Rod reducer instruments and methods

Abstract

Rod reducers for use in orthopedic surgery are disclosed that include a fastener engaging member and a reducing member coupled together by an actuator assembly. The fastener engaging member can be secured to a fastener engaged to bone or tissue of the patient. The actuator assembly moves the reducing member such that its distal end contacts a rod and moves it toward the fastener.

What is claimed is: 
     
       1. A surgical instrument for reducing a rod toward a bone fastener, comprising:
 a fastener engaging member extending between a proximal end and a distal end, a distal portion of said fastener engaging member being adapted to receive a portion of the rod therein and being further adapted to engage the bone fastener; 
 a reducing member movably disposed about said fastener engaging member, said reducing member having a distal end and a longitudinal axis oriented in its direction of movement; and 
 an actuator assembly pivotally coupled to said fastener engaging member and pivotally coupled to said reducing member, said actuator comprising a first arm and a second arm, wherein said actuator assembly is operable to move said reducing member distally with respect to said fastener engaging member when proximal ends of said first and second arms are biased together, whereby, with biasing together of said first and second arms, said distal end of said reducing member contacts the rod to move the rod distally, relative to said fastener engaging member, toward the bone fastener, 
 wherein a plane along which said first and second arms move is offset from the longitudinal axis. 
 
     
     
       2. The instrument of  claim 1 , wherein said actuator assembly includes a lateral offset to position a proximal portion of said actuator assembly is offset away from a proximal end opening of a passage extending through said fastener engaging member. 
     
     
       3. The instrument of  claim 1 , wherein said actuator assembly includes a first arm is pivotally coupled to a said second arm. 
     
     
       4. The instrument of  claim 3 , wherein:
 said first arm includes a joint between a proximal end and a distal end of said first arm, said joint defining a proximal portion and a distal portion of said first arm; 
 said second arm includes a joint between a proximal end and a distal end of said second arm, said joint defining a proximal portion and a distal portion of said second arm; and 
 said proximal portion of said first arm and said proximal portion of said second arm are each pivotal about a respective one of said joints to orient said proximal portions transversely to said distal portions. 
 
     
     
       5. The instrument of  claim 1 , wherein said actuator assembly includes a locking mechanism to hold said reducing member in a reduced position. 
     
     
       6. The instrument of  claim 1 , wherein said actuator assembly is spring biased to a reducing member retracted position. 
     
     
       7. The instrument of  claim 1 , wherein said fastener engaging member includes a pair of flex arms extending proximally from said distal end thereof. 
     
     
       8. The instrument of  claim 7 , wherein said fastener engaging member includes a prong at the distal end of each of said flex arms, each of said prongs defining a channel for receiving the rod therein. 
     
     
       9. The instrument of  claim 8 , wherein said reducing member is positionable over at least a portion of said prongs. 
     
     
       10. The instrument of  claim 7 , wherein said fastener engaging member includes a pair of elongated slots extending between said flex arms opening at said distal end. 
     
     
       11. The instrument of  claim 10 , wherein said reducing member includes at least one slot through a sidewall thereof in communication with one of said elongated slots of said fastener engaging member. 
     
     
       12. The instrument of  claim 1 , wherein said fastener engaging member and said reducing member are reciprocally slidably coupled. 
     
     
       13. The instrument of  claim 1 , wherein said reducing member and said fastener engaging member each include a generally circular cross-section. 
     
     
       14. The instrument of  claim 1 , wherein:
 said fastener engaging member has a longitudinal axis extending proximally and distally therethrough; and 
 said reducing member has a longitudinal axis extending proximally and distally therethrough, said longitudinal axis of said reducing member being generally positioned along said longitudinal axis of said fastener engaging member. 
 
     
     
       15. The instrument of  claim 1 , wherein said actuator assembly includes:
 a first link having a distal end pivotally coupled to a first side of said reducing member; 
 a first pivot arm having a distal end pivotally coupled to a proximal end of said first link, said first pivot arm having a medially extending connector pivotally coupled to said fastener engaging member; 
 a first arm having a distal end pivotally coupled to a proximal end of said first pivot arm, said first arm having a proximal portion extending proximally from a medially extending connector; 
 a second link having a distal end pivotally coupled to a second side of said reducing member opposite said first side; 
 a second pivot arm having a distal end pivotally coupled to a proximal end of said second link, said second pivot arm having a medially extending connector pivotally coupled to said medially extending connector of said first pivot arm and also pivotally coupled to said fastener engaging member; and 
 a second arm having a medially extending connector pivotally coupled to said medially extending connector of said first arm, said second arm having a distal end pivotally coupled to a proximal end of said second pivot arm, said second arm further having a proximal portion extending proximally of said medially extending connector of said second arm. 
 
