Bladder Pressure Criteria Questions for Nurse or Dr Wise

I am a 59 yr old C1/C2 who has had a very good recovery. I can walk ten miles, ride my bike 80 miles and I have pretty good bowel and bladder. After four weeks in ICU and CCU, Upon entering rehab, they removed my catheter, and I have been voiding voluntarily for five years. Lately I have been cathing once a month to monitor my post void residual. This month I voided 300 ml and had a residual of 100 ml. Recently my Urologist gave me a kidney ultrasound and a urodynamics test. The ultrasound showed no problems, but the urodynamics result was 86 cm h2o peak pressure, 52 cm h2o mean pressure, and 14 cm h2o pressure at peak flow. He is recommending that I start using Ditropan, and, if that prevents voluntary voiding, that I do intermittent catheterization. I am hesitant to do that. My questions are:
Which pressure, mean or peak, should be evaluated?
How high will cause kidney damage?
I would like to read the research that shows this. Can you cite a paper?

Thank you so much for your time.

Bladder Pressure Criteria Questions for Nurse or Dr Wise