Patent Abstract:
A system for a pneumatically-powered vitrectomy machine includes an output port, a venting valve, a venting manifold, a pressure transducer, and a controller. The output port provides pressurized gas to a vitrectomy probe. The venting valve is located close to the output port. The venting manifold fluidly connects the venting valve to a venting port. The venting port vents pressurized gas from the venting manifold. The pressure transducer is located near the output port. The pressure transducer is configured to read a pressure of a gas near the output port. The controller is adapted to receive information about the pressure and activate the venting valve. When the information received from the pressure transducer indicates a fault condition, the controller directs the venting valve to open.

Full Description:
FIELD OF INVENTION 
     The present invention relates to a pneumatic module for a surgical machine and more particularly to a monitor and gas release valve located near the output end of a vitrectomy machine. 
     BACKGROUND OF THE INVENTION 
     Several conditions of the eye threaten sight. Epiretinal membrane (ERM), also known as macular pucker and cellophane retinopathy, is a condition characterized by growth of a membrane across the macula, or central retina of the eye. This condition may be thought of as the growth of scar tissue across the macula, thus interfering with central vision. The ERM typically contracts, causing distortion of the central retina, thus producing distortion of vision. Most patients will note that either straight objects appear wavy and crooked and/or central vision is reduced, depending on the severity of the condition. 
     Epiretinal membranes may be associated with other conditions of the eye, however, the large majority are idiopathic, which means that the cause is unknown. Some of the disorders which are occasionally associated with ERM&#39;s include previous retinal detachments and surgery thereof, inflammatory conditions (uveitis), retinal tears, and branch retinal vein occlusion (BRVO) and central retinal vein occlusion (CRVO). 
     Another condition is a macular hole. A macular hole is almost always a spontaneous development that occurs predominantly in aging women. The development of a macular hole progresses through several stages, and with each progressive stage the vision may worsen. It has been postulated that shrinkage of the vitreous humor may produce traction on the fovea (central macula), thereby producing the hole itself. However, the cause of macular holes remains under investigation. 
     The retina, which lines the inside of the posterior wall of the eye, may occasionally become detached for various reasons. Most commonly, retinal detachment occurs as a result of a tear or hole in the retina, which develops as a result of a posterior vitreous separation (PVS). The retinal tear or hole allows fluid to enter the subretinal space, thus detaching the retina. 
     The retina receives oxygen and nutrients from the underlying choroid (vascular layer) of the eye. When a retinal detachment occurs, the detached retina begins to dysfunction, and ultimately, necrosis (death) ensues as a result if the retina is not reattached to the underlying choroid. As such, a retinal detachment is an urgent condition. The detached retina should be recognized and treated promptly. 
     Vitreo-retinal procedures may be appropriate to treat these and other serious conditions of the back of the eye. Vitreo-retinal procedures include a variety of surgical procedures performed to restore, preserve, and enhance vision. Vitreo-retinal procedures treat conditions such as age-related macular degeneration (AMD), diabetic retinopathy and diabetic vitreous hemorrhage, macular hole, retinal detachment, epiretinal membrane, CMV retinitis, and many other ophthalmic conditions. 
     The vitreous is a normally clear, gel-like substance that fills the center of the eye. It makes up approximately ⅔ of the eye&#39;s volume, giving it form and shape before birth. Certain problems affecting the back of the eye may require a vitrectomy, or surgical removal of the vitreous. 
     A vitrectomy may be performed to clear blood and debris from the eye, to remove scar tissue, or to alleviate traction on the retina. Blood, inflammatory cells, debris, and scar tissue obscure light as it passes through the eye to the retina, resulting in blurred vision. The vitreous is also removed if it is pulling or tugging the retina from its normal position. Some of the most common eye conditions that require vitrectomy include complications from diabetic retinopathy such as retinal detachment or bleeding, macular hole, retinal detachment, pre-retinal membrane fibrosis, bleeding inside the eye (vitreous hemorrhage), injury or infection, and certain problems related to previous eye surgery. 
     The retinal surgeon performs a vitrectomy with a microscope and special lenses designed to provide a clear image of the back of the eye. Several tiny incisions just a few millimeters in length are made on the sclera. The retinal surgeon inserts microsurgical instruments through the incisions such as a fiber optic light source to illuminate inside the eye, an infusion line to maintain the eye&#39;s shape during surgery, and instruments to cut and remove the vitreous. 
