"Concerned over my forgotten re-call"

I have for the past 6 months been having treatment for kidney stones and the last time I went in was in June and I had a stent re-fitted and it wasn't till I complained that a new date was fixed which will mean that I will have had this stent in for over 12 weeks as it appears that the specialist had forgotten to fill in the relevant forms for me to be automatically recalled.

My worry is that because I was able to chase this up ,what would happen to someone who for whatever reason could not do this, someone more elderly who thought the hospital would deal with them properly. Would they be left with something still inside them?