**Core Concept**
The spleen is a highly vascular organ, and injury can lead to significant bleeding. Conservative management of splenic injury involves preserving the spleen to prevent long-term consequences such as increased risk of infections and osteoporosis. This approach is based on the concept of splenic artery embolization and the use of non-invasive monitoring techniques to assess the spleen's function.

**Why the Correct Answer is Right**
The correct answer is **A: Haemodynamically stable patients with a splenic injury**. Conservative management is preferred in patients who are hemodynamically stable, meaning their blood pressure is stable, and they do not have signs of significant bleeding. This approach involves close monitoring of the patient's vital signs, serial abdominal exams, and the use of imaging studies such as CT scans to assess the spleen's function. The spleen's function is preserved by minimizing the risk of infection and preventing long-term consequences.

**Why Each Wrong Option is Incorrect**
**Option B:** **Patients with a splenic injury who are hemodynamically unstable**. Conservative management is not suitable for patients who are hemodynamically unstable, as they require immediate surgical intervention to control bleeding.

**Option C:** **Patients with a splenic injury and a history of previous abdominal surgery**. The presence of previous abdominal surgery does not necessarily preclude conservative management, but it may increase the risk of complications.

**Option D:** **Patients with a splenic injury and a significant head injury**. The presence of a significant head injury does not preclude conservative management of the splenic injury, but it may require careful monitoring and consideration of the patient's overall condition.

**Clinical Pearl / High-Yield Fact**
It is essential to remember that conservative management of splenic injury is not suitable for all patients, and the decision to pursue this approach should be based on individual patient factors and the severity of the injury.

**Correct Answer: A. Haemodynamically stable patients with a splenic injury**