Postoperative Urinary Retention

The goal of this clinical trial is to learn whether two simple nursing methods can help prevent trouble emptying the bladder (acute urinary retention, AUR) after surgery with numbing medicine in the lower back (spinal anesthesia). Adults having surgery in the scrotum (scrotal), groin (inguinal), pelvic area, lower belly (lower abdominal), or bones and joints (orthopedic surgery) with spinal anesthesia will take part. After surgery, participants will be randomly placed into one of three groups: one group will receive a cold pack on the lower belly (suprapubic area), a second group will receive a gentle massage on the lower back over the tailbone (sacral area), and a third group will receive usual care only with no extra procedure. The same nurse researcher will provide the study care for all groups, check how well participants pass urine, use a small painless scan on the lower belly to see how much urine is in the bladder (portable bladder ultrasound), and record whether a tube in the bladder to drain urine (urinary catheter) is needed.