Overview
Definition:
Superficial parotidectomy is a surgical procedure to remove the superficial lobe of the parotid gland
It is commonly performed for benign and malignant tumors arising in this region
Intraoperative facial nerve monitoring is crucial to preserve facial nerve function.
Epidemiology:
Parotid gland tumors are the most common salivary gland neoplasms, accounting for approximately 80% of cases
Benign tumors are more frequent (70-80%), with pleomorphic adenoma being the most common
Malignant tumors are less common but require aggressive management.
Clinical Significance:
Accurate surgical resection with preservation of the facial nerve is paramount for both oncologic control and cosmetic/functional outcomes
Understanding the anatomy and potential complications is vital for surgical trainees preparing for DNB and NEET SS examinations.
Indications
Benign Neoplasms:
Pleomorphic adenoma
Warthin's tumor
Myoepithelioma
Benign lymphoepithelial lesions.
Malignant Neoplasms:
Low-grade mucoepidermoid carcinoma
Adenoid cystic carcinoma
Squamous cell carcinoma
Metastatic disease.
Inflammatory Conditions:
Recurrent parotitis unresponsive to medical management
Chronic sialadenitis with mass formation.
Diagnostic Biopsy:
When fine needle aspiration cytology is inconclusive or suspicious for malignancy.
Preoperative Preparation
History And Physical:
Detailed history of mass growth, pain, facial weakness, or neurological deficits
Palpation for mass characteristics, mobility, and involvement of surrounding structures
Examination of cranial nerves, especially facial nerve function.
Imaging:
Ultrasound of the parotid gland for initial assessment
CT scan or MRI with contrast is essential for tumor size, extent, relationship to the facial nerve, and involvement of adjacent structures
MRI is superior for soft tissue characterization.
Biopsy:
Fine needle aspiration cytology (FNAC) for suspected tumors to determine benign vs
malignant nature
Core needle biopsy may be used for specific indications.
Anesthesia Considerations:
General anesthesia with endotracheal intubation is typically required
Careful anesthetic management is needed due to the proximity of the airway and the need for prone positioning in some cases.
Surgical Procedure
Anesthesia And Positioning:
General anesthesia is administered
The patient is placed in a supine position with the head turned away from the side of surgery
A surgical head rest may be used.
Incision:
Preauricular incision, extending inferiorly and posteriorly along the sternocleidomastoid muscle
S-shaped incision is common to provide adequate exposure and facilitate closure.
Dissection And Nerve Identification:
Elevate skin flaps anteriorly and inferiorly
Identify the tragal pointer and the anterior border of the sternocleidomastoid muscle to locate the greater auricular nerve
Dissect along the superficial musculoaponeurotic system (SMAS) to identify the main trunk or branches of the facial nerve
Use nerve stimulator for identification and monitoring.
Gland And Tumor Excision:
Careful dissection around the identified facial nerve branches
Identify and ligate the external carotid artery and its branches supplying the gland
Excise the superficial lobe of the parotid gland with the tumor, ensuring adequate margins
If malignancy is suspected, wider margins are required.
Facial Nerve Monitoring:
Utilize intraoperative neuromonitoring (IONM) with a nerve stimulator and electromyography (EMG) to confirm facial nerve integrity during dissection
Stimulation of suspected nerve branches helps differentiate them from surrounding tissues and assess their functionality.
Hemostasis And Drainage:
Meticulous hemostasis is achieved using electrocautery and ligation of vessels
A surgical drain (e.g., Jackson-Pratt) is usually placed to prevent hematoma and seroma formation.
Closure:
Repair of SMAS layer if incised
Layered closure of subcutaneous tissue and skin
Drains are typically removed when output is minimal.
Postoperative Care
Pain Management:
Analgesics (opioids, NSAIDs) as needed
Monitor for signs of infection or complications.
Wound Care:
Keep incision clean and dry
Dressing changes as per protocol
Monitor for signs of wound dehiscence or infection.
Drain Management:
Monitor drain output
Remove when output is less than 20-30 ml/24 hours
Assess for potential complications like salivary leak.
Diet:
Soft diet initially, progressing as tolerated
Avoid very hot or spicy foods that may stimulate salivary flow and cause discomfort.
Facial Nerve Function Assessment:
Regular assessment of facial nerve function
Educate patient on potential temporary or permanent deficits and management strategies.
Complications
Early Complications:
Facial nerve injury (temporary or permanent weakness/paralysis)
Hematoma or seroma formation
Surgical site infection
Salivary fistula or leak
Bleeding.
Late Complications:
Frey's syndrome (gustatory sweating)
Facial asymmetry or contour deformity
Tumor recurrence (especially for malignant tumors)
Chronic pain.
Prevention Strategies:
Meticulous surgical technique with clear identification and monitoring of the facial nerve
Careful flap elevation
Adequate hemostasis
Use of drains
Prophylactic antibiotics
Patient education regarding postoperative care and potential sequelae.
Key Points
Exam Focus:
The key to superficial parotidectomy is identifying and preserving the facial nerve
Understanding the landmarks for nerve identification (e.g., tragal pointer, mastoid tip, digastric muscle) and the role of intraoperative neuromonitoring are high-yield for DNB/NEET SS.
Clinical Pearls:
Always dissect superficial to the facial nerve when approaching tumors in the superficial lobe
Remember that the facial nerve branches at the pes anserinus, deep to the retromandibular vein
In case of suspicion of malignancy, frozen section analysis of margins during surgery can be invaluable.
Common Mistakes:
Inadequate exposure leading to blind dissection near the nerve
Failure to identify the main trunk or key branches of the facial nerve
Inadequate margin clearance in malignant tumors
Not addressing Frey's syndrome preoperatively or postoperatively.