Study Purpose: This study is testing a skin patch called Qutenza (8% capsaicin) and comparing it to a low-dose capsaicin patch (0.04%) to see how well they work for treating nerve pain after surgery, called postsurgical neuropathic pain (PSNP). Capsaicin is a natural ingredient found in chili peppers that can help relieve pain by numbing the nerves.

The study is double-blind, which means neither the participants nor the researchers know who is getting which treatment. It's a Phase III trial, meaning it's in the final stages of testing the treatment's effectiveness and safety.

• Participation: You must be 18 or older and have had nerve pain for at least 6 months after surgery.
• Study Length: You will need to attend multiple visits and keep a pain diary.
• Risks: Possible side effects include skin irritation from the patch. You must not have certain health conditions.

Before joining, you must agree to follow study rules, including using birth control if needed. You can't join if you've used Qutenza before or have other certain health issues.