While he doesn't question that patients feel leg pain, he says the condition is all but impossible to diagnose - and may be caused by nerves irritated elsewhere in the body, "anywhere from the toes to the brain."
Filler and others say that when back treatments and back surgery don't work, practitioners sometimes label patients as neurotic malingerers whose pain is psychosomatic. "Doctors, and in particular surgeons, like to think that they are all-knowing and all-capable," he says.
Michael Edelman went through some of this frustration. In the mid-1990s, he began to suffer "excruciating" pain in his right hip that radiated down the side of his leg to his calf. He went to doctor after doctor, and underwent physical therapy, back injections and massage. Nothing helped.
"I was very frustrated," says Edelman, a 58-year-old personal injury lawyer and political consultant who lives in a suburb north of New York City. "I was walking around in constant pain."
After several years, he heard about Loren Fishman and made an appointment. The doctor diagnosed piriformis syndrome, and prescribed stretching and injections to relax the muscle.
Edelman says the pain lessened dramatically. He still gets occasional treatment when his piriformis tightens up, but he now plays golf three times a week. Before seeing Fishman, he had all but given up the game.
Fishman injects many of his piriformis patients, including Edelman, with Botulinum toxin, or Botox. In recent years, many doctors have used Botox for a variety of muscle- and nerve-related pain problems. It blocks nerve signals, relaxes muscles and decreases pain.
In piriformis cases, physical therapy and injections don't work. Some patients undergo surgery to pare or remove the muscle, reducing the strain on the sciatic nerve. Filler, who has developed a minimally invasive version of the surgery, says that about 90 percent of patients improve after the procedure.
Tiel argues that the surgery remains unproven, and suggests that post-treatment improvement in those who undergo it may be because of the placebo effect - when patients improve just because they believe they have been treated.
"I always like to understand the problem before I treat it," he says.
Filler disagrees, referring to a study he published last year that found many subjects who underwent successful piriformis treatment had previously had unsuccessful back therapy.
"How does the patient get no placebo effect from spinal treatment, but get a placebo effect from my piriformis injections?" he asks.
With so much ideological distance between the sides, the debate is not likely to be resolved soon. But all agree that the dispute has at least raised awareness of the issue. Scott Fishman says that more doctors around the country are considering piriformis syndrome as a potential diagnosis.
"It is real and it does occur," he says. "We need to look for it and treat it, because it is treatable."