Supraomohyoid Neck Dissection Treatment & Management

Updated: Aug 19, 2021
  • Author: Antonio Riera March, MD, FACS; Chief Editor: Arlen D Meyers, MD, MBA  more...
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Treatment

Surgical Therapy

Supraomohyoid neck dissection involves resection of LN groups localized in levels I-III.

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Preoperative Details

Consider and evaluate the following, taking careful documentation:

  • Results of physical examination (including head and neck findings)

  • Medical history (eg, medication allergies; hypertension, diabetes mellitus, cardiopulmonary disease, and other chronic illnesses; previous surgeries; radiation therapy)

  • Medical clearance and recommendations

  • All test results, including those of biopsy and FNAB

  • Informed consent, with risks and complications fully discussed with the patient

  • Summarized problem and treatment plan, including alternatives plans

  • Airway and dentition of the patient

  • Patient's ability to open the mouth enough for intubation

Additionally, if the patient undergoes a tracheotomy, evaluate its status and that of the airway. On the day of surgery, patients should remain on nothing by mouth (NPO) status after midnight the night before. Patients may be administered usual medications up to midnight before the surgical procedure. Note premedication order on record. Void on call to the operating room. Preoperative antibiotics are required if the procedure involves passage through the neck into the upper aerodigestive tract.

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Intraoperative Details

If the airway is obstructed, performing a tracheotomy with the patient under local anesthesia is preferred. Obstructing neoplasms of the upper aerodigestive tract can bleed easily at intubation, which produces a sudden, total obstruction in an already compromised airway. Prevention and planning are mandatory.

If the airway is unobstructed, the anesthesia service can perform an orotracheal or nasotracheal intubation.

In a difficult but not obstructed airway, the anesthetist may perform an awake intubation with the assistance of a flexible nasopharyngolaryngoscopy to accomplish a nasotracheal intubation.

Airway compromise or marginal compromise is not uncommon in patients with head and neck cancer. Therefore, good communication and understanding between the surgeon and the anesthetist is essential.

A Foley catheter is unnecessary during supraomohyoid neck dissection. If the surgery is performed with other procedures that are more complex and prolonged, a Foley catheter is inserted for better control of urine output. Place the patient in the supine position with a shoulder roll to extend the neck. Elevate the upper half of the operating table to a 30° angle. Prepare and drape the patient's neck and upper chest; use staples or sutures to delineate the field. Notify the anesthesia service that the patient cannot be paralyzed during the surgical procedure.

Supraomohyoid neck dissection

Mark the skin incision with methylene blue or a surgical marking pen. Some authors infiltrate the skin incision with 10 mL of lidocaine with 1:100,000 epinephrine to minimize bleeding. (The author's institution does not follow this practice.)

The skin incision varies depending on whether the operation is on a single side of the neck or on both sides and whether the lip needs to be split for access to the oral cavity. Use scratch marks to assist in alignment of flaps at the end of the operation. If an ipsilateral supraomohyoid neck dissection is planned, make a modified apron incision to provide adequate exposure. If bilateral neck dissection is planned, carry the horizontal component across to the other side of the neck. Both of these incisions are adequate for a pull-through operation.

When splitting the lip is essential for exposure into the oral cavity, the unilateral inverted hockey stick incision and the bilateral inverted hockey stick incision, as seen in the image below, are necessary.

Bilateral inverted hockey stick incision. This ski Bilateral inverted hockey stick incision. This skin incision is ideal for a wide exposure of all levels of nodes in both sides of the neck. The skin incision is made through the platysma, and the flap is elevated in the subplatysmal plane, leaving the external jugular vein (EJV) and the greater auricular nerve on the sternocleidomastoid (SCM) muscle. Elevation posterior to the SCM muscle is unnecessary. The subplatysmal flap is elevated to the level of the body of the mandible. The marginal mandibular nerve is identified (circle).

The reverse bilateral hockey stick incision is ideal for a wide exposure of all levels of nodes in both sides of the neck. Make scratch marks to assist in alignment of the flaps at the end of the operation.

Make the skin incision through the platysma and elevate the flap in the subplatysmal plane, leaving the external jugular and greater auricular nerve on the SCM muscle. Traction with the surgeon's fingers and countertraction by the assistant with 2 double skin hooks are helpful in this maneuver. Elevation posterior to the SCM muscle is unnecessary. Elevate the subplatysmal flap to the level of the body of the mandible for evaluation of tumor extension. Some surgeons proceed from posteroinferior to anterosuperior; others do the opposite. The author's institution usually proceeds with level I dissection.

