Abstract:
A surgical instrument for the deployment of medical devices such as wires and snares wherein one hand manipulates a device including advancing, opening, rotating, closing and retracting.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates surgical instruments and particularly to an instrument for deploying devices such as surgical wire snares and wire baskets in procedures for removal of polyps in the colon, for the retrieval of polyps after polypectomy, and for endoscopic removal of gall stones, stents or foreign bodies. The instrument is useful in a variety of applications wherein a device is manipulated through reciprocal and rotary motions by an output shaft forming part of the instrument. In particular applications, the instrument is useful for imparting reciprocating and rotary motion to snares and baskets used in surgery which are specified for the purpose of illustrating and describing the invention. 
     Wire snares and baskets comprise a sheath usually of Teflon encasing a wire passing through the sheath and extending from both ends thereof. The near end of the sheath is secured to an instrument for moving the wire back and forth in the sheath so as to open and close a snare or basket formed at the far end of the wire beyond the far end of the sheath. An instrument also orients the snare or basket by rotation of a wire within its sheath. In deploying snares and baskets in a surgical procedure, a hand-held instrument is used to orient, to open and to close snare or basket for a specific task. 
     SUMMARY OF THE INVENTION 
     The present invention provides a new and improved instrument for the deployment of surgical devices such as wires and snares wherein one hand manipulates a device including advancing, rotating, and retracting the device to advance the device to an operating site, to rotate for orientation as necessary, and to open and close a wire or snare to accomplish a specific task in a surgical procedure. 
     In a preferred embodiment, the instrument includes an elongate frame with rotatable output shaft within a sheath for deploying a surgical device such as a snare or basket and the like. The frame is in assembly with a finger carriage which is slidably and pivotally mounted on the frame and which includes a mechanism for rotating the output shaft. A thumb finger hole at the top of the frame and finger holes in the finger carriage provide for manipulation of the instrument in one hand to accomplish advance and retraction of the output shaft and basket or snare by linear sliding of the finger carriage with respect to the frame, and rotation of the output shaft by pivoting the carriage side to side with respect to the direction of linear motion. The instrument mechanism is arranged so that the output shaft can be rotated in all positions along the linear advance-retract excursion of the finger carriage and output shaft. 
     A surgical instrument according to the invention provides simultaneous rotation and reciprocation of an output shaft, with smooth and low operational force, and with precise manipulation of a surgical device with one hand. For purposes of illustration and specification, the instrument according to the invention is described with particular reference to surgical snares and baskets. This is done with an understanding that the instrument has utility in both reciprocating and rotating an output shaft and that the shaft and its movement are useful with other devices than baskets and snares. 
     OBJECTS OF THE INVENTION 
     An object of the invention is to provide a new and improved instrument for deploying devices in medical procedures. 
     Another object of the invention is to provide an instrument for one hand deployment of medical devices with simultaneous rotary and reciprocal movement. 
     Another object of the invention is to provide an instrument for manipulating wire baskets and snares having elongate frame with thumb hole, output shaft carried by the frame, and movable finger carriage mounted on the frame for simultaneous rotary and reciprocating manipulation of the output shaft with wire and basket. 
     Other and further objects of the invention will become apparent with an understanding of the following detailed description of the invention or upon employment of the invention in practice. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     A preferred embodiment of the invention has been chosen for detailed description to enable those having ordinary skill in the art to which the invention appertains to readily understand how to construct and use the invention and is shown in the accompanying drawing in which: 
     FIG. 1 a  is a plan view of a surgical instrument according to the invention. 
     FIG. 1 b  is a plan view of a wire basket and sheath for use with the instrument of FIG. 1 a.    
     FIG. 1 c  is a plan view of a wire snare and sheath for use with the instrument of FIG. 1 a.    
     FIG. 2 is a perspective view of a finger carriage in assembly with output shaft of the instrument of FIG.  1 . 
     FIG. 3 is a plan view of a surgical instrument according to the invention showing the finger carriage at forward point of reciprocal excursion. 
     FIG. 4 is a plan view of a surgical instrument of FIG. 1 illustrating interior components of the finger carriage and their connection to the output shaft. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to the drawing, a surgical instrument  10  according to the invention comprises an elongate frame  12 , an output shaft  14 , and a finger carriage  16 . 
