In this task, you're given a sentence and your task is to generate a simplified sentence that focuses on lexical paraphrasing from the original sentence given in the input.

obsidian has been used in cardiac surgery , as well-crafted obsidian blades have a cutting edge many times sharper than high-quality steel surgical scalpels , with the edge of the blade being only about 3 nanometres wide.
obsidian has been used in heart surgery , as well-crafted obsidian blades have a cutting edge many times sharper than high-quality steel surgical scalpels , with the edge of the blade being only about 3 nanometres wide.