Can spinal surgery help low back pain sufferers?

Reproduced from Issue 130 of Arthritis Today

There are conflicting views about whether severe back pain can be improved by certain types of surgery, or whether it's better to leave the back to heal by itself. Jane Tadman looks at the pros and cons.

How many times have we heard someone say: "I just bent over and I felt something go in my back." Or they just sneezed or coughed, only to be incapacitated by excruciating agony, and had to lie flat on the floor until the pain subsided.

In most cases of this sort of back pain, time can be the best healer, although it can take weeks or months. But for some people the pain doesn't go away and that's when surgery can be the answer.

It's a similar story in older people with severe osteoporosis. Sometimes when the vertebrae in the spine crumbles the result can be appalling pain. Bed rest and painkillers used to be the standard treatment, but now there are surgical options available.

So what are the different types of surgery for back pain and sciatica?

Discectomy

Discs lie between the vertebrae in the spine, acting as shock absorbers, and allowing the spine to move. They have a jelly-like substance in the centre surrounded by a tougher outer ring. The discs are very close to the nerves which run from the brain to the legs, within the spinal cord. When a disc is damaged - often due to sneezing, coughing or lifting a heavy object with a bent back - and the outer layer tears, the jelly-like substance spills out, pressing on a nerve and causing pain. This pain, also known as sciatica, occurs when the prolapsed disc presses on the sciatic nerve, which runs from the lower back down the back of each leg. Painful symptoms can include burning or tingling down the leg, and a shooting pain that makes it difficult to stand up.

In 90 per cent of cases, the prolapse heals by itself over time, helped by physiotherapy and exercise.

In discectomy, all the jelly-like substance is removed to prevent risk of further prolapse, and the disc rapidly fills up with scar tissue. This type of surgery can also be performed as keyhole surgery, when it is called microdiscectomy. Although the usual place for a prolapse to occur is the lower back, it can also happen in the neck (the cervical spine). The success rate in terms of relieving leg pain is between 70 and 75 per cent.

Lumbar laminectomy

Lumbar laminectomy, (also known as decompression surgery) is performed on people who have stenosis – narrowing of the canal through which the nerves pass in the spinal column. This condition largely affects older people and is caused by osteoarthritis; degenerative changes in the spine that result in enlargement of the facet joints and surrounding ligaments, which then put pressure on the nerves, and can also reduce the blood supply to the nerves.

Some people manage to obtain sufficient pain relief from one or more steroid injections, but in others the pain, which can include numbness, tingling and pins and needles in the legs and feet, is too great.

Surgery involves cutting away some of the bone (called the lamina) that is pressing on the nerves to give the nerves more room. The nerves may not recover completely, and some numbness and weakness may remain, but the success rate in terms of ability to perform normal daily activities and in terms of pain relief is between 70 and 80 per cent. Some patients will continue to have back pain because of the arthritis in their facet joints which will be unaffected by the surgery. Laminectomy and decompression may also be performed as part of a discectomy.

In both these types of surgery there is a small risk that when the wound heals it creates scar tissue which creates more pressure and can lead to further problems.

Spinal fusion

Movement at a worn out or degenerated disc may cause back pain, and spinal fusion surgery is performed to fuse two or more vertebrae to prevent this movement. Wear and tear and trauma are causes for disc degeneration. Many people whose discs degenerate have no pain, but those who do may be able to manage with physiotherapy anti-inflammatories or steroid or epidural injections.

In fusion surgery the damaged disc is removed, and the vertebrae are linked together, either by a bone graft, which encourages the growth of new bone, screws, plates ad pins, or by the insertion of a cage into the space where the disc used to be, which encourages fusion between two vertebrae. Not only could removing the disc reduce pain, but the fusion stops the affected part of the spine moving. The downside of this type of surgery is that the vertebrae and disc next to the fused discs (often called adjacent levels) can then develop problems because of increased stresses.

Current clinical guidelines for managing chronic low back pain suggest spinal fusion for a very carefully selected and limited group of patients. The success rate in terms of reducing pain is between 60 and 70 per cent.

Disc replacement

A newer form of spinal surgery has been developed to offer an alternative to spinal fusion. The damaged disc is removed and replaced with an implant, made of metal or metal and plastic implant which should move like a normal disc.

The theoretical advantage of this technique over spinal fusion is that the replaced disc can move, and not transfer stress to other nearby discs. However disc replacements can break or become infected and may wear out. They are still in their early days and potential long-term problems are not yet known. Studies seem to show that they are as good but not better than a fusion operation after two years.

