Abstract:
Current phacoemulsification handpieces require rigorous cleaning after each procedure because the aspiration and irrigation pathways for fluids are integral to the handpiece. According to the present invention, a removable horn extension and nosecone may be used with a phacoemulsification handpiece to allow for disposable fluid pathways exterior to the handpiece. This will reduce the cleaning time and effort, reduce cross-contamination, and increase the lifespan of the handpiece. Furthermore, the current invention allows different horn extensions to be used to excite different motions at the tip of the handpiece, depending on the preference of the surgeon.

Description:
PRIORITY 
     The present application claims the benefit of U.S. Provisional Application Ser. No. 61/091,270, filed Aug. 22, 2008, which is herein incorporated by reference in its entirety. 
    
    
     THE FIELD OF THE INVENTION 
     The present invention relates to a handpiece used to perform phacoemulsification on patients with cataracts. More specifically, the present invention relates to a handpiece with a removable horn extension and/or nosecone which function as a manifold for irrigation and aspiration fluid paths. 
     BACKGROUND 
     Phacoemulsification is a technique that has revolutionized modern eye cataract surgery. Using phacoemulsification, surgeons can remove cataracts by making only a small incision into the eye. The small incision renders sutures unnecessary and eliminates the need for general anesthesia. Most patients recover very quickly with little impairment or inconvenience. 
     Phacoemulsification devices work by using a handpiece with a needle at the tip that vibrates at an ultrasonic frequency to break apart and emulsify the cataract. This is typically done by selectively powering a plurality of piezoelectric elements disposed adjacent a horn (also known as a wave guide). Expansion and contraction of the piezoelectric elements causes the horn to vibrate, thus causing a needle at the end of the horn to vibrate. 
     A phacoemulsification handpiece essentially performs three tasks simultaneously. The tip of the needle vibrates at an ultrasonic frequency to break apart and emulsify the cataract. A saline solution is fed into the eye to irrigate and to keep the eye from collapsing, and an aspiration line removes liquid and emulsified pieces of the cataract. This maintains the anterior chamber of the eye and also cools the handpiece. 
     Phacoemulsification handpieces have been known since the 1960s. For example, U.S. Pat. No. 3,589,363 was obtained by Charles Kelman. Since then, many improvements have been made upon the initial device. Common current phacoemulsification handpieces consist of a an outer shell which is used as a handle, a needle which is used to break up the cataract, a horn and piezoelectric elements which are used to drive the needle and are held inside the outer shell and a plurality of fluid paths, one for aspiration and the other for irrigation. Examples of such phacoemulsification handpieces are disclosed in U.S. Pat. Nos. 5,178,605 and 5,453,087. 
     As with virtually any non-disposable medical device, contamination and sterilization issues are present. Because the fluid pathways are integral to the handpiece, the handpiece is contaminated with biological waste with each use. Thus, the entire handpiece must be cleaned carefully after each procedure to avoid any possible cross-contamination among patients. The handpiece must undergo a stringent sterilization after each phacoemulsification procedure, especially due to the increasing occurrence of difficult diseases to kill (e.g. Transmissible Spongiform Encephalopathies) and surgery complications potentially due to contaminants from surgical instruments (e.g. Toxic Anterior Segment Syndrome, TASS). 
     The sterilization procedure, while essential for patients&#39; health, can lead to a reduction in the life of the handpiece because of the heat exposure and the difficulty in sealing the handpiece against the high temperature steam used in sterilizing. Because the handpieces are relatively expensive, reduced handpiece life can increase the cost of treating the cataract. Furthermore, the sterilization procedure takes a great deal of effort and time, and is not completely error-free. For example, TASS could be caused by cataract and lens debris which remains in the handpiece, even if the handpiece was sterilized. This may occur since the sterilization procedure relies primarily on heat and may not adequately flush the handpiece or may not flush the handpiece at all. 