     
     
       16. The instrument of  claim 1 , wherein said actuator assembly includes:
 a first link having a distal end pivotally coupled to said reducing member; 
 a first arm having a distal end pivotally coupled to said fastener engaging member, said first arm extending to a proximal end, said first arm further being pivotally coupled between said proximal and distal ends to a proximal end of said first link; 
 a second link having a distal end pivotally coupled to said reducing member opposite said first link; and 
 a second arm having a distal end pivotally coupled to said fastener engaging member opposite said first arm, said second arm extending to a proximal end and being pivotally coupled between said proximal and distal ends to a proximal end of said second link. 
 
     
     
       17. The instrument of  claim 16 , further comprising a stop member at said proximal end of said fastener engaging member to limit proximal movement of said reducing member. 
     
     
       18. A surgical instrument for reducing a rod toward a bone fastener, comprising:
 a fastener engaging member having a passage extending between a proximal end and a distal end, a distal portion of said fastener engaging member being adapted to receive a portion of the rod therein and being further adapted to engage the bone fastener, the passage having a longitudinal axis; 
 a reducing member movably disposed with respect to said fastener engaging member, said reducing member having a distal end; 
 an actuator assembly coupled between said fastener engaging member and said reducing member and, said actuator including a proximal portion, extending proximally of said reducing member and said fastener engaging member, a first arm and a second arm, wherein:
 said actuator assembly includes a lateral offset portion to locate said proximal portion of said actuator assembly away from a proximal end opening of said passage of said fastener engaging member; and 
 said actuator assembly is operable to move said reducing member distally with respect to said fastener engaging member whereby said distal end of said reducing member contacts the rod to move the rod toward the bone fastener; and 
 
 proximal ends of said first and second arms are biased together to move said reducing member distally relative to said fastener engaging member to move the rod toward the bone fastener; and 
 a plane along which said first and second arms move is offset from the longitudinal axis. 
 
     
     
       19. The instrument of  claim 18 , wherein said reducing member is positioned about said fastener engaging member and slidable with respect thereto in response to operation of said actuator assembly. 
     
     
       20. The instrument of  claim 19 , wherein said distal end of said fastener engaging member includes a pair of prongs forming a rod passage. 
     
     
       21. The instrument of  claim 20 , wherein said reducing member and said distal end of said fastener engaging member are configured such that said reducing member exerts inward pressure on at least one of said prongs when said reducing member is positioned over said prongs. 
     
     
       22. The instrument of  claim 18 , wherein:
 said fastener engaging member has a longitudinal axis extending proximally and distally therethrough; and 
 said reducing member has a longitudinal axis extending proximally and distally therethrough, said longitudinal axis of said reducing member being generally positioned along said longitudinal axis of said fastener engaging member. 
 
     
     
       23. The instrument of  claim 18 , wherein said actuator assembly includes:
 a first link having a distal end pivotally coupled to a first side of said reducing member; 
 a first pivot arm having a distal end pivotally coupled to a proximal end of said first link, said first pivot arm having a medially extending connector pivotally coupled to said fastener engaging member; 
 a first arm having a distal end pivotally coupled to a proximal end of said first pivot arm, said first arm having a medially extending connector; 
 a second link having a distal end pivotally coupled to a second side of said reducing member opposite said first side; 
 a second pivot arm having a distal end pivotally coupled to a proximal end of said second link, said second pivot arm having a medially extending connector pivotally coupled to said medially extending connector of said first pivot arm and also pivotally coupled to said fastener engaging member; and 
 a second arm having a medially extending connector pivotally coupled to said medially extending connector of said first arm, said second arm having a distal end pivotally coupled to a proximal end of said second pivot arm. 
 
     
     
       24. The instrument of  claim 18 , wherein said actuator assembly includes:
 a first link having a distal end pivotally coupled to said reducing member; 
 a first arm having a distal end pivotally coupled to said fastener engaging member, said first arm extending to a proximal end, said first arm further being pivotally coupled between said proximal and distal ends to a proximal end of said first link; 
 a second link having a distal end pivotally coupled to said reducing member opposite said first link; and 
 a second arm having a distal end pivotally coupled to said fastener engaging member opposite said first arm, said second arm extending to a proximal end and being pivotally coupled between said proximal and distal ends to a proximal end of said second link. 
 
