Practice Essentials
The nasopharynx is defined as the superior portion of the pharynx that lies between the choanae of the nasal cavity and the oropharynx (ie, the level of the posterior limit of the soft palate). Stenoses of this area are rare. They are classified according to their etiology, which may be primary (ie, due to a disease process) or secondary (ie, iatrogenic). However, most current cases are understood to be secondary to tonsillectomy, adenoidectomy, uvulopalatoplasty, or radiotherapy for nasopharyngeal carcinoma.
Because of a high incidence of recurrence, the treatment of this condition is challenging. Even with optimal planning and surgical technique, many patients require repeat operations to obtain a satisfactory result. Therefore, many treatment modalities are being tried to cure this problem.
Nasopharyngeal stenosis (NPS) should not be confused with choanal atresia. Choanal atresia is a congenital deformity that causes a narrow or completely obstructed airway at the choanae that often extends into the nasal cavity. [1] Generally, choanal atresia includes a bony component. Conversely, nasopharyngeal stenosis (NPS), by definition, is outside of the nasal cavity, is not congenital, and is caused by scar tissue secondary to a disease process or traumatic insult.
An image depicting complete nasopharyngeal stenosis can be seen below.
Complete nasopharyngeal stenosis.
Signs and symptoms of nasopharyngeal stenosis
These include the following:
-
Mouth breathing
-
Snoring
-
Rhinorrhea
-
Hyponasality
-
Dysphagia
-
Otalgia
-
Loss of hearing (otitis media)
-
Anosmia
Workup in nasopharyngeal stenosis
Imaging studies
Computed tomography (CT) scanning and virtual endoscopy of the nasopharyngeal region can enable diagnosis and proper evaluation of the degree and extent of stenosis.
Diagnostic procedures
Preoperative rigid nasal endoscopic examination and/or flexible nasopharyngolaryngoscopy are essential to assess the thickness, nature, and extent of the stenosis and the deformity of the posterolateral aspect of the nasal cavity, as well as to identify anatomic deformities at the level of the vomer and the posterior nasal cavity. Identifying concurrent upper aerodigestive tract stenosis, which may be present, is important.
Histologic findings
Histology of the resected scar tissue from the stenotic segment usually reveals respiratory epithelial-lined stromal tissue with chronic inflammation, edema, and fibrosis.
Management of nasopharyngeal stenosis
Many surgical approaches have been suggested for nasopharyngeal stenosis, including the following [2, 3, 4] :
-
Transnasal - Provides narrow exposure, making raising of the mucosal flaps difficult; also, injury to the Eustachian tube and the skull base is possible
-
Transpalatal - Offers excellent exposure and a high success rate but is time consuming and may be associated with bleeding and sequelae like palatal muscle dysfunction, palatal fistula, and maxillofacial disturbances [5]
-
Transantral
-
Sublabial transnasal endoscopic
-
Transseptal
History of the Procedure
Historically, many procedures have been used in an attempt to correct nasopharyngeal stenosis (NPS).
-
Simple dilatation is generally not successful except in mild partial occlusion.
-
A seton technique has been used with limited success. A heavy silk suture or other seton material is put in place, and, as it passes through the scar tissue, epithelialization of the tract develops. This tract can then be divided with the hope that the epithelialization prevents the stenosis from recurring.
-
One reportedly successful technique involves division of the obstruction and resection of the scar tissue, using a stent to maintain the opening. The principle is similar to that used in correction of choanal atresia. Many variations of this procedure have been performed, including one in which a split-thickness graft is used to help resurface the raw areas.
-
One of the most successful methods of repair is division of the obstruction and resection of the scar tissue along with resurfacing using rotational mucosal flaps.
-
Since 2008, endoscopic transnasal repair using either powered shavers or lasers has become a popular method of repairing nasopharyngeal stenosis.
-
Endoscopic transnasal CO2 laser ablation of the stenosis followed by balloon dilation and mitomycin application has been reported. [6]
Problem
Patients with nasopharyngeal stenosis could frequently suffer from other significant morbidities like phonatory changes, sleep disordered breathing and otologic disturbances e.g. secretory otitis media and hearing loss. [2, 7, 8]
Epidemiology
Frequency
Nasopharyngeal stenosis (NPS) is relatively rare. The true incidence of this rare condition is difficult to assess. In 1944, in a 10-year review of 100,000 tonsillectomies and adenoidectomies at the Manhattan Eye, Ear, and Throat Hospital, Imperatori found only 3 cases. [9] This condition has no sex predilection.
