This document provides an overview of neck anatomy and neck dissection procedures. It describes the boundaries and contents of the neck regions. It then discusses the different types of neck dissections including radical neck dissection, modified radical neck dissection, and selective neck dissections. Key structures such as lymph nodes, muscles, nerves and vessels are identified. Surgical considerations and indications for different procedures are also outlined.

1. NECK DISSECTION
Dr. Bikram B. Karki
PG – ENT HNS

2. NECK
• Superior border
anteriorly : mandible with deep limits of FOM
posteriorly : skull base
• Inferior limits
by upper aspect of first rib and
first thoracic vertebrae.

3. FASCIAL LAYERS
• Superficial cervical fascia
• Deep cervical fascia
• Investing or superficial layer
• Middle layer - Muscular compartment
- Visceral compartment
• Deep layer

4. SUPERFICIAL NECK MUSCLES
• Platysma
• Surgical considerations
• Absent in midline of neck
• Increases blood supply to skin flaps
• Fibers run in an opposite direction to SCM

5. • Sternocleidomastoid
• Surgical considerations
• divides neck into
anterior and posterior triangles
• LN 2, 3, 4 lies deep to it

6. • Trapezius muscle
• Surgical consideration
• Posterior limit of level V neck dissection
• Denervation results in shoulder drop and winged
scapula

7. SUPRAHYOID AND INFRA HYOID MUSCLE
• Suprahyoid muscle
• Digastric
• Stylohyoid
• Mylohyoid
• Geniohyoid
• hyoglossus

8. • Digastric muscle :
• Surgical considerations
• Anterior belly :
• Landmark for identification of mylohyoid
for dissection of submandibular
triangle
• Posterior belly
• Landmark for depth of FN as it exits
stylomastoid foramen

9. • Infrahyoid muscle
• Sternohyoid
• Sternothyroid
• Thyrohyoid
• omohyoid

10. • Omohyoid muscle:
• Surgical considerations
• Absent in 10% of individuals
• Landmark demarcating level III from
IV
• 2 bellies joind by flat tendon at
point
where muscle pass superficial to IJV

11. TRIANGLES OF NECK

12. • Submental triangle
• Single midline triangle
• Contents
• Level Ia lymph nodes
• Fatty tissue
• Small veins that drain into
anterior jugular veins.

13. • Submandibular triangle
• Contents
• lymph nodes - level Ib
• submandibular salivary gland
• lingual nerve, hypoglossal nerve
• marginal mandibular branch of FN
• facial artery and veins

14. • Carotid triangle
• Contents
• Lymph nodes of jugular chain
• CCA and its branches
• IJV and its tributaries
• Vagus nerve
• Hypoglossal nerve
• Superior laryngeal nerve

15. • Muscular triangle:
• Contents
• Lower part of the carotid sheath
• Sternohyoid, sternothyroid,
thyrohyoid muscles
• Thyroid and parathyroid glands
• Upper aerodigestive tract

16. • Posterior triangle
• Divided by inferior belly of omohyoid
into
• Occipital triangle
• Supraclavicular triangles

17. • Posterior triangle
• Contents:
• Omohyoid muscle
• Arteries:
a) Subclavian (3rd part)
b) Transverse cervical & suprascapular
c) Occipital

18. • Nerves
a) cervical plexus
b) branchial plexus
c) spinal accessory nerve
• Lymphnode

19. MARGINAL MANDIBULAR NERVE
• Landmarks:
1 cm anterior and inferior to angle of
mandible
• Course
• Passes antero-medially across upper neck in
plane just deep to platysma muscle
• But superficial to investing layer

20. • Can extend as low as greater cornu of
hyoid
• Passing superficial to facial vessels and
across mandible to provide motor
supply to
a) depressor anguli oris,
b) depressor labii inferioris and
c) mentalis muscle

21. • Facial nerve is most at risk during
• Submandibular gland excision
• Clearance of lymph node level Ib
• Facial nerve can be protected by
• Incising investing layer to lower border of SMG or
just above hyoid bone
• Reflecting fascia superiorly along with facial vein
• Thus, retracting nerve out of surgical field

22. HYPOGLOSSAL NERVE
• After exiting skull via hypoglossal canal
• Nerve runs deep to IJV
• Then curves around carotid bifurcation as it heads
anteriorly
• Passing inferior to greater horn of hyoid
• Coursing superiorly, superficial to hyoglossus
to reach tongue

23. • Susceptible to injury
• Floor of submandibular triangle, just
deep to duct
• During surgical procedures particularly
at its lowest point near hyoid

