2D and 3D microstructural analysis of the iliotibial tract

Area of Science:

• Anatomy and Histology
• Biomechanics
• Medical Imaging

Background:

• The fascial system's role in musculoskeletal connections is recognized, but its microstructural topography and clinical implications remain unclear.
• The iliotibial tract (ITT) is crucial in iliotibial band syndrome, necessitating a detailed understanding of its structure.

Purpose of the Study:

• To characterize the microstructural properties of the iliotibial tract (ITT) based on its topography.
• To investigate layer thickness, fibre orientation, and tortuosity using 2D histology and cryo-CECT.
• To provide quantitative data for clinical applications in reconstructive surgery and physiotherapy.

Main Methods:

• Utilized classical 2D histology and cryogenic contrast-enhanced microcomputed tomography (cryo-CECT) for microstructural analysis.
• Examined total thickness, number of layers, layer thickness, fibre orientation, and fibre tortuosity across different ITT regions.
• Employed 3D imaging from cryo-CECT to confirm histological findings and assess fibre characteristics.

Main Results:

• The ITT exhibited regional variations in thickness, with the inferior posterior region being the thickest.
• The ITT comprised 1-3 layers, with the intermediate layer being the thickest and posterior regions often having more layers.
• Fibre orientation differed by layer (intermediate: oblique longitudinal; superficial/deep: transversal), and fibre tortuosity correlated with orientation.

Conclusions:

• The study quantitatively details the microstructural heterogeneity of the ITT, highlighting regional differences.
• Cryo-CECT is a valuable tool for precise 3D assessment of fibre orientation and tortuosity in fascial tissues.
• These findings enhance understanding of ITT structure, benefiting clinical practices like reconstructive surgery and physiotherapy.