The above picture had to have been a lot of work, given that there was a lot of the background obscured in the original. You will also notice that the "artist" alternates between cueball smooth and 2-day stubble. It is quite disconcerting.
I would hazard a guess that this person repeatedly wore out their copy of Star Trek: The Motion Picture.
I have found it helpful to do the stretching exercises my physical therapist recommends. Do some core strengthening exercises, such as the ones highlighted at The Mayo Clinic. By keeping your core strong, your back won't put itself in a position to cause that sciatica pain you are having.