Choanal Atresia

Updated: Oct 04, 2017
  • Author: Ted L Tewfik, MD; Chief Editor: Arlen D Meyers, MD, MBA  more...
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Overview

Practice Essentials

Complete nasal obstruction in a newborn may cause death from asphyxia. During attempted inspiration, the tongue is pulled to the palate, and obstruction of the oral airway results. Vigorous respiratory efforts produce marked chest retraction. Increased cyanosis and death may occur if appropriate treatments are not available; however, if the infant cries and takes a breath through the mouth, the airway obstruction is momentarily relieved. Then the crying stops, the mouth closes, and the cycle of obstruction is repeated.

Choanal atresia is depicted in the image below.

Choanal atresia. Rhinogram demonstrating blockage Choanal atresia. Rhinogram demonstrating blockage of radiopaque dye at the posterior choanae. From T.L. Tewfik and V.M. Der Kaloustian, with permission.

Workup

Computed tomography (CT) scanning is the radiographic procedure of choice in the evaluation of choanal atresia. For good results, careful suctioning is performed to clear excess mucus, and a topical decongestant is applied.

Management

Treatment can be divided into emergent and elective definitive categories. Bilateral choanal atresia in a neonate is an emergency that is best initially treated by inserting an oral airway to break the seal formed by the tongue against the palate. This oral airway can be well tolerated for several weeks.

Surgical procedures

Transpalatal repair is a technique that provides excellent exposure and has a high success rate but requires more operative time. The increased blood loss and the possible occurrence of palatal fistula, palatal dysfunction, and maxillofacial growth disturbance are complications of this procedure.

The endoscopic technique (nasal or retropalatal), with or without powered instrumentation, offers excellent visualization with great ease in removing the bony choanae. [1] Combined transoral-transnasal is another technique that provides a good alternative for managing choanal atresia, with easier, 4-handed surgery to ensure adequate posterior choana for nasal breathing. [2]

Microdebriders continue to advance the field of endoscopic surgery, providing clearer operative fields and causing less tissue trauma for experienced surgeons.

Procedures using carbon dioxide and potassium titanyl phosphate (KTP) lasers are easy and quick and create minimal discomfort for the patient. The time of hospitalization is short, and the operation can be repeated if a good result is not initially achieved. Most importantly, a stent is not usually needed.

Postoperative details

The use of stents in the treatment of patients with choanal atresia is a controversial subject. Some surgeons believe that stents are useful in stabilizing the nasal airway in the postoperative period to prevent the development of stenosis by maintaining a lumen. However, others believe that stents may act as a nidus for infection and may induce a foreign body reaction; this may contribute to choanal restenosis. Therefore, the use of stents following repair of choanal atresia requires the use of prophylactic antibiotic and antireflux medications.

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History of the Procedure

In 1755, Roederer first described congenital choanal atresia; therefore, this condition has been recognized for more than 200 years. In 1854, Emmert reported the first successful surgical procedure for congenital choanal atresia in a 7-year-old boy using a curved trocar transnasally. Over the years, the necessity of serial dilatations to maintain patency of the choanae has been clearly recognized.

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Epidemiology

Frequency

The average rate of choanal atresia is 0.82 cases per 10,000 individuals. Unilateral atresia occurs more frequently on the right side. The ratio of unilateral to bilateral cases is 2:1. A slightly increased risk exists in twins. Maternal age or parity does not increase the frequency of occurrence. Chromosomal anomalies are found in 6% of infants with choanal atresia. Five percent of patients have monogenic syndromes or conditions.

Race

Choanal atresia occurs with equal frequency in people of all races.

