CHOANAL ATRESIA
SOURCE: Dept. of Otolaryngology, UTMB, Grand Rounds
DATE: March 6, 1991
RESIDENT PHYSICIAN: R. Paul Fulmer, M.D.
FACULTY: Karen H. Calhoun, M.D.
SERIES EDITOR: Francis B. Quinn, Jr., M.D.

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I. General

II. Embryology

• A. Four theories for the development of choanal atresia:
  • 1. Persistence of a buccopharyngeal membrane from the foregut.
  • 2. Persistence of the nasobuccal membrane of Hochstetter - most commonly accepted theory.
  • 3. The abnormal persistence or location of mesodermal adhesions in the choanal region.
  • 4. A misdirection of mesodermal flow secondary to local genetic factors better explains the popular theory of persistent nasobuccal membrane.

• B. Normal Nasal Development and an explanation of the mesodermal flow theory: Normal nasal development begins with the migration of the neural crests cells from their origin in the dorsal neural folds, laterally around the eye and transversing the frontal process. This begins about the 4th week and the nasal architecture is completed by the 12th week. During the 9th week, the neural crest cells migrate through a meshwork of hyaluronic acid and collagen filaments to a preordained position within the facial processes. Various genetic factors affect this migration. If the flow of these cells is altered in their position or in their total numbers, then the burrowing of the nasal pits may not occur as planned and in turn the thinning and eventual rupture of the anterior primary choana is altered. After this migration of neural crest cells, the primitive mouth and nose begin to separate in a posterior direction with the nasoseptal elements growing caudally while the lateral palatal processes are growing medially and the tongue drops to the floor of the mouth. This creates the boundaries of the atresia plate:
  • 1. superiorly - the undersurface of the body of the sphenoid bones,
  • 2. laterally - the medial pterygoid lamina,
  • 3. medially - the vomer,
  • 4. inferiorly - the horizontal portion of the palatal bone. This growth of the palatal process and septum posteriorly can cause the backward migration of a collection of mesoderm left by the original flow defect. However the vomer's posterior growth stops at the posterior margin of the septum, but the lateral portion of the mesenchymal mass can continue to migrate. This causes the atresia plate to lie in a tangential plane in the choana at birth. If a lesser amount migration occurs posteriorly then a thin membranous plate is more likely seen. However, if the migration is excessive then a plate of bone from 1 to 12 mm thick can been seen. With this degree of plate formation, a funnel-shaped nasal passage is created with the marked fullness in the lateral and superior wall region. Therefore, this better explains the theory of a persistent nasobuccal membrane causing the choanal atresia. Also due to the general developmental abnormality of the nose with this anomaly, additional changes are also seen:

  • 1. an accentuated arch of the hard palate,
  • 2. a sweeping inward of the lateral and posterior nasal walls,
  • 3. a narrowing of the nasopharynx by the posterior and lateral pharyngeal walls.

III. Clinical Presentation

• A. Bilateral choanal atresia
  • 1. Causes complete nasal obstruction - immediate respiratory distress and even potential death due to asphyxia (because newborns are obligate nose breathers until approximately 4 to 6 weeks at which time mouth breathing is learned).
  • 2. The respiratory obstruction is cyclic - as the child falls asleep the mouth closes and a progressive obstruction starting with stridor followed by increased respiratory effort and cyanosis. Either the observer opens the child's mouth or the child cries and the obstruction is cleared.
  • 3. Initial feeding is often the alerting event - as the child starts with inability to eat and breath at the same time, there is a progressive obstruction of the airway and subsequent cyanosis and choking due to aspiration of the milk. This can mimic a tracheoesophageal fistula.

• B. Unilateral choanal atresia
  • 1. Rarely causes any acute respiratory distress.
  • 2. Most common finding is a unilateral mucoid discharge.
  • 3. Unilateral choanal atresia does not require any immediate surgical attention.

• C. Associated congenital anomalies
  • 1. CHARGE association - (C,coloboma; H, congenital heart disease; A, atresia choanae; R, retarded growth and development; G, genital anomalies in males; E, ear anomalies and deafness).
    • a. 59% of patients with CHARGE Association have bilateral choanal atresia. The rest have unilateral choanal atresia.
    • b. therefore, when bilateral choanal atresia is diagnosed a complete physical assessment by a pediatrician should be performed.
  • 2. 75% of all patients found to have multiple congenital anomalies and who have choanal atresia, have bilateral choanal atresia.

