Abstract:
A handle for endoscopic surgical instruments with an elongated thumb loop optimized for providing support and driving force in endoscopic surgery.

Description:
BACKGROUND OF THE INVENTION 
     The field of the invention is that of micro-instrumentation, that is, articulating, hand-held, instruments used in micro-surgery and like applications, for cutting or punching out tissue. The invention is particularly advantageous for use with such instrumentation. 
     FIG. 1 shows a typical endoscopic instrument with tubular extension 30 of 4-10 inches long and 3-5 mm in diameter connecting an effector tip assembly 40, which may be a grasper, a punch, a cutter or some combination, with a stationary handle 10 and an actuating handle 20. Typically, the stationary handle provides a thumb loop 15 angled downward from a portion 17 in which the tubular extension 30. Fitting portion 17 provides for a pivot 18 for actuating handle 20 and houses a linkage to manipulate effector 40 by movement of actuator handle 20. The instrument is manipulated with the operator&#39;s thumb in the thumb loop and one or more other fingers moving the actuator handle. In the prior art, the thumb loop 15 is generally of a circular or elliptical shape of a size adapted for a thumb to engage at a generally perpendicular angle. 
     SUMMARY OF THE INVENTION 
     Objectives of the present invention include the provision of an improved thumb loop, for use with an endoscopic instrument, that provides optimal comfort to operators with diverse thicknesses of their thumbs engaging the loop at a variety of angles and allowing such operators to support and manipulate tubular extension 30 and effector tip 40 optimally. The invention includes a handle, for grasping by a human thumb, angled downward from a fitting portion wherein the inside radius of the top portion of the thumb loop is smaller than the inside radius of the bottom portion of the thumb loop, defining a pear-shaped inner surface of the loop. An advantage of the invention is to allow the operator to move the effector assembly firmly along the axis of the effector assembly (with or without the extension), for example, through tissue inside a patient, with the operator&#39;s thumb firmly braced along a portion of the pear-shaped surface conforming in width to the operator&#39;s thumb. 
     The elongated loop also allows for comfortable &#34;palming&#34; of the instrument where the palm engages the outside portion of the loop and the fingers engage the other handle. This use allows the greater exertion of forward force using the palm rather than just the thumb. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     FIG. 1 shows a typical endoscopic surgical instrument with a prior art thumb loop. 
     FIG. 2 shows the elongated thumb loop of the invention as part of an endoscopic surgical instrument. 
     FIG. 3 shows details of the handle with the elongated thumb loop of the invention. 
     FIG. 3A shows details of alternative elongated thumb loop as an alternative embodiment of the invention. 
    
    
     DETAILED DESCRIPTION 
     FIG. 2 shows an endoscopic instrument with the elongated thumb loop 100. FIG. 3 shows details of the handle for an endoscopic instrument with a preferred embodiment of the thumb loop 100. In this embodiment, shank 160 is angled approximately 45° downwards 150 from the axis of fitting portion 170. Thumb loop 100 is attached to shank 160 at a position distal from the fitting portion 170 and further angled approximately 19° downwards 140 from the shank 160 to the centerline or axis 145 of the loop. The inner radius 110 of the top portion of the loop is approximately 0.250 inches, and inner radius 120 of the bottom portion of the loop is approximately 0.425 inches, with a separation 130 of their centers of approximately 0.945 inches, thereby forming a pear-shaped inner surface. It has been found that operators with diverse thicknesses of their thumbs can operate an endoscopic instrument with this thumb loop 100 comfortably and optimally with their thumbs engaging the inside surface of loop 100 at various angles in a region corresponding to the thickness of their thumbs. Shank 160 and its extension by the outside surface of loop 100 provide a convenient surface for comfortably &#34;palming&#34; the instrument. 
     FIG. 3 shows a handle for an endoscopic instrument with an alternative embodiment of the thumb loop 100&#39;. In this embodiment, shank 160 is again angled approximately 45° downwards 150 from the axis of fitting portion 170. Thumb loop 100&#39; is attached to shank 160 further angled approximately 26° downwards 140&#39; from the shank 160 to the loop axis 145&#39;. The inner radius 110&#39; of the top portion of the loop is approximately 0.175 inches, and inner radius 120&#39; of the bottom portion of the loop is approximately 0.400 inches, with a separation 130&#39; of their centers of approximately 0.925 inches. 
     It should be understood that some of the stated dimensions may be varied without losing the advantage of the invention, and the loop may be part of a movable handle, rather than a handle stationary relative to the tubular extension. Other configurations are possible, with the advantage that the operator&#39;s thumb is firmly braced against the narrowest portion of a pear-shaped inner surface of the thumb loop when exerting force along the axis of the effector, that is, the narrowest end of the pear-shaped inner surface is in the direction of the exertion of force.