Isthmic Spondylolisthesis

Hello.

Many young people suffer from back pain but it is usually the kind of pain that gets better by itself over a few days to weeks. Occasionally, though, back pain can persist and it may become worth investigating, especially if it is associated with leg pain, or “sciatica”. A particular condition that can cause lower back pain and sciatica in younger people is isthmic spondylolisthesis. Well what on earth is that, you ask.

Isthmic spondylolisthesis, or IS, for short, is a condition that you might think of as a stress fracture in your lower back. It usually develops when you’re a teenager, and it occurs more frequently in sportspeople that perform a lot of extension activities like gymnasts, fast bowlers and baseball pitchers, but it can occur in people who don’t play any sport either. If it is picked up when you’re really young sometimes the problem, or “defect”, can be repaired. Unfortunately, it often goes unrecognised and only later in life becomes symptomatic.

The defect is in a part of the spine called the “isthmus”, or “pars interarticularis” (pars for short). It is most common at L5, and most commonly leads to a spondylolisthesis, or “slip”, or L5 on the sacrum.

The progress of isthmic spondylolisthesis

isthmic spondylolisthesis

As you can see in the diagram to the right, the pars links the L5 vertebra to the sacrum. If this is broken, the L5 vertebra is only held onto the sacrum by ligaments, and these over time stretch and may fail. This includes the disc between L5 and the sacrum. If you think about it, the whole weight of your upper body – your head, arm, thorax and abdomen – is all bearing down on this segment of your spine, so it’s no surprise that over time, if there’s no bone holding them together, that the ligaments will fail.

So that’s what it is. What can be done about it? You’ll have to wait for my next post…

John