Cone beam computed tomographic evaluation of infraorbital canal protrusion into the maxillary sinus and its importance for endoscopic surgery

Abstract Objective: The aim of this retrospective study is to investigate the prevalence of Infraorbital Canal Protrusion (ICP) degree into the maxillary sinus and its relationship with variations in adjacent structures on Cone Beam Computed Tomography (CBCT) images. Methods: 350 CBCT images (700 Infraorbital Canal [IC]) were evaluated retrospectively. ICP was divided into 3 subtypes according to the protrusion degree. The correlation between IC types and variations in adjacent anatomical structures (Haller cell, middle nasal concha pneumatization, maxillary sinus mucosal thickening and septa) was evaluated. The distance between Infraorbital Canal and Cnine Root (IC-CR) was also measured. For type 3, measurements were performed on IC as the length of the bony septum from the IC to the Mxillary Sinus Wall (IC-MSW), the distance from the inferior orbital rim, where the IC begins to protrude into the maxillary sinus (IOR-ICP), the vertical distance from the IC to the Maxillary Sinus Roof (IC-MSR) and Floor (IC-MSF). Results: The prevalence of type 1, 2 and 3 was 62.9%, 29.1%, and 8% respectively. IC-CR was 10.2, 10.7 and 11.4 mm in type 1, 2 and 3, respectively. IC-MSW, IOR-ICP, IC-MSRand floor IC-MSF was 3.8, 10.9, 7.4 and 27.7mm, respectively. On the right and left side, statistically significant correlation was found between IC types and the presence of the Haller cell and sinus septa. But there was no significant correlation between IC types and middle concha pneumatization. Conclusion: Accurate diagnosis of ICP is very important in preventing infraorbital nerve damage in surgical procedures to be performed in the maxillary region. The results of this study could be a guide for surgical planning in this region. Level of evidence: Retrospective study.

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.

Bilateral variations and sexual dimorphism in morphometric parameters of infraorbital groove, canal and foramen in human foetuses / Variaciones bilaterales y dimorfismo sexual en los parámetros morfométricos del surco, canal y foramen infraorbitario en fetos humanos

Foetal anatomy seems to be highly promising developing speciality in the recent past. Maxilla is the key to facial skeleton. Its anatomy in general and bilateral variations along with sexual dimorphism in particular are of great surgical and forensic importance. Thirty two maxillae of sixteen human foetuses (21 wks to 34 wks) were considered to measure lengths of infraorbital groove and canal, widths of ends of infraorbital groove, diameters of infraorbital foramen and the distances of latter from infraorbital margin and nasal notch. Groups I (21-25 wks) and II (26-30 wks) foetuses were crucial for bilateral variations for most of the parameters. Distance between infraorbital foramen and nasal notch showed variations on two sides in maximum foetal groups. Infraorbital canal was found to be larger in groups II and III foetuses in females. Width of the posterior end of infraorbital groove was less in group I, equal in group II and more in group III in males. Sexual dimorphism was noticed in all the groups for the distance of infraorbital foramen from infraorbital margin. Distance of infraorbital foramen from nasal notch did not show sexual dimorphism in most of the groups except group I where value was more in males. Rule of generalized phenomenon of larger skeleton in male was not applicable in most of the groups.

La anatomía fetal, con su desarrollo en los últimos años, parece ser especialidad muy prometedora. El maxilar es la clave del esqueleto facial. Su anatomía en general y las variaciones bilaterales junto al dimorfismo sexual en particular, son de gran importancia quirúrgica y forense. Fueron estudiados 32 maxilares de 16 fetos humanos (21 semanas a 34 semanas) en los cuales se midió la longitud del surco y canal infraorbitario, anchos de los extremos de surco infraorbitario, diámetros del foramen infraorbitario y las distancias de este último desde el margen infraorbitario hasta la escotadura nasal. Las variaciones bilaterales en la mayoría de los parámetros fue en los grupos de fetos I (21-25 semanas) y II (26-30 semanas). La distancia entre el foramen infraorbitario y escotadura nasal mostró variaciones máximas en dos partes en los grupos de fetos. El canal Infraorbitario resultó ser más largo en los grupos II y III de fetos femeninos. El ancho del extremo posterior del surco infraorbitario fue menor en el grupo de fetos masculino I, igual en el grupo II y mayor en el grupo III. El dimorfismo sexual se observó en todos los grupos en la distancia desde el foramen infraorbitario hasta el margen infraorbitario. La distancia desde el foramen infraorbitario hasta la escotadura nasal no mostró dimorfismo sexual en la mayoría de los grupos a excepción del grupo I, donde el valor fue mayor en los hombres. La norma generalizada que el esqueleto más grande es del género masculino no fue aplicable en la mayoría de los grupos.

