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Published on: October 6, 2022
Redefining Sciatic Nerve Division Patterns: Cadaveric Study Introducing a Novel Index-Based Classification for
Vandana Tiwari1, Priti Chaudhary2, Navita Aggarwal3
1Associate Professor, Department of Anatomy, All India Institute of Medical Sciences, Bathinda, Punjab, India.
Background:
Increasing anatomical studies reveal considerable variability in sciatic nerve (SN) division, posing challenges in orthopaedic, neurosurgical and anaesthetic procedures. To address limitations in current classification models, this study introduces a novel sciatic nerve division index (SNDI) for precise sub-classification of SN bifurcation levels.
Methods:
Fifty-eight lower limbs from 29 formalin-fixed adult cadavers were dissected to trace SN bifurcation beyond the lower border of piriformis (Beaton and Anson Type A). These were further subtyped as Type AI (proximal), AII (mid-thigh) and AIII (distal) based on the vertical bifurcation level using SNDI-a reproducible morphometric tool.
Results:
Among the 58 limbs, 42 (72.41%) showed extra-pelvic (Type A) bifurcation. Of these, mid-thigh (Type AII) was most common (44.8%), followed by proximal (Type AI) in 29.3% and distal (Type AIII) in 25.9%. Non-Type A variants constituted 27.58%. Although more variations were seen in males, differences between male and female and left and right sides of the same cadaver were statistically insignificant.
Conclusion:
This study underscores the high variability in SN division and the inadequacy of conventional models. The SNDI system improved consistency and anatomical localization of extra pelvic bifurcation of SN, improving procedural safety and guiding future research and education.
