Overview of Neck Cancer Resection and Dissection
Head and neck cancer is among the top six most common types of cancer around the world. The severity of squamous cell carcinoma, a type of skin cancer, largely depends on the condition of the cervical lymph nodes, which are small, bean-shaped organs that produce and store cells that fight infection and disease. If the cancer has spread to these nodes, the chances of surviving for 5 years are halved in comparison with patients whose disease is still in its early stages. The American Cancer Society states that 40% of people suffering from squamous cell carcinoma in the mouth and throat area already have cancerous spread to the cervical lymph nodes when they’re diagnosed.
Because of this, managing the cervical lymph nodes is a crucial part of treating patients with squamous cell carcinoma. Having surgery to treat head and neck cancer is a significant procedure and can potentially have severe side effects. Not all patients may be suitable candidates for the surgery, and therefore, to avoid unsatisfactory results, it’s crucial to thoroughly assess each patient’s situation.
This assessment includes a pre-surgery heart and lung check-up on top of the usual cancer staging, a process which involves finding out how much cancer there is in the body and where it’s located. Though surgery might prove to be more successful in controlling the cancer locally, the overall survival rates with surgical and non-surgical treatments are quite similar for many head and neck cancers. Thus, doctors need to personalize treatments according to each patient’s needs, with a focus on maximizing their quality of life and functionality after the treatment. When cervical lymph nodes are to be removed as part of cancer treatment, the surgery is known as “neck dissection.” The specific surgical procedures are planned based on the potential spread of cancer from the primary tumor site.
Anatomy and Physiology of Neck Cancer Resection and Dissection
The classification of cervical lymph nodes (tiny bean-shaped organs that produce and store cells that fight infection and diseases) follows a system developed at Memorial Sloan-Kettering Cancer Center in the 1930s. This system organizes the lymph nodes on the side of the neck into five levels, from I to V. The central compartment nodes are in level VI, and those in the uppermost part of the area between the lungs are in level VII. Here are the levels and their boundaries:
1. Level I: Positioned in the area under the chin (level Ia) and below the lower jaw on both sides (level Ib).
– Upper Boundary: The lower border of the lower jaw
– Back Boundary: The back belly of the digastric muscle (a small muscle located under the jaw)
– Lower Boundary: The hyoid bone (a horseshoe-shaped bone in the neck)
2. Level II: Located along the side of the neck near the accessory nerve.
– Upper Boundary: The base of the skull
– Back Boundary: The back border of the sternocleidomastoid muscle (a muscle that runs down the side of the neck)
– Front Boundary: The outer limit of the sternohyoid muscle (a thin, narrow muscle that runs from the sternum to the hyoid bone)
– Lower Boundary: The hyoid bone
3. Level III: Located in the middle part of the neck.
– Upper Boundary: The hyoid bone
– Back Boundary: The back border of the sternocleidomastoid muscle
– Front Boundary: The outer limit of the sternohyoid muscle
– Lower Boundary: The cricothyroid membrane (a thin sheet of tissue between the thyroid cartilage and the cricoid cartilage)
4. Level IV: Located in the lower part of the neck.
– Upper Boundary: The cricothyroid membrane
– Back Boundary: The back border of the sternocleidomastoid muscle
– Front Boundary: The outer limit of the sternohyoid muscle
– Lower Boundary: The collarbone
5. Level V: Found in the back part of the neck.
– Back Boundary: The front border of the trapezius muscle (a large muscle that covers the back of the neck and upper spine)
– Front Boundary: The back border of the sternocleidomastoid muscle
– Lower Boundary: The collarbone
6. Level VI: Located centrally in the neck.
– Upper Boundary: The hyoid bone
– Lower Boundary: The area above the breastbone
– Side Boundaries: The medial (closest to the midline of the body) border of the carotid sheath (a layer of connective tissue carrying vessels and nerves) on each side
7. Level VII: Located in the upper part of the area between the lungs.
– Upper Boundary: The area above the breastbone
– Lower Boundary: The innominate artery (a large artery in the chest)
Why do People Need Neck Cancer Resection and Dissection
Understanding Neck Surgery
It’s crucial to know a bit about the history and types of neck surgery before we delve into when it’s needed and how it’s done. The first person who successfully performed a curative neck surgery for neck tumors was George Washington Crile from the Cleveland Clinic. In the early 1900s, he did various neck surgeries and described a type of operation known as the radical neck dissection (RND). This operation laid the foundation for all neck surgeries done since then.
However, this type of surgery can result in a change in physical appearance and issues with shoulder movement. This is due to the removal of the sternocleidomastoid muscle, internal jugular vein, and the tail of the parotid gland and damage to the accessory nerve. To address these issues, Argentinian surgeon Oswaldo Suarez proposed a less invasive form of surgery in 1963, known as the modified radical neck dissection (MRND). This technique removes all affected lymph nodes from the neck, while preserving the nerve, muscle, and vein associated with shoulder function.