24. SPINAL ACCESSORY NERVE
• Exit skull via jugular foramen
• Can be located over transverse process of atlas
• Descends obliquely in level II (forms Level IIa
and IIb)
• Enters SCM muscle
• Exits posterior border of SCM - 1 cm above
Erb’s point
• Course across posterior triangle - enter
trapezius

25. • Importance
• Important landmark in sub-dividing lymph node
levels IIa and IIb.
• All important structures in posterior triangle lies
caudal to SAN
• Surgical consideration
• Most commonly injured during level 5 neck
dissection

26. THORACIC DUCT
• Located to right and behind left CCA and vagus
nerve
• Arches upward, forward and laterally, passing
behind IJV
• In front of anterior scalene muscle and phrenic
nerve
• Opens into IJV, subclavian vein or angle formed
by their junction

27. CERVICAL LYMPHATICS
• Divided into superficial and deep lymphatics
• Superficial lymphatics
• Drain skin and perforate investing layer of deep
cervical fascia - drain into deep system
• Deep lymphatics
• Proximity to vessels, nerves and muscles of neck.
• Over 80% of lymph nodes - closely related to IJV

28. LYMPH NODE LEVELS
• Originates from memorial sloan kettering
hospital,
new york
• Was adopted by AAOHNS in 1991

29. • LEVEL I
• Ia
• Chin
• Lower lip
• Mandibular incisors
• Anterior floor of mouth
• Tip of tongue

30. • Ib
• Oral Cavity
Floor of mouth
Oral tongue
• Nasal cavity (anterior)
• Face

31. • LEVEL II
• First echelon lymph nodes of
oropharynx
• Oral cavity
• Nasopharynx
• Hypopharynx
• Parotid gland

32. • Level III
• Lower areas of Oropharynx
• Hypopharynx
• Larynx

33. • LEVEL IV
• Hypopharynx
• Larynx
• Thyroid
• Cervical esophagus

34. • LEVEL V
• From all other nodal areas
• Nasopharynx
• Posterior neck
• Cutaneous scalp primary lesions

35. • Level VI
• Thyroid
• Larynx (glottic and subglottic)
• Pyriform sinus apex
• Cervical esophagus

36. • Level VII
• Superior mediastinum node
• Harbour metastasis from
• Thyroid
• Larynx ( Subglottis )
• Trachea
• Cervical oesophagus

37. • STAGING : NODALCLASSIFICATION
• Nx: Regional lymph nodes cannot be assessed
• N0: No regional lymph node metastases
• N1: Single ipsilateral lymph node, < 3 cm

38. • N2a: Single ipsilateral lymph node more
than 3
to 6 cm
• N2b: Multiple ipsilateral lymph nodes < 6
cm
• N2c: Bilateral or contralateral nodes < 6cm
• N3a: Metastases > 6 cm
• N3b: Metastasis in single or multiple LN
with

39. • THYROID
• N1a – Metastasis in level VI ( pretracheal, paratracheal, prelaryngeal) or
superior mediastinum
• N1b – Metastasis in other unilateral, bilateral or contralateral cervical (
level I, II,
III, IV, V) or Retropharyngeal

40. • NASOPHARYNX
• NI - unilateral < 6 cm, above caudal border of cricoid cartilage
• N2 - bilateral < 6 cm, above caudal border of cricoid cartilage
• N3 - > 6 cm and/or extension below caudal border of cricoid cartilage

41. NECK DISSECTION
• Systemic removal of lymph nodes with their
fibrofatty tissues from various compartments of neck
• Neck dissection classification
• In 1991, published the classification
(AAO-HNS)
• Later modified in 2001

42. • Academy’s classification (1991)
• Radical neck dissection (RND)
• Modified radical neck dissection (MRND)
• Selective neck dissection (SND)
• Supra-omohyoid type
• Lateral type
• Posterolateral type
• Anterior compartment type
• Extended radical neck dissection

43. • Academy’s classification (2001)
• Radical neck dissection
• Modified radical neck dissection
• Selective neck dissection
• SND ( I to III/IV )
• SND ( II to IV )
• SND ( II to V, Postauricular, Suboccipital )
• SND ( level VI )
• Extended neck dissection

44. • Medina classification (1989)
• Comprehensive neck dissection
• Radical neck dissection
• Modified radical neck dissection
– Type I (XI preserved)
– Type II (XI, IJV preserved)
– Type III (XI, IJV, and SCM preserved)
• Selective neck dissection

45. RADICAL NECK DISSECTION
• Removes
• Lymph nodes in level I-V + fibrofatty tissue
• Non lymphatic structures :
• SAN, IJV, SCM

46. • Indications
• Significant operable neck disease with tumor bulk
near to or directly involving SAN and/or IJV
• Reccurent disease after previous surgery or RT
• Clinical signs of gross extranodal disease

