Expandable reamer

Abstract

An expandable reamer for forming a space within a vertebral disc includes a pair of opposing blades which have a expanded state and a retracted state. The blades being pivotally positioned at the distal end of a shaft assembly. A shaft housing being substantially disposed about the shaft assembly. The proximal end of the shaft assembly being operatively engaged by a control device which when rotated allows the blades to be fully retracted for insertion into a pre-bored hole and then to be expanded incrementally until the cavity is bored as desired.

1. An expandable reamer comprising:
 a) an elongated hollow shaft having a proximal and a distal end, the distal end being closed and having a pair of opposing side openings adjacent the closed end;   b) a pair of internal blade members within said hollow shaft;   c) a mechanism for moving said blades from a retracted position within the shaft to a cutting, extended position through said side openings.   
     
     
       2. The expandable reamer of  claim 1  wherein said distal closed end includes an inner, centrally located wedge constructed and arranged to direct the internal blade members out of said side openings when pressed distally. 
     
     
       3. The expandable reamer of  claim 2  wherein said internal blade members each include an elongated shaft having a distal and a proximal end, said proximal end extending up to said blade moving mechanism and a cutting blade on a distal end of said elongated shaft which are completely within said hollow shaft until said elongated shafts are urged distally by said blade moving mechanism. 
     
     
       4. The expandable reamer of  claim 3  wherein said blade moving mechanism is constructed and arranged to engage said proximal end of said blade member elongated shaft and simultaneously move both blades distally or proximally in response to operator movement of said blade moving mechanism. 
     
     
       5. The expandable reamer of  claim 4  wherein said blade moving mechanism includes an adjusting screw which when rotated causes said blades to move distally or proximally in said elongated hollow tube in response to the direction of rotation and degree of rotation. 
     
     
       6. The expandable reamer of  claim 5  further including an indicator mechanism toward the proximal end of said reamer which is visible from the outside of said reamer and shows relative movement of said blades proximally and distally within said hollow shaft to indicate position of the cutting blades. 
     
     
       7. The expandable reamer of  claim 6  wherein said reamer includes a mechanism for applying rotational torque to said hollow shaft such that said cutting blades rotate and provide a cutting operation. 
     
     
       8. The expandable reamer of  claim 7  wherein said cutting blades are constructed and arranged to fully retract within said hollow shaft until said blade moving mechanism urges them out said side openings such that said cutting blades are not in a cutting position until desired. 
     
     
       9. The expandable reamer of  claim 8  wherein said elongated shafts of said blade members are rectangular in cross-section and abut against each other within said hollow shaft to increase torsional rigidity. 
     
     
       10. The expandable reamer of  claim 9  wherein the proximal ends of said elongated shafts of said blade members include notches which engage with an adjustment slide of said blade moving mechanism. 
     
     
       11. The expandable reamer of  claim 10  wherein said adjustment slide is inserted through a side access port which is covered by a locking cover. 
     
     
       12. The expandable reamer of  claim 11  wherein said blade members are spring steel and constructed and arranged to have a slip fit within the hollow shaft such that the blade members may be inserted into said hollow shaft through said side openings while limiting movement of said blade members within said shaft. 
     
     
       13. An expandable reamer comprising:
 a) an elongated shaft having a proximal end and a distal end, a pair of blade members pivotally engaged to the distal end of the elongated shaft, a pair of elongated blade guides positioned immediately adjacent to the elongate shaft, the elongate blade guides each having a guide slot, at least a portion of each of the pair of blade members being operatively engaged to one of the guide slots; 
 b) an elongate hollow tube, the elongate hollow tube being disposed substantially about the elongated shaft and the pair of elongated blade guides, the elongate hollow tube being longitudinally moveable relative to the elongated shaft; 
 c) a handle, the handle having a hollow engagement barrel and at least one griping member extending therefrom, the hollow engagement barrel having a first end engaged to the elongate hollow tube, and a second end having a control knob, the control knob being operatively engaged to the elongate hollow tube, whereby when the control knob is rotated the elongate hollow tube is moved longitudinally relative to the elongated shaft causing the pair of blade members to move between a retracted position and an extended position. 
 
