The relationship of the medial roof and the posterior wall of the maxillary sinus to the sphenoid sinus: a radiologic study / Relação do teto medial e parede posterior do seio maxilar como o seio esfenoidal: estudo radiológico

Abstract Introduction: The medial maxillary sinus roof is a ridge formed by the superior margin of the maxillary sinus antrostomy. The posterior wall of the maxillary sinus is always included in operative fields. Objective: To perform a radiologic study assessing the utility of the medial maxillary sinus roof and the posterior wall of the maxillary sinus as fixed landmarks for providing a safe route of entry into the sphenoid sinus. Methods: We reviewed 115 consecutive paranasal sinus Computed Tomographic scans (230 sides) of Korean adult patients performed from January 2014 to December 2014. Using the nasal floor as a reference point, the vertical distances to the highest point of the medial maxillary sinus roof, the sphenoid ostium and anterior sphenoid roof and floor were measured. Then the vertical distances from the highest point of the medial maxillary sinus roof to the sphenoid ostium and anterior sphenoid roof and floor were calculated. The coronal distance from the posterior wall of the maxillary sinus to the sphenoid ostium was determined. Results: The average height of the highest point of the medial maxillary sinus roof relative to the nasal floor was measured to be 33.83 ± 3.40 mm. The average vertical distance from the highest point of the medial maxillary sinus roof to the sphenoid ostium and anterior sphenoid roof and floor was 1.79 ± 3.09 mm, 12.02 ± 2.93 mm, and 6.18 ± 2.88 mm respectively. The average coronal distance from the posterior wall of the maxillary sinus to the sphenoid ostium was 0.78 mm. The sphenoid ostium was behind the coronal plane of the posterior wall of the maxillary sinus most frequently in 103 sides (44.4%). It was in the same coronal plane in 68 sides (29.3%) and in front of the plane in 61 sides (26.3%). Conclusions: The medial maxillary sinus roof and the posterior wall of the maxillary sinus can be used as a reliable landmark to localize and to enable a safe entry into the sphenoid sinus.

Resumo Introdução: O teto medial do seio maxilar é uma crista formada pela margem superior da antrostomia do seio maxilar. A parede posterior do seio maxilar é sempre incluída em campos cirúrgicos. Objetivo: Fazer estudo radiológico para avaliar a utilidade do teto medial do seio maxilar e da parede posterior do seio maxilar como referências anatômicas fixas para fornecer uma via segura de abordagem ao seio esfenoidal. Método: Foram analisados 115 exames de tomografia computadorizada consecutivos dos seios paranasais (230 lados) de pacientes adultos coreanos feitos de janeiro de 2014 a dezembro de 2014. Com o uso do assoalho nasal como ponto de referência, as distâncias verticais entre o teto medial do seio maxilar e o óstio esfenoidal e entre o teto e o assoalho esfenoidal anterior foram medidos. Em seguida, as distâncias verticais do ponto mais alto do teto medial do seio maxilar e o óstio esfenoidal e entre o teto e ao assoalho esfenoidal anterior foram medidas. A distância coronal da parede posterior do seio maxilar ao óstio esfenoidal foi determinada. Resultados: A altura média do ponto mais alto do teto medial do seio maxilar em relação ao assoalho nasal foi medida como 33,83 ± 3,40 mm. A distância vertical média do ponto mais alto do teto medial do seio maxilar até o óstio esfenoidal e do teto ao assoalho esfenoidal anterior foi de 1,79 ± 3,09 mm, de 12,02 ± 2,93 mm e 6,18 ± 2,88 mm, respectivamente. A distância coronal média da parede posterior do seio maxilar ao óstio esfenoidal foi de 0,78 mm. O óstio esfenoidal estava por trás do plano coronal da parede posterior do seio maxilar com mais frequência em 103 lados (44,4%). O mesmo se encontrava no plano coronal em 68 lados (29,3%) e na frente do plano em 61 lados (26,3%). Conclusões: O teto medial do seio maxilar e a parede posterior do seio maxilar podem ser usados como pontos de referência confiáveis para localizar e possibilitar uma abordagem segura ao seio esfenoidal.

The Relationship of the Medial Maxillary Sinus Roof to the Sphenoid and Posterior Ethmoid Sinuses in Korean: A Radiologic Study / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: The aim of this study was to perform radiologic study assessing the utility of the medial maxillary sinus roof (MMSR) as a reference point for providing a safe route of entry into the sphenoid and the posterior ethmoid sinuses in Korean patients. SUBJECTS AND METHOD: We retrospectively reviewed 82 consecutive ostiomeatal computed tomographic scans of Korean adult patients performed from January 2014 to December 2014. Using the nasal floor as a reference point, the vertical distances to the highest MMSR, natural sphenoid ostium, anterior sphenoid roof and floor and posterior ethmoid skull base were measured. Then the vertical distances from the highest MMSR to the sphenoid ostium, anterior sphenoid roof and floor and posterior ethmoid skull base were calculated. The maxillary sinus to posterior ethmoid height ratio was calculated. RESULTS: The average height of the highest MMSR relative to the nasal floor was measured to be 33.95+/-3.36 mm. The vertical distance from the highest MMSR to the natural sphenoid ostium, anterior sphenoid roof and floor and posterior ethmoid skull base was 1.87+/-3.52 mm, 11.77+/-3.30 mm, 6.09+/-3.16 mm, and 15.46+/-3.07 mm respectively. The mean ratio of the maxillary sinus to the posterior ethmoid height was 2.3+/-0.56. CONCLUSION: The MMSR can be used as a reliable landmark to localize the natural sphenoid ostium and to enable a safe entry into the posterior ethmoid. Moreover, it provides a reasonable margin of safety from the skull base.