47. • Contraindications
• Untreatable primary tumor
• Unresectable neck disease
• Unfit for major surgery
• Distant metastases

48. • Preoperative preparation
• Patient counselling
risks and possible complications
• Prophylactic antibiotic
for 24 hours
aerobic, anaerobic and Gram-negative bacteria
• Elective tracheostomy
patient undergoing bilateral neck dissection

49. • Position
• Supine on operating table
• Head turned to opposite side
• Sandbag under shoulders
• Upper end table elevation to 30 degree
• Draping

50. • Incision for neck dissection
Hockey stick Boomerang Bilateral Boomerang

51. McFee Apron or Bilateral
hockey
Modified apron

52. Schobinger Modified schobinger Utilit
y

54. • Four areas of special attention
• Lower end of IJV
• Junction of lateral border of clavicle with lower
edge of trapezius
• Upper end of IJV
• Submandibular triangle

55. • Incision
• Through skin down to platysma
• Raise flap in subplatysmal plane
• Preserve marginal mandibular and
if possible cervical branch of facial nerve.

56. • First area of special attention
• Lower end of IJV
• Dissection along upper border of clavicle
from trapezius to suprasternal notch.
• Divide supraclavicular nerves and vessels
• Divide SCM above clavicle
Dissection of lower end of
SCM

57. • IJV visualized
between sternal and clavicular heads of
SCM
• Open carotid sheath
• Expose few centimetres of IJV
• Place 3 ligating sutures (vicryl 0/0)
around vein
• Retract carotid artery and vagus nerve
medially
Ligation of internal jugular
vein.

58. • Extend dissection laterally towards
Chaissaignac’s triangle
• Remove scalene nodes

59. • Second area of special attention:
• Junction of clavicle and anterior border
trapezius
• Begin dissection at lower end of
trapezius
• Divide fatty tissues in supraclavicular
region
• Cut inferior belly of omohyoid
• Ligate transverse cervical vessels

60. • Continue dissection on to underlying level of
prevertebral fascia
• Identify and preserve brachial plexus and phrenic
nerve
• Continue dissection to anterior border of
trapezius
• Proceed upward direction, dissecting posterior
triangle

61. • Dissection of posterior triangle
• Continue dissection to uppermost point
of triangle at mastoid tip
• Clear posterior triangle
• Dissect
• Proximal attachment of SCM
• lower lobe of parotid

62. • Third area of special attention
• Upper end of internal jugular vein
• Clear posterior belly of digastric
• Retract superiorly to expose IJV and
accessory nerve
• Clear vein and mobilize over a few cm
• Divide IJV after ligation and transfixion
Retraction of posterior belly of
digastric muscle to show upper
end of internal jugular vein

63. • Mobilize specimen from
cranial and caudal direction
• Follow anterior belly of omohyoid to
insertion at hyoid bone and divide

64. • Fourth area of special attention:
• Submandibular triangle
• Divide fatty tissue on dissection
plane
• Dissect fascia including SMG
• Ligate facial artery and vein
• Retract mylohyoid muscle medially
and
SMG inferolaterally
Anatomy of submandibular triangle.

65. • Floor visible and Identify lingual and
hypoglossal nerve
• Divide submandibular duct
• Ligate facial artery – posterior inferior
border of SMG

66. • Remove entire specimen
• Complete haemostasis
• Wound irrigation with saline
• Neck drains
• Closure of incisions
• two layers

67. MODIFIED RADICAL NECK DISSECTION
• En bloc removal of lymph node–
bearing tissue from one side of neck
(levels I to V).
• Preserves
• SAN, IJV, SCM (any combination)

68. • Three types (Medina 1989)
• Type I: Preservation of SAN
• Type II: Preservation of SAN and IJV
• Type III: Preservation of SAN, IJV, and
SCM

69. • MRND Type I
• Indications
• Clinically obvious lymph node
metastases
• SAN not involved by tumor

70. • MRND Type II
• Indications
• Rarely planned
• Intraoperative tumor found
adherent to SCM, but not IJV and
SAN

71. • MRND TYPE III
• Widely accepted
• N0 neck in patients with sq. cell ca. of
hypopharynx/larynx
• Differentiated Ca. thyroid with
palpable LN metastasis in posterior triangle

72. SPARING OF SAN
• Careful elevation of flap in posterior triangle
• Identification of SAN
a) located 1 cm above Erb’s Point
b) Entry point in ant border of trapezius 5 cm above
clavicle
c) Cranial part of SAN:
Runs along with IJV and crosses it medially to
laterally and
Transverse process of atlas

