3. Parotid Gland
Largest of the salivary glands
Wedge-shaped when viewed externally, with the
base above & the apex behind the angle of the
mandible
4. Parotid Gland
Situated anteriorly and inferiorly to the
ear
Overlie the vertical mandibular rami
and masseter muscles, behind which
they extend into the retromandibular
sulci
Superiorly - zygomatic arches
Inferiorly - below the angles of the
mandible , overlie the posterior bellies
of the digastric & the sterno-
cleidomastoid muscles
5. Wedge-shaped in horizontal section with the base in the lateral position and apex against the
pharyngeal wall
It exhibits 3 surfaces:
Lateral
Anteromedial
Posteromedial
6. Superficial Muscular Aponeurotic System and Parotid
Fascia
Fibrous network that invests the facial muscles & connects them with the dermis
Continuous with the platysma inferiorly; superiorly it attaches to the zygomatic arch
Facial nerve courses deep to the SMAS and the platysma
Parotid glands are contained within two layers of parotid fascia, which extend from the zygoma
above and continue as cervical fascia below
7. Lobes
The facial nerve courses
horizontally through the gland and
divides it into:
Superficial lobe
Deep lobe
Superficial lobe
Deep lobe
Facial nerve
8. Processes
Glenoid process, that extends upward
behind the temporo-mandibular joint,
in front of external auditory meatus
Facial process, that extends anteriorly
onto the masseter muscle
Accessory process (part), small part of
facial process lying along the parotid
duct
Pterygoid process, that extends
forward from the deeper part, lies
between the medial pterygoid muscle
& the ramus of mandible
Carotid process, that lies posterior to
the external carotid artery
9. Capsules
The parotid gland is enclosed in two capsules:
An inner connective tissue capsule
An outer dense fibrous capsule derived from the investing
layer of the deep cervical fascia
The deep cervical fascia extends upward, reaches the inferior
border of parotid gland, splits into the superficial & the deep
layer, to enclose the gland
Above the gland, the:
Superficial layer gets attached to the zygomatic arch
Deep layer gets attached to the tympanic plate of
temporal bone
A portion of fascia extending from the styloid process to
the angle of mandible is called stylomandibular ligament.
It separates the parotid gland from the submandibular
gland
10. Relations
Superficial (lateral):
• Skin & superficial fascia
• Great auricular nerve
• Parotid lymph nodes
Superior:
• External auditory meatus
• Temporomandibular joint
• Its glenoid process is related to the
auriculo-temporal nerve
11. Anteromedial:
• Stylomandibular ligament
• Medial pterygoid
• Posterior border of the ramus of
mandible
• Massater
• Terminal branches of the facial
nerve
• Temporo-mandibular joint
12. Posteromedial:
• Carotid sheath with its contents
• Styloid process & attached muscles
• Facial nerve
• Posterior belly of digastric muscle
• Mastoid process
• Sternocleidomastoid
13. The Parotid Bed
The structures intimately related to the deep surface of the
parotid gland (anteromedial & posteromedial relations)
14. Structures Coursing Within the Parotid Gland
Auriculotemporal nerve
External carotid artery
Retromandibular vein
Facial nerve
A few lymph nodes are scattered in the
substance of the gland
Deep
Superficial
15. Parotid (Stensen’s) Duct
About 2 inches long
Emerges from the facial process of the
gland
Passes forward over the lateral surface
of the masseter muscle
about a fingerbreadth below the
zygomatic arch
accompanied by the:
transverse facial vessels & upper
zygomatic branches of facial nerve
above
lower zygomatic branches of facial
nerve below
16. Turns around the anterior border
of masseter muscle
Pierces the:
• Buccal pad of fat
• Buccopharyngeal fascia
• Buccinator muscle &
• Buccal mucosa
Opens into the vestibule of mouth
on a small papilla, opposite the
second upper molar tooth
Parotid duct
Buccinator
Masseter
Parotid (Stensen’s) Duct - course
17. The oblique passage of the duct in the buccinator muscle acts
as a valve-like mechanism & prevents inflation of the duct
during blowing
Parotid Duct
• The duct can be rolled over the
clenched masseter muscle
• The duct is represented by the
middle 1/3 of a line extending
from the tragus of the auricle to a
point midway between the ala of
nose & upper lip
18. Venous drainage
Maxillary and superficial temporal veins
merge into the retro-mandibular vein within
the parotid gland, but are not responsible for
draining the gland
Tributaries of external and internal jugular
veins
Retromandibular v.