Sex

Studies report significantly more females than males affected by choanal atresia. A report by Michalski et al, using data from the National Birth Defects Prevention Study (1997-2009), indicated that the female-to-male ratio for infants with choanal atresia is 2.2. [3]

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Etiology

The nasal cavities extend posteriorly during development under the influence of the posteriorly directed fusion of the palatal processes. Thinning of the membrane occurs, which separates the nasal cavities from the oral cavity. By the 38th day of development, the 2-layer membrane consisting of nasal and oral epithelia ruptures and forms the choanae (posterior nares). Failure of this rupture results in choanal atresia. Although these choanae are not in the same location as the definitive choanae, which are eventually located more posteriorly, the unexpectedly anterior extent of choanal atresia is explained. [4]

In 2008, Barbero et al suggested that prenatal use of antithyroid (methimazole, carbimazole) medications was linked to choanal atresia. [5]

Lee et al (2012) evaluated the association between continuous and categorical infant T4 levels and nonsyndromic choanal atresia. [6] They suggest a role of low thyroid hormone levels in the development of choanal atresia, or that low newborn T4 levels are potential proxy measures of a risk factor present during the critical period of development.

Using data published data from the National Birth Defects Prevention Study, Kancherla et al (2014) found evidence linking choanal atresia to maternal exposure to various nutrients, thyroid medications, and cigarettes. The investigators looked at prepregnancy exposures (within 1 year prior to conception) and periconceptual exposure (between 1 month before and 3 months after conception) in 117 women who gave birth to infants with choanal atresia and 8350 control mothers. Positive associations were found between the following prepregnancy exposures and choanal atresia [7] :

  • Intake in the highest quartile: Vitamin B-12, zinc, niacin

  • Intake in the lowest quartile: Methionine, vitamin D

  • Coffee (≥ 3 cups per day)

Positive associations were also found between the following periconceptual exposures and choanal atresia:

  • Thyroid medications

  • Cigarette smoking

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Pathophysiology

A number of theories have been proposed to explain the occurrence of choanal atresia, and they can be summarized as follows:

  • Persistence of the buccopharyngeal membrane

  • Failure of the bucconasal membrane of Hochstetter to rupture

  • Medial outgrowth of vertical and horizontal processes of the palatine bone

  • Abnormal mesodermal adhesions forming in the choanal area

  • Misdirection of mesodermal flow due to local factors

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Presentation

The clinical evaluation includes a complete physical examination to assess for other congenital anomalies. A small feeding tube could be used to determine the patency of the choana, but a complete nasal and nasopharyngeal examination should be performed using a flexible fiberoptic endoscope to assess the deformity. A simple method using the automatic tympanometer to screen newborns for congenital choanal atresia was recently published. The sensitivity and specificity of the technique in diagnosing a patent nostril was reported as 100%. However, a high level of suspicion is required to diagnose bilateral choanal atresia.

Symptoms of severe airway obstruction and cyclical cyanosis are the classic signs of neonatal bilateral atresia. When crying alleviates respiratory distress in an obligate nasal breather, the neonatologist should be alerted to the probability of bilateral choanal atresia. Unilateral atresia may not be detected for years, and patients may present with unilateral rhinorrhea or congestion.

Many patients have an associated narrowed nasopharynx, widened vomer, medialized lateral nasal wall, and/or arched hard palate. Associated malformations occur in 47% of infants without chromosome anomalies. Nonrandom association of malformations can be demonstrated using the CHARGE association, which appears to be overused in clinical practice. The components of the CHARGE association are as follows:

  • Coloboma of the iris, choroid, and/or microphthalmia

  • Heart defect such as atrial septal defect (ASD) and/or conotruncal lesion

  • Atresia of choanae

  • Retarded growth and development

  • Genitourinary abnormalities such as cryptorchidism, microphallus, and/or hydronephrosis

  • Ear defects with associated deafness (The external, middle, and/or inner ear may be involved. Only a small proportion of infants with choanal atresia and related components probably represent this entity.)

The percentages of the different anomalies in CHARGE association are as follows:

  • Coloboma - 80%

  • Heart defect - 58%

  • Atresia of choanae - 100%

  • Mental retardation - 94%

  • Growth deficiency - 87%

  • Genital hypoplasia in males - 75%

  • Ear anomalies - 88%

Differential diagnosis

Deviated nasal septum

Dislocated nasal septum

Septal hematoma

Mucosal swelling

Turbinate hypertrophy

Encephalocele

Nasal dermoid

Hamartoma

Chordoma

Teratoma

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