. 4. The gas flow pressure conditioning device of claim 3, wherein said elastomeric pouch has an outlet port fluidly coupled to said outlet fluid conduit.

5. 4. The gas flow pressure conditioning device of claim 3, wherein said elastomeric pouch has a volume of at least about 6.5 liters.

6. 2. The gas flow pressure conditioning device of claim 1, wherein said second inner diameter is at least twice as large as said first inner diameter.

7. 2. The gas flow pressure conditioning apparatus of claim 1, further comprising an outer envelope positioned about said reservoir.

8. 8. The gas flow pressure conditioning device of claim 7, wherein said outer envelope is comprised of an elastomeric film material.

9. 2. The gas flow pressure conditioning apparatus of claim 1, further comprising an outer sleeve positioned about said reservoir.

10. 10. The gas flow pressure conditioning device of claim 9, wherein said outer sleeve is heat welded to said reservoir at a seam.

11. 1. An insufflation system comprising: a surgical site access port, the surgical site access port comprising: a port surface; a first trocar positionable through the port surface, the first trocar having a first instrument channel extending therethrough; a second trocar positionable through the port surface, the second trocar having a second instrument channel and an insufflation port extending therethrough; A gas flow pressure conditioning device for a pulsed insufflation pump, the gas flow pressure conditioning device comprising: an inlet fluid conduit configured to receive a flow of gas from the pulsed insufflation pump; an outlet fluid conduit configured to provide a flow of insufflation gas to the surgical site access port; a reservoir fluidly coupled to the inlet fluid conduit and the outlet fluid conduit; An insufflation system, wherein the inlet fluid conduit has a first inner diameter and the outlet fluid conduit has a second inner diameter greater than the first inner diameter.

12. The insufflation system of claim 11 , wherein the insufflation port of the second trocar is sized to receive the outlet fluid conduit.

13. The insufflation system of claim 11 , wherein the reservoir comprises an elastomeric film pouch.

14. The insufflation system of claim 11 , wherein the reservoir has a volume of at least 6.5 liters.

15. 12. The insufflation system of claim 11, wherein the second inner diameter is at least about 0.25 inches (6.35 mm) or greater.

16. 12. The insufflation system of claim 11, wherein the second inner diameter is approximately 0.5 inches (12.7 mm).

17. 1. A gas flow pressure conditioning apparatus for a pulsed insufflation pump, comprising: an inlet port configured to receive a flow of gas from the pulsed insufflation pump; an accumulator fluidly coupled to the inlet port; a pressure storage vessel fluidly coupled to the inlet port; a flow restrictor fluidly coupled to the inlet port; a pressure conditioning device having the accumulator, the pressure storage vessel and an outlet port disposed downstream of the flow restrictor in fluid communication with the inlet port;

18. The pressure conditioning device of claim 17 , wherein the accumulator, the pressure storage vessel, and the flow restrictor are fluidly coupled to one another in series between the inlet port and the outlet port.

19. 20. The pressure conditioning apparatus of claim 18, wherein the pressure storage vessel is positioned downstream of the inlet port, the flow restrictor is positioned downstream of the pressure storage vessel, and the accumulator is positioned downstream of the flow restrictor.

20. 20. The pressure conditioning system of claim 17, wherein said pressure reservoir comprises a variable volume container biased to a low volume state.

21. 21. The pressure conditioning device of claim 20, wherein the biasing force of the variable volume container is selected to return gas flow pressure within a predetermined time.

22. 20. The pressure conditioning device of claim 17, wherein the accumulator comprises a fixed volume container.

23. 23. The pressure conditioning apparatus of claim 22, wherein said accumulator has a volume selected to accommodate a predetermined percentage of said gas flow from said insufflation pump.

24. 20. The pressure conditioning apparatus of claim 17, further comprising a gas supply tube fluidly coupled to the inlet port and the outlet port and having a first inner diameter, the flow restrictor comprising a restrictor plate with an orifice disposed in the gas supply tube, the orifice having a second inner diameter smaller than the first inner diameter.

25. 20. The pressure conditioning apparatus of claim 17, wherein the pressure storage vessel comprises a gas container having a wall defined by a bellows surface.

