SURGICAL CUTTING INSTRUMENT

Abstract: A remotely operable ocular surgical cutting instrument (10), useful, for instance as a knife for a capsulotomy procedure, has a two portion main body (12) with one portion (16) oriented at an angle with respect to the other (14). A turning unit (20) extends through the main instrument body (12), and, to constitute a capsulotomy knife, a cutting blade (22) is mounted on the turning unit (20) at one end of the body (12). During operation, the orientation of cutting edge of the blade (22) with respect to the instrument body (12) is determined by manipulation of the opposite end of the turning unit at the other end of the instrument body (12).

Description: SURGICAL CUTTING INSTRUMENT HELD OF THE INVENTION The present invention relates to surgical cutting instruments, especially small scale, remotely operable surgical knives or scissors, useful for performing a capsulotomy or similar procedure. BACKGROUND OF THE INVENTION A common procedure in ophthalmology to remove cataracts is to use phacoemulsification and suction to remove the affected lens from the eye. This procedure is shown and described, for instance, in Cupler, U.S. Pat. No. 4,002,169, in which access to the lens is achieved through the sclera or limbus, then through the opening in the iris, and finally through the anterior capsular membrane. Although, as shown in Cupler, it may be possible to gain access to the lens and remove it by piercing the anterior capsular membrane, it is more common to remove a circular piece of the membrane by a "capsulotomy" procedure, for example by tearing out a portion of the membrane with a needle and forceps. Alternatively, it is known to free the desired membrane portion with a surgical knife. In this type of procedure it is essential to maintain the cutting edge of the knife so that it is oriented in the proper direction during the entire circular cut. This may be difficult if the cutting instrument is introduced through the single incision in the sclera that is used for the other steps in the cataract removal. One example of a surgical knife appropriate for a capsulotomy is disclosed in Pazandak, U.S. Pat. No.4,708,138, in which a knife blade is attached to an extension handle at a swivel point, the cutting portion of the blade being off center from the swivel point. The knife is directed SUBSTITUTE SHEET by sideways motion of the end of the handle removed from the blade attachment point, and the shape and method of attachment of the cutting blade to the handle cause the blade to orient itself with the cutting edge forward, in the direction of movement of the blade, as long as movement of the blade is continuous. SUMMARY OF THE INVENTION The invention features a remotely operable surgical knife that includes a tubular main body having a primary axis and a turning unit disposed within the main instrument body. A blade is mounted on the turning unit at one end of the main instrument body and is disposed at an angle to the primary instrument body axis. The orientation of the cutting edge of the blade with respect to the main body is determined by movement of the turning unit at the end distal to the blade mounting end. In preferred embodiments of the surgical knife, the tubular main body includes an elongated first portion, open at one end, and a shorter second portion, open at one end and extending from the first portion distal to the open end of the first portion to form an angle greater than 45° to the first portion. The turning unit of the knife includes a turning mechanism in the main body at the jimcture of the first and second portions; a movable rod or wire or other connecting element through the first portion of the main body, which has one end attached to the turning mechanism; and a blade mounting portion in the second portion of the main body and attached to the turning mechanism. The blade is mounted on the blade mounting portion of the turning unit, and movement of the other end of the moveable element causes rotation of the blade about an axis generally aligned with the second portion of the main body. The blade may be discarded and replaced with a fresh blade for each use. Alternatively, the entire surgical knife may be discarded after use. Preferably, the angle between the first and second portions of the main body of the knife is between 80° and 110°, and the knife blade is of a circular configuration. The turning mechanism of the turning unit is preferably a micro gear unit, for example, transversely oriented bevel gears or a rack and pinion unit. Alternatively, the turning mechanism includes a flexible element, such as a silicone rubber, a polyurethane elastomer, or a coiled spring, that has greater flexibility than the movable element portion of the unit. Or the entire turning unit could comprise a rotatable element disposed through the body of the knife. In another embodiment, the body of the instrument and micro gear turning mechanism have similar configurations to those of the surgical knife described above, but the knife blade is replaced by micro dimension scissors, one handle of which is attached directly to the end ~ \ of the turning unit. Orientation of the scissors is maintained along the desired cutting path by rotation of the micro gear turning mechanism, and the scissors are operated to make the desired cut by movement of an additional wire extending from the