Comparison of the histological structure of the tibial nerve and its terminal branches in the fresh and fresh-frozen cadavers

Abstract

Background: The aim of this study was to compare the histological structure (cross-sectional area (CSA) and number of nerve fascicles) of the distal part of the tibial nerve (TN) and its terminal branches (medial plantar nerve [MPN], lateral plantar nerve [LPN]) in the fresh and fresh-frozen cadavers using computer assisted image analysis. Materials and methods: The tibial nerve with terminal branches (medial and lateral plantar nerves) were dissected from the fresh and fresh-frozen cadavers. Each nerve was harvested 5 mm proximally and respectively 5 mm distally from the tibial nerve bifurcation, marked, dehydrated, embedded in paraffin, sectioned at 2 µm slices and stained with haematoxylin and eosin. Then the specimens were photographed and analyzed using Olympus cellSens software. Results: The fresh cadavers group comprised 60 feet (mean age 68.1 ± 15.2 years). The mean CSA and the number of nerve fascicles were respectively 15.25 ± 4.6 mm 2 , 30.35 ± 8.45 for the tibial nerve, 8.76 ± 1.93 mm 2 , 20.75 ± 7.04 for the medial plantar nerve and 6.54 ± 2.02 mm 2 , 13.40 ± 5.22 for the lateral plantar nerve. The fresh-frozen cadavers group comprised 21 feet (mean age 75.1 ± 9.0 years). The mean CSA and the number of nerve fascicles were respectively 13.71 ± 5.66 mm 2 , 28.57 ± 8.00 for the tibial nerve, 7.55 ± 3.25 mm 2 , 18.00 ± 6.72 for the medial plantar nerve and 4.29 ± 1.93 mm 2 , 11.33 ± 1.93 for the lateral plantar nerve. Only lateral plantar nerves showed statistical differences in the CSA and the number of nerve fascicles between examined groups (p = 0.000, p = 0.037 respectively). A positive correlation was found between donors age and tibial nerve CSA in the fresh cadavers group (r = 0.44, p = 0.000). A statistical difference was found between the medial and lateral plantar nerves both in the CSA and the number of nerve fascicles (p < 0.001, p < 0.001 respectively). Conclusions: The CSA and the number of nerve fascicles of the tibial and medial plantar nerves were similar in the fresh and fresh-frozen cadavers whilst different in the lateral plantar nerve. The tibial nerve showed increasing CSA with the advanced age in the fresh cadavers. The medial plantar nerve had larger CSA and more nerve fascicles than the lateral plantar nerve.

Current and potential use of fresh frozen cadaver in surgical training and anatomical education

“…Little difference with Thiel-fixed cadavers Topp et al (2012) of suitability in some tissue types (Warchoł et al, 2021). This comparison on biomechanical suitability is further supported by other studies that measured the stiffness and elasticity of FFC, Thiel's model, and formalin-fixed model where FFC scored the least stiffness (Hohmann et al, 2019).…”

“…The results indicated statistically significant difference of cross‐sectional area only in lateral plantar nerves in both fresh cadavers and FFCs. A difference in the number of nerve fascicle between medial and lateral plantar nerves were noticed only in FFCs (Warchoł et al, 2021). This study also added subjective analysis between cadaveric models.…”

“…Although fresh cadavers are considered the most suitable, owing to the short availability period, they have limitations in terms of wide and long‐term use. The authors recommended the use of FFCs as they are the most flexible and realistic compared to formalin fixated cadavers and Thiel‐embalmed cadavers, as the former makes tissue stiff and the latter has limitations of suitability in some tissue types (Warchoł et al, 2021). This comparison on biomechanical suitability is further supported by other studies that measured the stiffness and elasticity of FFC, Thiel's model, and formalin‐fixed model where FFC scored the least stiffness (Hohmann et al, 2019).…”

“…A more recent study by Warchoł et al (2021) used FFC with computer-assisted technology to compare the histological structure of the distal and terminal branches of the tibial nerve. Thirty fresh cadavers and 21 FFCs were included in the study.…”

“…Thirty fresh cadavers and 21 FFCs were included in the study. Incisions were made between the medial malleolus and the Achilles tendon (Warchoł et al, 2021). Dissection was performed to expose the tibial nerve and the lateral and medial plantar nerves for comparison.…”