Branchial cleft anomalies are the most common congenital lateral neck pathologies in children. These lesions can occur as a sinus, a fistula or a cyst. First branchial cleft anomalies comprise 5 to 25% of all branchial anomalies, and are a duplication of the external ear canal. They are divided into 2 types, according to the location and the histology.
Second branchial anomalies are the most common, comprising 40 to 95% of all branchial anomalies. They usually present as a painless neck mass, an acute enlargement following upper respiratory tract infection or as a draining pit.
Pyriform fossa anomalies (formerly third and fourth branchial cleft anomalies) are relatively rare. Third branchial cleft sinus usually presents as recurrent thyroid infection or abscess. Fourth branchial cleft anomaly can present either asneonatal neck mass or as recurrent deep neck infection or suppurative thyroiditis. While the treatment of fourth branchial cleft anomaly is endoscopic cauterization, thedefinitive treatment of first, second, and third branchial cleft anomalies is surgical excision.
14 Branchial Cleft Anomalies, Sinuses, and Cysts
Branchial cleft anomalies are the most common congenital lateral neck pathologies in children. These lesions can occur as a sinus (connecting the skin or the pharynx to a blind pouch in the neck), a fistula (an open tract connecting the skin to the pharynx), or a cyst (if there is no connection to the skin or to the pharynx).
The branchial arches appear from the fourth to the seventh gestational weeks. They are located on the supero-lateral aspect of the fetus, and are composed of mesoderm. The arches are separated by external clefts and internal pouches. Each arch develops into a nerve, a blood vessel, and a muscle bundle. Incomplete obliteration of the clefts or grooves between the arches causes a variety of anomalies.
This chapter will focus on the surgical resection of these anomalies. Complete explanation of the normal and pathological developmental process of these structures is beyond the scope of this chapter and hence will not be discussed.
14.2 First Branchial Cleft Anomalies
Type I first branchial cleft anomalies are less common and considered to be a duplication of the membranous external auditory canal (EAC). It courses parallel to the EAC, supero-lateral to the facial nerve, and terminates either in the cartilaginous–bony junction or in the middle ear cavity, attached to the umbo or to the malleus (▶ Fig. 14.1a). Once infected, they drain either to the pre-auricular region, in the post-auricular region, or inferior to the lobule. 4
Type II cysts are more common. They are considered to be duplications of both the cartilaginous and bony EAC. The tract is located lateral or medial to the facial nerve (▶ Fig. 14.1b). Once infected, it presents as otorrhea in the EAC or as a draining pit in the angle of the mandible. Of note, type II cysts may present as cysts in the parotid gland, mimicking a primary parotid mass. 4
Work type I lesions characteristically occur in young children, presenting as a cystic lesion obstructing the external auditory canal, as a draining pit in the external ear canal or as recurrent infections.
Work type II lesions characteristically occur in older children. They present similarly to type I but can also present as a draining pit in the neck, near the angle of the mandible.
Acute infection should be treated with antibiotics that cover S. Aureus, methicillin-resistant S. aureus, and upper respiratory tract anaerobes, and incision and drainage may be necessary if an abscess is formed. Surgical removal is indicated shortly after the resolution of the acute infection.
14.2.1 Preoperative Evaluation and Anesthesia
A CT scan with contrast should be performed prior to the surgery. MRI typically demonstrates low T1 signal and high T2 signal, and can be of help in visualizing the parotid gland and its relation to the lesion. The risk of potential facial nerve injury should be discussed with the patient and family.
The anesthesiologist should be informed that the child must not be paralyzed throughout the procedure, in order to enable the surgeon to identify and stimulate the branches of the facial nerve. A nerve integrity monitor should be used.
The neck is extended and the head is rotated to the opposite side.
The face and the upper area of the neck should not be covered with sheets but draped, in order to allow visualization of the mouth angle and the corner of the eye.
14.2.2 Surgical Technique
A pre-auricular incision that extends behind the ear and incorporates the fistulous tract in the neck is created (▶ Fig. 14.2). A flap is raised to expose the parotid gland, and the fistulous tract is identified and dissected free from the surrounding tissue.
The facial nerve stem is identified according to the same landmarks used in adults (▶ Fig. 14.3).
In young children, the nerve is located further laterally, and because the mastoid tip is not fully developed, the nerve can appear more superficial than might be expected.
Dissection along the fistulous area should be continued. It may lead to a cartilaginous tube containing dermal elements, which should all be resected.
The fistula usually passes medial to the facial nerve stem and its branches, ending either directly in the external ear canal or in a cartilaginous structure adjacent to the ear canal. This structure should be dissected and excised. Of note, the dissection may leave a defect in the external ear canal which can either be closed primarily or left for secondary healing.
The dissection continues deep to the facial nerve (▶ Fig. 14.4). Small branches of the superficial temporal artery should be identified and ligated.
A passive or an active drain is placed in the surgical field, according to the amount of dissection performed. The skin flaps are sutured using 4–0 Vicryl for the subcutaneous tissue and a 5–0 Monocryl for the skin.
A pressure dressing is applied to the wound for 24 hours.
Of note, simple excision of the lesion without facial nerve identification may be suitable for excision of uninfected type I lesions. A nerve integrity monitor should be used in these cases.
14.2.3 Postoperative Treatment
Antibiotics are not routinely administered. If an active infection is identified during the surgery, antibiotics are administered postoperatively. The drain is left in place for 1 to 3 days, depending on the amount of drainage. The child is observed overnight because possible postoperative complications include facial or cervical hematoma. 1