System, instrumentation and method for spinal fixation using minimally invasive surgical techiques
View Patent ↗A pedicle screw tower having a guide chute, open at both ends, affixed to the exterior of the main body of the tower. The guide chute extends the length of the tower and is curved inwardly at its bottom such that the exit direction is at approximately 90 degrees to and facing the central axis of tower. A guide cable is passed into and through the guide chute such that it is directed across the tower to an adjacent tower.
1. A pedicle screw tower comprising:
a tubular, elongated main body, open at both ends and comprising an axial slot, said main body defining a central axis;
a hollow guide chute comprising a top opening isolated from and not in direct communication with said ends of said main body, and a bottom opening in direct communication with said main body, said guide chute open only at said top and bottom openings, said guide chute affixed to said main body and having a diameter smaller than the diameter of said main body, said guide chute defining a bore having an upper portion parallel to, isolated from and not in direct communication with said main body and a lower portion curved at its bottom approximately 90 degrees toward the central axis of said main body and in direct communication with said main body through said bottom opening, such that said bore provides a passageway from said top opening through said bottom opening into said main body, whereby a guide cable inserted into said top opening, through said bore and past said bottom opening passes across said main body and through said axial slot.
2. The tower of claim 1 , wherein said guide chute is positioned externally to said main body and is affixed to the exterior of said main body with a mounting flange extending between said guide chute and said main body.
3. The tower of claim 2 , wherein said mounting flange is aligned parallel to said central axis of said main body.
4. The tower of claim 1 , wherein said guide chute extends the full length of said main body.
5. The tower of claim 1 , wherein said bottom opening faces transverse to the central axis of said main body.
6. The tower of claim 1 , further whereby said guide chute is adapted to receive a guide cable inserted axially into said top opening and extending laterally from said bottom opening.
7. The tower of claim 1 , wherein said axial slot extends the full length of said main body.
8. A method of advancing a guide cable through a first pedicle screw tower comprising the steps of:
providing a tubular, elongated main body, open at both ends and comprising an axial slot, said main body defining a central axis and a main body passageway; and a hollow guide chute having a diameter smaller than the diameter of said main body and comprising a top opening, a bottom opening and a bore extending from said top opening to said bottom opening, said guide chute positioned externally to said main body, said bore having an upper portion parallel to said central axis of said main body and a lower portion curved at its bottom approximately 90 degrees toward the central axis of said main body, said bore defining a bore passageway extending from said top opening through said bottom opening into said main body, wherein said bore passageway is isolated from said main body passageway except at said bottom opening;
connecting said tower to a pedicle screw; and
inserting a guide cable into said top opening and advancing said guide cable through said guide chute and out from said bottom opening into said main body and toward and across said central axis and then out from said main body through said axial slot.
9. The method of claim 8 further comprising the steps of:
providing a second pedicle screw tower connected to a second pedicle screw;
further advancing said guide cable from said pedicle screw tower into said second pedicle screw tower; and
grasping said guide cable within said second pedicle tower and pulling said guide cable from said second pedicle screw tower.
10. A pedicle screw tower comprising:
a tubular, elongated main body, open at both ends and comprising an axial slot, said main body defining a central axis and a main body passageway;
a hollow guide chute having a diameter smaller than the diameter of said main body and comprising a top opening, a bottom opening and a bore extending from said top opening to said bottom opening, said guide chute positioned externally to said main body, said bore having an upper portion parallel to said central axis of said main body and a lower portion curved at its bottom approximately 90 degrees toward the central axis of said main body, said bore defining a bore passageway extending from said top opening through said bottom opening into said main body, wherein said bore passageway is isolated from said main body passageway except at said bottom opening.
11. The tower of claim 10 , wherein said guide chute is affixed to the exterior of said main body with a mounting flange aligned parallel to said central axis of said main body.
12. The tower of claim 10 , further whereby said guide chute is adapted to receive a guide cable inserted axially into said top opening and extending laterally from said bottom opening into said main body.