Download MBBS Surgery Presentations 53 Submandibular Lecture Notes

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