Abstract:
An instrument capable of providing large-area shielding within an isolated operating region, such as the eye, while being passable through a small incision in the region through which the instrument must be inserted. For example, an instrument capable of being passed through a typical 3 mm (or smaller) phacoemulsification incision without undue damage to ocular tissue, and which expands to provide large-area shielding, e.g. to occlude a large-diameter (e.g. approx. 6 mm) posterior capsule opening. The surgical instrument includes two or more leaves, the leaves being interconnected by at least one fastener in a manner that causes expansion of a leading or distal portion of the instrument when the following or proximal portions of each leaf are manipulated, whether by a user or through interaction with a wall of the incision.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. application Ser. No. 12/681,654, filed on May 17, 2010, which claims the priority of PCT/US2008/078753, filed on Oct. 3, 2008, which is based on and claims priority to U.S. Provisional Application No. 60/977,867, filed Oct. 5, 2007, the entire contents of which are hereby incorporated fully herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates generally to instruments for use in intraocular surgery, and more particularly to an instrument capable of providing large-area shielding within the eye, yet being passable through a small incision into the eye. 
     DISCUSSION OF RELATED ART 
     Various surgical procedures involve placement of instruments through an incision made in ocular tissue. Exemplary surgical procedures include a phacoemulsification procedure in which a small incision is made in the cornea by a keratome or similar flat-bladed knife. The incision is necessary to permit insertion of instruments into the eye, and to provide access to inner portions of the eye during the surgical procedure. Because the incision damages ocular tissue, it is desirable that the damage be limited, and thus that the incision not exceed about 3 mm in length. In this exemplary procedure, a phacoemulsification probe is then inserted through the incision and is operated to create high-frequency sound waves that break up and/or emulsify the nucleus of the eye&#39;s lens, which is relatively hard tissue, then aspirate that emulsified tissue through the small incision. An irrigation/aspiration instrument may then be inserted through the incision to aspirate the cortex of the lens via suction. A foldable intraocular lens (IOL) may then be inserted through the incision, using an appropriate cartridge and injector, and into the capsular bag of the eye. 
     The wall of the lens capsule is extremely delicate, and posterior capsular rupture is not uncommon. Such rupture carries with it the risk of posterior segment complications and continuing inflammation if cortical and nuclear material released during phacoemulsification of the lens descends to the posterior compartment. Retention of lens material posteriorly also may necessitate subsequent posterior compartment surgery, with its attendant inconvenience and risk. 
     A number of instruments and techniques have been devised to minimize loss of lens material into the posterior compartment during cataract surgery that has been complicated by a tear of the posterior capsule. These include placement of a lens glide through the phacoemulsification incision, placement of viscoelastic material, either through the original incision or through a pars plana (posterior) incision, and placement of instruments, some of which have expanding basket-like protuberances, through a pars plana incision. 
     Insertion of a widely-used Sheets lens glide behind the lens material early after posterior capsular rupture has been detected is a rapid and simple method for attempting to limit loss of lens material into the posterior compartment. Such a Sheets lens glide is a disposable, thin (e.g., 6 mil), small (e.g., 2.8 mm by 30 mm) sterile sheet of polyethylene, such as that manufactured and/or sold by Texas Technology of Austin, Tex., USA under the trademark Cleanfilm, or other plastic material that is generally rectangular in shape, and has a width of no more than the 3 mm (or smaller) incision, to permit it to be inserted through the 3 mm (or smaller) incision made in the ocular tissue. Accordingly, the portion of the lens guide positioned intraocularly cannot effectively prevent lens material from descending to the posterior compartment; phacoemulsified lens material may easily pass beside and behind the 3 mm (or smaller) wide lens guide. Viscoelastic material does not present a solid barrier to posterior migration of lens material, and any technique requiring creating and placing instruments through a pars plana incision entails additional risk of vitreous disruption, retinal tear, choroidal hemorrhage, and vitreous hemorrhage. Furthermore, such techniques do not provide a barrier to prevent substantial loss of lens material backward into the posterior compartment, especially if the pupil is larger than 3 mm in diameter. 
     SUMMARY 
     The present invention provides an instrument capable of providing large-area shielding within the eye, while being passable through a small incision through which the instrument must be inserted into the eye. More specifically, the present invention provides an instrument capable of being passed through a typical 3 mm (or smaller) phacoemulsification incision without undue damage to ocular tissue, and which expands to provide large-area shielding, e.g. to occlude a large-diameter (e.g. approx. 6 mm) posterior capsule opening. 