IV. Evaluation and Planning

• A. Physical Exam - Once the diagnosis of choanal atresia has been made it can be confirmed initially on physical exam by:
  • 1. failure to pass a # 6 to 8 French plastic catheter through the nares into the pharynx. (a typical solid feeling will be encountered at the level of the posterior choana approx. 3-3.5 cm from the alar rim).
    • a. if however an obstruction is encountered at approx. 1-2 cm from the alar rim, then this is most likely due to a traumatic deflection of the nasal septum during delivery.
    • b. if the nasal obstruction is due to mucosal swelling and turbinate hypertrophy, then a catheter will pass into the pharynx and the obstruction is just functional.
  • 2. Passage of soft metal probes have been advocated for the same reasons as above.
  • 3. Placing wisps of cotton in front of the nares and watching for the presence or absence of nasal movement of air.
  • 4. Placing methylene blue in the nares and not visualizing it within the pharynx.

• B. Imaging Studies
  • 1. Plain films and tomograms of the skull with radiopaque dye instilled into the nasal cavities.
  • 2. An axial noncontrast high resolution CT scan with thin sections (2-5mm) has become the single radiographic study of choice. The CT scan has proven invaluable in the accurate assessment of both the normal and abnormal anatomy of the nasal cavity, posterior nasal choanae and nasopharynx. The knowledge obtained from the CT scan is valuable in the preoperative planning of the method and design of the repair.
    • a. Slovis, et al. reviewed multiple CT scans of both normal patients and patients with choanal atresia and found two parameters which are useful in evaluating the abnormal anatomy of choanal atresia.
      • i. choanal airspace measurement (normal) - the distance from the lateral wall of the nasal cavity to the vomer bone. The mean choanal airspace distance in the newborn was found to be 0.67 cm and it increased 0.027 cm / year until age 20y.o.
      • ii. vomer bone width (normal) - the mean width was found to be 0.23 cm in children 0-8 y.o. and only increased to 0.28 cm between 8 and 20 y.o.
      • iii.choanal airspace measurement (atresia) - this measurement was absent for patients with bony atresia and was one third of normal for patients with membranous atresia.
      • iv. vomer bone width (atresia) - were found to be almost three times the normal group for patients with bony atresia with a mean width of 0.6cm. The width was found to be only 0.3 cm for those with membranous atresia.
      • v. The CT scan is also very useful for repeated consultation during the procedure allowing the surgeon to determine where and how much of the posterior hard palate need be removed to expose the atresia plates.
      • vi. Likewise during the revision procedures, the CT scan can accurately determine any residual posterior choanal stenosis and the extent of scar tissue.
      • vii. CT scan also helps exclude most if not all of the other diseases which could cause nasal obstruction of the newborn:
        • a. generalized mucosal congestion of the newborn ("stuffy nose syndrome")
        • b. encephalocele,
        • c.tumors including dermoids, gliomas, hamartomas, chordomas, teratomas, and rhabdomyoscarcomas to name a few, iv. traumatic birth deformity or dislocation of the nasal septum causing either partial or complete nasal obstruction. This is the most common cause of partial or complete nasal obstruction in the newborn!

V. Initial Management

• A. Airway - an oral airway of some sort must be implemented very early on in the treatment of newborns with choanal atresia.
  • 1. a typical anesthesia oral airway is often sufficient, however if not then,
  • 2. Orogastric tube - Hough pointed out that the obstructive seal between the tongue and the palate in infants with bilateral choanal atresia can be broken with the insertion of a large orogastric tube(No. 12 or 14 French). Once the seal is broken then it serves as an oral airway as well as a conduit for feeding. This is used with only moderate success.
  • 3. Intraoral nipple - a large nipple can be modified by having its end cut off and then ties are attached to the nipple and placed around the occiput. This type of airway is called a McGovern nipple and provides an airway through which the baby can breath. A very small feeding tube can then we passed either through another hole in the nipple or along side the nipple for gavage feeding. This is the preferred method of establishing an oral airway.
  • 4. Tracheostomy - this is a controversial issue and many physicians conclude that there is never a need for this drastic a step in the initial management of infants with choanal atresia. However, Finkelhor et al. recently reported a retrospective review of sixteen patients who had CHARGE Association and they concluded these patients have a high propensity of airway instability. They also reported that these children's early repair of their choanal atresia is rarely successful, primarily due to their abnormal anatomy of their nasopharynx and upper aerodigestive tract. They also found that these patients tended to have at least one cardiopulmonary arrest prior to their definitive procedure. Therefore, they have proposed that children who have CHARGE Association should have early tracheotomy to protect their brain from anoxic injury and delay the repair of their choanal atresia until they are at lease 2 years of age. This is still a very controversial subject.