The marginal mandibular nerve is identified, elevated, dissected (free from the surrounding tissue), and preserved. Remove the submental fatty tissue with Bovie electrocautery and displace it inferiorly. This reveals the anterior belly of the digastric muscle. Retract and elevate the mylohyoid muscle anteriorly, exposing the submandibular ganglion, lingual nerve, and submandibular duct. Clamp, divide, and ligate the submandibular duct. Ligate the facial artery above the digastric muscle. Careful dissection avoids injury to the hypoglossal and lingual nerves, which are located deep to the fascia on the floor of the submandibular triangle.

Remove the submandibular nodes and the submandibular gland and displace them inferiorly as seen in the image below. As the gland is reflected posteroinferiorly, the facial artery is reencountered and can be ligated. Identify and completely expose the posterior belly of the digastric muscle. level I dissection is completed at this point.

The submental fatty tissue, submandibular nodes, a The submental fatty tissue, submandibular nodes, and submandibular gland are dissected and displaced inferiorly. The mylohyoid muscle is retracted and elevated anteriorly. The anterior belly of the digastric muscle is exposed.

The fascia over the SCM muscle and the ligated EJV are grasped and peeled from the muscle as seen in the image below. The greater auricular nerve is sacrificed in the process of the dissection; however, some surgeons claim preservation. Grasp the fascia with Allis clamps and pull vertically. Using electrocautery, peel the fascia from the SCM muscle. Assistance with traction and countertraction is necessary for this stage. Sharp dissection with a knife also suffices for fascial peeling. Vessels that enter the muscle can be cauterized with a bipolar forceps for hemostasis.

The fascia over the sternocleidomastoid (SCM) musc The fascia over the sternocleidomastoid (SCM) muscle, along with the ligated external jugular vein (EJV), is grasped and peeled from the muscle. The accessory nerve is localized in the upper portion of the SCM muscle during the peeling maneuver.

Next, identify the accessory nerve. (This can be accomplished if the patient is not paralyzed and electrocautery is used.) Dissection with an intermediate hemostat placed 2-3 finger breadths below the posterior belly of the digastric muscle, at the point where the accessory nerve enters the SCM muscle, (as seen in the image below) encounters the nerve directly with sight or indirectly with stimulation. Retraction of the SCM muscle and the posterior belly of the digastric muscle is imperative in this maneuver. After identification of the accessory nerve, it can be traced to the posterior belly of the digastric muscle.

View of the upper portion of the sternocleidomasto View of the upper portion of the sternocleidomastoid (SCM) muscle and the accessory nerve during dissection.

Elevate the nerve after dividing the tissue lateral to it. Remember that the nerve is lateral to the IJV in approximately 70% of individuals, as seen in the image below. Therefore, in one third of patients, the accessory nerve passes medial to the IJV and can be traumatized by any technical error. Place attention on the posterior corner formed by the posterior belly of the digastric muscle and the SCM muscle, which are retracted. Retraction is critical in this particular area. Using a Bovie electrocautery unit, grasp the fibroadipose tissue inside the posterior corner with an Allis clamp and retract and dissect inferiorly until the underlying deep cervical muscles are revealed. Pass the fibrofatty tissue under the accessory nerve.

A close view of the relationship between the acces A close view of the relationship between the accessory nerve and the upper portion of the internal jugular vein (IJV). In one third of patients, the accessory nerve passes medial to the IJV.

The dissection continues inferiorly with incision of the fibroadipose tissue along the posterior border of the SCM muscle to the level of the omohyoid muscle. When the sensory branches of the cervical plexus are found, the dissection continues in a plane lateral to these nerves. At this point, intraoperative evaluation is extremely important to determine if levels IV and V also must be addressed.

Following the sensory branches of the cervical plexus expedites rolling over the carotid artery from posterior to anterior. If performed incorrectly, in a deeper layer, the dissection runs under the plane of the carotid sheath and IJV. Avoid injury to any of these structures. Being in the right plane is crucial. Watch for the cervical plexus and the phrenic and vagus nerves.

Identify the carotid sheath and vagus nerve as depicted in the images below.

The carotid sheath and vagus are identified. The n The carotid sheath and vagus are identified. The node-containing tissue is peeled over the carotid axis in an inferior-to-superior direction. Rolling over the fascia of the internal jugular vein (IJV) is best performed using a sharp knife with a No. 10 surgical blade. Traction and countertraction are crucial.
View of the upper and midportion of the sternoclei View of the upper and midportion of the sternocleidomastoid (SCM) and the accessory nerve (rectangle) during dissection. The carotid sheath (C) and the internal jugular vein (IJV) are seen in the picture.
The sternocleidomastoid muscle (SCM) is retracted. The sternocleidomastoid muscle (SCM) is retracted. The carotid sheath (C), the vagus (V), and the accessory nerve (rectangle) are identified. The node-containing tissue is peeled over the carotid axis in an inferior-to-superior direction. The peeling of the nodal tissue over the internal jugular vein (IJV) has been partially done in the picture. Traction and countertraction are crucial during the peeling maneuver.