     In a vitrectomy, the surgeon creates three tiny incisions in the eye for three separate instruments. These incisions are placed in the pars plana of the eye, which is located just behind the iris but in front of the retina. The instruments which pass through these incisions include a light pipe, an infusion port, and the vitrectomy cutting device. The light pipe is the equivalent of a microscopic high-intensity flashlight for use within the eye. The infusion port is required to replace fluid in the eye and maintain proper pressure within the eye. The vitrector, or cutting device, works like a tiny guillotine, with an oscillating microscopic cutter to remove the vitreous gel in a controlled fashion. This prevents significant traction on the retina during the removal of the vitreous humor. 
     The surgical machine used to perform a vitrectomy and other surgeries on the posterior of the eye is very complex. Typically, such an ophthalmic surgical machine includes a main console to which numerous different tools are attached. The main console provides power to and controls the operation of the attached tools. 
     The attached tools typically include probes, scissors, forceps, illuminators, and infusion lines. Each of these tools is typically attached to the main surgical console. A computer in the main surgical console monitors and controls the operation of these tools. These tools also get their power from the main surgical console. Some of these tools are electrically powered while others are pneumatically powered. 
     In order to provide pneumatic power to the various tools, the main surgical console has a pneumatic or air distribution module. This pneumatic module conditions and supplies compressed air or gas to power the tools. Typically, the pneumatic module is connected to a cylinder that contains compressed gas. Most commonly, surgeons use cylinders of nitrogen at 3600 psi. The condition and output of these cylinders affect the operation of the surgical machine. 
     The proper gas pressure must be provided by the pneumatic module to the tools in order to insure their proper operation. Providing too high a gas pressure can lead to operational problems. Too high a pressure can damage equipment or lead to a malfunction during surgery. In either case, the instrument itself may be damaged. 
     It would be desirable to incorporate a gas pressure system in an ophthalmic surgical machine to protect the equipment. 
     SUMMARY OF THE INVENTION 
     In one embodiment consistent with the principles of the present invention, the present invention is a system for a pneumatically-powered vitrectomy machine. The system includes a first output port, a venting valve, a first venting manifold, a first pressure transducer, and a controller. The first output port provides pressurized gas to a vitrectomy probe. The venting valve is located close to the first output port. The first venting manifold fluidly connects the venting valve to a first venting port. The first venting port vents pressurized gas from the first venting manifold. The first pressure transducer is located near the first output port. The first pressure transducer is configured to read a first pressure of a gas near the first output port. The controller is adapted to receive information about the first pressure and activate the venting valve. When the information received from the first pressure transducer indicates a fault condition, the controller directs the venting valve to open. 
     In another embodiment consistent with the principles of the present invention, the present invention is a system for a pneumatically-powered vitrectomy machine. The machine includes first and second output ports, first and second venting manifolds, first and second pressure transducers, an output valve, a venting valve, and a controller. The first and second output ports provide pressurized gas to a vitrectomy probe. The output valve directs pressurized gas to the first output port and the second output port. The venting valve is located close to the first output port and the second output port. The first venting manifold connects the venting valve to a first venting port. The first venting port vents pressurized gas from the first venting manifold. The second venting manifold connects the venting valve to a second venting port. The second venting port vents pressurized gas from the second venting manifold. The first pressure transducer is located near the first output port and is configured to read a first pressure of a gas near the first output port. The second pressure transducer is located near the second output port and is configured to read a second pressure of a gas near the second output port. The controller is adapted to receive information about the first pressure and the second pressure and activate the venting valve. When the information received from the first or second pressure transducer indicates a fault condition, the controller directs the venting valve to open. 
     In another embodiment consistent with the principles of the present invention, the present invention is a method of operating a pneumatically-powered vitrectomy machine. A first pressure of a gas near a first output port to which a vitrectomy probe is attached is monitored. A second pressure of a gas near a second output port to which the vitrectomy probe is attached is monitored. A fault condition based on the first or second pressure is detected. A venting valve is opened after the fault condition has been detected. 
     It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are intended to provide further explanation of the invention as claimed. The following description, as well as the practice of the invention, set forth and suggest additional advantages and purposes of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate several embodiments of the invention and together with the description, serve to explain the principles of the invention. 
         FIG. 1  is a block diagram of a pneumatically-powered ophthalmic surgery machine according to an embodiment of the present invention. 
         FIG. 2  is a schematic of a pressure monitor system for a pneumatically powered vitrectomy machine according to an embodiment of the present invention. 
