Neck dissection
Encyclopedia
The neck dissection is a surgical procedure
for control of neck lymph node
metastasis
from Squamous cell carcinoma
(SCC) and Merkel cell carcinoma
(MCC) of the head and neck. The aim of the procedure is to remove lymph nodes from one side of the neck into which cancer cells may have migrated. Metastasis of squamous cell carcinoma into the lymph nodes of the neck reduce survival and is the most important factor in the spread of the disease. The metastases may originate from SCC of the upper aerodigestive tract, including the oral cavity, tongue, nasopharynx
, oropharynx
, hypopharynx
, and larynx
, as well as the thyroid
, parotid and posterior scalp.
To describe the lymph nodes of the neck for neck dissection, the neck is divided into 6 areas called Levels. The levels are identified by Roman numeral, increasing towards the chest. A further Level VII to denote lymph node groups in the superior mediastinum
is no longer used. Instead, lymph nodes in other non-neck regions are referred to by the name of their specific nodal groups.
Region II, III, IV: nodes associated with the IJV; fibroadipose tissue located medial to the posterior border of SCM and lateral to the border of the sternohyoid.
NX: Regional lymph nodes cannot be assessed
N0: No regional lymph node metastasis
N1: Metastasis in a single ipsilateral lymph node, 3 cm or less in greatest dimension
N2a: Metastasis in a single ipsilateral lymph node more than 3 cm but not more than 6 cm in greatest dimension
N2b: Metastasis in multiple ipsilateral lymph nodes, none more than 6 cm in greatest dimension
N2c: Metastasis in bilateral or contralateral nodes, no more than 6 cm in greatest dimension
N3: Metastasis in a lymph node more than 6 cm in greatest dimension 2
The radical neck dissection is defined as removing all of the lymphatic tissue in regions I-V including removal of the spinal accessory nerve (SAN), sternocleidomastoid muscle (SCM), and internal jugular vein (IJV). It does not include removal of the suboccipital nodes, periparotid nodes except for infraparotid nodes located in the posterior aspect of the submandibular triangle, buccal nodes, retropharyngeal nodes, or paratracheal nodes. 4
Modified radical neck dissection (MRND) is defined as excision of all lymph nodes routinely removed by radical neck dissection with preservation of one or more nonlymphatic structures, i.e., SAN, IJV, SCM. 4 Medina subclassifies the MRND into types I-III; where type I MRND preserves the SAN, type II MRND preserves the SAN and IJV, and type III MRND preserves the SAN, IJV, and SCM. The type III MRND is also referred to as the "functional neck dissection" as popularized by Bocca, however in his classic description the submandibular gland is not excised. 5
Selective neck dissection is defined as any type of cervical lymphadenectomy where there is preservation of one or more lymph node groups removed by the radical neck dissection. There are four common subtypes, the first of which is the supraomohyoid neck dissection. This removes lymph tissue contained in regions I-III. The posterior limit of the dissection is marked by the cutaneous branches of the cervical plexus and the posterior border of the SCM. The inferior limit is the superior belly of the omohyoid muscle where it crosses the IJV. The second subtype, posterolateral neck dissection, refers to the removal of the suboccipital lymph nodes, retroauricular lymph nodes, levels II-IV, and level V. This procedure is used most often to remove nodal disease from cutaneous melanoma of the posterior scalp and neck. 4 Originally described by Rochlin in 1962, the SAN, SCM, and IJV were preserved. Medina suggests subclassification of the posteriolateral neck dissection to types I-III to mirror preservation of SAN, IJV, and SCM as in MRND. 5 The lateral neck dissection removes lymph tissue in levels II-IV. Anterior neck dissection is the last subtype of selective neck dissection and refers to the removal of lymph nodes surrounding the visceral structures of the anterior aspect of the neck previously defined as level VI.4
The last major subtype is the extended neck dissection defined literally as removal of one or more additional lymph node groups and/or nonlymphatic structures not encompassed by radical neck dissection, such as parapharyngeal, superior mediastinal, and paratracheal. In practice, any of the previous neck dissections may be extended to include other structures. With those definitions in place, the evolution and current indications of the various neck dissections shall be discussed
Surgery
Surgery is an ancient medical specialty that uses operative manual and instrumental techniques on a patient to investigate and/or treat a pathological condition such as disease or injury, or to help improve bodily function or appearance.An act of performing surgery may be called a surgical...
