Morphological Changes of Collagen Fibrils in the Subsynovial Connective Tissue in Patients with Carpal Tunnel Syndrome

Principal Investigator: Peter C. Amadio, M.D.
Project Coordinator: Chunfeng Zhao, M.D. —

The subsynovial connective tissue in the carpal tunnel is highly specialized for tendon gliding and tendon nutrition. Commonly encountered pathologic findings in the subsynovial connective tissue of carpal tunnel syndrome are proliferation with thickening of tendon sheath, fibrosis, and vascular lesions including thickening of vessel walls, intimal hyperplasia, vascular proliferation, and thrombosis. In general, fibrotic changes closely correlate with overproduction and structural changes of collagen. In this study, the morphological changes of the collagen fibrils in the subsynovial connective tissue of patients with idiopathic carpal tunnel syndrome were analyzed using transmission electron microscopy and compared to cadaver controls. The collagen fibril diameter was significantly larger in the patients with CTS and their density was smaller compared to the normal control. Future studies are necessary to determine the relationship between the morphological and mechanical changes, and also the possibility of altering collagen type in the CTS patient.

These findings suggest that in patients with CTS the fibrosis of the SSCT has altered the gliding characteristics of the tendons, which may affect their ability to effectively and efficiently transmit load to the fingers, or to glide independently from each other, or from the nearby median nerve.