Methods and apparatus for provision of therapy to adjacent motion segments

• US 20060058800A1
• Filed: 08/13/2005
• Published: 03/16/2006
• Est. Priority Date: 12/03/2002
• Status: Active Grant

• Current Assignee: Mis Ip Holdings LLC
• Original Assignee: TranS1 Incorporated (Baxano Surgical, Inc.)
• Inventors: Assell, Robert L., Cragg, Andrew H., Wessman, Bradley J., Ainsworth, Stephen D., Dickhudt, Eugene A., Schwarz, Tawney A.
• Granted Patent: US 7,776,042 B2
• Time in Patent Office: Days
• US Class Current: 606/86.A
• CPC Class Codes: A61B 17/70 Spinal positioners or stabilisers ; Bone stabilisers comprising fluid filler in an implant
• CPC Class Codes: A61B 17/8645 Headless screws, e.g. ligament interference screws
• CPC Class Codes: A61B 17/8875 Screwdrivers, spanners or wrenches
• CPC Class Codes: A61B 2017/0256 for the spine

Abstract

Disclosed are methods and apparatus for the provision of spinal therapy to two or more adjacent motion segments accessed through a trans-sacral approach. The spinal therapies include fusion and dynamic stabilization with and without a distraction of the most cephalad motion segment of the two or more adjacent motion segments provided therapy. The disclosure includes methods and apparatus to impart a distraction on a second more caudal motion segment after providing therapy to the more cephalad motion segment. Related concepts for the extraction of previously inserted devices and the delivery and removal of plugs for plugging the interior cavities of implantable devices are disclosed.

Claims

1. A method to axially distract a first intervertebral disc space between a first vertebral body and a second vertebral body and then axially distract a second intervertebral disc space between the second vertebral body and a third vertebral body, comprising the steps:

inserting a distal end of a distal rod through the third vertebral body, the second intervertebral disc space, the second vertebral body, and into the first intervertebral disc space through a previously formed channel;

rotating the distal rod so that like-handed thread sets on the distal rod engage with the first vertebral body and the second vertebral body, the thread pitch of a first set of threads engaging with the first vertebral body being finer in pitch than the thread pitch of a second set of threads engaging with the second vertebral body so that rotation of the distal rod causes axial distraction of the engaged first vertebral body and the engaged second vertebral body relative to each other;

inserting a distal end of a proximal rod through the third vertebral body and into the second intervertebral disc space through the previously formed channel by rotating the proximal rod to engage a third set of threads on the proximal end of the proximal rod with the third vertebral body; and

wherein

continued rotation of the proximal rod engages the distal end of proximal rod against the proximal end of the distal rod, the rotation of the proximal rod distracting the third vertebral body relative to the second vertebral body engaged with the distal rod.

2. The method of claim 1 wherein the continued rotation of the proximal rod engages the distal end of proximal rod against the proximal end of the distal rod such that the centerline of the longitudinal axis of the proximal rod is in alignment with the centerline of the longitudinal axis of the distal rod.

3. The method of claim 1 wherein the distal rod and the proximal rod are axially implantable and deployed via a trans-sacral approach through an exchange cannula over a guide pin that maintains the axial alignment of the rods.

4. The method of claim 1 further comprising a preliminary step of creating the channel for use in a trans-sacral approach by boring a channel into and through the anterior face of the sacrum.

5. The method of claim 1 wherein the step of continuing the rotation of the proximal rod to distract the third vertebral body relative to the second vertebral body does not alter the previously imposed distraction of the second vertebral body relative to the first vertebral body.

6. The method of claim 1 further comprising the preliminary step of creating the channel with a caudal to cephalad sequence of vertebral body bores of decreasing cross sectional area for cross sections taken perpendicular to the longitudinal axis of the channel such that the vertebral body bores are sized relative to the major diameters of the first set of threads, the second set of threads and the third set of threads allowing cephalad axial advancement of rods of increasing major thread diameters through the channel without cross-threading.

7. The method of claim 6 wherein the preliminary step of preparing the channel includes drilling into the first vertebral body a bore sized to receive the minor diameter of the first set of threads and wherein the major diameter of the first set of threads can be rotated to engage the first vertebral body.

8. The method of claim 1 wherein:

the second set of threads on the distal rod for engaging with the second vertebral body and the third set of threads on the proximal rod for engagement with the third vertebral body are the same type so that the second set of threads pass through the third vertebral body as the distal rod is rotating to advance the distal rod through the third vertebral body as part of the step of inserting the distal end of the distal rod through the third vertebral body, the second intervertebral disc space, the second vertebral body and into the first intervertebral disc space through the previously formed channel; and

the step of inserting the distal end of the proximal rod through the third vertebral body uses a keying process to cause the engagement of the third set of threads into a thread path cut into the third vertebral body by the second set of threads.

9. The method of claim 1 wherein the distal rod is rotated in one particular direction to increase the axial distraction of the first intervertebral disc space and the proximal rod is rotated in the opposite direction to increase the axial distraction in the second intervertebral disc space.

10. The method of claim 1 wherein the distal rod is rotated in one particular direction to increase the axial distraction of the first intervertebral disc space and the proximal rod is rotated in the same direction to increase the axial distraction in the second intervertebral disc space as the first set of threads, the second set of threads and the third set of threads all have the same handedness.

11. The method of claim 1 wherein the first vertebral body is the L4 vertebra, the second vertebral body is the L5 vertebra, and the third vertebral body is the sacrum.

12. The method of claim 1 wherein the first vertebral body is the L3 vertebra, the second vertebral body is the L4 vertebra, and the third vertebral body is the L5 vertebra.

13. The method of claim 1 further comprising applying a spinal therapy to treat a first motion segment comprising the first vertebral body, a first intervertebral disc, and the second vertebral body after at least partial nucleectomy and distraction through the insertion of material into the first intervertebral disc space.

