Abstract:
A phacoemulsification system is disclosed. The system includes a phacoemulsification handpiece and selectively detachable infusion sleeve. The infusion sleeve may include a single body portion defined by a first open end and a second open end and having a hollow interior portion therein. The body portion may include multiple layers with at least one inner layer and at least one outer layer, such that the layers are constructed of separate and distinct materials.

Description:
PRIORITY CLAIM 
       [0001]    This application claims the benefit of priority of U.S. Provisional Patent Application Ser. No. 61/423,183 titled “Infusion Sleeve With Multiple Material Layers”, filed on Dec. 15, 2010, whose inventors are Grace Chuang Liao and Karen T. Hong, which is hereby incorporated by reference in its entirety as though fully and completely set forth herein. 
     
    
     TECHNICAL FIELD 
       [0002]    The present disclosure generally relates to the field of phacoemulsification, and more specifically the field of infusion sleeves. 
       BACKGROUND 
       [0003]    Typical phacoemulsification ultrasonic surgical devices consist of an ultrasonically driven handpiece with an attached cutting tip and irrigating sleeve, also known as an infusion sleeve, with an electronic control module. The handpiece generally includes an irrigation line, aspiration line and a power cord, all of which are generally interconnected to, and controlled by, the control module. In use, the cutting tip and attached infusion sleeve are inserted into a small incision in a cornea, or other location. The control module varies a power level in the handpiece to ultrasonically vibrate the cutting tip, while providing irrigation between the infusion sleeve and cutting tip. The control module also provides a vacuum through a port in the cutting tip. 
         [0004]    The infusion sleeve is the only part, other than the cutting tip, that comes into contact with a patient. Thus, the infusion sleeve&#39;s operability is extremely important for the overall performance of the phacoemulsification equipment. One concern in phacoemulsification surgical procedures is the problem of heat build-up in the cutting tip. Wound pressure on the infusion sleeve walls compresses the walls and causes both reduced fluid flow to and from the cutting tip and heat-producing frictional contact between the vibrating cutting tip and the walls of the infusion sleeve. Thus, as cooling fluid flow is diminished, frictional heat increases without a means to dissipate the heat. The heat build-up can cause scleral or corneal burns very quickly. This problem becomes an increasing concern when higher frequency (i.e. higher energy) vibrations are used. Passively, corneal burns may be mitigated by a surgeon through appropriate adjustments of a combination of operating parameters, such as the amount of phaco power delivered and the volume of irrigation/aspiration flow. Additionally, some prior art handpiece assemblies (or probes) generally have relied solely on a textured inner sleeve wall and the flow of the irrigant between the cutting tip and the sleeve and the flow of aspirated material into the cutting tip bore to cool the cutting tip. However, a viscoelastic material injected into the anterior ocular chamber during a typical phacoemulsification procedure resists the flow of the irrigant out of the sleeve and is highly resistant to aspiration flow into the cutting tip bore. Therefore, the flow of aspiration and irrigation fluids into and out of the eye can be momentarily occluded whenever the cutting tip and sleeve come into contact with the viscoelastic material. This momentary occlusion can result in sudden cutting tip overheating and resultant scleral and/or corneal lesions. Thus, because cutting tip overheating occurs very rapidly (within 1 to 3 seconds), even short term exposure to such overheating can cause injury to delicate eye tissue. 
         [0005]    Other prior art attempts to prevent heat transmission methods have been employed through the use of “Mackool tips.” A Mackool tip is a two part infusion sleeve having an inner rigid sleeve that is inserted into and surrounded by an outer malleable sleeve. The inner rigid sleeve is considered as part of the Mackool phaco tip and sits loosely on a main shaft portion of the Mackool phaco tip. The purpose of the inner rigid sleeve is to decouple the vibrating needle from the infusion sleeve. The inclusion of the inner rigid sleeve results in a much more dramatic reduction of heat. 
         [0006]    While the Mackool tip has been proven effective in reducing heat generation, there remains room for improvement. Specifically, the need arises for an infusion sleeve that eliminates the use of the separate inner rigid sleeve, while still providing additional heat reducing properties with reduced friction in a single piece infusion sleeve. 