• B. Feeding - usually gavage feeding is required until the child has learned to mouth breath. Then once the child learns the mouth breath, then he will swallow air and need frequent 'breathing/burping breaks'.

VI. Surgical Management

• A. Transnasal blind puncture - this is the first technique which was described by Emmert in 1853. This technique should be avoided because of the potently serious complications: CSF leaks, midbrain trauma, and Gradenigo syndrome.
• B. Transnasal Approach (and with Endoscopes)
  • 1. Technique:
    • a. patient is placed under GETA
    • b. self-retaining aural speculum is used to expose the nasal cavity and the atresia plate,
    • c. decongest the nose(ie. neo-synephrine nose drops)
    • d. 0.5% lidocaine with 1:200,000 epi. is injected into the mucosa overlying the bony atresia. (d.1). Benjamin and others have advocated placing the Dott-Dingman self-retaining cleft palate gag at this time to give excellent access to the pharynx and allows the surgeon to monitor the perforation of the atresia plate with a 120 degree Storz Hopkins telescope or a mirror.
    • e. with the microscope (or 2.5-4.0 mm endoscopes) and otologic instruments a mucosal incision is made and the mucosal flaps are elevated and this exposes the posterior vomer and lateral pterygoid lamina,
    • f. then using a diamond burr on a angled handpiece, the bony atresia plate is perforated at the junction of the plate, hard palate, and vomer (which is the thinnest section of the atresia). When performing the endoscopic procedure described by Stankiewicz, the atresia plate is perforated with a small suction tube and then the drill is used to widen the opening. (f.1). the inferior turbinate can be either outfractured or upfractured as necessary to increase the surgeons visualization.
    • g. the remaining atresia plate is then removed, only preserving the anterior mucosal flaps.
    • h. an attic hook can be passed through the enlarging choana to assess the proximity to the lateral pharyngeal walls.
    • i. CAUTION - around the tors tubarius posteriorly and the sphenopalatine vessels behind the middle turbinate.
    • j. KEY - removing the posterior aspect of the septum is accomplished by placing the burr into the nasopharynx through the choanea and bringing it forward and medially against the vomer. (During the endoscopic procedure described by Stankiewicz he uses the backbiting forceps to remove the vomerine septum).
    • k. newly created choana should be approximately the size of a 16-Fr van Buren sound. These should be placed into each nares simultaneously to check the patency and choanal size.
    • l. then a silastic stent should be placed into each nostril and should rest just inside the nasal ala and should only protrude approx. 5 mm beyond the newly formed choanea. (These are left in place for 6-8 weeks).

  • 2. Advantages:
    • a. This approach is faster, easier, and less problematic.
    • b. Blood loss is minimal.
    • c. Excellent for children of all ages when the atresia is thin and there is no nasal deformities or anomalies.
    • d. Pirsig reviewed more than 100 papers dealing with choanal atresia and different operative approaches and he found that the transnasal approach was successful in up to 80% of the cases. However another review of the literature showed a 50-60% restenosis of patients treated with the transnasal approach.
    • e. Allows for earlier repair in properly selected patients and may avoid restenosis. (as early as 24-48 hrs. from the time of diagnosis).
    • f. The child can breast feed immediately post op.
    • g. If no additional problems then the child can be discharged on the 3rd or 4th post op day.

