Frequency of canalis sinuosus and its anatomic variations in cone beam computed tomography images / Frecuencia de canalis sinuosus y sus variaciones anatómicas en imágenes de tomografía computarizada de haz cónico

The aim of this paper was to determine the frequency of Canalis Sinuosus (CS) and its anatomic variations. A total of 236 cone beam computed tomography (CBCT) images were studied. Characteristics of the canal such as its form, pathway and diameter were analyzed. The CS was clearly visualized in 100 % of the images with variations in the canal observed in up to 46 % of the cases. In 79 % of the cases the variation was found to be bilateral. The most common variation was an increase in the diameter (> 1mm) of the CS. Considering that the anterior region of the middle third of the face is a common place for clinical interventions, this study supports the need to perform a thorough evaluation of the maxillary region prior to clinical interventions in order to prevent complications such as direct or indirect injury to the anterior superior alveolar neurovascular bundle contained within the CS.

El objetivo de este trabajo fue determinar la frecuencia de Canalis Sinuosus (CS) y sus variaciones anatómicas. Se estudiaron un total de 236 imágenes de tomografía computarizada de haz cónico (CBCT). Se analizaron las características del canal, como su forma, vía y diámetro. El CS se visualizó claramente en el 100 % de las imágenes, observándose variaciones en el canal en hasta el 46 % de los casos. En el 79 % de los casos la variación fue bilateral. La variación más común fue un aumento en el diámetro (> 1 mm) de la CS. Teniendo en cuenta que la región anterior del tercio medio de la cara es un lugar común para las intervenciones clínicas, este estudio apoya la necesidad de realizar una evaluación exhaustiva de la región maxilar antes de las intervenciones clínicas para prevenir complicaciones como lesiones directas o indirectas a el haz neurovascular alveolar superior anterior contenido dentro de la CS.

Computed tomography evaluation of the morphometry and variations of the infraorbital canal relating to endoscopic surgery / Computed tomography evaluation of the morphometry and variations of the infraorbital canal relating to endoscopic surgery

Abstract Introduction: The course of the infraorbital canal may leave the infraorbital nerve susceptible to injury during reconstructive and endoscopic surgery, particularly when surgically manipulating the roof of the maxillary sinus. Objective: We investigated both the morphometry and variations of the infraorbital canal with the aim to show the relationship between them relative to endoscopic approaches. Methods: This retrospective study was performed on paranasal multidetector computed tomography images of 200 patients. Results: The infraorbital canal corpus types were categorized as Type 1: within the maxillary bony roof (55.3%), Type 2: partially protruding into maxillary sinus (26.7%), Type 3: within the maxillary sinus (9.5%), Type 4: located anatomically at the outer limit of the zygomatic recess of the maxillary bone (8.5%). The internal angulation and the length of the infraorbital canal, the infraorbital foramen entry angles and the distances related to the infraorbital foramen localization were measured and their relationships with the infraorbital canal variations were analyzed. We reported that the internal angulations in both sagittal and axial sections were mostly found in infraorbital canal Type 1 and 4 (69.2%, 64.7%) but, there were commonly no angulation in Type 3 (68.4%) (p < 0.001). The length of the infraorbital canal and the distances from the infraorbital foramen to the infraorbital rim and piriform aperture was measured as the longest in Type 3 and the smallest in Type 1 (p < 0.001). The sagittal infraorbital foramen entry angles were detected significantly smaller in Type 3 and larger in Type 1 than that in other types (p = 0.003). The maxillary sinus septa and the Haller cell were observed in 28% and 16% of the images, respectively. Conclusion: Precise knowledge of the infraorbital canal corpus types and relationship with the morphometry allow surgeons to choose an appropriate surgical approach to avoid iatrogenic infraorbital nerve injury.

Resumo: Introdução: O trajeto do canal infraorbitário pode predispor o nervo infraorbitário a lesões durante cirurgias reconstrutoras e endoscópicas com manipulação do teto do seio maxilar. Objetivo: Investigamos a morfometria e as variações do canal infraorbitário e objetivamos demonstrar a relação entre elas, visando as abordagens endoscópicas. Método: Este estudo retrospectivo foi realizado em imagens de tomografia computadorizada multidetectora de seios paranasais de 200 pacientes. Resultados: Os tipos de corpos do canal infraorbitário foram categorizados como Tipo 1; inseridos no teto ósseo maxilar (55,3%), Tipo 2; projetando-se parcialmente dentro do seio maxilar (26,7%), Tipo 3; dentro do seio maxilar (9,5%), Tipo 4; localizado anatomicamente no limite externo do recesso zigomático do osso maxilar (8,5%). A angulação interna e o comprimento do canal infraorbitário, os ângulos de entrada do forame infraorbitário e as distâncias relacionadas à localização do forame foram medidos e suas relações com as variações do canal infraorbitário foram analisadas. Observamos que as angulações internas em ambos os cortes sagital e axial foram encontradas em sua maioria em canais infraorbitários Tipo 1 e 4 (69,2%, 64,7%) e, no geral, não houve angulação no canal Tipo 3 (68,4%) (p < 0,001). O comprimento do canal infraorbitário e as distâncias desde o forame infraorbitário até o rebordo infraorbitário e a abertura piriforme foram medidos e os mais longos foram identificadas no Tipo 3 e os mais curtos no Tipo 1 (p < 0,001). Os ângulos de entrada do forame infraorbitário em projeção sagital foram significativamente menores no Tipo 3 e maiores no Tipo 1, em relação aos outros tipos (p = 0,003). Septos nos seios maxilares e as células de Haller foram observados em 28% e 16% das imagens, respectivamente. Conclusão: O conhecimento preciso dos tipos de corpo do canal infraorbitário e a relação com a morfometria permitem que o cirurgião escolha uma abordagem cirúrgica apropriada para evitar lesões iatrogênicas do nervo infraorbitário.

Location and classification of Canalis sinuosus for cone beam computed tomography: avoiding misdiagnosis

Abstract The aim of this study was to assess the presence, location and, multiplanar distance of the canalis sinuosus (CS) between the incisive foramen and the anterior maxillary alveolar ridge using cone beam computed tomography (CBCT). Therefore, 500 CBCT maxillary images obtained from male and female patients aged 20 to 80 years were selected to assist in the dental treatment. Low-quality tomographic images were discarded. All images were captured with the i-CATTM Classic tomograph and assessed using the XoranCatTM software. The axial sections were analyzed at the incisive foramen in order to verify the CS presence in laterality and location. Furthermore, linear measurements of the nasal cavity floor, buccal cortical bone, and alveolar ridge crest were made. All the collected data were statistically analyzed. Results show a variation of the CS in relation to the classification and distance of anatomical structures, but no significant difference between the right and left sides. It should be highlighted that CBCT is necessary before invasive procedures in order to preserve important anatomical structures. In conclusion, the location of the CS varies in relation to the alveolar ridge crest and buccal cortical bone, assuming that it is going to be located by the upper lateral incisor palatine.