Every year more than half a million American kids have drainage(排泄) tubes surgically implanted in their ears to combat persistent infections. The procedure, known as tympanostomy, may not be as 【C1】______ as the tonsillectomy was in the 1940s, but it now 【C2】______ as the nation's leading childhood 【C3】______ and a new study suggests it's being vastly overused. In 【C4】______ more than 6,000 scheduled ear tube operations, a team of experts 【C5】______ by Harvard pediatrician Lawrence Kleinman found that fewer than half were clearly justified. "Each year", the researchers write in the current Journal of the American Medical Association (JAMA), "several hundred thousand children in the United States may be 【C6】______ tympanostomy tubes that offer them no demonstrated 【C7】______ ...and may place them at increased 【C8】______ ."
Tube placement isn't a 【C9】______ risky procedure, but it costs $1,000 to $1,500 and sometimes scars the eardrum, causing a partial loss of 【C10】______ Studies show that the benefits are most likely to 【C11】______ the risks if a child's middle ear has produced sticky fluid 【C12】______ more than four months despite treatment 【C13】______ antibiotics. For less virulent infections, drug treatment is usually a(n) 【C14】______ safer alternative (though drugs, too, can be overused). In the new JAMA study, Kleinman's team reviewed the medical charts of 6,429 kids, all under 16, 【C15】______ doctors had recommended the procedure. Even making "generous assumptions" about the likely 【C16】______ , the researchers found that a quarter of the proposed operations were 【C17】______ , since less invasive alternatives were available, 【C18】______ another third were as likely to harm the recipients as help them.
Parents needn't 【C19】______ about ear tubes that are already in place. Once 【C20】______ implanted, the tiny devices provide drainage for six months to a year, then come out by reducing health costs by hundreds of millions of dollars every year.
【C1】

A. rare
B. common
C. general
D. abnormal