There are different types of neck surgery, which are used depending on the extent and location of the disease:
1. Radical Neck Dissection (RND): This is when lymph nodes, a muscle (sternocleidomastoid), a vein (internal jugular), and a nerve (spinal accessory) from one side of the neck are removed. It’s mainly done when there’s a large cancerous growth in the neck that has invaded surrounding tissues.
2. Modified Radical Neck Dissection Type I (MRND-I): In this surgery, the muscle and vein, along with lymph nodes, are removed while the nerve is preserved. This is usually performed when cancer has invaded the muscle and vein but not the nerve.
3. Modified Radical Neck Dissection Type II (MRND-II): This involves removing lymph nodes and the muscle while preserving the vein and nerve. This is typically done when the disease has spread to the muscle but not to the vein or nerve.
4. Modified Radical Neck Dissection Type III (MRND-III): In this case, only the lymph nodes are removed while the muscle, vein, and nerve are preserved. It’s usually performed when cancer has only slightly spread outside the lymph nodes and not to the other structures.
In addition to the types of surgeries, the specific surgery required depends on the disease’s location and severity:
1. Supraomohyoid Neck Dissection (SOHD): Involves removing lymph nodes from the upper neck while preserving the vein, muscle, and nerve. This is done in patients with certain types of cancers like squamous cell carcinoma or malignant melanoma.
2. Selective Neck Dissection (SND): A procedure that involves removing lymph nodes without taking out the vein, muscle, and nerve. It’s usually recommended when cancer is in the lateral part of the tongue, oral cavity, or floor of the mouth, or when one specific node is affected.
3. Lateral Neck Dissection: This involves removing lymph nodes from various levels in the neck while preserving the vein, muscle, and nerve. It’s indicated in cases of cancer of the voice box, lower throat, thyroid, or skin cancer with a positive lymph node test.
4. Postero-lateral Neck Dissection: This procedure includes removing lymph nodes from the back and sides of the neck and behind the ear while preserving the vein, muscle, and nerve. It’s typically done in patients with a certain stage of skin cancer.
5. Modified Radical Neck Dissection: As mentioned, these surgical procedures are commonly used to treat thyroid cancer or oral and throat cancers with positive nodes in the lateral neck and limited spread outside the nodes.
Each surgical procedure and its corresponding indications are designed to tailor the treatment to the specific requirements of each patient, balancing the removal of the disease with the preservation of function and quality of life.
When a Person Should Avoid Neck Cancer Resection and Dissection
There are a few situations where a person may not be suitable for a neck dissection, which is a medical procedure primarily used to treat cancer, beyond those cases where they can’t tolerate being put to sleep (general anesthesia) for the operation or the process of removing the targeted area (resection). The only exception is when the disease has progressed to the point where it can’t be effectively cut out or treated (unresectable disease). Some other situations where a neck dissection might not be recommended include:
1. Having severe heart-lung conditions (severe cardiopulmonary disease), or Chronic Obstructive Pulmonary Disease (COPD), which makes breathing difficult, with a poor state of health (functional status).
2. Preliminary scans show that the tumor has deeply spread into certain areas of the neck such as the area in front of the backbone (prevertebral space), the scalene muscles, levator scapula muscle, phrenic nerve, and the bundle of nerves in the neck that control arm movement (brachial plexus). Patients in such cases may not be suitable.
3. Having a primary tumor that cannot be managed effectively.
4. Metastatic disease which means the cancer has spread to distant parts of the body.
5. The tumor has encased (completely surrounded) the major artery in the neck (carotid artery). This is often referred to as ‘unresectable disease’ because even if the tumor can technically be removed and the artery restored, this won’t necessarily improve the chances of surviving or controlling the disease locally.
In addition, a distinct situation where neck dissection is definitely discouraged is when the cancerous mass is fixed in the deep neck muscles, the tissue that covers the muscles in front of the backbone (prevertebral fascia), or has spread to the base of the skull. This is also termed as ‘unresectable disease’.
Equipment used for Neck Cancer Resection and Dissection
For any routine surgery involving the head and neck, all the necessary tools should be included in the surgeon’s toolkit. The surgeon might choose to use some additional, special tools based on their personal preference and the specific requirements of the operation.
These special tools could include McCabe nerve dissectors (used for delicate procedures on the nerves), nerve hooks (used to move nerves out of the way during surgery), harmonic scalpels (a special type of scalpel that cuts using high-frequency vibrations), 0.9mm forceps (small clamping tools used to hold or manipulate tissues), Munion right-angle clamps (another type of clamp used to hold tissue or vessels), among other instruments.
Who is needed to perform Neck Cancer Resection and Dissection ?
The surgical team is made up of several key people. These include a surgeon, who is the main doctor doing the operation. The surgeon is supported by an assistant surgeon. This person could be another trained surgeon, a medical student (also called a resident or registrar), or a professional specially trained to assist in surgeries. A scrub nurse is also part of the team, and this is a nurse who helps the surgeons in the operating room. A circulating nurse helps out too, and their job is to move around and make sure everything is running smoothly in the operating area. Lastly, an anesthetist is a medical professional who ensures you are properly sedated and pain-free during the operation. All these people work together to make sure your surgery goes as smoothly as possible.
