Rongeur with vented t-slide and/or increased strength

Abstract

A rongeur comprising: a bottom shaft comprising a proximal end and a distal end and a substantially flat upper surface extending along at least a portion of the bottom shaft, the distal end terminating in a footplate; a top shaft comprising a proximal end and a distal end and a substantially flat bottom surface extending along at least a portion of the top shaft; wherein the bottom shaft comprises a groove characterized by a wider proximal recess and a narrower distal recess, the distal recess comprising an undercut; wherein the top shaft comprises a tongue characterized by a crossbar connected to the bottom surface of the top shaft by a vertical riser; wherein at least a portion of the flat bottom surface of the top shaft rests on at least a portion of the flat upper surface of the bottom shaft and the tongue is slidably disposed in the groove so that when the top shaft is moved distally relative to the bottom shaft, the tongue slides from the wider proximal recess into the narrower distal recess; and further wherein the top shaft comprises at least one passageway for admitting air into the portion of the wider proximal recess vacated by the tongue.

What is claimed is: 
     
         1 . A rongeur comprising:
 a bottom shaft comprising a proximal end and a distal end and a substantially flat upper surface extending along at least a portion of the bottom shaft, the distal end terminating in a footplate;   a top shaft comprising a proximal end and a distal end and a substantially flat bottom surface extending along at least a portion of the top shaft;   wherein the bottom shaft comprises a groove characterized by a wider proximal recess and a narrower distal recess, the distal recess comprising an undercut;   wherein the top shaft comprises a tongue characterized by a crossbar connected to the bottom surface of the top shaft by a vertical riser;   wherein at least a portion of the flat bottom surface of the top shaft rests on at least a portion of the flat upper surface of the bottom shaft and the tongue is slidably disposed in the groove so that when the top shaft is moved distally relative to the bottom shaft, the tongue slides from the wider proximal recess into the narrower distal recess;   and further wherein the top shaft comprises at least one passageway for admitting air into the portion of the wider proximal recess vacated by the tongue.   
     
     
         2 . A rongeur according to  claim 1  wherein the at least one passageway extends vertically through the top shaft. 
     
     
         3 . A rongeur according to  claim 2  wherein the at least one passageway comprises a longitudinal slit. 
     
     
         4 . A rongeur according to  claim 3  wherein the distal and proximal ends of the longitudinal slit comprise arcuate surfaces. 
     
     
         5 . A rongeur according to  claim 1  wherein the at least one passageway is formed in a side wall of the top shaft. 
     
     
         6 . A rongeur according to  claim 5  wherein the at least one passageway extends across only a portion of the full width of the top shaft. 
     
     
         7 . A rongeur according to  claim 6  wherein the at least one passageway comprises a second passageway formed in the side wall of the top shaft. 
     
     
         8 . A rongeur according to  claim 7  wherein the two passageways are offset from one another. 
     
     
         9 . A rongeur according to  claim 8  wherein the two passageways are separated by a midline ridge. 
     
     
         10 . A rongeur according to  claim 9  wherein the outboard surfaces of the midline ridge comprise arcuate surfaces. 
     
     
         11 . A rongeur according to  claim 5  wherein the at least one passageway extends across the complete width of the top shaft. 
     
     
         12 . A rongeur according to  claim 1  wherein the at least one passageway comprises a longitudinal slit extending vertically through the top shaft and a passageway formed in the side wall of the top shaft. 
     
     
         13 . A rongeur according to  claim 1  wherein the crossbar is formed with square edges. 
     
     
         14 . A rongeur according to  claim 5  wherein the undercut is formed with square edges. 
     
     
         15 . A rongeur according to  claim 1  wherein the bottom of the crossbar is formed with rounded edges. 
     
     
         16 . A rongeur according to  claim 15  wherein the floor of the undercut is formed with rounded edges. 
     
     
         17 . A rongeur according to  claim 15  wherein the top of the crossbar is formed with square edges. 
     
     
         18 . A rongeur according to  claim 17  wherein the ceiling of the undercut is formed with square edges. 
     
     
         19 . A rongeur comprising:
 a bottom shaft comprising a proximal end and a distal end, and an upper surface having a groove formed therein, the distal end terminating in a footplate;   a top shaft comprising a proximal end and a distal end, and a bottom surface having a tongue projecting downwardly therefrom;   the bottom surface of the top shaft being slidably disposed on the upper surface of the bottom shaft, and the tongue being slidably disposed in the groove, so that when the top shaft is moved distally relative to the bottom shaft, the tongue slides distally within the groove;   and further wherein the top shaft comprises at least one passageway for admitting air into the portion of the groove vacated by the tongue, whereby to eliminate the potential to generate suction force in the portion of the groove vacated by the tongue as the top shaft moves distally.   
     
     
         20 . A rongeur according to  claim 19  wherein the tongue-and-groove collectively form a T-slide connection. 
     
     
         21 . A rongeur according to  claim 19  wherein the at least one passageway extends vertically through the height of the top shaft. 
     
     
         22 . A rongeur according to  claim 21  wherein the at least one passageway comprises a longitudinal slit. 
     
     
         23 . A rongeur according to  claim 19  wherein the at least one passageway is formed in the bottom surface of the top shaft and opens on a side wall of the top shaft. 
     
     
         24 . A rongeur comprising:
 a bottom shaft comprising a proximal end and a distal end and a substantially flat upper surface extending along at least a portion of the bottom shaft, the distal end terminating in a footplate;   a top shaft comprising a proximal end and a distal end and a substantially flat bottom surface extending along at least a portion of the top shaft;   wherein the bottom shaft comprises a groove characterized by a wider proximal recess and a narrower distal recess, the distal recess comprising an undercut;   wherein the top shaft comprises a tongue characterized by a crossbar connected to the bottom surface of the top shaft by a vertical riser;   wherein at least a portion of the flat bottom surface of the top shaft rests on at least a portion of the flat upper surface of the bottom shaft and the tongue is slidably disposed in the groove so that when the top shaft is moved distally relative to the bottom shaft, the tongue slides from the wider proximal recess into the narrower distal recess;   and further wherein the floor of the undercut is formed with rounded edges and the bottom of the crossbar is formed with rounded edges.