MARCH / APRIL 2007

AROUND HARVARD

This article originally appeared in the February 2007 Harvard Health Letter and is provided courtesy of Harvard Health Publications.

Back surgery: To have or not to have
Indecision is understandable, even a good idea, in light of inconclusive research results and lack of clear physical indicators.

Is your back bothering you at the moment? Do you have a history of back problems? If you answer “yes” to one or both of these questions, you’ve got lots of company. Low back pain is an extremely common condition: 80% of Americans experience at least one bout of it some time during their lives. Rest, some pain relievers, and perhaps some exercises help it go away.

But for many millions, the pain lingers and may become severe and debilitating. Depending on the underlying cause, surgery is an option.

Deciding to have surgery is never simple, but it’s especially difficult when the back is involved. Many of the studies of back surgery have been small. Popular procedures have been questioned, and new ones get introduced before we really know how well they’ll work over the long haul. Physical changes to the spine may cause excruciating pain in one person, but no pain in another, so it’s hard to go by physical findings. There are also huge variations in practice patterns, so in some parts of the country certain types of operations are performed often, while in others, they’re done less often. Researchers have documented differences of 15-fold. Are doctors in the high-surgery regions too quick to operate, influenced by tradition, facilities, and financial incentives? Or are surgeons in the low-surgery areas behind the times?

It’s hard enough for doctors to figure out what to do about surgery for back pain. Patients are often even more confused.

Back basics
Although we talk about strong-willed people having backbone, your spine is actually a flexible, curvaceous stack of 24 vertebrae (33 if you count the fused vertebrae of the sacrum and coccyx). They are held together by tough, yellow ligaments, and the spinal cord runs down a space in the middle. The five lumbar vertebrae are the largest, as they should be, because they must support much of your body weight when you’re upright. Most back problems come from this lower, weight-bearing region — thus the “low” in low back pain. You don’t hear it used much anymore, but lumbago is a word for low back pain.

In between the vertebrae are the disks, so infamous for “slipping.” Their outsides are made of a tough, fibrous tissue (annulus fibrosus) that holds a squishy substance (nucleus pulposus) inside. Intervertebral disks (that’s the full medical term) are a little like mini–water beds that cushion the vertebrae so we don’t have bone rubbing on bone. Unfortunately, as we get older, our intervertebral disks gradually dry out, so by about age 50, the tough exterior and soft interior merge. They also thin out, which puts additional pressure on the vertebrae and makes the back less flexible.

Three categories
Most back pain can be grouped into three major categories:

 Sprains and strains. These are the most common causes of back pain. The pain is the result of damage to the ligaments or muscles — the “soft” tissues — that support the spine. Sprains are injuries to ligaments. Strain is a general term that’s usually used in reference to muscle. If it isn’t too serious, a back sprain or strain will often clear up in a few days or weeks as long as you give it some rest, perhaps take an over-the-counter pain reliever, and, in more serious cases, get some physical therapy. But recurrence is common. Without following a regular exercise program that stretches and strengthens back muscles and ligaments, about 40% of patients will have another episode within a year.

 Pinched nerves. This category includes any condition that compresses the roots of nerves as they peel off in pairs from the spinal cord, a little like the off-ramps coming off a major highway. (A brief, technical aside: Although they’re commonly referred to as pinched nerves, strictly speaking these spine-related conditions impinge on the roots of nerves. Nerve roots become nerves an inch or so out from the spinal cord.)

Herniated disks (a slipped or ruptured disk is the same thing) are the main cause of spine-related pinched nerve roots. The outer casing of the disk weakens and gives way, so the nucleus pulposus — the gelatinous substance inside — pushes out and causes a bulge. If the bulge sticks out too far, or a piece of the misshapen disk breaks off, it can irritate the nerve root (see illustration).

