Abstract:
An infusion sleeve has a flexible tube enclosing a lumen. The tube has a plurality of wall segments, each wall segment located between the lumen and an exterior surface of the tube and extending parallel to a central axis of the tube. The plurality of wall segments includes at least two thick wall segments and at least two thin wall segments alternately arranged such that each thick wall segment is adjacent to two thin wall segments, and each thin wall segment is adjacent to two thick wall segments.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The present invention relates to phacoemulsification surgery and more particularly to an infusion sleeve that reduces the likelihood of injury to delicate eye structures during surgery. 
         [0002]    The human eye functions to provide vision by transmitting light through a clear outer portion called the cornea, and focusing the image by way of a crystalline lens onto a retina. The quality of the focused image depends on many factors including the size and shape of the eye, and the transparency of the cornea and the lens. When age or disease causes the lens to become less transparent, vision deteriorates because of the diminished light which can be transmitted to the retina. This deficiency in the lens of the eye is medically known as a cataract. An accepted treatment for this condition is surgical removal of the lens and replacement of the lens function by an artificial intraocular lens (IOL). 
         [0003]    In the United States, the majority of cataractous lenses are removed by a surgical technique called phacoemulsification. A typical surgical hand piece suitable for phacoemulsification procedures consists of an ultrasonically driven phacoemulsification hand piece, an attached hollow cutting needle surrounded by an irrigation sleeve, and an electronic control console. The hand piece assembly is attached to the control console by an electric cable and flexible tubing. Through the electric cable, the console varies the power level transmitted by the hand piece to the attached cutting needle. The flexible tubing supplies irrigation fluid to the surgical site and draws aspiration fluid from the eye through the hand piece assembly. 
         [0004]    The operative part in a typical hand piece is a centrally located, hollow resonating bar or horn directly attached to a set of piezoelectric crystals. The crystals supply the required ultrasonic vibration needed to drive both the horn and the attached cutting needle during phacoemulsification, and are controlled by the console. The crystal/horn assembly is suspended within the hollow body or shell of the hand piece by flexible mountings. The hand piece body terminates in a reduced diameter portion or nosecone at the body&#39;s distal end. Typically, the nosecone is externally threaded to accept the hollow irrigation sleeve, which surrounds most of the length of the cutting needle. Likewise, the horn bore is internally threaded at its distal end to receive the external threads of the cutting tip. The irrigation sleeve also has an internally threaded bore that is screwed onto the external threads of the nosecone. The cutting needle is adjusted so that its tip projects only a predetermined amount past the open end of the irrigation sleeve. 
         [0005]    During the phacoemulsification procedure, the tip of the cutting needle and the end of the irrigation sleeve are inserted into the anterior capsule of the eye through a small incision in the outer tissue of the eye. The surgeon brings the tip of the cutting needle into contact with the lens of the eye, so that the vibrating tip fragments the lens. The resulting fragments are aspirated out of the eye through the interior bore of the cutting needle, along with irrigation solution provided to the eye during the procedure, and into a waste reservoir. 
         [0006]    Throughout the procedure, irrigating fluid is introduced into the eye, passing between the irrigation sleeve and the cutting needle and exiting into the eye at the tip of the irrigation sleeve and/or from one or more ports, or openings, in the irrigation sleeve near its end. The irrigating fluid protects the eye tissues from the heat generated by the vibrating of the ultrasonic cutting needle. Furthermore, the irrigating fluid suspends the fragments of the emulsified lens for aspiration from the eye. 
         [0007]    Power is applied to the hand piece to vibrate the cutting needle. In general, the amplitude of needle movement (or vibration) is proportional to the power applied. In conventional phacoemulsification systems, the needle vibrates back and forth producing a longitudinal needle stroke. In improved systems, the needle may be caused to vibrate in a twisting or torsional motion. Regardless of the type of vibration, the magnitude of vibration (or amplitude of needle stroke) varies with applied power. 
         [0008]    One complication that may arise during the procedure is damage to eye structures such as the iris. As the needle vibrates torsionally, it imparts circumferential motion to the irrigation sleeve. The circumferential vibrations transmitted by the sleeve to an eye structure, such as the iris, may damage it. An improved irrigation sleeve may be used to decrease the physical force transmitted by circumferential motion of the sleeve to eye structures. 
