PAROTID ANATOMY & SURGER

Views:
 
Category: Entertainment
     
 

Presentation Description

No description available.

Comments

Presentation Transcript

PAROTID GLANDS:

PAROTID GLANDS Paired parotid glands are largest of salivary glands

Parotid Gland:

Parotid Gland below and in front of the external auditory meatus behind the ramus of the mandible Wedge-shaped when viewed externally , with the base above & the apex behind the angle of the mandible

PowerPoint Presentation:

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

Lobes:

Lobes The facial nerve courses horizontally through the gland and divides it into: Superficial lobe Deep lobe Superficial lobe Deep lobe Facial nerve

GROSS ANATOMY:

GROSS ANATOMY Weight – 25g. Shape – Inverted pyramid. Surface – Irregular, lobulated.

PowerPoint Presentation:

Site – in the parotid region bounded by Front – posterior border of body of ramus. Behind – mastoid process and sternocleidomastoid muscle. Below – digastric and stylohyoid. Above – external acoustic meatus and TMJ. Medially – Styloid process.

Capsules:

Capsules two capsules: An inner connective tissue capsule An outer dense fibrous capsule derived from the investing layer of the deep cervical fascia 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

RELATIONS:

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

PowerPoint Presentation:

Anteromedial : Stylomandibular ligament Medial pterygoid Posterior border of the ramus of mandible Massater Terminal branches of the facial nerve Temporo-mandibular joint

PowerPoint Presentation:

Posteromedial : Carotid sheath with its contents Styloid process & attached muscles Facial nerve Posterior belly of digastric muscle Mastoid process Sternocleidomastoid

The Parotid Bed:

The Parotid Bed

Structures Within Parotid Gland:

Structures Within 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

PowerPoint Presentation:

Apex – overlaps posterior belly of digastric and part of carotid triangle . Structures through the apex cervical branch of facial nerve. anterior division of retro-mandibular vein. Formation of external jugular vein.

PowerPoint Presentation:

Base – related to external acoustic meatus and posterior aspect of TM joint. Structures through the base – Temporal branch of facial nerve. Superficial temporal vessels. Auriculotemporal nerve.

Processes:

Processes Glenoid process , that extends upward behind the TMJ, in front of external auditory meatus Facial process , that extends anteriorly onto the masseter muscle Accessory process 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 The gland is an irregular lobulated mass, sends ‘ processes ’ in various directions.

Parotid (Stensen’s) Duct:

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

PowerPoint Presentation:

Turns around the anterior border of masseter muscle Pierces the: Buccal pad of fat Buccopharyngeal fascia Buccinator muscle & Buccal mucosa Parotid duct Buccinator Masseter

PowerPoint Presentation:

Opens into the vestibule of mouth on a small papilla, opposite the second upper molar tooth

PowerPoint Presentation:

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

PowerPoint Presentation:

Lymph Drainage : Into the parotid & then into the deep cervical lymph nodes Parotid n. Deep cervical n.

Nerve Supply:

Nerve Supply Sensory : Auriculotemporal Autonomic : Sympathetic through plexus around the arteries (T1 → SCG → plexus around ECA) Parasympthetic through otic ganglion

Parasympathetic nerve supply.:

Parasympathetic nerve supply. Inferior salivatory nucleus. Tympanic branch of 9 th cranial nerve. Tympanic plexus Lesser petrosal nerve. Otic ganglion. Auriculotemporal nerve Parotid gland

Applied aspect.:

Applied aspect. Infections – Very painful due to unyielding nature of capsule. Retrograde bacterial infection may occur from mouth via duct.

PowerPoint Presentation:

Parotid abscess – drained by a small horizontal incision to avoid injury to branch of facial nerve .