       BRIEF SUMMARY 
       [0007]    A phacoemulsification system is disclosed. The system includes a phacoemulsification handpiece and selectively detachable infusion sleeve. The infusion sleeve may include a single body portion defined by a first open end and a second open end and having a hollow interior portion therein. The body portion may include multiple layers with at least one inner layer and at least one outer layer, such that the layers are constructed of separate and distinct materials. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    Exemplary embodiments of the present disclosure will now be described by way of example in greater detail with reference to the attached figures, in which: 
           [0009]      FIG. 1  is a perspective view of an exemplary phacoemulsification handpiece assembly; 
           [0010]      FIG. 2  is an enlarged perspective view of an exemplary multi-layer infusion sleeve engaged with the phacoemulsification handpiece of  FIG. 1 ; 
           [0011]      FIG. 3  is a perspective cut-away view of the exemplary multi-layer infusion sleeve of  FIG. 2 , illustrating internal areas of the infusion sleeve; and 
           [0012]      FIG. 4  is an enlarged perspective cut-away view of the exemplary multi-layer infusion sleeve of  FIG. 3 , illustrating the multiple layers of the infusion sleeve. 
           [0013]      FIG. 5  is an enlarged cut-away view of a portion of the exemplary multi-layer infusion sleeve with raised protrusions for friction relieving elements. 
           [0014]      FIG. 6  is an enlarged cut-away view of a portion of the exemplary multi-layer infusion sleeve with recessed valleys for friction relieving elements. 
           [0015]      FIG. 7  is an enlarged cut-away view of a portion of the exemplary multi-layer infusion sleeve with a low friction coating for the friction relieving element. 
       
    
    
     DETAILED DESCRIPTION 
       [0016]    Referring now to the discussion that follows and also to the drawings, illustrative approaches to the disclosed devices and methods are shown in detail. Although the drawings represent some possible approaches, the drawings are not necessarily to scale and certain features may be exaggerated, removed, or partially sectioned to better illustrate and explain the present disclosure. Further the descriptions set forth herein are not intended to be exhaustive or otherwise limit or restrict the claims to the precise forms and configurations shown in the drawings and disclosed in the following detailed description. 
         [0017]    Referring to  FIGS. 1 and 2 , an exemplary phacoemulsification device  10  is illustrated. The phacoemulsification device  10  is defined by a distal end  12  and a proximal end  14 , with a hollow handpiece body portion  16  spanning therebetween. The body portion  16  may be rotatively interconnected at the distal end  12  with an irrigation infusion sleeve  50  (best seen in  FIG. 2 ). The body portion  16  may generally include an ultrasonically driven internal cannula  20  that extends internally from the proximal end  14  to an integrated cutting tip  22  at the distal end  12 . The internal cannula  20  may be in communication with a power cord  30 , which controls power for ultrasonic vibrations of the cutting tip  22  and an aspiration line  32  for removal of emulsified cataract tissue or aspirant. Additionally, an irrigation line  34  may be fluidly connected to a tube  56 , having a hollow area  60 , (best seen in  FIGS. 3 and 4 ) between an inner surface  62  of the infusion sleeve  50  and an outer surface of the cannula  20 . 
         [0018]    As can be seen in  FIGS. 1 and 2 , the infusion sleeve  50  may be attached directly fixed to the distal end  12  of the body portion  16  of the phacoemulsification device  10 . The infusion sleeve  50  may generally include a main body or base section  52  that extends from a connection at the distal end  12  of the body portion  16  to a conical nose section  54  that tapers down from the base section  52  to an elongated tube section  56 . The infusion sleeve  50  generally includes the hollow area  60  that extends interiorly from the base section  52  to a tapered tip  58 . The tapered tip  58  may include one or more fluid ports  70  that fluidly connect the inner hollow area  60  with an incision in the corneal area. Additionally, the infusion sleeve  50  may also include protrusions  66  (best seen in  FIG. 2 ) extending from an outer surface  64  of the infusion sleeve  50  at the conical nose section  54  or the base section  52 . The protrusions  66  may provide rigidity and added grip for handling the phacoemulsification device  10 . 
         [0019]    Turning to  FIGS. 3 and 4 , an exemplary fusion sleeve  50  is illustrated in cross-section. The infusion sleeve  50 , as illustrated, includes threads  68  for rotatively connecting the infusion sleeve  50  to the body portion  16 . However, other connecting elements may be used, such as, but not limited to, tongue and groove arrangements, latching male and female tabs, twist lock male tabs and corresponding female receptacles (i.e., luer-type arrangements) and other known elements that provide a sealing connection between the infusion sleeve  50  and the body portion  16 . With further reference to  FIG. 3 , the inner hollow area  60  may be seen as it transitions from the threaded portion  68  and tapers down to the tapered tip  58 , where the fluid ports  70  are positioned. Specifically, as discussed above, the fluid ports  70  may be positioned about an outer periphery of the tapered tip  58 . The fluid ports  70  may be of any size and of any shape depending on the application. As illustrated, the fluid ports  70  are circular apertures that are positioned on opposing sides. 
