# Neck Dissection > Neck dissection in FMGE Surgery: levels I-VI, radical versus modified radical and selective types, accessory nerve preservation and complications. - Canonical URL: https://prepelephant.com/topics/fmge/surgery/neck-dissection-fmge - Exam / course: FMGE · Subject: Surgery - Publisher: PrepElephant (https://prepelephant.com) — Prepared and reviewed by the PrepElephant Academic Review Team - First published: 2026-10-02 - Last updated: 2026-10-02 - How to cite: "Neck Dissection", PrepElephant, https://prepelephant.com/topics/fmge/surgery/neck-dissection-fmge ## Direct answer The radical neck dissection George Crile described in 1906 removed the lymphatic contents of levels I through V together with the sternocleidomastoid muscle, the internal jugular vein and the spinal accessory nerve — an oncologically sound operation whose price was shoulder drop, contour deformity and facial oedema. Modern practice has re-engineered it: the modified radical neck dissection clears the same five levels while preserving one or more of those three structures, and the selective neck dissection clears only the levels at risk from a given primary — supraomohyoid (levels I-III) for oral cavity cancers, lateral (II-IV) for oropharyngeal and laryngeal primaries — reserving radical dissection for bulky nodal disease that genuinely invades the accessory nerve or jugular vein. The nodal level roadmap (I submental/submandibular, II-IV jugular chains from skull base to clavicle, V posterior triangle, VI central paratracheal compartment) is the grammar of every head-and-neck cancer question, and elective dissection of a clinically negative neck is justified when the risk of occult nodal metastasis exceeds roughly 20 per cent. ## What you must remember - **Level map:** Ia submental, Ib submandibular; II upper jugular (skull base to hyoid), III mid-jugular (hyoid to cricoid), IV lower jugular (cricoid to clavicle); V posterior triangle (Va above, Vb below the accessory nerve); VI central compartment between carotids from hyoid to suprasternal notch; VII superior mediastinum. - **Radical neck dissection:** en bloc levels I-V plus sternocleidomastoid, internal jugular vein and spinal accessory nerve — the historical standard, now for extensive disease. - **Modified radical (MRND):** all five levels cleared with preservation of one or more of SCM, IJV or accessory nerve, divided into type I (nerve only), type II (nerve plus SCM), type III (all three). - **Selective neck dissection:** by primary site — supraomohyoid I-III for oral cavity; lateral jugular II-IV for larynx, hypopharynx and oropharynx; central compartment VI for thyroid and subglottic/tracheal tumours; posterolateral for scalp/nape lesions. - **When to dissect a clinically negative (N0) neck:** when occult metastasis risk exceeds about 20% — oral cavity and oropharyngeal cancers qualify; sentinel node biopsy is emerging for selected oral cavity lesions. - **Complications to quote:** shoulder syndrome from accessory nerve injury (painful abduction weakness beyond 90 degrees), chyle leak and lymphorrhoea (thoracic duct, left side), haematoma with airway compromise, marginal mandibular and hypoglossal nerve injury, and facial/cerebral oedema after bilateral internal jugular sacrifice. - **Bilateral necks:** oral cavity and midline tumours drain to both sides; when both internal jugular veins must be sacrificed, stage the procedures. - **Indian context:** oral cavity squamous carcinoma driven by tobacco and areca nut (gutkha) chewing makes neck dissection among the commonest major oncological operations in Indian head-neck practice; level Ib involvement with facial node disease is frequent in buccal malignancy. ## How to work through an operative plan A 52-year-old man with a left buccal mucosa squamous carcinoma (a gutkha chewer for 25 years) has a 3 cm ipsilateral level II node and no contralateral nodes. Staging CT confirms no distant disease. The surgical plan: wide excision of the primary with an ipsilateral modified radical neck dissection (clearing I-V for clinically node-positive disease, preserving the accessory nerve if uninvolved) and an elective contralateral supraomohyoid dissection, because oral cavity primaries drain bilaterally. Afterwards, shoulder physiotherapy protects the preserved accessory nerve. Contrast a clinically N0 T2 tongue tumour: elective supraomohyoid dissection alone is defensible. Contrast again a papillary thyroid carcinoma with central nodes: the operation is a total thyroidectomy with central compartment (level VI) dissection — no levels II-V needed. The primary site dictates the levels; the nodal burden dictates the extent; that double logic answers most neck-dissection questions. ## Where students slip Candidates mix up MRND and selective dissection definitions — MRND still clears all five levels; it only spares structures, whereas selective spares levels themselves. The second slip is shoulder syndrome attribution: it follows accessory nerve sacrifice or injury, not internal jugular ligation. Third, forgetting that level VI is not part of a standard lateral neck dissection and belongs to thyroid/central disease is a recurring matching error. ## Frequently asked questions ### What structures are sacrificed in a radical neck dissection? Lymphatic levels I-V en bloc with the sternocleidomastoid muscle, internal jugular vein and spinal accessory nerve — the operation modified versions seek to spare. ### How does a selective neck dissection differ from a modified radical one? Selective dissection clears only the nodal levels at statistical risk from the primary tumour, while modified radical clearance removes all five levels but preserves selected non-lymphatic structures. ### Which levels does an oral cavity cancer drain to first? Levels I-III (supraomohyoid), with level Ib particularly involved in buccal and lower-alveolar primaries — hence the supraomohyoid selective dissection. ### What is shoulder syndrome? Abduction weakness, pain and drooping of the shoulder after spinal accessory nerve sacrifice or injury during neck dissection, mitigated by physiotherapy and nerve preservation. ### What causes a chyle leak after neck dissection? Injury to the thoracic duct, classically on the left side (level IV), presenting as milky drain output managed by drainage, dietary fat modification, and re-exploration if high-output.