     
     
       14. An expandable reamer comprising:
 a) an elongated shaft having a proximal end and a distal end, a pair of blade members being pivotally engaged to the distal end of the elongated shaft, the distal end of the elongate shaft having a pair of blade slots constructed and arranged to slidingly and removably receive at least a portion of one of the blade members:   b) an elongate hollow tube, the elongate hollow tube being disposed substantially about the elongated shaft, the elongated shaft being longitudinally moveable relative to the elongate hollow tube;   c) a turn wheel, the turn wheel operatively engaged to the proximal end of the elongated shaft and positioned proximal to the elongate hollow tube, whereby when the turn wheel is rotated the elongated shaft is moved longitudinally relative to the elongate hollow tube causing the pair of blade members to move between a retracted position and an extended position.   
     
     
       15. An expandable reamer for use in bone and related tissue in a mammal comprising:
 an elongated hollow body having a proximal end and a distal end, sized and configured to engage bone and related tissue in the mammal;   an elongated blade carrier having a proximal end and a distal end, the blade carrier disposed within the body;   a set of blades pivotally attached proximate the distal end of the blade carriers; the set of blades having at least a first retracted position relative to the body, the body having a maximum cross-sectional diameter transverse to a longitudinal axis of the body that is substantially at least as large as a maximum cross-sectional diameter of the blades in the first retracted position, and a second fully expanded position having a diameter greater than the maximum cross-sectional diameter of the body; and   an manually actuated activation mechanism that moves the set of blades from the first retracted position to the second fully expanded position and any expanded position therebetween.   
     
     
       16. The reamer of claim 15 wherein the body includes a view port. 
     
     
       17. The reamer of claim 15 wherein the blade carrier is linearly movable relative to the body and the body includes indicators that indicate a distance that the blade set is extended from the distal end of the body. 
     
     
       18. The reamer of claim 15 wherein the set of blades includes cam arms and the activation mechanism is a moveable cannulated shaft having linear movement along the body, the moveable cannulated shaft having cam surfaces that engage the cam arms of the set of blades such that the linear movement of the moveable cannulated shaft is translated to pivoting movement of the blade set thereby driving the blade set to the first expanded position. 
     
     
       19. The reamer of claim 18 wherein the cam arms are double sided such that reverse linear movement of the moveable cannulated shaft retracts the blade set into the first retracted position. 
     
     
       20. The reamer of claim 18 wherein the activation mechanism is a blade control knob constrained within the proximal end of the body, the blade control knob having rotational motion that actuates the moveable cannulated shaft such that the linear movement of the moveable cannulated shaft is translated to pivoting movement of the blade set thereby driving the blade set to the expanded position. 
     
     
       21. The reamer of claim 15 wherein the blades extend beyond the distal end of the hollow body. 
     
     
       22. The reamer of claim 15 wherein the blades are pivotally attached at a single pivot point. 
     
     
       23. The reamer of claim 15 wherein each of the blades includes a cutting portion arranged such that substantially all of the cutting portion is outside the maximum cross-sectional diameter of the body when the blades are in the second fully expanded position. 
     
     
       24. An expandable reamer for use in bone and related tissue in a mammal comprising:
 an elongated hollow body having a proximal end and a distal end including means for engaging bone and related tissue in the mammal,   an elongated blade carrier having a proximal end and a distal end, the blade carrier disposed within the body;   a set of blades pivotally attached proximate the distal end of the blade carrier, the set of blades having at least a first retracted position relative to the body, the body having a maximum cross-sectional diameter transverse to a longitudinal axis of the body that is substantially at least as large as a maximum cross-sectional diameter of the blades in the first retracted position, and a second fully expanded position having a diameter greater than the maximum cross-sectional diameter of the body; and   n means for manually moving the set of blades from the first retracted position to the second fully expanded position and any expanded position therebetween.   
     
     
       25. The reamer of claim 24 wherein the body includes a view port. 
     
     
       26. The reamer of claim 24 wherein the blade carrier is linearly movable relative to the back and the body includes indicators that indicate a distance that the blade set is extended from the distal end of the body. 
     