         FIG. 3  is a schematic of a portion of a pressure monitor system for a pneumatically powered vitrectomy machine according to an embodiment of the present invention. 
         FIG. 4  is a flow chart of one method of operation according to an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     Reference is now made in detail to the exemplary embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used throughout the drawings to refer to the same or like parts. 
       FIG. 1  is a block diagram of a pneumatically powered ophthalmic surgical machine according to an embodiment of the present invention. In  FIG. 1 , the machine includes gas pressure monitor system  110 , proportional controller  120 , proportional controller  130 , and tools  140 ,  150 ,  160 , and  170 . The tools  140 ,  150 ,  160 , and  170  can be, for example, scissors, vitrectomy probes, forceps, and injection or extraction modules. Other tools may also be employed with the machine of  FIG. 1 . 
     As shown in  FIG. 1 , gas pressure monitor system  110  is fluidly coupled via a manifold to proportional controller  120  and proportional controller  130 . A single manifold may connect gas pressure monitor system  110  to proportional controller  120  and proportional controller  130 , or two separate manifolds may connect gas pressure monitor system  110  to proportional controller  120  and proportional controller  130 , respectively. Proportional controller  120  is fluidly coupled to tools  140  and  150  by, for example, a manifold and tubing. Likewise proportional controller  130  is fluidly coupled to tools  160  and  170  by, for example, a manifold and tubing. 
     In operation, the pneumatically powered ophthalmic surgery machine of  FIG. 1  operates to assist a surgeon in performing various ophthalmic surgical procedures, such as a vitrectomy. A compressed gas, such as nitrogen, provides the power for tools  140 , 150 ,  160 , and  170 . The compressed gas passes through gas pressure monitor system  110 , through one or more manifolds to proportional controllers  120  and  130 , and through additional manifolds and/or tubing to tools  140 ,  150 ,  160 , and  170 . 
     Gas pressure monitor system  110  functions to monitor the pressure of compressed gas from a gas source as it enters the machine. Proportional controllers  120  and  130  serve to distribute the compressed gas received from gas pressure monitor system  110 . Proportional controllers  120  and  130  control the pneumatic power delivered to tools  140 ,  150 ,  160 , and  170 . Various valves, manifolds, and tubing are used to direct compressed gas from gas pressure monitor system  110 , through proportional controllers  120  and  130 , and to tools  140 ,  150 , 160 , and  170 . This compressed gas actuates cylinders, for example, in tools  140 ,  150 ,  160 , and  170 . 
       FIG. 2  is a schematic of a pressure monitor system for a pneumatically powered vitrectomy machine according to an embodiment of the present invention. In  FIG. 2 , the pressure monitor system includes venting valve  205 , output valve  210 , pressure transducers  215  and  220 , mufflers  225  and  230 , venting manifolds  235  and  240 , manifolds  245 ,  250 ,  255 , and  260 , and output ports A and B. 
     Venting manifold  235  fluidly connects venting valve  205  to muffler  230 . Manifold  245  is also fluidly connected to venting valve  205 . Venting valve  205  is fluidly connected to output valve  210  by manifold  250 . Venting manifold  240  fluidly connects output valve  210  to muffler  225 . Manifold  255  fluidly connects output valve  210  to output port A. Manifold  260  fluidly connects output valve  210  to output port B. Pressure transducer  215  is fluidly connected to manifold  255 . Likewise, pressure transducer  220  is fluidly connected to manifold  260 . 
     In the embodiment of  FIG. 2 , venting valve  205  is a standard two-way valve. As is commonly known, the valve has a solenoid that operates to move the valve to one of the two positions depicted in  FIG. 2 . As shown, the valve is in a venting position. Pressurized gas can pass from manifold  250 , through venting valve  205 , through venting manifold  235 , and out of muffler  230 . In the other position, venting valve  205  allows pressurized gas to pass from manifold  245 , through venting valve  205 , and into manifold  250  where it can provide power to the vitrectomy probe (not shown). Venting valve  205  is controlled by a controller (not shown). 
