Infection and Serohematoma

Infection following functional and selective neck dissection is unusual, around 3%, and frequently related to hematoma. Infection is more frequent when the neck dissection is associated with surgical procedures that include opening of the aerodigestive tract. The majority of wound infections are related to pharyngocutaneous fistula after laryngectomy. Infection is best prevented by meticulous sterile surgical technique, gentle handling of the tissue, irrigation, and adequate placing of suction catheters. Necrotic tissue, in the form of residue after either ligature or coagulation, is a focus for bacterial growth. Suction catheter minimizes the incidence of hematoma and seroma, which are frequently associated with wound infection by constituting an ideal media for bacterial growth.

Hematoma and seroma are usually due to inadequate hemostasis at the time of surgery, coagulation disorders, drain obstruction, or incorrect placement of drains. Any effective measure that prevents dead space and hematoma is also useful in minimizing infection. We usually place one suction catheter on each side of the neck after neck dissection. Correct functioning of the drain should be checked immediately after surgery and periodically during the early postoperative period. Inadequate suture of the trachea to the skin in patients requiring tracheostomy results in a cervical opening that prevents vacuum, leading to blood collection and eventually infection, when suction drains are used. The drain is removed on the second or third postoperative day, depending on the output. If seroma develops in spite of these maneuvers, it can be evacuated by needle aspiration, drained through the wound, or observed for gradual absorption. However, prompt drainage will decrease the chances of bacterial contamination.

In procedures not requiring opening of the aerodigestive tract, functional neck dissection is considered a clean surgical procedure, and perioperative antibiotics are not beneficial in preventing infection. Antibiotic prophylaxis is important to decrease the infection rate in some surgical procedures, although it is not the key to the problem in isolated neck dissection. Different antibiotic combinations that cover aerobic and anaerobic bacteria are reported depending on the individual preferences. Dose, time of administration, and type of antibiotic depend on personal preferences and are different at each institution.

Infection should be suspected in a patient with spiking fever, chills, malaise, odor, and swelling or edema of the skin flaps. A small separate incision, or the opening of a limited window in the skin incision, is usually sufficient to drain a serohematoma and prevent further elevation of the flaps with the risk of necrosis and exposure of the great vessels.

Wound Dehiscence

Wound dehiscence is related to inadequate planning of the incision or to infection. Proper placement of the incision should be planned before surgery. The location of the incision and its length should be sufficient to allow adequate exposure to minimize the need for vigorous wound retraction intraoperatively. The skin flaps should be carefully protected from retractors or cautery. We usually fix wet towels to the skin flaps to protect the skin throughout the operation and to avoid direct traction over the skin edge. Crosshatch marks should be avoided to improve the cosmetic results and to avoid additional scarring. Methylene blue or surgical pen marks allow proper realignment of long incisions during skin closure without the risk of additional scars.

In previously irradiated patients, careful skin realignment and subcutaneous suture are important to avoid wound dehiscence facilitated by radiation-induced devascularization. When the patient has been heavily irradiated and the skin is atrophic, it is better to use mattress sutures, placing a rubber catheter between the suture and the skin to decrease tension with subsequent ischemia and skin necrosis.

Chylous Fistula

Chylous leakage is an uncommon complication, with a reported incidence of 1 to 2.5%. It is much more frequent on the left side of the neck. When the thoracic duct is to be ligated during surgery, it should be surrounded by muscle, fascia, or adipose tissue to avoid sectioning its thin wall with the ligature. After ligation, the lower part of the left side of the neck must be carefully inspected for chyle pooling. Asking the anesthesiologist to increase the intrathoracic pressure and placing the patient in the Trendelenburg position are helpful in the intraoperative identification of chyle leak in the area of the thoracic duct. It is important to note that in most patients developing postoperative chyle fistula, this was previously identified and apparently controlled intraoperatively.

In the postoperative period, chylous fistula is recognized by the appearance of a milky fluid in the drains. This is usually evident within the first 5 days after surgery. The chylous origin of the fluid can be confirmed by measuring the content of triglycerides, usually over 100 mg/dL. When chylous leak is suspected, dietary modifications can be prescribed. Low fat diet, either enteral or parenteral, is usually recommended because medium-chain triglycerides are absorbed directly into the portal venous circulation, avoiding the thoracic duct. Elevation of the head, repeated aspiration, and pressure dressing are also recommended. It is important to note, however, that preservation of the sternocleidomastoid muscle in functional and selective neck dissection constitutes an important obstacle for successful compression. The daily volume of the leak has been reported to range from 80 to 4,500 mL. When more than 500 mL of chyle drain per day, nonsurgical stop is unlikely.

If no response is found upon conservative treatment, the lower part of the neck should be surgically explored. Before surgery is attempted it may be helpful to put the patient on a high lipid enteral diet to give chyle a thick and milky consistency, which will improve the intraoperative identification of the leak.

Bleeding

Bleeding is not a frequent complication after neck dissection, but when it happens, it is important to determine whether the hemorrhage is due to a small superficial vessel or to a more important deep vessel. Superficial bleeding is usually bright red, it does not bulge the skin flaps, and it tends to stop with gentle external compression or by placing a stitch around the bleeding point. Generalized oozing of blood can produce up to 500 mL in a few hours. On the other hand, ballooning of the skin flaps or filling the drain system containers with more than 250 mL of blood in less than 30 minutes indicates a more serious hemorrhage.

In our experience, the most frequent sources of venous bleeding after functional and selective neck dissection are the retromandibular vein at the tail of the parotid gland, the branches of the transverse cervical vein in the supraclavicular fossa, and small veins draining into the internal jugular vein. When the tail of the parotid gland is included in the resection, the retromandibular vein should be identified and ligated. Dissection of area IV and the lower part of area V may result in inadvertent sectioning of small branches of the transverse cervical vein. When the patient’s blood pressure is low, the inferior stump of the transected vein may retract caudally without bleeding during the operation. Then, when the patient wakes up from the anesthesia, cough and increased abdominal pressure may induce bleeding. The same may happen when small branches of the internal jugular vein are sectioned during the dissection of the carotid sheath, especially those located on the posterior aspect of the vein.

To identify any possible source of venous bleeding not detected during the operation, it is important to wash the surgical field with saline at the end of the operation and ask the anesthetist to increase the venous pressure to force bleeding from unnoticed opened veins. When hemoclips are used during the operation, care must be taken while cleaning to avoid unintentional displacement of the clips, leaving a collapsed vessel that can eventually bleed with a sudden increase in venous pressure. On the other hand, the small veins draining directly into the internal jugular vein are better ligated than cauterized, especially when they are to be sectioned close to the wall of the internal jugular vein because necrosis induced by the cautery may produce hemorrhage in the late postoperative period. Special attention should be paid to electrocautery in previously irradiated patients.

Arterial bleeding is more evident at surgery than venous bleeding. It is usually secondary to malposition or displacement of a ligature. The most frequent sources of arterial bleeding in our experience are the superior laryngeal pedicle and the inferior thyroid artery.

When hemorrhage is suspected in the immediate postoperative period, adequate blood replacement and airway maintenance should be ensured as first priority. Then, the patient should be taken to the operating room where the neck should be explored under aseptic conditions with good illumination and adequate material. Evacuation of blood clots and hematoma, along with washing the surgical field, helps in identifying the bleeding vessels and reduces the risk of infection. The use of compressive dressing is not recommended because, although it may reduce postoperative edema, it does not stop the development of hematoma, and may in fact delay its recognition.