     The output shaft  14  represents the wire component of a wire snare  18  or basket  20  with the shaft being encased and freely rotatable within a flexible sheath  22 . In some applications, the output shaft is the wire component of a wire snare or basket, while in other applications the output shaft may be connected to a snare or basket wire. In this description, the output shaft is regarded as the wire. 
     The wire  14  passes through the sheath  22  (shown truncated in FIG. 1 a ) with the near end  22   a  of the sheath affixed to the instrument frame  12  so that the instrument holds the sheath stationary as the instrument finger carriage  16  reciprocates and rotates the shaft within the sheath. The far end  22   b  of sheaths with wire basket  20  and snare  18  are shown in FIGS. 1 b  and  1   c.  The basket and snare are opened and closed as the instrument reciprocates the output shaft or wire, and are oriented as desired as the instrument rotates the shaft. 
     The frame  12  (FIGS. 3,  4 ) comprises a body disposed along axis x-x′ with enlarged finger opening  12   a  at its head end, and a tapered output end  12   b  where the output shaft extends from the instrument through an inner passage or bore  12   c.  The body further includes a central slot  12   d  extending substantially the full length thereof along axis x-x′ defined by side walls  12   e  and end walls  12   f-g.    
     The central slot  12   d  receives a sliding block  24  (FIG. 4) for reciprocating movement within the full length of the slot from retracted position (FIG. 1 a ) and advanced position (FIG.  4 ). The output shaft  14  passes through the sliding block and the near end of the shaft receives a retaining lug  26  for holding the shaft in position at the rear face of the block. The lug is secured to the shaft by suitable means such as a set screw  26   a.  The shaft is free to rotate within the block, and the retaining lug acts as a thrust bearing for moving the shaft rearward as the block moves rearward in its slot. 
     A cylindrical gear  28  is mounted on the output shaft ahead of and abutting the sliding block so that sliding block  24 , output shaft  14  (with retaining lug  26 ) and cylindrical gear  28  slide as a unit back and forth in the central slot  12   d.  The gear is secured by a set screw  28   a  (FIG.  4 ), for example, to the shaft so that the gear and shaft rotate as a unit. The sliding block is constrained against rotation by the slot side walls  12   e.    
     The finger carriage  16  (FIG. 2) comprises a shell  16   a  of over  16   b  and under  16   c  wall members of substantially similar shape defining an open chamber  16   d  containing the subassembly of sliding block  24  with output shaft  14  and cylindrical gear  28 . The finger carriage is pivotally mounted to the sliding block by over 30 and under 32 pivot pins mounted in bores  16   e  aligned on the y-y′ axis. 
     The front face  16   f  of the shell is open and defines a segment of a circle  16   g  (concentric to the pivot axis y-y′) to accommodate the cylindrical gear  28  in position in the shell opening. The upper lip  16   h  of the opening  16   i  contains a gear rack  16   k  in engagement with the shaft gear for rotation of the shaft as the carriage pivots from side to side about the pivot axis y-y′. As best shown in FIG. 4, the gear rack  16   k  intersects the midline of the shaft gear  28  so that rack and gear are always engaged. 
     The lower lip  16   m  (FIG. 2) of the opening defines a plane edge engaging the underside of the cylindrical gear  28  maintaining the gear in engagement with its driving rack. The gear rolls over the lower lip surface through the full excursion of the carriage about the y-y′ pivot axis. 
     The carriage further includes integral finger holes  34   a-b  on either side of the long axis x-x′ for receiving index and middle fingers for rotating the carriage. 
     In use, the instrument is held by thumb and first two fingers in position in thumb, index finger and middle finger holes. By advancing and retracting the index and middle fingers, the carriage slides down and back along the central slot. This reciprocating movement opens and closes a wire snare of basket. 
     By rotating the carriage to the right or left, the output shaft rotates. Rotation of the output shaft enables orientation of the snare or basket as desired. 
     By reason of the design of the instrument, a user is able simultaneously to reciprocate and rotate the output shaft and its snare or basket. 
     Various changes may be made to the structure embodying the principles of the invention. The foregoing embodiments are set forth in an illustrative and not in a limiting sense. The scope of the invention is defined by the claims appended hereto.