Preparing for Neck Cancer Resection and Dissection
Before a surgery to remove lymph nodes in the neck (called neck dissection), there are not many specific steps that a patient needs to take. The doctor will plan where the surgical cuts (incisions) will be made, particularly if they are also removing a tumor at the same time. These incisions also need to consider any additional surgery needed to repair the area after the tumor has been removed.
Now for the surgery itself, you will need general anaesthesia through a tube inserted into your windpipe (endotracheal anaesthesia), which means you’ll be asleep and will not feel any pain. On this matter, the use of drugs to cause muscle relaxation (paralytic agents), needs to be discussed between the surgeon and the anesthetist, the doctor who administers the anesthesia.
During the operation, you will be laying down flat (in the supine position) with your head elevated at about a 30-degree angle. To make it easier for the surgeon to access your neck, a rolled-up towel or blanket (shoulder roll) might be put under your shoulders to stretch (hyper-extend) your neck, and your head will be turned to the side opposite to where the surgery is being done.
How is Neck Cancer Resection and Dissection performed
The doctor makes an incision, or cut, in a natural neck crease. This incision is used to reach the affected area in the neck. In the past, doctors would make multiple incisions, but a single incision is now more commonly used. If the disease has spread to the back of the neck, multiple incisions might still be necessary. In these cases, care is taken to avoid the carotid artery, one of the major blood vessels in the neck.
Next, the doctor deepens the incision through the fat under your skin and then through a muscle in your neck called the platysma. The doctor raises a flap of skin and muscle to expose the underlying tissues. During this part of the procedure, the doctor identifies and protects important nerves and blood vessels in your neck. This avoids causing any temporary damage to the nerves.
The next step of the surgery involves removing fatty tissue from the area under your chin. The tissue is retracted, or pulled back, to expose important structures in the lower part of the neck. These include nerves and blood vessels that need to be preserved. Some nerves and blood vessels may be divided or cut off at this point, depending on the needs of the reconstructive surgeon.
The doctor then moves on to dissect, or separate, tissues at the sides and bottom of your neck. The muscles are gently lifted to expose nerves and other structures. Care is taken to avoid damaging these structures. During these steps of the procedure, the doctor looks for any disease that has spread to these areas of the neck.
The doctor then moves towards the center of the neck. The dissection reveals the vagus nerve, the common carotid artery, and the internal jugular vein. The doctor takes care to protect these and move cautiously in case there’s a thoracic duct, or a large vessel carrying lymph fluid, in the area.
Finally, the doctor closes the incision. The layers include the platysma muscle and the skin. Drains, or small tubes, are left in place to remove fluid from the wound. These drains are placed in particular spots, avoiding pressure on important structures like blood vessels and nerves.
Possible Complications of Neck Cancer Resection and Dissection
Here’s what can happen after neck surgery:
1. You might get an infection. This is a common risk with all surgeries.
2. There might be an air leak, meaning air can escape from where the surgery took place, which can potentially lead to other issues.
3. You could experience bleeding after your operation. This usually happens if a blood vessel was accidentally damaged during the procedure.
4. Some people might develop a chylous fistula. This is when lymphatic fluid leaks and starts to build up under your skin or in your wound. This happens to between 1% to 2.5% of people who have this type of surgery. The way doctors deal with this complication depends on how quickly it happens after surgery, how much fluid is coming out each day, and whether or not the fluid is accumulating under your skin.
5. Having the internal jugular veins in both sides of your neck operated on at the same time can lead to complications. This can cause swelling in the face or brain, vision loss, and low oxygen levels in your blood. These are severe complications and need immediate attention.
6. There’s a significant risk of carotid artery rupture—an event where one of the main blood vessels in your neck bursts. This can be life-threatening. This is why it’s crucial for the surgical incisions to be carefully planned to avoid exposing the carotid artery. If it does get exposed, it needs to be covered immediately with well-supplied tissue to prevent rupture.
7. Surgery on the neck sometimes involves removing a nerve that helps control a muscle in your shoulder. This can lead to problems with shoulder movement and can cause your shoulder to appear deformed. It can also lead to shoulder pain and weakness. These are common problems with neck surgery and can be reduced by performing the procedure in a particular way.
What Else Should I Know About Neck Cancer Resection and Dissection ?
Surgeons who treat conditions in the head and neck, all over the world, use various surgical procedures to remove lymph nodes in the neck for patients with head and neck cancers. This is done in different ways as the techniques and methods continue to improve and advance. The need for removing lymph nodes in the neck for different types of diseases, which include a variety of cancers such as skin cancer, squamous cell carcinoma, and thyroid cancer, is changing and progressing rather quickly. Doctors constantly modify their approach based on their understanding and development in the field to provide the best treatment for their patients.
