Methods for endometrial ablation
A method for ablating a uterine endometrium enlarges an expandable-contractible frame to expand a compliant energy-delivery surface into a planar triangular shape and engage the surface against the walls of a patient's uterine cavity. The frame has flexible outer elements in lateral contact with the compliant surface and flexible inner elements not in said lateral contact, wherein the inner flexible element and outer flexible elements have substantially dissimilar material properties. Energy is applied through the compliant energy-delivery surface to ablate the endometrium.
1. A method for endometrial ablation comprising:
expanding a frame within a compliant energy-delivery surface to cause the surface to assume a planar triangular shape having distal apices to engage the walls of a patient's uterine cavity;
wherein the frame has flexible outer elements in lateral contact with the compliant surface and flexible inner elements not in said lateral contact, wherein the flexible inner elements and the outer flexible elements have substantially dissimilar material properties to cause lateral sides of the frame to become relatively linear and less bowed inward.
2. The method of claim 1 , wherein the compliant energy-delivery surface is configured for primary expansion in a lateral direction by the frame wherein axial movement of the flexible inner elements moves portions of the flexible outer elements laterally.
3. The method of claim 1 , wherein the flexible inner elements have a higher spring constant than the outer flexible elements.
4. The method of claim 1 , wherein the flexible inner elements have a plastic deformation range greater than the flexible outer elements.
5. The method of claim 1 , wherein the flexible inner elements are configured to maintain their spring function at operating temperatures.
6. The method of claim 1 , wherein the flexible inner elements are formed from a precipitation hardenable stainless steel.
7. The method of claim 1 , wherein the flexible outer elements are 304 SS or 316 SS.
8. The method of claim 1 , wherein the flexible inner elements have a thickness greater than 0.012″.
9. The method of claim 1 , wherein the flexible outer elements have a thickness less than 0.012″.
10. The method of claim 1 , wherein the flexible inner elements have a thickness ranging between 0.0012″ and 0.020″.
11. The method of claim 1 , wherein the flexible outer elements have a thickness ranging between 0.004″ and 0.012″.
12. The method of claim 1 , wherein outer and inner elements of the frame are fixed to one another at an apex and a dielectric material overlies said apex.
13. The method of claim 12 , wherein said dielectric material has a thickness in the range from 0.005″ to 0.025″.
14. A method for endometrial ablation comprising:
introducing a collapsed, compliant energy-delivery surface and frame transcervically into a patient's uterine cavity;
expanding the frame within the compliant energy-delivery surface to cause the surface to assume a planar triangular shape to engage the walls of a patient's uterine cavity, wherein the frame comprises flexible inner elements and outer flexible elements which have substantially dissimilar material properties to cause lateral sides of the frame to become relatively linear and less bowed inward;
wherein said compliant energy-delivery surface when in the planar triangular shape includes axial lengths ranging between 4.5 cm and 6.5 cm; and
delivering energy from the energy-delivery surface to ablate tissue.
15. The method of claim 14 , wherein the planar triangular shape has a width between a first apex and second apex ranging between 2.5 cm and 5 cm.
16. The method of claim 14 , wherein the compliant surface is configured for primary expansion laterally outward from the axis by the frame.
17. The method of claim 14 , wherein the compliant surface has a surface area of at least 25 cm 2 .
18. The method of claim 14 , wherein the compliant surface has a surface area ranging at least between 25 cm 2 and 30 cm 2 .
19. The method of claim 14 , wherein the compliant surface has a surface area of at least 22 cm 2 when the selected length is 4.0 cm.
20. The method of claim 14 , wherein the compliant surface has a surface area of at least 23 cm 2 when the selected length is 4.5 cm.
21. The method of claim 14 , wherein the compliant surface has a surface area of at least 24 cm 2 when the selected length is 5.0 cm.
22. The method of claim 14 , wherein outer and inner elements of the frame are fixed to one another at an apex and a dielectric material overlies said apex.
23. The method of claim 22 , wherein said dielectric material has a thickness in the range from 0.005″ to 0.025″.