       SUMMARY OF THE INVENTION 
       [0009]    In one embodiment consistent with the principles of the present invention, the present invention is an infusion sleeve has a flexible tube enclosing a lumen. The tube has a plurality of wall segments, each wall segment located between the lumen and an exterior surface of the tube and extending parallel to a central axis of the tube. The plurality of wall segments includes at least two thick wall segments and at least two thin wall segments alternately arranged such that each thick wall segment is adjacent to two thin wall segments, and each thin wall segment is adjacent to two thick wall segments. 
         [0010]    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 
         [0011]    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. 
           [0012]      FIG. 1  is a diagram of the components in the fluid path of a phacoemulsification system. 
           [0013]      FIGS. 2A-2C  are perspective views of the distal end of a phacoemulsification needle and irrigation sleeve according to the principles of the present invention. 
           [0014]      FIGS. 3A-3C  are cross section views of a prior art infusion sleeve. 
           [0015]      FIGS. 4A-4C  are cross section views of an infusion sleeve according to the principles of the present invention. 
           [0016]      FIGS. 5A-5C  are cross section views of an infusion sleeve according to the principles of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0017]    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. 
         [0018]    In one embodiment of the present invention,  FIG. 1  is a diagram of the components in the fluid path of a phacoemulsification system.  FIG. 1  depicts the fluid path through the eye  1145  during cataract surgery. The components include an irrigation fluid source  1105 , an irrigation pressure sensor  1130 , an irrigation valve  1135 , an irrigation line  1140 , a hand piece  1150 , an aspiration line  1155 , an aspiration pressure sensor  1160 , a vent valve  1165 , a pump  1170 , a reservoir  1175  and a drain bag  1180 . The irrigation line  1140  provides irrigation fluid to the eye  1145  during cataract surgery. The aspiration line  1155  removes fluid and emulsified lens particles from the eye during cataract surgery. 
         [0019]    When irrigation fluid exits irrigation fluid source  1105 , it travels through irrigation line  1140  and into the eye  1145 . An irrigation pressure sensor  1130  measures the pressure of the irrigation fluid in irrigation line  1140 . An optional irrigation valve  1135  is also provided for on/off control of irrigation. Irrigation pressure sensor  1130  is implemented by any of a number of commercially available fluid pressure sensors and can be located anywhere in the irrigation fluid path (anywhere between the irrigation source  1105  and the eye  1145 ). 
         [0020]    A hand piece  1150  is placed in the eye  1145  during a phacoemulsification procedure. The hand piece  1150  has a hollow needle (as seen in  FIG. 2 ) that is ultrasonically vibrated in the eye to break up the diseased lens. A sleeve located around the needle provides irrigation fluid from irrigation line  1140 . The irrigation fluid passes through the space between the outside of the needle and the inside of the sleeve (as more clearly shown in  FIG. 2A ). Fluid and lens particles are aspirated through the hollow needle. In this manner, the interior passage of the hollow needle is fluidly coupled to aspiration line  1155 . Pump  1170  draws the aspirated fluid from the eye  1145 . An aspiration pressure sensor  1160  measures the pressure in the aspiration line. An optional vent valve can be used to vent the vacuum created by pump  1170 . The aspirated fluid passes through reservoir  1175  and into drain bag  1180 . 
         [0021]      FIG. 2A  is a perspective view of the distal end of a phacoemulsification hand piece according to the principles of the present invention. In  FIG. 2 , a phacoemulsification needle  1210  is surrounded by an irrigation sleeve  1230 . The phacoemulsification needle  1210  has an open end  1220  through which lens particles are aspirated from the eye during cataract surgery. The irrigation sleeve  1230  has an optional opening  1240  through which irrigation fluid flows into the eye. The needle  1210  and sleeve  1230  are both inserted into the anterior chamber of the eye during cataract surgery. When power is applied to the hand piece, the needle  1210  vibrates ultrasonically. This is more clearly seen in  FIGS. 2B and 2C . In  FIG. 2B , needle  1210  vibrates in longitudinal mode (back and forth). In  FIG. 2C , needle  1210  vibrates in torsional mode (or in a twisting or sweeping manner). 
