You would never have known it from her performance at the Grammy Awards ceremony on Sunday night, but the British singer Adele was not even allowed to speak for most of November and December. She had just undergone laser surgery to remove a polyp from her vocal folds, a small growth that forced her to cancel a U.S. tour and threatened to damage her sultry voice permanently. It was an extreme form of an injury that anyone can get simply by yelling too much.

The problems began last May, Adele wrote in her blog: “I made a Skype call in the morning on the day of the show and during it my voice suddenly switched off like a light! It was literally as if someone pulled a curtain over my throat.” At a show soon afterward, Adele described feeling a “ripping” sensation in her throat, which her doctors diagnosed as a hemorrhage. They ordered her to rest her voice and reschedule several performances.

A vocal cord hemorrhage such as Adele’s happens because of the physical stresses of singing or speaking. When Adele first began noticing problems with her voice, she said she had never sung so much in her life. When vocal cords are overworked or injured, they can bruise just like other body parts—in the larynx, blood escapes the tiny blood vessels and floods the vibrating flaps that allow a person to talk or sing. The bleeding and subsequent swelling can stiffen the vocal cords and interfere with their undulations, leading to hoarseness, or in some cases (such as Adele’s) the inability to speak at all. Many people experience minor vocal cord damage after yelling at a sporting event or noisy bar. In most cases, these can be treated by simply resting the voice.

Adele’s throat problems resumed in October, prompting her doctors to take a closer look. They discovered the polyp, which was possibly caused by previous damage that hadn’t healed properly and which may have been aggravated by the singer’s cigarette smoking.

Because polyps can predispose a singer to repeated hemorrhaging, leading to vocal cord scarring and permanent hoarseness of the voice, laryngeal surgeon Steven Zeitels from Massachusetts General Hospital decided to remove the polyp in November. To do so, he used a laser to snip it off and cauterize the ruptured blood vessels—an hour-long procedure that Zeitels has also performed on Aerosmith’s Steven Tyler, Roger Daltrey from the Who and several other professional singers.

Adele’s performance last night was her first since October. Judging from the standing ovation she received (not to mention the six Grammys she took home), the operation was a success.