I think you are quite right to point out the very high potential for urinary retention with seeds. I recent multi-institutional study found that your experience is not uncommon, and such urinary obstructive symptoms may persist in a few men even two years later.
At 2 months following implants, there was a 33% increase in rating of their symptoms as "moderate to severe" compared to their pre-treatment ratings. Most of that was due to obstructive symptoms. By 2 years later, that had fallen to a 7% increase.See third table
I have a question for you that you may know the answer to -- does Beaumont still offer HDR brachytherapy now that Alvaro Martinez has left?