14. The method of claim 1 further comprising applying a spinal therapy to treat a first motion segment comprising the first vertebral body, a first intervertebral disc, and the second vertebral body after at least partial nucleectomy and distraction through the insertion of a device into the first motion segment.

15. The method of claim 13 wherein the spinal therapy acts to fuse together a first motion segment comprising the first vertebral body, a first intervertebral disc, and the second vertebral body and the material inserted into the first intervertebral disc space promotes fusion.

16. The method of claim 15 further comprising the additional step of applying a spinal therapy to treat a second motion segment comprising the second vertebral body, a second intervertebral disc, and the third vertebral body after at least a partial nucleectomy and distraction of the second motion segment through the insertion of material into the second intervertebral disc space wherein the spinal therapy acts to fuse together the second motion segment and the material inserted into the second intervertebral disc space promotes fusion.

17. The method of claim 13 wherein the spinal therapy provides dynamic stabilization of a first motion segment comprising the first vertebral body, a first intervertebral disc, and the second vertebral body and the material inserted into the first intervertebral disc space expands a flexible portion of the distal rod.

18. The method of claim 17 further comprising the additional step of applying a spinal therapy to treat a second motion segment comprising the second vertebral body, a second intervertebral disc, and the third vertebral body after at least partial nucleectomy and distraction of the second intervertebral disc space, the spinal therapy comprising the insertion of material into the second intervertebral disc space wherein the spinal therapy acts to fuse together the second motion segment and the material inserted into the second intervertebral disc space promotes fusion.

19. The method of claim 17 further comprising the additional step of applying a spinal therapy to treat a second motion segment comprising the second vertebral body, a second intervertebral disc, and the third vertebral body after at least partial nucleectomy and distraction of the second intervertebral disc space through the insertion of material into the second intervertebral disc space wherein the spinal therapy provides for dynamic stabilization of a second motion segment.

20. The method of claim 13 further comprising inserting a plug prior to inserting the distal end of the proximal rod, the plug inserted through the third vertebral body, the second intervertebral disc space, and into the cavity in the proximal end of the distal rod in fluid communication with the first intervertebral disc space after the insertion of material into the first intervertebral disc space in order to retain the material within the first intervertebral disc space.

21. The method of claim 20 wherein the step of inserting a plug is comprised of the following sub-steps:

attaching the plug to a distal end of a retention rod that runs through the interior of a plug driver to a retention rod disengagement actuator; and

inserting the distal end of the plug driver along with the attached plug through the third vertebral body, the second intervertebral disc space, and into the cavity in the proximal end of the distal rod;

and is followed by these steps;

rotating a plug driver along with the attached plug to engage the plug with the distal rod;

operating the retention rod disengagement actuator to detach the plug from the distal end of the retention rod; and

withdrawing the plug driver from the channel.

22. The method of claim 1 further comprising inserting of a distal end of an inter-rod plug through a lumen in the proximal rod into the a cavity in the distal rod before a threaded portion on the exterior of the inter-rod plug is engaged.

23. The method of claim 22 wherein the step of inserting the distal end of the inter-rod plug through the lumen in the proximal rod into the cavity in the distal rod before the threaded portion on the exterior of the inter-rod plug is engaged is comprised of the following sub-steps:

attaching the proximal end of the inter-rod plug to a distal end of a retention rod that runs through the interior of a plug driver to a retention rod disengagement actuator; and

inserting the distal end of the plug driver along with the attached inter-rod plug through the third vertebral body, the second intervertebral disc space, and through the lumen in the proximal rod into the cavity in the distal rod;

and is followed by these steps;

rotating the inter-rod plug with the plug driver to engage the threaded portion on the exterior of the inter-rod plug within the distal rod;

operating the retention rod disengagement actuator to detach the inter-rod plug from the distal end of the retention rod; and

withdrawing the plug driver from the channel.

24. The method of claim 22 wherein the threaded portion of the inter-rod plug engages a set of female threads cut in a cavity in the distal rod.

25. The method of claim 22 wherein the threaded portion of the inter-rod plug engages a set of female threads in a cavity of a plug previously inserted into the distal distraction rod.

26. The method of claim 1 wherein the step of rotating the proximal rod to engage the third set of threads on the proximal end of the proximal rod with the third vertebral body is achieved by engaging the distal end of a rod driver into a cavity in the proximal end of the proximal rod, the cavity comprising a socket for receipt of a corresponding polygonal driver for the transfer of rotational forces from the driver to the proximal rod;

the method further comprising the additional steps of removing the inserted proximal rod after distraction of the second intervertebral disc space through;

placing the distal tip of a disengagement tool adjacent to a portion of the cavity in the proximal end of the proximal rod, the portion of the cavity having a left-handed threaded section for receipt of a corresponding set of threads on a distal end of the disengagement tool;

rotating the disengagement tool counterclockwise to engage the disengagement tool with the threaded section in the proximal rod;

continuing the counterclockwise rotation after completion of the threaded engagement to impart a rotation to the proximal rod to disengage the proximal rod from the third vertebral body such that once disengaged from the third vertebral body but still engaged with the disengagement tool, the disengaged proximal rod can be removed with the distal end of the disengagement tool from the channel.

27. The method of claim 26 wherein the steps of removing the inserted proximal rod after distraction of the second intervertebral disc space further comprises:

engaging the distal end of the driver into the cavity in the proximal end of the proximal rod in the socket and using the driver to rotate the proximal rod in the opposite direction from the direction of rotation that imposes distraction before engaging the disengagement tool with the proximal rod.

