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 adapted to engage the bone fastener; 
 a reducing member positioned along and movable relative to 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 the 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 reducing member is positioned about said fastener engaging member. 
     
     
       3. The instrument of  claim 1 , wherein said actuator assembly is adapted to receive a portion of the rod therein. 
     
     
       4. 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. 
     
     
       5. The instrument of  claim 1 , wherein said actuator assembly includes a first arm is pivotally coupled to a said second arm. 
     
     
       6. The instrument of  claim 5 , 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. 
 
     
     
       7. The instrument of  claim 1 , wherein said actuator assembly includes a locking mechanism to hold said reducing member in a reduced position. 
     
     
       8. The instrument of  claim 1 , wherein said actuator assembly is spring biased to a reducing member retracted position. 
     
     
       9. The instrument of  claim 1 , wherein said fastener engaging member includes a pair of flex arms extending proximally from said distal end thereof. 
     
     
       10. The instrument of  claim 9 , 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. 
     
     
       11. The instrument of  claim 10 , wherein said reducing member is positionable over at least a portion of said prongs. 
     
     
       12. The instrument of  claim 9 , wherein said fastener engaging member includes a pair of elongated slots extending between said flex arms opening at said distal end. 
     
     
       13. The instrument of  claim 12 , 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. 
     
     
       14. The instrument of  claim 1 , wherein said fastener engaging member and said reducing member are reciprocally slidably coupled. 
     
     
       15. The instrument of  claim 1 , wherein said reducing member and said fastener engaging member each include a generally circular cross-section. 
     
     
       16. 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. 
 
     
     
       17. 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. 
 
     
     
       18. 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. 
 
     
     
       19. The instrument of  claim 18 , further comprising a stop member at said proximal end of said fastener engaging member to limit proximal movement of said reducing member. 
     
     
       20. 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 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 (i) at least a portion of said actuator assembly being is offset laterally with respect to said fastener engaging member to locate said proximal portion of said actuator assembly away from a proximal end opening of said passage of said fastener engaging member, wherein (ii) said actuator assembly is operable to move said reducing member distally, relative to said fastener engaging member, to contact the rod to move the rod and bone fastener toward one another, (iii) proximal ends of said first and second arms are biased together to move the rod distally toward the bone fastener, and (iv) a plane along which said first and second arms move is offset from the longitudinal axis. 
 
     
     
       21. The instrument of  claim 20 , wherein said actuator assembly is operable to move said reducing member distally with respect to said fastener engaging member. 
     
     
       22. The instrument of  claim 20 , wherein said actuator assembly includes a lateral offset portion to laterally offset said proximal portion of said actuator assembly is offset away from a proximal end opening of said passage of said fastener engaging member. 
     
     
       23. The instrument of  claim 20 , wherein said reducing member is positioned about said fastener engaging member and slidable with respect thereto in response to operation of said actuator assembly. 
     
     
       24. The instrument of  claim 23 , wherein said distal end of said fastener engaging member includes a pair of prongs forming a rod passage. 
     
     
       25. The instrument of  claim 24 , 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. 
     
     
       26. The instrument of  claim 20 , 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. 
 
     
     
       27. The instrument of  claim 20 , wherein said actuator assembly includes a first arm is pivotally coupled to a said second arm. 
     
     
       28. The instrument of  claim 27 , 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. 
 
     
     
       29. The instrument of  claim 27  wherein said first arm and said second arm are spring biased away from one another. 
     
     
       30. The instrument of  claim 20 , wherein said actuator assembly includes a locking mechanism to hold said reducing member in a reduced position. 
     
     
       31. The instrument of  claim 20 , wherein said fastener engaging member includes a pair of flex arms extending proximally from said distal end thereof. 
     
     
       32. The instrument of  claim 20 , 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. 
     
     
       33. The instrument of  claim 32 , wherein said fastener engaging member includes a pair of elongated slots extending between said flex arms to said distal end. 
     
     
       34. A method of positioning an elongated implant member in a patient, comprising:
 fixing a fastener to a patient; 
 placing an elongated implant member adjacent said fastener; 
 providing a rod reducer instrument; 
 inserting said rod reducer instrument through an access tube providing access to said fastener and said elongated implant member; 
 engaging a distal portion of a fastener engaging member of said rod reducer instrument to said fastener; and 
 moving a reducing member of said rod reducer instrument distally so that said reducing member contacts said elongated implant member and moves said elongated implant member toward said fastener, said moving step comprising biasing together proximal ends of first and second arms of an actuator to move said reducing member distally to move said elongated implant member toward said fastener, 
 wherein the reducing member has a longitudinal axis oriented in a reducing direction and the first and second arms move along a plane offset from the longitudinal axis to move said reducing member. 
 
