**Core Concept**
Thoracotomy is a surgical procedure that involves opening the thoracic cavity, which can lead to severe postoperative pain due to the disruption of intercostal nerves and the musculature of the chest wall. Effective pain management is crucial to prevent complications such as respiratory distress, atelectasis, and prolonged hospital stay.

**Why the Correct Answer is Right**
The correct answer is **Epidural Analgesia**. Epidural analgesia involves injecting local anesthetics or opioids into the epidural space surrounding the spinal cord, which provides effective pain relief with minimal systemic side effects. This method is particularly useful for thoracotomy patients as it allows for continuous pain management and reduces the need for systemic opioids, which can cause respiratory depression and other adverse effects. The epidural space can be targeted using a thoracic epidural catheter, which is inserted through the skin and advanced to the desired level.

**Why Each Wrong Option is Incorrect**
**Option A:** **Systemic Opioids** - While opioids can provide pain relief, they are associated with significant side effects, such as respiratory depression, nausea, and vomiting, which can be particularly problematic in thoracotomy patients who are at risk of respiratory compromise.

**Option B:** **Nerve Blocks** - Intercostal nerve blocks can provide some pain relief, but they are often ineffective in managing severe postoperative pain after thoracotomy. Additionally, the pain can be diffuse and may not be adequately addressed by a single nerve block.

**Option C:** **Gabapentin** - Gabapentin is an anticonvulsant that can be used as an adjunctive therapy for pain management, but it is not sufficient on its own to manage severe pain after thoracotomy.

**Clinical Pearl / High-Yield Fact**
Epidural analgesia is a useful technique for managing postoperative pain after thoracotomy, and it is associated with improved patient outcomes, including reduced morbidity and mortality.

**Correct Answer:** E. Epidural Analgesia