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Children with hearing loss who get ear-tube surgery to address chronic ear infections may need tests to see whether their hearing improves, a study suggests.

When kids get an infection, fluid can build up in the middle ear, making it difficult for them to hear and potentially impairing speech and language development, said lead study author Kenneth R. Whittemore Jr., a researcher at Boston Children’s Hospital.

“Completion of a hearing test after ear tubes are placed is important for a child who had hearing loss before the tubes,” Whittemore said by email. “While the majority of the hearing losses resolve, there will be some patients who have previously unknown permanent hearing loss that will be present even after the placement of ear tubes.”

Ear-tube surgery is the most common operation performed on children, with roughly 667,000 American kids getting this procedure every year, Whittemore and colleagues note in JAMA Otolaryngology — Head and Neck Surgery.

Their study examined data on 2,274 patients who received ear tubes in 2010 and 2011. On average, patients were about 2.6 years old, although people up to age 24 were included.

Roughly 77 percent of kids had hearing tests before the surgery. About two-thirds had tests both before and after. Roughly 8 percent didn’t get any hearing evaluations at all.

After surgery, about 20 percent of the patients who had preoperative evaluations had hearing loss. In no case, however, did anyone with a normal preoperative hearing test have postoperative hearing loss, the authors reported. Within a year of surgery, 271 patients, or about 12 percent, had evidence of nonfunctional ear tubes, the study found.

Roughly 4 percent of the kids turned out to have hearing loss that might have been missed without tests after surgery, the study also found. That’s because they had some hearing loss unrelated to ear infections.

The findings suggest that postoperative hearing tests make sense for children who had problems before surgery, the authors conclude. Kids who didn’t have hearing issues prior to surgery, however, might not need hearing tests afterwards.

The most common reason for persistent hearing loss after surgery is malfunctioning ear tubes, which can happen if the tubes come out prematurely or if wax or mucus or some other substance clogs them and makes them ineffective at helping fluid drain from the ear.