Percutaneous access devices and bone anchor assemblies

Abstract

A percutaneous access device includes an inner tube and an outer tube disposed about at least a portion of the inner tube. The outer tube may be sized to span from a skin incision in a patient to a site proximate the spine of the patient. The distal end of the outer tube may be adapted to releasably engage a bone anchor. The inner tube may be adjustable relative to the outer tube between a first position and a second position in which the distal end of the inner tube contacts the bone anchor. A bone anchor assembly includes a bone anchor having a distal bone engaging portion and a receiving member having a recess for receiving a spinal fixation element. The proximal end of the receiving member may have an arcuate groove formed on an exterior surface thereof to facilitate connection of an instrument to the receiving member.

1 - 46 . (canceled) 
     
     
         47 . A system for anchoring an elongated implant to a vertebra of a patient spine, the system comprising:
 an elongated guide tool comprising an anchor coupling region comprising a first leg spaced apart from a second leg, the first leg comprising an attachment structure projecting radially inward; and   a bone anchor comprising:
 an anchoring member configured to be received in the vertebra in an anchoring manner, the anchoring member comprising a distal portion and a proximal portion opposite the distal portion, the distal portion configured to lead the anchoring member into the vertebra when the anchoring member is being anchored in the vertebra; and 
 a head coupled to the proximal portion of the anchoring member and configured to couple to the elongated implant, the head comprising:
 an outer surface facing radially outward relative to a longitudinal center axis of the head; and 
 a slot extending along at least a portion of the outer surface in a direction perpendicular to the longitudinal center axis of the head, the head configured to be received between the first and second legs when the bone anchor is coupled to the elongated guide tool, and the slot configured to receive the attachment structure when the bone anchor is coupled to the elongated guide tool. 
 
   
     
     
         48 . The system of  claim 47 , wherein the elongated guide tool further comprises a tubular body comprising a tubular wall defining an interior channel extending longitudinally through the tubular body, the tubular wall comprising a first opening and a second opening both of which extend longitudinally along the tubular body from a distal end of the tubular body towards a proximal end of the tubular body, both of the first opening and second opening radially extending through the tubular wall to open into the interior channel, the first opening being opposite the second opening and comprising a greater longitudinal length than the second opening. 
     
     
         49 . The system of  claim 48 , wherein the head in being configured to couple to the elongated implant comprises a channel that distally extends from a proximal end of the head along the longitudinal center axis of the head, and
 wherein, when the head is received between the first and second legs and the attachment structure is received in the slot, the first opening and the second opening align with the channel of the head to form a combined channel extending from the channel of the head and along the tubular body via the first opening and the second opening.   
     
     
         50 . The system of  claim 49 , further comprising:
 a closure top configured to be threaded into a proximal region of the channel of the head, the closure top further configured to be routed along the interior channel of the tubular body; and   a closure installation tool comprising a distal end configured to engage the closure top to thread the closure top into the proximal region of the channel of the head, the closure installation tool further configured to extend along the interior channel of the tubular body.   
     
     
         51 . The system of  claim 48 , further comprising a pusher tool comprising a distal end that engages the elongated implant and displaces along the tubular body in displacing the elongated implant along at least one of the first opening or the second opening. 
     
     
         52 . The system of  claim 51 , wherein the pusher tool is configured for displacement through the interior channel of the tubular body as the pusher tool is used to displace the elongated implant along the at least one of the first opening or the second opening. 
     
     
         53 . The system of  claim 48 , wherein the first opening is wider near where it intersects the distal end of the tubular body than more proximal along the tubular body. 
     
     
         54 . The system of  claim 53 , wherein the first opening being wider near where it intersects the distal end of the tubular body facilitates the decoupling of the attachment structure from the slot via rotation of the tubular body relative to the head about a longitudinal axis of the tubular body. 
     
     
         55 . The system of  claim 47 , wherein the slot is configured such that the slot receives the attachment structure in a snap-on relationship. 
     
     
         56 . The system of  claim 47 , wherein the slot is configured such that splaying is inhibited between the first leg and the second leg when the slot receives the attachment structure. 
     
     
         57 . The system of  claim 47 , wherein the slot comprises a recessed overhanging configuration at a proximal boundary of the slot. 
     
     
         58 . The system of  claim 57 , wherein the recessed overhanging configuration at the proximal boundary of the slot interacts with the attachment structure to inhibit the first leg and the second leg from splaying apart when the bone anchor is coupled to the elongated guide tool. 
     