Morphometric analysis of infraorbital foramen and infraorbital canal in human feotuses / Análisis morfométrico del foramen infraorbitario y canal infraorbitario en fetos humanos

Literature regarding analysis of infraorbital foramen and canal exists in adult but it is scanty in foetuses. Morphometric measurements were performed in sixty maxillae dissected out from thirty human foetuses. The latter were divided into five groups on the basis of age i.e. groups I(<17 weeks IUL),II (17-20 weeks IUL), III (21-25 weeks IUL),IV (26-30 weeks IUL) and V (>30 weeks IUL).Four parameters considered were length of infraorbital foramen and canal and width of anterior and posterior ends of infraorbital foramen. Range of measurements between the smallest fetal group to largest fetal group for length of infraorbital foramen and canal and width at the anterior and posterior ends of infraorbital foramen were 4.01mm to 6.00 mm,0.67 mm to 2.60 mm,0.64 mm to 1.65 mm and 1.39 mm to 3.01 mm, respectively.The shape of the infraorbital foramen is maintained in most of the groups. Correlation coefficient analysis between measurements of lengths and aging foetuses is indicative of variable osteoblastic and osteoclastic activities. Enhanced osteoblastic activity seems to be an important phenomenon in postnatal life.

Existe literatura en relación con el análisis de foramen y canal infraorbitarios en adultos pero es escasa en fetos. Se realizaron mediciones morfométricas en 60 maxilares disecados de 30 fetos humanos. Los fetos fueron divididos en cinco grupos en función de la edad, es decir los grupos I (<17 semana VIU), II (17-20 semanas VIU), III (21-25 semanas VIU), IV (26-30 semanas VIU) y V (> 30 semanas VIU). Fueron considerados cuatro parámetros : longitudes del foramen y canal infraorbitario y anchos anterior y posterior de los extremos del foramen infraorbitario. El rango de las mediciones entre el grupo de fetos más pequeño al grupo más grande tanto de las longitudes del foramen y canal infraorbitario como los anchos de los extremos en la parte anterior y posterior del foramen infraorbitario fueron: 4.01mm a 6.00 mm, 0.67 mm a 2.60 mm, 0.64 mm a 1.65 mm y 1.39 mm a 3.01 mm, respectivamente. La forma del foramen infraorbitario se mantuvo en la mayoría de los grupos. El análisis del coeficiente de correlación entre las mediciones de longitudes y edades de los fetos, es indicativo de las variables de actividades osteoblástica y osteoclástica. El aumento de la actividad osteoblástica parece ser un fenómeno importante en la vida postnatal.

Anatomical Observation and Clinical Significance of Suborbital Foramen and Infraorbital Canal / 昆明医科大学学报

In this article, 100 maxilla samples of the Kunming area werc takcn for observing the suborbital foramen and infraorbital canal and their relative data. The purpose of this investigation was to provide an anatomical basis for the clinical block anesthesia of the infraorbital nerve and its branches. The results show that 93％ of the suborbital foramen is an oval-shaped mono-foramen and 7％ has a paraforamen, their exact positions on the maxilla being measured. The vertical diameter of the suborbital foramen averages 5.83mm, and the transverse one 3.05ram. The average value of the vertical diameter of the infraorbital canal is 11mm, its anterior part axis toward inferior, anterior and interior. 66% of infraorbital canals can be passed through smoothly by a ~#6 hypodermic needle, 12％ with reistance and 22％ can not be passed through.