What to know about Phillies prospect Aidan Miller’s spinal procedure

Phillies top prospect Aidan Miller’s 2026 season may be riding on a spinal procedure for lower back pain set for Friday.

The outpatient procedure, called radiofrequency ablation of the facet joints, involves zapping nerves that relay pain to the brain.

The treatment won’t fix the underlying problem, but could temporarily relieve pain, so the infielder can rehabilitate.

Miller, who turns 22 next week, was diagnosed with discogenic pain and facet inflammation in the lumbar spine, according to the Phillies.

The Inquirer spoke to spine experts at Temple University Hospital and Drexel University College of Medicine about his diagnoses, the spinal procedure, and what recovery will look like. Here’s what to know:

Discogenic pain refers to pain stemming from the discs — the flat, round cushions that sit between the bones in the spine.

Think of them as jelly donuts. The outer part of the donut is thick and fibrous, while the inner part is jelly-like, explained Philip Koehler, a physical medicine and rehabilitation doctor at Rothman Orthopaedics and Drexel.

“Through injury, such as bending, lifting, twisting, or aging, that outer part can crack and tear, and that is actually very painful,” said Koehler, who is not Miller’s doctor.

Treatment differs based on the severity of the injury. Severe leg pain and weakness can call for surgery. If they have mild leg pain, treatment could include epidural injections.

And when the issue is back pain with no leg pain at all, “there’s not a lot of things that have been shown to be very effective,” Koehler said.

Physical therapy and rehabilitation and medication management would be standard care in that scenario.

The second part of Miller’s diagnosis, facet inflammation, happens when joints in the back of the spine become inflamed and painful.

Rotating and bending backwards would trigger pain in the facet joints, while forward bending, twisting, and lifting, would typically set off pain in the disc, Koehler said.

Miller’s diagnosis reflects the physical challenges of playing shortstop.

“There’s a lot of explosive motion going side-to-side for this patient,” said Theresa Pazionis, a spinal surgeon at Temple University Hospital, who is also not his doctor.

Facet inflammation and discogenic pain are often seen together.

Picture a tripod-like structure: for each disc up and down the spine, there are two facet joints on either side to stabilize the spine. An issue with the discs can create instability in the spine, which can lead to problems for the facets.

Miller’s procedure only addresses pain from the facet joints, rather than the discs.

The minimally-invasive procedure involves inserting a needle into the spine.

An X-ray camera then guides the needle to the medial branch nerve, whose job is to tell the brain about sensation coming from the facet joint.

The doctor burns the nerve, “so your brain doesn’t know that the joint is in pain,” Koehler said.

The nonsurgical procedure is low-risk, with limited complications, such as soreness at the injection site, he said.

If done improperly, there’s a “one-in-a-million chance” of injuring a nerve that gives power to the leg, he added.

The procedure usually takes effect after three to six weeks.

The Phillies’ timeline has Miller resuming playing in six to eight weeks. President of baseball operations Dave Dombrowski said the “best-case scenario” would see Miller playing in the minor leagues by August and then going to the Arizona Fall League.

“It’s supposed to fix the issue,” Dombrowski said. “So, we’ll wait and we’ll see.”

» READ MORE: Phillies top prospect Aidan Miller to have spinal procedure; might still play this season

The procedure is commonly used to treat pain caused by arthritis, although it is unknown whether that is the cause of Miller’s pain.

It is not typically used in young people, however, a high-level athlete is more likely to have arthritis due to physical activity and prior injuries, Koehler said.

The treatment can also help with inflammation and facet injury from stretching, Pazionis said.

She emphasized that the procedure does not fix the underlying problem driving the pain. It merely provides enough relief for a patient to engage in rehabilitation and core-strengthening exercises.

Just because he’s out of pain wouldn’t mean he can go back to aggressive sports, she cautioned.

“If they don’t take time to rehab appropriately, they may never heal that injury, and it could get worse in the long run,” she said.

It is also not considered a permanent fix. Eventually the nerves will grow back. How long that takes can range, typically from several months to two years.

“If it is successful and the pain comes back nine months later, it’s reasonable to repeat,” Koehler said.

If the procedure is unsuccessful, the next step would be more extensive rehabilitation.

Without a fracture or any other sort of injury, surgery would not be a likely option for Miller. Repeated ablations, acupuncture, or physical therapy, are more standard.

“He’s a young athlete, so I imagine he would heal with time, unless it was a really severe injury,” Pazionis said.