An instrument port includes a port body, a bulb disposed at the distal end of the port body, a base body disposed at the proximal end of the port body, a hollow cylindrical body mechanically coupled to the base body, and a plurality of connecting rods disposed parallel to the port body. Each connecting rod includes a distal rod portion that is mechanically coupled to a respective distal-facing exterior surface of a bulb flange and a proximal rod portion that is mechanically coupled to a respective proximal-facing surface of the base body. A spring applies a spring force against the port body to press the port body into the bulb to mechanically secure the bulb to the base body.