Table of Contents
Introduction:
Patients with low nodal stage disease and those with clinically negative nodal disease, which has a high risk of micrometastasis, are frequently advised to use it. The diversity in lymph node levels and sublevels associated with these names was not reflected in the traditional terminology used for the numerous types of selective neck dissection, such as suprahyoid neck dissection, anterolateral neck dissection, and central compartment dissection, among others. The American Academy of Otolaryngology-Head and Neck Surgery advised surgeons to refer to their technique as "selective neck dissection," or "SND," in 2002 to promote standardization and prevent misunderstanding.
A unique clinical condition could emerge from the removal of each functioning structure. After SAN sacrifice, the trapezius muscle denervation frequently leads to "shoulder syndrome," characterized by shoulder pain, a winged scapula, and weak abduction. This condition is caused by adhesive capsulitis. Even when patients start shoulder rehabilitation exercises as soon as possible after surgery, this syndrome hurts their quality of life. RND modifications were specifically designed to prevent the SAN from being lost while still eliminating metastasis-prone nodes. According to clinical findings, shoulder syndrome is less likely if the SAN is spared and patients have reduced discomfort, functional impairment, and improvements in strength and range of motion.
What Is the Neck Dissection?
The surgical treatment used to treat metastatic cervical lymphadenopathy is neck dissection or cervical lymphadenectomy. Different neck dissection techniques differ depending on which structures are removed. The article reflects the American Head and Neck Society and the American Academy of Otolaryngology's 2001 head and neck surgery classifications.
Classification:
Radical Neck Dissection:
The historical benchmark used to compare and define future methods is radical neck dissection. During this procedure, the submandibular gland and all ipsilateral cervical lymph nodes from levels I through V are removed.
Moreover, three crucial extranodal structures are eliminated:
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Internal jugular vein (IJV).
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Sternocleidomastoid muscle.
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Spinal accessory nerve.
Modified Radical Neck Dissection:
Similar to traditional radical neck dissection, modified radical neck dissection entails removing cervical nodes, levels I through V, while leaving one or more important extranodal structures intact (spinal accessory nerve, sternocleidomastoid muscle, and internal jugular vein). Although the structures spared in a modified radical neck dissection were previously classified by kinds (I through III), it is advisable to define them specifically due to variations in practice (e.g., modified radical neck dissection with preservation of the spinal accessory nerve).
Selective Neck Dissection:
Some cervical lymph node groups are removed during selective neck dissection (SND), but not all of them are in the radical neck dissection.
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Levels I–III of the supraomohyoid.
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Levels II-IV of the expanded supraomohyoid (anterolateral).
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Levels II–V of the posterolateral.
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Suboccipital; levels II–IV of the postauricular lateral (jugular).
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Anterior central: level VI.
A precise description with "SND" and brackets indicating the levels deleted, such as SND (I–IV), was preferred to the named subtypes in the 2001 classification due to changing procedures. Based on anticipated patterns of metastatic spread from a certain source site, different cervical lymph node groupings and levels are usually removed:
Mouth Cavity: Stages I–III:
Level IV oropharynx, hypopharynx, and larynx: levels II-IV, except level IIB in certain cases of laryngeal or hypopharyngeal cancer, plus retropharyngeal nodes if the primary lesion involves the pharyngeal wall, plus level VI if the primary lesion extends below the glottis level, plus superior mediastinal nodes if the primary lesion extends below the suprasternal notch level thyroid: these are additional procedures that some surgeons perform. The skin of the preauricular, anterior scalp, and temporal region: levels II–III, level VA, parotid, facial, external jugular; the skin of the anterior and lateral face: levels I–III, parotid, facial level VI skin of the posterior scalp and upper neck: levels II–V, suboccipital, postauricular
If the initial lesion crosses the midline, dissections are carried out bilaterally.
Extended Radical Neck Dissection:
Similar to classical radical neck dissection, extended radical neck dissection involves the removal of levels I through V along with important non-nodal structures such as the sternocleidomastoid muscle, internal jugular vein, and spinal accessory nerve. However, it also involves the removal of one or more additional lymph node groups and/or non-lymphatic structures.
Among these nodal groupings are:
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Subcortical nodes.
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Nodes retropharyngeal.
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Nodes of parotids.
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Level VI facial nodes (such as buccinator nodes) and peri thyroidal, paratracheal, and Delphian nodes.
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Superior nodes of the mediastinal.
Among the potential non-lymphatic structures are:
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Paraspinal muscles.
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Vagus nerve.
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Hypoglossal nerve.
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Carotid artery.
Where Is Selective Neck Dissection Used?
When a patient with head and neck cancer has cervical lymph nodes that are suspected of harboring metastatic disease, the procedure is done with two objectives in mind: first, to ascertain the disease's stage at the time of presentation, and second, to achieve locoregional control over the nodal metastases. Up until recently, the most common procedures used to control local nodal illness were the RND and the MND. Regarding the preferred surgical approach, head and neck surgeons have been deeply divided since the early 1980s. According to some theories, the purpose of neck dissection is to remove the fibroadipose tissue in which the cervical nodes are embedded. Muscles, veins, and nerves are removed because they are near the nodal groups and for no other reason. It made oncologic sense to construct a method that spares the functionally crucial structures (SAN, SCM muscle, and IJV), and the MND was born.
The two comprehensive surgical procedures, the RND and the MND, are the primary techniques used for regional control of nodal metastatic illness in the past. The RND involved removing the IJV, SAN, SCM muscle, fibro adipose tissue around the nodes, and level I–V nodes. In addition, when level I nodes are removed, the submandibular gland is frequently resected. A variant of the RND, the MND maintains one or more of the nonlymphatic or functional components, such as the IJV, SAN, or SCM muscle.
Conclusion:
SND has gained popularity as a surgical technique for the targeted treatment of head and neck cancer metastases, whether they are known or unknown, while maintaining functional anatomy. The results of the postoperative imaging confirm the selected operation. Pericarotid and deep cervical fibro adipose tissue are nearly invariably lost. There may be atrophy or asymmetry in the SCM, even with SAN preservation. Atrophy of the infrahyoid strap muscles is another frequent occurrence. The radiologist should observe the patency of the ipsilateral IJV since vein thrombosis may happen. Because the contralateral IJV needs to be preserved, this could have an impact on subsequent surgeries.
