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 bone anchor to anchor an elongated implant to a patient bone and threadably engage with a closure plug, the bone anchor further to couple with a tool comprising an attachment structure, the bone anchor comprising:
 an anchoring member comprising a distal portion and a proximal portion opposite the distal portion, the distal portion to attach to the patient bone in an anchoring manner; and   a head coupled to the proximal portion of the anchoring member, the head to couple to the elongated implant, the head comprising:
 a proximal end and a distal end opposite the proximal end, the proximal portion of the anchoring member extending into the distal end such that the head is coupled to the proximal portion of the anchoring member; 
 a first arm and a second arm spaced apart from the first arm to define a channel to receive the elongated implant to couple the head to the elongated implant, the channel extending distally from the proximal end; 
 a helically wound thread defined in an inner surface of the channel, the inner surface facing radially inward towards a longitudinal center axis of the head, the helically wound thread to threadably engage with the closure plug when the closure plug is received in the channel; 
 an outer surface facing radially outward relative to the longitudinal center axis of the head, the outer surface being on the first arm; and 
 a horizontal radiused slot near the proximal end of the head and extending along at least a portion of the outer surface in a direction perpendicular to the longitudinal center axis of the head, the slot to receive the attachment structure when the bone anchor is coupled to the tool; and 
   wherein the horizontal radiused 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.   
     
     
         48 . The bone anchor of  claim 47 , 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. 
     
     
         49 . The bone anchor of  claim 48 , wherein the free end and the radially outer extent interact to inhibit the attachment structure from radially outward displacement. 
     
     
         50 . A bone anchor to anchor an elongated implant to a patient bone and threadably engage with a closure plug, the bone anchor further to couple with a tool comprising an attachment structure, the bone anchor comprising:
 an anchoring member comprising a distal portion and a proximal portion opposite the distal portion, the distal portion to attach to the patient bone in an anchoring manner; and   a head coupled to the proximal portion of the anchoring member, the head to couple to the elongated implant, the head comprising:
 a proximal end and a distal end opposite the proximal end, the proximal portion of the anchoring member extending into the distal end such that the head is coupled to the proximal portion of the anchoring member; 
 a first arm and a second arm spaced apart from the first arm to define a channel to receive the elongated implant to couple the head to the elongated implant, the channel extending distally from the proximal end; 
 a helically wound thread defined in an inner surface of the channel, the inner surface facing radially inward towards a longitudinal center axis of the head, the helically wound thread to threadably engage with the closure plug when the closure plug is received in the channel; 
 an outer surface facing radially outward relative to the longitudinal center axis of the head, the outer surface being on the first arm; and 
 a horizontal radiused slot near the proximal end of the head and extending along at least a portion of the outer surface in a direction perpendicular to the longitudinal center axis of the head, the slot to receive the attachment structure when the bone anchor is coupled to the tool; and 
   wherein the horizontal radiused 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.   
     
     
         51 . The bone anchor of  claim 50 , wherein the attachment structure engaging the distal projecting lip acts to inhibit the attachment structure from radially outward displacement. 
     
     
         52 . A bone anchor to anchor an elongated implant to a patient bone and threadably engage with a closure plug, the bone anchor further to couple with a tool comprising an attachment structure, the bone anchor comprising:
 an anchoring member comprising a distal portion and a proximal portion opposite the distal portion, the distal portion to attach to the patient bone in an anchoring manner; and   a head coupled to the proximal portion of the anchoring member, the head to couple to the elongated implant, the head comprising:
 a proximal end and a distal end opposite the proximal end, the proximal portion of the anchoring member extending into the distal end such that the head is coupled to the proximal portion of the anchoring member; 
 a first arm and a second arm spaced apart from the first arm to define a channel to receive the elongated implant to couple the head to the elongated implant, the channel extending distally from the proximal end; 
 a helically wound thread defined in an inner surface of the channel, the inner surface facing radially inward towards a longitudinal center axis of the head, the helically wound thread to threadably engage with the closure plug when the closure plug is received in the channel; 
 an outer surface facing radially outward relative to the longitudinal center axis of the head, the outer surface being on the first arm; and 
 a horizontal radiused slot near the proximal end of the head and extending along at least a portion of the outer surface in a direction perpendicular to the longitudinal center axis of the head, the slot to receive the attachment structure when the bone anchor is coupled to the tool; 
   wherein the slot comprises a boundary that comprises a structural configuration that interacts with the attachment structure to inhibit radially outward displacement of the attachment structure from the slot in which the attachment structure is received; and   wherein the structural configuration comprises a lip structure.   
     
     
         53 . The bone anchor of  claim 52 , wherein the boundary is a proximal boundary. 
     
     
         54 . A bone anchor to anchor an elongated implant to a patient bone and threadably engage with a closure plug, the bone anchor further to couple with a tool comprising an attachment structure, the bone anchor comprising:
 an anchoring member comprising a distal portion and a proximal portion opposite the distal portion, the distal portion to attach to the patient bone in an anchoring manner; and   a head coupled to the proximal portion of the anchoring member, the head to couple to the elongated implant, the head comprising:
 a proximal end and a distal end opposite the proximal end, the proximal portion of the anchoring member extending into the distal end such that the head is coupled to the proximal portion of the anchoring member; 
 a first arm and a second arm spaced apart from the first arm to define a channel to receive the elongated implant to couple the head to the elongated implant, the channel extending distally from the proximal end; 
 a helically wound thread defined in an inner surface of the channel, the inner surface facing radially inward towards a longitudinal center axis of the head, the helically wound thread to threadably engage with the closure plug when the closure plug is received in the channel; 
 an outer surface facing radially outward relative to the longitudinal center axis of the head, the outer surface being on the first arm; and 
 a horizontal radiused slot near the proximal end of the head and extending along at least a portion of the outer surface in a direction perpendicular to the longitudinal center axis of the head, the slot to receive the attachment structure when the bone anchor is coupled to the tool; 
   wherein the proximal end comprises a surface perpendicular to the outer surface:   wherein the horizontal radiused slot is closer in proximity to the proximal end than to the distal end; and   wherein a proximal boundary of the horizontal radiused slot comprises an undercut defining a proximal projecting recess of the horizontal radiused slot.   
     
