Anatomical variations of the superior cerebellar artery: A cadaveric study at the University Teaching Hospitals, Lusaka, Zambia

The superior cerebellar artery usually arises from the terminal end of the basilar artery. It may also originate from the posterior cerebral artery and or from a common trunk with the posterior cerebral artery. The anatomical variations of superior cerebellar artery show ethnic differences, but there are few reports on African populations in particular none from Zambia. Variations of the superior cerebellar artery might cause compression symptoms of cranial nerves III, IV and V. Furthermore, the presence of such variations has been considered to be a factor in the aetiology of  aneurysms and thrombus formation leading to cerebellar infarcts. The objectives of the study were to explore anatomical variations on the origin of the superior cerebellar artery; to measure the outer diameter at its origin and the length of superior cerebellar artery to its first bifurcation; to establish the presence of duplication , triplication , hypoplasia , agenesis , fenestration and any other anomalies that were detectable. This was a descriptive cross-sectional study in which 46 post-mortem human cadaveric brains were systematically sampled. A total of 113 superior cerebellar arteries were identified in 42 male and four female cadavers of age ranging between 18 and 65 years (mean 34.05±9.237mm). Superior cerebellar artery arose from the basilar artery as a single vessel in 49.5%, the common trunk arose in 6.2% and posterior cerebral artery origin was seen in 5.7%. Overall duplication of the superior cerebellar artery was seen in 35.5% and triplication in 5.3%. Nineteen (16.8%) of the superior cerebellar arteries were hypoplastic (less than 1mm) and ninety-four (83.2%) were normal. The diameter of the superior cerebellar artery at its origin ranged 0.25mm to 2.48mm (mean 1.42±0.54mm). The length of the superior cerebellar artery to its first bifurcation ranged from 3.77mm to 33.53mm (mean 21.92±7.40mm). Statistically, gender had no significant association of superior cerebellar artery variations (p>0.05). This knowledge will improvediagnosis and management of patients with vascular disorders of the posterior circulation. The newly identified patterns could be a contribution to the SCA classification system. Key words: Superior cerebellar artery, duplication, triplication and hypoplasia