28. A method to axially distract a second intervertebral disc space between a second vertebral body and a third vertebral body after inserting a distal device into the second vertebral body and at least a portion of the first intervertebral disc space between the second vertebral body and the first vertebral body, comprising the steps:

inserting a distal end of a distal device through the third vertebral body, the second intervertebral disc space, the second vertebral body, and into the first intervertebral disc space through a previously formed channel by rotating the distal device so that threads on the proximal end of the distal device engage with the second vertebral body;

inserting a distal end of a proximal device through the third vertebral body and into the second intervertebral disc space through the previously formed channel by rotating the proximal device to engage a set of threads on the proximal end of the proximal device with the third vertebral body; and

wherein continuing rotation of the proximal device engages the distal end of the proximal device with the proximal end of the distal device without causing rotation of the distal device engaged in the second vertebral body, the rotation of the proximal device moving the third vertebral body relative to the second vertebral body engaged with the distal device to distract the second intervertebral disc space.

29. The method of claim 28 wherein the distal device and the proximal device are axially implantable and deployed via a trans-sacral approach through an exchange cannula over a guide pin that maintains the axial alignment of the device.

30. The method of claim 28 further comprising a preliminary step of creating the channel for use in a trans-sacral approach by boring a channel through the anterior face of the sacrum.

31. The method of claim 28 wherein the step of rotating the distal device causes threads to engage with the first vertebral body and the second vertebral body, the thread pitch of the threads engaging with the first vertebral body having the same pitch and handedness of rotation as the threads engaging with the second vertebral body such that rotation of the distal device causes the movement of the distal device in the cephalad direction without altering the axial distance between the first vertebral body and the second vertebral body.

32. The method of claim 28 wherein:

the threads on the proximal end of the distal device for engaging with the second vertebral body and set of threads on the proximal device for engagement with the third vertebral body are the same type so that the threads on the proximal end of the distal device pass through the third vertebral body as the distal device is rotating to advance the distal device through the third vertebral body as part of the step of inserting the distal end of the distal device through the third vertebral body, the second intervertebral disc space, the second vertebral body and into the first intervertebral disc space through the previously formed channel; and

the step of inserting the distal end of the proximal device through the third vertebral body uses a keying process to cause the engagement of the set of threads on the proximal device into a thread path cut into the third vertebral body by the at least one set of threads on the distal device.

33. The method of claim 28 wherein:

the step of rotating the distal device causes the threads on the proximal end of the distal device to engage with the second vertebral body and the distal end of the distal device advances into the first intervertebral disc space for subsequent provision of therapy without a threaded engagement of the distal end of the distal device in the first vertebral body; and

the step of inserting the distal end of the proximal device through the third vertebral body and into the second intervertebral disc space through the previously formed channel does not occur until after a portion of the distal device in the first intervertebral disc space is expanded as part of mobility management therapy for the first intervertebral disc space.

34. The method of claim 33 wherein the distal device in the at least a portion of the first intervertebral disc space is expanded to press against the first vertebral body and to move through use of hydraulics the first vertebral body in a direction relative to the second vertebral body such that the movement includes an axial distraction of the first vertebral body relative to the second vertebral body.

35. The method of claim 28 wherein the first vertebral body is the L4 vertebra, the second vertebral body is the L5 vertebra, and the third vertebral body is the sacrum.

36. The method of claim 28 wherein the first vertebral body is the L3 vertebra, the second vertebral body is the L4 vertebra, and the third vertebral body is the L5 vertebra.

37. The method of claim 28 further comprising applying a spinal therapy to treat a first motion segment comprising the first vertebral body, a first intervertebral disc, and the second vertebral body after at least a partial nucleectomy and distraction of the second intervertebral disc space, through the insertion of material into the first intervertebral disc space.

38. The method of claim 37 wherein the spinal therapy acts to fuse together a first motion segment comprising the first vertebral body, a first intervertebral disc, and the second vertebral body and the material inserted into the first intervertebral disc space promotes fusion.

39. The method of claim 38 further comprising the additional step of applying a spinal therapy to treat a second motion segment comprising the second vertebral body, a second intervertebral disc, and the third vertebral body after at least a partial nucleectomy and distraction of the second intervertebral disc space, the therapy comprising the insertion of material into the second intervertebral disc space wherein the spinal therapy acts to fuse together the second motion segment and the material inserted into the second intervertebral disc space promotes fusion.

40. The method of claim 37 wherein the spinal therapy provides for dynamic stabilization of a first motion segment comprising the first vertebral body, a first intervertebral disc, and the second vertebral body and the material inserted into the first intervertebral disc space expands a flexible portion of the distal device.

41. The method of claim 40 further comprising the additional step of applying a spinal therapy to treat a second motion segment comprising the second vertebral body, a second intervertebral disc, and the third vertebral body after at least a partial nucleectomy and distraction of the second intervertebral disc space, the spinal therapy comprising the insertion of material into the second intervertebral disc space wherein the spinal therapy acts to fuse together the second motion segment and the material inserted into the second intervertebral disc space promotes fusion.

42. The method of claim 40 further comprising the additional step of applying a spinal therapy to treat a second motion segment comprising the second vertebral body, a second intervertebral disc, and the third vertebral body after at least a partial nucleectomy and distraction of the second intervertebral disc space, the spinal therapy comprising the insertion of material into the second intervertebral disc space wherein the spinal therapy provides dynamic stabilization of the second motion segment.

43. The method of claim 37 further comprising insertion of a plug prior to inserting the distal end of the proximal device, the plug inserted through the third vertebral body, the second intervertebral disc space, and into the cavity in the proximal end of the distal device in fluid communication with the first intervertebral disc space after the insertion of material into the first intervertebral disc space in order to retain the material within the first intervertebral disc space.

