SYSTEM AND METHOD FOR EFFECTING WATER HAMMER IN SURGICAL SYSTEMS

The present invention discloses a system comprising an actuation valve for receiving a first pressurized fluid, a piston in communication with the actuation valve, and a flow restrictor for controlling the flow of a second pressurized fluid from the piston. The flow restrictor may vent to ambient pressure and the piston may act as a pinch valve on at least one of an irrigation line.

BACKGROUND

Field of Technology

The present disclosure relates generally to phacoemulsification surgical systems. In particular, the present disclosure relates to reducing the effects of water hammer in certain fluidic systems within phacoemulsification systems including those system employing pinch valves.

Description of the Background

Cataracts affect more than 22 million Americans age 40 and older, and as the U.S. population ages, more than 53 million Americans are expected to have cataracts by the year 2030. Cataract surgery entails the removal of a lens of an eye that has developed clouding of the eye's natural lens, or opacification. As a result of opacification, light is unable to travel to the retina, thereby causing vision loss. Once vision becomes seriously impaired, cataract surgery is a viable option with a high level of success. During cataract surgery, a surgeon replaces the clouded lens with an intraocular lens (IOL).

Certain surgical procedures, such as phacoemulsification surgery, have been successfully employed in the treatment of certain ocular problems, such as cataracts. Phacoemulsification surgery utilizes a small corneal incision to insert the tip of at least one phacoemulsification handheld surgical implement, or handpiece, through the corneal incision. The handpiece includes a needle which is ultrasonically driven once placed within the incision to emulsify the eye lens, or to break the cataract into small pieces. The broken cataract pieces or emulsified eye lens may subsequently be removed using the same handpiece, or another handpiece, in a controlled manner. The surgeon may then insert a lens implant into the eye through the incision. The incision is allowed to heal, and the result for the patient is typically significantly improved eyesight.

During the phacoemulsification process for cataract removal, a consumable plastic cassette is generally used to collect effluent material. The disposable plastic cassette may consist of a tubing cassette which has flow paths for fluid and one or more valves to stop fluid flow or adjust fluid flow. In such phacoemulsification fluidics, there is a need for fluid to be valved off to stop fluid flow. To complicate matters, in a medical application such as phacoemulsification surgery, there cannot be a traditional direct in line valve.

Currently, companies use solenoid pinch valves, pneumatic pinch valves and rotary valves to shut off fluid flow in surgical system having small diameter tubing. Specifically, for solenoid and pneumatic pinch valves applications, the speed at which the irrigation valve opens can cause a water hammer effect on the fluid in the line and may cause a significant drop of pressure in the surgical field, namely the eye chamber, and may cause patient discomfort. Thus, there needs to be an apparatus and method to indirectly close off the fluid path through a consumable cassette while limiting any disruption to the pressure in the fluid line.

SUMMARY

Various embodiments recite a system for reducing water hammer effects in a phacoemulsification surgical system. The system may comprise an actuation valve for receiving a first pressurized fluid, a piston in communication with the actuation valve, and a flow restrictor for controlling the flow of a second pressurized fluid from the piston portion, which may include, for example, a piston, housing associated with the piston, and any associated sealing means. The flow restrictor may have a diameter of about 0.016 inches. The first pressurized fluid may be about 25 to about 50 psi apply a force to a return spring associated with the piston. The flow restrictor may vent to ambient pressure and the piston may act as a pinch valve on the irrigation line.

Various embodiments may also include a method for reducing water hammer effects in a phacoemulsification surgical system. The method may comprise actuating a linear actuator pinch valve to a first position with a first pressurized fluid and releasing a portion of the first pressurized fluid through a flow restrictor wherein the linear pinch valve moves to a second position. The flow restrictor may have a diameter of about 0.016 inches. The first pressurized fluid may about 25-50 psi and may comprise a balanced salt solution (BSS) fluid.

DETAILED DESCRIPTION

Embodiments are provided throughout so that this disclosure is sufficiently thorough and fully conveys the scope of the disclosed embodiments to those who are skilled in the art. Numerous specific details are set forth, such as examples of specific components, devices, and methods, to provide a thorough understanding of embodiments of the present disclosure. Nevertheless, it will be apparent to those skilled in the art that certain specific disclosed details need not be employed, and that exemplary embodiments may be embodied in different forms. As such, the exemplary embodiments should not be construed to limit the scope of the disclosure. As referenced above, in some exemplary embodiments, well-known processes, well-known device structures, and well-known technologies may not be described in detail.

Referring now toFIG. 1A, an eye treatment system10for treating an eye E of a patient P generally includes an eye treatment probe handpiece110coupled with a console115by a cassette170. Handpiece110generally includes a handle for manually manipulating and supporting an insertable probe tip. The probe tip has a distal end which is insertable into the eye, with one or more lumens in the probe tip allowing irrigation fluid to flow from console115and/or cassette170into the eye. Aspiration fluid may also be withdrawn through a lumen of the probe tip, with console115and cassette170generally including a vacuum aspiration source, a positive displacement aspiration pump, or both to help withdraw and control a flow of surgical fluids into and out of eye E. As the surgical fluids may include biological materials that should not be transferred between patients, cassette170will often comprise a sterilizable (or alternatively, disposable) structure, with the surgical fluids being transmitted through flexible conduits120of cassette170that avoid direct contact in between those fluids and the components of console115.

