@brr, how frustrating that the bladder sling was successful in helping incontinence, but has caused another problem with not being able to completely empty. I'm tagging @baxtersmom@gardeningjunkie@hotfooted and @luftmensh1 to see if any of them have experienced a similar issue.
I can imagine that you would be nervous about cutting the sling and wondering if that might cause incontinence to return. Did the doctor think that the scar tissue is causing the sling to be too taut or tight? I would want to ask questions like "Does cutting the sling risk more scar tissue? Could incontinence return? Can you draw me a picture of how cutting in the center will help?"