Break-off screw extensions

Abstract

The present invention provides minimally invasive devices and methods for delivering a spinal connector to one or more spinal anchor sites in a patient's spinal column. In one embodiment, a spinal implant and access device is provided that includes a U-shaped receiver member, a bone-engaging member, and an extension member. The U-shaped receiver member can have a recess formed therein that is adapted to seat a spinal connector. The bone-engaging member can extend distally from the receiver member and it can be adapted to engage bone to thereby mate the receiver member to bone. The extension member can extend proximally from the receiver member and it can include a frangible portion formed thereon that is adapted to break when a predetermined force is applied thereto thereby allowing at least a portion of the extension member to be separated from the receiver member.

1 - 21 . (canceled) 
   
   
       22 . A spinal surgical system, comprising:
 a connecting member including an elongated body having a length sized to extend between at least two vertebrae; and   an anchor assembly including a distal anchor engageable to bony structure and an extended receiver extending proximally from and pivotally coupled to said anchor, said extended receiver including a distal implantation portion adjacent said anchor sized and shaped to receive said connecting member therein, said extended receiver further including a proximal guide portion including a pair of removable arms extending along a central axis, said arms extending proximally from and formed as a single unit with a respective one of a pair of opposite side members of said implantation portion, said arms defining a channel extending therebetween from said implantation portion through proximal ends of said pair of arms, said channel including a thread profile along only a distal portion of said arms, and said channel being sized and shaped to receive said connecting member through said proximal end opening thereof in a transverse orientation to said central axis.   
   
   
       23 . The system of  claim 22 , wherein each of said arms is joined to said respective side member with a break-off region having a wall thickness reduced comparatively to an adjacent wall thickness of said respective arm and said respective side member. 
   
   
       24 . The system of  claim 22 , wherein each of said side members defines an internal thread profile along said implantation portion and each of said arms defines an internal thread profile adjacent a distal end thereof that forms an extension of the thread profile of said side members. 
   
   
       25 . The system of  claim 24 , wherein each of said arms is joined to said respective side member at a break-off region between said internal thread profile of said side members and said internal thread profile of said arms. 
   
   
       26 . The system of  claim 22 , wherein said anchor includes a head pivotally captured in said implantation portion of said extended receiver, said anchor further including a shaft extending through a distal opening through said implantation portion for engaging the bony structure. 
   
   
       27 . The system of  claim 26 , further comprising a crown positioned about said head of said anchor in said implantation portion. 
   
   
       28 . The system of  claim 27 , further comprising a second anchor assembly including a second distal anchor engageable to a second vertebra and a second extended receiver extending proximally from and pivotal relative to said second anchor, said second extended receiver including a distal implantation portion adjacent said second anchor sized and shaped to receive said connecting member therein, said second extended receiver further including a proximal guide portion including a pair of removable arms extending along a central axis proximally from and formed as a single unit with a respective one of a pair of opposite side members of said implantation portion, said arms defining a channel extending therebetween from said implantation portion through proximal ends of said pair of arms, said channel being sized and shaped to receive said connecting member through said proximal end opening thereof in a transverse orientation to said central axis. 
   
   
       29 . The system of  claim 28 , wherein, for each of said extended receivers, each of said side members defines an internal thread profile along said implantation portion and each of said arms of said respective extended receiver defines an internal thread profile adjacent a distal end thereof that forms an extension of the thread profile of said side members, and further comprising:
 first and second engaging members positionable in a respective one of said extended receivers to secure said connecting member in said implantation portion thereof, each of said engaging members including an externally threaded portion threadingly engageable with said internal thread profiles along said arms and said side members of said respective extended receiver.   
   
   
       30 . The system of  claim 28 , wherein said connecting member includes a length sized to extend between at least three vertebrae and further comprising a third anchor assembly including a third distal anchor engageable to a third vertebra and a third extended receiver extending proximally from and pivotal relative to said third anchor, said third extended receiver including a distal implantation portion adjacent said third anchor sized and shaped to receive said connecting member therein, said third extended receiver further including a proximal guide portion including a pair of removable arms extending along a central axis proximally from and formed as a single unit with a respective one of a pair of opposite side members of said implantation portion, said arms defining a channel extending therebetween from said implantation portion through proximal ends of said pair of arms, said channel being sized and shaped to receive said connecting member through said proximal end opening thereof in a transverse orientation to said central axis. 
   
   
       31 . The system of  claim 22 , wherein each of said arms includes a length extending from said respective side member that is at least 30 millimeters. 
   
   
       32 . An anchor assembly for securing an elongate connecting member along the spinal column, comprising:
 a distal anchor for engaging bony structure and an extended receiver extending proximally from said anchor, said extended receiver including a distal implantation portion adjacent said anchor, said implantation portion being sized and shaped to receive the connecting member therein, said extended receiver further including a guide portion extending proximally from said implantation portion along a central axis, wherein said implantation portion includes opposite side members and said guide portion includes opposite arms defining a channel therebetween and said opposite arms each include a distal end formed as a single unit with a respective one of said side members at a break-off region, said break-off region providing a separation location for separation of said arms from said respective side member upon application of a threshold force to said arms, said separation location providing a recessed surface interrupting an internal thread profile extending along said arms and said side members.   
   
   
       33 . The assembly of  claim 32 , wherein said channel extends through and opens at proximal ends of said arms. 
   
   
       34 . The assembly of  claim 33 , wherein said channel is sized and shaped to receive said connecting member through said proximal end opening thereof in a transverse orientation to said central axis. 
   
