An instrument access device of a teleoperated surgical system includes an envelope, a clamp, and a plurality of ports. The envelope includes a distal opening and a cavity. The clamp is in the distal opening of the envelope. The plurality of ports are coupled to the envelope. The plurality of ports are proximal to the clamp and the distal opening of the envelope. Each of the plurality of ports includes a seal, which is sized and shaped to seal an outer surface of a cannula and to fix a position of the cannula relative to the port and the envelope.