Mumps:

Mumps infection via bloodstream caused by myxovirus parotiditis which has predilection for glandular and nervous tissues. Clinical features:- Fever Swelling of parotid Pain, tender

Complications:

Complications Complications of mumps: - Orchitis Oophoritis Pancreatitis Meningoencephalitis

PowerPoint Presentation:

Frey’s syndrome : a disorder characterized by recurrent episodes of localized facial flushing and/or sweating in the area over the parotid gland in response to gustatory stimuli This is due to aberrant nerve regeneration after injury (a communication develops between the auriculo -temporal & greater auricular nerves such that parasympathetic fibers migrate into the cutaneous sympathetic nerves that supply the sweat glands)

TUMOURS OF PAROTID:

TUMOURS OF PAROTID

Classification of Parotid Tumours:

Classification of Parotid Tumours Adenoma Pleomorphic Monomorphic ( Warthin’s Tumour ) Carcinoma Low grade ( Acinic cell/Adenoid cystic) High grade (Adenocarcinoma/SCC)

Parotid Tumours:

Parotid Tumours Most Common is pleomorphic adenoma (80-90%) Low grade Tumors like acinic cell carcinoma are not distinguishable from benign High grade Tumours grow rapidly, are often painful and have nodal metastasis CT/MRI are useful Tx should be excised & not enucleated

Management:

Management Superficial parotidectomy most common procedure Radical parotidectomy is performed for patients clear histological evidence of high grade malignancy

PowerPoint Presentation:

Parotid neoplasm's – Benign: - 1. Pleomorphic adenoma – most common. usually unilateral. slow growth symptomless apart from lump greyish white in color with possible cyst formation and hemorrhage.

PowerPoint Presentation:

It contains epithelial and mesodermal elements. Most common site in parotid – the tail of the gland, frequently elevating the earlobe . Cut section – Rubbery or soft or firm; whitish grey to pale yellow in colour . Commonly microscopic extensions extend through the capsule – ‘Pseudopods’ ‘Shelling’ of the tumours , leaving capsule intact leaves persistent microfoci ; leads to recurrence .

Pleomorphic adenoma:

Pleomorphic adenoma Readily implanted – spillage of tumour while excising – proliferation of the deposits – recurrence. Facial nerve at greater risk of injury during management of recurrent tumours Though relatively radio resistant, RT is indicated for repeated recurrences

Warthin’s tumour:

Warthin’s tumour Also known as Adenolymphoma or Papillary cystadenoma lymnphomatosum Almost exclusive to parotid Occurs in salivary tissue that’s incorporated embryologically in intraparotid nodes. 10-15% of all parotid tumours Male female ratio 7:1; peak age – 7 th decade 10% bilateral; may present at different times

Warthin’s tumour:

Warthin’s tumour Commonly occurs in the lower pole of the gland – ear lobe elevation is rare. Inflammation may occur due to lymphoid-rich stroma – pain, warmth and tenderness. Nodal architecture may be seen on microscopy Hot spots seen in radionuclide(Technetium) scan

Other benign tumours:

Other benign tumours Monomorphic adenoma Only the cellular components are seen without the chondromyxoid stroma Warthin’s tumour is an example. Basal cell adenomas – may be confused for enlarged nodes, seb . cysts, mucoceles , lipomas , etc. Oncocytoma Though histologially benign, they are locally invasive HPE: parking slot inclusions of mitochondria. Another tumour which takes up Technetium. Hemangioma : Most common benign tumour in children Usually seen in infant girls Usually undergo complete involution

Malignant :

Malignant 1. Adenoid cystic Carcinoma. 2. Adenocarcinoma. 3. Squamous cell carcinoma. 4. Malignant pleomorphic adenoma.

Mucoepidermoid ca:

Mucoepidermoid ca Most common malignant tumour . 80-90% of the tumours occur in the parotids ; Males and females affected with equal frequency ; peak age range 4 th decade. Two cellular components – mucin -producing cells, epithelial epidermoid cells . More the proportion of mucin -producing cells , lower the grade and better the prognosis .

Adenoid cystic ca:

Adenoid cystic ca Second-most common malignancy 2 % of parotid tumours Max . incidence – 6 th decade. Commonest clinical feature – facial pain Perineural spread is characteristic – accounts for large number of pre-op facial paralysis.Important route for skull-base and intracranial spread. Hematogenous mets cause pulmonary mets . Local spread leads to mandibular involvement .

