Hello and welcome to HCM.
Thank you for your query.
First of all, coming to the bladder suspension and
hysterectomy, both of which are common causes to recurrent
urinary tract infections (UTI). In your case, your doctor does sound experienced enough and has found the cause to be
urinary retention, which could be most accurate.
The new technique to treat this is very effective, and my advice would be to go ahead with it at the earliest. When a solution is known, there is no reason to delay it.
Now coming to the baking soda. Your acquaintance is right. Having baking soda with water either during an infection or even as prophylaxis helps in neutralizing acidic urine, which when taken during an infection can help relieve symptoms of a UTI, and when taken in the absence of an infection can ONLY help individuals who have a diet or medication that result in acidic urine. It can be used to reduce symptoms of a UTI in your case, but would not help much to prevent the infections.
I hope I have succeeded in providing the information you were looking for. Please feel free to write back to me for any further clarifications. I would gladly help you.
Best wishes.