     It would be advantageous to provide a phacoemulsification system which did not require complete sterilization of the handpiece as previously done. Thus, it is desired to provide a phacoemulsification handpiece with removable, disposable or limited use fluid pathways for potentially contaminated fluids. These connections could be disposed of after each procedure, thus reducing cleaning effort and time, reducing the risk of possible cross-contamination. Such a handpiece would benefit from an increased lifespan, since the frequency of sterilization of the handpiece could be reduced and the sterilization procedure is harmful to the handpiece. 
     In additional to the above, one common concern with phacoemulsification handpieces is they have traditionally provided only longitudinal motion at the tip of the needle. In some procedures it would be desirable to have a handpiece that provides lateral motion as well. 
     Current phacoemulsification handpieces utilize different motions to emulsify the cataract. For example, a transverse motion of the needle may be used to emulsify the cataract and overcome some of the disadvantages of the traditional longitudinal motion. However, many surgeons prefer one type of motion over the other. Furthermore, phacoemulsification handpieces are expensive and several surgeons often share the same handpiece to save on costs. Thus it is desired to provide a removable horn that allows for different tips with the same handpiece. This would allow multiple surgeons to share the same handpiece, and each could use their preferred tips. This is much more cost-effective than purchasing entire separate handpieces for each surgeon. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide an improved removable horn extension and nosecone with irrigation and aspiration pathways for a phacoemulsification handpiece. It is a further object of the invention to provide a removable horn extension which allows a user to select the type of motion which is imparted to the needle. 
     According to one aspect of the invention, a horn extension is provided that can be easily attached to and detached from a phacoemulsification handpiece. The horn extension can be designed to excite longitudinal motion or lateral motion at the tip of the needle. The horn extension includes seals to prevent cross-contamination of fluids and reduce damping of the oscillating body. 
     According to another aspect of the invention, a removable nosecone is provided which can be easily attached to standard phacoemulsification handpieces. The removable nosecone includes an aspiration port which is connectable to an aspiration line independent of the remainder of the handpiece. Thus, when a procedure is finished, the nosecone and aspiration line can be removed from the remainder of the handpiece without risk that the biological contaminants in the nosecone/aspiration line will make contact with the remainder of the handpiece. This, in turn, significantly reduces the risk of contamination to other patients and lessens the amount of sterilization necessary on the handpiece. 
     According to another aspect of the invention, the nosecone has at least two fluid connection ports—one for aspiration and one for irrigation—but may be designed to have more fluid ports, such as a cooling port. Disposable fluid tubes are attached to the ports such that the fluid pathways enter and exit the nosecone and so that biologically contaminated fluid does not flow through the body of the phacoemulsification handpiece. 
     These and other aspects of the present invention are realized in a removable horn extension and nosecone for a phacoemulsification handpiece as shown and described in the following figures and related description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Various embodiments of the present invention are shown and described in reference to the numbered drawings wherein: 
         FIG. 1  shows a cross-sectional view of a removable horn extension and nosecone according to the present invention; 
         FIG. 2  shows a cross-sectional view of the removable horn extension of  FIG. 1  having a configuration designed to cause lateral needle motion; 
         FIG. 3  shows a cross-sectional view of a the interior components of a standard phacoemulsification handpiece with the horn extension of  FIG. 1 ; 
         FIG. 4  shows a cross-sectional view of an alternative handpiece of the present invention designed with the aspiration lumen and seal grooves incorporated on the large diameter of the horn; 
         FIG. 5  shows a perspective view of the nosecone and horn extension of the current invention joined in one assembly; 
         FIG. 6  shows a cross-sectional view of the nosecone and horn extension of  FIG. 5 ; 
         FIG. 7  shows a cross-sectional view of a standard phacoemulsification handpiece with the removable horn extension and nosecone according to the present invention attached thereto; 
         FIG. 8  shows a detailed view of the irrigation fluid pathway shown in  FIG. 7  in accordance with the present invention; and 
         FIG. 9  shows a detailed view of the aspiration fluid pathway shows in  FIG. 7 . 
