Bianca Kennedy's hot flashes were so insufferable that she was willing to risk a host of complications, including infection and seizures, to have a long hypodermic needle plunged into her neck.The procedure, called a stellate ganglion block, is normally used to alleviate severe pain caused by overactivity of the sympathetic nervous system. But since last year, a northwest suburban doctor has been offering it to women for relief of menopause symptoms. Experts say putting the technique to this use is risky and untested--one researcher called it "a crock." But Kennedy says it is the only remedy that has ever worked for her."I would have 20 to 25 hot flashes a day," said Kennedy, 39, who was thrown into premature menopause following breast cancer. "Once, when I was visiting family in Texas, I had to move to a hotel because I couldn't get the air conditioning cold enough. It was just brutal. . . . I felt like I was going to explode, and this is the only thing that has actually helped."