Anatomographic Variants of Sphenoid Sinus in Ethiopian Population

Abstract

Neurosurgeons often neglect the sphenoid sinus due to its deep location and difficulties in accessing during surgical interventions. Disease of the sphenoid sinus is difficult to diagnose since its presenting symptoms are difficult to recognize. Moreover, compared with other paranasal sinuses, the sphenoid sinus is considered the most variable air sinus in terms of its degree of pneumatization, number and position of inter-sinus septa, and its relationship with the surrounding anatomical structures. Anatomical variations of the sphenoid sinus are significant from a neurosurgical point of view. Understanding of these variations and its relationships with surrounding structures such as the internal carotid artery, optic nerve, and pituitary gland are clinically relevant to minimize injuries associated with surgical procedures that involve sphenoid sinus. We implemented principles of imaging using computed tomography to elucidate any anatomical variations of the sphenoid sinus in the Ethiopian population. We conducted a prospective study in 200 patients with ages 18–79, who underwent scans of the sphenoid sinus at the Tikur Anbessa Referral Teaching Hospital in 2017–2018. Our findings revealed an incidence of anatomographical variations in terms of pneumatization that varied between 2–50%. These variants include 2% conchal, 25.5% presellar, 50% sellar, and 22.5% postsellar pneumatization. We also demonstrated anatomographic variants in terms of septation, 77.5% single complete septa, 11.5% single incomplete, 10% double septa, and 1% absence of septa. In summary, the sellar pneumatization was found to be the most clinically relevant anatomographic variant among Ethiopians participating in the study, of which 90% were tomographically single septated. These variants must be taken into consideration during trans-sphenoidal surgery and knowledge of the variations has clinical implication in minimizing injuries during invasive surgical procedures involving the sphenoid sinus.

Pneumatization Patterns of the Sphenoid Sinus in Adult Nigerians and Their Clinical Implications

“…Our findings were higher than those reported in Turkey and Iraq and lower than the prevalence in India ( 4 , 13 , 14 ). The frequency of the presellar type, 19.3% was higher than 1.2% reported in a previous Nigerian study by Famurewa et al ( 12 ) According to literature reports, the frequency of the presella type was higher in Ethiopians (25.5%) and lower in Turkish (3.9%), and Indians (9%) ( 3 , 14 , 15 ). The conchal type had a low prevalence (8.3%) although this was higher than some previously documented reports ( 3 , 12 , 15 ).…”

“…The frequency of the presellar type, 19.3% was higher than 1.2% reported in a previous Nigerian study by Famurewa et al ( 12 ) According to literature reports, the frequency of the presella type was higher in Ethiopians (25.5%) and lower in Turkish (3.9%), and Indians (9%) ( 3 , 14 , 15 ). The conchal type had a low prevalence (8.3%) although this was higher than some previously documented reports ( 3 , 12 , 15 ). It was absent in the populations studied by Hiremath et al, Lakshman et al and Abdalla ( 4 , 13 , 16 ) ( Table 2 ).…”

“…The body is aerated forming the sphenoid sinus of varying sizes and shapes among individuals. This sinus is the most inaccessible and most variant paranasal sinus whose pathologies are difficult to diagnose due to its deep location ( 2 , 3 ). The sinus exists at birth as a small mucosal sac of red marrow that evaginated posteriorly from the nasal capsule at the sphenoethmoidal recess during the 3 rd to 4 th month of intrauterine life ( 4 ).…”

“…The sinus exists at birth as a small mucosal sac of red marrow that evaginated posteriorly from the nasal capsule at the sphenoethmoidal recess during the 3 rd to 4 th month of intrauterine life ( 4 ). Pneumatization begins at 3years of age with gradual progression posteriorly and reaches the sellar floor by 7 years ( 3 ). Thereafter, aeration of the sinus proceeds rapidly and reaches its maximum size in adulthood ( 5 ).…”

Anatomical Variation and Clinical Diagnosis

“…Several studies in this Special Issue present new information that has implications for surgical procedures, especially of the head and neck. Degaga and colleagues described variations in the pneumatization and septation of sphenoid sinus diagnosed using computed tomography (CT) scans, which have implications for trans-sphenoidal surgery [ 1 ]. Wang and colleagues evaluated differences in bone parameters at various dental implant sites in the mandible and maxilla [ 2 ].…”