Prevalence and laterality of supraorbital ethmoid cell and its relationship with the anterior ethmoid artery among patients who underwent paranasal sinus computed tomography scan at Muhimbili national hospital.

Abstract

ABSTRACT Background: The anterior ethmoid artery (AEA) plays an important role in functional endoscopic surgery (FESS) as one of the surgical landmarks, it’s a branch of the ophthalmic artery. The position of the anterior ethmoid artery in relation to the ethmoid roof is very variable as it courses through the ethmoid labyrinth, it can be altered by the presence of supraorbital ethmoid cell, thus, the artery becomes vulnerable to iatrogenic injuries and very serious complications such as severe bleeding. To prevent iatrogenic injury to the base of skull, a surgeon's knowledge of the anatomy of the ethmoid sinuses and orbital plate of the frontal bone is of utmost importance during opening into the sinuses. The possibility of iatrogenic injury during functional endoscopic sinus surgery exists due to presence of supraorbital ethmoid cell pneumatization, which may change the position of the anterior ethmoid artery as it courses within the ethmoid cavity. Objective: To determine the prevalence and laterality of supraorbital ethmoid cell and its relationship with the anterior ethmoid artery among patients who underwent paranasal sinus computed tomographic scan at Muhimbili National Hospital in Tanzania. Material and methods: A cross-sectional retrospective hospital-based study was conducted at Muhimbili National Hospital, radiology department, for a duration of six months, from December 2023 to May 2024, and included 316 paranasal sinus computed tomographic scans of patients aged 12 years and older. A convenience sampling method was employed, whereby data collection was done from all paranasal sinus computed tomographic scans that met criteria from 1st of January 2020 to 31st of December 2022. Data collection checklists were used to record the age, sex, presence, and laterality of supraorbital ethmoid cell, as well as the position of the anterior ethmoid artery about the base of the skull. Results: A total of 316 paranasal sinus computed tomographic scans were included in this study, of whom 139 (44.0%) were males and 177 (56.0%) were females, with a female-to male ratio of 1:3.1. The paranasal sinus computed tomographic scans studied were from patients aged 12 to 90 years, with a median age of 40 (28,53). The most common age groups were 32–51 years and 12-31 years (40.8% and 32.9%, respectively). The prevalence of supraorbital ethmoid cells was found to be 61 (19.3%). Supraorbital ethmoid cells were more vi common in males as compared to females by 25.2% and 14.7%, respectively. Among the 61 paranasal sinus computed tomographic scan images, 68.9% were found to have bilateral supraorbital ethmoid cells, while 21.3% and 9.8% were found unilateral on the right and left sides, respectively. Males accounted for bilateral supraorbital ethmoid cells by 74.2%. The anterior ethmoid artery was found to be Group II by 45.6%, followed by Group I and Group III by 31.1% and 23.3%, respectively. The majority of the computed tomographic scans in Groups II and III were males, at 53.3% and 28.3%, respectively. Contrary to Group I, in which 48.8% were females. Conclusion: The prevalence of supraorbital ethmoid cell was found to be 19.3%, with a high proportion of bilateral distribution of 68.9%. A large percentage of Group II anterior ethmoid arteries was found to be related to supraorbital ethmoid cell by 45.6%. The position of the anterior ethmoid artery in the ethmoid labyrinthine varies between the two sides of the same patient depending on the laterality of the supraorbital ethmoid cell, so this variation is very crucial to be known by a surgeon before and during endoscopic sinus surgery. Recommendations: Owing to a significant supraorbital ethmoid cell’s prevalence among the population, Clinicians should be aware to include preoperative evaluation of the PNS CT scan for the presence and laterality of supraorbital ethmoid cell and the position of the anterior ethmoid artery in patients undergoing endoscopic sinus surgery so as to minimize iatrogenic injuries and complication. Radiologists should also be aware that PNS CT scans with supraorbital ethmoid cell have to be reported. More emphasis on the use of preoperative paranasal sinus computed tomographic scans in the management guidelines of patients requiring endoscopic sinus surgery. Due to Tanzania's data shortage, additional research at various health institutes throughout the nation is advised.