Abstract:
A device for performing an anterior capsulotomy procedure and a method using the same is presented. The device includes a body having a rotatable cutting element rotatably disposed on the proximal end. The cutting element further includes multiple surgical blades. In certain embodiments, the device further includes an arcuate member, wherein two surgical blades are attached at opposing ends and extend outwardly from the arcuate member. In using the device to perform an anterior capsulotomy, the device is inserted into an incision made in an eye and the surgical blades are brought in contact with the anterior capsule wall. The anterior capsule wall is then transformed by rotating the rotatable cutting element, creating an aperture there through.

Description:
BACKGROUND 
     The present invention relates generally to medical devices and more particularly to medical devices for performing an anterior capsulotomy (capsulorrhexis). 
     During cataract surgery, or removal and replacement of the natural lens of the eye, a surgeon must enter the globe, using a small millimeter blade, to access the cataract, which commonly involves the centermost layer (the cortex) of the lens. Most often, a clear corneal suture-less incision of 3 mm or less is made. The anterior chamber is then filled with a viscoelastic substance to protect the cornea during cataract surgery and to maintain the integrity of the anterior chamber when necessary. An additional incision called a paracentesis is placed at approximately 90° (ninety degrees) to facilitate the manipulation of the cataract during phaco emulsification, a process that utilizes ultrasound to gently suction out the cataract. 
     Prior to the suctioning of the cataract, an opening in the capsule is needed to allow for the use of devices required to effectively remove cortex and mucleus from the capsule. It is of the utmost importance that the integrity of the anterior (after anterior capsulotomy) and posterior capsule is maintained. Post-operatively the capsular envelope serves as a retainer for an artificial implant (intra-ocular lens (IOL). Without the capsule, or if the structure is compromised, the use of a posterior implant may be contraindicted since the capsule provides the support needed to keep the artificial lens in place. 
     There are two prior art methods of performing an anterior capsulotomy. The first, referred to as the “can opener” technique, is an older procedure before more modern techniques and advanced equipment (such as the Utrata forceps) became available. This procedure involves the surgeon making a series of small, connected punctures using a cystotome, or bent needle, running 360° (three-hundred and sixty degrees) around the anterior portion of the capsule, resulting in an opening that resembles the appearance of the top of an open can. 
     The second method requires the surgeon to nick the anterior portion of the capsule with a cystotome to create a tear in the membrane. Using an Utrata forceps, an edge of the tear is grasped and guided to create a circular aperture in the surface of the anterior capsule. 
     Both techniques require significant skill on the part of the surgeon and generally take years to master. Even a slight error, can result in a devastating prognosis for the patient. If the capsulotomy is too small, the cataract may not be removed sufficiently, If the capsulotomy is too large or the anterior capsule tears during the process, extending and resulting in a posterior capsular tear, the capsule may not be able to support the artificial lens implant or, worse yet, there may be a loss of the vitreous. If a vitreous loss occurs an immediate vitrectomy is required, which has the potential of a lifetime of visual impairment or blindness for the patient. Furthermore, the use of many newer intraocular lenses require that the anterior capsulotomy be performed such that a circular opening with a predetermined diameter be made. 
     Thus, the prior art methods for performing anterior capsulotomies possess inherent deficiencies that increase the likelihood of complications and decrease the procedure&#39;s safety. Therefore, there is a need for a means of reliably and safely performing an anterior capsulotomy. 
     SUMMARY 
     In one implementation, a device for performing an anterior capsulotomy procedure is presented, wherein the device is disposable after a single use. The device includes a body having a rotatable cutting element rotatably disposed on the proximal end. 
     In another implementation, the rotatable cutting element of the device further includes an arcuate member having opposing first and second ends. A first surgical blade is attached to the first end and the second surgical blade is attached to the second end, the surgical blades extending outwardly from the arcuate member. 
     Another implementation, a method of performing an anterior capsulotomy is presented. The method includes making an incision in an eye. A device is then provided and inserted into the incision. The device has a rotatable cutting element disposed on the proximal end of the device, the cutting element having multiple blades and being operatively coupled to an actuator. The actuator can be moved from a first to a second position, causing the rotatable cutting element to rotate. The method further includes bringing the surgical blades in contact with the anterior capsule wall and transforming it by moving the actuator from the first to the second position, thereby creating an aperture therein. 
