Pyriform aperture stenosis repair in infants

Congenital nasal pyriform aperture stenosis (CNPAS) is a rare developmental anomaly. The true incidence is unknown; however, it is less commonly seen than choanal stenosis or choanal atresia. It is considered a mild variant of holoprosencephaly and is frequently associated with a solitary median maxillary central incisor.^{,  ,}  If this radiologic finding is present, additional midline defects in the holoprosencephaly spectrum can be seen, including an absent upper labial frenulum, absence of the corpus callosum, and pituitary gland abnormalities.

CNPAS was first described in adults in 1952 by Douglas. It was described radiologically by Ey et al and described clinically in infants by Brown et al. Given that neonates and infants are obligate nasal breathers for up to the first 8 months of life, the most common presentation of CNPAS is respiratory distress, apnea, nasal congestion, feeding difficulty, and cyclical cyanosis. The differential diagnosis includes choanal atresia, mid-nasal stenosis, nasolacrimal duct cyst, congenital septal deviation or other intranasal masses. Unlike in choanal atresia, which is often suspected due to failure of the ability to pass an 8 Fr flexible suction catheter through the nose, in CNPAS the obstruction is more anterior and there is usually an inability to pass a 5 Fr flexible suction or a 2.2 mm nasopharyngeal scope into the nose at all.

Maxillofacial computed tomography is the diagnostic modality of choice and is required to make the diagnosis of CNPAS. Radiographically, the normal pyriform aperture measures 11 mm or greater in diameter at birth. Anything less than this is believed to be diagnostic of CNPAS. The most medial structures within this narrowed nasal cavity are the inferior turbinates. The pyriform aperture is comprised of the horizontal processes of the maxilla inferiorly, the frontal processes of the maxilla inferolaterally and the nasal bones superolaterally. The aperture is divided in the midline by the anterior nasal spine and septum. A solitary median maxillary central incisor is found in 34%-65% of infants with CNPAS. Patients with this finding will require magnetic resonance imaging of the brain to evaluate for associated features of holoprosencephaly, as well as an endocrinology evaluation (Figure 1).

Conservative management of CNPAS includes nasal decongestant drops, nasal steroid drops (such as 0.1% nasal dexamethasone) or use of a McGovern nipple to allow oral respiration.^,  Some children with mild CNPAS may eventually outgrow the disorder and will not need surgical intervention. Surgery is indicated when conservative management fails and the child continues to experience respiratory distress or poor weight gain, although no concrete indications exist. Visvanathan and Wynne have suggested that a pyriform aperture width of 5 mm or less is an indication for surgery.

Various methods of pyriform aperture stenosis repair have been described. Brown et al described the sublabial, or maxillary vestibular approach in their landmark paper on the subject. The nasal dilation technique described below was initially described by Wine et al. Other novel techniques include balloon dilation of the pyriform aperture as detailed by Gungor and Beiersen. The nasal dilation and sublabial approaches are detailed later.

The nasal dilation approach is as follows. The child is taken to the OR and placed under general orotracheal anesthesia in the supine position. All pressure points are padded and the patient prepped and draped in a sterile fashion. In this technique, a series of successfully larger Hegar cervical dilators are introduced into the nose (Figure 2). This enlarges the nasal airways by creating isolated inferior turbinate outfractures. Dilation commences with a 2-mm dilator and progresses to a maximum of a 5- or 6-mm dilator. Stenting is not routinely performed. All patients are taken to the neonatal intensive care unit and treated with nasal oxymetazoline for 3 days, nasal saline, and nasal corticosteroids. The procedure is deemed successful if it (and associated medical management) is associated with the resolution of respiratory and feeding problems, allows for outpatient treatment, and obviates the need for a sublabial approach. Results with this technique are promising, to the point where it has become the first line approach for surgical management of CNPAS in our institution.

