Trocar seal with retraction induced hinge

1. An instrument seal for use in a trocar with an alignment channel, the instrument seal comprising a mounting seal, a base portion extending medially and distally from the mounting seal, and a bending portion extending medially from the base portion, the bending portion and base portion being spaced relative to the alignment channel such that when a surgical instrument is retracted the bending portion inverts and does not enter the alignment channel; wherein the base portion has a thickness greater than a thickness of the bending portion.

2. The instrument seal of claim 1 , wherein the base portion and bending portion have respective wall thicknesses with a ratio between about 1.5:1 and about 4:1.

3. The instrument seal of claim 1 , wherein the bending portion has a generally frusto-conical geometry.

4. The instrument seal of claim 3 , wherein the base portion has a generally cylindrical geometry.

5. The instrument seal of claim 1 , wherein the bending portion further comprises a lip defining an opening.

6. The instrument seal of claim 1 , further comprising a hinge area adjacent the base and bending portions.

7. The instrument seal of claim 1 , wherein the mounting seal is annular.

8. A instrument seal for use in a trocar having a cannula with a distal end, a housing with a proximal end, and an alignment channel aligned with the cannula and positioned distally relative to the housing proximal end, the alignment channel having a length and an inside diameter, the length being greater than the inside diameter, the instrument seal comprising:

a lip defining an opening adapted to be aligned with the alignment channel and positioned distally relative to the alignment channel, a bending portion extending laterally and proximally from the lip, a base portion, a hinge area adjacent the base and bending portions, and a mounting seal positioned laterally from the base portion, wherein the base and bending portions have respective wall thicknesses and the base portion is thicker than the bending portion;

wherein the bending and base portions are adapted to be spaced distally from the alignment channel such that when a surgical instrument is refracted the bending portion inverts and the lip does not enter the alignment channel.

9. The instrument seal of claim 8 , wherein the thickness ratio of the base portion and bending portion is between about 2:1 and about 3:1.

10. The instrument seal of claim 8 , wherein the base portion is adapted to abut the alignment channel.

11. An instrument seal for use in a trocar having a cannula and an alignment channel aligned with the cannula, the alignment channel having a length and an inside diameter, the length being greater than the inside diameter, the instrument seal comprising an opening adapted to be aligned with the alignment channel and positioned distally relative to the alignment channel, a bending portion extending laterally and proximally from the opening, a base portion connected to the bending portion, the base portion being thicker than the bending portion, and a mounting seal positioned laterally from the base portion.