     And yet another embodiment, the rotatable element of the provided device further includes an arcuate member having opposing first and second ends. A first surgical blade is attached to the first end and the second surgical blade is attached to the second end, the surgical blades extending outwardly from the arcuate member. The method of performing the anterior capsulotomy further includes rotating the arcuate member about 180 degrees. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Implementations of the invention will become more apparent from the detailed description set forth below when taken in conjunction with the drawings, in which like elements bear like reference numerals. 
         FIG. 1  is a prospective view of a human eyeball illustrating the prior art practice of performing an anterior capsulotomy; 
         FIG. 2  is an exemplary stylet or needle used to perform an anterior capsulotomy according to the prior art method; 
         FIG. 3  is a cross-sectional view of a human eyeball further illustrating the prior art method of performing an anterior capsulotomy; 
         FIG. 4  is a front view of a cornea after an anterior capsulotomy is performed according to the prior art method; 
         FIG. 5A  is a perspective view of an exemplary anterior capsulotomy device of the present invention; 
         FIG. 5B  is a perspective view of the underside of the exemplary anterior capsulotomy device of  FIG. 5A ; 
         FIG. 6  is a detailed view of the head of the exemplary anterior capsulotomy device of  FIG. 5A ; 
         FIG. 7  is a detailed view of the cutting element of the exemplary anterior capsulotomy device of  FIG. 5A ; 
         FIG. 8  is a detailed view of the front pulley of the exemplary anterior capsulotomy device of  FIG. 5A ; 
         FIG. 9A  depicts the insertion of the exemplary anterior capsulotomy device of  FIG. 5A  in a limbal incision; 
         FIG. 9B  depicts the process of making an incision in the anterior capsulotomy using the exemplary anterior capsulotomy device of  FIG. 5A ; 
         FIG. 9C  provides another view of the process of making an incision in the anterior capsulotomy using the exemplary anterior capsulotomy device of  FIG. 5A ; and 
         FIG. 9D  depicts the completion of a circular incision in the anterior capsulotomy made using the exemplary anterior capsulotomy device of  FIG. 5A . 
     
    
    
     DETAILED DESCRIPTION 
     This invention is described in preferred embodiments in the following description with reference to the Figures, in which like numbers represent the same or similar elements. Reference throughout this specification to “one embodiment,” “an embodiment,” or similar language means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases “in one embodiment,” “in an embodiment,” and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment. 
     The described features, structures, or characteristics of the invention may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are recited to provide a thorough understanding of embodiments of the invention. One skilled in the relevant art will recognize, however, that the invention may be practiced without one or more of the specific details, or with other methods, components, materials, and so forth. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of the invention. 
     The anterior capsulotomy device of the present invention is illustrated in  FIGS. 5-9 . For illustrative purposes only,  FIGS. 1-4  are provided depicting the prior art methodology. 
     Referring now to  FIG. 1 , a human eye  110  is depicted having an anterior capsule  122  ( FIG. 3 ) exposed through the pupil  128  of the overlying iris  132 , and the sclera  130  ( FIG. 4 ) circumferentially surrounding iris  132 . The cornea  114  overlies anterior capsule  122 , pupil  128 , and iris. Historically, an anterior capsulotomy is performed by making an initial limbal incision  112  in the limbus zone where sclera and iris meet. Alternatively, a clear corneal incision may be made instead. 
     As further depicted in  FIG. 2 , a stylet or needle  116  having a bend  118  such that the head  120  of stylet or needle  116  can be inserted through incision  112 . As can be seen in  FIG. 3 , head  120  of stylet or needle  116  is then used to make small, overlapping tears in anterior capsule  122  to form an opening that can be used to remove the original lens  124  and insert an artificial one. Specifically, the process requires the repeated puncturing of anterior capsule  122  with head  120  of stylet or needle  116  and pulling on the stylet or needle  116 , each time making small tear in the anterior capsule  122 . As shown in  FIG. 4 , this repeated tearing of anterior capsule  122  forms a jagged opening  126  in anterior capsule  122 . 