  • 3. Disadvantages and Complications:
    • a. A main disadvantage of this technique is the limited vision the surgeon has via the nares, especially in the newborn if the endoscopes are not used.
    • b. Also the inability to adequately remove enough of the posterior vomerine septal bone and prevent restenosis.
    • c. Longer stenting time post op.
    • d. The endoscopes are not binocular, so the surgeon's position and anatomy have to be rechecked often.
    • e. Can not be done safely and with good results on patients with multiple nasal and nasopharyngeal anomalies.

  • C. Transpalatal Approach
    • 1. Technique:
      • a. The patient is placed under GETA.
      • b. The Dingman-Denhardt mouth gag with the infant tongue blade should then be placed.
      • c. The palate is injected with 0.5% lidocaine with 1:200,000 epinephrine in the area of the mucosal incision.
      • d. Then a Owens type(U-shaped) mucosal incision is made beginning just behind the maxillary tuberosity on one side and then continued medial to the alveolar ridge up to the canine region and then angled back to the nasopalatine foramen. A likewise incision is made on the opposite side and the mucosal flap is elevated taking care not to damage the greater palatine arteries.
      • e. The mucosa of the nasopharynx and nose is elevated and preserved.
      • f. Then the palatine bones posterior to the greater palatine foramina, the atresia plates and the posterior vomer are carefully drilled away using a diamond burr.
      • g. Two 14 or 16 French catheters are passed simultaneously into each nostril to check the patency of the newly created choanea.
      • h. The preserved mucosa is then used to cover the superior and inferior surfaces of the newly formed choanea and then sutured in place to cover the bone.
      • i. Then stents are placed and left in place for 4-6 weeks.
      • j. Theogaraj et al., recommends leaving the oral airway in place for 1-2 weeks post operatively until the child is able to breath through the prosthesis.

    • 2. Advantages:
      • a. the surgeon has better visualization and preservation of nasal mucosal flaps lining the newly produced choanea.
      • b. these patients tend to require a shorter stenting period post op(4 to 6 weeks).
      • c. also there is a higher overall success rate with the transpalatalapproach.
      • d. Pirsing found that the transpalatal approach was successful in up to 84% of the cases.

    • 3. Disadvantages and Complications:
      • a. the incisions, which are identical to those for a cleft palate repair, may have a banding effect on maxillary growth due to scar formation. (Therefore, most surgeons prefer to wait to use this approach until some teeth are in occlusion - at approx.12-18 months).
      • b. the stunting of palatal growth was documented by Freng to have occurred in 52% of his patients studied with the transpalatal approach. (particularly prevalent in those operated on early in life).
      • c. Very few surgeons feel comfortable performing a transpalatal approach on a newborn and will in turn prefer to place a McGovern nipple until oral breathing is established. Also some surgeons will perform a transnasal surgery as a prophylactic procedure and leave the transpalatal surgery for the definitive procedure.
      • d. Increased risk of intraoperative blood loss.
      • e. Increased post op pain and discomfort.
      • f. Also have a greater risk of developing palatal fistulas post op.

VII. Postoperative Care

• A. Stenting: There are multiple types and methods of stenting, but the basic premise is to place either a hard or soft portex/silastic tube into each nostril and secure them in place for a approximate period of 4-8 weeks, depending upon the author.
  • 1. Theogaraj et al., advocates the use of a double barreled silicone Elastomer tube which has a coiled wire incorporated within its walls to prevent collapse.
    • i. He then glues a Dacron-reinforced strap between the tubes which will rest against the septum posteriorly.
    • ii. Once the stents are brought to rest in the nose, then the anterior ends are drawn through a silicone plate with precut holes and then bonded in place with silicone adhesive.
    • iii. The excess tubing anteriorly is cut off and these children are left in their stents for 6-8 weeks.

  • 2. Morgan DW and Bailey CM are proponents of using a Portex endotracheal tube cut to the appropriate length and shape.
    • i. The tube is folded in half and placed in the nose with the open ends through the newly created choanea.
    • ii. The bend in the stent is the opened on one side over the columellar bridge.
    • iii. The stent is secured in place by passing a nylon ligature down the inside of each tube and around the back of the nasal septum, tied over the columellar bridge of the stent.
    • iv. The stent is removed after 6 weeks and the patient is continued on nasal steroid drops for 2 weeks. The patient is examined under general anesthesia 6 weeks later and any granulation tissue or scaring is removed at that time.