for control of neck lymph node
Lymph node
A lymph node is a small ball or an oval-shaped organ of the immune system, distributed widely throughout the body including the armpit and stomach/gut and linked by lymphatic vessels. Lymph nodes are garrisons of B, T, and other immune cells. Lymph nodes are found all through the body, and act as...
metastasis
Metastasis
Metastasis, or metastatic disease , is the spread of a disease from one organ or part to another non-adjacent organ or part. It was previously thought that only malignant tumor cells and infections have the capacity to metastasize; however, this is being reconsidered due to new research...
from Squamous cell carcinoma
Squamous cell carcinoma
Squamous cell carcinoma , occasionally rendered as "squamous-cell carcinoma", is a histologically distinct form of cancer. It arises from the uncontrolled multiplication of malignant cells deriving from epithelium, or showing particular cytological or tissue architectural characteristics of...
(SCC) and Merkel cell carcinoma
Merkel cell carcinoma
Merkel cell carcinoma Merkel cell carcinoma Merkel cell carcinoma (also known as a "Cutaneous apudoma," "Primary neuroendocrine carcinoma of the skin," "Primary small cell carcinoma of the skin," and "Trabecular carcinoma of the skin"...
(MCC) of the head and neck. The aim of the procedure is to remove lymph nodes from one side of the neck into which cancer cells may have migrated. Metastasis of squamous cell carcinoma into the lymph nodes of the neck reduce survival and is the most important factor in the spread of the disease. The metastases may originate from SCC of the upper aerodigestive tract, including the oral cavity, tongue, nasopharynx
Nasopharynx
The nasopharynx is the uppermost part of the pharynx. It extends from the base of the skull to the upper surface of the soft palate; it differs from the oral and laryngeal parts of the pharynx in that its cavity always remains patent .-Lateral:On its lateral wall is the pharyngeal ostium of the...
, oropharynx
Oropharynx
The Oropharynx reaches from the Uvula to the level of the hyoid bone.It opens anteriorly, through the isthmus faucium, into the mouth, while in its lateral wall, between the two palatine arches, is the palatine tonsil....
, hypopharynx
Hypopharynx
In human anatomy, the hypopharynx is the bottom part of the pharynx, and is the part of the throat that connects to the esophagus....
, and larynx
Larynx
The larynx , commonly called the voice box, is an organ in the neck of amphibians, reptiles and mammals involved in breathing, sound production, and protecting the trachea against food aspiration. It manipulates pitch and volume...
, as well as the thyroid
Thyroid
The thyroid gland or simply, the thyroid , in vertebrate anatomy, is one of the largest endocrine glands. The thyroid gland is found in the neck, below the thyroid cartilage...
, parotid and posterior scalp.
History of Neck Dissections
- 1888 - Jawdynski described en bloc resection with resection of carotid, internal jugular vein and sternocleidomastoid muscle.
- 1906 - George W. CrileGeorge Washington CrileGeorge Washington Crile was a significant American surgeon. Crile is now formally recognized as the first surgeon to have succeeded in a direct blood transfusion. He also contributed to other procedures, such as neck dissection. Crile designed a small haemostatic forceps which bears his name;...
of the Cleveland ClinicCleveland ClinicThe Cleveland Clinic is a multispecialty academic medical center located in Cleveland, Ohio, United States. The Cleveland Clinic is currently regarded as one of the top 4 hospitals in the United States as rated by U.S. News & World Report...
describes the radical neck dissection. The operation encompasses removal of all the lymph nodes on one side of the neck, and includes removal of the spinal accessory nerveAccessory nerveIn anatomy, the accessory nerve is a nerve that controls specific muscles of the shoulder and neck. As part of it was formerly believed to originate in the brain, it is considered a cranial nerve...