44. The method of claim 43 wherein the step of inserting a plug is comprised of the following sub-steps:

attaching the plug to a distal end of a retention rod that runs through the interior of a plug driver to a retention rod disengagement actuator; and

inserting the distal end of the plug driver along with the attached plug through the third vertebral body, the second intervertebral disc space, and into the cavity in the proximal end of the distal device;

and is followed by these steps;

rotating a plug driver along with the attached plug to engage the plug with the distal device;

operating the retention rod disengagement actuator to detach the plug from the distal end of the retention rod; and

withdrawing the distal end of the plug driver from the channel.

45. The method of claim 28 further comprising the insertion of a distal end of an inter-device plug through a lumen in the proximal device into a cavity in the distal device before a threaded portion of the exterior of the inter-device plug is engaged.

46. The method of claim 45 wherein the step of inserting the distal end of the inter-device plug through the lumen in the proximal device into the cavity in the distal device before the threaded portion of the exterior of the inter-device plug is engaged is comprised of the following sub-steps:

attaching the proximal end of the inter-device plug to a distal end of a retention rod that runs through the interior of a driver to a retention rod disengagement actuator; and

inserting the distal end of the driver along with the attached inter-device plug through the third vertebral body, the second intervertebral disc space, and through the lumen in the proximal device and into the cavity in the distal device;

and is followed by these steps;

rotating the inter-device plug with the driver to engage the threaded portion of the exterior of the inter-device plug within the distal device;

operating the retention rod disengagement actuator to detach the inter-device plug from the distal end of the retention rod; and

withdrawing the driver from the channel.

47. The method of claim 45 wherein the threaded portion of the inter-device plug engages a set of female threads cut in the cavity in the distal device.

48. The method of claim 45 wherein the threaded portion of the inter-device plug engages a set of female threads in the cavity of a plug previously inserted into the distal device.

49. A method to distract a first intervertebral disc space between a first vertebral body and a second vertebral body, then distract a second intervertebral disc space between the second vertebral body and a third vertebral body, and then distract a third intervertebral disc space between the third vertebral body and a fourth vertebral body, comprising the steps:

inserting a distal end of a distal distraction rod through the fourth vertebral body, the third intervertebral disc space, the third vertebral body, the second intervertebral disc space, the second vertebral body, and into the first intervertebral disc space through a previously formed channel;

rotating the distal distraction rod so that threads on the distal distraction rod engage with the first vertebral body and the second vertebral body, the thread pitch of the first set of threads engaging with the first vertebral body having more threads per unit length than the thread pitch of the second set of threads engaging with the second vertebral body so that rotation of the distal distraction rod causes the engaged first vertebral body and the engaged second vertebral body to be moved apart from one another to distract the first intervertebral disc space;

inserting a distal end of a medial distraction rod through the fourth vertebral body, the third intervertebral disc space, the third vertebral body and into the second intervertebral disc space through the previously formed channel;

rotating the medial distraction rod to engage a third set of threads on the medial distraction rod with the third vertebral body;

continuing rotation of the medial distraction rod so that as the medial distraction rod presses against the distal distraction rod, the rotation of the medial distraction rod moves the third vertebral body relative to the second vertebral body engaged with the distal distraction rod to distract the second intervertebral disc space;

inserting a distal end of a proximal distraction rod through the fourth vertebral body and into the third intervertebral disc space through the previously formed channel;

rotating the proximal distraction rod to engage a fourth set of threads on the proximal distraction rod with the fourth vertebral body; and

continuing rotation of the proximal distraction rod so that as the proximal distraction rod presses against the medial distraction rod, the rotation of the proximal distraction rod moves the fourth vertebral body relative to the third vertebral body engaged with the medial distraction rod to distract the third intervertebral disc space.

50. The method of claim 49 further comprising the preliminary step of preparing the channel by creating a channel with a caudal to cephalad sequence of vertebral body bores of decreasing cross sectional area for cross sections taken perpendicular to the long axis of the channel such that the vertebral body bores are sized relative to the major diameters of the first set of threads, the second set of threads and the third set of threads allowing cephalad axial advancement of rods with thread sets of increasing major diameters through the channel without cross threading.

51. The method of claim 49 wherein:

the third second set of threads on the medial distraction rod for engaging with the third vertebral body and the fourth set of threads on the proximal distraction rod for engagement with the fourth vertebral body are the same type so that the third set of threads pass through the fourth vertebral body as the medial distal distraction rod is rotating to advance the distal distraction rod through the fourth vertebral body as part of the step of inserting the distal end of the medial device through the fourth vertebral body, the third intervertebral disc space, the third vertebral body and into the second intervertebral disc space through the previously formed channel; and

the step of inserting the distal end of the proximal distraction rod through the fourth vertebral body uses a keying process to cause the engagement of the fourth set of threads into a thread path cut into the fourth vertebral body by the third set of threads.

52. The method of claim 49 wherein the first vertebral body is the L3 vertebra, the second vertebral body is the L2 vertebra, third vertebral body is the L5 vertebra and the fourth vertebral body is the sacrum.

53. The method of claim 49 wherein the first vertebral body is the L2 vertebra, the second vertebral body is the L3 vertebra, third vertebral body is the L4 vertebra and the fourth vertebral body is the L5 vertebra.