     Output valve  210  is a standard four-way valve. As is commonly known, the valve has a solenoid that operates to move the valve to one of the two positions depicted in  FIG. 2 . As shown in  FIG. 2 , the valve is in a position to provide pressurized gas to output port A, and to vent pressurized gas from output port B. In this position, pressurized gas can pass from manifold  250 , through output valve  210 , through manifold  255 , and to output port A where the pressurized gas provides pneumatic power to a vitrectomy probe (not shown). Pressurized gas in manifold  260  can pass through output valve  210 , venting manifold  240 , and muffler  225  where it is exhausted to the atmosphere. In the other position, output valve  210  allows pressurized gas to pass from manifold  250 , through output valve  210 , through manifold  260 , and to output port B where the pressurized gas provides pneumatic power to a vitrectomy probe (not shown). Pressurized gas in manifold  255  can pass through output valve  210 , venting manifold  240 , and muffler  225  where it is exhausted to the atmosphere. Output valve  210  is controlled by a controller (not shown). 
     The vitrectomy probe (not shown) that is attached to output ports A and B acts as a cutting device. The cutter is moved by a cylinder that in turn is moved by pressurized gas. The cylinder oscillates as pressurized gas is alternately directed to output ports A and B. Such a vitrectomy device is designed to provide about 5,000 cuts per minute. 
     Pressure transducers  215  and  220  operate to read an atmospheric pressure of the gas contained in manifolds  255  and  260 , respectfully. In other words, pressure transducer  215  reads the pressure of the compressed gas that is adjacent to it in manifold  255 . Likewise, pressure transducer  220  reads the pressure of the compressed gas that is adjacent to it in manifold  260 . In the embodiment of  FIG. 2 , pressure transducers  215  and  220  are common pressure transducers. Pressure transducers  215  and  220  are capable of reading pressure of a compressed gas and sending an electrical signal containing information about the pressure of the compressed gas to a controller (not shown). 
     Manifolds  235 ,  240 ,  245 ,  250 ,  255 , and  260  are all configured to carry compressed gas. In the embodiment of  FIG. 2 , these manifolds are machined out of a metal, such as aluminum. These manifolds are air tight, contain various fittings and couplings, and are designed to withstand relatively high gas pressures. These manifolds maybe manufactured as individual pieces or they maybe manufactured as a single piece. For example, manifolds  235 ,  240 ,  245 ,  250 ,  255 , and  260  may be machined from a single piece of aluminum. 
     Mufflers  225  and  230  are common mufflers designed to suppress the noise made by escaping gas. These mufflers are typically cylindrical in shape. 
     In operation, pressurized gas is directed alternately to output ports A and B to operate the vitrectomy probe. Venting valve  205  is operated in a position that allows pressurized gas to pass from manifold  245 , through venting valve  205 , and into manifold  250 . Output valve  210  is alternated between its two positions very rapidly to provide pressurized gas to output ports A and B. In one position, pressurized gas can pass from manifold  250 , through output valve  210 , through manifold  255 , and to output port A where the pressurized gas provides pneumatic power to a vitrectomy probe (not shown). Pressurized gas in manifold  260  can pass through output valve  210 , venting manifold  240 , and muffler  225  where it is exhausted to the atmosphere. In the other position, output valve  210  allows pressurized gas to pass from manifold  250 , through output valve  210 , through manifold  260 , and to output port B where the pressurized gas provides pneumatic power to a vitrectomy probe (not shown). Pressurized gas in manifold  255  can pass through output valve  210 , venting manifold  240 , and muffler  225  where it is exhausted to the atmosphere. Output valve  210  is controlled by a controller (not shown). 
     In this manner, pressurized gas is provided to output port A while pressurized gas in manifold  260  is allowed to vent through a venting port to which muffler  225  is attached. Likewise, pressurized gas is provided to output port B while pressurized gas in manifold  255  is allowed to vent through a venting port to which muffler  225  is attached. Due to the quick response of the output valve selected, pressurized gas can be alternated very quickly between manifolds  255  and  260 . This allows the vitrectomy probe (not shown) to operate at very high cut rates of about 5,000 cuts per minute. 
     Pressure transducers  215  and  220  monitor the system for a fault condition. When a fault condition is detected in the vitrectomy probe, the pressurized gas is vented to prevent damage to the equipment. In this case, venting valve  205  is in the position shown in  FIG. 2 . In this case, pressurized gas can pass from manifold  250 , through venting valve  205 , through venting manifold  235 , and out of a venting port to which muffler  230  is attached. In the valve positions shown in  FIG. 2 , pressurized gas in manifold  260  can pass through output valve  210 , venting manifold  240 , and out of a venting port to which muffler  225  is attached. Pressurized gas in manifold  255  can pass through output valve  210 , manifold  250 , venting valve  205 , venting manifold  235 , and out of a venting port to which muffler  230  is attached. If the output valve is in the other position, pressurized gas in manifold  255  can pass through output valve  210 , venting manifold  240 , and out of a venting port to which muffler  225  is attached. Pressurized gas in manifold  260  can pass through output valve  210 , manifold  250 , venting valve  205 , venting manifold  235 , and out of a venting port to which muffler  230  is attached. 
