As an update I saw my spine doctor on March 3rd and asked him whether my urinary retention could have been caused by the disk herniation. He looked at my MRI again and said that typically bladder nerve issues result from nerves in the center of the spinal column, and my herniation wasn’t near there. His opinion was that the two were unrelated. He also said that typically spinal nerve damage would result in incontinence, not retention
Saw my urologist the following week and the ultrasound revealed 400 cc of urine. Got trained for self-catheterization and started self-catheterization on March 14, twice per day. Initially I was terrified but have gotten somewhat used to it since. I do it before I go to bed and again mid-morning. Only twice have I gotten up to pee in the middle of the night, and only once per occasion - so I'm sleeping a lot better

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Today I met with a surgeon at Mayo to discuss surgical options. He said that although he wasn't 100% sure that the prostate size was causing my retention, the results from the urodynamics test indicated that my bladder still had strong enough contractions to suggest that prostate reduction surgery would be beneficial, and recommended that HoLEP would be best indicated for me. He recommended HoLEP based on prostate size, location, recovery time, and has done approximate 1,500 surgeries.
So, because I have read good things about HoLEP and felt good with the surgeon, I scheduled the surgery for May 1st. In the meantime I will continue to self-catheterize.