I had to have mine replaced at the hospital, and was not given the option to do it in the office. It is an outpatient procedure as long as it is just the port, but I still had to have general anesthesia. Your issue sounds identical to mine as it appears you are able to maintain volume up to a point where it seems extra pressure forces the saline out. I could always maintain about 3.5 - 4 ccs, but the pressure of the additional saline caused it to leak out. Good luck. The procedure was not a big deal at all, but I don't know how it would be in the office.