scissors through the main body of the instrument. Preferably, the turning unit and the scissors control wire are operated by manual control elements in the shape of scissors handles, and portions of the turning unit and the main instrument body are flexible. Because of the small size of the cutting instrument and because movement of the cutting portion is precisely directed from a remote position, a remotely operable surgical cutting instrument according to the invention is easy to use in small incision surgery, where quick entry to and exit from " the site of the operation is required. The cutting portion of the instrument can be directed along the cutting pattern desired at all times during the surgical procedure, whether cutting is made in a continuous process or discontinuously. In the circular or semicircular configuration the knife blade of the surgical knife is readily reversible. The particular advantages of a circular blade are that the knife edge covers a larger surface of the eye and therefore can give better depth control. The cutting instrument is simple and rugged in design. Therefore, numerous embodiments can be inexpensively manufactured from readily available materials and then discarded without incurring any great expense. BRIEF DESCRIPTION OF THE DRAWINGS The character of the invention may be more fully understood by reference to the detailed description and by .the accompanying drawings, in which: Fig. 1 is a side perspective view of a capsulotomy knife according to the invention; Fig. 2 is a side perspective view of another embodiment of a capsulotomy knife according to the invention; Fig. 3 is a side perspective view of another embodiment of a capsulotomy knife according to the invention; Fig. 4 is an axial sectional view of a human eye, showing the invention in use; Fig. 5 is a transverse sectional view of the eye, showing the path taken by a capsulotomy knife according to the invention during use; and Fig. 6 is a side perspective view of an embodiment having micro surgical scissors according to the invention. DESCRIPTION OF THE PREFERRED EMBODIMENT A surgical knife for a capsulotomy procedure must be sized at its cutting end so as to permit insertion into the micro scale surgical field of the eye and yet be large enough at its opposite end to be held comfortably in the hand of the operating surgeon. Preferably, the knife is configured so that it may be introduced through the single incision in the sclera that is used for other steps in cataract removal. Referring first to Fig. 1, a capsulotomy knife 10 has a 15 cm long tubular main body 12 of either plastic or stainless steel, which is open at each end and includes an elongated first portion 14 and a relatively short second portion 16. The elongated portion of--the knife includes a handle 15 of approximately 7 mm in diameter and steps down to a diameter of less than 1 mm at the junction with the second portion. The second portion of the knife extends at a substantial angle to the first portion; in preferred embodiments of the invention, this angle is 80°-110° (preferably 90°). A turning unit 20 extends through the main body of the knife, having a blade 22 mounted thereon at the open end of the second portion of the body and a control knob 24 at the open end of the first portion. Knife blade 22 is attached by any convenient means, and blade mounting portion 28 is journalled for rotation, as shown, or in any other convenient manner to suit the particular implementation. The turning unit itself comprises three sections: first, a movable polytetrafluoroethylene (e.g.. Teflon®) or stainless steel rod 26 through the first portion 14 of the main body, which attaches to the control knob; second, a blade mounting portion 28 through the second portion 16 of the main knife body, to which knife blade 22 is attached; and, third, a micro gear turning mechanism 30 at the juncture of the first and second portions, which connects the movable wire with the blade mounting portion of the unit. As shown in Fig. 1, knife blade 22 is circular and is suspended from blade mount 32. However, numerous other blade configurations, such as semi-circular or triangular as shown in Figs. 2 and 3, are suitable depending on the application. Micro gear mechanism 30 has two edge engaging bevel gears 34, 36 oriented at right angles and supported by bushings 31, 33. Rotation of control knob 24 by a surgeon, and consequent rotation of rod 26 and bevel gear 34, is translated into rotation of bevel gear 36 and knife blade mount pin 32 and, thus, positive controlled rotation of the knife blade itself a full 360°. A typical micro gear, which can be stainless steel or plastic, is about 0.5 mm in diameter, the dimensions of a gear in a small analog watch, and can be machined to have beveled edges at any desired angle. In an alternate configuration 40, shown in Fig. 2, micro gear mechanism 42 comprises a rack gear 44 mounted on the end of movable rod 45 and engaging the teeth of a pinion gear 46, to which knife blade 48 Is attached. Slide control knob 50 is connected to movable rod 45 through a slide opening 52 in main knife body portion 14. As the slide control knob is moved by a surgeon within slide opening 52, passage of the rack gear 44 past the side of pinion gear 46 causes rotation of the gear and, thus, rotation of the knife blade 48. In this Fig. 2 embodiment, part of the main knife