# Submandibular Gland Excision and Ranula Management

## Introduction

The **submandibular gland** is the second largest salivary gland and is commonly excised for obstructive disease, neoplasms, and chronic sialadenitis. Additionally, management of **ranulas** — mucoceles arising from the sublingual gland — is an important competency for the otolaryngologist. This lecture covers the surgical anatomy, indications, technique, and complications of submandibular gland excision and the workup and treatment of ranulas.

## Surgical Anatomy of the Submandibular Triangle

### Boundaries
**Superior**: inferior border of the mandible. **Anterior**: anterior belly of the digastric muscle. **Posterior**: posterior belly of the digastric muscle and stylohyoid muscle. **Floor**: mylohyoid and hyoglossus muscles.

### Key Neurovascular Structures
**Marginal mandibular branch of CN VII**: courses superficial to the facial artery and vein, deep to the platysma; at highest risk during surgery. **Lingual nerve**: courses in the floor of mouth, loops under Wharton duct (lateral to medial), and reascends to the tongue. **Hypoglossal nerve (CN XII)**: runs deep to the digastric tendon, superficial to the hyoglossus muscle. **Facial artery**: courses deep to the submandibular gland, wraps around the inferior mandibular border. **Facial vein**: superficial to the gland; often the first named vessel encountered.

### Wharton Duct
Approximately 5 cm long, Courses between the mylohyoid and hyoglossus muscles. Opens at the **sublingual caruncle** adjacent to the lingual frenulum. The lingual nerve crosses the duct twice (lateral to medial to lateral).

![Surgical anatomy of the submandibular triangle showing the marginal mandibular nerve, lingual nerve, and hypoglossal nerve](/images/submandibular-triangle-anatomy.jpg)

## Indications for Submandibular Gland Excision

**Sialolithiasis** refractory to conservative or sialendoscopic management. **Chronic sialadenitis** with gland fibrosis and recurrent infections. **Neoplasm** (benign or malignant) of the submandibular gland. **Excisional biopsy** for indeterminate masses. As part of **neck dissection** for head and neck cancer (Level IB dissection).

## Surgical Technique: Submandibular Gland Excision

### Preoperative Planning
Review imaging (CT, ultrasound, or MRI) for stone location, gland pathology, and lymph node status. FNA for any suspected neoplasm. Consent should include risks of marginal mandibular nerve injury, lingual nerve injury, and hypoglossal nerve injury.

### Procedure
**Incision**: 3-4 cm in a natural skin crease, approximately two fingerbreadths below the mandibular border. **Subplatysmal flaps** elevated superiorly and inferiorly. Identify and protect the **marginal mandibular nerve**: Hayes-Martin maneuver — ligate the facial vein and retract the nerve superiorly with the vein. Ligate the **facial artery** inferiorly and superiorly where it wraps around the gland. Dissect the gland off the **mylohyoid muscle**; retract the mylohyoid anteriorly to expose the deep portion of the gland and Wharton duct. Identify and protect the **lingual nerve** as it courses over Wharton duct. Identify and protect the **hypoglossal nerve** deep to the digastric tendon. Ligate and divide **Wharton duct** distally. Remove the gland and confirm hemostasis. Close in layers over a small suction drain.

![Intraoperative view demonstrating the Hayes-Martin maneuver with the marginal mandibular nerve retracted superiorly](/images/submandibular-excision-hayes-martin.jpg)

## Ranula: Pathophysiology and Classification

### Definition
A **ranula** is a mucous extravasation pseudocyst arising from the **sublingual gland** (or rarely a minor salivary gland) due to ductal injury or obstruction.

### Types
**Simple (oral) ranula**: confined to the floor of mouth; presents as a bluish, translucent, fluctuant swelling. **Plunging (cervical) ranula**: extends through or around the mylohyoid muscle into the submandibular or parapharyngeal space; presents as a neck mass. The mylohyoid muscle has a natural **posterior free edge (boutonniere)** through which mucus can herniate.

## Ranula Management

| Treatment | Ranula Type | Recurrence Rate | Notes |
|-----------|-------------|-----------------|-------|
| Observation | Small simple | Variable | May resolve spontaneously |
| Marsupialization | Simple | 60-90% | High recurrence; not definitive |
| Sublingual gland excision (transoral) | Simple or plunging | <2% | Definitive treatment of choice |
| OK-432 (picibanil) injection | Simple | Variable | Sclerosing agent; less invasive |
| Combined transoral + transcervical | Large plunging | Low | For extensive cervical extension |

### Simple Ranula
**Observation**: small ranulas may resolve spontaneously. **Marsupialization**: incision and suturing of the cyst wall to the floor of mouth mucosa; recurrence rate 60-90%. **Excision of the sublingual gland**: definitive treatment; recurrence rate <2%. Injection of **OK-432 (picibanil)**: sclerosing agent with variable success.

### Plunging Ranula
**Excision of the sublingual gland** via a transoral approach is the definitive treatment. Cervical drainage alone has a high recurrence rate. Combined transcervical and transoral approach may be necessary for large plunging ranulas. Imaging (CT or MRI) is essential to define the extent of the plunging component.

![Clinical photograph of a simple ranula presenting as a blue-domed, translucent swelling in the floor of mouth](/images/simple-ranula-clinical.jpg)

## Complications

### Submandibular Gland Excision
**Marginal mandibular nerve injury**: temporary in 5-10%, permanent in 1-2%; causes lower lip asymmetry with smiling. **Lingual nerve injury**: numbness and loss of taste to ipsilateral tongue. **Hypoglossal nerve injury**: ipsilateral tongue deviation (rare). **Hematoma**: may require evacuation. **Wound infection**: uncommon.

### Ranula Surgery
**Recurrence**: highest with marsupialization alone; lowest with sublingual gland excision. **Lingual nerve injury**: at risk during sublingual gland excision. **Wharton duct injury**: must be identified and protected during sublingual gland removal.

## Key Clinical Pearls

The **marginal mandibular nerve** is the structure most at risk during submandibular gland excision; the Hayes-Martin maneuver is essential for protection. In up to 20% of patients, the marginal mandibular nerve dips below the mandibular border, making it vulnerable with low incisions. A **plunging ranula** should be treated by excising the sublingual gland, not by draining the cervical component alone. Always identify the **lingual nerve** before dividing Wharton duct during submandibular gland excision. When performing sublingual gland excision for ranula, identify and protect both the lingual nerve and Wharton duct.

## References

1. Patel MR, Deal AM, Shockley WW. Oral and plunging ranulas: what is the most effective treatment? *Laryngoscope*. 2009;119(8):1501-1509.
2. Preuss SF, Klussmann JP, Wittekindt C, et al. Submandibular gland excision: 15 years of experience. *J Oral Maxillofac Surg*. 2007;65(5):953-957.
3. Zhao YF, Jia Y, Chen XM, Zhang WF. Clinical review of 580 ranulas. *Oral Surg Oral Med Oral Pathol Oral Radiol Endod*. 2004;98(3):281-287.
4. Hanna BC, Brooker DS, Givan FK. Submandibular gland excision: a review of 100 consecutive cases. *Ir J Med Sci*. 2008;177(3):231-234.