     
     
       35. The method of  claim 34 ; further comprising:
 positioning said elongated implant member adjacent said fastener with said reducing member; and 
 engaging said elongated implant member to said fastener through said access tube. 
 
     
     
       36. The method of  claim 34 , further comprising moving said reducing member about said fastener engaging member to contact said elongated implant member. 
     
     
       37. The method of  claim 34 , further comprising:
 fixing a second fastener to a patient; 
 modifying said reducing member of said rod reducer instrument; 
 engaging the distal portion of the fastener engaging member of the modified rod reducer instrument to said second fastener; and 
 moving said modified reducing member distally with respect to said fastener engaging member so that said modified rod reducer member contacts said elongated implant member and moves said elongated implant member toward said second fastener. 
 
     
     
       38. The method of  claim 34 , further comprising placing said fastener engaging member about said elongated implant member. 
     
     
       39. The method of  claim 34 , further comprising:
 positioning said elongated implant member adjacent said fastener with said reducing member; 
 placing a fastener through a passage defined by said fastener engaging member; and 
 securing said elongated implant member to said fastener through said access tube. 
 
     
     
       40. A method of securing an elongated implant member to a fastener, comprising:
 coupling a rod reducer instrument to the fastener, said rod reducer instrument having a passage extending therethrough, along a longitudinal axis, in communication with said fastener; 
 moving a reducing member of said rod reducer instrument distally so that said reducing member contacts said elongated implant member and positions said elongated implant member adjacent said fastener, said moving step comprising biasing proximal ends of first and second arms of an actuator together to move said reducing member distally to position said elongated implant member adjacent said fastener; and 
 securing said elongated implant member to said fastener through said passage, 
 wherein the first and second arms move along a plane offset from the longitudinal axis to move said reducing member. 
 
     
     
       41. The method of  claim 40 , wherein said rod reducer instrument includes a fastener engaging member engagable to said fastener and defining said passage therethrough. 
     
     
       42. The method of  claim 41 , wherein said reducing member is positioned about said fastener engaging member. 
     
     
       43. The method of  claim 40 , further comprising inserting the rod reducer instrument through an access tube to the fastener. 
     
     
       44. 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. 
     
     
       45. The instrument of claim 20, 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. 
     
     
       46. The method of claim 34, further comprising viewing said elongated implant member and fastener during said moving step when said elongated implant member and fastener are brought into contact. 
     
     
       47. The method of claim 40, further comprising viewing said elongated implant member and said fastener during said moving step when said elongated implant member and fastener are moved adjacent each other. 
     
     
       48. 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. 
     
     
       49. The instrument of claim 1, wherein the longitudinal axis intersects a pivot axis about which said first and second arms pivot. 
     
     
       50. The instrument of claim 2, wherein the longitudinal axis intersects a pivot axis about which said first and second arms pivot. 
     
     
       51. The instrument of claim 1, wherein said fastener engaging member defines a passage, along the 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.   
     
     
       52. 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.   
     
     
       53. The instrument of claim 52, wherein said fastener engaging member includes a pair of flex arms extending proximally from said distal end thereof, and said reducing member and said fastener engaging member each include a generally circular cross-section. 
     
     
       54. The instrument of claim 20, wherein the longitudinal axis intersects a pivot axis about which said first and second arms pivot. 
     
     
       55. The instrument of claim 20, wherein said passage extends along the longitudinal axis between said proximal end opening and a distal end opening, said openings being 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.   
     
     
       56. The method of claim 40, wherein an engaging member for performing the coupling in said coupling step includes a pair of elongated slots extending between a pair of flex arms, which open at a distal end thereof. 
     
     
       57. The method of claim 40, wherein said sub-step moves said elongated implant member in a longitudinal direction with respect to said rod reducer instrument. 
     
     
       58. The method of claim 40, wherein said sub-step moves said elongated member in a longitudinally oriented direction with respect to said fastener. 
     