body portion 14 extends past the micro gear mechanism to accommodate the movement of rack gear 44. In a third embodiment 60 of the capsulotomy knife, shown in Fig. 3, the turning mechanism 62 of the turning unit is simply an element that is more flexible than the main portion of the unit so that turning unit 20 can accommodate to the shape of the main knife body 12 without kinking. A suitable element to provide this function is a coiled wire spring which is attached at respective ends of moveable rod 26 and the blade mounting portion 28. A flexible material such as a length of silicone rubber. Teflon®, or polyurethane elastomer would also serve the same purpose. The flexible nature of the turning mechanism of embodiment 60 allows rotation of knob 24 to result directly in rotation of the surgical knife blade 64. The operation and the advantages of the present invention will now be readily understood in view of the above description. Figs. 4 and 5 demonstrate the manner in which a capsulotomy knife is used in the capsulotomy procedure on a human eye 70. An incision 72 is made through the sclera and conjunctiva, the cornea is lifted, and the knife 10 is inserted into the eye. The second portion 16 of knife 10 is then passed through the dilated iris 74 and turned so that it is oriented axially of the eye and is positioned above and at a right angle to the general plane of the anterior capsular membrane 76, which overlies the lens 78, the portion of the eye eventually to be removed. δ At this point in the procedure, the knife is lowered and the blade 22 is moved along a circular path 77 defining the section of the anterior capsular membrane to be removed. As shown in Fig. 5, the orientation of the knife blade along the circular path is maintained by rotation of the turning knob 24. This movement serves to rotate blade 22, as described above. The aspect of the blade and its maintenance on the selected path can be facilitated through microscopic observation, as is customary in such surgical procedures. It can be seen, then, that the capsulotomy knife of the invention can be controlled very accurately and easily so that its sharp edge is always directed along the desired cutting path. The simplicity and rugged nature of the knife mean that it can have a long life of useful service. The knife can be made with a blade mounting unit capable of handling interchangeable blades so as to prolong its useful life. Alternatively, a knife made of inexpensive materials can be considered disposable. A knife according to the invention would be useful not only in ocular surgery but also in any kind of arthroscopic or laparoscopic procedure, e.g., in the knee, in the belly for cutting around the gall bladder, or in the brain. For this type of use, the main body of the knife and the moveable rod portion of the turning unit could be made of a flexible plastic. In addition, other surgical cutting instruments for use where precise but remote control is needed, could be fashioned in the same way. For example, as shown in Fig. 6, surgical scissors 80, with a rotatable travel path of more than 270° in either direction, have a tubular main body 12 through which extends turning unit 20 with a micro gear mechanism 30 similar to that for a capsulotomy knife turning mechanism. Micro scissors 82, which are spring loaded with a sheathed coiled spring 83 so as to remain in an open position until urged closed, are stiffly mounted by one scissors handle 84 to the short end of turning unit 20. A flexible wire 88, which is connected by a small ball joint pivot to unattached scissors handle 86, runs from the scissors handle back through the tubular instrument body 12, adjacent to the turning unit. Knurled barrel handle 13 closes off the open end of the long section of the instrument body, and supported at the end of the handle are opposed scissors loop handles 90 and 92. Loop 90 is stiffly connected to the turning unit and extends above a plane through its axis. Loop 92 is connected by pivot 94 to barrel handle 13 and extends below the turning unit plane. Flexible wire 88, extending from the lower scissors handle 86, is attached to lower loop 92 by a hinge 96. To operate the scissors, the surgeon inserts the thumb of the dominant hand into loop 90 and the middle finger into loop 92. A twisting motion of the hand will cause the turning mechanism to rotate, as described before, and will result in positive controlled rotation of the micro scissors. In this manner, the scissors can be kept oriented along a desired cutting path. To provide the scissors cutting action, the surgeon applies pressure from the middle finger on loop 92 and squeezes the loop upwards, towards loop 90. This movement flexes hinge 94 and consequently applies a pulling action to wire 88. Action of the wire on scissors handle 86 then brings the cutting edges of the scissors into juxtaposition. As soon as the pressure on loop 92 is released, action of spring 83 forces scissors handles 84 and 86 apart and restores the scissors to their open configuration. Other embodiments of the invention will be apparent to those skilled in the art from a consideration of this specification or practice of the invention disdosed herein. It is intended that the specification and the examples be considered as exemplary only, with the true scope and spirit of the invention being indicated by the following claims.