     
         59 . The system of  claim 47 , wherein the slot comprises a proximal boundary comprising a radially inner extent and a radially outer extent radially outward of the radially inner extent, wherein the radially outer extent is distal the radially inner extent. 
     
     
         60 . The system of  claim 59 , wherein, when the bone anchor is coupled to the elongated guide tool, a free end of the attachment structure is received in a proximal recess defined by the radially inner extent and the radially outer extent. 
     
     
         61 . The system of  claim 60 , wherein the free end and the radially outer extent interact to inhibit the attachment structure from radially outward displacement. 
     
     
         62 . The system of  claim 47 , wherein the slot comprises a proximal boundary comprising a distal projecting lip structure and, when the bone anchor is coupled to the elongated guide tool, the attachment structure engages the distal projecting lip. 
     
     
         63 . The system of  claim 62 , wherein the attachment structure engaging the distal projecting lip acts to inhibit the attachment structure from radially outward displacement. 
     
     
         64 . The system of  claim 47 , wherein the outer surface comprises a cylindrical nature, and the slot extends circumferentially along at least a portion of the outer surface. 
     
     
         65 . The system of  claim 47 , wherein the head further comprises a proximal end and a distal end opposite the proximal end, the distal end receiving the proximal portion in the head being coupled to the proximal portion, the proximal end comprising a surface perpendicular to the outer surface. 
     
     
         66 . The system of  claim 65 , wherein the surface of the proximal end is planar. 
     
     
         67 . The system of  claim 65 , wherein the head further comprises a first arm and a second arm spaced apart from the first arm to define a channel in which the elongated implant is received to couple the head to the elongated implant, and the surface of the proximal end is on a proximal end of at least the first arm or the second arm. 
     
     
         68 . The system of  claim 65 , wherein the slot is greatly closer in proximity to the proximal end than the distal end. 
     
     
         69 . The system of  claim 68 , wherein the slot intersects the channel. 
     
     
         70 . The system of  claim 47 , wherein the anchoring member at least one of comprises a threaded shank or is a threaded shank. 
     
     
         71 . The system of  claim 47 , wherein the bone anchor is a bone screw. 
     
     
         72 . The system of  claim 71 , wherein the bone screw is a polyaxial bone screw. 
     
     
         73 . The system of  claim 47 , wherein the distal portion comprises a tapered tip. 
     
     
         74 . The system of  claim 73 , wherein the tapered tip is part of a threaded shank of a bone screw. 
     
     
         75 . The system of  claim 47 , wherein the head is moveably coupled to the proximal portion of the anchoring member. 
     
     
         76 . The system of  claim 47 , wherein the head further comprises a first arm and a second arm spaced apart from the first arm to define a channel in which the elongated implant is received to couple the head to the elongated implant. 
     
     
         77 . The system of  claim 76 , wherein the slot intersects the channel. 
     
     
         78 . The system of  claim 76 , wherein the elongated implant comprises an implantable rod. 
     
     
         79 . The system of  claim 76 , wherein the outer surface is defined on the first arm. 
     
     
         80 . The system of  claim 76 , wherein the first arm and second arm each comprise radially inward projecting threads adjacent the channel and are both configured to receive a threaded closure top configured to retain the elongated implant in the channel. 
     
     
         81 . The system of  claim 47 , wherein the anchoring member is longitudinally cannulated. 
     
     
         82 . The system of  claim 47 , wherein the slot is configured to facilitate the attachment structure decoupling from the slot via rotation of the elongated guide tool relative to the head of the bone anchor. 
     
     
         83 . The system of  claim 82 , wherein the rotation is about the longitudinal center axis of the head. 
     
     
         84 . The system of  claim 47 , wherein the slot comprises a planar boundary perpendicular to the longitudinal center axis of the head and perpendicularly intersecting the outer surface. 
     
     
         85 . A system for anchoring an elongated implant to a vertebra of a patient spine, the system comprising:
 a tool comprising an anchor coupling region comprising an attachment structure projecting radially inward; and   a bone anchor comprising:
 an anchoring member comprising a distal portion and a proximal portion opposite the distal portion, the distal portion configured to reside in the vertebra when the anchoring member is anchored in the vertebra; and 
 a head coupled to the proximal portion of the anchoring member and configured to couple to the elongated implant, the head comprising:
 an outer surface facing radially outward relative to a longitudinal center axis of the head; 
 a slot extending along at least a portion of the outer surface in a direction perpendicular to the longitudinal center axis of the head, the slot configured to receive the attachment structure when the bone anchor is coupled to the tool; 
 a threaded inner surface facing radially inward towards the longitudinal center axis of the head, the threaded inner surface configured to threadably engage with a threaded outer surface of a threaded closure top; and 
 a channel extending distally along the longitudinal center axis of the head from a proximal end of the head and configured to receive the elongated implant. 
 
