While the ‘harmonica’ pain is regular — you might say unremitting — every so often my central nervous system reminds me just how screwed up it is. Without warning I experience a sharp spasm of electric agony behind my left leg that renders me incapable of speech. I clutch my hamstring and grimace, barely breathing through my clenched teeth. If Linda is with me she rubs my back. It doesn’t do a damn bit of good but it reminds me that, at that moment, I am not alone. If I am alone, I sometimes scream. I am overwhelmed.

After 10-15 seconds the agony fades and after a final, forget-me-not jolt, it vanishes into the ether. Like the post-coital harmonica I am now pain-free, until the next time.

I liken these spasms to cymbals because they are sudden, sharp and, left to themselves, they produce a lengthy tone. Again they occur in the back of my leg (sciatic nerve again) but the precise site varies. They often invade during an otherwise calm period, just to keep me on my toes. They are also a comparatively recent phenomenon, perhaps associated with my trunk’s slow collapse into my wheelchair. The one thing that both sensations have in common is the heel, because the spasm invariably radiates down there. I remember my left heel once ruined a job interview. You know how vain types hate their profiles, or their ears, or their middle-age spread? I hate my left heel.

Every so often, I wonder why I bother taking drugs to ‘control’ pain like this. Sometimes, if I am enjoying an infrequent quiet patch, I will try to reduce the dosage. It won’t be long before I am forced to accept that, without them, life would be worse.

I get more excruciating pain but this is the most distracting and most regular, and I’m experiencing it right now. It starts in my left heel, often at its back and left, occuring every 3-4 seconds and lasting 1-2. It goes on for days (and nights) and there is very little I can do to mitigate it. It helps if I stand but I can’t do that for very long. It doesn’t respond to pain-killers. I hold my heel or, sometimes, the back of my knee to my chest — more for comfort than anything else. This is one of the reasons my left leg is now shorter than my right. Seriously. It’s over 4cm.

Sometimes I get relief from lying on my back on the floor. On occasion, usually when I’m in this position, the throbbing will build in intensity, and migrate to the back of that knee, building and building until I experience what I can only describe as a climax. Thereafter I can be blissfully pain-free for a few minutes, perhaps longer. If lying down, I can catch up with some sleep.

I often descibe this as sciatic pain distorted by the spinal injury, but I’m told that the relevant nerve is not damaged.