Vertebroplasty

Vertebroplasty is a relatively new procedure for treating the pain of spinal fractures caused by severe osteoporosis. Liquid cement is injected into the collapsed vertebrae to reinforce the crumbling bone, and to relieve pain.

The technique is not widely performed in this country, having gained a rather bad reputation in the States in the 1990s when it was performed in an unregulated way.

It is now approved by NICE in the UK as long as it is performed by appropriately trained people, usually a spinal surgeon working with a radiologist.

Vertebroplasty is an alternative treatment to bed rest and painkillers for selected patients. Some surgeons favour carrying out the operation immediately after a lumbar fracture, while others prefer to wait for up to six months to see if the pain will subside by itself.

It is carried out as a day-case procedure, with the patient sedated and under a local anaesthetic. Using X-ray guidance, the surgeon or radiologist will inject liquid cement into the collapsed vertebrae, which then sets hard.

A possible complication may occur if the cement leaks out of the bone and passes into the bloodstream and presses on the spinal cord, which then needs further emergency decompression surgery, but this is rare. Another potential problem is that if one vertebrae is stiffened by cement, then other weak bones in the spine will be put under more pressure and then fracture.

A similar technique called kyphoplasty is also available, which uses a balloon to create a space in the vertebrae which is then filled with cement. Some surgeons believe this technique is safer, and that the cement is less likely to leak.

Vertebroplasty and kyphoplasty are yet to be established into the mainstream of surgery, and many medics remain sceptical about their success. Spinal surgeon at Leeds General Infirmary Jake Timothy, who performs many vertebroplasties, believes that selecting the right patients to benefit the most is the key to its success. "I favour performing this sort of surgery early rather than waiting six months, because it's difficult to predict who will get better without surgery," he adds.

"Enforced immobility for three to four weeks is not only more expensive than surgery, but can lead to chest infection, bed sores and even death. It should at least be an option for a clinician to consider; it's a potential alternative to bed rest and morphine. Provided you know what you are doing and you have a controlled environment, it's a safe technique."

arc is currently funding research at the University of Leeds headed by Dr Nikil Kapur and Dr Richard Hall to develop the best types of cement to be used in vertebroplasty, (the same cement that is also used in some hip and knee replacements) and to identify ways of preventing cement leakage.

There remains some concern that spinal surgery may not be that successful in restoring people to their normal everyday activities. A recent report in the British Medical Journal , which compared the effectiveness of spinal fusion with an intensive rehabilitation programme for a select group of patients with low back pain, found no clear evidence that spinal fusion was more beneficial, suggesting that it plays only a small role in managing chronic low back pain. Many patients in both arms of the trial still had considerable disability after two years.

An arc -sponsored meeting of surgeons, physiotherapists, health economists and researchers recently identified some strategies for improving the outcome of spinal surgery, looking particularly at discectomies and laminectomies. Although both these types of surgery can be effective in relieving pain, many patients do not return to work or normal activities after surgery, and remain chronically disabled.

The group found that several small, recent trials had revealed that a vigorous post-operative exercise regime led to a more rapid return to work. They decided to pursue research that would examine specifically the impact of post-operative rehabilitation, working on the thesis that by the time many patients with low back pain undergo surgery, their spinal muscles were seriously de-conditioned.

The result is the current arc -funded clinical trial led by Dr Alison McGregor in hospitals in west London , (featured in edition 129 of Arthritis Today ) which should establish whether intensive rehabilitation improves the outcome of discectomy and laminectomy.

arc -funded research by Dr Trish Dolan at the University of Bristol already indicates that exercise after microdiscectomy for a prolapsed disc can help patients recover more quickly. In her study, two groups of patients who had undergone surgery were followed up for two years. One group had post-operative exercise between four and eight weeks after surgery, while the other group did not. While both groups showed marked improvements in terms of pain, disability and depression after surgery, the group who had taken part in the exercise programme had much better range of movement in the spine and hips, and stronger back muscles. After two years' follow-up there were few differences between the groups.

Spinal surgeon Naffis Anjarwalla has no doubt that rehabilitation after surgery helps patients recover better, but believes it is unrealistic to think that every patient can be referred for physiotherapy because of sheer weight of numbers, and the length of time they would have to wait.

However, if further research proves conclusively that this approach enables patients to get better more quickly and take up their old lives again, it would put pressure on health managers to re-think current practice.

What is certain is that spinal surgery is at least an option for patients with severe back pain who have run out of other alternatives.

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