The specific volume of the bladder needs to be measured because the bladder volume is relatively small. This is often seen in cases of contracture of the bladder due to tuberculosis infection, or contracture of the bladder due to prolonged catheterization with an indwelling cystostomy tube. To measure the volume of the bladder, a catheter is left in place and sterile saline is injected into the bladder, and the patient feels unable to hold the urine when the injected volume is released to observe the exact volume of the bladder. If the volume of the bladder is measured to be less than 50 ml or less, bladder enlargement treatment using surgery is recommended, otherwise the patient suffers from severe urinary frequency caused by a small bladder, which affects the quality of life. If the volume is above 50 ml, then it is recommended that the catheter can be temporarily left in place to train bladder function by intermittently clamping the catheter and holding urine appropriately to observe whether the bladder capacity can be expanded. If the bladder volume does not expand significantly after three months of continuous observation, then surgical treatment for bladder enlargement needs to be considered.