         [0020]    As illustrated in  FIGS. 3 and 4  and discussed above, the infusion sleeve  50  includes the outer surface layer  64  and the inner surface layer  62 . In the exemplary arrangement, the outer surface layer  64  extends the length of the infusion sleeve  50  and may be made with materials that provide a minimization of heat and motion transfer. Generally, such outer surface layer  64  materials may include, but are not limited to, a silicone, a polyimide, a polyethylene and an acetal. Each material may have a specific equivalent durometer range (discussed below) with a general thermal conductivity in the range of 0.1-0.9 W/(m*° K). Specifically, silicone may have a durometer ranging from 30-80 Shore A, polyimide may have a durometer ranging from 65-92 Shore D, polyethylene may have a durometer ranging from 45-53 Shore D and acetal may have a durometer ranging from 70-88 Shore D. However, regardless of which material is used the durometer of the outer layer material will be lower than the durometer of the inner layer material, as the inner layer is more rigid than the outer layer. Specifically, the outer surface layer  64  may be used to minimize the heat and motion transfer that may be transmitted to the cornea, which may help reduce the likelihood of corneal burns and mechanical trauma during a phacoemulsification surgery procedure. The softer material used may also provide better sealing about the incision, thereby reducing any incisional leakage that may occur. 
         [0021]    Additionally, the inner surface layer  62  may be made with materials providing a relatively stiff surface that may have a relatively low coefficient of friction such that the surface friction is minimized against the vibrating cutting tip  22 . Generally, such inner surface layer  62  materials may include, but are not limited to an injection-moldable polyimide, and an acetal. These materials may typically have a coefficient of friction value approximately in a range of 0.1 to 0.3. The inner surface layer  62  may also include mechanical features, such as, but not limited to, bumps  80  (see  FIG. 5 ), ribs, ridges, recessed valleys  82  (see  FIG. 6 ), or other such friction relieving elements causing a random disruption in the inner surface layer  62 . The mechanical features may be used in conjunction with specific manufacturing materials that are different than that of the outer surface  64 . Additionally, the inner surface layer  62  may include (either separately or in combination with one or more other friction relieving elements) a low-friction coating  84  (see  FIG. 7 ) as a friction relieving element. The coating may be, but is not limited to a parylene N or other types of parylene coatings and a FluoroBond® LSR (Orion Industries) or other known fluoropolymer coatings generally having a coefficient of friction approximately in the range of 0.1 to 0.3. Depending on the application, the layer materials, mechanical features and coatings may be used simultaneously or each may be used individually. In some embodiments, at least two different layers are used and the inner layer material is more rigid than the outer layer material. 
         [0022]    Multiple layers may be used to simultaneously impart additional heat and friction-reducing properties, as opposed to the previous single material designs and previous multi-piece designs. In one exemplary arrangement, the two layers  62 ,  64  may be created using multi-layer injection molding or overmolding processes. Merely by way of example, multi-component, multi-shot and over-molding process may be employed to create a multiple layered infusion sleeve in a unitary construction. 
         [0023]    Multi-component molding may be further subdivided into co-injection, bi-injection and interval injection. Co-injection molding involves making sequential injections into the same mold with one material as the core and one as the skin. It may also be known as sandwich molding because the core is fully encapsulated. Bi-injection molding is the simultaneous injection of different materials through different gates. Interval injection molding, also known as marbling, is the simultaneous injection of different materials through different gates giving limited mixing. 
         [0024]    Multi-shot molding describes any process where distinct material shots are applied to produce the final component. This includes transfer molding, injection molding, core back molding and rotating tool molding. Where multiple slugs of different materials may be injected into the mold to create the multiple layered product. 
         [0025]    Over-molding includes both insert molding and lost core molding, the latter produces hollow parts. Over-molding allows the desired part to be preformed and then reinserted into a mold for an additional layer of material to be applied to the original part. 
