Few would have predicted that Tiger Woods would be playing in the P.G.A. Championship this week. He had three failed back surgeries, starting in 2014. He had taken opioids. His astonishing career seemed over.
Then he had one more operation, a spinal fusion, the most complex of all, in 2017. And last month he won the Masters, playing the way he used to.
An outcome like his from fusion surgery is so rare it is “like winning the lottery,” Dr. Sohail K. Mirza, a spine surgeon at Dartmouth, said.
The idea behind spinal fusion is to remove a disk — a ring of fibers filled with a nerve-cushioning jelly that joins adjacent spine bones — and fuse the spine together, a procedure that almost inevitably means trading flexibility for stability and, the patient hopes, an existence with less pain.
That was all Woods was looking for when he decided to go ahead with fusion as a last resort — a “normal life” is how he put it. He got that and much more, including a new green blazer, though the lesson that most surgeons say Woods’s experience teaches isn’t that fusion surgery is a panacea but how much active rehabilitation and physical therapy the procedure requires for it to work.
“If you look at it simplistically, what does fusion do? It provides mechanical support,” said Dr. Charles A. Reitman, co-director of the Spine Center at the Medical University of South Carolina. “If they are missing mechanical support and that is the pure cause of the problem, then they will get better.”
People with a broken spine, for example, or scoliosis, which is severe spinal curvature, or spondylolisthesis, in which vertebrae slip out of place, tend to have terrific results, he said.
But those are a tiny minority of fusion patients. The vast majority of fusion procedures are performed on patients with one or more degenerated disks, disks that are worn out, dehydrated, stiff and friable. And when those disks move, patients’ backs can ache.
The solution sounds reasonable: Get rid of the degenerated disk and get rid of the pain. But maybe not. About half of middle-aged people with no back pain have degenerated disks. And at least half of patients in pain who have a fusion for a degenerated disk remain in pain.
Disabling lower back pain from degenerated disks often improves on its own, eventually. It’s not clear why because the disk is still degenerated. But the pain diminishes or even goes away.
“By middle age almost everybody has disk degeneration and a lot of people have back pain, but science has not been able to link the two,” Dr. Mirza said. “That’s the problem with fusion surgery for disk degeneration.”
Tony Delitto, chairman of physical therapy at the University of Pittsburgh, says he tries to warn patients seeking fusion surgery for a deteriorated disk not to expect too much.
“I would be very, very hesitant, and most surgeons would be very, very hesitant to tell patients that after fusion they would be pain-free,” he said.
Dr. Richard Deyo, an emeritus professor of medicine at Oregon Health and Science University, and his colleagues conducted a study in Oregon and found that about half of fusion patients who had the procedure on their lumbar, or lower, spine were using opioids before their operations. After their surgery, only 9 percent stopped using the drugs. And 13 percent who had not used opioids became long-term users after the surgery.
It’s hard to know what constitutes success, Dr. Deyo said. For example, one study, one of whose co-authors was Richard Guyer of the Texas Back Institute, who was widely reported to be Woods’s surgeon, reported a “clinical success rate” of 57 percent after two years. It defined clinical success as at least a 25 percent improvement in overall functioning, with no device failure, no major complications and no neurological deterioration.
By another definition of success — more than 30 percent relief of pain and 30 percent improvement in function — only about half of fusion operations succeed, Dr. Mirza said.
But the operation remains wildly popular — fusion surgery is among the top five operations in this country, and the vast majority are done for deteriorated disks. Only knee and hip replacement account for more inpatient hospital stays. Medicare pays for 300,000 of these operations each year, and private insurers are thought to pay for an equivalent number, Dr. Mirza said.
Woods is reported to have had deterioration of the bottom disk of his spine, the one that attaches to his pelvic bone. Surgery consists of removing that disk and replacing it with a metal cage. The space in the cage is then packed with bone.
Afterward, that segment of spine can no longer move — it is rigid. As a result, forces get transmitted to the area above and below the fusion or, in cases like Woods’s, where only the bottom disk is fused, to the disks above. Often, the disk or disks next to the fused one soon develop arthritis — as quickly as within a few years.
“If you were one of Woods’s competitors, you might say, ‘I might wait a little bit,’” said Dr. Steven Atlas, an associate professor of medicine at Harvard.
Dr. Atlas said he tells patients that it is one thing for an athlete like Woods to have that operation — it may be risky but he also might get a few more years out of his playing career, which could be worth millions of dollars.
But he cautions typical middle-aged patients. “Once they have that fusion, it can’t be undone,” Dr. Atlas said. “And it is likely that they will have future surgery down the road,” as a consequence of the instability fusion causes.
“If your goal is cure, that isn’t what this is going to offer,” he said.
Another option, for those willing to be patient, is intensive physical therapy. Large clinical trials found that those who take that route, as a group, have outcomes indistinguishable from those who have surgery.
But, Dr. Mirza, said, it has to be the right kind of physical therapy, strengthening muscles in the back, improving flexibility. Also, it’s unlikely Woods could have returned to the top of his sport with physical therapy alone.
“There is a tendency for rehab to involve passive treatments,” he explained, like ultrasound or traction or massage or dry needling. Those have not been shown to help.
The rehab also must be accompanied by behavioral therapy to teach patients not to be afraid of their back pain. “A lot of patients become terrified they will make things worse,” Dr. Mirza said. So they become deconditioned which does, in fact, make things worse.
On the other hand, suppose you don’t have time for all that physical therapy and counseling. You just want an operation to make the pain go away.
The problem is that you still need three to six months of physical therapy. After an initial period of near-immobility as the new bone in the cage in your spine heals, patients need to work on strength and conditioning.
Woods, surgeons suspect, most likely went far beyond the typical rehabilitation program.
Some, like Dr. Atlas and Dr. Mirza, say they try to talk most back pain patients out of fusion surgery, urging them to try conservative treatment first.
Dr. Steven Hughes, a spine surgeon in general practice in Northern Virginia, says careful patient selection for fusion surgery is crucial. He offers back surgery to only two or three of the 100 to 120 patients a week who come to him with back pain.
“If you are in a good surgeon’s office, fusion is the last thing you will be offered,” Dr. Hughes said.