Infraorbital canal variants and its clinical and surgical implications. A systematic review.

BACKGROUND: Recent literature highlights anomalous cranial nerves in the sinonasal region, notably in the sphenoid and maxillary sinuses, linked to anatomical factors. However, data on the suspended infraorbital canal (IOC) variant is scarce in cross-sectional imaging. Anatomical variations in the sphenoid sinuses, including optic, maxillary, and vidian nerves, raise interest among specialists involved in advanced sinonasal procedures. The infraorbital nerve's (ION) course along the orbital floor and its abnormal positioning within the orbital and maxillary sinus region pose risks of iatrogenic complications. A comprehensive radiological assessment is crucial before sinonasal surgeries. Cone-beam computed tomography (CBCT) is preferred for its spatial resolution and reduced radiation exposure. OBJECTIVE: The aim of this study was to describe the prevalence of anatomical variants of the infraorbital canal (IOC) and report its association with clinical condition or surgical implication. METHODS: We searched Medline, Scopus, Web of Science, Google Scholar, CINAHL, and LILACS databases from their inception up to June 2023. Two authors independently performed the search, study selection, data extraction, and assessed the methodological quality with assurance tool for anatomical studies (AQUA). Finally, the pooled prevalence was estimated using a random effects model. RESULTS: Preliminary results show that three types are prevalent, type 1: the IOC does not bulge into the maxillary sinus (MS); therefore, the infraorbital foramen through the anterior wall of MS could be used for identification of the ION. Type 2: the IOC divided the orbital floor into medial and lateral aspects. Type 3: the IOC hangs in the MS and the entire orbital floor lying above the IOC. From which the clinical implications where mainly surgical, in type 1 the infraorbital foramen through the anterior wall of MS could be used for identification of the ION, while in type 2, since the lateral orbital floor could not be directly accessed an inferiorly transposition of ION is helpful to expose the lateral orbital wall directly with a 0 scope; or using angled endoscopes and instruments, however, the authors opinion is that direct exposure potentially facilitates the visualization and management in complex situations such as residual or recurrent mass, foreign body, and fracture located at the lateral aspect of the canal. Lastly, in type 3, the ION it's easily exposed with a 0° scope. CONCLUSIONS: This systematic review identified four IOC variants: Type 1, within or below the MS roof; Type 2, partially protruding into the sinus; Type 3, fully protruding into the sinus or suspended from the roof; and Type 4, in the orbital floor. Clinical recommendations aim to prevent nerve injuries and enhance preoperative assessments. However, the lack of consistent statistical methods limits robust associations between IOC variants and clinical outcomes. Data heterogeneity and the absence of standardized reporting impede meta-analysis. Future research should prioritize detailed reporting, objective measurements, and statistical approaches for a comprehensive understanding of IOC variants and their clinical implications. Open Science Framework (OSF): https://doi.org/10.17605/OSF.IO/UGYFZ .

Frequency, location, and diameter of the anastomosis between the posterior superior alveolar artery and the infraorbital artery in imaging studies: systematic review and meta-analysis.

The anastomosis between the posterior superior alveolar artery (PSAA) and the infraorbital artery (IOA) courses along half of the lateral wall of the maxillary sinus. Risk of injury to the anastomosis between PSAA and IOA during surgical procedures has been reported. The aim of the present study was to carry out a systematic review and meta-analysis to determine the frequency, location, and diameter of the anastomosis between PSAA and IOA in imaging studies (cone-beam computed tomography, spiral cone-beam computed tomography, and computed tomography). A search was carried out in the PubMed, EMBASE, and LILACS. Original works were included reporting imaging studies to analyze the frequency, location, and diameter of the anastomosis in humans. The risks of bias were analyzed using the AQUA tool. Generalized linear mixed models were used to estimate the frequency and the 95% CI in the meta-analysis. The variance in prevalence estimates was stabilized by logit transformation. The qualitative analysis included 49 studies with 10,837 patients. The frequency of the anastomosis between PSAA and IOA was 74% (prediction interval 0.20-0.97%). The anastomosis was most frequently located in the intraosseous region (60.0%), followed by the submembranous region (33.0%), and least frequently in an extraosseous location (5.0%). Arteries with diameter of 1.0-1.9 mm were most frequent (32.0%), followed by arteries with diameter less than 1 mm (23.0%); a small number with diameter greater than 2 mm was recorded (4.0%). These data can be used as a reference to help surgeons when planning interventions in the lateral wall of the maxillary sinus. Registration number: INPLASY, number 202120071.

