Abstract:
An ophthalmic surgical probe having a modular drive assembly and a skin that is removable from the drive assembly. This design simplifies probe manufacturing and provides greater manufacturing flexibility.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention generally pertains to microsurgical instruments. More particularly, but not by way of limitation, the present invention pertains to microsurgical instruments used in posterior segment ophthalmic surgery, such as vitrectomy probes. 
       DESCRIPTION OF THE RELATED ART 
       [0002]    Many microsurgical procedures require precision cutting and/or removal of various body tissues. For example, certain ophthalmic surgical procedures require the cutting and/or removal of the vitreous humor, a transparent jelly-like material that fills the posterior segment of the eye. The vitreous humor, or vitreous, is composed of numerous microscopic fibers that are often attached to the retina. Therefore, cutting and removal of the vitreous must be done with great care to avoid traction on the retina, the separation of the retina from the choroid, a retinal tear, or, in the worst case, cutting and removal of the retina itself. 
         [0003]    The use of microsurgical cutting probes in posterior segment ophthalmic surgery is well known. Such vitrectomy probes are typically inserted via an incision in the sclera near the pars plana. The surgeon may also insert other microsurgical instruments such as a fiber optic illuminator, an infusion cannula, or an aspiration probe during the posterior segment surgery. The surgeon performs the procedure while viewing the eye under a microscope. 
         [0004]    Conventional vitrectomy probes typically include a hollow outer cutting member, a hollow inner cutting member arranged coaxially with and movably disposed within the hollow outer cutting member, and a port extending radially through the outer cutting member near the distal end thereof. Vitreous humor is aspirated into the open port, and the inner member is actuated, closing the port. Upon the closing of the port, cutting surfaces on both the inner and outer cutting members cooperate to cut the vitreous, and the cut vitreous is then aspirated away through the inner cutting member. U.S. Pat. Nos. 4,577,629 (Martinex); 5,019,035 (Missirlian et al.); 4,909,249 (Akkas et al.); 5,176,628 (Charles et al.); 5,047,008 (de Juan et al.); 4,696,298 (Higgins et al.); and 5,733,297 (Wang) all disclose various types of vitrectomy probes, and each of these patents is incorporated herein in its entirety by reference. 
         [0005]    Conventional vitrectomy probes include “guillotine style” probes and rotational probes. A guillotine style probe has an inner cutting member that reciprocates along its longitudinal axis. A rotational probe has an inner cutting member that rotates about is longitudinal axis. In both types of probes, the inner cutting members are actuated using various methods. For example, the inner cutting member can be moved from the open port position to the closed port position by pneumatic pressure against a piston or diaphragm assembly that overcomes a mechanical spring. Upon removal of the pneumatic pressure, the spring returns the inner cutting member from the closed port position to the open port position. As another example, the inner cutting member can be moved from the open port position to the closed port position using a first source of pneumatic pressure, and then can be moved from the closed position to the open port position using a second source of pneumatic pressure. As a further example, the inner cutting member can be electromechanically actuated between the open and closed port positions using a conventional rotating electric motor or a solenoid. U.S. Pat. No. 4,577,629 provides an example of a guillotine style, pneumatic piston/mechanical spring actuated probe. U.S. Pat. Nos. 4,909,249 and 5,019,035 disclose guillotine style, pneumatic diaphragm/mechanical spring actuated probes. U.S. Pat. No. 5,176,628 shows a rotational dual pneumatic drive probe. 
         [0006]    In many conventional vitrectomy probes, the engine and the shell or skin are tied together to yield a functional probe. A disadvantage to this is that the skin serves as both an ergonomic component as well as a part that is responsible for function. Changing between different probe types (i.e. 20, 23, 25 gage probes) requires that the internal features of the skin be changed to accommodate the corresponding functional interfaces such as seal design and tip geometry. This results in less flexibility. 