     
    
    
     It will be appreciated that the drawings are illustrative of aspects of the present invention and not limiting of the scope of the invention which is defined by the appended claims. The embodiments shown accomplish various aspects and objects of the invention. It is appreciated that it is not possible to clearly show each element and aspect of the invention in a single figure, and as such, multiple figures are presented to separately illustrate the various details of the invention in greater clarity. Similarly, not every embodiment need accomplish all advantages of the present invention. 
     DETAILED DESCRIPTION 
     The invention and accompanying drawings will now be discussed in reference to the numerals provided therein so as to enable one skilled in the art to practice the present invention. The drawings and descriptions are exemplary of various aspects of the invention and are not intended to narrow the scope of the appended claims. 
     Turning now to  FIG. 1 , a cross-sectional view of a removable phacoemulsification needle adapter  1  is shown. The needle adapter  1  includes a horn extension  10  and nosecone  12 . The horn extension  10  and nosecone  12  are attached to a standard phacoemulsification handpiece, generally indicated at  4 . Where prior art phacoemulsification handpieces attached directly to a phacoemulsification needle, the needle adapter  1  is inserted into the handpiece  4  in place of a needle  25  and the needle  25  is attached to the needle adapter  1 . Primarily, the needle adapter  1  isolates the aspirated fluids from the phacoemulsification handpiece  4  and thus alleviates the sterilization requirements for the handpiece itself, allowing the handpiece to be used for multiple procedures without a complete and rigorous sterilization procedure. The adapter  1  also allows for variation of the vibrational mode of the needle  25  while using the same handpiece  4 . 
     The removable horn extension  10  is typically attached to the horn  15  of the surgical handpiece  4  by threaded engagement or a locking bayonet mechanism, exemplified by threaded projection  17   a  and a threaded socket  17   b . The horn  15  is also known as a wave guide, and is driven by a plurality of piezoelectric elements (not shown) forming a Langevin-style transducer. Ordinarily, the horn  15  would have threads or some other mechanism such as the threaded socket  17   b  for attachment to a standard phacoemulsification needle  25 . This mechanism would be used to attach the horn extension  10 , and the horn extension would typically include a similar attachment mechanism such as a threaded socket  19   b  which receives the threads  19   a  on the needle  25 . 
     Wrench flats may be disposed on one or more of the horn extension  10  and horn  15  for ease in connecting the horn extension to the handpiece  4  and needle  25 . Thus, the horn extension  10  is mounted on the horn  15  where the needle would typically be attached in a prior art configuration, and the needle  25  is attached to the horn extension. Alternatively, the needle may be integrally formed with the horn extension. 
     Seals  16  are positioned around a 90 degree bend (bore  11  through the horn extension) in the fluid path (lumen  20 ) connecting an aspiration port  18  to the center aspiration lumen  20  of the horn extension  10 . These seals  16  prevent cross-contamination or fluid leakage. In use, the emulsified cataract and liquid from the eye are drawn in through the needle tip  25   a , down the needle  25 , through the center lumen  20 , and out the aspiration port  18 . 
     The horn extension  10  is covered by a nosecone  12 . As shown, the nosecone  12  has a plurality of fluid connection ports  14 ,  18 ,  22 . The fluid connection ports include a port for aspiration  18  and may include a port for irrigation  14 . As shown in  FIG. 1 , the nosecone  12  includes three fluid connection ports: an aspiration port  18 , an irrigation port  14 , and a cooling fluid port  22 . Irrigation solution flows through the irrigation port  14  and through an irrigation passage  14   a  during a surgical procedure. The cooling fluid port  22  may have access to one or more lumens (such as the center lumen  24 ) in the horn  15 . The cooling fluid cools the piezoelectric elements and adjacent structures of the handpiece  4  and prolongs the life of the handpiece as well as increasing the comfort in using the handpiece. It will be appreciated that cooling the handpiece stack may be achieved by other means as will be described below. 
