Age-dependent changes in the transverse carpal ligament and median nerve: a cadaveric histological and biomechanical study.

TCL dynamic stiffness increased with advancing age across all measured regions.

• Fifty formalin-embalmed cadavers aged 40-93 years were studied, yielding 100 TCL specimens.
• A digital palpation device (MyotonPRO) was used to measure TCL dynamic stiffness in situ at proximal, middle, and distal regions.
• Pearson's correlation was used to determine associations between TCL mechanical properties and age.
• Age-dependent increase in TCL stiffness was observed across the studied age range.

TCL elasticity, mechanical stress relaxation time, and creep all decreased with advancing age.

• Elasticity was measured as logarithmic decrement using the MyotonPRO device.
• Decreased elasticity, relaxation time, and creep were observed with increasing age.
• Measurements were taken at proximal, middle, and distal regions of the TCL.
• These changes indicate the TCL becomes less viscoelastic and more rigid with aging.

Histological analyses of the TCL revealed reduced fibroblast density and disorganized collagen fibers with advancing age.

• Masson's trichrome staining and scanning electron microscopy were used to assess collagen fiber organization and fibroblast density.
• Older specimens showed disorganized collagen fibers with large clefts between bundles.
• An increased fine collagen meshwork in the interfascicular matrix was observed in older specimens.
• Reduced fibroblast density was noted with advancing age.

Degenerative changes in the median nerve were observed with advancing age, including thinning of connective tissue layers and diminished myelin sheaths.

• Median nerves were excised after mechanical testing and assessed histologically.
• Thinning of connective tissue layers surrounding the median nerve was noted with advancing age.
• Diminished myelin sheaths were observed in older specimens.
• Masson's trichrome staining was used to assess nerve structure.

The study used formalin-embalmed cadavers spanning a wide age range to investigate age-related changes in the TCL and median nerve.

• Fifty cadavers aged 40 to 93 years were included.
• One hundred TCL specimens in total were analyzed.
• Both mechanical testing (MyotonPRO) and histological methods (Masson's trichrome staining and scanning electron microscopy) were employed.
• Formalin embalming was the preservation method used, which may influence tissue mechanical properties.

Age-related structural and mechanical alterations in the TCL and median nerve may predispose elderly individuals to a higher risk of carpal tunnel syndrome.

• Increased TCL stiffness combined with structural disorganization was observed in older specimens.
• Degenerative changes in the median nerve, including thinning connective tissue layers and diminished myelin sheaths, were concurrent findings.
• The authors concluded these changes 'may predispose elderly individuals to a higher risk of carpal tunnel syndrome.'
• The findings underscore 'the need for targeted preventive and therapeutic strategies' according to the authors.