Sharply cut the node-containing tissue above an intermediate hemostat; roll over the carotid axis in an inferior-to-superior direction. Peel the fascia over the IJV. This is best accomplished using a sharp knife with a No.10 surgical blade, cutting with its belly over the vein (in the interface between the fascia and the vein) using gentle traction and countertraction. This particular technique should be taught and discussed with residents in their first cases. Another way to dissect the IJV is to use a vascular forceps with the assistance of scissors, hemostat, or both.

Ligate the tributary veins with 3-0 silk, since fasciae over the IJV are unfolded. Occasionally, the common facial vein must be divided; this is accomplished by preserving a stump of the IJV to avoid a narrowing of the main vein. Follow the superior belly of the omohyoid muscle to the hyoid bone. Divide and ligate the ranine veins. Preserve the superior thyroid artery and the hypoglossal nerve. Continue until the dissection posteriorly reaches anteriorly. Complete the dissection at this point by removing the specimen.

In the last year, the use of the harmonic scalpel in the execution of the supraomohyoid neck dissection has been introduced. [19, 20] Its progressive use has displaced most other, more conventional, intraoperative techniques used for providing hemostasis, such as clamping, tying, and electrocauterization. The major advantage is shortening of the operative time.

Resection of the primary lesion follows. In the image below, the final aspect of the surgical wound after removal of the operative specimen is seen. Irrigate with isotonic sodium chloride solution at the end of the operation. Maintain hemostasis. Insert 0.125-in Hemovac or Jackson-Pratt drains, usually 2 for each side of the neck.

The final aspect of the surgical wound after remov The final aspect of the surgical wound after removal of the operative specimen.

Table 1. Surgical Steps in Supraomohyoid Neck Dissection (Open Table in a new window)

Procedure Step

Surgical Steps and Pearls

Supraomohyoid neck dissection/definition

It is also called anterolateral neck dissection.

It consists of removal of cervical lymphatic nodes contained in neck levels I, II and III.

It is generally used as a selective neck dissection in patients with squamous cell carcinoma of the oral cavity, T1-T4 and N0, if the primary lesion is not to be treated with radiation therapy. In this manner, the supraomohyoid neck dissection is both diagnostic and therapeutic.

In the N+ neck, standardization is lacking; see text for a detailed description of indications and contraindications.

Incision design

Try not to use trifurcation incisions.

The recommended incisions for unilateral neck dissection are the modified apron incision or the inverted hockey stick incision.

The recommended incisions for bilateral neck dissection are the apron incision or the bilateral inverted hockey stick incision.

Skin incision and skin and subplatysmal flap elevation

Elevate the skin and subplatysmal flap to the level of the body of the mandible.

Expose the anatomy of the submandibular, submental, and carotid triangles.

Leave the external jugular vein and the greater auricular nerve on the SCM muscle.

Elevation posterior to the SCM muscles is unnecessary.

level I dissection

Identify the mandibular nerve and elevate it, along with the surrounding tissue, in its own plane.

Remove the submental fatty tissue and identify the anterior belly of the digastric muscle.

Follow the anterior belly of the digastric muscle and identify the mylohyoid muscle.

Retract anteriorly the mylohyoid and expose the submandibular ganglion, lingual nerve, and submandibular duct. Divide and ligate the submandibular duct.

Clamp, divide, and ligate the facial artery.

Remove the submandibular gland and the submandibular lymph nodes.

Identify the hypoglossal nerve deep into the fascia of the submandibular triangle.

Identify and expose completely the posterior belly of the digastric muscle up to the mastoid tip.

If the facial artery is reencountered at this point, tie it and ligate it.

After completion of all of the above, dissect and displace inferiorly the submental fatty tissue, submandibular nodes, and submandibular gland.

Fascial peeling of SCM

Ligate the external jugular vein.

Grasp the fascia over the SCM and peel it from the muscle.

The accessory nerve is encountered in the upper portion of the SCM during the peeling maneuver. Identify the accessory nerve directly by sight or indirectly with nerve stimulation.

Dissection posterior and inferior to the SCM

Continue inferiorly the dissection of fibroadipose tissue along the posterior border of the SCM muscle to the level of the omohyoid muscle.

Identify and follow the sensory branches of the cervical plexus and continue the dissection lateral to these nerves.

Follow the sensory branches of the cervical plexus from posterior to anterior in order to reach the carotid sheath.

Identify and protect the cervical plexus and the phrenic and vagus nerves.

Carotid sheath, vagus nerve, internal jugular vein

Identify the carotid sheath, the vagus nerve, and the internal jugular vein.

Unwrap the carotid sheath, freeing it of tissue containing nodes, working in an inferior to superior direction.

Identify the vagus nerve and preserve it.

Do the same with the internal jugular vein.

