Unlikely. The needle used for a spinal or epidural injection does not come into contact with the bladder. Patients who receive a spinal or epidural injection will often also receive a foley (bladder) catheter to drain the urine from the bladder because the spinal/epidural may inhibit the ability to urinate. This catheter is the more likely cause of a bladder infection.
Highly unlikely. Highly unlikely that placing a needle into the back would lead to an infection in the urinary tract.
No. The effects of prolonged spinal/epidural anesthetic can sometimes mean the "slow" return of normal bladder function (urination). If a catheter needs to drain your bladder until normal function returns, an infection from the catheter placement is possible, though highly unlikely. The reason is this: in this circumstance, the catheter is in place for such a short time, infection is unlikely.