LAUSR

INTRODUCTION Reports of a duplicated or fenestrated inferior petrosal sinus are scarce or not found in the literature, respectively. Moreover, to our knowledge, cadaveric reports of the latter previously have not been reported. Therefore, the current cadaveric study was performed. METHODS Twenty adult cadaveric heads (40 sides) were used for this study. Following removal of the brain the inferior petrosal sinus was dissected using a surgical microscope. Specimens with duplication or fenestration of the inferior petrosal sinus anywhere along its course were photographed and measured. RESULTS On two (5%) left sides, a fenestration was identified in the inferior petrosal sinus. One of these was found to have two fenestrations. The mean length and width of the three fenestrations were 2.3mm and 0.95mm, respectively. The three fenestrations were located at the middle to terminal parts of the IPS. On two (5%) left sides and one (2.5%) right side, the inferior petrosal sinus was duplicated over a part of its course. The mean length and width of the duplicated parts of the inferior petrosal sinus were 25.9mm and 3.1mm, respectively. No statistical significance was found for fenestrations/duplications comparing males versus females but fenestrations were statistically significant (p<0.05) for occurring on left sides. CONCLUSIONS Unfamiliarity with duplicated/fenestrated IPS could increase the risk of iatrogenic injury and misinterpretation of imaging. Further radiological imaging studies are required to substantiate the mechanisms by which duplicated/fenestrated IPS affects clinical outcomes more accurately. Nonetheless, anatomical awareness of such lesser-known variations of the IPS is crucial for promoting safe and effective interventional approaches at the skull base.