     The phacoemulsification handpiece includes a sleeve or outer shell  29  which surrounds the horn  15  and forms the outer surface of the handpiece  4 . The outer shell  29  is held by the user when using the handpiece. The nosecone  12  is typically attached to the handpiece outer shell  29 . The nosecone  12  may be attached to the ultrasonic handpiece by threads, a bayonet style locking mechanism, or other suitable means. The nosecone  12  may also be held in place via the threads  17   a  which hold the horn extension  10  to the horn  15 . 
     Turning now to  FIG. 2 , a cross-sectional view of a horn extension  10  that excites lateral motion of the needle  25  according to the present invention is shown. Surgeons may prefer different types of motion (longitudinal versus lateral motion of the needle) according to the particular surgery being performed or according to the tendencies of the individual surgeon. Additionally, multiple surgeons in a group practice may use the same common handpiece  4  to reduce the operational cost associated with their medical practice. According to the present invention, they may switch the adapter  1  to use a different horn extension  10  in order to achieve the desired motion. The horn extension  10  shown in  FIG. 1  produces longitudinal vibration of the needle  25  because the horn extension is symmetrical about its central axis. The horn extension  10  also produces lateral vibration of the needle tip (flexing of the needle) because the horn extension is not symmetrical about its central axis. The horn extension  10   a  utilizes an asymmetric hole  11  through the horn extension body. 
     The particular horn extension  10  is constructed so that the lateral bore  11  of the aspiration port extends from one side of the horn extension to the center of the horn extension rather than extending completely through the horn extension  10  as shown by the lateral bore  11  in  FIG. 1 . Asymmetry may be used to produce lateral motion of the needle tip  25   a . The present invention thus provides a simple and convenient way of producing either longitudinal vibration or lateral vibration as is desired from a single phacoemulsification handpiece  4 . Surgeons may thus have greater control over the surgical procedure without the cost of having two handpieces  4 . 
       FIG. 3  shows a cross-sectional view of the horn extension  10  according to the current invention attached to the horn  15  of a standard ultrasonic handpiece  4  with the outer shell of the handpiece and the nosecone of the horn extension omitted. Another method for cooling the handpiece stack, rather than a third fluid connection site at the nosecone, is through connections in the rearsection  44  of the handpiece  4 . Cooling fluid may be circulated through the handpiece stack by providing a coolant supply  34  and a coolant return  37 . The piezoelectric elements  38  convert electrical energy into mechanical energy to oscillate the horn  15 , and thus produce heat. The cooling fluid removes heat generated by the mechanical movement of the piezoelectric elements  38  and horn  15 . 
     Turning now to  FIG. 4 , an improved handpiece design of the present invention is shown. The horn  15  includes a front face  15   a  which is larger in diameter and which provides a larger mating area for contacting the horn extension  10 . An aspiration port  18  is provided in fluid communication with a central aspiration lumen  20  of the horn extension  10 . Seal grooves  16   a  are formed on the large diameter of the horn extension  10 . Similar seal grooves  16   a  are formed in the horn  15  in order to seal around a cooling fluid port  22  which passes cooling fluid through horn  15  and handpiece via a cooling lumen  24 . Seals are placed in the seal grooves  16   a  as shown previously. The use of a horn  15  with a larger diameter front face  15   a  mated to the larger end of a horn extension  10  provides for less motion at the large diameter of the horn  15  and horn extension  10 . This reduces motion around the seal grooves  16   a  and results in less heating and acoustic losses. 
       FIG. 5  shows another exploded perspective view of a phacoemulsification needle adapter  1  of the present invention. The nosecone  12  and horn extension  10  are combined into one assembly which eliminates some of the seals between the horn extension and nosecone. The nosecone  12  and horn extension  10  form a unitary adaptor  1  which connects to both an ultrasonic handpiece  4  and a needle  25 . The adaptor  1  can be molded together such as by molding the nosecone  12  around the horn extension  10 , or can be made by attaching the horn extension  10  to the nosecone  12  by bonding, sealing or otherwise attaching various components. It is preferred, though not required, that the bonding or sealing occurs at a step in the horn extension (such as at the larger diameter base  10   a  of the horn extension) where a vibrational node having minimal motion occurs so as to reduce losses. An irrigation port and  14  and aspiration port  18  are formed in the nosecone  12 . The irrigation port  14  would be connected to irrigation passages  14   a  (not shown) to allow irrigation fluid to pass out the tip of the adapter  1 . A threaded extension  17   a  or other suitable attachment means is provided at the base end  10   a  of the assembly for attachment to the horn of a standard phacoemulsification handpiece as has been shown. 