Identify, clamp, and ligate the branches of the internal jugular vein.

Completion and removal of specimen

Follow the superior belly of the omohyoid muscle to the hyoid bone.

Divide and ligate the ranine veins.

Identify and preserve the superior thyroid artery and the hypoglossal nerve.

Complete the dissection at this point by removing the specimen.

Wound closure

Use 3-0 Vicryl through the platysmal flaps and staples or 4-0 nylon for the skin. No compressive dressings are used for bilateral neck dissections; however, some surgeons use a compression dressing for unilateral neck dissection.

Pathology specimen

Plastic plates with a life-size drawing of the different neck areas are recommended for orientation. Place the unfixed specimen as it appears in the patient and transfer to the pathology department from the operating room. The type of dissection performed should be clearly indicated on the requisition slip.

Surgical technique modification

The main difficulty in the learning process for the head and neck surgeon is neck orientation. Tridimensional and depth perception in the different planes are difficult to master. Therefore, the authors have found that the learning process is easier if the resident can approach the supraomohyoid neck dissection from 2 different angles that meet at the exposed carotid-jugular axis. The exposure and identification of the carotid-internal jugular axis helps the resident to understand depth perception in the different planes. In other words, complete level I first and displace it inferiorly, which exposes both bellies of the digastric muscle. Then, expose the anterior belly of the omohyoid, and, from above, dissect the carotid triangle below the digastric muscle.

Carefully ligate the ranine veins. Preserve the superior thyroid artery and the superior laryngeal nerve. The plane of the carotid-internal jugular axis is identified anteriorly. The surgical technique is depicted in the image below.

Surgical technique modification. The level I disse Surgical technique modification. The level I dissection is completed first and displaced inferiorly. The carotid triangle is then dissected. The ranine veins are carefully ligated. The superior thyroid artery and the superior laryngeal nerve are preserved. The exposure and identification of the carotid-internal jugular axis help in understanding the depth perception in the different planes (arrow 1). The dissection then proceeds as described previously from lateral to medial (arrow 2).

As described previously, dissection then proceeds from lateral to medial as seen in the image below.

Surgical technique modification. Exposure and iden Surgical technique modification. Exposure and identification of the carotid-internal jugular axis has been accomplished. Finally, the dissection proceeds in the usual fashion, from lateral to medial, until the entire specimen is removed.

Current Procedural Terminology code (CPT coding)

38724, Supraomohyoid Neck Dissection (same code used for extended supraomohyoid neck dissection)

Endoscopic and robotic neck dissections

Minimally invasive surgery with the assistance of endoscopic and robotic instrumentation has been tried in head and neck cancer management, including neck dissection for cervical metastatic disease. [21, 22] The viability of neck dissection has been demonstrated using this armamentarium; however, its oncological application in the management of neck metastasis versus the classic open approach remains to be seen.

Supraomohyoid neck dissection in the clinically N0 neck has been also tried using endoscopic and robotic instrumentation with better cosmetic results and similar oncological effectivity. [23]

Further assessment and follow-up are needed prior to the use of endoscopic and robotic dissections in routine oncological practice.

Other associated surgeries

Bilateral supraomohyoid neck dissection does not require tracheotomy. Other surgeries directed to the primary tumor vary according to size and location of the tumor. The patient may need a tracheotomy to control the airway, depending on the amount of tissue resected at the primary site, type of reconstruction, and the need to maintain the airway patent in the immediate postoperative period.

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Postoperative Details

See the list below:

  • Maintain NPO status for at least the first 24 hours postoperatively.

  • Most patients have a nasogastric tube (NGT). Start feeding through the NGT on a schedule corresponding to the patient's condition and tolerance.

  • Maintain head elevation at a 30° angle.

  • Monitor vital signs, intake, and output every 4 hours.

  • Administer pain medications as needed.

  • Ensure that Hemovac suction tubes or drains function properly.

  • Ensure that drains are maintained continuously on suction and that they do not clot.

  • Maintain drains until they drain less than 20-25 mL in 24 hours.

  • Administer antibiotics for 24 hours if the surgery involved opening the neck and the upper aerodigestive tract.

  • Monitor for fever, bleeding, or hematoma in the postoperative period.

  • Avoid atelectasis. Encourage deep breathing and early ambulation with assistance.

  • Monitor for possible fistula if the oral or upper digestive tract was opened, particularly during postoperative days (PODs) 3 and 4.

Discharge criteria

See the list below:

  • Shoulder physical therapy has been ordered if needed.

  • Drains have been removed (usually on POD 4 or 5).

  • The surgical wound has healed satisfactorily.

  • No evidence of bleeding or infection has been observed.

  • Adequate airway and nutrition have been achieved.

  • Hemodynamic stability has been achieved.

  • Adequate family or home care support has been arranged.