     In one embodiment, the instrument is specially configured to expand automatically, through the action of insertion through the incision, and to collapse automatically, through the action of withdrawal through the incision. In one embodiment, the surgical instrument includes two or more leaves, the leaves being interconnected by at least one fastener in a manner that causes expansion of a (leading/distal) portion of the instrument when the (following/proximal) portions of each leaf are manipulated by a user. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a plan view of an expandable shield instrument in accordance with an exemplary embodiment of the present invention. 
         FIG. 2  is an exploded view of the leaves of the instrument of  FIG. 1 ;  FIG. 2   a  is an exploded view of another embodiment of the instrument; 
         FIG. 2   b  is an exploded view of yet another embodiment of the instrument. 
         FIG. 3  is a plan view of the instrument of  FIG. 1 , showing the instrument in a collapsed state suitable for insertion into an incision in the eye. 
         FIGS. 4 and 5  are plan views of the instrument of  FIG. 1 , showing the instrument in various expanded states as it is inserted through the incision in the eye. 
         FIG. 6  is a plan view of the instrument of  FIG. 1 , showing the instrument in a fully expanded state in the eye;  FIG. 6   a  is a plan view of the instrument of  FIG. 2   a  in s fully expanded state;  FIG. 6   b  is a plan view of the instrument of  FIG. 2   b  in s fully expanded state 
         FIG. 7  is an exploded view of leaves of an expandable shield instrument in accordance with an alternative embodiment of the present invention; 
         FIG. 8  is a plan view the instrument including the leaves of  FIG. 7 , shown in a collapsed state; 
         FIG. 9  is a plan view the instrument of  FIG. 8 , showing the instrument in a fully expanded state in the eye; 
         FIG. 10  is a plan view of an alternative embodiment of the instrument of  FIG. 8 ; 
         FIGS. 11 and 12  are plan views of another alternative embodiment of the instrument; 
         FIGS. 13 and 14  are plan views of yet another alternative embodiment of the instrument; 
         FIG. 15  is a plan view of an alternative embodiment of the instrument of  FIGS. 11 and 12 ; and 
         FIG. 16  is a plan view of an alternative embodiment of the instrument of  FIGS. 13 and 14 . 
     
    
    
     DETAILED DESCRIPTION 
     The present invention provides an instrument capable of providing large-area shielding within the eye, e.g. a shielding surface having an approximate maximum length and maximum width each greater than 3 mm, and/or providing a shielding area greater than approximately 9 mm 2  and preferably greater than approximately 5 mm in diameter and/or greater than approximately 19 mm 2 . The instrument is specially-configured to provide such large-area shielding and yet to be passable through a small slit-like incision, e.g. 3 mm or less in width, through which the instrument must be inserted into the eye during ocular surgery. 
       FIGS. 1-6  show an exemplary expandable shield instrument  10 . As shown in  FIGS. 1 and 2 , this exemplary instrument includes three leaves  20 ,  30 ,  40  fixedly joined to one another, but in a manner permitting relative rotational movement of the leaves. In this embodiment, each of the leaves defines an opening  22 ,  32 ,  42  toward its respective distal end to allow for insertion of a fastener  50  capable of pivotably joining the leaves, such as a rivet, a plug, post, screw, nut and bolt, etc. At least two of the leaves, namely the outer leaves, have curvilinear outer, edges  26   a ,  26   b ,  46   a ,  46   b , as will be further discussed below. 
     Each leaf  20 ,  30 ,  40  is preferably constructed of a thin, e.g. 6 mil in thickness, flat sheet material that is sterilizable and/or otherwise suitable for insertion in the eye during ocular surgery. Any suitable conventional material may be used, such as polyethylene, such as that manufactured and/or sold by Texas Technology of Austin, Tex., USA under the trademark Cleanfilm. The material should be relatively flexible to limit the likelihood of damage to ocular tissue, but should be rigid enough to permit the leaves to be somewhat self-supporting when grasped manually by their proximal ends  24 ,  34 ,  44  to permit the leaves to be manually manipulated during a procedure, and to act as a shield to prevent posterior migration of nuclear fragments, etc. In certain embodiments, the proximal end  24 ,  44  of each outer leaf  20 ,  40  includes a substantially straight-edged portion alignable with a substantially straight-edged portion of the central leaf  30  with the shield is fully expanded, such as the substantially straight-edged and aligned proximal region  24 ,  34 ,  44  of each leaf. 