(SAN, or CN XI), internal jugular veinInternal jugular veinThe two internal jugular veins collect the blood from the brain, the superficial parts of the face, and the neck.-Path:On both sides and at the base of the brain, the inferior petrosal sinus and the sigmoid sinus join to form the internal jugular vein...
(IJV) and sternocleidomastoid muscleSternocleidomastoid muscleIn human anatomy, the sternocleidomastoid muscle , also known as sternomastoid and commonly abbreviated as SCM, is a paired muscle in the superficial layers of the anterior portion of the neck...
(SCM). - 1957 - Hayes Martin describes routine use of the radical neck dissection for control of neck metastases.
- 1967 - Oscar Suarez and E. Bocca describe a more conservative operation which preserves SAN, IJV and SCM.
- Last 3 decades - Further operations have been described to selectively remove the involved regional lymph groups.
Division of the Neck into Levels and Sublevels
Memorial Sloan-Kettering Cancer Center developed the lymph node regional definitions most widely used today.To describe the lymph nodes of the neck for neck dissection, the neck is divided into 6 areas called Levels. The levels are identified by Roman numeral, increasing towards the chest. A further Level VII to denote lymph node groups in the superior mediastinum
Mediastinum
The mediastinum is a non-delineated group of structures in the thorax, surrounded by loose connective tissue. It is the central compartment of the thoracic cavity...
is no longer used. Instead, lymph nodes in other non-neck regions are referred to by the name of their specific nodal groups.
- Region I: Submental and submandibular triangles. Ia is the submental triangle bound by the anterior bellies of the digastric and the mylohyoid. Ib is the triangle formed by the anterior and posterior bellies of the digastric and body of mandible.
Region II, III, IV: nodes associated with the IJV; fibroadipose tissue located medial to the posterior border of SCM and lateral to the border of the sternohyoid.
- Region II: upper third including the upper jugular and jugulodigastric nodes and the upper posterior cervical nodes. Region bound by the digastric muscle superiorly and the hyoid bone (clinical landmark), or the carotid bifurcation (surgical landmark) inferiorly. IIa contains nodes in the region anterior to the spinal accessory nerve and IIb posterior to the nerve.
- Region III: middle third jugular nodes extending from the carotid bifurcation superiorly to the cricothyroid notch (clinical landmark), or inferior edge of cricoid cartilage (radiological landmark), or omohyoid muscle (surgical landmark).
- Region IV: lower jugular nodes extending from the omohyoid muscle superiorly to the clavicle inferiorly.
- Region V: posterior triangle group of lymph nodes located along the lower half of the spinal accessory nerve and the transverse cervical artery. The supraclavicular nodes are also included in this group. The posterior boundary is the anterior border of the trapezius muscle, the anterior boundary is the posterior border of the sternocleidomastoid muscle, and the inferior boundary is the clavicle.
- Region VI: anterior compartment group comprises lymph nodes surrounding the midline visceral structures of the neck extending from the level of the hyoid bone superiorly to the suprasternal notch inferiorly. On each side, the lateral boundary is the medial border of the carotid sheath. Located within this compartment are the perithyroidal lymph nodes, paratracheal lymph nodes, lymph nodes along the recurrent laryngeal nerves, and precricoid lymph nodes. 4
Staging
The staging of head and neck cancer includes a classification for nodal disease. It is important to note the critical difference in size of nodes with break points at 3 and 6 cm. The staging system for head and neck malignancies considers all malignancies with palpable cervical adenopathy as Stage 3 or Stage 4, reflecting the grim prognostic implications of palpable nodal disease. 2 The most important prognostic indicator in patients with squamous carcinoma of the head and neck remains the status of the cervical lymph nodes. 3NX: Regional lymph nodes cannot be assessed
N0: No regional lymph node metastasis
N1: Metastasis in a single ipsilateral lymph node, 3 cm or less in greatest dimension
N2a: Metastasis in a single ipsilateral lymph node more than 3 cm but not more than 6 cm in greatest dimension
N2b: Metastasis in multiple ipsilateral lymph nodes, none more than 6 cm in greatest dimension
N2c: Metastasis in bilateral or contralateral nodes, no more than 6 cm in greatest dimension
N3: Metastasis in a lymph node more than 6 cm in greatest dimension 2
Classification of Neck Dissections
The 2001 revisions proposed by the American Head and Neck Society (AHNS) and the American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) are as follows.- Radical Neck Dissection (RND) - removal of all ipsilateral cervical lymph node groups from levels I through V, together with SAN, SCM and IJV.