   
       35 . The assembly of  claim 32 , wherein each of said break-off regions includes a wall thickness reduced comparatively to an adjacent wall thickness of said respective arm and said respective side member. 
   
   
       36 . The assembly of  claim 32 , wherein said recessed surface extends completely about said arm and said side member. 
   
   
       37 . The assembly of  claim 32 , further comprising an engaging member positionable in said extended receiver, said engaging member including an externally threaded portion threadingly engageable with said internal thread profiles along said arms and said side members. 
   
   
       38 . An anchor assembly for securing an elongate connecting member along the spinal column, comprising:
 a distal anchor and an extended receiver extending proximally from said anchor, said extended receiver including a distal implantation portion adjacent said anchor, said extended receiver further including a guide portion extending proximally from said implantation portion along a central axis, wherein said implantation portion includes opposite side members and said guide portion includes opposite arms each defining a channel therebetween for receiving the connecting member therethrough, wherein each of said side members defines an internal thread profile along said implantation portion and each of said arms defines an internal thread profile adjacent a distal end thereof along only a portion of a length of said arm, said internal thread profile forming an extension of the thread profile of said side members, wherein each of said arms is joined to said respective side member as a single unit therewith at a reduced thickness region between said internal thread profiles of said arm and said side member, said reduced thickness region defining a separation location for separation of said arm from said respective side member upon application of a threshold force to said arm.   
   
   
       39 . The assembly of  claim 38 , wherein said anchor is pivotally coupled to said extended receiver. 
   
   
       40 . A method for securing a connecting element along a spinal column, comprising:
 engaging a first anchor assembly to a first vertebra and a second anchor assembly to a second vertebra, the first and second anchor assemblies each including an extended receiver extending proximally from the respective first and second vertebrae through the skin of the patient;   positioning an elongate connecting member through the extended receivers in an orientation generally parallel to the spinal column;   guiding the connecting member along proximal guide portions of the extended receivers and into distal implantation portions of the extended receivers;   securing the connecting member in the implantation portions with engaging members positioned into respective ones of the extended receivers in engagement with the implantation portion thereof; and   removing the guide portions by applying force to each of the guide portions, the force severing the guide portions from the respective implantation portion at a break-off region where the guide portion is formed as a single unit with the implantation portion.   
   
   
       41 . The method of  claim 40 , wherein the guide portions each include a pair of arms and the implantation portions each include a pair of side members, said pair of arms being formed at a distal end thereof as a single unit with a respective one of said side members. 
   
   
       42 . The method of  claim 41 , wherein securing the connecting member includes threadingly advancing the engaging member along an internal thread profile that extends only along a portion of a length of the guide portion and the implantation portion of the respective extended receiver. 
   
   
       43 . The method of  claim 40 , further comprising pivoting the extended receiver of at least one of the anchor assemblies to a desired position relative to an anchor engaged to the respective vertebra. 
   
   
       44 . The assembly of  claim 38 , wherein said reduced thickness portion forms a recessed surface that extends completely about said arm and said side member. 
   
   
       45 . The assembly of  claim 38 , further comprising an engaging member positionable in said extended receiver, said engaging member including an externally threaded portion threadingly engageable with said internal thread profiles along said arms and said side members. 
   
   
       46 . An anchor assembly for securing an elongate connecting member along the spinal column, comprising:
 a distal anchor engageable to bony structure and an extended receiver extending proximally from and pivotally coupled to said anchor; said extended receiver including a distal implantation portion adjacent said anchor sized and shaped to receive the connecting member therein, said extended receiver further including a proximal guide portion including a pair of removable arms extending along a central axis, said arms extending proximally from and formed as a single unit with a respective one of a pair of opposite side members of said implantation portion, said arms defining a channel extending therebetween from said implantation portion through proximal ends of said pair of arms, said channel including a thread profile along only a distal portion of said arms, and said channel being sized and shaped to receive the connecting member through said proximal end opening thereof in a transverse orientation to said central axis.   
   
   
       47 . The assembly of  claim 46 , wherein each of said arms is joined to said respective side member with a break-off region having a wall thickness reduced comparatively to an adjacent wall thickness of said respective arm and said respective side member. 
   
   
       48 . The assembly of  claim 46 , wherein each of said side members defines an internal thread profile along said implantation portion and each of said arms defines an internal thread profile adjacent a distal end thereof that forms an extension of the thread profile of said side members. 
   
   
       49 . The assembly of  claim 48 , wherein each of said arms is joined to said respective side member at a break-off region between said internal thread profile of said side members and said internal thread profile of said arms. 
   
   
       50 . The assembly of  claim 46 , wherein said anchor includes a head pivotally captured in said implantation portion of said extended receiver, said anchor further including a shaft extending through a distal opening through said implantation portion for engaging the bony structure. 
   
   
       51 . The assembly of  claim 50 , further comprising a crown positioned about said head of said anchor in said implantation portion. 
   
   
       52 . The assembly of  claim 46 , wherein each of said arms includes a length extending from said respective side member that is at least 30 millimeters. 
   
   
       53 . The assembly of  claim 46 , wherein each of said arms is joined to said respective side member with a break-off region having a recessed surface between said respective arm and said respective side member. 
   
   
       54 . The assembly of  claim 53 , wherein said recessed surface extends completely about said arm and said side member. 
   
   
       55 . The assembly of  claim 46 , wherein each of said side members defines an internal thread profile along said implantation portion and further comprising an engaging member positionable in said extended receiver, said engaging member including an externally threaded portion threadingly engageable with said internal thread profiles along said arms and said side members.