         [0022]    The two different modes (longitudinal and torsional) produce two different needle motions as shown in  FIGS. 2B and 2C . In general, longitudinal mode can act to cut a cataractous lens by impacting the end of the needle  1210  against the lens much like a jackhammer. Torsional mode can act to cut a lens with a side to side sweep of the end of the needle  1210 . Depending on the needle geometry, the twisting motion imparted to the needle  1210  in torsional mode generally produces a side to side sweep of the end of the needle  1210 . In other instances, the end of the needle  1210  sweeps in an arc. Regardless, torsional mode may be more effective in cutting a lens because it allows aspiration through open end  1220  of needle  1210  to hold the lens material on the needle  1210  for more effective cutting. In addition, in torsional mode, each sweep of the needle  1210  acts to cut the lens. In contrast, longitudinal mode produces a jack hammer motion that impacts the lens only in a forward direction (and not in a return direction). Moreover, longitudinal mode may act to repel the lens material away from the needle which may reduce cutting efficiency. 
         [0023]    The effect of the sweeping motion of needle  1210  on the irrigation sleeve is shown in  FIGS. 3A-3C .  FIGS. 3A-3C  are cross section views of a prior art infusion sleeve. A needle would occupy the lumen  310  of sleeve  300 . As shown in  FIG. 3A , sleeve  300  has a generally circular cross section as does the lumen  310  bounded by sleeve  300 . In this manner, sleeve  300  is generally cylindrical or tube shaped with an interior passage or lumen  310  that has a circular cross section. In  FIGS. 3A-3C , the boxes on the sleeve wall located at twelve, three, six, and nine o&#39;clock are for illustrating the sleeve movement seen in  FIGS. 3B and 3C . 
         [0024]    As shown in  FIGS. 3B and 3C , when a needle (not shown) located in lumen  310  is vibrated torsionally or in a sweeping manner (needle motion denoted by “M”), a circumferential, radial or rotating motion is imparted to sleeve  300  (sleeve motion is denoted by “R”). Needle motion M alternately compresses each side of the wall of sleeve  300  while expanding the other side of the wall of sleeve  300 . The top and bottom walls of sleeve  300  generally move circumferentially in an arc R. In this manner, torsional vibration of the needle (not shown) in lumen  310  causes significant motion of the sleeve  300 . Force is transmitted from the needle to the sleeve  300  in the direction of needle motion M resulting in a compression of a side wall of sleeve  300  as shown. In addition, the walls of sleeve  300  (top and bottom walls shown in  FIGS. 3B and 3C ) move circumferentially around the needle. Such motion may damage eye structures such as the iris. 
         [0025]      FIGS. 4A-4C  are cross section views of an infusion sleeve according to the principles of the present invention. In  FIG. 4A , sleeve  400  has an internal lumen  410 , two thick walls  420 , and two thin walls  430 . Lumen  410  has an oblong cross section, although other cross sections, such as an elliptical cross section, may also be employed. The needle would be located in lumen  410 . The exterior of the sleeve  400  has a generally circular cross section and is in the shape of a tube. In this example, two thick walls  420  are located at twelve and six o&#39;clock, and two thin walls  430  are located at three and nine o&#39;clock. In  FIGS. 4A-4C , the boxes on the sleeve wall located at twelve, three, six, and nine o&#39;clock are for illustrating the sleeve movement seen in  FIGS. 4B and 4C . 
         [0026]    While the location of thick walls  420  and thin walls  430  are shown at twelve and six o&#39;clock and at three and nine o&#39;clock, respectively, in other embodiments of the present invention, thick walls  420  and thin walls  430  may be located at any point on the sleeve as long as they are alternated. In other words, as one travels around the periphery of sleeve  400 , one would encounter a thick wall  420  followed by a thin wall  430 , followed by a thick wall  420 , etc. Any number of thick walls  420  and thin walls  430  may be employed. 
