Overview
Definition:
Submandibular gland excision, also known as submandibulectomy or sialadenectomy, is the surgical removal of the submandibular salivary gland
This procedure is indicated for a variety of benign and malignant conditions affecting the gland, including chronic sialadenitis, salivary stones causing recurrent obstruction, oncocytomas, Warthin tumors, and malignant neoplasms
The submandibular gland is one of the major salivary glands, located beneath the mandible in the submandibular triangle of the neck
Its removal requires careful dissection to preserve surrounding vital structures, most notably the marginal mandibular branch of the facial nerve, the lingual nerve, and the hypoglossal nerve.
Epidemiology:
Diseases of the submandibular gland are common, with inflammatory conditions and calculi being the most frequent
Benign tumors account for the majority of neoplastic lesions
While precise incidence data for submandibular gland excision is variable, it represents a significant proportion of salivary gland surgical procedures
Age and gender distribution depend on the underlying etiology
for instance, stone formation is more common in adults, while malignant tumors can occur across a broader age spectrum.
Clinical Significance:
Submandibular gland pathology can cause significant morbidity, including pain, swelling, infection, and functional impairment (e.g., difficulty with mastication and salivation)
Accurate diagnosis and appropriate surgical management are crucial to alleviate symptoms, prevent complications like abscess formation or facial nerve injury, and manage malignancies effectively
For surgical residents preparing for DNB and NEET SS examinations, understanding the anatomy, surgical approaches, potential pitfalls, and postoperative care of submandibular gland excision is essential for patient safety and successful outcomes.
Indications
Benign Conditions:
Recurrent or chronic sialadenitis unresponsive to conservative management
Symptomatic sialolithiasis (salivary stones) causing recurrent obstruction and inflammation
Benign tumors such as pleomorphic adenoma (adenoma ex pleomorphic), Warthin tumor (papillary cystadenoma lymphomatosum), and oncocytoma
Salivary gland cysts.
Malignant Conditions:
Primary malignant tumors of the submandibular gland, including mucoepidermoid carcinoma, adenoid cystic carcinoma, and adenocarcinoma
Metastatic disease to the submandibular lymph nodes requiring gland excision for oncologic control
Certain salivary gland sarcomas or lymphomas involving the gland.
Other Indications:
Sialadenosis causing significant cosmetic disfigurement or discomfort
Trauma to the gland requiring its removal
Historically, it was also a treatment for Sjögren's syndrome, but this is rarely performed now due to systemic treatment options.
Preoperative Preparation
History And Physical:
Detailed history of swelling, pain, fever, and duration of symptoms
Examination to assess gland size, consistency, tenderness, presence of palpable stones, and overlying skin changes
Careful assessment for lymphadenopathy and examination of cranial nerves, especially the facial nerve for any signs of weakness (important for marginal mandibular nerve integrity).
Imaging:
Ultrasound is the primary imaging modality for salivary glands, helping to assess gland size, detect stones, and characterize masses
CT scan or MRI may be indicated for larger tumors, suspected malignancy, or to better delineate anatomical relationships and involvement of surrounding structures
Sialography is less commonly used now but can outline ductal anatomy and obstruction.
Laboratory Investigations:
Complete blood count (CBC) to assess for infection or inflammation
Coagulation profile
Biopsy (fine needle aspiration cytology - FNAC) may be performed preoperatively to establish a diagnosis, especially for suspected masses, though definitive diagnosis is often post-excision
Culture and sensitivity if acute infection is suspected.
Anesthesia And Consent:
General anesthesia is typically preferred
Local anesthesia with sedation may be an option for very small benign lesions in cooperative patients
Informed consent must detail the risks of bleeding, infection, nerve injury (marginal mandibular nerve, lingual nerve, hypoglossal nerve), altered sensation, dry mouth, scar formation, and the need for potential further surgery if malignancy is found.
Surgical Management
Approach And Incision:
A curvilinear incision is typically made 2-3 cm below and parallel to the inferior border of the mandible, extending from the mastoid tip posteriorly to the midline anteriorly (Risdon incision or variations thereof)
Alternatively, a transverse incision mimicking a natural skin crease can be used for better cosmesis
The platysma muscle is divided, and dissection proceeds through subcutaneous tissue.