   
     
     
         86 . The system of  claim 85 , wherein the tool and the head are configured such that the threaded outer surface can threadably engage the threaded inner surface when the bone anchor is coupled to the tool with the attachment structure received in the slot. 
     
     
         87 . The system of  claim 85 , wherein the tool and the slot are configured such that the slot receives the attachment structure in a snap-on relationship. 
     
     
         88 . The system of  claim 85 , wherein the tool further comprises a first leg and a second leg offset from the first leg, the attachment structure projecting radially inward from the first leg, the slot being configured such that splaying is inhibited between the first leg and the second leg when the slot receives the attachment structure. 
     
     
         89 . The system of  claim 85 , wherein the slot comprises a recessed overhanging configuration at a proximal boundary of the slot. 
     
     
         90 . The system of  claim 89 , wherein the recessed overhanging configuration at the proximal boundary of the slot interacts with the attachment structure to inhibit radially outward displacement of the attachment structure when the attachment structure is received in the slot. 
     
     
         91 . The system of  claim 85 , wherein the slot comprises a proximal boundary comprising a radially inner extent and a radially outer extent radially outward of the radially inner extent, wherein the radially outer extent is distal the radially inner extent. 
     
     
         92 . The system of  claim 91 , wherein, when the bone anchor is coupled to the tool, a free end of the attachment structure is received in a proximal recess defined by the radially inner extent and the radially outer extent. 
     
     
         93 . The system of  claim 92 , wherein the free end and the radially outer extent interact to inhibit the attachment structure from radially outward displacement. 
     
     
         94 . The system of  claim 85 , wherein the slot comprises a proximal boundary comprising a distal projecting lip structure and, when the bone anchor is coupled to the tool, the attachment structure engages the distal projecting lip. 
     
     
         95 . The system of  claim 94 , wherein the attachment structure engaging the distal projecting lip acts to inhibit the attachment structure from radially outward displacement. 
     
     
         96 . The system of  claim 85 , wherein the outer surface comprises a cylindrical nature, and the slot extends circumferentially along at least a portion of the outer surface. 
     
     
         97 . The system of  claim 85 , wherein the head further comprises a proximal end and a distal end opposite the proximal end, the distal end receiving the proximal portion in the head being coupled to the proximal portion, the proximal end comprising a surface perpendicular to the outer surface. 
     
     
         98 . The system of  claim 97 , wherein the surface of the proximal end is planar. 
     
     
         99 . The system of  claim 97 , wherein the head further comprises a first arm and a second arm spaced apart from the first arm to define the channel in which the elongated implant is received to couple the head to the elongated implant, and the surface of the proximal end is on a proximal end of at least the first arm or the second arm. 
     
     
         100 . The system of  claim 97 , wherein the slot is greatly closer in proximity to the proximal end than the distal end. 
     
     
         101 . The system of  claim 100 , wherein the slot intersects the channel. 
     
     
         102 . The system of  claim 85 , wherein the anchoring member comprises a threaded shank. 
     
     
         103 . The system of  claim 85 , wherein the bone anchor is a bone screw. 
     
     
         104 . The system of  claim 103 , wherein the bone screw is a polyaxial bone screw. 
     
     
         105 . The system of  claim 85 , wherein the distal portion comprises a tapered tip. 
     
     
         106 . The system of  claim 105 , wherein the tapered tip is part of a threaded shank of a bone screw. 
     
     
         107 . The system of  claim 85 , wherein the head is moveably coupled to the proximal portion of the anchoring member. 
     
     
         108 . The system of  claim 85 , wherein the head further comprises a first arm and a second arm spaced apart from the first arm to define the channel in which the elongated implant is received to couple the head to the elongated implant. 
     
     
         109 . The system of  claim 108 , wherein the slot intersects the channel. 
     
     
         110 . The system of  claim 108 , wherein the elongated implant comprises an implantable rod. 
     
     
         111 . The system of  claim 108 , wherein the outer surface is defined on the first arm. 
     
     
         112 . The system of  claim 108 , wherein the threaded inner surface is defined on at least one of the first arm and the second arm. 
     
     
         113 . The system of  claim 85 , wherein the anchoring member is longitudinally cannulated.