Sometimes the disk impinges on the root of the large sciatic nerve that supplies the back of the leg. The result is sciatica — pain and numbness that radiates down the buttock and the thigh and, sometimes, all the way to the toes. Sciatica can be confusing because sometimes it skips the buttocks and thigh, so the pain is felt only in the knee.

Spinal stenosis is the other major pinched nerve syndrome and a common problem in older people. The spinal cord and nerve roots thread through openings in the vertebrae with little room to spare. Spinal stenosis occurs when bone spurs (osteophytes) and other tissues narrow these openings, so the nerve tissue gets squeezed and irritated. Symptoms often include leg pain, cramping, and weakness that gets worse with standing or walking. As with sciatica, these leg problems may not seem like they’re coming from the back.

 Degenerative diseases. With age, vertebrae get brittle and break, even without a fall or some kind of trauma. In addition, the spine’s facet joints, where the vertebrae interlock with one another, tend to get arthritic as we get older.

Decisions, decisions
You don’t get surgery for sprains and strains. Rest is important, but bed rest of more than a couple of days is counterproductive; you and your back rapidly get out of shape. A return to normal activities as soon as possible is the best medicine for a sprain or strain.

Surgery is used to treat pinched nerves. If you have a herniated disk, the part that is impinging on the nerve can be removed. Lumbar diskectomies, as these operations are called if they involve disks in the lumbar region, are the most common operation for back and leg problems in the United States. Although the complication rate is low, they’re controversial because people often get better without having an operation.

Tie goes to patient preference
Findings from a clinical trial reported in November 2006 in the Journal of the American Medical Association stirred the lumbar diskectomy pot a little more. The study involved about 500 patients with herniated disks and leg pain. They were randomized to either surgery or nonsurgical treatment and then followed for two years. Nonsurgical treatment was left to the discretion of the doctors and patients, and it ran the gamut, from pain relievers to physical therapy to acupuncture to steroid injections.

The results are tricky to interpret because so many patients “crossed over” to the treatment to which they weren’t originally assigned. Almost half (45%) of the patients randomly assigned to the nonsurgical approach ended up having surgery. A similar percentage who were supposed to get surgery elected not to have it.

The researchers said the crossover and other factors probably mean the effects of surgery are underestimated. By some measures (sciatica pain, self-reported progress) the surgical patients did fare slightly better. Results from a companion study that wasn’t randomized suggested that surgery may provide quicker relief.

Still, the overall results from the main randomized study showed no statistical difference between surgery and nonsurgery — although don’t equate nonsurgery with nontreatment. This study was widely interpreted as showing that lumbar diskectomy may not be warranted, considering that people assigned to nonsurgery did just as well after two years. But another interpretation is that all the nonsurgical treatments for herniated disks have caught up with diskectomy.

An editorial accompanying the study said toss-up results show that the decision whether to have surgery is a matter of patient preference more than anything else.

Spinal stenosis surgery
Spinal stenosis can be treated surgically by removing bone spurs or parts of the vertebrae (laminae, portions of the facet joints) that are pressing in on nerves. Studies have shown good results, with any lingering pain controlled with medication.

Degenerative disease can be treated with spinal fusions, an operation that involves grafting two neighboring vertebrae together to create more stability. But doctors are beginning to question whether too many spinal fusions are being done, and some research calls into question how effective they really are.

Don’t rush into anything
Barring an emergency, it’s a good rule of thumb to put off surgery for at least six weeks after symptoms start. In many cases, waiting allows the problem to improve by itself. Ideally, patients have primary care physicians who are well acquainted with common back conditions and can steer them to an effective treatment.

Specialists can bring great expertise and experience to bear on any medical conditions, back pain included. Just be aware of their vantage point. Back surgeons tend to see back problems as having surgical solutions.

Older, experienced back surgeons who have stopped performing surgery have started working as consultants. Familiar with the choices but no longer performing surgery, they may provide the right mix of experience and objectivity.

Copyright 2007 Harvard Medical International