Variations of nervus ischiadicus and their clinical importance: A cadaveric and MRI study

Nervus Ischiadicus Variations and Clinical Significance: Cadaver and MRI Study Aim: When size and function of NI considered, disabilities caused by entrapment or injuries can be better understood. We assessed NI variations may lead to DGS and increase the risk of nerve injuries during surgical and medical applications, NI the morphometric and topographic characteristics. Material and methods: In 18 cadaver extremities NI variations related to NI-MP, bifurcation levels, morphometric and topographic features were investigated. For NI morphometric and topographic features, NI width at the FI, NIT and NIB levels, the distances from FI to TM, SIAS, CI, SIPS, HS and TI, the distances between TI -TM and from NI to TI and TM were measured NI variations were investigated in 115 hip MRIs from the radiology digital archive. Results: In all specimens Type A variations and NI bifurcation levels at upper corner of fossa poplitea (Group E) were observed. NI width were milimetrically measured as 16.61 ± 1.91 at NIF, NIT: 11.44 ± 2.74, NIB: 8.05 ± 1.76 respectively. Other measurements were as follow: FI-TM: 71 ± 9.62, FI-SIAS: 129.1 ± 9.1, FI-CI: 134.6 ± 6.33, FI-SIPS: 80.77 ± 10.40, FI-HS: 78.16 ± 10.54, FI-TI: 55.11 ± 5.56, NI-TI: 20.22 ± 3.65, NI-TM: 49.38 ± 10.27, TI-TM: 81.05 ± 12.19. In 5 hip MRIs Type B (4.3 %) and in 110 hip MRIs Type A (95.6 %) were observed. Conclusion: Our cadaver and MRI studies may be a guide for clinical applications and contribute to decrease nerve injury problems. Furthermore, we observed variations can be shown on routine hip MRIs. Keywords; Nervus ischiadicus, variations, piriformis syndrome, cadaver, magnetic resonance imaging