submandibular gland excision
TRANSCRIPT
Excision of Submandibular Gland
Dr.Maamon Ameen
ANATOMY
• Submandibular gland is one of the three paired salivary glands. • Size of a walnut• Mixed gland with predominantly serous in
type • Responsible for about 70% of salivary
secretion.
ANATOMY• Situation: Digastric triangle and lodges partly
in the submandibular fossa of the mandible• Part of gland : Large superficial part Small
deep part continous with each other around the post. Border of mylohyoid
ANATOMY
ANATOMYWhartons duct• 5 cm long• Emerges at the anterior end of
deep part of the gland• Runs forwards on hyoglossus b/w
lingual and hypoglossal N• At the ant. Border of hyoglossus it
is crossed by lingual nerve• Opens in the floor of mouth at the
side of frenulum of tongue
SURGICAL ANATOMY
The digastric muscle • forms the anteroinferior and
posteroinferior boundaries of the submandibular triangle.
• It is an important surgical landmark as there are no important structures lateral to the muscle.
• The facial artery emerges from immediately medial to the posterior belly, and the XIIn runs immediately deep to the digastric tendon.
SURGICAL ANATOMY
Mylohyoid muscle • key structure when excising the
SMG, as it forms the floor of the mouth, and separates the cervical from the oral part of the SMG.• The lingual and XIIn are both
deep to the muscle.
SURGICAL ANATOMY
Marginal mandibular nerve • Is at risk of injury.• It runs within the investing layers of deep
cervical fascia overlying the gland.• May loop up to 3cms below the ramus of
the mandible. • It crosses over the facial artery and vein
before ascending to innervate the depressor anguli oris muscle of the lower lip.
SURGICAL ANATOMY 3 methods of preserving
1. Approaching the gland at the level of hyoid bone, and keeping the dissection deep to the glands facial covering.
2. Dividing the facial vessels well below the mandible and on lifting up the upper ligated stumps.
3. Identify tail of parotid where it lies anterior to retromandibular vein and to trace it forward
SURGICAL ANATOMY
lingual nerve • comes into view during SMG excision
when the SMG is retracted inferiorly, and the mylohyoid is retracted anteriorly.
SURGICAL ANATOMY Hypoglossal nerve (XIIn) • Enters the submandibular triangle
posteroinferiorly and medial to the hyoid bone.
• The XIIn is covered by a thin layer of fascia, distinct from the SMG capsule.• Accompanied by thin walled ranine veins that
are easily torn at surgery.
SURGICAL ANATOMY Facial artery • Enters the submandibular triangle
Posteroinferiorly from behind the posterior belly of digastric and stylohyoid.• Courses across the posteromedial
surface of the SMG.• Reappears at the superior aspect of the
SMG where it joins the facial vein to cross the mandible.
Excision of Submandibular Gland
Indications • Repeated enlargement of the gland. • Salivary gland calculi• Chronic salivary gland infection.• Duct stenosis • Suspected submandibular neoplasm
PREOPERATIVE EVALUATION History• History of swellings (onset ,duration, recurrence )• Pain• Variation with meals• Bilateral• Dry mouth• Radiation history• Recent operative history
Excision of Submandibular Gland
Examination : Inspection• Asymmetry (glands, face, neck)• Diffuse or focal enlargement• Erythema • Trismus• Medial displacement of structures intraorally• Cranial nerve examination
Excision of Submandibular Gland
Examination : Palpation• Bimanual palpation of floor of mouth in
a posterior to anterior direction.• Palpation of duct papilla.• Bimanual palpation of the gland (firm
or spongy)• Palpate for cervical lymhadenopathy
Excision of Submandibular Gland
INVESTIGTIONS • Plain X-ray• Ultrasound• Sialography • CT and MRI scanning• Fine-Needle Aspiration Biopsy
Excision of Submandibular Gland
LATERAL MANDIBULAR VIEW TRANSORAL OCCLUSAL VIEW
Excision of Submandibular Gland
Advantagedetects
radiolucent stones
Disadvantage
• invasive• bleeding &
perforations
contraindicated• acute infections• allergic to
contrast
Sialography
Excision of Submandibular Gland
Ultrasound: differntiate between • solid versus cystic lesion • Intrinsic from extrinsic
Excision of Submandibular Gland
CT scaninvolvement of the mandible, the presence or absence of pathologic lymphadenopathy local extent of the tumor.
