Background: Pathologic changes occur commonly in the subsynovial
connective tissue in patients with carpal tunnel syndrome. The purposes of
this study were to investigate the ultrastructural changes of the subsynovial
connective tissue in these patients and compare them with the findings in
cadaver controls.
Methods: The diameter and density of collagen fibrils were measured
by transmission electron microscopy in specimens of subsynovial connective
tissue from ten patients with idiopathic carpal tunnel syndrome and from ten
fresh-frozen cadavers of individuals without known symptoms of carpal tunnel
syndrome.
Results: We noted deformed collagen fibrils with a spiraled
appearance in the specimens from the patients. We also observed phagocytosis
of elastin fibrils in all of those specimens. These changes were noted only
rarely in the cadaver controls. The mean diameter (and standard deviation) of
the collagen fibrils was 45.5 ± 8.0 nm in the control group and 54.8
± 15.2 nm in the patient group (p < 0.05). The mean number of
collagen fibrils per 0.04 µm2 (density) was 201.38 ±
48.88 in the control group and 157.08 ± 54.38 in the patient group (p
< 0.05).
Conclusions: These ultrastructural findings suggest that subsynovial
collagen in patients with carpal tunnel syndrome is structurally different
from that in individuals without carpal tunnel syndrome, but the processes
resulting in that abnormal morphology remain to be elucidated.
Level of Evidence: Prognostic Level III. See Instructions
to Authors for a complete description of levels of evidence.