The warnings against driving while using a cell phone have been around nearly as long as the devices themselves. But since phones morphed into “smart" handheld computers a decade ago, the driver’s seat is not the only place they have led to injury.

Hey, you! Walking down the sidewalk, texting your buddy, liking that Instagram dog photo, watching a Star Wars trailer. Researchers at Rutgers New Jersey Medical School have crunched the numbers, and it seems you need to watch where you’re going.

Data from a national sample of emergency room visits suggest that thousands of head and neck injuries result each year from cell-phone use, and a substantial portion of them occur while walking, the researchers reported in a study Thursday.

The rate of such injuries has climbed sharply since the introduction of smartphones a decade ago, the authors wrote in JAMA Otolaryngology-Head and Neck Surgery.

“That’s when our phones became not-phones,” said senior author Boris Paskhover, an assistant professor at the medical school. “We don’t use our phones to make calls anymore.”

Using emergency-room data gathered from 100 hospitals by the U.S. Consumer Product Safety Commission, the authors identified 2,501 patients who suffered head or neck injuries as a result of cell phone use between January 1998 and December 2017.

Extrapolating from that sample, the researchers estimated that at least 76,000 such injuries had occurred nationwide during the 20-year period — with more than 9,000 cases a year in 2016 and 2017, the most recent years available.

The exact proportion of injuries suffered by pedestrians vs. motorists was unclear, as the details provided to emergency room personnel were sometimes incomplete. A patient involved in a car accident may conceal the fact that he was using a cell phone in order to minimize liability, said Paskhover, division chief of facial plastics and reconstructive surgery at St. Barnabas Medical Center in Livingston, N.J.

Others may omit details of cell-phone use out of embarrassment or, in the event of grave injury, because they are incapacitated, he said.

“The numbers here are super-underreported,” Paskhover said.

The analysis also did not include visits to urgent care centers or other health-care providers.

In 31,000 of the estimated 76,000 cases, the accident occurred at home, suggesting a car was not involved. An estimated 13,000 cases occurred on a roadway. Other reported sites included industrial properties and farms, but no location was recorded in one-third of cases.

People engaged with their cell phones wait to cross Broad Street at Market Street during the evening rush hour in Center City on Dec. 4.
ELIZABETH ROBERTSON / Staff Photographer
People engaged with their cell phones wait to cross Broad Street at Market Street during the evening rush hour in Center City on Dec. 4.

Lacerations and contusions were the most common complaints, though sprains, fractures, and concussions also made the list. For 94% of the injuries, the patient was treated in the emergency room, or released without any treatment.

In addition to accidents for which phone use was associated with the injury, typically because the user was distracted, the authors also identified cases in which the phone caused a direct injury, such as by hitting the person’s face.

Nearly 40% of all injuries were suffered by patients ages 13 to 29, the most of any age group.

That squares with a 2013 University of Maryland study, which looked at phone-related injuries in all body parts, not just the head and neck. Authors of that research found that 54% of injuries occurred in cell-phone users who were 40 or younger.

The risk of walking without watching for obstacles may seem obvious. “We’re not paying attention to our surroundings, and then we get injured," Paskhover said.

But given the magnetic appeal of these ubiquitous devices, he and his Rutgers colleagues said some sort of education campaign is warranted.