     With the foregoing background information, the operation and utility of the instrument of the present invention may now be explained and fully understood. Referring now to  FIGS. 5A and 5B , the anterior capsulotomy device  200  of the present invention generally comprises a body  202 , wherein the proximal end is tapered to a head  206  and the distal end acts as a handle portion  204 . Device  200  further comprises a front pulley  210  connected to a cutting element  208 , wherein a portion of front pulley  210  extends through an opening in head  206  to attach to cutting element  208 . 
     Actuator  214  is attached to body  202  such that actuator  214  can be moved by a thumb of a user. Actuator  214  is connected to rear pulley  216  via connecting element  218  ( FIG. 5B  only) such that, when moved, actuator  214  causes rear pulley  216  to rotate. Rear pulley  216  is in turn connected to front pulley  210  by connecting element  212 , such that rotation of rear pulley  216  causes rotation of front pulley  210  and cutting element  208 . 
     In certain embodiments, connecting element comprises a continuous assembly. In certain embodiments, connecting element  212  comprises a cable. In other embodiments, connecting element  212  comprises a belt. In yet other embodiments, connecting element  212  comprises a cord. In certain embodiments, connecting element  212  is formed from a plastic. In other embodiments, connecting element  212  comprises a metal. 
     As depicted in  FIGS. 5A and 5B , actuator  214  is mechanically operated by a thumb of a user. In certain embodiments, actuator  214  is rotated by the user. In other embodiments, actuator  214  is depressed by the user. As will be clear to one of ordinary skill in the art, other types of actuators may be used in place of actuator  214  without departing from the scope of the disclosure. 
     In the illustrated embodiment of  FIG. 5B , body  202  is illustrated as being formed to include groove  220 . In other embodiments, anterior capsulotomy device  200  is not formed to include such a groove. 
     Referring now to  FIGS. 6 and 7 , cutting element  208  is rotatably disposed on head  206  and is attached thereto by front pulley  210 . Member  408  ( FIG. 8 ) is attached to front pulley  210 , and extends through head  206 , and couples to the periphery of aperture  226  ( FIG. 7 ) formed in cutting element  208 , thereby securing cutting element  208  to head  206  while allowing cutting element  208  to rotate with front pulley  210 . 
     In the illustrated embodiments of  FIGS. 6 and 7 , cutting element  208  comprises a first surface  227 , a second surface  229 , and two (2) surgical blades, namely blade  222  and blade  224 , disposed on opposite ends, first end  223  and second end  225 , of cutting element  208  and projecting in a downward direction. In certain embodiments, blades  222  and  224  are formed on cutting element  208  such that cutting element  208  and blades  222  and  224  are a single, contiguous formation. In other embodiments, blades  222  and  224  are disposed on cutting element  208 . 
     In certain embodiments, only the leading edges of blades  222  and  224  are cutting edges. In other embodiments, both the leading and trailing edges of blades  222  and  224  are cutting edges. In such an embodiment, cutting element  208  may be rotated in either a clockwise or counterclockwise direction without affecting the device&#39;s ability to cut the anterior capsulotomy. 
     In certain embodiments, blades  222  and  224  comprise one or more metals. In certain embodiments, blades  222  and  224  comprise the same substance as cutting element  208 . In yet other embodiments, blades  222  and  224  comprise a different substance than cutting element  208 . 
     Turning to  FIG. 8 , the exemplary embodiment of front pulley  210  is shown as having member  408 , which extends through head  206  ( FIGS. 5A ,  5 B, and  6 ) and aperture  226  ( FIG. 7 ) to secure cutting element  208  ( FIGS. 5A ,  5 B,  6 , and  7 ) to head  206 . As will be understood by one of ordinary skill in the art, cutting element  208  may be rotatably attached to head  206  by a means other than front pulley  210  without departing from the scope of the disclosed invention. 
     In certain embodiments, front pulley  210  is formed such that member  408  is substantially cylindrical having one flat side (illustrated in  FIG. 6 ) that abuts a flat side of aperture  226  ( FIG. 7 ). In other embodiments, member  408  and aperture  226  may have other configurations. 