     
     
       25. The instrument of  claim 18 , wherein said actuator assembly includes a first arm pivotally coupled to a second arm. 
     
     
       26. The instrument of  claim 25 , wherein:
 said first arm includes a joint between a proximal end and a distal end of said first arm, said joint defining a proximal portion and a distal portion of said first arm; 
 said second arm includes a joint between a proximal end and a distal end of said second arm, said joint defining a proximal portion and a distal portion of said second arm; and 
 said proximal portion of said first arm and said proximal portion of said second arm are each pivotal about a respective one of said joints to orient said proximal portions transversely to said distal portions. 
 
     
     
       27. The instrument of  claim 25 , wherein said first arm and said second arm are spring biased away from one another. 
     
     
       28. The instrument of  claim 18 , wherein said actuator assembly includes a locking mechanism to hold said reducing member in a reduced position. 
     
     
       29. The instrument of  claim 18 , wherein said fastener engaging member includes a pair of flex arms extending proximally from said distal end thereof. 
     
     
       30. The instrument of  claim 29 , wherein each of said flex arms includes a prong at a distal end thereof, each of said prongs defining a channel for receiving the rod therein. 
     
     
       31. The instrument of  claim 30 , wherein said fastener engaging member includes a pair of elongated slots extending between said flex arms to said distal end. 
     
     
       32. A surgical instrument for reducing a rod toward a bone fastener, comprising:
 a fastener engaging member extending between a proximal end and a distal end, a distal portion of said fastener engaging member being adapted to engage the bone fastener; 
 a reducing member disposed about said fastener engaging member, said reducing member having a longitudinal axis oriented in its direction of movement; 
 an actuator assembly coupled between said fastener engaging member and said reducing member and operable to move said reducing member about said fastener engaging member between a reduced position and a retracted position, wherein said actuator assembly includes:
 a first link having a distal end pivotally coupled to a first side of said reducing member; 
 a first pivot arm having a distal end pivotally coupled to a proximal end of said first link, said first pivot arm having a medially extending connector pivotally coupled to said fastener engaging member; 
 a first arm having a distal end pivotally coupled to a proximal end of said first pivot arm, said first arm having a medially extending connector; 
 a second link having a distal end pivotally coupled to a second side of said reducing member opposite said first side; 
 a second pivot arm having a distal end pivotally coupled to a proximal end of said second link, said second pivot arm having a medially extending connector pivotally coupled to said medially extending connector of said first pivot arm and also pivotally coupled to said fastener engaging member; and 
 a second arm having a medially extending connector pivotally coupled to said medially extending connector of said first arm, said second arm having a distal end pivotally coupled to a proximal end of said second pivot arm, 
 
 wherein proximal ends of said first and second arm are biased together along a plane offset from the longitudinal axis to move said reducing member distally relative to said fastener engaging member to move the rod toward the bone fastener. 
 
     
     
       33. The instrument of  claim 32 , wherein:
 said first arm includes a joint between a proximal end and a distal end of said first arm, said joint defining a proximal portion and a distal portion of said first arm; 
 said second arm includes a joint between a proximal end and a distal end of said second arm, said joint defining a proximal portion and a distal portion of said second arm; and 
 said proximal portion of said first arm and said proximal portion of said second arm are each pivotal about a respective one of said joints to orient said proximal portions transversely to said distal portions. 
 
     
     
       34. The instrument of  claim 32 , wherein said first arm and said second arm are spring biased away from one another. 
     
     
       35. The instrument of  claim 32 , wherein said actuator assembly includes a locking mechanism at the proximal ends of said first and second arms to hold said reducing member in a reduced position. 
     
     
       36. The instrument of  claim 32 , wherein said first pivot arm and said second pivot arm each include a lateral offset to locate a proximal portion of the actuator assembly away from a proximal end opening of said fastener engaging member. 
     
     
       37. A surgical instrument for reducing a rod toward a bone fastener, comprising:
 a fastener engaging member extending between a proximal end and a distal end, a distal portion of said fastener engaging member being adapted to engage the bone fastener; 
 a reducing member disposed about said fastener engaging member, said reducing member having a longitudinal axis oriented in its direction of movement; 
 an actuator assembly coupled between said fastener engaging member and said reducing member and operable to move said reducing member about said fastener engaging member between a reduced position and a retracted position, wherein said actuator assembly includes:
 a first link having a distal end pivotally coupled to said reducing member; 
 a first arm having a distal end pivotally coupled to said fastener engaging member, said first arm extending to a proximal end, said first arm further being pivotally coupled between said proximal and distal ends to a proximal end of said first link; 
 a second link having a distal end pivotally coupled to said reducing member opposite said first link; and 
 a second arm having a distal end pivotally coupled to said fastener engaging member opposite said first arm, said second arm extending to a proximal end, said second arm further being pivotally coupled between said proximal and distal ends to a proximal end of said second link, 
 
 wherein proximal ends of said first and second arm are biased together along a plane offset from the longitudinal axis to move said reducing member distally relative to said fastener engaging member to move the rod toward the bone fastener. 
 