  • If other surgical procedures were performed in addition to supraomohyoid neck dissection, the discharge day varies according to the progress and condition of the patient.

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Follow-up

See the list below:

  • Call the patient at home to check the patient's condition.

  • Arrange for the patient to return to clinic (RTC) in 7-10 days. Check the pathology report for complete resection and free margins. Check the pathology status of the neck. Evaluate for further consultations and adjunctive treatment as needed.

  • Remove sutures or clips at 7-14 days. When radiation therapy has been administered, sutures or clips should remain in place for at least 10 PODs.

  • If necessary, continue with shoulder physical therapy.

  • Follow-up care is mandatory to check for recurrent tumor or development of a second primary tumor. Therefore, see the patient every month for the first year, particularly if no primary lesion was initially found. Thereafter, see the patient every 2-4 months for up to 5 years. After this interval, the patient can be seen yearly.

  • Advise the patient to call for an immediate appointment if the patient's condition suddenly changes.

  • For excellent patient education resources, see eMedicineHealth's patient education article Cancer of the Mouth and Throat.

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Complications

When the supraomohyoid neck dissection is performed without opening the oral cavity or aerodigestive tract, major complications are unlikely.

However, previous radiation therapy is associated with a high complication rate. Other factors, such as poor general health, chronic malnutrition, alcoholism, diabetes mellitus, advanced age, and systemic illness, increase the percentage rate of complications.

Intraoperative complications

See the list below:

  • Hemorrhage

    • Severe blood loss is an uncommon complication for an experienced head and neck surgeon. The average blood loss in the realization of a selective neck dissection is 200 mL or less. This amount varies slightly according to the surgical technique and the surgeon. Careful attention to anatomy, hemostasis with an electrocautery unit or bipolar forceps, and use of clamps and suture ligation has allowed an almost bloodless neck operation. The recent addition of the harmonic scalpel in the armamentarium has allowed a significant shortening of the operative time. [19, 20]

    • Today, major vessel trauma, laceration, tear, or transection (eg, IJV, junction of IJV and subclavian and/or carotid arteries) is a rare occurrence. Immediately repair injury to the carotid arteries. Consultation with a vascular surgeon may be useful depending on intraoperative findings. A small tear or laceration requires primary closure with a 6-0 continuous vascular suture. Other injuries may require ligation or reconstruction. Injury to the IJV at the upper or lower ends can be a serious problem.

    • If the lower end of the jugular vein bleeds excessively, pressure is the first aid, followed by adequate visualization and suctioning until the stump is identified, dissected, and ligated properly. Infrequently, bleeding cannot be controlled and requires the assistance of a thoracic surgeon to enter the superior mediastinum.

    • If the distal end of the vein bleeds excessively and the stump has retracted into the temporal bone, packing the jugular foramen with large pieces of Surgicel, plicating with the posterior belly of the digastric muscle, or both suffices to solve the problem.

    • In most instances, injury along the axis of the IJV is less problematic. Small fissures of the IJV are rare when the scalpel blade is used (understanding the technique is necessary), and the fissures usually stop bleeding with gentle pressure or with a tiny suture ligation using 3-0 silk (while holding the break with the tip of the small hemostat). On the few occasions when the vein is torn, it can be salvaged using a 6-0 vascular suture.

  • Carotid sinus reflux: Hypotension due to carotid sinus reflux may occur upon dissection around the carotid bifurcation. Temporarily, this situation can be avoided by careful dissection at this level without manipulation, injection of 2 mL of local anesthetic into the adventitia at the carotid bifurcation between the internal and external carotid arteries, or both.

  • Pneumothorax

    • Pneumothorax involves a sudden compromise of the respiratory and circulatory system and manifests as difficult breathing, bronchospasm, and decrease in oxygen saturation. The pressure of the anesthetic bag does not cause normal expansion of the thorax.

    • Pneumothorax is rare today. To minimize chances of this complication, carefully dissect in the paratracheal area and base of the neck with good hemostasis, adequate visualization, and precise dissection of the tissues close to the apex of lung.

    • If the pneumothorax is small, the wound can be closed with an airtight seal. Follow-up with conservative management controls the situation without sequelae. However, a large pleural leak with a tension pneumothorax requires immediate aspiration with a No. 14 or No. 16 needle in the upper anterior thorax, placement of a chest tube with an underwater drainage, or both.

  • Air embolism

    • Air embolism is also rare today. This complication can occur when a large vein is inadvertently opened. A large volume of air rapidly enters the open vein by negative pressure and passes directly into the right atrium, causing a sudden alteration of the central circulation, which leads to tamponade of the heart and even death.