When a distal end of the probe tip of handpiece110is inserted into an eye E, for example, for removal of a lens of a patient P with cataracts, an electrical conductor and/or pneumatic line (not shown) may supply energy from console115to an ultrasound transmitter of handpiece110, a cutter mechanism, or the like. Alternatively, handpiece110may be configured as an irrigation/aspiration (I/A) and/or vitrectomy handpiece. Also, the ultrasonic transmitter may be replaced by other means for emulsifying a lens, such as a high energy laser beam. The ultrasound energy from handpiece110helps to fragment the tissue of the lens, which can then be drawn into a port of the tip by aspiration flow. So as to balance the volume of material removed by the aspiration flow, an irrigation flow through handpiece110(or a separate probe structure) may also be provided, with both the aspiration and irrigation flows being controlled by console115.

To avoid cross-contamination between patients without incurring excessive expenditures for each procedure, cassette170and its flexible conduits120may be disposable. However, the flexible conduit or tubing may be disposable, with the cassette body and/or other structures of the cassette being sterilizable. Cassette170may be configured to interface with reusable components of console115, including, but not limited to, peristaltic pump rollers, a Venturi or other vacuum source, a controller125, and/or the like.

Console115may include controller125, which may include an embedded microcontroller and/or many of the components common to a personal computer, such as a processor, data bus, a memory, input and/or output devices (including a user interface130(e.g. touch screen, graphical user interface (GUI), etc.), and the like. Controller125will often include both hardware and software, with the software typically comprising machine readable code or programming instructions for implementing one, some, or all of the methods described herein. The code may be embodied by a tangible media such as a memory, a magnetic recording media, an optical recording media, or the like. Controller125may have (or be coupled with) a recording media reader, or the code may be transmitted to controller125by a network connection such as an internet, an intranet, an ethernet, a wireless network, or the like. Along with programming code, controller125may include stored data for implementing the methods described herein and may generate and/or store data that records parameters corresponding to the treatment of one or more patients.

Referring now toFIG. 1B, a simplified surgical system145comprising console115is illustrated, where a fluid path may be demonstrated under an exemplary embodiment. In this example, an irrigation source151may be configured as a bottle or bag hanging from an IV pole hanger150. It is understood by those skilled in the art that, while an integrated IV pole is illustrated, other configurations, utilizing standalone/static IV poles, pressurized infusion sources, and/or other suitable configurations, are contemplated by the present disclosure.

An exemplary irrigation path for fluid may be realized via tubing cassette170coupled with cassette tubing interface153, which receives fluid from irrigation source151via drip chamber152. Irrigation line156A and aspiration line157are coupled to handpiece158. Irrigation fluid may flow from drip chamber152through the irrigation tubing156into tubing cassette170. Irrigation fluid may then flow from the tubing cassette through handpiece irrigation line156A which may be coupled to an irrigation port on handpiece158. Aspirated fluid may flow from the eye through the handpiece aspiration line157back to tubing cassette170and into a waste collection bag155. Cassette170may be removably engaged with console115in cassette receptacle161which may be shaped to accept only a cassette compatible with console115. A touch screen display130may be provided to display system operation conditions and parameters, and may include a user interface (e.g., touch screen, keyboard, track ball, mouse, etc.—see touchscreen/user interface130ofFIG. 1A) for entering data and/or instructions to the system ofFIG. 1B.

FIG. 2is a schematic illustrating a portion of the pinch valve system in an exemplary embodiment. Pinch valve system200may comprise at least one pinch valve and is housed in console115and controlled by the console and/or through the user interface130. A pinch valve associated with the pinch valve system200may be positioned to act on at least one portion of tubing associated with a cassette170attached to the console115.

Pinch valve system200may be pneumatic and may include at least one piston portion205associated with an irrigation line. The piston portion may comprise at least one pneumatic piston, which may, preferably, comprise a pinch valve. The piston portion may also be fluidly associated with an activation assembly which may control the flow of compressed fluid to a piston portion. For example, activation assembly220may be fluidly connected to piston portion205by line211.

The irrigation activation assembly220may comprise an irrigation activation valve203and at least one vent201. Irrigation activation valve203may receive a compressed fluid from pneumatic fluid source210and controls the delivery of the compressed fluid to piston portion205. Control of irrigation activation valve203may be through console115and may be responsive to the user of the console and/or to automated console controls. Vent201may provide venting to atmosphere and may be fluidly connected to irrigation activation valve203and may provide both pressure regulation for received fluid pressure and venting which may be used to regulate both received fluid pressure(s) and to release pressure exerted on piston portion205.

