By Aubrey Whelan, The Philadelphia Inquirer The Tribune Content Agency

Patients addicted to opioids are arriving at ERs with deep wounds that expose their bones. Some have lost multiple limbs. And many ultimately are leaving hospitals against medical advice, with severe, untreated skin lesions, insisting they can't bear the withdrawal from tranq - the drug that caused their wounds in the first place.

Those were among the stories shared by doctors from Philadelphia's major health systems as they compared notes for the first time on the medical consequences of tranq - the street term for xylazine, an animal tranquilizer that has exploded across the city's illicit opioid supply.

At a weekend symposium hosted at Thomas Jefferson University by Rothman Orthopedics and the Foundation for Opioid Research and Education, physicians outlined the patient cases they'd seen and the limited research on how xylazine affects the body.

"This has really changed the dynamic of the opioid crisis," said Asif Ilyas, an orthopedic surgeon at Rothman who helped organize the event. "And Philadelphia is the front line."

For the last several years, doctors in Philadelphia have been increasingly treating wounds caused by xylazine. Never approved for human use, it is now present in nearly all of the illicit opioids sold in the city. Health officials believe it was initially added to fentanyl to provide a longer-lasting high.

Xylazine also appears to cause severe skin lesions. At Saturday's symposium, doctors said that it's believed the drug is toxic to skin cells and may also constrict blood vessels, slowing the circulation of oxygen in the body and making wounds slower to heal.

Doctors who spoke stressed the importance of collaboration to help patients requiring care that goes beyond simply treating a serious wound.

"Wounds are a symptom of the disease; not the disease itself," said Jason Wink, a plastic surgeon at Penn Medicine.

The risks of leaving treatment early

Doctors working with tranq wounds must also address their patients' addiction: "It is a disease like any other disease," Rachel Haroz, head of Cooper University Hospital's toxicology and addiction medicine division, told her colleagues from other specialties.

Of particular concern are patients with wounds who leave against medical advice before their treatment is complete. Sometimes, that's because doctors haven't adequately treated their withdrawal symptoms.

Avoiding wound treatment can have serious consequences. Katherine Woozley, the head of Cooper's orthopedic hand and nerve surgery division, spoke about a man who had arrived at Cooper with a wound that covered much of his forearm, and a host of other medical issues, including endocarditis, an infection of the heart valves often seen among people who inject their drugs.

The man ultimately left the hospital against medical advice, only to come back a year later with his arm missing below his shoulder, and a section of bone exposed. He told doctors the arm had fallen off on its own about six months before.

Woozley didn't say why that man had originally left the hospital, but stressed that surgeons treating tranq wounds must work closely with addiction specialists and other social support services to give patients a better shot at healing.

'People are trying'

At Temple University Hospital, doctors are seeing success with synthetic skin coverings that can protect a wound for up to a year, allowing it to heal even if a patient isn't ready to quit using drugs. Lisa Rae, Temple's chief of burn surgery, said her goal is to decrease patients' risk of amputation.

She spoke of a patient with a wound that had exposed the joints in their wrist, who kept leaving the hospital and was continuing to inject drugs. Doctors covered the wound with synthetic skin and, earlier this year, the person entered recovery. At a recent follow-up, the wound was almost healed, Rae said.

"Don't give up on wound care," Rae said. "People are trying. This gives them time to find their way out."

Other surgeons spoke about navigating treatment for patients with wounds so severe they can no longer use their limb.

Wink, the Penn plastic surgeon, recalled a woman who had not used drugs for three months, but still dealt with a serious wound on her forearm. She told doctors she wanted to save the limb, but ultimately felt relief when it had to be amputated.

"Amputation can remove the burden of wounds from a patient," Wink said, urging careful consultations with patients, their families and other doctors before proceeding with a life-changing surgery.

Developing guidelines for care

Doctors at Saturday's symposium said they're beginning to develop comprehensive recommendations for classifying and treating tranq wounds. Earlier this year, Philadelphia health officials also released guidelines on wound treatment.

And addiction medicine experts stressed that hospitals must also emphasize follow-up care for patients who use xylazine, ensuring that patients have adequate medication, wound-care supplies, and connections to social services when they leave the hospital.

Ilyas said he was pleased that the first-of-its-kind symposium had brought together so many doctors with different perspectives and areas of expertise. "This is not a problem managed by just surgery," he said.

In the early days of the crisis, he said, "we weren't managing the problem in front of us, which is fundamentally addiction. And this type of wound crosses multiple surgical specialties - orthopedic, burn, plastic, general. Most of us have never trained on these injuries, so it's important to exchange notes."