Laura H. Swibel Rosenthal, MD
When the back of the nose is not open or not communicating with the rest of the airway this is called choanal atresia. It is a congenital condition (meaning a person is born with it) that occurs in about 1 in 6000 to 8000 live births. The exact reason for the anomaly is unknown and probably multifactorial (from many causes), or a mix of genetic and environmental causes. It has been reported in association with maternal use of methimazole. When the nasal airway develops, it starts at the level of the skin of the face, where two indentations or nasal sacs are formed. At the inferior aspect is the primitive palate. An oronasal membrane develops behind the palate between the nose and the oral cavity. As the nasal pits become deeper and deeper, they eventually connect with the oral airway (behind the palate). If this canalization (tunneling) is incomplete, the result is choanal atresia. Figure 1 shows the endoscopic view (using a small telescope to look through the nose) of the choana, with the floor of the nose (or palate) below and the adenoid bed (a region of lymphoid tonsil-like tissue at the very back of the nose) behind. Figure 2 shows a similar vantage point in a patient with choanal stenosis (or a small choana). It occurs on only one side about twice as often as on both sides. About 1/3 are bilateral (two-sided) and 2/3 are unilateral (one-sided).
Figure 1: Endoscopic view of the back of the normal nose. The opening is called the choana. The space behind the nose is the nasopharynx. Adenoids (A), lumpy pink tissue similar to tonils, can normally be seen in the nasopharynx. In choanal atresia, this area is completely closed. All that can be seen is tissue similar in appearance to the floor of the nose (F).
SIGNS AND SYMPTOMS OF UNILATERAL CHOANAL ATRESIA
When unilateral, the right side is affected more often than the left. If the atresia (narrowing or complete blockage) is only on one side, sometimes it is identified at birth but it can go unnoticed for a few years. Most commonly, children will have chronic thick drainage from one side of the nose.
SIGNS AND SYMPTOMS OF BILATERAL CHOANAL ATRESIA
If the atresia is present on both sides, it is much more likely that the newborn infant will have symptoms with significant difficulty breathing and feeding. Patients may have noisy breathing, turn blue while sleeping or feeding, and aspirate milk. When the patient awakens, coughs or cries the mouth will open again, allowing air to move through to the lungs, and symptoms will often temporarily resolve. Feeding slowly can allow the baby to breathe between swallows. However, a feeding tube is often placed from the oral cavity into the stomach to make sure that the patient safely receives adequate feeds.
INITIAL TREATMENT OF BILATERAL CHOANAL ATRESIA
Bilateral choanal atresia can be a life-threatening situation. In an emergency, an oral airway or short tube along the top of the tongue can be placed so that the airway stays open. Patients will often require an intubation (a breathing tube from the mouth to the airway below) or tracheostomy (a tube bringing air directly from an opening made in the neck down to the airway below). One of the first signs in the delivery room or neonatal intensive care unit (NICU) that a patient may have a bilateral choanal atresia is the inability to pass a small catheter (tube) down either side of the nose into the stomach. Similarly, a small flexible endoscope may also be passed into the nose at the patient’s bedside to examine the inside of the nose and confirm the anatomy. Once an airway is established and the patient is stable, a CT scan (computed tomography) and possibly an MRI (magnetic resonance imaging) may be obtained to confirm the choanal atresia or identify other reasons for the patient’s symptoms.
SURGERY TO REPAIR OR OPEN THE CHOANA
The choanal atresia can be repaired or opened with a surgical procedure. 70 to 90% of choanal atresia involves bone and the soft tissue covering the bone. Only in a small portion of cases is the narrowing composed of only soft tissue and no bone. There are multiple techniques that can be used during surgery, but most often an endoscopic approach is used (using a small telescope and instruments through the nose). With an endoscopic approach there are no incisions on the face or the palate (the roof of the mouth). The procedure is done through the nostrils. The bone and soft tissue that is blocking the opening is taken down until it is open to the area where it connects with the pharynx (the throat behind). This area is called the nasopharynx. (It is above the oropharynx, the area behind the oral cavity. These spaces connect with one another.) An “open” approach can be used in which an incision is made into the palate from the oral cavity to access the narrowing in the nose. After the atresia is opened, the palate is then closed. In either case, endoscopic or open, a temporary stent may or may not be placed to keep the newly created choana open. It is possible that the opening may begin to close, with or without a stent. More than one surgery is often necessary to try to keep the nasal airway open. (See Figures 2 and 3) A medication called mitomycin may be used during surgery to reduce postoperative scarring. However, a suitable airway is attainable in the vast majority of patients.
Figure 2: This is a similar view as in Figure 1. This endoscopic view shows a stenosis or narrowing of the choana. In a complete obstruction, there would be no hole, as there is above. The stenosis in this patient is present about one or two years after a single attempt at repair in infancy.
Figure 3: The choana is shown immediately after opening during endoscopic surgery. The nose heals quickly. There may be mild to moderate pain for a few days. Saline spray is used at home to help rinse the nose and keep it clean.
Once the atresia is repaired and well-healed, patients who required a tracheotomy can usually have the tracheotomy removed as long as there are no other problems for which the tracheotomy would be necessary. The timing of removal of the tracheotomy will vary by patient.
CHOANAL ATRESIA ASSOCIATED WITH OTHER CONGENITAL ANOMALIES
Choanal atresia usually occurs in the absence of any other anomalies (problems with other parts of the body) or syndromes. However, there are syndromes associated with choanal atresia for which every patient should be evaluated. This is especially true for those with bilateral (both sides) choanal atresia, as other congenital anomalies are more common in those affected bilaterally. The most common syndrome associated with choanal atresia is CHARGE syndrome. Patients with this may have other findings such as coloboma (a slit in the eyelid or iris), heart problems, retardation of growth or development, genital or urinary problems, and ear problems (malformation and/or hearing loss). About 60% of patients with CHARGE syndrome have bilateral choanal atresia. This particular syndrome is genetic, inherited in a dominant pattern. One of the patient’s parents is usually affected, although the parent can be more or less affected, meaning that the symptoms or features may be more or less noticeable. Genetic mutations can also be sporadic (not inherited, but spontaneous) and they can be mosaic (affecting some of the patient’s cells and not others). In this case, neither of the patient’s parents would have the mutation or be affected. Mutations in the CHD7 gene should be tested and are identified in 75% of patients with CHARGE. The remaining 25% of patients may have a mutation in another gene or no genetic mutation. Microdeletion of 5q11.2 has also been associated with choanal atresia.
©American Rhinologic Society