73. SELECTIVE NECK DISSECTIONS
• Definition
• Procedure where one or more LN groups are preserved in addition to
non- lymphatic structures
• Four common subtypes:
• Supraomohyoid neck dissection
• Lateral neck dissection
• Posterolateral neck dissection
• Anterior neck dissection

74. • Selective Neck Dissection( 1-III )
• Supraomohyoid neck dissection
• En bloc removal of cervical lymph node groups I to III
• Indications
• Oral cavity carcinoma (T1 –T4 with N0 neck)
• N1 in upper neck if
postoperative radiation therapy planned

75. • Bilateral SOHND
• Anterior tongue Ca.
• FOM Ca. that approach the midline

76. • Selective Neck Dissection (I-IV)
• Extended supraomohyoid neck dissection
• Cancer of anterolateral part of tongue

77. • Selective Neck Dissection: Level II-IV
• Lateral neck dissection
• En bloc removal of jugular lymph nodes
(Levels II-IV)

78. • Indications
• N0 neck in carcinomas of
Oropharynx
Hypopharynx
Larynx
• Laryngeal Ca. with subglottic extension, Hypopharyngeal Ca, MTC
SND (II to IV and VI).
• If risk for bilateral metastasis : Bilateral SND (II to IV)

79. • SND: Level II-V+ suboccipital and postauricular LN
• Posterolateral neck dissection
• Indications
• Cutaneous malignancies
• Melanoma
• Squamous cell carcinoma
• Merkel cell carcinoma
• Soft tissue sarcomas of scalp and neck

80. • Selective Neck Dissection : Level VI
• Central compartment dissection
• En bloc removal of level VI lymph
structures

81. • Indications
• Thyroid carcinoma
• laryngeal cancer (Advanced glottic and
subglottic)
• Advanced pyriform sinus cancer
• Cervical esophagus cancer
• Tracheal cancer

82. EXTENDED NECK DISSECTION
• Definition
• Removal of one or more additional lymph node
groups and/or non-lymphatic structures relative
to RND
• Eg, level VII, Retropharygeal node,
Hypoglossal nerve,
Carotid artery, Skin of neck

83. SEQUELAE OF RADICAL NECK DISSECTION
• Removal of spinal accessory nerve
• Loss of trapezius function
• Decrease ability to abduct shoulder > 90
degrees
• Destabilization of scapula
• Shoulder syndrome of pain, weakness and
deformity of shoulder girdle

84. COMPLICATIONS OF NECK DISSECTION
• 4 types
• Intra operative
• Early post operative
• Intermediate operative
• Late complications

85. INTRAOPERATIVE COMPLICATIONS
• Injury to local blood vessels and nerves
• SAN
• Cervical plexus, Brachial plexus
• Marginal mandibular nerve
• Vagus nerve, Hypogloasal nerve, Phrenic nerve
• Thoracic duct injury

86. EARLY POST OPERATIVE COMPLICATIONS
• Haemorrhage:
• May need re-exploration.
• Airway obstruction
• Temporary elective tracheotomy to protect airway.
• Increased intracranial pressure
• If persists, head end elevation, steroids and mannitol

87. • Carotid sinus syndrome
May result in hypotension and bradycardia
• Pneumothorax
• Air leaks

88. INTERMEDIATE POST OPERATIVE COMPLICATIONS
• Carotid artery rupture
• Fatal complication resulting in immediate mortality
• Immediate finger pressure, airway management, blood transfusion
and exploration in OT
• Prevention : Use of free and pedicled flap for closure of defect
• Deep vein thrombosis
• Pulmonary complications:
• Basal collapse and bronchopneumonia

89. CHYLOUS LEAK
• Intraoperative
• Apparent as clear fluid - confirmed by increased
flow on valsalva manoeuvre
• Vessel - quite fragile and surrounded by fatty
tissue - prone to tearing

90. • Management
• Direct clamping and ligating
• If this fails,
Fibrin sealant or vicryl mesh may be used
• Muscle flaps can be used in severe cases
• Diathermy does not seal fragile lymphatic vessels

91. • Postoperative
• Presence of milky appearance in neck drain after starting feed
• Confirmed either by
• Identifying triglycerides >100mg/dl or
• Reduction in volume of drain fluid on stopping enteral feed

92. • Management
• Low output leak - close spontaneously or
Managed with aspiration, pressure dressing and low fat elemental diet
• Surgical re-exploration and ligation of the duct is advised in
a) presence of complications (e.g. flap necrosis),
b) ‘high output leak’ (300mL/ day )
• If neck exploration fails - Thoracoscopic ligation of thoracic duct

93. LATE POSTOPERATIVE COMPLICATIONS
• Lymph edema
If both IJV ligated , block of lymphatic drainage from head.
• Hypertrophic scars