     
       59. The method of claim 58, 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. 
     
     
       60. The instrument of claim 40, wherein the longitudinal axis of said reducing member intersects a pivot axis about which said first and second arms pivot. 
     
     
       61. The method of claim 40, wherein said passage has first and second openings aligned with the longitudinal axis, with said first opening of said passage being at a distal portion of said rod reducer instrument, and
 wherein said first and second arms are pivotally coupled to each other at a position along said rod reducer instrument spaced proximally from said second opening.   
     
     
       62. The instrument of claim 1, wherein the plane and the longitudinal axis are offset by less than 30 mm. 
     
     
       63. The instrument of claim 1, wherein the plane and the longitudinal axis do not intersect. 
     
     
       64. 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 adapted to engage the bone fastener;   a reducing member positioned along and movable relative to said fastener engaging member, said reducing member having a distal end and a longitudinal axis oriented in the 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 free ends of said first and second arms are biased together, whereby said distal end of said reducing member contacts the rod to move the rod toward the bone fastener,   wherein said first and second arm further comprise respective distal ends and are interconnected at intermediate positions such that said distal ends move apart when the proximal free ends are biased together,   wherein said first and second handles extend laterally away from the longitudinal axis, and   wherein said fastener engaging member and said reducing member define an open passage to the rod, along the longitudinal axis, during actuation by said actuator assembly.   
     
     
       65. 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 adapted to engage the bone fastener;   a reducing member positioned along and movable relative to 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 the fastener engaging member, toward the bone fastener,   wherein said first and second arms are connected at an intermediate connection point such that the biasing together of proximal ends of said first and second arms moves apart the distal ends of said first and second arms.   
     
     
       66. The surgical instrument of claim 65, wherein said proximal ends of said first and second arms and said connection point of said actuator assembly are offset laterally from an extending direction of said fastener engaging member, to position said proximal ends of said first and second arms and said connection point away from a proximal end opening of a passage extending through said fastener engaging member. 
     
     
       67. The surgical instrument of claim 65, wherein the distal end of said fastener engaging member defines opposing arms that engage the bone fastener. 
     
     
       68. The surgical instrument of claim 67, wherein a side gap defined by said opposing arms of said fastener engaging member aligns with a side gap of the bone fastener that receives the rod. 
     
     
       69. The surgical instrument of claim 66, further comprising a biasing mechanism for biasing apart the proximal ends of said first and second arms. 
     
     
       70. The surgical instrument of claim 69, further comprising a locking system that secures said proximal ends of said first and second arms relative to each other to prevent said proximal ends from spreading apart in response to said biasing mechanism. 
     
     
       71. The surgical instrument of claim 70, wherein said locking system can secure said proximal ends of said first and second arms relative to each other at a plurality of positions, each position providing a different distance between said proximal ends of said first and second arms. 
     
     
       72. The surgical instrument of claim 69, wherein said biasing mechanism includes a leaf spring. 
     
     
       73. The surgical instrument of claim 65, wherein the distal end of at least one of said first and second arms includes a hole, and
 wherein said at least one of first and second arms pivots about said hole when a pin is provided in said hole.   
     
     
       74. The surgical instrument of claim 65, wherein said reducing member engages a surface of said fastener engaging member to limit an amount of play of said reducing member. 
     
     
       75. The surgical instrument of claim 65, wherein said reducing member includes a lip adapted to limit a longitudinal movement of said reducing member relative to said fastener engaging member. 
     
     
       76. The surgical instrument of claim 65, wherein said fastener engaging member includes a rim adapted to limit a longitudinal movement of said reducing member relative to said fastener engaging member. 
     
     
       77. The surgical instrument of claim 65, wherein said reducing member includes a substantially cylindrical body. 
     
     
       78. The surgical instrument of claim 65, wherein said reducing member includes a body having a circular cross-section. 
     
     
       79. The surgical instrument of claim 65, further comprising a third arm pivotally coupled to the distal end of one of said first and second arms,
 wherein the biasing together of said first and second arms pivots the distal end of the one of said first and second arms with respect to said third arm, to move the reducing member distally with respect to said fastener engaging member.   
     
     
       80. The surgical instrument of claim 66, further comprising a third arm, wherein a first portion of said third arm is pivotally coupled to the distal end of one of said first and second arms, and the biasing together of said first and second arms pivots the distal end of the one of said first and second arms with respect to said third arm, to move the reducing member distally with respect to said fastener engaging member.