Malignant mixed parotid tumour:

Malignant mixed parotid tumour May develop either from pre-existing benign tumour or may occur de novo. Malignant components of pre-existing tumours are purely epithelial – ‘Carcinoma ex-pleomorphic adenoma’ De novo tumours have malignant components in the myxoid stroma also – behave like sarcomas . Risk factor – prolonged existence of a benign pl. adenoma for 10-15 yrs. Excellent prognosis if tumour is excised completely .

Malignant tumours:

Malignant tumours Other tumours Salivary duct ca Behaves like infiltrating ductal ca breast. Very aggressive; 5-yr survival 0%. Lymphomas – Arise either from intraglandular nodes or from the lymphoid tissue dispersed in the gland stroma . Increased risk after Sjogren’s syndrome.

Signs of Malignancy:

Signs of Malignancy - Pain - Altered consistency - Rapidity of growth - Onset of Facial palsy - Tethering of skin - Involvement of bone - Development of nodes P A R O T I D

Clinical features:

Clinical features Some important aspects of examination which might be missed… Oral cavity examination to look for deep lobe involvement of the parotids. Clinical and radiological examination of the mandible Thorough examination of the facial nerve Thorough examination of the pharynx, esp. nasopharynx and the hypopharynx – Indirect laryngoscopy Examination of the temporo-mandibular joint

Clinical features:

Clinical features Features suggesting malignancy Sudden rapid growth Nerve involvement – Facial pain, Paralysis Skull base involvement – neurological symptoms Nodal metastasis – palpable neck nodes

PowerPoint Presentation:

AJCC(American Joint Convention on Cancer) staging based on T, N and M T staging: T 0 - No evidence of primary T 1 - Less than 2 cm in greatest dimension T 2 - 2 - 4 cm in greatest dimension T 3 - 4 – 6 cm in greatest dimension T 4 - More than 6 cm in greatest dimension a - without significant local extension b – significant local extension Local extension: Clinical or microscopic invasion of skin, soft tissue, bone, lingual or facial nerves

Staging:

Staging N staging: Nx - Nodal involvement can’t be assessed N 0 - No nodal mets N 1 - Single ipsilateral node, less than 3 cm N 2 - Multiple ipsilateral , contralateral or bilateral nodes None more than 6 cm N 3 - Nodes larger than 6 cm. M staging: M 0 - No distant metastasis M 1 - Distant metastasis present.

Staging:

Staging Stage 1 – T1a, T2a (<4 cm) Stage 2 – T1b, T2b, T3a (<4 cm +skin OR 4 – 6 cm ) Stage 3 – T3b, T4a; any T except T4b, with N1. (4 – 6 cm +skin OR > 6 cm OR any with LN < 3 cm I/L ) Stage 4 – T4b; any T with N 2 or 3; any T, any N with M1. (>6 cm +skin or any with LN > 3cm OR multiple OR mets )

Investigations:

Investigations FNAC: Common, well-established investigation; easy procedure Patient compliance good Intra-oral FNAC for deep lobe tumours controversial – may lead to tumour seeding along the needle tract; difficult to treat. CT scan: Contrast CT preferable. Good account of anatomical details of involved part Extension of tumor beyond the gland can be made out Bony destruction and skull base inv. can be made out Spiral CT - 3D reconstruction helps define tumors in three dimensions better .

Investigations:

Investigations MRI Superior to CT in evaluating intracranial spread. No risk of exposure to radiation Expensive Other investigations: Radionuclide scan – Technetium 99 scans produce hot spots due to uptake by tumour – esp. Warthin’s tumour Ultrasound – Differentiation b/w solid and cystic lesions Duplex scan – Evaluation of vascular anatomy of salivary glands Histopathology – Important in grading of tumours based on tumour architecture , cell atypia , nuclear characters . Grading is important in prognostication and staging of tumours .

Treatment:

Treatment Surgery Radiotherapy Chemotherapy-minimal use

Treatment - Surgery:

Treatment - Surgery Parotid gland: Benign tumours : Superficial lobe – Superficial conservative parotidectomy Deep lobe involvement – Total conservative parotidectomy Malignant tumours – Total conservative parotidectomy / Radical parotidectomy if facial nerve is involved Nodal involvement – Radical or Modified radical neck dissection.