Claims: CLAIMS What is daimed is: 1. A remotely operable surgical knife comprising a tubular main body having a primary axis; a turning unit disposed within said main body; and a blade mounted on said turning unit at one end of said main body and disposed at an angle to said primary axis, wherein the orientation of a cutting edge of said blade with respect to said main body is determined by movement of another end of said turning unit, distal to said blade mounting end. 2. A remotely operable surgical knife comprising a tubular main body having a primary axis, said tubular main body comprising an elongated first portion having one end and aligned along said primary axis and a shorter second portion having one end and extending from said first portion to form an angle with respect to said first portion; a a turning unit disposed within said main body, said turning unit comprising a turning mechanism in the main body at the juncture of the first and second portions; a movable element through the first portion of said main body and having one end attached to the turning mechanism; and a blade mounting portion in the second portion of the main body and attached to said turning mechansim; and a Ϊ ade mounted on said blade mounting portion of said turning unit wherein the orientation of a cutting edge of said blade with respect to said main body is determined by movement of a second end of said movable element. 3. The surgical knife of claim 2 wherein said turning mechanism comprises a flexible element having greater flexibility than said movable element. 4. The surgical knife of claim 3 wherein said flexible element is selected from a group consisting of a coiled spring, silicone rubber, polytetrafluoroethylene, and polyurethane elastomer. 5. The surgical knife of claim 2 wherein said turning unit comprises a micro gear. 6. The surgical knife of claim 2 wherein said turning unit comprises a linear rotatable element disposed through the first and second portions of said main body. 7. The surgical knife of daim 2 wherein said angle between said first and second portions of said tubular body is between 80° and 110°. 8. The surgical knife of daim 2 wherein said blade is circular, semi¬ circular, or triangular. 9. The surgical knife of daim 4 wherein said blade is drcular, semi¬ circular, or triangular. 10. A surgical knife of daim 2 wherein said blade is detachably mounted on said blade mounting portion. 11. A surgical knife of daim 4 wherein said blade is detachably mounted on said blade mounting portion. 12. The surgical knife of claim 5 wherein said movable element comprises a second end attached to a control knob at the one end of the first portion; said micro gear comprises first and second transversely oriented bevel gears; and rotation of the control knob causes said rotation of the blade. 13. The surgical knife of claim 5 wherein said movable element comprises a second end attached to a slide control knob; said micro gear comprises rack and pinion elements; and movement of said slide control knob in the direction of said micro gear causes said rotation of said blade. 14. The surgical knife of claim 2 wherein said elongated first portion of said main body and said movable element of said turning unit comprise flexible portions. 15. Remotely operable surgical sdssors comprisiijg: a tubular main body comprising an elongated first portion having one end and a shorter second portion having one end, said second portion extending from said first portion distal to the one end of said first portion to form an angle greater that 45° to said first portion; a turning unit extending through said main body, said turning unit comprising a turning mechanism in the main body at the junction of the first and second portions, said turning mechanism comprising a micro gear, a movable element through the first portion of said main body and having one end attached to the turning mechanism, and a scissors mounting portion in the second portion of the main body; scissors mounted on said sdssors mounting portion, wherein movement of a second end of said moveable element causes rotation of said sdssors about an axis generally aligned with the second portion of the main body; and a sdssors controlling element connected to said sdssors and extending through said main body from said one end of said second portion to said one end of said first portion for controlling operation of said sdssors. 16. The surgical sdssors of daim 15, further comprising a first manually operable control element mounted on said second end of said movable element of said turning unit at said one end of said first portion and a second manually operable control element mounted on said sdssors controlling element at said one end of said first portion. 17. The surgical sdssors of daim 16 wherein said first and second manually operable control elements are configured as scissors handles. 18. The surgical sdssors of daim 15 wherein said elongated first portion of said main body and said movable element of said turning unit comprise flexible portions. 