54. A method to distract a second intervertebral disc space between a second vertebral body and a third vertebral body, and then distract a third intervertebral disc space between the third vertebral body and a fourth vertebral body after inserting a device for providing therapy to a first intervertebral disc space between a first vertebral body and the second vertebral body, comprising the steps:

inserting a distal end of a distal device through the fourth vertebral body, the third intervertebral disc space, the third vertebral body, the second intervertebral disc space, the second vertebral body, and into the first intervertebral disc space through a previously formed channel;

rotating the distal device so that threads on the distal device engage with the second vertebral body so that rotation of the distal device causes the distal device to advance cephaladly and into the first intervertebral disc space;

inserting a distal end of a medial device through the fourth vertebral body, the third intervertebral disc space, the third vertebral body and into the second intervertebral disc space through the previously formed channel;

rotating the medial device to engage a set of threads on the medial device with the third vertebral body;

continuing rotation of the medial device so that as the medial device presses against the distal device, the rotation of the medial device moves the third vertebral body relative to the second vertebral body engaged with the distal device to distract the second intervertebral disc space;

inserting a distal end of a proximal device through the fourth vertebral body and into the third intervertebral disc space through the previously formed channel;

rotating the proximal device to engage a set of threads on the proximal device with the fourth vertebral body; and

continuing rotation of the proximal device so that as the proximal device presses against the medial device, the rotation of the proximal device moves the fourth vertebral body relative to the third vertebral body engaged with the medial device rod to distract the third intervertebral disc space.

55. A method of inserting a component into a device previously inserted into a human body through an access channel while maintaining a positive engagement between the component and a driver for the component while the component and the distal tip of the driver move in the access channel to a proximal end of the previously inserted device;

the method comprising;

rotating a threaded section of the distal tip of a retention rod with a rotation actuator located on a portion of the driver that will remain outside of the access channel, the rotation causing a threaded engagement between the distal tip of the retention rod and the proximal end of the component until the component is affixed to the distal end of the driver and engaged with a driver head on the driver that corresponds to a driver receiving section in the proximal end of the component;

inserting the component and the distal end of the driver into the access channel until distal tip of the component is in proper positions for a threaded engagement with the previously inserted device;

using the driver to rotate the driver head to cause rotation of the component to achieve a threaded engagement between the component and the previously inserted device;

rotating the threaded section of the distal tip of the retention rod with the rotation actuator to disengage the threaded attachment between the distal tip of the retention rod and the proximal end of the component; and

after disengaging the retention rod from the component which is now in threaded engagement with the previously inserted device, removing the distal end of the driver from the access channel.

56. The method of claim 55 wherein the disengagement of the threaded attachment between the distal tip of the retention rod and the proximal end of the component is done before the completion of using the driver to rotate the driver head to cause rotation of the component to achieve the threaded engagement between the component and the previously inserted device.

57. The method of claim 55 wherein the disengagement of the threaded attachment between the distal tip of the retention rod and the proximal end of the component is done after the completion of using the driver to rotate the driver head to cause rotation of the component to achieve the threaded engagement between the component and the previously inserted device.

58. The method of claim 55 wherein the driver head is a male driver head on the driver that corresponds to a driver receiving section in a cavity at the proximal end of the component.

59. The method of claim 55 wherein the threaded section of the distal tip of the retention rod is a set of male threads on the distal tip.

60. The method of claim 55 wherein the threaded section of the distal tip is a set of female threads in a bore at the distal tip of the retention rod that engages with a corresponding set of male threads on the proximal end of the component.

61. A spinal device assembly for therapy of at least two adjacent spinal motion segments, the spinal assembly comprising a distal component and a proximal component, the distal component comprising:

an elongate body with anchoring means for engagement with at least a first vertebral body;

a distal end; and

a proximal end adapted to engage the distal end of the proximal component along the centerline of the longitudinal axis of the distal component; and

the proximal component comprising;

a distal end adapted to engage the proximal end of the distal component along the centerline of the longitudinal axis of the proximal component;

a proximal end with anchoring means for engagement with a second, more inferior vertebral body, said proximal end adapted to engage a removable driver that rotates and axially advances the proximal component so that the distal end of the proximal component engages the proximal end of the distal component to impart axial force to the distal component without imparting rotation to the distal component thereby causing distraction of the intervertebral disc space.

62. The spinal device assembly of claim 61 wherein said distal component and said proximal component are adapted for deployment through a channel created through a trans-sacral axial surgical approach.

63. An assembly comprising a distal device and a proximal device, the components of the assembly adapted for delivery by a trans-sacral approach through a channel to adjacent spinal motion segments for imposition of therapy upon two adjacent spinal motion segments such that the distal device is placed more distal to the sacrum than the proximal device;

the distal device comprising;

a distal end;

at least one set of threads for engagement with at least one vertebral body; and

a proximal end with a cavity along the centerline of the longitudinal axis of the distal device, the cavity having an engagement zone;

the proximal device comprising;

a distal end with an extension adapted to fit at least a portion of the extension within the engagement zone in the cavity of the distal device;

a threaded section for engagement with a vertebral body;

a proximal end with a cavity along centerline of the longitudinal axis of the proximal device containing a driver engagement section such that rotational force imparted by a corresponding driver head causes the threaded section of the proximal device to engage with a proximal vertebral body and advance the proximal device towards a previously inserted distal device such that the extension of the proximal device enters into the cavity of the distal device and the proximal device abuts against at least a portion of the surface of the distal device so that further rotation of the proximal device exerts an axial force upon the distal device while rotating the extension relative to the engagement zone to move the distal device and the at least one engaged vertebral body axially away from the proximal vertebral body engaged with the proximal device.

64. The assembly of claim 63 wherein the proximal device further comprises a thrust bearing on the distal end of the proximal device such that upon sufficient axial advancement of the proximal device towards the distal device, the thrust bearing portion of the proximal device abuts against at least a portion of the surface area of the distal device.

65. The assembly of claim 63 wherein the proximal device further comprises a shoulder that surrounds the extension on the distal end of the proximal device such that upon sufficient axial advancement of the proximal device towards the distal device, the shoulder portion of the proximal device abuts against at least a portion of the surface area of the distal device.

66. The assembly of claim 63 wherein upon sufficient axial advancement of the proximal device towards the distal device, the extension of the proximal device abuts against at least a portion of the surface area of the engagement zone in the distal device.