         [0027]    As shown in  FIGS. 4B and 4C , when a needle (not shown) located in lumen  410  is vibrated torsionally or in a sweeping manner (needle motion denoted by “M”), a much smaller circumferential or rotating motion is imparted to the thick walls  420  of sleeve  400  (thick wall  420  motion is denoted by “R”). Needle motion M alternately deforms each thin wall  430 . The thick walls  420  of sleeve  400  generally move very slightly circumferentially in an arc R. In general, the thin walls  430  are deformable such that little circumferential motion is imparted to the thick walls  420 . Moreover, deformation of thin walls  430  also imparts very little force to adjacent eye structures. As such, the improved sleeve design of  FIG. 4A  reduces the force applied to eye structures by the sleeve  400  when in use. 
         [0028]      FIGS. 5A-5C  are cross section views of an infusion sleeve according to the principles of the present invention. In  FIG. 5A , sleeve  500  has an internal lumen  510 , two thick walls  520 , and two thin walls  530 . Lumen  510  has an oblong cross section, although other cross sections, such as an elliptical cross section, may also be employed. The needle would be located in lumen  510 . The exterior of the sleeve  500  has a generally circular cross section and is in the shape of a tube. In this example, two thick walls  520  are located at three and nine o&#39;clock, and two thin walls  530  are located at twelve and six o&#39;clock. In  FIGS. 5A-5C , the boxes on the sleeve wall located at twelve, three, six, and nine o&#39;clock are for illustrating the sleeve movement seen in  FIGS. 5B and 5C . 
         [0029]    While the location of thick walls  520  and thin walls  530  are shown at three and nine o&#39;clock and at twelve and six o&#39;clock, respectively, in other embodiments of the present invention, thick walls  520  and thin walls  530  may be located at any point on the sleeve as long as they are alternated. In other words, as one travels around the periphery of sleeve  500 , one would encounter a thick wall  520  followed by a thin wall  530 , followed by a thick wall  520 , etc. Any number of thick walls  520  and thin walls  530  may be employed. 
         [0030]    As shown in  FIGS. 5B and 5C , when a needle (not shown) located in lumen  510  is vibrated torsionally or in a sweeping manner (needle motion denoted by “M”), small linear motion is imparted to the thick walls  520  of sleeve  500  (thick wall  520  motion is denoted by “D”). Needle motion M alternately deforms each thin wall  530 , much as the thin walls  430  of  FIGS. 4B and 4C  are deformed. The thick walls  520  of sleeve  500  generally move very slightly to and fro in a linear manner D. In general, the thin walls  530  are deformable such that little motion is imparted to the thick walls  520 . Moreover, deformation of thin walls  530  also imparts very little force to adjacent eye structures. As such, the improved sleeve design of  FIG. 5A  reduces the force applied to eye structures by the sleeve  500  when in use. 
         [0031]    The sleeves  400 ,  500  depicted in  FIGS. 4A-4C  and  5 A- 5 C are made of an elastic material such as silicone or other suitable polymer. As such, the sleeves  400 ,  500  are flexible and can deform as shown in  FIGS. 4B ,  4 C,  5 B, and  5 C. The sleeves  400 ,  500  may also be described as generally flexible tubes. In addition, the cross section views shown in  FIGS. 4A-4C  and  5 A- 5 C may represent the sleeve at any point or at particular points along the needle that is inserted into the eye. The sleeves  400 ,  500  may have the same or a different cross section at a location that is not inserted into the eye (for example, at a location further posterior the end of the needle). For example, the distal one third of the sleeve may have a cross section shown in  FIGS. 4A-4C  and  5 A- 5 C, while the proximal two thirds may have a different cross section (such as the cross section of a simple flexible tube without thick and thin segments). In another example, the sleeve has the same cross section along the entire length of the needle. Other combinations of cross sections along the length of the sleeve may also be employed. 
         [0032]    From the above, it may be appreciated that the present invention provides an improved irrigation sleeve for phacoemulsification surgery. The present invention provides an irrigation sleeve with thick wall and thin wall segments that decrease the amount of motion transferred to adjacent eye structures when a needle located in the lumen of the sleeve is vibrated torsionally. The present invention is illustrated herein by example, and various modifications may be made by a person of ordinary skill in the art. 
         [0033]    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.