The document discusses the classification and techniques of neck dissection for cervical lymph node metastasis. It describes the different types of neck dissection including radical neck dissection (RND), modified radical neck dissection (MRND), and selective neck dissection (SND). It outlines the lymph node levels and boundaries involved in each procedure. Key factors in determining the appropriate procedure include the primary tumor site and extent of lymph node involvement.

2. Crile in 1906 introduced RND and is followed by Martin as a the classical procedure for the management of cervical lymph node metastasis Recently changes in classification and indication led to inconsistency N 0 in recent studies may require selective RND to reduce morbidity

3. N X : Regional lymph nodes can not be assessed N 0 : No regional lymph node metastasis N 1 : Metastasis in a single ipsilateral lymph nodes, 3 cm or less in greatest dimension N 2 : N 2a : Metastasis in a single epsilateral lymph nodes, more than 3 cm but less than 6 cm

4. N 2b : Metastasis in multiple ipsilateral lymph nodes, not more than 6 cm N 2c : Metastasis in bilateral or contralateral nodes not more than 6 cm in diameter N 3 : Metastasis in lymph nodes more than 6 cm in in greatest diameter Meyers & Eugene: Operative Otolaryngology. 1997

5. Region I: Submental and submandibular triangle I a : Submental triangle: Bounded by the anterior belly of digastric and the mylohyoid muscle deep I b : Submandibular triangle: Formed by the anterior and posterior belly of the digastric muscle and the body of the mandible Memorial Sloan-kettering Cancer center

6. Region II – IV: Lymph nodes are associated with the Internal Jugular Vein (IJV) within the fibroadipose tissues that extend from the posterior border of sternocledo-mastoid muscle (SCM) medial to lateral border of the sternohyoid muscle Memorial Sloan-kettering Cancer center

7. Region II: Upper third including upper jugular, jugulodigastric and upper posterior cervical nodes Bounded by the digastric muscle superiorly and the hyoid bone or carotid bifurcation inferiorly IIa: nodes anterior to Spinal Accessory Nerve (SAN) IIb: nodes posterior to Spinal Accessory Nerve (SAN) Memorial Sloan-kettering Cancer center

8. Region III: Middle third jugular nodes from the carotid bifurcation to cricothyroid notch or omohyoid muscle Region IV: Lower third jugular nodes from omohyoid muscle superiorly to the clavicle inferiorly Memorial Sloan-kettering Cancer center

9. Region V: Lymph nodes of the posterior triangle along the lower half of the SAN and the transverse cervical artery Bounded by the anterior border of the trapezius posteriorly, the posterior border of SCM anteriorly and the clavicle inferiorly Memorial Sloan-kettering Cancer center

10. Region VI: Anterior compartment, lymph nodes surrounding the midline visceral structures that extend from the hyoid bone superiorly to the suprasternal notch inferiorly The lateral boundary is the medial border of the carotid sheath Perithyroid, paratracheal, and lymph nodes around the recurrent laryngeal nerve Memorial Sloan-kettering Cancer center

11. The RND is classified according to the Academy’s Committee for Head & Neck Surgery & Oncology into four major type : Radical Neck Dissection (RND) Modified Radical Neck Dissection (MRND) Selective Neck Dissection (SND) Supraomohyoid Posterolateral Lateral Anterior Extended Radical Neck Dissection (ERND)

12. Radical neck Dissection: Removing all lymphatic tissues in regions I - V and include removal of SAN, SCM and IJV Modified radical neck dissection: Excision of all lymph nodes removed with RND with preservation of one or more non-lymphatic structures, SAN, SCM and/or IJV Subtype I: Preserve SAN Subtype II: Preserve SAN & SJV Subtype III: preserve SAN, SJV and SCM Known as Functional neck dissection (Bocca)

13. Selective Neck dissection: Any type of cervical lymphadenectomy with preservation of one or more lymph node groups Four subtype: Supraomohyoid neck dissection Posterolateral neck dissection Lateral neck dissection Anterior neck dissection

