This invention generally relates to a medical device assembly for facilitating a sealed working channel into a pressurized body cavity, and methods of use thereof. In certain embodiments, devices of the invention include a hollow body that is splittable along its length and being configured to move between an open configuration for operably coupling with a surgical instrument and a closed configuration, in which in the closed configuration, the device provides a seal that prevents gas leakage from an incision site of a body cavity while the instrument is in the body cavity.