A trocar for performing a procedure on a patient. The trocar has a hollow cannula with a distal end and a proximal end. The trocar also has a housing with a distal end attached to the proximal end of the cannula and a proximal end having a wall attached thereto. The wall has an aperture therethrough. The trocar further includes a seal assembly disposed within the housing. The seal assembly includes a first substantially rigid ring, a second substantially rigid ring, and a plurality of layered elastomeric members compressed therebetween. The first ring has a plurality of distally extending protrusions extending from a distal surface thereof, and the second ring has a plurality of proximally extending protrusions extending from a proximal surface thereof.