Excision of Submandibular Gland
Fine-Needle Aspiration Biopsy • Useful tool for differentiating chronic inflammatory disease
from neoplasia.
Excision of Submandibular Gland
Surgical approaches
• Transcervical approach• Transoral approach
Excision of Submandibular Gland
Trans-cervical approach
TRANS-CERVICAL APPROACH
Informed ConsentMarginal mandibular nerve>possibility of weakness of
the lower lip. Lingual > numbness of the tongue Hypoglossal nerves > paralysis of the tongue on the
operated side
OPERATION STEPSAnesthesia • General anesthesia • Avoid muscle relaxant to monitor lower lip movement
TRANS-CERVICAL APPROACH
OPERATION STEPS
• Positioning and draping
• Incision 3-4 cm below the mandible or at the level of hyoid bone
• The incision is carried through skin,
subcutaneous tissue and platysma to expose the capsule of the SMG, the facial vein and posteriorly, the external jugular vein
• The facial vein is ligated and divided where it crosses the SMG
• The fascial capsule of the SMG is incised• subcapsular dissection
• Dissect bluntly with a hemostat in the fatty tissue above the gland to identify the facial artery and vein • Divide and ligate facial artery
and vein as close as possible to SMG.
• Front-to-back mobilisation of SMG off mylohyoid muscle, and division of mylohyoid nerve and vessels to gain access to the posterior border of mylohyoid muscle
• Exposing posterior part of mylohyoid
• Retracting mylohyoid brings lingual nerve, XIIn and submandibular duct into view
• Finger dissection in plane between SMG and fascia covering XIIn and ranine veins
• Division and ligation of submandibular duct and submandibular ganglion• follow and divide the duct more
anteriorly if surgery for sialolithiasis so as not to leave behind a calculus
• The SMG can then be reflected inferiorly, and the facial artery is identified, ligated and divided where if exits from behind the posterior belly of digastric
• The SMG is then finally freed from the tendon and posterior belly of the digastric and removed
• Wound irrigation• Placement of suction drain• Wound is closed in layers
Post-operative management• Head end elevation• NPO for 4-6hours• Patient observed for airway compromise• Monitoring of vital signs• I/V antibiotics• Analgesics• Removal of drain after 24-48hrs
Excision of Submandibular Gland
Complications• General• Hematoma • Infection
• Specific• Marginal mandibular nerve injury• Lingual nerve injury• Hypoglossal nerve injury• Retained calculi in duct
Excision of Submandibular Gland
Trans-oral approach
• The submandibular gland can be safely and successfully removed through an intraoral approach in a select population of patients with benign pathology
TRANS-ORAL APPROACH
Advantages of the transoral approach• less risk of injury to the marginal mandibular nerve • Avoidance of an external scar • Minimal risk of postoperative mucocele formation, or
inflammation of Wharton’s duct
TRANS-ORAL APPROACH
Disadvantages • Narrow surgical field • Scar contracture in the floor of mouth • Temporary or permanent restriction of tongue movement, • Abnormal tongue sensation
Contraindication • Suspected or proven malignancy, • Extensive scarring from prior abscessed gland • Surgeon lack of familiarity with the procedure
TRANS-ORAL APPROACH
• Nasotracheal intubation• Injection of lidocaine with
epinephrine• Insertion of a probe into the orifice
of Wharton's duct
TRANS-ORAL APPROACH
• An incision is made in the floor of mouth from the submandibular papilla to the retromolar trigone.• A cuff of mucosa on the gingival side
is preserved to allow for tension free closure and to prevent limitation of tongue mobility due to scar contracture
TRANS-ORAL APPROACH
• The lingual nerve is identified and dissected free of its attachments to the submandibular duct and gland
TRANS-ORAL APPROACH
• The submandibular gland is bluntly dissected and delivered into the surgical wound by applying external pressure on the neck• Branches of the facial artery and
vein are ligated with care not to disrupt the marginal mandibular branch of the facial nerve.
TRANS-ORAL APPROACH
• The hypoglossal nerve is identified and preserved.
TRANS-ORAL APPROACH
• The gland is removed• Wound bed irrigated and closed in a tension free manor
TRANS-ORAL APPROACH
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