Download MBBS (Bachelor of Medicine, Bachelor of Surgery) 1st Year, 2nd Year, 3rd Year and Final year Surgery 53 Submandibular PPT-Powerpoint Presentations and lecture notes
Submandibular gland:
Surgical Anatomy
Tumors
Surgery
Dept Of Surgery
Surgical Anatomy
? Composed of a superficial part and a deep part.
? Superficial part: lies in the submandibular triangle
between two bellies of digastric muscle
? Deep part: lies below and lateral to the line of the
submandibular duct, in the floor of the mouth, above and
deep to the mylohyoid.
? Borders
? Lateral ? proximal half of the mandible.
? Posterior ? anterior to but near the low anterior margin of the
parotid gland.
? Inferior ? approaches the level of the hyoid bone.
? Majority of gland lies over the external surface of the mylohyoid
muscle.
? Lateral to and abuts the lingual and hypoglossal nerve and is
medial to the marginal mandibular and cervical branch of the
facial nerve.
? Drains through Wharton's duct in anterior floor of the
mouth
? Lymphatic Drainage Level IB
Submandibular ganglion is attached to the nerve at this point and
is also within the sheath of the gland
Submandibular duct lies beneath the lingual nerve as it emerges
from the upper pole of the gland.
Lingual nerve lies first between the duct and the deep part of the
gland, then crosses medially beneath the duct to ascend on the
hyoglossus to supply the tongue.
In some subjects a posterior sublingual gland drains into the
submandibular duct
Bartholin's major sublingual gland may drain via A single duct into
the submandibular duct or by a separate open
Salivary Gland Tumors
Epidemiology
? Relatively uncommon ? 2% of head and neck neoplasms
? Diverse histopathology
Distribution
? Parotid: 80% overall; 80% benign; 25% malignant
?
? Submandibular: 15% overall; 50% benign;43%malignant
? Sublingual/Minor: 5% overall; 40% benign;65%malignant
? Preponderance of benign tumors in women
? Malignant tumors exhibit an equal sex distribution
? Patients with benign tumors are younger (mean age: 46
years) compared with those with malignant tumors (mean
age: 54 years)
? Trend to an older age for submandibular and minor salivary
gland locations
Risk factors
? Nutrition: low intake of vitamins
? Smoking
? Irradiation
? Ultraviolet exposure (controversial)
Molecular targeting
Recent interest in molecular targeting of salivary gland
malignancies
Molecular markers
? EGFR
Overexpression in all histologic subtypes
? HER2
Ductal carcinoma
? C-kit
Adenoid cystic
Although there is overexpression of these molecular markers, the
rates of true genetic mutation is much lower
Clinical Presentation
? Painless, rapidly enlarging mass
? Indolent period >10 years
? Pain is more frequently associated with malignant
disease
Clinical features suggesting a malignant tumour:
? Rapid growth rate
? Pain
? Facial nerve palsy
? Childhood occurrence
? Skin involvement
? Cervical adenopathy
WHO classification of salivary gland tumors
Morphology
? Pleomorphic adenomas:
originate from the intercalated duct cells and myoepithelial
cells
? Oncocytic tumors:
originate from the striated duct cells
? Acinic cell tumors:
originate from the acinar cells
? Mucoepidermoid & squamous cell carcinomas:
develop in the excretory duct cells.
Diagnostic Work-Up
? History /Physical Examination
? Computed tomography (CT) scans
? Magnetic resonance imaging (MRI)
(T1-weighted images are excellent to assess the margins, deep extent,
and patterns of infiltration because the (fatty) background of the gland is
hyperintensive)
Perineural invasion may be evaluated with both CT and MRI
? PET CT Scan
Potential role for staging and management in salivary gland carcinomas
? Fine-needle aspiration cytology
Axial CT scan showing left submandibular gland lesion
MRI scan showing right submandibular gland lesion
PET CT scan showing right submandibular gland lesion
Treatment
? Surgery
? Radiotherapy
? Chemotherapy (not efficacious)
Surgery
? Mainstay of treatment
? Submandibular Gland excision with level Ib dissection
recommended
? Radical resection is indicated with tumors that invade the
mandible, tongue, or floor of mouth
Submandibular Triangle Dissection
? Scalpel proceeds through the skin in a curvilinear incision from
just off the midline anteriorly to just below the earlobe posteriorly
? Flap is elevated deep to platysma muscle
? Surgeon must be aware of the course of the marginal branch of
the facial nerve.
? It is important to identify this nerve and mobilize it anteriorly and
posteriorly.
Incision site for submandibular triangle
dissection
Incision for combined neck dissection
Skin flap raised superiorly with platysma muscle left in place
Skin flap raised superiorly with platysma muscle
Marginal branch of the facial nerve and its
relationship with the facial vessels
Detail of the submandibular triangle with the submaxil ary gland resected
Management of Neck
Management of the N0 neck
? Tumors >4cm
? High grade histology
Management of the N+ neck
? Ipsilateral MRND for clinically or radiographically positive
nodes
? Incidence of multilevel node involvement
Postoperative Radiotherapy
Indications
? T3-4 tumors
? Close or positive margin
? Incomplete resection
? Bone involvement
? Perineural invasion
? Positive nodes
? Recurrent cancer
Prognosis
? Survival of patients with submandibular cancers is inferior
to that of parotid cancers
? Perineural invasion: independent prognostic factor for
distant metastases or DFS
? Impairment of function of the facial nerve : poor DFS
? Acinic cell and (low-grade)mucoepidermoid cancer: best
prognosis
? Undifferentiated & squamous cell cancer: worst prognosis
This post was last modified on 08 April 2022