         [0026]    In use, the infusion sleeve threads  68  may be rotatively engaged with corresponding threads in the body portion  16  to lock the two pieces as one unit. Further assembly includes attaching the aspiration line  32 , irrigation line  34  and power cord  30  to the control module to create a phacoemulsification assembly. It should be known that the infusion sleeve  50  may be of various diameters and lengths to accommodate specific phacoemulsification cannula  20  and body portions  16 . Infusion sleeve  50  selection may include selecting a sleeve to allow the cutting tip  22  to extend a predetermined distance from the end of the infusion sleeve  50  to allow for proper alignment of the cutting tip  22  extending past the fluid ports  70 . This may allow the cutting tip  22  to provide enough ultrasonic vibration to breakup or emulsify the cataract and draw in just the cataract tissue and not draw additional liquid from the incision. This predetermined distance may also help to eliminate any irrigant from being drawn directly from the hollow area  60  within the infusion sleeve  50 . 
         [0027]    Once the assembly is created, an operator may activate the control module to cause the phacoemulsification device cannula  20  to vibrate ultrasonically, and these vibrations are transmitted along to the cutting tip  22  where the vibrations are used to fracture or emulsify a cataract or other phaco-type tissue. A vacuum source may be activated to draw the emulsified tissue or aspirant through a central lumen  24  in the cannula  20  (illustrated in  FIGS. 1 and 2 ) starting at the cutting tip  22  and extending through the body portion  16  to a flexible aspiration line  32  that extends to the control module. An irrigant source supplies an irrigant such as saline solution under pressure through irrigation line  34  and that extends along the body portion  16  to the hollow area  60  in the infusion sleeve  50  where the irrigant is forced to migrate along the inner surface layer  62  in the tube  56  between the tube  56  and the cannula  20 . The tube  56  may be dimensioned to fit securely around the cannula  20 , which allows the irrigant to exit the infusion sleeve  50  through the fluid ports  70  to provide lubrication to the incision area. 
         [0028]    As discussed above, the interaction between the infusion sleeve  50  and the cannula  20  may result in overheating and unwanted vibration. Therefore the exemplary infusion sleeve  50  may be constructed with an additional layer  72  of material, as illustrated in  FIG. 4 . The additional layer  72  may provide additional friction-relieving properties, additional heat resistance properties, or a combination thereof, as discussed above regarding the materials used in producing the multi-layered infusion sleeve  50 . These additional requirements may depend upon the predetermined and desired applications. It should be known that when the mechanical elements are used, the amount of frictional contact area between the cannula  20  and the inner surface  62  may be reduced/minimized to lower the frictional heat created by the vibrations. In addition, when mechanical elements are used, an additional lubricity may be retained due to material selection or by retaining the irrigant within the recesses of the elements to continuously supply a small amount of irrigant even if the main flow of irrigant is interrupted, thereby continuously bathing the cannula  20  and ultimately the cutting tip  22  with the lubricating irrigant. 
         [0029]    It will be appreciated that the devices and methods described herein have broad applications. The foregoing embodiments were chosen and described in order to illustrate principles of the methods and apparatuses as well as some practical applications. The preceding description enables others skilled in the art to utilize methods and apparatuses in various embodiments and with various modifications as are suited to the particular use contemplated. In accordance with the provisions of the patent statutes, the principles and modes of operation of this disclosure have been explained and illustrated in exemplary embodiments. 
         [0030]    It is intended that the scope of the present methods and apparatuses be defined by the following claims. However, it must be understood that the exemplary embodiments may be practiced otherwise than is specifically explained and illustrated without departing from its spirit or scope. It should be understood by those skilled in the art that various alternatives to the embodiments described herein may be employed in practicing the claims without departing from the spirit and scope as defined in the following claims. The scope of the disclosure should be determined, not with reference to the above description, but should instead be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. It is anticipated and intended that future developments will occur in the arts discussed herein, and that the disclosed systems and methods will be incorporated into such future examples. Furthermore, all terms used in the claims are intended to be given their broadest reasonable constructions and their ordinary meanings as understood by those skilled in the art unless an explicit indication to the contrary is made herein. In particular, use of the singular articles such as “a,” “the,” “said,” etc. should be read to recite one or more of the indicated elements unless a claim recites an explicit limitation to the contrary. It is intended that the following claims define the scope of the disclosure and that the method and apparatus within the scope of these claims and their equivalents be covered thereby. In sum, it should be understood that the exemplary embodiment is capable of modification and variation and is limited only by the following claims.