  • 3. Grundfast et al., has recently devised a even more creative way to stent his patients with good success.
    • i. Silastic tubing is used to make the stent. The size of the tubing should be the largest diameter tubing that fits securely into the nose.
    • ii. An oval shaped window is first cut with a scalpel into the tube at a site equidistant from both ends. This window will serve as the common open posterior portion of the two stents.
    • iii. The tubing is then folded upon itself forming two parallel hollow tubes with a silastic bridge at one end.
    • iv. A double-armed pacemaker wire is then passed through the medial (septal) wall of the stent on one side and brought out through the posterior window. The wire should enter the stent approx. one cm from the posterior window.
    • v. The wire is then passed through the opposite posterior window and out approx. one cm. from the opening on the opposite side at a corresponding entry position of the medial wall.
    • vi. The stent is then inserted into the nose via Robnels attached to the two wire ends in the mouth and then brought out back through the nose(just like a posterior pack).
    • vii. The U-shaped Silastic tubing is now seeded in the posterior on third of the nose within the newly created choanea.
    • viii.To secure this in place, the surgeon makes a sublabial incision and identifies the nasal spine.
    • ix. The free ends of each wire are threaded on two separate Keith needles and passed separately through the floor of the nose and into the sublabial incision.
    • x. After the position of the stent is verified with a mirror or 90 degree telescope, the wires are tied securely anterior and inferior to the bony anterior nasal spine. The incision is closed with 4-0 Vicryl.
    • xi. Under general or local anesthesia depending upon the age of the patient, the sublabial incision is reopened, the wire is cut and the stent is grasped with a right angle and removed.
    • xii. The author feels this is a very useful technique and the child is not deformed by the stent for the 6-8 weeks or longer that may be required. (Especially in school age patients who are having a unilateral choanal atresia repaired and wish to return to school without being teased).

  • B. Wound Care:
    • 1. The parents must be taught to maintain the stents with frequent suction and a saline-moistened pipe cleaner or cotton applicator 3 to 6 times per day.
    • 2. Antibiotics and decongestants are prescribed for any purulent rhinitis episodes.
    • 3. Many authors leave the children on prophylactic antibiotics (ie.EES) while the stents are in place.

  • C. Follow Up:
    • 1. The patients are followed up every 2 weeks or more frequently if needed while the stents are in place.
    • 2. Then once the stents are removed, the patients are seen weekly for the first 2-3 weeks to treat and granulation tissue and for suctioning. Any dilation of choanea can then be done at the earliest indication of stenosis.

VII. Conclusion

• A. Membranous Choanal Atresia - most of these cases can be repaired via a transnasal approach with good success rate with only one procedure.
• B. Unilateral Bony Choanal Atresia - These patients are usually not a respiratory emergency. Therefore they can be followed closely and planned to have the definitive repair at 5-6 yrs. of age if no other medical problems preclude waiting. There is still controversy as to which procedure to perform, but many of the recent papers encourage the use of Endoscopic transnasal surgery for the definitive repair.
• C. Bilateral Bony Choanal Atresia - These patients are usually in respiratory distress when you are asked to see them and require an oral airway of some type(ie. McGovern nipple) and to begin on gavage feeding while a CT scan is obtained to help establish a plan for surgery. There are still two camps divided on this issue of which is the best definitive procedure for these patients. The CT scan often helps tremendously in the decision of which type of surgery is indicated and when to proceed.
  • 1. The transnasal proponents feel that when there is only a minimal bony atresia plate and not much lateral bony overgrowth, then they can proceed with the transnasal approach as the definitive procedure. These doctors also feel that the transnasal approach can be done initially in the first few days of life with minimal morbidity or mortality as a prophylactic measure knowing that in 2-3 months the definitive procedure will need to be transpalatal.
  • 2. The transpalatal proponents believe that this is the most reliable and successful method to repair bilateral bony choanal atresia with one operation. Therefore, they recommend an oral airway for 1 to 3 months or until the child is mature enough to undergo surgery. (The exact weight or age of the child preop is not clearly defined in the literature. Some authors operate at one month and others wait until 3 months of age).

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