单项选择题

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 (67) as the tonsillectomy was in the 1940s, but it now (68) as the nation’s leading childhood (69) and a new study suggests it’s being vastly overused. In (70) more than 6,000 scheduled ear tube operations, a team of experts (71) 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 (72) tympanostomy tubes that offer them no demonstrated (73) ...and may place them at increased (74) ."
Tube placement isn’t a (75) risky procedure, but it costs $1,000 to $t,500 and sometimes scars the eardrum, causing a partial loss of (76) . Studies show.that the benefits are most likely to (77) the risks ifa child’s middle ear has produced sticky fluid (78) more than four months despite treatment (79) antibiotics. For less virulent infections, drug treatment is usually a(n) (80) , 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, (81) doctors had recommended the procedure. Even making "generous assumptions" about the likely (82) , the researchers found that a quarter of the proposed operations were (83) , since less invasive alternatives were available, (84) another third were as likely to harm the recipients as help them.
Parents needn’t (85) about ear tubes that are already in place. Once (86) 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