- Modified Radical Neck Dissection (MRND) - removal of all lymph node groups routinely removed in a RND, but with preservation of one or more nonlymphatic structures (SAN, SCM and IJV).
- Selective Neck Dissection (SND) (together with the use of parentheses to denote the levels or sublevels removed) - cervical lymphadenectomyLymphadenectomyLymphadenectomy consists of the surgical removal of one or more groups of lymph nodes. It is almost always performed as part of the surgical management of cancer....
with preservation of one or more lymph node groups that are routinely removed in a RND. Thus for oral cavity cancers, SND (I-III) is commonly performed. For oropharyngeal, hypopharyngeal and laryngeal cancers, SND (II-IV) is the procedure of choice. - Extended Neck Dissection - This refers to removal of one or more additional lymph node groups or nonlymphatic structures, or both, not encompassed by the RND.
The radical neck dissection is defined as removing all of the lymphatic tissue in regions I-V including removal of the spinal accessory nerve (SAN), sternocleidomastoid muscle (SCM), and internal jugular vein (IJV). It does not include removal of the suboccipital nodes, periparotid nodes except for infraparotid nodes located in the posterior aspect of the submandibular triangle, buccal nodes, retropharyngeal nodes, or paratracheal nodes. 4
Modified radical neck dissection (MRND) is defined as excision of all lymph nodes routinely removed by radical neck dissection with preservation of one or more nonlymphatic structures, i.e., SAN, IJV, SCM. 4 Medina subclassifies the MRND into types I-III; where type I MRND preserves the SAN, type II MRND preserves the SAN and IJV, and type III MRND preserves the SAN, IJV, and SCM. The type III MRND is also referred to as the "functional neck dissection" as popularized by Bocca, however in his classic description the submandibular gland is not excised. 5
Selective neck dissection is defined as any type of cervical lymphadenectomy where there is preservation of one or more lymph node groups removed by the radical neck dissection. There are four common subtypes, the first of which is the supraomohyoid neck dissection. This removes lymph tissue contained in regions I-III. The posterior limit of the dissection is marked by the cutaneous branches of the cervical plexus and the posterior border of the SCM. The inferior limit is the superior belly of the omohyoid muscle where it crosses the IJV. The second subtype, posterolateral neck dissection, refers to the removal of the suboccipital lymph nodes, retroauricular lymph nodes, levels II-IV, and level V. This procedure is used most often to remove nodal disease from cutaneous melanoma of the posterior scalp and neck. 4 Originally described by Rochlin in 1962, the SAN, SCM, and IJV were preserved. Medina suggests subclassification of the posteriolateral neck dissection to types I-III to mirror preservation of SAN, IJV, and SCM as in MRND. 5 The lateral neck dissection removes lymph tissue in levels II-IV. Anterior neck dissection is the last subtype of selective neck dissection and refers to the removal of lymph nodes surrounding the visceral structures of the anterior aspect of the neck previously defined as level VI.4
The last major subtype is the extended neck dissection defined literally as removal of one or more additional lymph node groups and/or nonlymphatic structures not encompassed by radical neck dissection, such as parapharyngeal, superior mediastinal, and paratracheal. In practice, any of the previous neck dissections may be extended to include other structures. With those definitions in place, the evolution and current indications of the various neck dissections shall be discussed
External links
- Patient Information for neck dissection at Georgetown Univ. Hospital
- Neck dissection: an operation in evolution in World Journal of Surgical Oncology
- eMedicine: Head and Neck Cancer: Resection and Neck Dissection
- eMedicine: Radical Neck Dissection