Cytomorphological Effects of Lightweight and Heavyweight Polypropylene Mesh on the Ilioinguinal Nerve: An Experimental Study.

Objective This study aimed to investigate the cytomorphological effects of heavyweight and lightweight mesh on the ilioinguinal nerve in an experimental animal model. Methods Sixteen New Zealand male rabbits were included in the study. The left inguinal regions of the first six animals were assigned as controls and the right inguinal regions were assigned as the sham group. The left inguinal regions of the remaining 10 animals were assigned as the lightweight mesh group and the right inguinal regions were assigned as the heavyweight mesh group. No intervention was performed in the control group. In the sham group, only ilioinguinal nerve exploration was performed. In mesh groups, ilioinguinal nerve exploration was performed and the mesh was implanted on the ilioinguinal nerve. After three months, ilioinguinal nerve specimens were excised from both sides for cytomorphological examination. Results Myelin sheath thickening, separation of the myelin layers, and myelin vacuolization were more pronounced in the heavyweight mesh group compared to the lightweight mesh group. The G-ratio was moderately increased in the heavyweight mesh group when compared to other groups. The ratio of fibers with ≤4 µm diameter was higher in the lightweight mesh group compared to other groups, and the ratio of fibers with ≥9 µm diameter was higher in the heavyweight mesh group than in the other groups (p<0.05). Conclusion Both of the meshes induce cytomorphological alterations on the adjacent nerve tissues caused by foreign body reaction and compression. Ilioinguinal nerve degeneration was more pronounced in the heavyweight mesh than in the lightweight mesh. Histological alterations on the ilioinguinal nerves caused by different meshes may be related to chronic pain after hernia surgery. We believe our study will serve as a guide for future studies on the topic.