67. The assembly of claim 63 wherein the threaded section of the proximal device comprises cancellous type bone threads with generally flat faces oriented towards the caudal side of the vertebral body.

68. The assembly of claim 63 wherein the distal device is further characterized by having one set of male threads for engagement with a distal vertebral body and a second set of male threads with the same handedness for engagement with a less distal vertebral body.

69. The assembly of claim 68 wherein the first set of male threads and the second set of male threads on the distal device have the same pitch.

70. The assembly of claim 68 wherein the first set of male threads on the distal device has a finer pitch than the second set of male threads on the distal device such that rotation of the distal device after engagement of the first set of threads with the distal vertebral body and the engagement of the second set of threads with the less distal vertebral body causes an axial distraction of the distal vertebral body relative to the less distal vertebral body.

71. The assembly of claim 70 wherein the first set of male threads on the distal device have a smaller major diameter than the second set of male threads on the distal device so that the first set of male threads can pass through a previously formed bore in the less distal vertebral body without the need for rotation of the distal device and the creation of a thread path in the less distal vertebral body.

72. The assembly of claim 70 wherein the rotation of the proximal device while the extension of the proximal device abuts against the at least a portion of the surface of the engagement zone of the distal device does not alter the axial distraction of the distal vertebral body relative to the less distal vertebral body.

73. The assembly of claim 68 wherein the distal device is adapted to provide therapy to a motion segment comprising the distal vertebral body, the less distal vertebral body, and the intervertebral disc space between the distal vertebral body and the less distal vertebral body by insertion of material into the intervertebral disc space through fenestrations in the distal device.

74. The assembly of claim 73 wherein the spinal therapy acts to fuse together the motion segment and the material inserted into the intervertebral disc space promotes fusion.

75. The assembly of claim 73 wherein the spinal therapy provides for dynamic stabilization of the motion segment and the material inserted into the intervertebral disc space expands a flexible portion of the distal device.

76. The assembly of claim 68 further characterized by sizing the lengths of the distal device and the proximal device, and the lengths of the set of threads for engagement with the distal vertebral body, the set of threads for engagement with the less distal vertebral body, and the set of threads on the proximal device for engaging the vertebral body are selected so that the assembly can be positioned to engage the L4 vertebral body, the L5 vertebral body, and the sacrum.

77. The assembly of claim 63 wherein the distal device is provided with a proximal end with a set of threads for engagement with one vertebral body and a distal tip of the distal end for placement in an intervertebral disc space between the one vertebral body and a more distal vertebral body and the distal device is adapted to insert material into the intervertebral disc space between the one vertebral body and the more distal vertebral body.

78. The assembly of claim 77 wherein the distal device further comprises a flexible component in the portion of the distal device intended for placement in the intervertebral disc space between the one vertebral body and the more distal vertebral body;

and the distal device is adapted to insert material into the intervertebral disc space between the one vertebral body and the more distal vertebral body by receiving material through a central axial cavity to expand the flexible component outward from the distal device and into the intervertebral disc space.

79. The assembly of claim 77 wherein the distal device further comprises a flexible component in the portion of the distal device intended for placement in the intervertebral disc space between the one vertebral body and the more distal vertebral body;

and the distal device is adapted to insert material into the intervertebral disc space between the one vertebral body and the more distal vertebral body by receiving material through a central axial cavity to deliver the material into the intervertebral disc space.

80. The assembly of claim 77 wherein the distal device is adapted for use in fusing together the one vertebral body, the intervertebral disc space, and the more distal vertebral body and to insert material into the intervertebral disc space that promotes fusion.

81. The assembly of claim 63 wherein the assembly is further characterized by:

the distal device having the cavity along the centerline of the longitudinal axis in fluid communication with a set of at least one fenestration so that material provided to the proximal end of the distal device can be delivered into an intervertebral disc space;

the distal device having an internal set of threads in the cavity to receive a plug;

a plug placed in the distal device in threaded engagement with the internal set of threads in the distal device such that material delivered into the intervertebral disc space is limited in its ability to ingress back through the fenestration and into the cavity of the distal device.

82. The assembly of claim 81 wherein the assembly is further characterized by:

the proximal device having the cavity along the centerline of the longitudinal axis in fluid communication with a set of at least one fenestration so that material provided to the proximal end of the proximal device can be delivered into an intervertebral disc space;

the proximal device having an internal set of threads in the cavity to receive a plug;

a plug placed in the proximal device in threaded engagement with the internal set of threads in the proximal device such that material delivered into the intervertebral disc space is limited in its ability to ingress back through the fenestration and into the cavity of the proximal device.

83. The assembly of claim 81 wherein the assembly is further characterized by the plug having a cavity on its proximal end with:

an engagement zone for receiving a corresponding driver head so that a driver can impart a rotation to the plug to cause the plug to engage the threads in the distal device; and

a threaded bore to receive a male threaded distal end of a retention rod, so that the male threaded distal tip of the retention rod of a plug driver can be threadedly engaged with the proximal end of the plug before the plug and the distal end of the plug driver are inserted through the trans-sacral approach channel for delivery of the plug to the cavity of the distal device.

84. The assembly of claim 63 wherein:

the cavity in the proximal end of the distal device having a socket for receipt of a corresponding polygonal driver for the transfer of rotational forces from the driver to the distal device to rotate the distal device with respect to the at least one vertebral body;

the cavity in the proximal end of the distal device having a left-handed threaded section for receipt of a corresponding set of threads on a distal end of a disengagement tool so that a disengagement tool can be rotated counterclockwise to engage the disengagement tool with the distal device and after completion of the threaded engagement impart a rotation to the distal device to disengage the distal device from the at least one vertebral body such that once disengaged from the at least one vertebral body but still engaged with the disengagement tool, the disengaged distal device can be removed with the distal end of the disengagement tool from the channel.

