Which procedure involves the removal of a skull flap without subsequent replacement?

A craniectomy involves the surgical removal of a portion of the skull, referred to as a skull flap, without replacing it back in place. This procedure is often performed to relieve pressure on the brain due to conditions such as traumatic brain injury, stroke, or swelling. The absence of replacement allows for continued space for the swelling of brain tissue to occur safely.

In contrast, a craniotomy involves removing a skull flap but is characterized by the intention of replacing it after the intraoperative procedure is completed. Duplex cranioplasty typically refers to reconstructive procedures following craniectomy, where replacement of the skull may occur. Sphenoidal surgery involves approaches to the sphenoid sinus or related structures, which does not involve the same type of skull flap removal as seen with a craniectomy.