     As illustrated in  FIG. 8 , front pulley  210  additionally comprises sheave  410  formed to include groove  404  disposed between upper flange  402  and lower flange  406  along the circumference of sheave  410 . When connecting cutting element  208  ( FIGS. 5A ,  5 B,  6 , and  7 ) to head  206  ( FIGS. 5A ,  5 B, and  6 ), lower flange  406  rests on top of head  206  while member  408  extends through head  206  and into aperture  226  ( FIG. 7 ). Connecting element  212  ( FIGS. 5A and 5B ) then rests within groove  404 . 
     One feature of the present invention is that the cutting element does not need to make a full 360 degree rotation when actuated by the actuator. Rather, the cutting element can make a circular incision by being rotated about 180 degrees. In certain embodiments, the cutting element comprises two blades, such as blades  222  and  224  ( FIGS. 6 and 7 ), located at opposing ends of the cutting element. In these embodiments, the rotation causes each blade to make a contiguous semicircle incision of a predetermined diameter. In certain embodiments, the cutting element is rotated more than 180 degrees, and therefore, the ends of each semicircle overlap to form a single, circular incision. 
     The amount of the overlap is small to prevent and/or minimize tearing of the anterior capsulotomy in the area of the overlap. As is known by one of ordinary skill in the art, repeatedly cutting the same area of the anterior capsule wall increases the likelihood of tearing. In one embodiment, the arcs cut by each blade of the cutting element overlap by two (2) degrees at either end. In such an embodiment, the cutting element rotates 182 degrees when actuated. 
     As will be clear to one of ordinary skill in the art, by having two opposing surgical blades, the overall sheer stress experienced by the anterior capsule wall is minimal compared to the sheer stress created by a cutting instrument having a single blade. As is known by one of ordinary skill in the art, sheer stress causes deformation of a material by slippage along a plane parallel and/or tangential to the imposed stress. This deformation increases the likelihood that the anterior capsule wall will tear. By utilizing two surgical blades, each moving in opposite directions at the same time and applying the same stress, each blade generates a sheer stress of equal value in opposing directions, thereby theoretically resulting in a net sheer stress of zero. As will be understood by one of ordinary skill in the art, the natural presence of imperfections, varying thickness, etc. will result in an actual net sheer stress that is slightly greater than zero. 
     As will be apparent to one of ordinary skill in the art, the diameter of the cut made by the cutting element is equal to the distance between the two blades. In certain embodiments, this distance is adjustable. In other embodiments, the disclosed anterior capsulotomy device may come in varying sizes, each having a different distance between the blades. Alternatively, the cutting head may be interchangeable; different cutting heads having blades spaced different lengths apart. 
     Turning now to  FIGS. 9A-9D  and  10 , the manner of performing a capsulotomy using the present invention is illustrated. Each of the figures depict a human eye  300  having an anterior capsule  312  exposed through the pupil  304  of the overlying iris  302 , and the sclera  314  circumferentially surrounding iris  302 . The cornea  310  overlies anterior capsule  312 , pupil  304 , and iris  302 . Initially, head  206  of the disclosed device is inserted through a small limbal incision  308  and the cutting element is placed in contact with the anterior capsule wall  304 . In certain embodiments, head  206  is alternatively inserted through a clear corneal incision. By using the actuator (not shown), the cutting element is rotated in the manner depicted in  FIGS. 9B-9D . The blades at ends  208   a  and  208   b  of the cutting element cut opposing arcs  306   a  and  306   b , shown in  FIGS. 9B and 9C . As discussed, the cutting element makes a slightly greater then 180 degree rotation thereby causing arcs  306   a  and  306   b  to overlap, forming circular opening  306  shown in  FIG. 9D . At this point, head  206  is withdrawn and the cut portion of the anterior capsulotomy wall may then be removed through limbal incision  308  using a probe or other device. 
     While the preferred embodiments of the present invention have been illustrated in detail, it should be apparent that modifications and adaptations to those embodiments may occur to one skilled in the art without departing from the scope of the present invention.