Analysis of the presence, location and morphometry of the «alveolar antral artery¼ by cone-beam computed tomography in Chilean adults / Análisis de la presencia, ubicación y morfometría de la arteria alvéolo-antral por tomografía computarizada de haz cónico en adultos chilenos

SUMMARY: The posterior superior alveolar artery is responsible for the vascularisation of the mucous which covers the posterior wall of the maxillary sinus, pulp and the periodontal tissues of upper molars. The collateral rami of the infraorbital artery irrigate the mucous of the anterior and lateral walls of the maxillary sinus, as well as the pulp and periodontal tissue of the upper anterior teeth and upper premolars. Both these arteries present intraosseous and extraosseous rami which form an anastomosis in the anterior and lateral walls of the maxillary sinus, called the alveolar antral artery (AAA). The aim of this study was to analyse the presence, location and morphometry of the AAA in a Chilean population, considering sex, side and age, using Cone-Beam computed tomography (CBCT). Forty-two CBCT examinations of Chilean adults were evaluated to analyse the presence, location (extraosseous, intraosseous or subperiosteal) and diameter (<1mm, 1-2 mm, 2-3 mm, >3 mm) of the AAA and the distance from the AAA to the amelocemental limit of the upper second premolar (2PM), permanent upper first molar (1M) and permanent upper second molar (2M) by sex and age range. Pearson's chi-squared test, Student's t-test, ANOVA and Pearson's correlation coefficient were applied, using a significance threshold of 5 %. AAA was found in 75 sides (89.3 %), 38 on the right side (90.5 %) and 37 on the left (88.09 %); extraosseous location was most common. More than 80 % of the arteries presented a diameter between 1 and 2 mm, with no important differences between sexes or age ranges. In younger individuals, the artery was located closer to the vestibular amelocemental limit than in older individuals. Carrying out a proper treatment plan which includes imagenological analysis before surgical procedures is essential to avoid possible haemorrhagic events in the region.

RESUMEN: Arteria alveolar superior posterior es responsable de la vascularización de la mucosa que recubre la pared posterior del seno maxilar, la pulpa y el tejido peridontal en el que se insertan los molares superiores. Las ramas colaterales de la arteria infraorbitaria irrigan la mucosa de las paredes anterior y lateral del seno maxilar, así como la pulpa y el periodonto de los dientes anteriores superiores y los premolares superiores. Ambas arterias presentan ramas intraóseas y extraóseas que forman una anastomosis en las paredes anterior y lateral del seno maxilar, denominada arteria alvéolo antral (AAA). El objetivo de este estudio fue analizar la presencia, localización y morfometría del AAA en una población chilena, considerando sexo, lado y edad, mediante tomografía computarizada Cone-Beam (CBCT). Se evaluaron 42 exámenes CBCT de adultos chilenos para analizar la presencia, ubicación (extraósea, intraósea o subperióstica) y diámetro (<1 mm, 1-2 mm, 2-3 mm,> 3 mm) del AAA. y la distancia del AAA al límite amelocemental del segundo premolar superior (2PM), primer molar superior permanente (1M) y segundo molar superior permanente (2M) por sexo y rango de edad. Se aplicaron la prueba de chi-cuadrado de Pearson, la prueba t de Student, ANOVA y el coeficiente de correlación de Pearson, utilizando un umbral de significancia del 5 %. Se encontró AAA en 75 lados (89,3 %), 38 del lado derecho (90,5 %) y 37 del lado izquierdo (88,09 %); la localización extraósea fue la más común. Más del 80 % de las arterias presentaban un diámetro entre 1 y 2 mm, sin diferencias importantes entre sexos ni rangos de edad. En individuos más jóvenes, la arteria se ubicó más cerca del límite amelocemental vestibular que en individuos mayores. La realización de un adecuado plan de tratamiento que incluya análisis imagenológico antes de los procedimientos quirúrgicos es fundamental para evitar posibles eventos hemorrágicos en la región.