         [0007]    Therefore, a need exists for an improved vitrectomy probe that exhibits more flexibility. Such flexibility should enable future design and manufacturing flexibility, utilize a number of common components in overall probe design, and be able to convert to multiple gage size probes using the same engine parts. 
       SUMMARY OF THE INVENTION 
       [0008]    The present invention is an ophthalmic surgical having a skin removably coupled to an engine, a needle holder, a needle, and a cutter. The engine has a drive shaft support member and a drive shaft extending axially from the engine. The needle holder has a bushing disposed therein and an opening for removably engaging the drive shaft support member. The needle has a first coupling rigidly coupled thereto. The first coupling is for removably engaging the bushing. The cutter has a second coupling rigidly coupled thereto. The cutter is slidably disposed within the needle, and the second coupling is for removably engaging the drive shaft. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    For a more complete understanding of the present invention, and for further objects and advantages thereof, reference is made to the following description taken in conjunction with the accompanying drawings, in which: 
           [0010]      FIG. 1  is a sectional view of the ophthalmic surgical probe of the present invention; and 
           [0011]      FIG. 2  is an exploded, sectional view of the ophthalmic surgical probe of  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0012]    The preferred embodiments of the present invention and their advantages are best understood by referring to  FIGS. 1-2  of the drawings, like numerals being used for like and corresponding parts of the various drawings. 
         [0013]    Vitrectomy probe  10  consists of engine  12 , shell or skin  14 , needle holder  16 , drive shaft  18 , cutter  20 , and needle  24 . Although the ophthalmic surgical probe of the present invention is described herein in connection with a vitrectomy probe  10 , the present invention is applicable to other ophthalmic or other surgical probes, instruments, and handpieces. Cutter coupling  22  is integrally formed on the proximal end of cutter  20 . Needle coupling  26  is integrally formed on the proximal end of needle  24 . Drive shaft  18  extends axially from engine  12 . Distal end of drive shaft  18  removably engages cutter coupling  22  of cutter  20 . Drive shaft support member  34  removably engages opening  36  of needle holder  16 . Drive shaft support member  34 , drive shaft  18 , and cutter coupling  22  are disposed within needle holder  16 . Bushing  28  within needle holder  16  removably engages needle coupling  26  of needle  24 , such that cutter  20  is slidably disposed within needle  24 . Needle coupling  26 , needle holder  16 , cutter coupling  22 , drive shaft  18 , and drive shaft support member  34  are disposed entirely within skin  14 . Skin  14  contains opening  38  which removably engages body  40  of engine  12 . Needle  24  extends through opening  42  in skin  14 . 
         [0014]    Engine  12  may be any type of engine suitable for driving vitrectomy probe  10 , but is most preferably a pneumatic engine. Drive shaft  18  may be made of any suitable material, but is most preferably stainless steel. Needle  24  and cutter  20  may be made of any material suitable for posterior segment ophthalmic surgery, but are most preferably made from surgical stainless steel. Skin  14 , needle coupling  26 , and cutter coupling  22  are most preferably made from a lightweight material such as aluminum or rigid plastic. 
         [0015]    During manufacturing assembly, the modular design of probe  10  allows a worker to quickly and easily switch between building probes of various needle gages, such as a probe  10  with a 20 gage needle  24 , a 23 gage needle  24 , or a 25 gage needle  24 . More specifically, the ability to quickly attach and remove skin  14  from body  40  of engine  12 , to quickly couple different gages of needle  24  with needle holder  16  and cutter  20  via needle coupling  26  and bushing  28 , and to quickly couple cutter  20  to drive shaft  18  via cutter coupling  22  greatly increases manufacturing flexibility and simplifies the assembly process of probe  10 . 
         [0016]    It is believed that the operation and construction of the present invention will be apparent from the foregoing description. While the apparatus and methods shown or described above have been characterized as being preferred, various changes and modifications may be made therein without departing from the spirit and scope of the invention as defined in the following claims.