Cannula for a surgical instrument

1. A cannula for a surgical instrument used for cutting selected tissue in a body cavity while under visual inspection, said cannula comprising:

a hollow central lumen extending from its proximal end to its distal end;

said proximal end being open and connectable to a surgical handpiece, allowing passage of an optical system and a cutting tool extension system into said hollow central lumen; and

said distal end being closed;

said cannula has a flat top surface, being circular in cross-section and having a lateral slot in the proximity of said distal end through which a cutting blade can be extended and retracted under operation of the cutting tool extension system while visualizing tissue at said lateral slot with said optical system.

2. The cannula of claim 1 , wherein said cannula is made from a clear material.

3. The cannula of claim 2 , wherein said clear material is polycarbonate.

4. The cannula of claim 1 , wherein said hollow length has a length dimension which ranges from 3 to 15 centimeters.

5. The cannula of claim 1 , wherein the flat top surface has a width and dimension spanning a distance from a first side to a second side of the flat top surface, wherein said width dimension of said flat top surface ranges from .1 to 1.5 centimeters.

6. The cannula of claim 1 , wherein said distal end is turned upwards like an obturator.

7. The cannula of claim 1 , wherein said distal end of the cannula comprises a front edge for separating tissues.

8. A method for performing a uniportal procedure with the cannula of claim 1 for a surgical instrument used for cutting selected tissue in a body cavity while under visual inspection the method comprising the steps of:

a) establishing an entry portal;

b) inserting the distal end of the cannula through the entry portal;

c) advancing the cannula to create a passage to a target tissue;

d) imaging the target tissue with the optical system;

e) performing an endoscopic operation at the target tissue; and

f) withdrawing the cannula from the entry portal.

9. The method of claim 8 , wherein the target tissue is bone or joint.

10. The method of claim 8 , wherein said procedure is a surgical operation comprising the steps of contacting the target tissue with a blade and dividing the target tissue with the blade.

11. The method of claim 9 , wherein said surgical operation is carpal tunnel release and the target tissue is the transverse carpal ligament.

12. The method of claim 9 , wherein said surgical operation is trigger finger release and the target tissue is the A1 pulley.

13. The method of claim 9 , wherein said surgical operation is fascia release.

14. A method for performing uniportal endoscopic carpal tunnel release with the cannula of claim 1 for a surgical instrument used for cutting selected tissue in a body cavity while under visual inspection, the method comprising the steps of:

a) establishing an entry portal proximal or distal of, and proximate to, a transverse carpal ligament;

b) inserting the distal end of the cannula through the entry portal;

c) advancing the cannula to create a passage to and under the transverse carpal ligament;

d) imaging the transverse carpal ligament and tissues surrounding the cannula with the optical system;

e) dividing the transverse carpal ligament; and

f) withdrawing the cannula from the entry portal.