I have developed real problems with sciatica - my back doesn't hurt, but my ankle stopped me running, and I have numbness occasionally under my foot. It has got much better since I stopped running and started using a cross trainer, but I do miss running. Do you think I will ever be able to run again?
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Low back pain and sciatica (pain along the sciatic nerve) are one of the curses of modern life. In most instances, sciatica is due to a disc - the soft tissues between the vertebrae (the bones that compose the spine) - being squeezed out and compressing one of the nerve roots, causing pain in the leg. If symptoms do not abate after a few weeks with rest, mobilisation and painkillers, more invasive procedures are contemplated.

Nowadays, some surgeons are performing disc-replacement surgery instead of just excision of the disc (so-called laminectomies), or excision and subsequent fusion of the spine. These operations relieve pain along the leg, at times immediately after the anaesthetic has worn off. If the pain is accompanied by loss of sensation along the leg, this takes significantly longer to recover, and some patients may never return to normality.

Most surgeons recommend that patients abstain from high-impact activities following surgery,: the disc cushions stresses to the spine, and there is the real danger that the spine will develop degenerative joint disease and osteoarthritis. Stating that a patient should never run again is probably a bit harsh, but rightly cautious. Alternative low impact, gentler-on-the-spine outdoor activities can be a decent - though not perfect- substitute to running. Cycling, in-line skating and power walking can be equally taxing on the cardiovascular system but easier on the spine.

· Nicola Maffulli is a consultant orthopaedic and sports injury surgeon at Keele University Medical School. If you have a question for him, email fitness@theguardian.com