     
         55 . The bone anchor of  claim 54 , wherein the recess of the slot is to interact with the attachment structure to prevent radially outward displacement of the attachment structure from the slot in which the attachment structure is received. 
     
     
         56 . A bone anchor to anchor an elongated implant to a patient bone and threadably engage with a closure plug, the bone anchor further to couple with a tool comprising an attachment structure, the bone anchor comprising:
 an anchoring member comprising a distal portion and a proximal portion opposite the distal portion, the distal portion to attach to the patient bone in an anchoring manner; and   a head coupled to the proximal portion of the anchoring member, the head to couple to the elongated implant, the head comprising:
 a proximal end and a distal end opposite the proximal end, the proximal portion of the anchoring member extending into the distal end such that the head is coupled to the proximal portion of the anchoring member; 
 a first arm and a second arm spaced apart from the first arm to define a channel to receive the elongated implant to couple the head to the elongated implant, the channel extending distally from the proximal end; 
 a helically wound thread defined in an inner surface of the channel, the inner surface facing radially inward towards a longitudinal center axis of the head, the helically wound thread to threadably engage with the closure plug when the closure plug is received in the channel; 
 an outer surface facing radially outward relative to the longitudinal center axis of the head, the outer surface being on the first arm; and 
 a horizontal radiused slot near the proximal end of the head and extending along at least a portion of the outer surface in a direction perpendicular to the longitudinal center axis of the head, the slot to receive the attachment structure when the bone anchor is coupled to the tool; and 
   wherein the horizontal radiused slot comprises a planar boundary perpendicular to the longitudinal center axis of the head and perpendicularly intersecting the outer surface.   
     
     
         57 . A bone anchor to anchor an elongated implant to a patient bone and threadably engage with a closure plug, the bone anchor further to couple with a tool comprising an attachment structure near a lower end of the tool, the bone anchor comprising:
 an anchoring member comprising a distal portion and a proximal portion opposite the distal portion, the distal portion to be attached to the patient bone in an anchoring manner; and   a head to be coupled to and located near the proximal portion of the anchoring member and to couple to the elongated implant, the head comprising:
 a proximal region with a proximal end, and a distal region opposite the proximal end, the proximal portion of the anchoring member extending distally from the distal region of the head; 
 a first arm and a second arm spaced apart from the first arm to define a channel therebetween to receive the elongated implant to couple the head to the elongated implant, the channel extending distally from the proximal end of the head; 
 a helically wound thread defined in an inner surface on opposite sides of the channel, the inner surface facing radially inward towards a longitudinal center axis of the head, the helically wound thread to threadably engage with the closure plug when the closure plug is received in the channel; 
 an outer surface facing radially outward relative to the longitudinal center axis of the head, the outer surface being on at least the first arm; and 
 a horizontal radiused slot extending along at least a portion of the outer surface in a direction perpendicular to the longitudinal center axis of the head and radially spaced therefrom, the slot to receive the attachment structure when the bone anchor is coupled to the tool, the slot located near the proximal end of the head, and the proximal end of the head having a top surface thereon 
   wherein the horizontal radiused slot comprises a recessed overhanging configuration at a proximal boundary of the horizontal radiused slot.   
     
     
         58 . A bone anchor to anchor an elongated implant to a patient bone and threadably engage with a closure plug, the bone anchor further to couple with a tool comprising an attachment structure near a lower end of the tool, the bone anchor comprising:
 an anchoring member comprising a distal portion and a proximal portion opposite the distal portion, the distal portion to be attached to the patient bone in an anchoring manner; and   a head to be coupled to and located near the proximal portion of the anchoring member and to couple to the elongated implant, the head comprising:
 a proximal region with a proximal end, and a distal region opposite the proximal end, the proximal portion of the anchoring member extending distally from the distal region of the head; 
 a first arm and a second arm spaced apart from the first arm to define a channel therebetween to receive the elongated implant to couple the head to the elongated implant, the channel extending distally from the proximal end of the head; 
 a helically wound thread defined in an inner surface on opposite sides of the channel, the inner surface facing radially inward towards a longitudinal center axis of the head, the helically wound thread to threadably engage with the closure plug when the closure plug is received in the channel; 
 an outer surface facing radially outward relative to the longitudinal center axis of the head, the outer surface being on at least the first arm; and 
 a horizontal radiused slot extending along at least a portion of the outer surface in a direction perpendicular to the longitudinal center axis of the head and radially spaced therefrom, the slot to receive the attachment structure when the bone anchor is coupled to the tool, the slot located near the proximal end of the head, and the proximal end of the head having a top surface thereon 
   wherein the horizontal radiused 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.   
     
     
         59 . The bone anchor of  claim 58 , 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. 
     
     
         60 . The bone anchor of  claim 59 , wherein the free end and the radially outer extent interact to inhibit the attachment structure from radially outward displacement. 
     
     
         61 . The bone anchor of  claim 57 , wherein the bone screw is a polyaxial bone screw.