I haven’t had bladder instillations for my IC so far.
Here is an NHS writeup about bladder instillations.
Recently I heard a horror story about a bladder instillation procedure not being performed correctly as a result of which the patient was left in severe pain for several hours and really traumatized.
I have had the TENS procedure around 10 years back but it didn’t really work for me and infact made my symptoms worse.
Elmiron worked for me and decreased the pain and frequency.The drawback with Elmiron is that it is extremely expensive.