**Core Concept**
The extraperitoneal approach for left sympathectomy involves dissecting the sympathetic chain located on the left side of the vertebral bodies. This procedure requires careful identification and preservation of surrounding structures to avoid injury.

**Why the Correct Answer is Right**
During a left sympathectomy via an extraperitoneal approach, the surgeon must be aware of the proximity of the left renal vein to the sympathetic chain. The left renal vein is a short and horizontal vessel that crosses over the abdominal aorta and the left common iliac artery, making it susceptible to injury during the procedure. The left renal vein lies anterior to the sympathetic chain and is at risk of being injured during the dissection.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is not provided, so we cannot evaluate it.
**Option B:** This option is not provided, so we cannot evaluate it.
**Option C:** This option is not provided, so we cannot evaluate it.
**Option D:** This option is not provided, so we cannot evaluate it.

**Clinical Pearl / High-Yield Fact**
During extraperitoneal approaches for sympathectomy, it is essential to identify the left renal vein early in the procedure to avoid injury. The left renal vein is a key landmark for the sympathetic chain, and its preservation is crucial to prevent postoperative complications.

**Correct Answer:** D.