Fosamax and spinal anaesthesia

Q About a year ago, I was given a spinal injection for a suspected hernia which has left me with a very painful lower back. Have you come across other people with long-term lower-back pain after a spinal injection? Is there anything I can do to rectify the problem? - MA, Lytham, Lancs

A Giving anaesthetics through needles into the spine is becoming more popular mainly for reasons of cost. The patient recovers immediately after the operation, unlike general anaesthesia, which usually involves the expense of an overnight stay in hospital. But these short-term benefits have to be balanced against the long-term dangers.

Injecting anything into the spine is intrinsically hazardous since the spine acts as the trunk carrier for all the nerves that carry messages to and from the brain. Some people have become paralysed as a result of misplaced anaesthetic needles.

There are two sites in the spine that anaesthetics are usually injected into. The first is the space around the membranes surrounding the spinal cord - an ‘epidural’ (‘epi’ means ‘outside of’, and ‘dural’, refers to the dura mater, the outermost membranous covering of the spinal cord) anaesthesia. The second site is between two vertebrae in the lower part of spine, which requires even more delicate and precise needling, and is called spinal anaesthesia. It’s normally given before operations on the legs or lower abdomen, as in your case.

Although there are very few investigations into the long-term effects of either type of anaesthesia, low-back pain does appear to be a major complication. A groundbreaking British study by the University of Birmingham (BMJ, 1990; 301: 9-12) showed that nearly 20 per cent of the women given epidurals during labour subsequently went on to suffer persistent low-back pain. A clue to the cause of the problem came from autopsies, where pathologists found 'non-specific inflammatory reactions' in the spine of people who had epidurals. In many cases, there was also evidence of epidural infection (Anaesthesia, 1990; 45: 357-61).

There’s even less data on persistent low-back pain after spinal anaesthesia, even though the problem was first identified nearly 50 years ago (JAMA, 1956; 161: 586-91). In recent times, only two studies have looked at long-term problems. In one, Canadian sports doctors found that spinal anaesthesia caused low-back pain in as many as 45 per cent of cases - even in young people (Can J Sport Sci, 1991; 16: 167). In the other, Austrian neurologists found that low-back pain was one of the major long-term problems of the procedure (Trop Med Int Health, 2001; 6: 34-6).

Having acquired iatrogenic (doctor-induced) low-back pain, how can you get rid of it? What the spinal anaesthetic has done is set up inflammation around the spine, causing the back muscles to spasm. This is the probable cause of the pain.

A number of alternative treatments may work for you, such as osteopathy and its sister treatment, chiropractic. A landmark study compared chiropractic with physiotherapy specifically for low-back pain. The results confounded the sceptics, as they showed that those who received chiropractic treatment were nearly 30 per cent more improved than the physiotherapy group (BMJ, 1995; 311: 349-51). A later, multi-trial analysis largely confirmed the value of spinal manipulation in general (Spine, 1996; 21: 2860-71).

So, a good osteopath or chiropractor will almost certainly be able to sort out your problem. If you don’t like the idea of being manipulated, find an osteopath who offers cranial osteopathy, a totally non-invasive form of treatment.

Acupuncture, too, may help. This alternative treatment has been scientifically tested in low-back pain and found to be of benefit. One study showed that pain levels were halved after 40 weeks of treatment (Am J Chin Med, 1980; 8: 181-9). Even better is electroacupuncture, in particular with low-frequency (2-Hz) electrical stimulation (Acta Anaesthesiol Scand, 1994; 38: 63-9).

Another electromagnetic therapy is TENS (transcutaneous electrical nerve stimulation). Just four weeks of TENS treatment can reduce both low-back pain and the use of painkilling drugs (Pain, 1999; 82: 9-13).

Conventional massage has also been found to help the condition, and may be even better than acupuncture for this type of pain (Arch Intern Med, 2001; 161: 1081-8).