20. Into the parotid & then into the
deep cervical lymph nodes
Parotid n.
Deep cervical n.
Lymphatic drainage
21. Nerve Supply
Sensory :
Auriculotemporal n.
Autonomic:
Sympathetic through plexus around the
arteries ( plexus around ECA)
Parasympthetic through otic ganglion
(CN9 → tympanic n. → tympanic plexus →
lesser petrosal n. → otic ganglion →
auriculotemporal n.)
22. Facial nerve
Exits the stylomastoid foramen enters the
parotid gland
Trunk divides at the pes anserinus
upper and lower division branch into
temporal (frontal), zygomatic, buccal, marginal
mandibular and cervical branches
Innervate the muscles of facial expression
Small branches to the posterior belly of
digastric, stylohyoid, and auricular muscles
23. Facial nerve – branches
A bout 2/3 of the gland substance being -
superficial to the nerve
Midfacial nerve branches - multiple cross-
innervations injury no loss of facial
function
Temporal & marginal mandibular branches do
not have cross-innervations injury to these
branches is followed by paralysis of the
forehead and depressors of the lower lip
24. Types of Parotidectomy
Partial parotidectomy:
Resection of parotid pathology with a margin of normal parotid tissue
Standard operation for benign pathology / favourable malignancies
Superficial parotidectomy:
Resection of the entire superficial lobe of parotid
Metastases to parotid lymph nodes / high grade malignant parotid tumours
Total parotidectomy:
Resection of the entire parotid gland, usually with preservation of the facial
25. Preoperative consent
Scar
Anaesthesia: greater auricular distribution: Skin of inferior part of auricle, and overlying the
angle of the mandible
Facial nerve weakness: Temporary weakness common (<50%); permanent weakness rare
Facial contour: loss of parotid tissue leads to a more defined angle of mandible/deepening of
retromandibular sulcus
Prominence of auricle: Due to loss of innervation of the postauricular muscles and preauricular
scarring
Frey’s syndrome (gustatory sweating)
26. Anaesthesia
General anaesthesia
Short-acting muscle relaxation for intubation only, so that facial nerve may be stimulated
and/or monitored
No perioperative antibiotics unless specifically indicated
Hyperextension of the neck, and turned to opposite side
Infiltrate with vasoconstrictor along planned skin incision, so as to reduce thermal injury to skin
from electro-cautery to skin vessels
Corners of the eye and mouth -- exposed to be able to see facial movement when facial
nerve mechanically or electrically stimulated
28. Parotidectomy
Superficial cervicofacial flap raised - anterior
border of parotid mass or of the parotid gland
in the plane between the SMAS and the
parotid fascia with a scalpel/diathermy
Assistant - monitor the face for muscle
contraction to avoid facial nerve injury
Traction suture placed in the subcutaneous
tissue of the ear lobule / anterior skin flap
secured to the drapes
29. Parotidectomy
Anterior border of sternocleidomastoid
skeltonized
External jugular vein – divided
Division of greater auricular nerve as it
crosses sternocleidomastoid muscle/posterior
to the external jugular vein
Digastric
SCM
EJV
Gr A
30. An attempt can be made to preserve the
posterior branch of the nerve to retain
sensation of the skin of the auricle
Posterior branch of greater auricular nerve
31. Identification and skeletonisation of posterior
belly of the digastric muscle
Cephalad dissection – avoided prevent
injury to the facial nerve
33. Facial nerve
Facial nerve trunk exits the skull at the
stylomastoid foramen
Situated at the deep end of the tympano-
mastoid suture line the junction between
the mastoid process and the tympanic ring of
the external ear canal
34. Temporal branch
Crosses the zygomatic arch
Runs within the SMAS and lies superficial to
the deep temporalis fascia
Courses along a line drawn between the
attachment of the lobule of the ear to a point
1.5 cm above the lateral aspect of the eyebrow
To avoid injury to the temporal branch
dissection done either in a subcutaneous
plane / deep to the SMAS
35. Intraoperative location of facial nerve
Prograde dissection
Nerve trunk dissection continued
anteriorly along the trunk, the pes anse-rinus
and the divisions and nerve branches
36. Intraoperative location of facial nerve
Retrograde dissection
Temporal branch where it crosses the zygoma
Buccal branches which lie parallel to the
parotid duct
37. Intraoperative location of facial nerve
Retrograde dissection
Marginal mandibular branch crosses the
