Patent ID: 7591802

Claim:
A trocar adapted to form a seal around a surgical instrument, comprising: a cannula having an axis extending between a proximal end and a distal end; a housing having a proximal wall and forming with the cannula a working channel sized and configured to receive the instrument; a septum seal disposed in the housing and extending transverse to the axis of the cannula across the working channel, the septum seal having a normal state when the instrument is absent from the working channel and a stretched state when the instrument is being withdrawn from the working channel; portions of the proximal wall of the housing defining an orifice sized and configured to receive the instrument into the working channel; and an elastomeric ring-shaped projection extending axially distally between the proximal wall and the septum seal, the ring-shaped projection having an axial length adapted to deform to prevent inversion and binding of the septum seal and the orifice upon withdrawal of the surgical instrument, wherein the proximal wall comprises a holding feature and wherein the elastomeric ring-shaped projection is fixed and coupled to the holding feature.