     The adaptor assembly  1  (including the various horn extensions and nosecones shown in  FIGS. 1 through 9 ) provides a convenient method for allowing phacoemulsification handpieces to be used repeatedly without requiring complete sterilization between each use, and for allowing a handpiece to be used with different tips and vibrational modes. The adaptor assembly  1  allows the aspirated biological material to be drawn out of the aspiration port  18  so that the biological material never comes into contact with the handpiece. Similarly, the irrigation port  14  allows irrigation fluid to pass only through the adaptor  1  and not through the handpiece. When the procedure is finished, the adaptor assembly  1  can be removed and sterilized or simply discarded. As such the handpiece and its piezoelectric elements need not be subject to rigorous sterilization procedures since the handpiece is not contacted with the biological material or fluids which are introduced into the patient. The handpiece may simply be decontaminated to clean the exterior of the handpiece. Eliminating or reducing the frequency at which the handpiece is rigorously sterilized is anticipated to lengthen its useful life, as the sterilization procedures are harmful to the handpiece piezoelectric elements. 
     As the adaptor assembly  1  has no piezoelectric elements, it is relatively inexpensive to manufacture (allowing it to be disposable if necessary) and allowing the adapter to be sterilized using conventional processes without significant risk that the sterilizing process will damage the adaptor assembly. This also allows a handpiece to be used for multiple surgeries without complete sterilization therebetween by using a different adapter for each surgery. The adapters may be disposed of or sterilized between uses as is desired. As surgical equipment is often sterilized after the day has ended, prior art handpieces often required that a surgeon had a separate handpiece for each surgery which was to be performed during the day, and all of the handpieces were sterilized after the end of the day. The cost of the handpieces is burdensome and may prevent a surgeon from performing a higher number of surgeries during a day. The present invention allows a surgeon to perform multiple surgeries in a single day with a single handpiece, rather than requiring a separate handpiece by simply requiring the surgeon to have multiple adapter assemblies  1  (with the horn extension and nosecone) which may be sterilized or disposed of after the procedures. The present invention thus allows a greater number of persons to be treated while reducing the cost to treat each person. 
       FIG. 6  shows a cross-sectional view of the adaptor assembly  1  of  FIG. 5  taken along the line  6 - 6 . The shape of the horn extension  10  and the nosecone portion  12  of the adapter  1  are visible, showing how the horn extension and the nosecone are connected together at the base  10   a  of the horn extension  10 . It can be seen how the aspiration port  18  is in fluid communication with a central aspiration lumen  20  to draw fluid and biological material through the lumen. A seal  16  may be provided between the horn extension  10  and the nosecone  12  to ensure a good seal of the aspiration lumen between the horn extension  10  and the nosecone  12 .  FIG. 6  illustrates how the irrigation port  14  may be fluidly connected to the lumen  24  of the handpiece  4  and to one or more irrigation passages  14   a  disposed between the horn extension  10  and the nosecone  12 , eliminating an external connection. 
     A threaded extension  17   a  or other connection such as a bayonet style locking mechanism allow for attaching to the handpiece horn  15  of a phacoemulsification handpiece. The tip  10   b  of the horn extension  10   c  is configured to receive a needle  25  as previously shown. Alternatively, the horn extension may include the needle as a part thereof, and the whole assembly may be sterilized or discarded as is appropriate. By combining the horn extension  10  and nosecone  12  into one adaptor assembly  1  assembly, an inexpensive adapter is provided which is quite easy to use with little risk or leaking or failure. Additionally, sealing occurs at a vibrational node, which is more efficient than sealing at off-nodal locations because there is less damping of the oscillating body. The adaptor assembly  1  shown is easy to use because it requires only hand tightening. 