     As noted, pressure transducers  215  and  220  monitor the gas pressure in manifolds  255  and  260 , respectively. Pressure transducers  215  and  220  detect fault conditions that may be present during the operation of the vitrectomy probe. In one fault condition, the gas pressure in one or both manifolds  215  and  220  may exceed a threshold thereby posing a threat to the equipment. In such a case, the vitrectomy probe may be damaged. 
     The placement of venting valve  205  close to the output ports A and B allows gas to be quickly vented, effectively turning off the vitrectomy probe to prevent damage to the probe. In general, the faster the pressurized gas can be exhausted from the system in the event of a fault condition, the more likely it is that damage can be prevented. 
       FIG. 3  is a schematic of a portion of a pressure monitor system for a pneumatically powered vitrectomy machine according to an embodiment of the present invention. In  FIG. 3 , controller  300  and interfaces  305 ,  310 ,  315 , and  320  are depicted along with venting valve  205 , output valve  210 , and pressure transducers  215  and  220 . 
     In the embodiment of  FIG. 3 , controller  300  receives pressure information from pressure transducers  215  and  220  via interfaces  305  and  310 , respectively. In this manner, pressure transducer  215  is electrically coupled to controller  300  via interface  305 , and pressure transducer  220  is electrically coupled to controller  300  via interface  310 . Controller sends control signals to venting valve  205  and output valve  210  via interfaces  315  and  320 , respectively. 
     Controller  300  is typically an intergraded circuit capable of performing logic functions. In this manner, controller  300  is in the form of a standard integrated circuit package with power, input, and output pins. In various embodiments, controller  300  is a valve controller or a targeted device controller. In such a case, controller  300  performs specific control functions targeted to a specific device, such as a valve. In other embodiments, controller  300  is a microprocessor. In such a case, controller  300  is programmable so that it can function to control valves as well as other components of the machine. In other cases, controller  300  is not a programmable microprocessor, but instead is a special purpose controller configured to control different valves that perform different functions. 
     Controller  300  is configured to receive signals from pressure transducer  215  via interface  305  and from pressure transducer  220  via interface  310 . These signals, for example, correspond to readings of gas pressure in manifolds  255  and  260 , respectively. Controller  300  is also configured to send output signals via interfaces  315  and  320  to venting valve  205  and output valve  210 , respectively. These output signals allow controller  300  to control the operation of venting valve  205  and output valve  210 . 
     Interfaces  305  and  310  are designed to carry signals from pressure transducers  215  and  220  to controller  300 . In this case, interfaces  305  and  310  are common electrical conductors such as wires. Likewise, interfaces  315  and  320  carry signals from controller  300  to venting valve  205  and output valve  210 . Interfaces  305 ,  310 ,  315 , and  320  may be one or more wires or buses designed to carry electrical or data signals. 
       FIG. 4  is a flow chart of one method of operation according to an embodiment of the present invention. In  FIG. 4 , one method of operating the pressure monitor system of  FIGS. 2 and 3  is described. In  405 , a fault condition is sensed by sensing a first and/or second gas pressure at a first and/or second output port of a vitrectomy probe. In  410 , a determination is made as to whether a fault condition has been detected. If a fault condition has been detected, then in  415 , a venting valve is opened, and in  420 , and indication of the fault condition is provided. If a fault condition has not been detected in  410 , then the method returns to  405 . 
     The indication of a fault condition, which in some instances is a high gas pressure, can be provided visually or audibly. If visually, a light emitting diode may be illuminated, an indication may appear on a display, or a similar visual event may occur. If audibly, a warning sound may be emitted. Any other type of indication or combination of visual and audible indications may be provided in accordance with the various embodiments of the present invention. 
     From the above, it may be appreciated that the present invention provides an improved system and methods for monitoring the gas pressure in a pneumatic module of a vitrectomy machine. The present invention provides features designed to protect the equipment from harm due to high gas pressure. The present invention is illustrated herein by example, and various modifications may be made by a person of ordinary skill in the art. 
     Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.

Technology Classification (CPC): 5