My brother had kyphosis surgery 6 days ago and is still unable to urinate. he's going home with a catheter. what can be the cause?

Here are some ...: It's not uncommon to develop temporary/permanent bladder dysfunction after spinal surgery of this nature. Either one, the care for such postop conditions remains the same, that is, to avoid any further bladder damage by bladder over-distention with indwelling catheter or clean intermittent self-catheterization (CISC). Medically, CISC does better for convenience & infection. For now, indweling is o