Anatomical variations between sciatic nerve and piriformis muscle on computed tomography images from radiotherapy patients

Background: The sciatic nerve has several topographic variations, some of them in relation to the piriformis muscle. Such variations provide meaning insight while addressing pathologies related to sciatic nerve. Hence, this study was undertaken to check the anatomical variations of sciatic nerve using computed tomography (CT) images. Methodology: Thirty-three CT image series from pelvic radiotherapy patients were reviewed, with a DICOM viewer to assess the relation between the sciatic nerve and piriformis muscles, according to Beaton and Aston's classification. Results: Thirty-three CT image sets and 66 gluteal regions were assessed. Type A of Beaton and Aston was found in 84.85% of the samples and Type B was found in 15.15%. No other types were found. Sixty-six percentage of the Type B classifications were bilateral. Conclusion: There is a 15.15% of topographical variation of sciatic nerve consistent with other studies. The use of medical images for this kind of study will allow more reliable results.