In an embodiment of the present invention, fluid delivered from pneumatic fluid source210, preferably in the form of air, has a pressure greater than atmosphere and may, preferably, have a pressure of about 25-50 psi. Pneumatic fluid source210may have a reservoir and/or pump associated therewith. The pressurized fluid is communicated to activation valve203which, upon activation, communicates a portion of the received fluid to piston portion205. The received pressurized fluid may act on piston233. A return spring234is associated with piston233and may provide resistance and/or tension to the lateral movement of piston233. The pressure of the pneumatic fluid used in pinch valve system200may vary and may be calibrated to the spring's constant value k. Such calibrating of pressure may allow for a high degree of control over the speed of actuation of piston portion205.

For example, the piston233of piston portion205may be fully actuated instantaneously in response to an applied fluid pressure to act on, for example, a portion of tubing to stop fluid flow in the tubing, and may be slowly released by bleeding off the supplied fluid pressure through, for example, vent201. This type of control over the releasing of the piston and the allowing of continued fluid flow in the tubing provides a reduction in water hammer effects down flow from the piston, or more specifically, between the pinch valve created by the piston acting on the tubing and the terminus point for fluid flowing in the tubing (i.e., the surgical site).

Control over the speed of actuation of the pneumatically actuated piston233of the present invention may be controlled by the delivery of pressurized fluid and the release or bleeding of fluid pressure on piston portion205. Using compressed air as the fluid, the present invention may provide any value of pressure from pneumatic fluid source210to either activation valve203, such as, for example, air pressurized to at least 30 psi. Each activation valve may also release the pressure on the piston through a flow restrictor (207) associated with the vent (201,208). For example, flow restrictor207may be in communication with activation valve203and vent201and may have a diameter of less the 0.02 inches and may, preferably, have a diameter of 0.016 inches to reduce the speed and turbulence of releasing the pressure on piston portion205.

As illustrated inFIGS. 3A and 3B, console115may comprise piston portion205, with at least a portion of piston portion205, e.g. a portion of piston233, extending beyond a surface of console115or beyond a surface of or into a portion of a cassette receptacle161of the console115. The pinch valve portion310may form a part of piston233and may be positioned to interact with tubing outside of the console115, such as, for example, in a surgical cassette removably associated cassette receptacle161of console115. For example, as illustrated inFIG. 3C, pinch valve portion310associated with piston portion205may come in contact with and partially reduce flow in tubing315. When piston233is fully actuated, pinch valve portion310may, as illustrated inFIG. 3D, fully inhibit fluid flow in tubing315as pinch valve portion310may substantially and/or fully stop flow of fluids in tubing315.

The tip of pinch valve portion310may be of any shape which may allow the pinch valve portion310to compress tubing315to affect the flow of fluid in tubing315without damaging the tubing. The tubing may be resident in a surgical cassette and may provide a rigid surface on which tubing315may reside and against which pinch valve portion310may actuate against. As would be appreciated by those skilled in the art, the stiffness of the tubing and tip of the pinch valve portion310may be varied in relation to the viscosity and pressure of the fluid being transported in tubing315.

As illustrated inFIG. 4, the use of a pneumatically driven linear actuator as described above greatly reduces the variance in fluid pressure changes that may result from a surge in fluid pressure if fluid flow is released in too abrupt a manner. More specifically, as demonstrated by the irrigation fluid pressure measured at the point of use, the opening of the pressurized irrigation line using a solenoid valve, for example, as illustrated by line405, may result in a variety of pressure variations versus the target pressure B. The quick release of the pressurized fluid first results in a larger than desired pressure A which proceeds a follow-on water hammer effect measured between time 1600 and about 1900, until the pressure returns to nearly about the target pressure of B. Using a pneumatic linear actuator, as illustrated by line410, the pressure registered immediately following opening the irrigation line may be controlled to the pressure of C. This greater control over pressure and volume greatly diminishes any water hammer between time 1600 and about 1900 and allows the first measured pressure C to be nearly that of the operational target pressure B.

Those of skill in the art will appreciate that the herein described apparatuses, devices, systems and methods are susceptible to various modifications and alternative constructions. There is no intention to limit the scope of the invention to the specific constructions described herein. Rather, the herein described systems and methods are intended to cover all modifications, alternative constructions, and equivalents falling within the scope and spirit of the disclosure, any appended claims and any equivalents thereto.

In the foregoing detailed description, it may be that various features are grouped together in individual embodiments for the purpose of brevity in the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that any subsequently claimed embodiments require more features than are expressly recited.

Further, the descriptions of the disclosure are provided to enable any person skilled in the art to make or use the disclosed embodiments. Various modifications to the disclosure will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other variations without departing from the spirit or scope of the disclosure. Thus, the disclosure is not intended to be limited to the examples and designs described herein, but rather are to be accorded the widest scope consistent with the principles and novel features disclosed herein.