Facial Nerve trunk-identification:

Facial Nerve trunk-identification TRAGAL POINTER Stylo mastoid foramen Post belly of Digastric muscle Tympanomastoid suture Patey’s plane

PowerPoint Presentation:

Mumford Incision

PowerPoint Presentation:

Adson & Ott ( Y incision )

PowerPoint Presentation:

Sistrunk Incision

PowerPoint Presentation:

Blair & Bailey modification - The lazy S incision

PowerPoint Presentation:

Appiandi, Terris & co - Face lift incision

Complications of surgery:

Complications of surgery Facial nerve paresis/paralysis Temporary paresis quite common due to traction injury during dissection Normal function returns generally by 4-6 weeks . Paralysis more common in case of recurrent surgery Inevitable for malignancy Treatment – nerve grafts using Sural or Gr.auricular nerve.

Complications of surgery:

Complications of surgery Frey’s syndrome Post-op gustatory sweating Due to cross-innervations of Auriculotemporal nerve Test – Starch-iodine test Treatment Conservative – antiperspirants Surgery – Ablation of the ATN Prevention – Placement of fascial patches after parotidectomies , before flap closure Lucja Frey -1923

Complications of surgery:

Complications of surgery Salivary fistula may occur due to damage to the ducts. Very rare. Cosmetic disfigurement due to emptiness in the parotid fossa. Necrosis of the skin flap, which can be prevented by raising a flap at least 5-6 mm thick

Radiotherapy:

Radiotherapy Adjuvant to surgery Indications Stage 3 or 4 tumours Large or fixed tumours Unfavourable histology – high-grade tumours Perineural invasion Margins of resection positive for malignancy Neck node metastasis Recurrent tumours , even benign ones Minor salivary gland tumours of the paranasal sinuses.

DIFFERENTIAL DIAGNOSES:

DIFFERENTIAL DIAGNOSES

Pilomatrixoma of the Parotid Region:

Pilomatrixoma of the Parotid Region Pilomatrixoma , or calcifying epithelioma of Malherbe , is an uncommon, benign, epithelial tumor of the skin that often arises in head and neck regions, in the first 2 decades of life. the presenting symptom was a hard, slow-growing, subcutaneous tumor Spontaneous regression is never observed. Complete surgical excision is the treatment of choice

Acinic Cell Carcinoma of the Parotid Gland:

Acinic Cell Carcinoma of the Parotid Gland Acinic cell carcinoma is a salivary tumour consisting of cells similar to the serous cells of salivary glands. Histologically , this rare neoplasm has a lattice-like appearance secondary to fluid collection, but a variety of forms have been described. Calcification may also be a prominent feature. Clinically, these malignancies may simulate pleomorphic adenomas, presenting as a single nodular mass over a long period of time. The vast majority present between the 3rd and 6th decade of life and are found in the parotid gland. The prevalence is higher amongst females by 2:1. These lesions may be painful, usually upon palpation, however; facial nerve palsies are rare

Squamous Cell Carcinoma:

Squamous Cell Carcinoma Primary squamous cell carcinoma of the parotid is uncommon, occurring in only 2% of parotid neoplasms . This is an aggressive malignancy, usually presenting in an advanced stage and associated with facial nerve involvement or cervical metastases. Prognosis is poor even with radical surgery and adjunctive radiotherapy. Careful clinical and histological review is necessary to differentiate primary squamous cancer of the parotid from metastases or other primary parotid malignancy.

Benign Cyst of the Parotid Gland:

Benign Cyst of the Parotid Gland painless, slowly-growing ,  cystic mass in the tail of her left parotid. normal parotid tissue is visible between the retracted  ear lobe  and the bluish cyst. Also, visible is the ground electrode of the facial nerve stimulator which is helful in localizing the facial nerve branches. Histologic examination revealed a benign cyst.

Hematoma of the Parotid Gland:

Hematoma of the Parotid Gland rapid swelling of the left parotid gland and ecchymosis of the surrounding skin .  The ecchymotic spot behind the ear mimicked Battle's sign , There were also some ecchymotic spots around the pore of Stensen's duct in the left cheek mucosa.

THANK YOU:

THANK YOU

authorStream Live Help