Evaluación de la arteria alveolo-antral mediante tomografía volumétrica en población mexicana y su relación con levantamiento del piso del seno maxilar / CBCT evaluation of the alveolar antral artery in a mexican cohort and its relationship to maxillary sinus floor lifting

Introducción: El conocimiento de la anatomía de la región maxilar debe ser esencial para el cirujano antes de realizar levantamiento del seno maxilar para evitar complicaciones. La arteria alveolo antral forma una anastomosis intraósea con la arteria infraorbitaria a nivel de la pared antero lateral del seno maxilar, aproximadamente a una distancia de entre 18.9 y 19.6 mm desde el reborde alveolar maxilar. La arteria alveolo antral es la encargada de dar vascularidad a la membrana mucosa del seno maxilar, pared antero lateral del seno y tejido perióstico subyacente.Objetivo: Describir y establecer la frecuencia, diámetro y localización dela anastomosis entre la arteria infraorbitaria y la arteria alveolar posterior superior, llamada arteria alveolo antral y su relación con la cresta ósea alveolar en una población mexicana. Material y métodos: Se realizaun protocolo de estudio observacional, descriptivo y transversal en una población de 1,116 pacientes derecho habientes del Instituto de Seguridad Social y Servicios para los Trabajadores del Estado (ISSSTE), en el oriente de la Ciudad de México, mediante la revisión de estudios de tomografía volumétrica computarizada. Resultados: Se encuentra la anastomosis arterial en el 90 por ciento de los estudios revisados, correspondiente a 1,005 estudios de tomografía.

Introduction: In order to avoid complications, it is essential for surgeonsto have a detailed knowledge of the anatomy of the superior maxillarybone prior to performing any sinus lift procedure. The alveolarantral artery forms an intraosseous anastomosis with the infraorbitalartery at the level of the anterolateral wall of the maxillary antrum at anapproximate distance of between 18.9 and 19.6 mm from the maxillaryalveolar ridge. The alveolar antral artery is responsible for providingvascularity to the mucous membrane of the maxillary sinus, the anteriorlateral wall of the sinus, and the underlying periosteal tissue. Objective:To analyze and establish the frequency, diameter, and locationof the anastomosis between the infraorbital artery and the posteriorsuperior alveolar artery known as the alveolar antral artery, and itsrelationship to the alveolar bone crest in a Mexican cohort. Materialand methods. We conducted a cross-sectional observational descriptivestudy involving a cohort comprised of 1,116 patients of the Institute forSocial Security and Services for State Workers (ISSSTE) on the eastside of Mexico City. The study consisted of a review of CBCT studies.Results: The arterial anastomosis was found in 90% of the 1,005 CBCTstudies reviewed, based on which the following values were determinedfor the distance between the alveolar ridge and the canal of the alveolarantral artery: for the fi rst premolar, 18.24 mm; second premolar,17.35 mm; fi rst molar, 16.96 mm, and for the second molar, 18.75 mm.Conclusions: We established the average measurements for the locationof the vascular bundle in question and the measurements neededto safeguard it along its course, which is important for the preservationand osseointegration of bone grafts placed during maxillary sinus liftprocedures, thus providing a margin of safety not previously reportedin the literature for a Mexican cohort.