Surgical instrument assembly

The surgical instrument of 11 further comprising a guide wire receiving groove formed on an external surface of the hollow sheath body at the front end for receiving a wire therein, and wherein the guide wire receiving groove is positioned to guide the scalpel blade to make the dermatotomy substantially coincident with a puncture surrounding the guide wire.

A method for operating a surgical instrument assembly that includes a surgical instrument, a hollow sheath body and a handle actuator comprising the steps of:

• positioning a hollow sheath body to a first longitudinal position that encapsulates a surgical instrument inside the hollow sheath body;
• placing a front face of the hollow sheath body on a skin surface of a surgical patient while orienting a longitudinal axis of the surgical instrument substantially normal to the skin surface;
• applying a longitudinal force to the handle actuator directed toward the skin surface to thereby position the hollow sheath body to a third longitudinal position to expose the surgical instrument out from the hollow sheath body by a second desired length suitable for making a dermatotomy in a percutaneous procedure.