Most women getting a hysterectomy should keep their ovaries because the common extra step of removing them seems to do no good and might decrease their long-term survival, researchers report. The provocative study, being published Monday in the journal Obstetrics & Gynecology, does not settle the issue. It does not track actual patients, but uses other data to create a model of the surgery’s effects.Still, the work promises to raise questions from women and their doctors about a procedure long accepted despite little evidence to back it.