       FIGS. 2-6  show the instrument  10  in various states assumed during insertion of the instrument into the eye, which is shown diagrammatically as eye tissue  200  having an exemplary phacoemulsification (or other) incision  210 , the eye and incision being shown in cross-section for illustrative purposes. The exemplary incision has a width W i , as shown in  FIGS. 3-6 , of approximately 3 mm or less, as is typical of an exemplary incision made by a keratome in a phacoemulsification procedure. As best shown in  FIG. 3 , which shows the instrument in a collapsed state, the leading end  12  of the instrument  10  is configurable to a collapsed state in which the leading end has a width approximately equal to, and preferably less than, the width W i  of the incision through which it is intended to be passed, so that the instrument may be passed into the eye with little or no damage to the ocular tissue surrounding the incision. 
     As the instrument  10  is advanced further into the eye, as shown in  FIG. 4 , the outer leaves  20 ,  40  may be manually grasped and pivoted about the fastener  50  to expand the leaves to define a shielding portion  14  within the eye, e.g., within the anterior chamber of the eye. Additionally, the leaves may be manipulated to maintain an outer boundary B defined by the overlapping leaves, adjacent the incision in the eye tissue, at a width approximately equal to, and preferably less than, the width W i  of the incision. This minimizes damage to the ocular tissue surrounding the incision resulting from passing of the instrument therethrough. 
     It should be noted that in this embodiment, the outer boundary B is a “sliding boundary”, in that is a narrow portion that moves longitudinally relative to the longitudinal axis of the central leaf  30  from a point near the fastener  50 , toward a point far from the fastener  50  as the outer leaves  20 ,  40  are pivoted relative to one another during insertion of the instrument into the eye. This sliding boundary permits maintenance of a minimum width of the instrument adjacent the incision  210  that approximates the incision width, and thus minimizes damage to eye tissue during insertion of the device through the incision. See  FIG. 5  showing further insertion of the instrument  10  into the eye. 
     When the instrument is fully inserted into the eye, as shown in  FIG. 6 , the shield portion  12  is fully expanded to provide a maximum area of the shielding surface. It will be noted that the leaves  20 ,  30 ,  40  may overlap to provide a continuous (or substantially continuous) shielding surface area. Accordingly, it will be noted that the maximum width W s  of the shield portion  12  within the eye can be manipulated to far exceed the width W i  of the incision through which the instrument must be passed, as shown in  FIG. 6 . For example, the shielding portion  12  may have an approximate maximum length and maximum width each greater than 3 mm, and/or providing a shielding area greater than approximately 9 mm 2 ′ and preferably greater than approximately 5 mm in diameter and/or greater than approximately 19 mm 2 , and thus be suitable for occluding the posterior capsular opening, for example, which is typically about 6 mm in diameter. 
     It should be noted that it is possible to advance the instrument directly into the eye by manually grasping the central leaf  30  alone, and pushing the instrument through the incision and into the anterior compartment of the eye. In this insertion method, the eye tissue adjacent the incision defines a “bottleneck”, and acts as a follower in a cam/follower arrangement, and causes the curvilinear (cam) surfaces of the outer leaves  20 ,  40  to pivot to expand the shield portion  12  as it is advanced into the eye. Similarly, the central leaf  30  alone may be grasped as the instrument is withdrawn from the eye, and the leaves will move automatically as the curvilinear surfaces  26   a ,  46   a  ride over the eye tissue adjacent the incision, to automatically move the leaves, such as into the collapsed state and in any case having the minimum width of the tool adjacent the incision to permit removal from the eye. 
       FIGS. 7-9  show an expandable shield instrument in accordance with an alternative embodiment of the present invention. The individual leaves  20 ,  30 ,  40  define openings  22 ,  32 ,  42  at which they may be interconnected or joined by a fastener  50 , etc, as best shown in  FIGS. 7 and 8 . It should be noted that fewer or more than three leaves may be employed, as desired. In this embodiment, the leaves are generally rectangular in overall shape, and may be aligned to substantially overlap to define a collapsed state having a width less than a width W i  of the incision in the eye through which it must be passed, as best shown in  FIG. 8 . In this embodiment, however, the outer edges of the leaves define reentrant shoulders  28 ,  38 ,  48  at which the width of each leaf is narrowed, as best shown in  FIG. 7 . The shoulders are positioned adjacent the fastener  50 , as best shown in  FIGS. 8 and 9 . This permits the instrument  10  to be inserted into the eye to a point at which the shoulders  28 ,  38 ,  48  span the incision in the eye tissue, as shown in  FIG. 9 . The provides clearance to limit damage to ocular tissue when the distal ends of the leaves are spread apart in fan-like fashion to provide an expanded shield portion  12  within the eye  200 , as best shown in  FIG. 9 . The distal ends of the leaves may be spread in this manner by manually manipulating the proximal ends  24 ,  34 ,  44  of the leaves  20 ,  30 ,  40 , which remain outside of the eye and accessible to the eye surgeon. The leaves may be collapsed and withdrawn as desired, in a similar manner. 