Etiology
Most cases of nasopharyngeal stenosis (NPS) are caused by inexpert surgery and postsurgical scarring. Overly enthusiastic adenoidectomies or uvulopalatoplasties are the usual operations that lead to nasopharyngeal stenosis (NPS). However, tonsillectomies, surgery of the soft palate, and pharyngeal surgeries to treat velopharyngeal incompetence can also cause nasopharyngeal stenosis (NPS). The literature prior to 1929 reports that most cases were due to the gumma of tertiary syphilis of the mouth, pharynx, and palate and the treatment of these lesions with caustic chemicals.
Giannoni et al (1998) have reported 9 cases of nasopharyngeal stenosis in children following adenoidectomy with KTP Laser. Many reports have been published of nasopharyngeal stenosis following radiotherapy for nasopharyngeal carcinoma. [10, 3, 4, 2, 11] Other rare causes in the literature include rhinoscleroma, lupus, diphtheria, scarlet fever, bullous pemphigoid, tuberculosis, and acid burns.
A retrospective study by Kouga et al indicated that in patients with craniosynostosis-related respiratory problems, nasopharyngeal stenosis is more often the culprit in those with Pfeiffer syndrome than in patients with Crouzon or Apert syndrome. [12]
Pathophysiology
Nasopharyngeal stenosis (NPS) may appear months to years after adenoidectomy or uvuloplasty or radiotherapy. It results from excess mucosal removal or scarring during surgery or radiotherapy followed by scar contracture and maturation. The degree and extent of the stenosis may vary from patient to patient. The scar tissue may cause a circumferential narrowing, a web, or bands. A discrete circumferential web or a long stenosed segment that forms a narrow tunnel several centimeters long may be present.
Presentation
The severity of symptoms is related to the degree of nasopharyngeal stenosis (NPS). The history includes a traumatic insult (iatrogenic, traumatic, or infective) to the nasopharynx. Symptoms include mouth breathing, snoring, rhinorrhea, hyponasality, dysphagia, otalgia, loss of hearing (otitis media), and anosmia. If these symptoms develop following a surgical procedure in the nasopharynx or radiotherapy, nasopharyngeal stenosis (NPS) should be considered.
Upon examination, the mucosa of the nasal airway may be blue and boggy, as is seen with nasal obstruction. Airflow through the nostrils may be reduced or eliminated. Scar tissue that involves the soft palate and tonsil pillars may be visible. A postnasal mirror or a rigid or flexible nasendoscope aids in making the stenosis visible.
Indications
The severity of the symptoms must be balanced against the difficulty of surgical repair and the possibility of recurrence and multiple operations. Many patients are young and have to live with potentially progressive symptoms for many years. Symptoms are usually severe at presentation, and surgical intervention is usually required.
Relevant Anatomy
The nasopharynx can be thought of as an essentially cuboidal space. The roof is formed by the base of the skull and the sphenoid sinus, anteriorly bounded by the choanae and posterior portion of the vomer. The floor consists of the superior surface of the soft palate and uvula. Incorporated into the lateral walls are the Eustachian tube orifices and the Rosenmüller fossae. The posterior wall is the superior extension of the posterior pharyngeal wall.
The mucosa of the nasopharynx is the respiratory type. The midline usually contains a large deposit of lymphoid tissue that often extends into the Rosenmüller fossae.
The shape of the nasopharynx changes with respiration and deglutition. During respiration, the soft palate is drawn away from the posterior pharyngeal wall to open an airway. During deglutition, the palate elevates and contacts the nasopharynx so that food and fluid do not pass into the nose.
Contraindications
Surgical correction of nasopharyngeal stenosis (NPS) may be contraindicated in the presence of the patient's comorbidities and inability to tolerate anesthesia or surgery, but the symptoms, which are usually severe at presentation, usually require surgical intervention.
-
Complete nasopharyngeal stenosis.
