Hi and thanks for your question. In rhinoplasty thermoplastic cast is used for stability of the nasal bone. During the rhinoplasty, osteotomy is done for 2 aim; After removing the nasal hump , open roof is created on the nose, so this open roof is closed with osteotomy( cutting the nasal bone with ultrasonic device)If the bony base of the nose is too wide , it is decreased with osteotomy. If during the rhinoplasty, osteotomy is done , thermoplastic cast is used for stability of the nasal bone and this cast is removed 7-10 days after the surgery. If rhinoplasty contains only tip plasty, cast may not be used ,because there is no need for nasal bone stability.