Virginia Research Day 2022

Medical Student Research Biomedical

12 Obturator Nerve Macroanalysis And Link Between Non-Neural Tissue Within The Nerve In Association With Ses And Laterality

Mason Yount; Alekhya Peruri; Alexandra Morgan; Jonathan Millard; Kelly Roballo Corresponding author: myount@vt.vcom.edu

Edward Via College of Osteopathic Medicine, Blacksburg, VA

Background: Nerve morphology and its role in the regeneration process following peripheral nerve injury and repair has been an active area of research for decades. Through this research there has been competing theories proposed about the fascicular organization in peripheral nerves, with theories of linear running “cable-like structures” versus a more intertwined “plexiform structure” or some combination of the two. A more comprehensive understanding of nerve morphology and its effects on nerve transplants has the capability to improve clinical outcomes. Currently, nerve replacements are often conducted utilizing a donor nerve or nerve conduit, increasing the risk of unmatchable donor-recipient grafting leading to poor functional recovery. We performed morphologic analysis of obturator nerve (ON) cross sections to assist in coming up with a method to be able to compare nerve morphology, considering donor and recipient traits with the goal to provide the best matched nerve after injury increasing the likelihood of functional recovery. We obtained ON for our analysis, a nerve arising from the lumbar plexus which provides motor and sensory innervation to portions of the medial thigh. In

our analysis we compared the quantity of non- neural tissue to nerve tissue contained within the epineurium and differences in this quantity between male and female sex, as well as right versus left. The quantity of non-neural tissue was assessed to look for differences that may help to improve nerve matching for transplant procedures in the future. Methods: Right and left ON were isolated from 25 formalin-fixed whole-body donors for analysis. Macroscopy images of nerve cross sections were taken using a 20X magnification microscope. Fascicle surface area and percentage of non-neural tissue were quantified using ImageJ software. Comparisons were made between right and left sided nerves and donor sex via independent group T-test. Results: Analysis of the non-neural tissue compared to the neural tissue housed within the epineurium revealed differences in the percentage of the non-neural tissue present in both left versus right and male versus female. Overall, the quantity of non-neural tissue made up on average 32.667% of the female ON and 35.717% of the male ON, with a statistically significant p value of 0.0696. This

was a difference of 3.05% more non-neural tissue in male ON. The ON of females contained 0.644% more non-neural tissue on the left than on the right. Male ON contained 1.397% more non-neural tissue on the right than on the left. Overall average, excluding sex, right ON contained 0.121% more non-neural tissue, which was not statistically significant. Upon comparison of the ratio of the percentage of non-neural tissue to the surface area of the nerves, females were found to have 5.099%/ mm 2 more non-neural tissue than males in their left obturator nerve and 4.874%/mm2 more in their right obturator nerves. Conclusion: The varying amounts of non- neural tissue observed demonstrates that there are differences among nerve morphology between sexes, indicating that this is a parameter that should be considered when identifying suitable donor-recipient nerve matches with the goal of improving clinical outcomes. Further analysis can be done on individual patient characteristics, to be able to predict nerve morphology.

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