     
     
       38. The instrument of  claim 37 , wherein said actuator assembly, said reducing member, and said fastener engaging member have a common central axis. 
     
     
       39. The instrument of  claim 37 , wherein said first arm and said second arm each include a laterally extending blocking arm for contacting a proximal end of an access tube and limiting the insertion depth of the surgical instrument therein. 
     
     
       40. A surgical instrument for reducing a rod toward a bone fastener, comprising:
 a fastener engaging member extending between a proximal end and a distal end, a distal portion of said fastener engaging member being adapted to receive a portion of the rod therein and being further adapted to engage the bone fastener; 
 a reducing member having (1) a longitudinal axis oriented in a direction of movement of said reducing member, and (2) a body movably disposed about said fastener engaging member, said body having an extension portion extending proximally from a distal end of said reducing member; and 
 an actuator assembly, comprising a first arm and a second arm, operable to move said reducing member distally with respect to said fastener engaging member when proximal ends of said first and second arms are biased together, whereby, with biasing together of said first and second arms, said distal end of said reducing member contacts the rod to move the rod distally, relative to said fastener engaging member, toward the bone fastener, wherein said reducing member can be moved distally so that said extension portion is positioned distally of said distal end of said fastener engaging member, 
 wherein a plane along which said first and second arms move is offset from the longitudinal axis. 
 
     
     
       41. The instrument of  claim 40 , wherein said reducing member defines a passage extending between a proximal end and a distal end thereof. 
     
     
       42. The instrument of  claim 41 , wherein said passage has a distal portion defined by said extension portion and proximal portion extending from said distal portion to said proximal end of said reducing member, said reducing member defining a lip between said proximal and distal portions of said passage. 
     
     
       43. The instrument of  claim 42 , wherein said fastener engaging member has an enlarged rim about its distal end, said rim contacting said lip to establish a predetermined reduction distance for said extension portion with respect to said fastener engaging member. 
     
     
       44. A method of reducing an elongated implant member in orthopedic surgery, comprising:
 fixing a fastener to a patient; 
 placing an elongated implant member adjacent said fastener; 
 providing a rod reducer instrument having a first arm and a second arm; 
 inserting said rod reducer instrument through an access tube providing access to said fastener and said elongated implant member; 
 placing a distal portion of a fastener engaging member of said rod reducer instrument over said elongated implant member; 
 engaging said distal portion of said fastener engaging member to said fastener; and 
 moving a reducing member distally about the fastener engaging member so that said reducing member contacts said elongated implant member and forces said elongated implant member toward said fastener, said moving step comprising biasing together proximal ends of said first and second arms to move the reducing member distally to force said elongated implant member toward said fastener, 
 wherein said reducing member has a longitudinal axis oriented in a reducing direction and said first and second arms are biased together along a plane offset from the longitudinal axis to move said reducing member. 
 
     
     
       45. The method of  claim 44 , further comprising:
 moving said reducing member to position said elongated implant member at a first location in the yoke of the fastener; and 
 engaging said elongated implant member in said yoke with a set screw inserted through a passage defined by said fastener engaging member. 
 
     
     
       46. A method of reducing an elongated implant member in orthopedic surgery, comprising:
 fixing first and second fasteners to a patient; 
 placing an elongated implant member adjacent said first and second fasteners; 
 providing a rod reducer instrument having a first arm and a second arm; 
 placing a distal portion of a fastener engaging member of said rod reducer instrument over said elongated implant member; 
 engaging said distal portion of said fastener engaging member of said rod reducer instrument to said fastener; 
 moving a reducing member of said rod reducer instrument distally with respect to said fastener engaging member so that said rod reducer instrument contacts said elongated implant member and forces said elongated implant member a first distance toward said first fastener; 
 securing said elongated implant member to said first fastener; 
 modifying said rod reducer instrument; 
 placing the distal portion of the fastener engaging member of the modified rod reducer instrument over said elongated implant member; 
 engaging said distal portion of said fastener engaging member of said modified rod reducer instrument to said second fastener; 
 moving said reducing member of said modified rod reducer instrument distally with respect to said fastener engaging member so that said modified rod reducer instrument contacts said elongated implant member and forces said elongated implant member a second distance toward said second fastener, said second distance being different than said first distance; and 
 securing said elongated implant member to the second fastener, 
 wherein said reducing member has a longitudinal axis oriented in a reducing direction and, to move said reducing member distally to force said elongated implant member toward a fastener, said first and second arms are biased together so as to move along a plane offset from the longitudinal axis. 
 
