**Core Concept**
Splenectomy is a surgical procedure to remove the spleen, often performed in patients with immune thrombocytopenic purpura (ITP) who have failed medical therapy. The timing of platelet transfusion before splenectomy is crucial to avoid complications.

**Why the Correct Answer is Right**
The optimal time for platelet infusion in a patient undergoing splenectomy for ITP is pre-operatively, particularly 4-6 hours before surgery. This timing allows for the platelets to be sequestered in the spleen, thereby reducing the risk of post-operative thrombocytopenia. The infused platelets will be removed from the circulation by the spleen, which will be subsequently removed, thereby preventing the patient from developing thrombocytopenia post-operatively.

**Why Each Wrong Option is Incorrect**
**Option A:** Platelet transfusion post-operatively is not recommended because the patient may develop severe thrombocytopenia due to the sequestration of platelets by the remaining splenic tissue.

**Option B:** Platelet transfusion immediately before surgery is not ideal as it may lead to an immediate increase in platelet count, making it difficult to assess the true pre-operative platelet count.

**Option C:** Platelet transfusion on the day of surgery but after the surgical incision is made is not recommended as it may not provide sufficient time for the infused platelets to be sequestered by the spleen.

**Clinical Pearl / High-Yield Fact**
In patients with ITP undergoing splenectomy, platelet transfusion should be performed pre-operatively to avoid post-operative thrombocytopenia.

**Correct Answer:** C.