Abstract: The present invention relates to a dilatation system for a medical device, in particular where the insertion of a tubular structure (e.g. cannula, catheter or drainage tube) is required. The dilatation system is ideally used for tracheostomy procedures, such as Percutaneous Dilating Tracheostomy (PDT). This minimally invasive surgical device enables to open a gap between the first tracheal rings and to introduce a tracheostomy tube in the trachea of a patient. The present invention also relates to a method inserting a tubular structure into a patient for example a tracheostomy tube in the trachea of a patient.