Which of the following structure is preserved in Type I Modified radical neck dissection?
💡 Explanation
## **Core Concept**
Type I Modified Radical Neck Dissection (MRND) is a surgical procedure used in the management of head and neck cancers. It involves the removal of lymph nodes from the neck while preserving certain vital structures. The main goal is to remove the lymph nodes that are at risk of containing cancer while sparing important nerves and other tissues.
## **Why the Correct Answer is Right**
In a Type I MRND, the **sternocleidomastoid muscle (SCM)**, **internal jugular vein (IJV)**, and **spinal accessory nerve (SAN)** are preserved. This procedure is less extensive than a radical neck dissection, which removes these structures. The SCM is a key muscle for neck rotation and is preserved to maintain neck function. The IJV is crucial for venous drainage of the head and neck, and its preservation helps prevent venous congestion. The SAN is important for shoulder function, particularly for the trapezius muscle.
## **Why Each Wrong Option is Incorrect**
- **Option A:** Incorrect because the SCM is actually preserved in Type I MRND.
- **Option B:** Incorrect as the IJV is also preserved.
- **Option D:** Incorrect because the SAN is preserved.
## **Clinical Pearl / High-Yield Fact**
A key point to remember is that in head and neck cancer surgeries, the goal is often to balance oncologic efficacy with functional preservation. Type I MRND is chosen when there's a need to minimize the extent of surgery while still addressing potential microscopic disease in the lymph nodes.