Lumbar Spine Age Changes: Difference between revisions
No edit summary |
No edit summary |
||
Line 20: | Line 20: | ||
| Water content || <ul><li>Decrease in water content with age from 88% at birth, to 65-72% by age 75.</li><li>Most of the dehydration occurs during childhood and adolescence, with a final reduction of AP water content by 6% from early adulthood to old age</li><li>Factors leading to reduced water content: loss of proteoglycans, change in KS/CS ratio, increased collagen and collagen-proteoglycan binding leaving fewer polar groups of the PGs to bind water</li></ul> | | Water content || <ul><li>Decrease in water content with age from 88% at birth, to 65-72% by age 75.</li><li>Most of the dehydration occurs during childhood and adolescence, with a final reduction of AP water content by 6% from early adulthood to old age</li><li>Factors leading to reduced water content: loss of proteoglycans, change in KS/CS ratio, increased collagen and collagen-proteoglycan binding leaving fewer polar groups of the PGs to bind water</li></ul> | ||
|} | |} | ||
==Structural Changes== | |||
{| class="wikitable" | |||
|- | |||
! Header text !! Header text | |||
|- | |||
| Viable cells ||<ul><li>Viable cells decrease in the NP.</li><li>Proportion of cells that exhibit necrosis rises from 2% in infancy, to 50% in young adults, to 80% in old age. Lipofuscin granules accumulate</li></ul> | |||
|- | |||
| NP and AF distinction ||<ul><li>There is less distinction between the NP and AF as the disc becomes more fibrous.</li><li>They coalesce, and the NP becomes encroached by the AF.</li></ul> | |||
|- | |||
| NP changes ||<ul><li>The NP becomes more solid, dry, and granular after middle age. There is less ability to exert fluid pressure with a drier more fibrous NP, with it being less able ot transmit weight directly, and less able to exert radial pressure on the AF. There is therefore a greater vertical load borne by the AF.</li></ul> | |||
|- | |||
| Collagen lamellae ||<ul><li>Collagen lamellae of the AF increases in thickness, and becomes more fibrillated, and cracks and cavities may develop.</li><li>These can enlarge and become clefts and fissures. There is an increase in incomplete lamellae</li><li>These changes can occur due to repeated minor insults with an overloaded AF during trunk movements over the course of activities of daily living.</li></ul> | |||
|- | |||
| Tensile strength ||<ul><li>Reduction in the tensile strength of the AF, but no simple relationship between age and tensile properties.</li></ul> | |||
|- | |||
| Intervertebral disc height ||<ul><li>Intervertebral disc height ''increases'' with age.</li><li>There is an increase in AP diameter by 10% in females, and 2% in males, and a 10% increase in height of most discs. The upper and lower surfaces of the discs increase in convexity.</li><li>Disc height maintenance with age is "normal."</li><li>Any loss of trunk stature is due to decreases in vertebral body height.</li><li>Disc narrowing is due to a process other than ageing.</li></ul> | |||
|} | |||
==References== | ==References== | ||
Bogduk, Nikolai. Clinical and radiological anatomy of the lumbar spine. Edinburgh: Elsevier/Churchill Livingstone, 2012. | Bogduk, Nikolai. Clinical and radiological anatomy of the lumbar spine. Edinburgh: Elsevier/Churchill Livingstone, 2012. | ||
[[Category:Lumbar Spine Anatomy]] | [[Category:Lumbar Spine Anatomy]] |
Revision as of 19:38, 14 April 2021
Standard descriptions of the lumbar spine refer to the healthy, young, adult spine. There is also variation to what is "normal" for the lumbar spine. With aging you see fairly uniform changes in the lumbar spine, and so normality changes with advancing age. Many changes in the lumbar spine are not associated with symptoms and are therefore not pathological, but rather part of the normal ageing process.
Biochemical Changes
The changes in collagen, proteoglycans, and elastic fibres have major biomechanical effects on the disc. With age they become drier, and with an increase in collagen and reduction of elastin, they become more fibrous and less resilient. The increased collagen and collagen-proteoglycan binding leads the disc to become stiffer (more resistant to deformation), and the decreased water-binding capacity means they are less able to recover from creep deformation. This can lead to a change in mobility.
Area of Change | Biochemical Changes |
---|---|
Metabolism | In childhood, the disc adapts to anaerobic metabolism after the regression in infancy of the meagre blood supply to the disc. |
Proteoglycans |
|
Collagen |
|
Elastic fibres | Reduction in the AP from 13% at age 26 to 8% at age 62 |
Non-collagenous proteins | Increase in concentration, with the appearance of distinctive non-collagenous proteins. Their function is unknown. |
Water content |
|
Structural Changes
Header text | Header text |
---|---|
Viable cells |
|
NP and AF distinction |
|
NP changes |
|
Collagen lamellae |
|
Tensile strength |
|
Intervertebral disc height |
|
References
Bogduk, Nikolai. Clinical and radiological anatomy of the lumbar spine. Edinburgh: Elsevier/Churchill Livingstone, 2012.