     Turning now to  FIG. 7 , a cut away side view of a standard phacoemulsification handpiece  4  is shown with an adapter  1  having a removable horn extension  10  and nosecone  12  in accordance with the present invention attached. The horn extension  10  and nosecone  12  are similar to those shown in  FIG. 1 . A luer connection  84  and clean saline (irrigation) inlet  80  are disposed at the end of the handpiece. The irrigation path travels along a central lumen  24  which extends through the center of the handpiece  4 . In the process, the irrigation solution passes through the piezoelectric elements  38  and cools the horn. 
       FIG. 8  shows a detailed view of the path taken by the irrigation solution through the handpiece  4  and adapter  1  of  FIG. 7 . As the irrigation solution comes to end of the central lumen  24 , the irrigation solution flows outwardly, leaving the handpiece  4  and entering an irrigation passage  40  which may be formed as part of nosecone  12  or which may be external thereto. After entering the nosecone  12 , the irrigation solution continues on its flow through the irrigation passage  14   a  along the horn extension  10  and out adjacent the needle  25  where it irrigates the eye during surgery. 
     The removable horn extension  10  and nosecone  12  may be designed to be retrofitted into most phacoemulsification systems in the field. The system requirements for the piezoelectric elements handpiece  4 , such as frequency and impedance, can be designed into the current invention through proper selection of material and horn extension size to thereby match the existing handpiece  4 . As will be appreciated by the description of the invention, one or more of the existing fluid pathways and connections of the handpiece may be used without requiring a separate system of fluid lines. In some cases, it may be advantageous to utilize the irrigation or cooling fluid pathways of the handpiece  4 , and even the aspiration pathway as well. In such a case, the present invention is advantageous as it still separates the needle  25  and adapter  1  from the handpiece  4  and thereby reduces the risk of contamination. Additionally, the adapter  1  allows the surgeon to choose between longitudinal or longitudinal and lateral vibration of the needle  25  without requiring an additional handpiece  4 . According to other aspects of the invention, one or more of the fluid pathways such as the irrigation and aspiration pathways may be isolated from the handpiece  4  such that the handpiece need not undergo such a rigorous sterilization. In addition to the other advantages of the invention, this extends the life and reduces the failure risk of the handpiece  4 . 
     Turning now to  FIG. 9 , a partially cut away side view of the handpiece and adapter of  FIG. 7  is shown. The aspiration fluid pathway is discussed to facilitate an understanding thereof. Aspirated fluids, including a fluid such as saline and biological tissue from the eye are drawn into the tip  25   a  of the needle  25 , through the needle lumen horn extension lumen  20 . Aspirated fluids exit the center of the horn extension  10  through a lateral bore  11  or channel leading to the aspiration port  18  in the nosecone  12 . The fluids then travel through tubing  42  which is exterior to the handpiece  4  of the phacoemulsification device. 
     The tubing  42  may bend at about a ninety degree angle or use a similarly shaped elbow fitting  44  so that the tubing continues adjacent to the exterior of the handpiece  4 . Having the tubing  42  disposed adjacent the handpiece helps to keep the tubing from interfering with the surgeons work while operating on patients. Being disposed on the exterior of the handpiece  4 , the tubing  42  can easily be removed and disposed of after each surgical procedure. The nosecone  12  and horn extension  10  may also be discarded, or they may be easily sterilized for reuse. Thus, the biological material which has been aspirated from the eye avoids contact with the handpiece  4  and the various structures which are in contact with the biological material are easily sterilized or inexpensive and disposable. 
     While handpiece  4  shown does come into contact with the irrigation solution, the irrigation solution is typically sterile saline. Thus, minimal sterilization procedures need be taken with the handpiece  4 . This will reduce cross-contamination and cleaning time as well as extend the life of the handpiece  4 . 
     There is thus disclosed an improved removable horn extension and nosecone for use with a phacoemulsification handpiece. It will be appreciated that numerous changes may be made to the present invention without departing from the scope of the claims.