14. Supraomohyoid neck dissection: Removal of lymph nodes in regions I –III The posterior limit is the cutaneous branches of the cervical plexus and posterior border of SCM The inferior limit is the superior belly of the omohyoid where it cross IJN Posterolateral neck dissection Removal of suboccipital, retroauricular, levels II – V and level V Subtyped I – III depending on the preservation of SAN, IJV and /or SCM Medina

15. Lateral neck dissection: Remove lymph nodes in levels II – IV Anterior neck dissection: Require the removal of the lymph nodes surrounding the visceral structure in the anterior aspect of the neck, level VI Superior limit, hyoid bone Inferior limit, suprasternal notch Laterally, the carotid sheath

16. Extended neck dissection: Any previous dissection and including one or more additional lymph node groups and/or non-lymphatic tissues

17. General nodal metastasis produce the following fact: The most important factor in prognosis of SCC of the upper aero-digestive tract is the status of cervical lymph nodes Cure rate drops 50% with involvement of the regional lymph nodes

18. Radical neck dissection was believed by Martin to be the only method to control cervical lymphadenectomy Anderson found that preservation of SAN did not change the survival or tumor control in the neck Actual 5-year survival and neck failure rate is: RND: 63% and 12 % MRND: 71% and 12%

19. Radical Neck Dissection Multiple clinically obvious cervical lymph node metastasis particularly of posterior triangle and closely related to SAN Large metastatic tumor mass or multiple matted in upper part of the neck Tumor should not be dissected to preserve Structures

20. Modified radical neck dissection MRND Type I: Clinically obvious neck lymph nodes metastasis and SAN not involved by tumor Intraoperative decision just like preservation of the facial nerve in parotid surgery

21. MRND Type II: Rarely planned Intra-operative decision for tumor found adherent to SCM but away from SAN & IJV MRND Type III: Depend on the autopsy reports Lymph nodes were in the fibrofatty and do not share the same adventitia with blood vessels They are not found within the aponeurosis or glandular capsule of the submandibular “Functional neck dissection”

22. MRND Type III: For treatment of N 0 neck nodes Indicated for N 1 mobile nodes and not greater than 2.5 – 3.0 cm Contra-indicated in the presence of node fixation Result is difficult to interpret because of the use of radiation therapy

23. Selective/elective neck dissection: For treatment of N 0 neck nodes For N+ nodes when combined with radiotherapy Adjuvant radiotherapy for patient with 2 – 4 positive nodes or extra-capsular spread Supraomohyoid is indicated for SCC of oral cavity with N 0 and N 1 with palpable mobile nodes less than 3 cm and located in level I and II Upgrade intra-operatively following positive frozen section

24. Observe Radiation therapy Elective neck dissection Low morbidity Staging neck for possible extended surgery Need for post-operative radiotherapy

25. Rate of occult metastasis in clinically negative nodes is 20 – 30% using clinical and radiographic findings Ct scan combined with physical exam decreased the rate of occult metastasis to 12% This suggested lowering of the criteria for elective neck dissection Friedman et al Laryngoscope 100; 54 – 59: 1990

26. Anatomic studies showed that lymphatic drainage from the mucosal surfaces follow a constant and predictable route Lymph flow from SA chain to the jugular chain is unilateral Shah. Ann Surg Oncol 1(6); 521-532: 1994

27. Shah, in his study produced a compelling evidence of predictable nodal metastasis from SCC from upper aerodigastive tract He found a specific pattern for nodal spread by location of primary N O in patients with oral cavity SCC: 7/1119 (3.5%) had nodal involvement outside supraomohyoid dissection 3 (1.5%) had isolated involvement outside level I - III Friedman Laryngoscope 100; 54-59: 1990