    • Clinically, cyanosis, hypotension, and a loud churning noise over the precordial area suddenly manifest, and the peripheral pulse disappears. Treatment requires immediately packing or clamping the offending vein and turning the patient onto the left side with the head down. Cardiac arrest can occur, requiring aspiration of the air from the heart, massage, and standard resuscitation procedures. Prevention, with careful identification and clamping of the major veins of the neck, is best. Adequate ligations and transfixion sutures are mandatory.

  • Embolism: Embolism leading to stroke can occur. Most patients with cancer are of the age at which arterial cerebrovascular disease is common. Careful handling of the carotid arterial system in the neck with gentle retraction, ligation, and manipulation prevents dislodgment of arteriosclerotic plaques from the internal carotid system.

  • Nerve damage

    • The neck area has multiple sensory nerves that are sacrificed during supraomohyoid neck dissection. Therefore, loss of sensation occurs in multiple areas (eg, neck, posterior occiput, external ear, mandibular region, lateral shoulder, deltoid area, upper pectoral area). Occasionally, the formation of a neuroma at the end of a cut nerve may cause paresthesias and pain.

    • The ramus mandibularis is preserved in most neck dissections unless it is involved by metastatic disease. The transection of the marginal mandibular branch of the facial nerve produces lower lip weakness. If the tail of the parotid is resected, follow the nerve into the parotid tissue before removal of this tissue. Sacrifice of the cervical sympathetic chain produces Horner syndrome, which involves ptosis, anhidrosis, and miosis.

    • The spinal accessory nerve is preserved in the supraomohyoid neck dissection. However, damage to the nerve by stretching or devascularization produces shoulder dysfunction, limitation in the range of motion of the arm and shoulder, and local pain in the affected area. Most patients tolerate this disability well and improve markedly with physical therapy within 1 year.

    • Unilateral resection of the hypoglossal nerve is usually well tolerated without serious sequelae; however, bilateral hypoglossal nerve resection causes severe disability with serious difficulties in feeding, swallowing, and speaking. A feeding gastrostomy tube is sometimes recommended for adequate nutrition.

    • Damage in the lower or middle neck to the vagus nerve, which carries motor and sensory branches to the larynx and pharynx, causes vocal cord paralysis. Damage to the brachial plexus is rare in the supraomohyoid neck dissection and can be avoided by proper identification of anatomic planes. If damage occurs, reapproximate the sectioned brachial plexus with 8-0 or 9-0 nylon monofilament or silk.

  • Poor wound healing after radiation therapy: Patients who have received radiation therapy before supraomohyoid neck dissection tend to have increased postoperative complications such as wound infection, fistula, flap necrosis, osteoradionecrosis, and carotid artery rupture. Few institutions reserve surgery for salvage after radiotherapy failure in the treatment of cancer of the head and neck.

  • Chylous fistula: Chylous fistula is a rare complication of supraomohyoid neck dissection that may occur during dissection of the thoracic duct region. Most chylous fistulas occur on the left side. If a chylous fistula is found, ligate the thoracic duct. Reinspect the area before completing the surgery. Ask the anesthesiologist to apply positive pressure to determine if further leaking is present. A small leak can be identified with assistance of the microscope. Ligation is mandatory. A suture ligation with a figure 8 using 4-0 silk is usually satisfactory. Hemostat clips have also been used when the leakage is clearly visualized.

Postoperative complications

See the list below:

  • Hematoma

    • Meticulous hemostasis during the surgical procedure is mandatory. Use suction drains to avoid accumulation of blood under the skin flap and to prevent hematoma formation.

    • Some surgeons also use a floppy, moderately compressive dressing in addition to the suctioning system mentioned above. This is disadvantageous because the compressive dressing leaves flaps unavailable for inspection, which is the best way to monitor for hematoma formation.

    • A hematoma usually manifests in the first few postoperative hours. Sudden bleeding in the postoperative period indicates that an untied vessel has opened or that a ligature has slipped from the vessel. Blood under the flap accumulates rapidly. Treat by opening and elevating the neck flaps to evacuate the hematoma. Irrigate the surgical field with isotonic sodium chloride solution, and, if any source of bleeding is found, ligate, suture, or electrocauterize to achieve hemostasis. If the hematoma is recognized and treated early, no adverse consequences ensue. However, if found late, airway compromise, infection, or flap necrosis can occur.

  • Wound infection

    • When supraomohyoid neck dissection is performed without opening the oral cavity or aerodigestive tract, wound infection is unlikely. However, the potential for wound infection increases markedly when supraomohyoid dissection is performed in combination with the opening of the oral cavity as part of a composite resection. Salivary contamination from the oral cavity is possible, causing bacterial invasion and wound infection.

    • All irradiated tissues are more susceptible to infection because of ischemia and hypoxemia. Other factors that increase possibilities of wound infection are malnutrition, chemotherapy, anemia, diabetes mellitus, and advanced tumor mass.