facial artery and vein just below or at the
inferior margin of the mandible –> deep to
platysma
39. Facial nerve - surgical landmarks
Posterior belly of digastric muscle - same
depth, bisects the angle between the muscle
and the styloid process
Cartilage pointer: medial-most, pointed end
of the cartilage of the external auditory
meatus
Exits the foramen - 1cm deep and 1cm
inferior to this point
40. Facial nerve - surgical landmarks
Tympanomastoid suture line - most precise
landmark for the facial nerve leads medially,
directly to the stylomastoid foramen
Styloid process- Crosses the styloid process
palpating the styloid process useful to
determine the depth and position of the facial
nerve
Branch of occipital artery - branch of the
occipital artery is encountered lateral to the
facial nerve close to the stylomastoid foramen
Brisk arterial bleeding alert the surgeon to
the proximity of the facial nerve
41. Landmarks for the facial nerve
Tympanic ring
Facial nerve
Cartilage pointer
Digastric
Tympanomastoid
suture
Sternomastoid
Mastoid process
42. Dissection of facial nerve
Facial nerve trunk located by blunt dissection
with a fine haemostat
Fine curved blunt tipped scissors for the
remainder of the nerve dissection
It is important to dissect directly on the nerve
so as not to lose sight of it
Parotid tissue – should never be divided
beyond exposed facial nerve
43. Dissection of facial nerve
Dissection - along the trunk to the pes
anserinus
Facial nerve trunk dividing into superior and inferior divisions at
the pes anserinus
44. Dissection of facial nerve
Dissection - back towards the stylomastoid
foramen to exclude early branching from the
trunk
Division of the parotid fascia and parotid
tissue superiorly and inferiorly releases the
parotid posteriorly & permits anterior
mobilisation of the gland/tumour
Dissection along the nerve
Superficial lobe stripped off the branches of
facial nerve
46. Removal of the superior part of the gland,
identification/ligation the superficial temporal
artery superiorly anterior to auricle
Dissection at the anterior border of the gland
identification and transection the parotid
duct
Tumour removed with a cuff of the superficial
parotid lobe
47. Parotid dissection for deep lobe tumours
Identification, dissection of the facial nerve
off the underlying deep lobe or tumour to
provide access to the deep lobe
Superficial parotidectomy / reflecting the
superficial lobe anteriorly, with parotid duct
intact, and replaced at the conclusion of
surgery
48. Deep lobe
Tumour delivered either between, or inferior
to the facial nerve or its branches, after
identification of the branches of the facial
nerve around the tumour
Tumor removed between the splayed facial
nerve branches
49. Deep lobe
Deep lobe -delivered from the parapharyngeal
space by blunt dissection
Division of the external carotid, deep
transverse facial and superficial temporal
arteries and the retromandibular and
superficial temporal veins
Additional access – division of the styloid
process and/or via a transcervical approach
51. Tumour spillage
Great care should be taken to avoid rupture
and spillage of pleomorphic adenoma tissue
into the operative site
Multifocal tumour recurrence, often more
than 20yrs following surgery
Extensive ruptures - postoperative radiation
therapy
Multifocal recurrence of pleo-morphic adenoma
52. Wound closure
Confirm nerve continuity: Careful inspection/nerve stimulator
Obtain meticulous haemostasis: Using ties and bipolar diathermy/ Valsalva manoeuvre to
identify venous bleeding
Sealed suction drain: Until drainage <50ml/24 hrs
Skin closure: Subcutaneous and subcuticular absorbable sutures
53. Facial nerve repair
Transection of the temporal (frontal) and marginal mandibular nerves- repaired with 8/0
nylon/prolene epineural sutures
Undue tension / nerve resection- grafted with greater auricular nerve, or sural nerve
54. Greater auricular nerve
Approxi-mately the same diameter as the
facial nerve trunk
Few branches that can be used to graft more
than one facial nerve branch
55. Sural nerve
Greater length
more branches
better suited to bridging longer defects and for grafting to more peripheral branches
56. Hypoglossal-facial nerve interposition
Proximal end of the facial nerve is not
available, e.g. with extensive proximal
perineural tumour extension
Nerve graft sutured end-to-end to the
distal facial nerve and end-to-side to the
hypoglossal nerve
25% cutting made into the side of the
hypoglossal nerve to expose the nerve axons