19. A remotely operable surgical knife comprising a tubular main body having a primary axis, said tubular main body comprising an elongated first portion having one end and aligned along said primary axis and a shorter second portion having one end and extending from said first portion to form an angle with respect to said first portion; a turning unit disposed within said main body, said turning unit comprising a turning mechanism in the main body at the juncture of the first and second portions, wherein said turning mechanism comprises a micro gear, wherein said micro gear comprises rack and pinion elements; a movable element through the first portion of said main body and having one end attached to the turning mechanism, wherein said movable element comprises a second end attached to a slide control knob; and a blade mounting portion in the second portion of the main body and attached to said turning mechanism; and a blade mounted on said blade mounting portion of said turning unit, wherein the orientation of a cutting edge of said blade with respect to said main body is determined by movement of said slide control knob in the direction of said micro gear. 20. A manually operable surgical knife, comprising: a housing having a hand-held body portion and an end portion disposed at an angle to the body portion; a manually operable turning unit within said housing; a blade mounting element disposed on said end portion and forming a first end of said turning unit; a surgical blade mounted on said blade mounting element; and a blade positioning element on said body portion and coupled to said turning unit; wherein orientation of said surgical blade about an axis generally aligned with said end portion is determined by manual operation of said blade positioning element. 21. A microsurgical knife comprising: a housing having a hand-held body portion and an end portion disposed at an angle to the body portion; a manually operable turning unit in the housing; a blade mounting element disposed on said end portion and coupled to said turning unit; a surgical blade mounted on said blade mounting element; and a manually operable control element on the housing and coupled to said turning unit; whereby orientation of the surgical blade about an axis generally aligned with said end portion is determined by manipulation of the control element. 22. The microsurgical knife of daim 21 wherein a distal end of said knife comprising at least the blade mounting element and surgical blade are of a small size to fit in a microsurgical indsion. 23. An ophthalmic knife comprising: a hand held body having an end portion disposed at an angle to said body and sized for passage through an interocular incision in a scleric and a conjunctival layer of an eye; a manually operable turning unit in said body; a microsurgical blade at one end of the turning unit adjacent said end portion; and a manually operable control element at a portion of said body distant from said end portion and cooperative with said turning unit; wherein orientation of said surgical blade about an axis generally aligned with said end portion is determined by manual operation of said control element; and wherein a nonlinear, continuous incision is made in the anterior capsular membrane by simultaneous manual positioning of said body and orientation of said surgical blade by manual operation of said control element. 24. A method of performing eye surgery within an interocular incision in the sclera and conjunctiva, between ,the cornea and an anterior capsular membrane, and through an iris, for incising a portion of said anterior capsular membrane, said method comprising: manually inserting an ophthalmic knife, comprising a body portion an end portion disposed at an angle to said body portion and a blade mounted on said end portion, through said interocular incision; manually rotating said blade by manual manipulation of an external control to direct the orientation of said blade with respect to said ophthalmic knife; manually orienting said ophthalmic knife while simultaneously rotating said blade to form a continuous, non-linear incision in said anterior capsular membrane; and manually removing said ophthalmic knife from said indsion. 25. An ophthalmic knife for performing eye surgery within an interocular incision in the sclera and conjunctiva, between the cornea and an anterior capsular membrane, and through an iris, for incising a portion of said anterior capsular membrane, said knife comprising: a hand held body having an end portion disposed at an angle to said body and a blade rotatably disposed at said end portion; a control for manually rotating said blade to direct the orientation of said blade with respect to said body; whereby manually orienting said body while simultaneously manually rotating said control element causes rotation of said blade to provide a continuous, non-linear incision in said anterior capsular membrane.

Inventors: MICHALOS PETER, MICHALOS, PETER
Applicants: MICHALOS PETER, MICHALOS, PETER
Application year: 1993
Main classification: A61B17
IPC codes: A61B17, A61F9