**Core Concept**
The management of kidney injuries involves a careful assessment of the severity of the injury, with surgical exploration being considered for more severe cases. The American Association for the Surgery of Trauma (AAST) organ injury scale is used to grade kidney injuries, with higher grades indicating more severe injuries.

**Why the Correct Answer is Right**
The correct answer is based on the AAST organ injury scale, which categorizes kidney injuries into five grades. Grades I-III are typically managed conservatively, while grades IV and V often require surgical exploration. Grade IV injuries involve a laceration or vascular injury that extends beyond the renal cortex, and grade V injuries involve a shattered kidney or vascular injury that is not amenable to repair. In general, about 10-20% of cases with grade IV or V injuries require surgical exploration.

**Why Each Wrong Option is Incorrect**
**Option A:** 5% - This is an underestimation of the percentage of cases that require surgical exploration, as it does not account for the more severe grades of injury.
**Option B:** 50% - This is an overestimation, as the majority of kidney injuries are managed conservatively.
**Option C:** 80% - This is an overestimation, as surgical exploration is typically reserved for more severe cases.

**Clinical Pearl / High-Yield Fact**
The AAST organ injury scale is a useful tool for assessing the severity of kidney injuries and determining the need for surgical exploration. It is essential to remember that the scale is not a substitute for clinical judgment, and the decision to operate should be based on a combination of factors, including the mechanism of injury, the severity of the injury, and the patient's overall condition.

**Correct Answer: C. 10-20%.**