Aging of the elastic and collagen fibers in the human cervical interspinous ligaments.
BACKGROUND
The ligaments consist of collagen bands intermingled with elastic fibers that support hundreds of pounds of stress per square inch. In the spine the basic functional unit comprises vertebrae, intervertebral disc and ligament tissues. The interspinous ligaments with the function of limiting the spine flexion are exposed to a traumatic and degenerative process that promotes pain or instability. It has been shown that aging induces structural changes to capsular, fascial and ligamentous structures, mainly to the elastic and collagen fibers. However, the relative changes with age in elastic and collagen fibers have not been quantified.


OBJECTIVE
Examine the changes in the arrangement and amount of the elastic and collagen fibers of the human cervical interspinous ligament and attempt to correlate them with age.


METHODS
Histomorphometric analysis of ligament samples harvested during surgery.


METHODS
We studied the dorsal portion of this ligament from 17 patients aged 16 to 69 years.


METHODS
Fraction of collagen and elastic fibers with linear regression analysis correlating fraction versus age.


METHODS
The elastic and collagen fibers were identified by selective staining methods, and a blinded investigator using an image analysis system performed the histomorphometry.


RESULTS
There is an age-related progressive increase in collagen and mature and elaunin elastic fibers responsible to elasticity. However, these elastic fibers showed structural degenerative changes with aging. Furthermore, there is an age-related decrease of oxytalan elastic fibers responsible to resistance.


CONCLUSIONS
The aged interspinous ligament showed loss of elasticity that could alter the flexion limiting of the vertebral column.
Institute of Orthopedics and Traumatology, University of Sao Paulo, São Paulo, Brazil.
Erika M K P
EM
Barros
Consuelo J
CJ
Rodrigues
Nilson R
NR
Rodrigues
Reginaldo P
RP
Oliveira
Tarcisio E P
TE
Barros
Aldo J
AJ
Rodrigues
D000293:Adolescent; D000328:Adult; D000368:Aged; D000375:Aging / Q000473:pathology*; D002574:Cervical Vertebrae; D003094:Collagen / Q000648:ultrastructure*; D004548:Elasticity; D005260:Female; D006801:Humans; D007593:Joint Instability / Q000473:pathology; D008022:Ligaments / Q000473:pathology* / Q000648:ultrastructure; D008297:Male; D008854:Microscopy, Electron; D008875:Middle Aged
D003094:Collagen