26. 20. The pressure conditioning apparatus of claim 17, wherein the pressure storage vessel comprises a gas container having a flexible wall and a biasing member coupled to the flexible wall to apply a compressive action to the flexible wall.

27. 27. The pressure conditioning device of claim 26, further comprising a housing, said pressure storage vessel and said biasing member positioned within said housing, said biasing member abutting said housing and said gas container.

28. 1. An insufflation system for maintaining a substantially constant pressure at a surgical site, the system comprising: a pulsed insufflation pump having a pump outlet; and a pressure conditioning device, the pressure conditioning device comprising: an inlet fluidly connectable to the pump outlet; a pressure storage vessel; A reservoir; A flow restrictor; and an exit port.

29. 1. A surgical site closure device for sealing an open body conduit, the device comprising: an elastomeric bag having an open end and a closed end opposite the open end, the elastomeric bag being sized and shaped to be positioned within a body conduit; A surgical site closure device, wherein the elastomeric bag has an insertion configuration that allows the elastomeric bag to be advanced unobstructed within the body conduit, and the elastomeric bag is inflatable to an insufflation state in which the elastomeric bag expands the body conduit.

30. 1. A surgical site closure device for sealing an open body conduit, the device comprising: an inflatable member having a deflated state sized to be advanced through an open end of the body vessel and inflatable with a fluid to an inflated state sized to seal against a wall of the body vessel; and an inflation tube extending from a proximal end to a distal end and having a lumen extending between the proximal end and the distal end, the distal end of the inflation tube being coupled to the inflatable member, the lumen being fluidly coupled to the inflatable member to provide the fluid to the inflatable member.

31. 1. A surgical site closure device for sealing an open body conduit, the device comprising: A diaphragm; and a flexible ring disposed about the diaphragm, the flexible ring being configurable into a first configuration in which the flexible ring is advanceable through the body conduit and a second configuration in which the flexible ring is capable of sealing against a wall of the body conduit.

32. 1. An insufflation system for maintaining a substantially constant pressure at a surgical site, the system comprising: a reservoir, the reservoir comprising: an insufflation chamber, the insufflation chamber comprising: an inlet port fluidly connectable to an insufflation pump; and having an outlet port; A pressurized chamber, the pressurized chamber comprising: a pressurized port connectable to a source of pressurized fluid; and A pressure relief valve is provided. A system comprising a separation member fluidly isolating the insufflation chamber from the pressurization chamber, the separation member movable in response to an insufflation pressure in the insufflation chamber and a pressurization pressure in the pressurization chamber.

33. 33. The system of claim 32, wherein the separating member comprises an impermeable membrane.

34. 33. The system of claim 32, wherein the separating member comprises a free-sliding piston.

35. 33. The system of claim 32, wherein the pressure relief valve comprises a check valve selected to allow gas to escape from the pressurized chamber at a predetermined pressure.

36. The pressure relief valve comprises an electrically operated solenoid valve, and the system further includes a control system, the control system comprising: a flow sensor fluidly coupled to the inlet port; 33. The system of claim 32, further comprising a programmable logic controller electrically coupled to the flow sensor and electrically coupled to the solenoid valve, the programmable logic controller configured to operate the solenoid valve in response to an electrical signal from the flow sensor.

37. 33. The system of claim 32, wherein the source of pressurized fluid comprises a compressed air tank.

38. 33. The system of claim 32, further comprising a pressure regulator fluidly coupled to the pressure port.

39. 1. An insufflation system for maintaining a substantially constant pressure at a surgical site, the system comprising: a reservoir, the reservoir comprising: an insufflation chamber, the insufflation chamber comprising: an inlet port fluidly coupled to the insufflation pump; an outlet port; a piston slidable within the reservoir to define a volume of the insufflation chamber; and a pressure control system, the pressure control system comprising: a flow sensor fluidly coupled to the inlet port; a pressure sensor fluidly coupled to the outlet port; a linear actuator operatively coupled to the piston, the linear actuator having a position feedback sensor; An insufflation system comprising a programmable logic controller electrically coupled to the flow sensor, the pressure sensor, the linear actuator, and the position feedback sensor, the programmable logic controller configured to operate the linear actuator to position the piston at a position within the reservoir that maintains a desired pressure at the outlet port in response to electrical signals from the flow sensor and the pressure sensor.

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