Rules of rhoton and saccular intracranial aneurysms: An in vivo radiological-anatomical confirmatory study in Iraqi population

Abstract

Intracranial aneurysms are a weakened arterial wall due to loss of internal elastic lamina resulting in dilations of the intracranial arteries and these aneurysms are susceptible to rupture, resulting in life-threatening hemorrhage; therefore represents chief cause of hemorrhagic stroke. Rhoton rules are used for the planning the operative approach to these aneurysms. Aim of the study: to evaluate the application of Rhoton rules in our patients with intracranial aneurysms. A retrospective series of 283 aneurysms, from 1st of January 2016 to 1st of December 2018 in Neurosurgical Teaching Hospital Baghdad/Iraq, diagnosed by CT angiography with 3D reconstruction were included in this study to evaluate the age, sex, site, size, locations and application of Rhoton rules in these aneurysms. Of the 283 patients studied, we found 127 aneurysms at the anterior communicating artery (location 1), 80 at the posterior communicating artery (location 2), 37 at the bifurcation of the internal carotid artery (location 3), 21 at the middle cerebral artery (location 4), and 18 in the posterior circulation (location 5). The four rules of Rhoton about intracranial aneurysms: rule one (100%), rule two (84.5%), rule three (84.8%) & rule four (84.8%). The rules of Rhoton is a heterogeneous concept which summarizes several hemodynamic principles and is verified in 80% of aneurysms in Iraqi patients, with different frequencies depending on the rule and location. These findings should be verified in other populations, as our patients are of Hispanic origin in 99.7% of the cases.