       FIG. 10  is a plan view of an alternative embodiment of the instrument of  FIG. 8 . In this embodiment, the leaves  20 ,  30 ,  40  need not include an opening for accommodating a fastener  50 . Instead, an elastomeric or other constrictive band  52 , may be placed around the leaves in lieu of another fastener such as a rivet to provide scissor-like pivoting action of the leaves. This device may be used, inter alia, in an eye surgery by insertion through incision in a manner similar to that described above with reference to the embodiment of  FIGS. 7-9 . 
       FIGS. 11 and 12  are plan views of another alternative embodiment of the instrument. In this embodiment, a pair of leaves  20 ,  30  support a relatively smooth continuous membrane  60 , such as a thin sheet of polyethylene, providing a shielding area approximately 7 mm in diameter. The membrane  60  is sufficiently thin and flexible to be gathered between the leaves  20 ,  30 , or wrapped around one or both of the leaves, to provide a collapsed state in which an outer width of the instrument is approximately equal to or less than a width W i  of the incision through which it is intended to be passed, e.g. 3 mm or less. After insertion into the eye, the leaves may be separated to extend the membrane  60  therebetween to provide a shield portion  12  within the eye. For illustrative purposes, the instrument is shown in a partially collapsed state in  FIG. 11 , and in a partially expanded state in  FIG. 12 . 
       FIGS. 13 and 14  are plan views of yet another alternative embodiment of the instrument  10 . This embodiment is similar in structure and in use to that shown in  FIGS. 11 and 12 . However, in this embodiment, the membrane  60  includes accordion-style pleats  62  to facilitate collapsing of the instrument. For illustrative purposes, the instrument is shown in a collapsed state in  FIG. 13 , and in a partially expanded state in  FIG. 14 . 
       FIG. 15  is a plan view of an alternative embodiment of the instrument of  FIGS. 11 and 12 . This embodiment is similar in structure and use to that shown in  FIGS. 11 and 12 , but further includes a fastener  50  joining the leaves  20 ,  30  so that they may pivot relative to one another. A rivet, as shown in  FIG. 15 , or similar fastener may be used for this purpose. Optionally, the leaves  20 ,  30  may include shoulders  28 ,  38  similar to those shown in  FIGS. 7-10 . The instrument may be positioned in collapsed and expanded states by manually manipulating the proximal ends  24 ,  34  of the leaves  20 ,  30  in a manner similar to that described above. 
       FIG. 16  is a plan view of an alternative embodiment of the instrument of  FIGS. 13 and 14 . This embodiment is similar in structure and use to that shown in  FIGS. 13 and 14 , but further includes a fastener joining the leaves  20 ,  30  so that they may pivot relative to one another. An elastic or inelastic constrictive band  52 , as shown in  FIG. 16 , or similar fastener  50  such as a rivet, may be used for this purpose. Optionally, the leaves  20 ,  30  may include shoulders  28 ,  38  similar to those shown in  FIGS. 7-10 . The instrument may be positioned in collapsed and expanded states by manually manipulating the proximal ends  24 ,  34  of the leaves  20 ,  30  in a manner similar to that described above. 
     Although use of the instrument is described above for illustrative purposes with respect to use in a phacoemulsification procedure, it is suitable for a variety of uses. Additional exemplary uses of the instrument include, but are not limited to any invasive surgical procedure requiring a shielding or partitioning device through an incision smaller than a desired shield or partition distal end. 
     In posterior capsular rupture with remaining nuclear fragments, the instrument may be placed behind the fragments to prevent their posterior dislocation during the attempts at their removal; 
     When inserting an IOL into the ciliary sulcus in the presence of a capsular rupture, the instrument may be used to guide the lens safely over the capsular opening and into the sulcus; and 
     If an IOL is determined to have inadequate capsular support (due, for example, to the size of a capsular tear or zonular dehiscence), the instrument may be used to guide the IOL out of the eye, providing a barrier to the posterior compartment. 
     While there have been described herein the principles of the invention, it is to be understood by those skilled in the art that this description is made only by way of example and not as a limitation to the scope of the invention.