2019, Number 3
Aplasia of the maxillary sinus. A case report
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Language: English/Spanish [Versión en español]
References: 9
Page: 159-162
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ABSTRACT
Maxillary sinus aplasia is a rare anomaly usually diagnosed as a finding in imaging studies requested for the treatment of other conditions. The etiology is uncertain, although a possible relationship with a specific history of abnormalities in intrauterine development, reduction in nasal ventilation due to sinusitis in the first year of life, trauma, surgery, systemic disease, or neoplasm has been suggested. Anatomical defects and abnormalities such as position or absence of the concha bullosa as well as of the unciform apophysis may represent another factor contributing to the development of maxillary sinus hypoplasia-agenesis. The development of the maxillary sinus plays an important role in the growth and development of adjacent structures, such as bones and facial muscles. Here we present the case of an 18-year-old male patient with facial asymmetry secondary to maxillary sinus aplasia.INTRODUCTION
The maxillary sinus begins its growth in the lateral wall of the ethmoid area of the nasal capsule at the third month of intrauterine life, being the first of the paranasal sinuses to appear. The maxillary cavity is identifiable at week 16 of gestation.1
The maxillary sinus is usually the largest of the paranasal sinuses, with an approximate volume of 6-8 cm3, although its size varies depending on the individual and her/his age. It occupies most of the maxillary body.2
Maxillary sinus aplasia (MSA) can be defined as a failure in sinus development, which is an extremely rare condition.2
The accurate etiology is uncertain, although MSA has been suggested to be related to abnormalities in intrauterine development or reduction in nasal ventilation due to sinusitis in the first year of life. It may also be associated with trauma, surgery, systemic disease or neoplasm.3 The absence of the antrum may lead to abnormal maxillary growth, with esthetic consequences such as flattening of the nasomaxillary region.4
In a simple radiograph, only opacity in the affected sinus is observed, which may confuse MSA with other entities. An adequate diagnosis requires a CT scan or CBCT using thin cuts; also, a bone window scan can confirm the complete absence of the maxillary sinus and outline the structural abnormalities of the nasal cavity. It is important not to confuse MSA with severe hypoplasia of the maxillary sinus.2,5
CLINICAL CASE
An 18-year-old male patient was referred to the maxillofacial surgery service of the National Institute of Respiratory Diseases by the orthodontic department of a university dental clinic for assessment of facial asymmetry. The patient was in his fourth year of orthodontic treatment for camouflage orthodontics. The patient did not refer relevant medical history, including surgical or trauma history. On physical examination, the patient showed good neurological condition, normocephalic skull, proper hair insertion, dystopia of left eye (enophthalmos), hypoplasia of left nostril and left external ear, depression in left infraorbital region (Figure 1), class III concave profile, maxillary canting, and unaltered TMJ region with adequate mandibular movements. Intraorally it was observed Angle's class III malocclusion, negative overbite, and dental malposition. Thin-cut CT scan and bone window were requested. Coronal slices showed an increase in the volume of the left orbit as well as complete absence of the left maxillary sinus, deviation of the nasal septum and hyperplasia of inferior left turbinate. Axial slices corroborated left maxillary sinus aplasia and 3D reconstruction showed in the anterior view a depression of the anterior wall of the maxillary bone (Figure 2). The treatment plan consisted of the harvest and application of autologous graft of anterior iliac crest to correct volume loss in the anterior region of the maxilla and orthognathic surgery to correct the dentoskeletal discrepancy.
DISCUSSION
The CT scan examination is effective for detecting incidental findings in the maxillofacial area,5 the maxillary sinus being one of the most common sites.6 Most reported MSA cases are discovered when imaging studies are conducted for other reasons. In the reported case, the clinical characteristics suggested an obvious skeletal alteration which was corroborated with the imaging studies.
The size, location and uni/bilaterality of the concha bullosa correlate with the existence of maxillary hypoplasia, especially in terms of the existence, medialization or lateralization of the unciform apophysis.7
The unciform apophysis may be laterally displaced in some cases of maxillary sinus hypoplasia. When this occurs, the nasal side wall tends to lateralize below the middle turbinate.7 When the blockage of maxillary sinus takes place in childhood, before the age of 10, there is usually an absence of unciform apophysis and a minimum vestige of maxillary sinus, allowing the orbit to grow.8 The blockage of the maxillary sinus during adolescence is usually related to inflammatory or obstructive nasosinusal pathology, such as septal deviation or chronic sinusitis.8
Bolger et al. classify the structural alterations of the unciform apophysis and the maxillary infundibulum and relate the severity of maxillary sinus hypoplasia to the lack of development of the unciform process and a poor definition of the infundibulum passage.9
CONCLUSIONS
The maxillary sinus is importantly involved in the normal development of the maxilla and hence of other facial bones. MSA is a rare condition; yet, when it occurs it usually brings about esthetic and functional alterations for the patient. Dentists and physicians related to the area must be familiar with this anomaly in order to make a timely diagnosis and proper treatment planning.
REFERENCES
AFFILIATIONS
1 Jefe del Departamento de Cirugía Maxilofacial. Instituto Nacional de Enfermedades Respiratorias "Ismael Cosío Villegas".
2 Adscrito al Servicio de Cirugía Maxilofacial. Instituto Nacional de Enfermedades Respiratorias "Ismael Cosío Villegas".
3 Pasante en Estomatología. Instituto Nacional de Enfermedades Respiratorias "Ismael Cosío Villegas".
CORRESPONDENCE
Ilan Vinitzky Brener. E-mail: ilanvinitzky@hotmail.comReceived: Junio 2019. Accepted: Agosto 2019.