85. The assembly of claim 63 wherein:

the driver engagement section in the cavity in the proximal end of the proximal device comprising a socket for receipt of a corresponding polygonal driver for the transfer of rotational forces from the driver to the proximal device to rotate the proximal device with respect to the vertebral body;

the cavity in the proximal end of the proximal device having a left-handed threaded section for receipt of a corresponding set of threads on a distal end of a disengagement tool so that a disengagement tool can be rotated counterclockwise to engage the disengagement tool with the proximal device and after completion of the threaded engagement impart a rotation to the proximal device to disengage the proximal device from the vertebral body such that once disengaged from the vertebral body but still engaged with the disengagement tool, the disengaged proximal device can be removed with the distal end of the disengagement tool from the channel.

86. The assembly of claim 63 further comprising a thrust bearing located between the proximal end of the distal device and the distal end of the proximal device so that rotation of the proximal device causing the proximal device to advance towards the previously inserted distal device imparts an axial force through the thrust bearing to the distal device.

87. The assembly of claim 86 wherein the thrust bearing is a washer-shaped structure formed of a biocompatible polymer with a coefficient of sliding friction between the thrust bearing and proximal device being less than the coefficient of sliding friction between the proximal device and the distal device.

88. The assembly of claim 63 wherein the proximal device and the distal device are joined by a plug with a treaded engagement to maintain the post-operative relative axial positions of the distal and proximal devices.

89. The assembly of claim 88 wherein the assembly is further characterized by the plug having a cavity on its proximal end with:

an engagement zone for receiving a corresponding driver head so that a driver can impart a rotation to the plug to cause the plug to engage the threads to act to maintain the post-operative relative axial positions of the distal and proximal devices; and

a threaded bore to receive a male threaded distal end of a retention rod, so that the male threaded distal tip of the retention rod of a plug driver can be threadedly engaged with the proximal end of the plug before the plug and the distal end of the plug driver are inserted through the trans-sacral approach channel for delivery of the plug to the cavity of the proximal device.

90. The assembly of claim 88 wherein the plug engages with a set of corresponding threads in the cavity along the centerline of the distal device to pull together the distal device and the proximal device.

91. The assembly of claim 88 wherein the plug engages with a set of corresponding threads in a cavity along the centerline of a plug previously inserted in the distal device to pull together the plug and the distal device towards the proximal device.

92. The assembly of claim 63 wherein:

the distal device;

is adapted for use in fusing together a motion segment comprising a vertebral body, an adjacent and more distal vertebral body and the intervertebral disc space between the intervertebral bodies, the distal device having the cavity along the centerline of the longitudinal axis in fluid communication with a set of at least one fenestration so that material provided to the proximal end of the distal device can be delivered into an intervertebral disc space and to insert material into the intervertebral disc space that promotes fusion; and

the proximal device;

is adapted for use in fusing together a motion segment comprising a vertebral body, an adjacent and more distal vertebral body and the intervertebral disc space between the intervertebral bodies, the distal device having the cavity along the centerline of the longitudinal axis in fluid communication with a set of at least one fenestration so that material provided to the proximal end of the distal device can be delivered into an intervertebral disc space and to insert material into the intervertebral disc space that promotes fusion;

such that the assembly can be used in providing fusion therapy to two adjacent motion segments accessed through a trans-sacral approach.

93. The assembly of claim 63 wherein:

the distal device;

further comprises a flexible component in the portion of the distal device intended for placement in the intervertebral disc space between a vertebral body an adjacent and more distal vertebral body and the distal device is adapted to insert material into the intervertebral disc space between a vertebral body and the distal device by receiving material through a central axial cavity to expand the flexible component outward from the distal device and into the intervertebral disc space; and

the proximal device;

is adapted for use in fusing together a motion segment comprising a vertebral body, an adjacent and more distal vertebral body and the intervertebral disc space between the intervertebral bodies, the distal device having the cavity along the centerline of the longitudinal axis in fluid communication with a set of at least one fenestration so that material provided to the proximal end of the distal device can be delivered into an intervertebral disc space and to insert material into the intervertebral disc space that promotes fusion;

such that the assembly can be used in providing therapy to allow dynamic stabilization of a distal motion segment and to provide for fusion of an adjacent and more proximal motion segment, both motion segments accessed through a trans-sacral approach.

94. The assembly of claim 63 wherein:

the distal device further comprises a flexible component in the portion of the distal device intended for placement in the intervertebral disc space between a vertebral body an adjacent and more distal vertebral body and the distal device is adapted to insert material into the intervertebral disc space between a vertebral body and the more distal vertebral body by receiving material through a central axial cavity to expand the flexible component outward from the distal device and into the intervertebral disc space; and

the proximal device further comprises a flexible component in the portion of the proximal device intended for placement in the intervertebral disc space between a vertebral body an adjacent and more distal vertebral body and the proximal device is adapted to insert material into the intervertebral disc space between a vertebral body and a more distal vertebral body by receiving material through a central axial cavity to expand the flexible component outward from the proximal device and into the intervertebral disc space;

such that the assembly can be used in providing therapy to allow dynamic stabilization of both a distal motion segment and an adjacent and more proximal motion segment, both motion segments accessed through a trans-sacral approach.