     
       27. The reamer of claim 24 wherein the set of blades includes cam arms and the means for moving the set of blades is a moveable cannulated shaft having linear movement along the body, the moveable cannulated shaft having cam surfaces that engage the cam arms of the set of blades such that the linear movement of the moveable cannulated shaft is translated to pivoting movement of the blade set thereby driving the blade set to the expanded position. 
     
     
       28. The reamer of claim 27 wherein the cam arms are double sided such that reverse linear movement of the moveable cannulated shaft retracts the blade set into the first retracted position. 
     
     
       29. The reamer of claim 27 wherein the means for moving the blade set is a blade control knob constrained within the proximal end of the body, the blade control knob having rotational motion that actuates the moveable cannulated shaft such that the linear movement of the moveable cannulated shaft is translated to pivoting movement of the blade set thereby driving the blade set to the expanded position. 
     
     
       30. The reamer of claim 24 wherein the blades extend beyond the distal end of the hollow body. 
     
     
       31. The reamer of claim 24 wherein the blades are pivotally attached at a single pivot point. 
     
     
       32. The reamer of claim 24 wherein each of the blades includes a cutting portion arranged such that substantially all of the cutting portion is outside the maximum cross-sectional diameter of the body when the blades are in the second fully expanded position. 
     
     
       33. A method for creating a cavity in bone comprising:
 drilling a bore in bone,   inserting an expandable reamer into the bore,   manually actuating an activation mechanism of the reamer that engages a blade carrier within the reamer such that linear motion of the blade carrier drives a blade set pivotally attached to the blade carrier from a first retracted position relative to the body, the body having a maximum cross-sectional diameter transverse to a longitudinal axis of the body that is substantially at least as large as a maximum cross-sectional diameter of the blades in the retracted position to a second fully expanded position having a diameter greater than the maximum cross-sectional diameter of the body and any expanded position therebetween;   contacting the bone with the blade set in the any expanded position; and   rotating the expandable reamer such that the blade set cuts into the bone.   
     
     
       34. The method of claim 33 wherein the blades extend beyond the distal end of the hollow body. 
     
     
       35. An expandable reamer for use in bone and related tissue in a mammal comprising:
 an elongated hollow body having a proximal end and a distal end sized and configured to engage bone and related tissue in the mammal;   at least one shaft operably arranged in a coaxial relation with the hollow body along a longitudinal axis and having a proximal and a distal end;   a set of blades pivotally attached proximate the distal end of the shaft, the set of blades having at least a first retracted position relative to the body, the body having a maximum cross-sectional diameter transverse to a longitudinal axis of the body that is substantially at least as large as a maximum cross-sectional diameter of the blades in the first retracted position, and a second fully expanded position having a diameter greater than the maximum cross-sectional diameter of the body; and   an manually actuated activation mechanism that moves the set of blades from the first retracted position to the second fully expanded position and any expanded position therebetween.   
     
     
       36. The reamer of claim 35 wherein the body includes a view port. 
     
     
       37. The reamer of claim 35 wherein the body includes indicators that indicate a distance that the blade set is extended from the distal end of the body. 
     
     
       38. The reamer of claim 35 wherein the set of blades includes cam arms and the activation mechanism is one of a pair of shafts having linear movement along the body, the shaft having cam surfaces that engage the cam arms of the set of blades such that the linear movement of the shaft is translated to pivoting movement of the blade set thereby driving the blade set to the expanded position. 
     
     
       39. The reamer of claim 38 wherein the cam arms are double sided such that reverse linear movement of the shaft retracts the blade set into the first retracted position. 
     
     
       40. The reamer of claim 38 wherein the activation mechanism is a blade control knob constrained within the proximal end of the body, the blade control knob having rotational motion that actuates one of the pair of shafts such that the linear movement of the shaft is translated to pivoting movement of the blade set thereby driving the blade set to the expanded position. 
     
     
       41. The reamer of claim 35 wherein the blades extend beyond the distal end of the hollow body. 
     
     
       42. The reamer of claim 35 wherein the blades are pivotally attached at a single pivot point. 
     
     
       43. The reamer of claim 35 wherein each of the blades includes a cutting portion arranged such that substantially all of the cutting portion is outside the maximum cross-sectional diameter of the body when the blades are in the second fully expanded position.