     
     
       47. The method of  claim 46 , wherein securing said elongated implant member includes engaging said elongated implant member in a yoke of said first and second fasteners with a set screw inserted through a passage defined by said fastener engaging member of each of said rod reducer instrument and said modified rod reducer instrument. 
     
     
       48. The instrument of claim 1, wherein said surgical instrument includes a viewing area for visualization of the rod and bone fastener when said reducing member brings the rod into contact with the bone fastener. 
     
     
       49. The instrument of claim 18, wherein said surgical instrument includes a viewing area for visualization of the rod and bone fastener when said reducing member brings the rod into contact with the bone fastener. 
     
     
       50. The instrument of claim 1, wherein said first and second arms are actuated about a common pivot axis located between proximal and distal ends of said first and second arms. 
     
     
       51. The instrument of claim 1, wherein a longitudinal axis of said reducing member intersects a pivot axis about which said first and second arms pivot. 
     
     
       52. The instrument of claim 1, wherein said fastener engaging member defines a passage, along a longitudinal axis, having first and second openings aligned with the longitudinal axis, with said first opening of said passage being at said distal portion of said fastener engaging member, and
 wherein said first and second arms are pivotally coupled to each other at a position along said instrument spaced proximally from said second opening.   
     
     
       53. The instrument of claim 1, wherein said first arm is pivotally coupled to said second arm,
 said fastener engaging member and said reducing member are reciprocally slidably coupled,   said first and second arms are actuated about a common pivot axis located between proximal and distal ends of said first and second arms, and   said reducing member moves the rod in a longitudinally oriented direction with respect to the bone fastener.   
     
     
       54. The instrument of claim 53, wherein said fastener engaging member includes a pair of flex arms extending proximally from said distal end thereof, and wherein said reducing member and said fastener engaging member each include a generally circular cross-section. 
     
     
       55. The instrument of claim 18, wherein said first and second arms are actuated about a common pivot axis located between proximal and distal ends of said first and second arms. 
     
     
       56. The instrument of claim 18, wherein a longitudinal axis of said reducing member intersects a pivot axis about which said first and second arms pivot. 
     
     
       57. The instrument of claim 18, wherein said passage extends along a longitudinal axis of said fastener engaging member, between said proximal end opening and a distal end opening, said openings aligned with the longitudinal axis, and
 wherein said first and second arms are pivotally coupled to each other at a position along said instrument spaced proximally from said proximal end opening.   
     
     
       58. The instrument of claim 18, wherein said first arm is pivotally coupled to said second arm,
 said fastener engaging member and said reducing member are reciprocally slidably coupled,   said first and second arms are actuated about a common pivot axis located between proximal and distal ends of said first and second arms, and   said reducing member moves the rod in a longitudinally oriented direction with respect to the bone fastener.   
     
     
       59. The instrument of claim 58, wherein said fastener engaging member includes a pair of flex arms extending proximally from said distal end thereof, and wherein said reducing member and said fastener engaging member each include a generally circular cross-section. 
     
     
       60. The instrument of claim 39, wherein said surgical instrument includes a viewing area for visualization of the rod and bone fastener when said reducing member brings the rod into contact with the bone fastener. 
     
     
       61. The method of claim 44, further comprising viewing said elongated implant member and said fastener during said moving step when said elongated implant member and said fastener are brought into contact. 
     
     
       62. The method of claim 44, wherein said sub-step moves the rod in a longitudinally oriented direction with respect to said fastener. 
     
     
       63. The method of claim 62, wherein said first and second arms are actuated about a common pivot axis located between proximal and distal ends of said first and second arms. 
     
     
       64. The method of claim 44, wherein a longitudinal axis of a reducing member of said rod reducer instrument intersects a pivot axis about which said first and second arms pivot. 
     
     
       65. The method of claim 44, wherein said fastener engaging member defines a passage, along a longitudinal axis, having first and second openings aligned with the longitudinal axis, with said first opening of said passage being at said distal portion of said fastener engaging member, and
 wherein said first and second arms are pivotally coupled to each other at a position along said instrument spaced proximally from said second opening.