Dilation system and method

1. A dilation system, comprising:

a dilator assembly comprising a plurality of dilator segments, each dilator segment having a proximal end, a distal end, an inner side, and an outer side, the inner side of each of the dilator segments having a proximal tapered surface extending from the proximal end toward the distal end and a distal tapered surface extending from the distal end toward the proximal end; and

an actuating mechanism having an upper wedge and a lower wedge axially moveable relative to one another, the upper wedge having a tapered surface corresponding to the proximal tapered surface of the dilator segments such that the tapered surface of the upper wedge is slidable along the proximal tapered surface of the dilator segments and the lower wedge having a tapered surface corresponding to the distal tapered surface of the dilator segments such that the tapered surface of the lower wedge is slidable along the distal tapered surface of the dilator segments, the upper wedge and the lower wedge being axially moveable relative to one another in a way to cause the dilator segments to move between a collapsed state and an expanded state,

wherein the actuating mechanism further includes an actuating handle comprising:

a first handle; and

a second handle pivotally connected to the first handle and configured in such a way that movement of the first handle and the second handle relative to one another causes translational movement of the upper wedge relative to the lower wedge.

2. The dilation system of claim 1 , wherein the actuating mechanism further comprises a rod extending from the lower wedge and being pivotally connected to the first handle.

3. The dilation system of claim 2 , the upper wedge is slidably received over the rod.

4. The dilation system of claim 3 , wherein the upper wedge is rotatably connected to the second handle of the actuating mechanism in a way that rotation of the upper wedge rotates the dilator assembly.

5. The dilation system of claim 1 , wherein the actuating handle includes an incremental indicator for identifying the diameter of the dilator assembly.

6. The dilation system of claim 1 wherein the actuating handle includes a ratchet having at least two teeth forming a groove, and a finger capable of being slidably received within the groove.

7. The dilation system of claim 1 , wherein the dilator segments are biased in the collapsed state.

8. The dilation system of claim 1 , wherein at least one of the dilator segments has a slot formed in the outer surface thereof for receiving a probe.

9. The dilation system of claim 1 , wherein the upper wedge is rotatably connected to the second handle of the actuating mechanism in a way that rotation of the upper wedge rotates the dilator assembly.

10. A dilation system, comprising:

a dilator assembly comprising a plurality of dilator segments, each dilator segment having a proximal end, a distal end, an inner side, and an outer side, the inner side of each of the dilator segments having a proximal tapered surface extending from the proximal end toward the distal end and a distal tapered surface extending from the distal end toward the proximal end; and

an actuating mechanism having an upper wedge and a lower wedge axially moveable relative to one another, the upper wedge having a tapered surface corresponding to the proximal tapered surface of the dilator segments such that the tapered surface of the upper wedge is slidable along the proximal tapered surface of the dilator segments and the lower wedge having a tapered surface corresponding to the distal tapered surface of the dilator segments such that the tapered surface of the lower wedge is slidable along the distal tapered surface of the dilator segments, the upper wedge and the lower wedge being axially moveable relative to one another in a way to cause the dilator segments to move between a collapsed state and an expanded state,

wherein at least one of the dilator segments includes an electrode assembly.

11. The dilation system of claim 10 , wherein the dilator segments are biased in the collapsed state.

12. The dilation system of claim 10 , wherein at least one of the dilator segments has a slot formed in the outer surface thereof for receiving a probe.

13. The dilation system of claim 10 , wherein the upper wedge is rotatably connected to the second handle of the actuating mechanism in a way that rotation of the upper wedge rotates the dilator assembly.

14. A method of forming an access opening through a psoas muscle to a patient's spine, comprising the steps of:

inserting a guide into the psoas muscle to locate a safe zone in the psoas muscle;

laterally inserting a guide through the psoas muscle such that a guide tip is proximate the patient's spine;

inserting a dilator assembly through the psoas muscle and toward the patient's spine guided by sliding engagement of the probe, the dilator assembly comprising a plurality of dilator segments; and

expanding the dilator segments radially from a collapsed state to an expanded state,

wherein the step of expanding the dilator segments comprises applying an axial compressive force to the dilator segments,

wherein the step of applying an axial compressive force further comprises:

moving an upper wedge and a lower wedge relative to one another to cause a tapered surface of the upper wedge to slidably move along a corresponding tapered surface at the proximal end of the dilator segments and a tapered surface of the lower wedge to slidably move along a corresponding surface at the distal end of the dilator segments.

15. The method of claim 14 , wherein the guide is a stimulating probe, and wherein the method further comprises inserting the stimulating probe into the psoas muscle to locate a safe zone in the psoas muscle prior to inserting the dilator assembly through the psoas muscle.

16. A method of forming an access opening through a psoas muscle to a patient's spine, comprising the steps of:

inserting a guide into the psoas muscle to locate a safe zone in the psoas muscle;

laterally inserting a guide through the psoas muscle such that a guide tip is proximate the patient's spine;

inserting a dilator assembly through the psoas muscle and toward the patient's spine guided by sliding engagement of the probe, the dilator assembly comprising a plurality of dilator segments; and

expanding the dilator segments radially from a collapsed state to an expanded state,

wherein at least one of the dilator segments includes an electrode assembly, and wherein the method further comprises the steps of:

incrementally expanding the dilator assembly; and

rotating the dilator assembly to verify the safe zone in the psoas muscle prior to each incremental expansion.

17. The method of claim 16 , wherein the guide is a stimulating probe, and wherein the method further comprises inserting the stimulating probe into the psoas muscle to locate a safe zone in the psoas muscle prior to inserting the dilator assembly through the psoas muscle.