Dissection And Nerve Preservation:
The key step is identifying and protecting the marginal mandibular branch of the facial nerve, which lies superficial to the submandibular gland
Careful dissection along the inferior border of the mandible allows for retraction of the nerve superiorly or inferiorly as needed
The mylohyoid muscle is often divided to gain access to the deep lobe of the gland and the lingual nerve
The lingual nerve is a critical structure to identify and preserve, lying superior to the submandibular duct and deep to the hyoglossus muscle.
Gland Mobilization And Duct Ligation:
The gland is dissected from its surrounding tissues, including the mylohyoid and hyoglossus muscles
The submandibular duct, along with the lingual and hypoglossal nerves, are identified
The duct is ligated proximally as it enters the gland, and the gland is freed
Careful attention is paid to securing hemostasis throughout the dissection.
Closure And Drainage:
The wound is usually closed in layers
A drain (e.g., Penrose or Jackson-Pratt) is often placed to prevent seroma formation
The skin is closed with sutures or staples
The patient is advised to rest their voice and avoid excessive head and neck movements immediately postoperatively.
Postoperative Care
Monitoring:
Close monitoring for bleeding, hematoma formation, and signs of infection
Assessment of marginal mandibular nerve function (e.g., ability to smile symmetrically, not to droop the lower lip)
Assessment of lingual nerve function (taste and sensation to the anterior two-thirds of the tongue).
Pain Management:
Analgesics are provided as needed
Antibiotics may be prescribed prophylactically or if signs of infection develop.
Oral Hygiene And Nutrition:
Patients are encouraged to maintain good oral hygiene
A soft diet may be recommended initially
Adequate hydration is important, and patients may experience temporary xerostomia (dry mouth) due to disruption of parasympathetic innervation to the gland or damage to the lingual nerve.
Drain Management:
The drain is typically removed when the output is less than 30 ml per 24 hours, usually within 2-5 days postoperatively.
Complications
Early Complications:
Bleeding and hematoma formation: can be significant and may require re-exploration
Infection: superficial or deep wound infection, potentially leading to abscess
Marginal mandibular nerve injury: resulting in unilateral lower lip droop (paresis or paralysis), affecting smile and expression
Lingual nerve injury: leading to altered taste and sensation in the anterior two-thirds of the tongue
Salivary fistula: leakage of saliva from the wound, often due to incomplete ligation of the duct or trauma to adjacent ducts
Seroma.
Late Complications:
Scarring: potentially hypertrophic or keloid scars
Recurrence of symptoms: in cases of incomplete excision of a tumor or if symptoms were due to other causes
Chronic pain or dysesthesia
Psychological distress due to cosmetic deformity or functional deficits.
Prevention Strategies:
Meticulous surgical technique with careful identification and preservation of vital nerves and ducts
Adequate lighting and magnification
Use of electrocautery for hemostasis
Placing a drain to reduce seroma and hematoma formation
Patient education on postoperative care to prevent infection and promote healing
Careful patient selection and preoperative assessment.
Key Points
Exam Focus:
Anatomical landmarks are paramount: marginal mandibular nerve, lingual nerve, hypoglossal nerve, submandibular duct, mylohyoid muscle
Understanding the differential diagnosis of neck masses, particularly those in the submandibular region
Knowing the indications for excision versus conservative management
Recognizing and managing potential complications, especially nerve injuries.
Clinical Pearls:
To protect the marginal mandibular nerve, dissect along the inferior border of the mandible and retract the nerve
The lingual nerve is identified deep to the hyoglossus and superior to the duct
For deep lobe tumors, division of the mylohyoid muscle is often necessary
Always consider the possibility of malignancy, even with seemingly benign masses, and plan accordingly for potential oncological margins and lymph node assessment if indicated.
Common Mistakes:
Failure to adequately identify and protect the marginal mandibular nerve leading to postoperative lip droop
Incomplete division of the submandibular duct leading to salivary fistula
Injury to the lingual nerve causing taste and sensation deficits
Poor hemostasis leading to postoperative hematoma
Not considering malignancy as a differential diagnosis when indicated.