Percutaneous technique and implant for expanding the spinal canal
Expanding a spinal canal by drilling a cylindrical passage in each pedicle of a vertebra, making a circumferential pedicle cut (osteotomy) through each pedicle from within the passage, separating each pedicle cut by inserting an implant into the passage to distract the pedicle cut (i.e., lengthen the pedicle) to expand the spinal canal, and securing each pedicle cut, allowing the vertebra to heal with the spinal canal expanded. The implant can include an outer sleeve, an inner bolt, and expandable flanges. The outer sleeve includes an upper and a lower portion, with the expandable flanges therein. Rotation of the inner bolt causes the upper and lower portions of the outer sleeve to separate, causing the pedicle cut to widen and the expandable flanges to radially extend into and stabilize the widened pedicle cut for expansion of the spinal canal.
1. An implant for expanding a spinal canal, comprising:
an outer sleeve having an upper portion and a lower portion; and
an inner bolt in communication with the outer sleeve, wherein movement of the inner bolt in relation to the outer sleeve causes the inner bolt to translate the upper portion away from the lower portion, about a vertebral cut, to widen the vertebral cut and to thereby expand the spinal canal.
2. The implant of claim 1 , wherein the vertebral cut is located in a pedicle of a vertebra, and widening the vertebral cut elongates the pedicle, thereby increasing a diameter of the spinal canal.
3. The implant of claim 1 , wherein the vertebral cut is located in a lumbar vertebra.
4. The implant of claim 1 , wherein the inner bolt is adapted to threadably engage at least a portion of an inner channel of the outer sleeve.
5. The implant of claim 1 , wherein the upper portion and the lower portion include external threads to engage a vertebra about each side of the vertebral cut, the upper portion engaging one side of the vertebral cut and the lower portion engaging another side of the vertebral cut.
6. The implant of claim 1 , wherein the inner bolt includes external threads that engage internal threads of at least the upper portion.
7. The implant of claim 1 , wherein the inner bolt includes external threads capable of engaging internal threads within at least a portion of the upper portion and the lower portion.
8. The implant of claim 1 , wherein the inner bolt threadably engages an inner channel of the upper portion to translate the upper portion away from the lower portion about the vertebral cut to widen the vertebral cut.
9. The implant of claim 8 , wherein the inner bolt, after threadably engaging the inner channel of the upper portion, bears against the lower portion, to translate the upper portion away from the lower portion about the vertebral cut to widen the vertebral cut.
10. The implant of claim 8 , wherein the inner bolt, after threadably engaging the inner channel of the upper portion, communicates in a bearing relationship with the lower portion, to translate the upper portion away from the lower portion about the vertebral cut to widen the vertebral cut.
11. The implant of claim 1 , wherein movement of the inner bolt causes an end of the inner bolt to abut the lower portion, separating the upper portion from the lower portion to widen the vertebral cut.
12. The implant of claim 1 , wherein the upper portion is mechanically secured to the lower portion after widening of the vertebral cut to maintain the widened vertebral cut.
13. The implant of claim 1 , further comprising at least one flange that projects radially from between the upper portion and the lower portion, into the widening vertebral cut, during translation of the upper portion away from the lower portion.
14. The implant of claim 13 , wherein the at least one flange secures a width of the widened vertebral cut.
15. The implant of claim 14 , wherein the inner bolt secures the upper portion to the lower portion about the at least one flange to maintain the widened vertebral cut.
16. The implant of claim 13 , wherein the at least one expandable flange includes osteogenic material to assist with healing of the vertebral cut.
17. The implant of claim 1 , further comprising a plurality of expandable flanges housed within the outer sleeve, wherein movement of the inner bolt in relation to the outer sleeve causes the expandable flanges to radially extend outward, beyond an exterior of the outer sleeve, during translation of the upper portion away from the lower portion.
18. The implant of claim 17 , wherein the expandable flanges are further housed within the upper portion.
19. The implant of claim 17 , wherein the expandable flanges are movably attached to the outer sleeve, wherein movement of the inner bolt causes a distal end of the inner bolt to bear against a respective tip of each expandable flange to radially extend each expandable flange outward beyond an exterior of the outer sleeve and into the vertebral cut, thereby stabilizing the vertebral cut.
20. The implant of claim 19 , wherein the inner bolt, after radially extending the expandable flanges into the vertebral cut, mechanically engages the lower portion to positionally secure the upper portion to the lower portion, thereby securing the vertebral cut in a widened position.