28. N + nodes in patients with oral SCC: 50/246 had nodal metastasis outside level IV 10/246 had metastasis in level V He examined nodal involvement in patients with nasopharynx and other upper parts of the aerodigastive tract Conclusion: SCC of the oral cavity: Level I, II and III are at risk SCC nasopharynx and larynx Level II, III and IV are at risk Shah Amer J Surg 160; 405-409: 1990 Shah Cancer July 1 ; 109-113: 1990

29. Byers stated that SND combined with postoperative radiotherapy in selected patients with oral cavity SCC was adequate treatment with similar recurrence rate as those treated with MRND III Spiro reported 12% with supraomohyoid dissection in N1 nodes but not all of them received radiotherapy Byers Head Neck Surg; Jan-Feb; 160-167: 1988

30. A good option for N0 neck Not a suitable option for N+ neck Is used N+ neck when combined with radiotherapy Intra-operative frozen section evaluation is needed to confirm in cases of intraoperative palpable nodes

31. Skin: Blood supply: Descending branches: The facial The submental Occipital Ascending branches Transverse cervical Suprascapular The branches perforate the platysma muscle, anastomose to form superficial vertically-directed network of vessels Skin incision is superiorly based apron-like incision from mastoid to mentum or to contralateral mastoid

32. Platysma muscle: Wide, quadrangular sheet-like muscle Run obliquely from the upper part of the chest to lower face Skin flap is raised immediately deep to the muscle The posterior border is over or just anterior to IJV and great auricular nerve Does not cover the inferior part of the anterior triangle and the posterolateral neck

33. Sternocleidomastoid muscle: SCM Differentiated from the platysma by the direction of its fibres Crossed by the IJV and the great auricular nerve from inferior to posterior deep to platysma The posterior border represent the posterior boundary of nodes level II - IV

34. Marginal Mandibular nerve: MMN Located 1 cm in front of and below the angle of the mandible Deep to the superficial layer of the deep cervical fascia Superficial to adventitia of the anterior facial vein

35. Spinal Accessory nerve: SAN Emerge from the jugular foramen medial to the digastric and stylohyoid muscles and lateral and posterior to IJV (30% medial to the vein and in 3 -5% split the nerve) It passes obliquely downward and backward to reach the medial surface of the SCM near the junction of its superior and middle thirds, Erb’s point

36. Trapezius muscle: Its anterior border is the posterior boundary of level V Difficult to identify because of its superficial position Dissect superficial to the fascia in order to preserve the cervical nerves

37. Digastric Muscle ; Posterior belly: Originate from a groove in the mastoid process, digastric ridge The marginal mandibular nerve lie superficial The external and internal carotid artery, hypoglossal and 11 th cranial nerves and the IJV lie medial

38. Omohyoid muscle: Made of two bellies, and is the anatomic separation of nodal levels III and IV The posterior belly is superficial to the brachial plexus, phrenic nerve and transverse cervical artery and vein The anterior belly is superficial to the IJV

39. Brachial Plexus & Phrenic nerve: The plexus exit between the anterior and middle scalene muscles, pass inferiorly deep to the clavicle under the posterior belly of the omohyoid The phrenic nerve lie on top of the anterior scalene muscle and receive it is cervical supply from C3 – C5

40. Thoracic duct: Located in the lower let neck posterior to the jugular vein and anterior to phrenic nerve and transverse cervical artery Have a very thin wall and should be handled gently to avoid avulsion or tear leading to chyle leak

41. Exit via the hypoglossal canal near the jugular foramen Passes deep to the IJV and over the ICA and ECA and then deep and inferior to the digastric muscle and enveloped by a venous plexus, the ranine veins Pass deep to the fascia of the floor of the submandibular triangle before entering the tongue

42. Unified classification is relatively new Indication and the type of ND, specially for N0, is controversial The following surgical outline was suggested: SCC oral cavity anterior to circumvalate papilla Supraomohyoid SCC Oropharynx, larynx and hypopharynx level I- IV or level II-V SCC with N+ nodes RND SCC with 2-4 positive nodes or extracapsular spread RND and adjuvant therapy Shah Cancer July 1;109-113: 1990