What is a surgical conversion?

Hi ladies,

Someone made this recommendation to me when asking advice for finding a good hysterectomy surgeon. "I suggest that you ask your prospective surgeons directly about their rates of complications or surgical conversions.”
Does anyone know what this means? Any advice is welcome!

Thanks!

that means how many surgeries does the dr do (like vaginal, tlh, lsh) that have to be converted to abdominal surgery.

Ahhhh...thank you!