After Pittsburgh Steelers outside linebacker T.J. Watt needed emergency surgery for a partially collapsed lung following a “dry needling” treatment this week, many sports fans are asking, “What is dry needling, and how could it result in such a serious complication?”

The freak injury suffered at the Steelers’ practice facility, according to his brother J.J. Watt, will keep Watt out of the lineup Monday night against the Miami Dolphins. What happens after that is unclear.

TribLive reached out to health care experts to learn more about this treatment.

How does dry needling work?

Amy Green, an acupuncturist and clinical director at Heal PGH, said practitioners have used forms of dry needling to treat pain for thousands of years. She said the technique targets specific problem areas that can trigger or contribute to widespread pain throughout the body.

Manning Physical Therapy & Sports Medicine in Green Tree describes dry needling as the “insertion and repetitive manipulation of a ‘dry,’ solid filament needle in a trigger point,” according to its website.

During the procedure, the needle penetrates the body’s myofascial tissue — the connective tissue that runs throughout the body. This tissue is highly sensitive, Green said, and can become painful when it tightens or “knots.”

“What happens is it (the needle) creates a reflex arc to the spine, which creates a twitch in the muscle. It helps to reset muscle length and alleviate referred pain from a trigger point,” Green said.

Dry needling can be used to address a wide range of physical pain, including migraines, lower back and neck pain, plantar fasciitis, tendinitis and post-traumatic injuries like those resulting from car accidents.

Is dry needling dangerous?

While commonly practiced in the sports world, dry needling is not legal in all 50 states.

The American Physical Therapy Association notes that dry needling is illegal in California, Hawaii, New York, Oregon and Washington. In other states, including Connecticut, Massachusetts, Michigan, Minnesota, Missouri, Oklahoma and Pennsylvania, there are no clear laws either permitting or banning physical therapists from performing the procedure.

“I’m actually scared of dry needling,” Steelers linebacker Patrick Queen told reporters Friday. “I stay away from that stuff. It’s unfortunate. You can probably get dry needled a thousand times and not have anything happen. Half inch in the wrong direction, you never know. It’s definitely unfortunate.”

Green, who described herself as deeply passionate about the benefits of dry needling, emphasized practitioners must have an “exquisite sense of their fingers to navigate the anatomy,” warning that, without it, the risks can be severe.

What may have happened to Watt?

Dr. Ryan Chiu, a cardiothoracic surgeon at Memorial Care Long Beach Medical Center in California, explained, if a needle goes too deep and enters the pleural cavity, it can injure the lung or let air in, potentially leading to lung compression or collapse. The pleural cavity is the fluid-filled space between the two layers of the pleura, the membrane that encases each lung.

Green added the length of the needles varies depending on the area being treated.

On a thinner patient, Chiu said, the needle might only need to be a few inches long to be able to puncture a human lung.

“An NFL player who’s more muscular … it would require (a needle) probably longer than that, maybe anywhere from four to five inches to enter the cavity,” Chiu said.

According to Chiu, recovery time is fairly quick following the surgery.

“Patients are able to leave the hospital anywhere from 24 to 72 hours afterward, barring any complications, and then they’re usually able to return back to normal activity within a few weeks,” he said.

While Chiu wasn’t certain playing professional football counts as “normal activity,” he suggested, if Watt underwent minimally invasive surgery, a return to full function within a few weeks could be possible.

Staff writer Joe Rutter contributed to this report.