    • If wound infection develops, open the flap, evacuate and culture the pus, and irrigate the wound. Administer antibiotics that cover gram-positive and gram-negative organisms. Carefully debride necrotic tissue. Local care with frequent dressing changes, salivary fistula control, and wound irrigation is critical. Once the infection is under control and necrotic tissue is removed, healthy granulation tissue appears.

  • Skin flap loss

    • Skin flap necrosis can have several causes, such as design errors, elevation, poor handling, or improper postoperative care. Preexisting scars, prior radiation therapy, hematoma, infection, and poor nutrition can contribute to skin flap loss. If skin flap necrosis occurs and the carotid is not exposed, a conservative approach is mandatory. Carefully and progressively trim necrotic tissue and frequently change wound dressings.

    • In the supraomohyoid neck dissection, the carotid artery is covered by the SCM muscle. Therefore, carotid exposure is unlikely unless major tissue necrosis and skin loss occurs.

    • Skin necrosis, infection, and accumulation of pus adjacent to the carotid wall alert the surgeon to a potential carotid artery rupture. Management is on a patient-by-patient basis; however, initially, control of infection, wound cleansing, and local care are priorities. The decision between flap coverage and secondary healing is then made.

  • Salivary fistula

    • Salivary fistula occurs more frequently when a patient previously has received radiation therapy and the oral cavity, pharynx, or cervical esophagus has been opened in association with the neck dissection.

    • Good surgical technique with double-layer closures and watertight closures without tension minimize this complication. Use Vicryl or Dexon sutures in high-risk patients. Low-suction drainage is recommended; do not place Hemovac drains over carotid arteries.

    • Usually, the fistula appears within 4-5 days of surgery; however, fistulas can develop after an interval of 2-3 weeks, particularly after irradiation. Fistulas may range from a small leak that is well managed by conservative measures (eg, frequent dressing changes, local care) to a large leak that involves infection of the whole neck with flap necrosis. Patients with large leaks require enteral or parenteral feeding, controlled exteriorization of the fistula, and local care before closure of local skin or myocutaneous flaps.

  • Chylous fistula: Chylous fistula is rare in supraomohyoid neck dissection. Chyle can be identified by a milky appearance in the Hemovac tubes. Chyle accumulation under the flap can cause redness and swelling of the flap with induration of the surrounding tissues. If the leak is minimal, it usually can be controlled by aspiration, pressure dressings, and a low-fat diet. Ligation of the offending thoracic duct is required when the leak is extensive (ie, >500 mL of drainage for 5 d without improvement with conservative management).

  • Facial edema: Facial edema can occur even if a single IJV remains, particularly in patients with previous irradiation therapy. Edema reaches a maximum at POD 7 and progressively decreases in a few weeks with conservative management. Facial edema is increased with synchronous bilateral radical neck dissections.

  • Electrolyte disturbances: The most common electrolyte disturbance in the postoperative period is hyponatremia. Although usually dilutional, this condition can be related to inappropriate antidiuretic hormone secretion. Clinically, hyponatremia can manifest as mental changes, including depression and hallucinations. Occasionally, hypernatremia, hypokalemia, hypercalcemia, and hypophosphatemia are also associated with neck operations.

  • Carotid artery rupture

    • Carotid artery rupture is rare after supraomohyoid neck dissection. Incidence of this complication ranges from 3-7%. The precipitating factors of carotid artery rupture are as follows:

      • Radiation therapy

      • Infection and salivary fistula

      • Suction catheters that cause erosion of the vessel wall

      • Exposure by dehiscence of the suture line or necrosis of the dermis

    • Rupture occurs in patients who underwent neck surgery with exposure of the carotid artery and one or more of the precipitating factors listed above. Most patients have prodromal bleeding (ie, sentinel bleed) within 48 hours of carotid artery rupture. Therefore, initial bleeding indicates that serious complications can be avoided with elective ligation of the offending artery. Immediate treatment for carotid artery rupture includes the following measures:

      • Apply direct and firm pressure to the affected area. Prepare the operating room for neck surgery. Suctioning, good illumination, and adequate instrumentation are imperative.

      • With a large-bore catheter, cannulize a peripheral vein in each arm for immediate administration of fluids (eg, Ringer lactate, isotonic sodium chloride solution). Controlling blood pressure and blood volume before ligation is important.

      • The airway should be adequate and stable. If the patient does not undergo a tracheotomy, orotracheal intubation may be necessary.

      • Blood is typed and cross-matched for 4-6 units of blood.

      • Move the patient to the operating room.

      • If bleeding cannot be controlled with pressure, clamp the common carotid artery as an emergency procedure after blood pressure and pulse are within the reference range.

    • Definitive treatment for carotid artery rupture includes the following measures:

      • Ligate the carotid artery. Avoid repair or diversion in infected areas.

