Hi! I have a sacral dimple and so does Isaac. Here's our story...
I have clicky hips which gave me problems in my teens, no trouble walking, just pains. I had x rays and was told my hips are slightly deformed and may cause arthritis in later life and nothing more. Years and years later I was in hospital for something unrelated and was left with my notes. I read them and discovered the x rays I had as a teen showed I have spina bifida occulta and was never told. I confronted my GP who told me it was nothing to worry about and I wasn't told as it wasn't 'significant'

Anyway, I went to see a specialist who examined me and said I would be fine but would have to be checked along with baby if I ever got pregnant. Sometime later when I got pregnant with Isaac I had to have an appointment with the anaesthetist because spina bifida occulta can make epidurals tricky and Isaac also had an extra ultrasound to check his spine and hips, they looked fine. The conclusion was that I could have an epidural but it would be sighted higher than normal. As for Isaac he would have to have checks and scans when he was born and the risks were higher if I was having a girl. When Isaac was born he was checked over and it was found he had a sacral dimple, I was examined again and they found I have a sacral dimple too!!!!!! I never knew I had it!

Anyway, Isaac had scans and he is ok, he just has the dimple so although its nothing to worry about it can be a sign of spina bifida occulta which is a mild form of spina bifida and means the spine is slightly split but has no symptoms as such, apart from the dimple and sometimes a patch of hair or pigmentation on the back. I believe it can also cause bladder problems too but I don't know much about it. A few years ago I had a kidney infection and during routine tests it was discovered I have a double ureter coming from the kidney I
didn't have an infection in. They didn't link it to my spina bifida occulta but I'm sure it may be linked
Sorry for the essay, I've given you the quick version
If you are worried then get it followed up and ask about the spina bifida oculta. They haven't told me Isaac has it, just the dimple.