| 摘要 |
<p>A surgical incising instrument (5) having a helical blade (40) allows a surgeon to helically incise a pathway through tissue into the interior of the body at a controlled rate without exerting longitudinal forces on the instrument. The instrument (5) incorporates a variform or 'split-lands' helix that includes a blade member (40) with a sharp helical blade edge and a shield member (44) with a dull helical edge that mate along helicoidal interfaces that 'split' the lands, thus providing for a helix periphery that may either expose or not expose the sharp blade edge outside the dull lands. The instrument (5) is particularly useful for accessing an anatomic cavity and incorporates a latch and spring mechanism that transforms the variform helix into a dull-edged helix from a sharp-edged helix in response to penetration of a body wall overlying an anatomic cavity, thus protecting organs within the cavity from contact with any sharp blade edge.</p> |