      • Use general endotracheal anesthesia.

      • Ensure adequate instrumentation is prepared.

      • Adequate exposure (both proximally and distally) to the source of bleeding and contaminated or infected areas helps prevent a second rupture.

      • Accomplish ligation with 1-0 silk suture. Reinforce this suture, distally and proximally, with 2-0 silk suture. Then, bury the ligated stump in surrounding healthy tissue.

      • Occasionally, ligating the carotid artery beneath the clavicle is necessary. Resection of the medial half of the clavicle is necessary for exposure if the ligation must be performed inferior to the supraclavicular triangle.

    • Prophylaxis for carotid artery rupture includes the following measures:

      • Do not traumatize the carotid vessel. Careful handling of the carotid artery and preservation of the adventitia are most important.

      • Avoid suction catheters that lie adjacent to the carotid artery.

      • If a fistula is present, divert it from the carotid area.

      • Use adequate dressings that retain moisture.

      • Cover the carotid artery with a dermal graft using the levator scapulae muscle or posterior scalene muscle.

      • Aggressively treat infection with drainage, culture, and appropriate antibiotics.

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Outcome and Prognosis

Supraomohyoid neck dissection, with the primary tumor under control, has resulted in recurrence rates as follows:

  • In a neck with negative histologic findings, the recurrence rate is 4-6%.

  • In a neck with single node metastasis without capsular spread, the recurrence rate is 10%.

  • In a neck with multiple node metastasis or extracapsular spread, the recurrence rate is 12-25%.

Because of a high risk of recurrence, radiation therapy is recommended for patients who have positive histologic findings in the neck and multiple node metastasis or extracapsular spread.

Generally, the following characteristics of nodal metastasis affect prognosis in the supraomohyoid neck dissection:

  • Extracapsular spread: This condition adversely affects the prognosis. The pathologist looks systematically for extracapsular spread, which is commonly encountered. Tumor spread beyond the capsule of an LN is the most important prognostic factor related to recurrence in the neck.

  • Sites of nodal involvement: The prognosis and survival rates are poor when multiple levels of neck nodes are involved. If the contralateral side is involved, prognosis is poor.

  • Number of nodes: A greater number of involved LNs portends a poorer prognosis. Additionally, risk of recurrence and poor survival rate increases.

  • Node fixation: In general, fixation occurs with large masses, and prognosis is poor. Supraomohyoid neck dissection is not indicated in fixed masses.

  • Degree of differentiation: The risk of cervical metastasis correlates with the grade of tumor differentiation at the primary site. Poorly differentiated tumors are more aggressive and carry a poor prognosis.

  • Involvement of the surgical margin: A positive surgical margin at the primary tumor site carries a poor prognosis.

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Future and Controversies

Once the neck has metastatic disease, adequate treatment is essential. Preoperatively, no method can be used to identify all metastatic disease clearly. Therefore, false-positive and false-negative results are common. The pathologist's examination of LNs removed during surgery is the optimum standard for detection of occult metastasis.

Accordingly, the decision to treat the neck electively depends on the risk of occult metastatic disease associated with a particular primary tumor. Treat patients who have a 20% or higher possibility of harboring metastasis.

Elective management of the neck can be accomplished with surgery or radiation therapy. Surgery is probably selected when the primary tumor is treated with surgery and postoperative radiation therapy is not planned. Furthermore, pathology results define the actual status of neck nodes and serve to guide further treatment. Management is not standardized and varies according to institution, geographical area, and surgeon.

Selection of treatment modality is a controversial subject because the decision to preserve a particular group of nodes remains intraoperative and is based on the surgeon's or pathologist's findings. Although general opinion holds that selective neck dissection is a good alternative for the N0 neck, other alternatives are available (eg, elective treatment, waiting and observing, surgery, radiation).

Because indications are not standardized, the question of comprehensive neck dissection versus selective neck dissection depends on the surgeon. This lack of standardization places the onus of deciding whether to remove levels I-V or to remove a particular group of nodes on the surgeon.

In the future, surgeons worldwide must accomplish the following:

  • Develop better techniques for evaluation of neck metastasis.

  • Define and standardize indications for preoperative and postoperative radiation therapy of the neck.

  • Define and standardize clinical criteria for selective and comprehensive neck dissection.

  • Define and standardize indications for the N0 neck.

  • Define and standardize indications for the N0 neck after using chemotherapy/radiation for the primary tumor.

  • Define and standardize indications for the N+ neck.

  • Define and standardize the role of PET/CT in the assessment and identification of neck metastasis.

  • Further investigate and analyze prognostic indicators.

  • Continue clinical research in these areas.

Special acknowledgment

The authors wish to acknowledge Joan Flaherty, RN, for her editorial assistance and Gustavo Díaz, MD, for taking the digital surgical photos.

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