Active cannulas

Abstract

An active cannula which does more than merely maintain a passage is usable to create and / or enlarge a passage, to position a scope or instrument, to move or locate tissue, etc. The cannula can vary in size or shape as needed, intraoperatively. Because a cannula of the present invention is expandable, the surgeon can make a relatively small incision, stretch the tissue with the expandable cannula, contract the cannula and remove it, allowing the skin to come back to its unstretched condition. Thus, a smaller incision can be made to fit the same size instrument. The cannulas can assume such a non-circular shape, to fit into a natural skin opening and cause less trauma. The devices can be used to seal off a space, expand an existing space or a potential space for working or visualization, move tissue (for example, to stretch an incision), or protect tissue.

Description

RELATED APPLICATIONS [0001] This application is a continuation of co-pending U.S. application Ser. No. 10 / 099,265 filed Mar. 14, 2002 which is a continuation of U.S. application Ser. No. 08 / 727,968 filed on Oct. 9, 1996, now U.S. Pat. No. 6,358,266, which is a divisional of U.S. application Ser. No. 08 / 462,420, filed on Jun. 5, 1995, now U.S. Pat. No. 6,171,299, which is a divisional of U.S. application Ser. No. 08 / 195,337, filed on Feb. 14, 1994, now U.S. Pat. No. 5,514,153, which is a continuation-in-part of U.S. application Ser. No. 07 / 792,730, filed on Nov. 15, 1991, now U.S. Pat. No. 5,295,994, and a continuation-in-part of U.S. application Ser. No. 08 / 054,416, filed on Apr. 28, 1993, now abandoned, which is a divisional of U.S. application Ser. No. 07 / 487,645 filed on Mar. 2, 1990, now U.S. Pat. No. 5,331,975. The benefit of the earlier filing date of aforementioned applications is hereby claimed. The specifications of the aforementioned applications are hereby fully and expre...

AI Technical Summary

Benefits of technology

Enables safer and more effective surgical procedures by allowing for smaller skin incisions, reducing tissue trauma, and improving visualization and access within the body without causing necrosis or excessive swelling.

Problems solved by technology

They cannot be varied intraoperatively in length and width to accommodate larger devices or varying size devices through the skin.

Problems with the water method include fluid extravasation including into and through the tissue itself.

Increased pressure and swelling result in the area, resulting in edematous or swollen tissue.

Excess pressure from mechanical refractors may cause necrosis or tissue death.

With these methods, it is impossible to monitor the pressure being applied to the body tissues, and tissue damage or necrosis can result.

While operating from within the body, i.e., fiber optic assisted surgery as opposed to open surgery, there is no known way to selectively move or retract tissue, either hard tissue such as bone or soft tissue, out of the way to improve visualization.

No device in use adequately allows a surgeon to create an actual space or expand a potential space in the body, by separating adjacent layers of tissue.

The prior art does not disclose a retractor which is powerful enough and made of a material which is strong and resilient enough to, for example, separate tissue planes from within.

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