95. An assembly comprising a distal device and a proximal device, the components of the assembly adapted for delivery by a trans-sacral approach to adjacent spinal motion segments for imposition of therapy upon two adjacent spinal motion segments such that the distal device is placed more distal to the sacrum than the proximal device;

the distal device comprising;

a distal end

at least one set of threads for engagement with at least one vertebral body and

a proximal end with an extension along the centerline of the longitudinal axis of the distal device;

the proximal device comprising;

a distal end with a cavity with an engagement zone adapted to receive at least a portion of the extension of the distal device within the engagement zone in the cavity;

a threaded section for engagement with a vertebral body;

a proximal end with a cavity along centerline of the longitudinal axis of the proximal device containing a driver engagement section such that rotational force imparted by a corresponding driver head causes the threaded section of the proximal device to engage with a proximal vertebral body and advance the proximal device towards a previously inserted distal device such that the extension of the distal device enters into the cavity of the proximal device and the proximal device abuts against at least a portion of the surface distal device so that further rotation of the proximal device exerts an axial force upon the distal device while rotating relative to the distal device to move the distal device and the at least one engaged vertebral body away from the vertebral body engaged with the proximal device.

96. An assembly comprising a distal device, a medial device and a proximal device, the components of the assembly adapted for delivery by a trans-sacral approach through a channel to adjacent spinal motion segments for imposition of therapy upon three adjacent spinal motion segments, the distal device comprising:

a distal end;

at least one set of threads for engagement with at least one vertebral body; and

a proximal end with a cavity along the centerline of the longitudinal axis of the distal device, the cavity having an engagement zone;

the medial device comprising;

a distal end with an extension adapted to fit at least a portion of the extension within the engagement zone in the cavity of the distal device;

a threaded section for engagement with a vertebral body different from the vertebral body engaged by the distal device;

a proximal end with a cavity along centerline of the longitudinal axis of the medial device containing an engagement zone and a driver engagement section such that rotational force imparted by a corresponding driver head causes the threaded section of the medial device to engage with a vertebral body and advance the medial device towards a previously inserted distal device such that the extension of the medial device enters into the cavity of the distal device and abuts against at least a portion of the surface distal device so that further rotation of the medial device exerts an axial force upon the distal device while rotating relative to the distal device to move the distal device and the at least one engaged vertebral body away from the vertebral body engaged with the medial device; and

the proximal device comprising;

a distal end with an extension adapted to fit at least a portion of the extension within the engagement zone in the cavity of the medial device;

a threaded section for engagement with a vertebral body different than the vertebral body engaged by the distal device and different from the vertebral body engaged by the medial device;

a proximal end with a cavity along centerline of the longitudinal axis of the proximal device containing a driver engagement section such that rotational force imparted by a corresponding driver head causes the threaded section of the proximal device to engage with a the vertebral body and advance the proximal device towards a previously inserted medial device such that the extension of the proximal device enters into the cavity of the medial device and abuts against at least a portion of the surface of the medial device so that further rotation of the proximal device exerts an axial force upon the medial device while rotating relative to the engagement zone to move the medial device and the vertebral body engaged with the medial device away from the vertebral body engaged with the proximal device.

97. The assembly of claim 96 wherein:

the medial device further comprises a thrust bearing such that as the extension of the medial device enters into the cavity of the distal device, the thrust bearing portion of the medial device abuts against the distal device; and

the proximal device further comprises a thrust bearing such that as the extension of the proximal device enters into the cavity of the medial device, the thrust bearing portion of the proximal device abuts against the medial device.

98. A driver for use in creating an assembly inside a patient as accessed through a channel created through a trans-sacral approach to a motion segment in the spinal column, the driver comprising:

a shaft with a distal end and a proximal end;

a driver head on the distal end of the shaft for engagement with a corresponding section on the proximal end of an axially implantable device;

a retention rod within the shaft with a distal end of the retention rod that is threaded, the distal tip of the retention rod extending from the shaft so that it can threadedly engage a corresponding set of threads on the proximal end of the axially implantable device; and

a rotational actuator on the driver to allow selective rotation of the retention rod to selectively engage or disengage from the set of threads on the proximal end of the axially implantable device such that the retention rod can be engaged with the proximal end of the axially implantable device before the axially implantable device and the attached driver are inserted through the channel created through a trans-sacral approach and the retention rod can be disengaged with the proximal end of the axially implantable device after the axially implantable device has been inserted into an assembly accessed through the channel created by the trans-sacral approach.

99. The driver of claim 98 wherein:

the driver has a handle at the proximal end to facilitate rotation of the driver to impart rotation through the driver head to the proximal end of the axially implantable device;

the retention rod extends through the handle and the shaft of the driver to the distal end of the shaft;

the handle is between the distal end of the retention rod and the rotational actuator, the rotational actuator attached to the retention rod and sized to preclude movement of the rotational actuator down through the handle and to the distal end of the shaft so that the retention rod is removed from the driver by moving the distal end of the retention rod through the shaft and out through the handle.

100. The driver of claim 98 wherein the driver head is a male polygonal engagement section to engage with a corresponding female polygonal socket in the proximal end of the axially implantable device and the distal end of the retention rod has a set of male threads for engagement with a corresponding set of female threads in a cavity on the proximal end of the axially implantable device.

101. The driver of claim 98 wherein the driver head is a female polygonal engagement section to engage with the proximal end of the axially implantable device and the distal end of the retention rod has a set of male threads for engagement with a corresponding set of female threads in a cavity on the proximal end of the axially implantable device.

102. A spinal therapy device for deployment in a channel created through a trans-sacral approach, the spinal therapy device comprising:

a distal end;

a proximal end;

a cavity at the proximal end of the device, the cavity located internally along the longitudinal centerline of the device;

a threaded section on the external surface of the device for engaging a vertebral body;

the proximal end of the device having a threaded section on the internal surface for receipt of a corresponding set of threads on a distal end of a disengagement tool so that a disengagement tool can be rotated opposite to the direction for engaging the vertebral body to engage the disengagement tool with the device and after completion of the threaded engagement impart a rotation to the device to disengage the device from the vertebral body such that once disengaged from the vertebral body but still engaged with the disengagement tool, the disengaged device can be removed with the distal end of the disengagement tool from the channel.