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.

Trouble emptying the bladder after surgery (acute urinary retention, AUR) is a common and important problem in adults who receive numbing medicine in the lower back (spinal anesthesia). AUR can cause pain, an overfilled bladder (bladder distension), urinary tract infection, longer hospital stays, and higher health care costs. The usual way to manage AUR is to place a tube into the bladder to drain urine (urinary catheterization). This works, but it is invasive and may lead to infection, injury to the urethra, and discomfort. Because of these risks, there is a need for simple, non-drug, non-invasive nursing methods to help prevent AUR.

Spinal anesthesia can temporarily block normal bladder function and increase the risk of AUR. Nurses are often the first to notice when a person is unable to pass urine and are in a key position to provide early, preventive care. Some studies have looked at different nursing interventions for urinary retention, but there is little evidence about non-invasive methods after spinal anesthesia, and no trial has directly compared a cold pack on the lower belly with a massage over the tailbone in this setting.

This randomized controlled trial will include adult surgical patients who receive spinal anesthesia for operations in the scrotum (scrotal), groin (inguinal), pelvic area, lower belly (lower abdominal), or bones and joints (orthopedic surgery). Participants will be randomly assigned to one of three groups:

1. a dry cold pack applied to the lower belly over the bladder (suprapubic area),
2. gentle massage over the lower back in the area of the tailbone (sacral area), or
3. usual postoperative care without an extra study procedure.

All study procedures in all three groups will be carried out by a single nurse researcher, using the same assessment steps for every participant. The aim is to keep the care consistent and reduce differences that are not related to the study methods.

The main focus of the study is to find out whether these nursing methods can lower the rate of acute urinary retention after spinal anesthesia. Nurses will regularly check how well participants can pass urine on their own and will estimate bladder volume using a small, painless scan placed on the skin over the lower belly (portable bladder ultrasound device). This objective measurement is expected to improve early detection of AUR compared with relying only on symptoms or physical examination.

The study will also look at related outcomes such as time to first spontaneous urination, need for urinary catheterization, bladder fullness and pain, and comfort and satisfaction with nursing care. By providing clear, comparative information on two simple, non-invasive nursing interventions, this trial aims to support evidence-based postoperative nursing protocols, improve patient comfort, and reduce the need for invasive urinary catheterization after spinal anesthesia.

Inclusion Criteria: Patients who meet all of the following criteria will be included:

• Age 18 years or older
• No diagnosis of urolithiasis, benign prostatic hyperplasia, neurogenic bladder, cancer, or other malignancy
• No diagnosis of urinary tract infection within the last month
• No history of prior urological surgery or surgery involving the sacral region
• No history of urinary retention
• Not using antidepressants, antipsychotics, muscarinic receptor antagonists, alpha-blockers, or similar medications
• No contraindication for applying cold to the suprapubic area or massage to the sacral area (e.g., no pacemaker, bladder stimulator, or other sensitive electronic medical device in the sacral region)
• No visual, hearing, cognitive, or perceptual impairment

Exclusion Criteria:Patients who meet any of the following criteria will be excluded:

• Duration of surgery longer than 2 hours
• Urinary catheterization performed preoperatively, intraoperatively, or postoperatively
• Blood transfusion performed preoperatively, intraoperatively, or postoperatively
• Development of complications such as hypothermia, bleeding, or other conditions that prevent the application of dry cold or sacral massage in the preoperative, intraoperative, or postoperative period
• Transfer to the intensive care unit after surgery.

Participants will be randomly assigned to one of three groups using a computer-generated random sequence (Randomizer.org), with group allocation concealed in sealed opaque envelopes until enrollment. All interventions will be delivered by a single nurse researcher, who will be aware of group assignments. However, the data will be analyzed by an independent expert who will be blinded to group allocation and will work with de-identified, coded data only.