If no improvement is seen after nasal dilation, we proceed with the sublabial approach.^,  The child is taken to the OR and placed under general orotracheal anesthesia in the supine position. All pressure points are padded and the patient prepped and draped in a sterile fashion with the nose, midface, and mouth uncovered. Loupe or microscopic magnification is used, as are otologic instruments and a microdrill. The maxillary gingival sulcus is infiltrated with 1-2 mL of 0.5% lidocaine with 1:200,000 epinephrine for hemostasis in newborns (maximum dose should be calculated based on the patient’s weight). A 1% lidocaine with 1:100,000 epinephrine is used in children older than one year of age. In addition, cottonoid patties with a topical vasoconstrictor such as 0.5% oxymetazoline are placed intranasally for additional vasoconstriction of the nasal mucosa. An approximately 1.5 cm incision is made in the maxillary vestibule with a scalpel or needlepoint cautery and carried down to the bone of the maxilla (taking care to leave an adequate cuff for mucosal closure) (Figure 3). Periosteal elevators are used to gently elevate the periosteum to expose the pyriform aperture. The mucosa of the nasal floor, lateral nasal wall and inferior turbinate are carefully elevated until the inferior bony pyriform aperture (which is comprised of the ascending processes of the maxilla) is exposed bilaterally. The anterior nasal spine is left attached to the septal cartilage. Using an otologic drill with a 2 and 3 mm diamond burr and copious irrigation, the bony pyriform aperture is enlarged laterally using smooth, polishing strokes (Figure 4). A protector for the mucosa (ie, foil from a suture pack) is optional but can be helpful to avoid damage to the mucosa from the burr. A very small amount of bone needs to be removed, usually only 1-2 mm. One may also perform concurrent inferior turbinate reduction to further enlarge the nasal airways. The endpoint is reached when a 3.5 cuffless endotracheal tube can fit through the nostril bilaterally. The maxillary vestibular mucosa is closed in layers with absorbable suture, and a mucosal releasing incision is made in the nasal floor bilaterally to accommodate the placement of intranasal stents. Postoperative stenting is controversial. After bone removal, stenting is typically performed with a 3.5 cuffless endotracheal tube for 5-28 days. We anchor the stent by suturing it through the columella with a nonabsorbable suture. Potential problems with stenting include patient discomfort and granulation tissue formation as well as nasal alar or columellar pressure necrosis related to the suture. Some surgeons use ciprofloxacin-dexamethasone drops in an off-label fashion to deter granulation tissue formation. Other surgeons do not stent at all, or stent only overnight. Smith and colleagues recently described the use of mometasone furoate-eluting sinonasal stents after a sublabial approach, with promising results. The current practice at our institution is to stent.

Patients are taken to the intensive care unit postoperatively, where they are started on nasal corticosteroids and saline drops. Treatment in the neonatal intensive care unit continues until the patient has obtained all nutritional needs orally and is breathing comfortably. The nasal corticosteroids and saline are continued as outpatient medications. If a stent was placed, the patient is seen back in 1-2 weeks to ensure that the family is not having any trouble suctioning the stent and that the stent is in good position. Antibiotics are started postoperatively if a stent was placed, typically for the duration that the stent remains in place. If no stent was placed, the patient is seen back in 2-4 weeks.

Potential complications of the nasal dilation approach include scarring and restenosis.

Potential complications of the sublabial approach include violation of the nasal mucosa, injury to un-erupted tooth buds, injury to the nasolacrimal duct, injury to the septum, oronasal fistula, alar and columellar pressure necrosis, bleeding, infection, granulation tissue formation, stent plugging, and restenosis.

CNPAS is a rare developmental anomaly that can potentially lead to life-threatening nasal obstruction. If associated with a solitary median maxillary central incisor, it is important to obtain an magnetic resonance imaging to evaluate for additional midline defects in the holoprosencephaly spectrum. If refractory to conservative management, several effective methods of surgical correction exist.

The authors report no proprietary or commercial interest in any product mentioned or concept discussed in this article.

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