Lumbar Spine Age Changes: Difference between revisions
Tag: Undo |
No edit summary |
||
(2 intermediate revisions by the same user not shown) | |||
Line 1: | Line 1: | ||
{{ | {{partial}} | ||
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. | 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== | ==Biochemical Changes== | ||
{{See also|Fibrous Connective Tissues}} | |||
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. | 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. | ||
Line 25: | Line 26: | ||
{| class="wikitable" | {| class="wikitable" | ||
|- | |- | ||
! | ! Features !! Changes | ||
|- | |- | ||
| 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> | | 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> | ||
Line 57: | Line 58: | ||
{| class="wikitable" | {| class="wikitable" | ||
|- | |- | ||
! | ! Features !! Changes | ||
|- | |- | ||
| Bone Density || <ul><li>Decrease in bone density in the lumbar vertebral bodies, and a decrease in bone strength</li></ul> | | Bone Density || <ul><li>Decrease in bone density in the lumbar vertebral bodies, and a decrease in bone strength</li></ul> | ||
Line 75: | Line 76: | ||
{| class="wikitable" | {| class="wikitable" | ||
|- | |- | ||
! | ! Features !! Changes | ||
|- | |- | ||
| Subchondral bone || <ul><li>Increases in thickness of the subchondral bone of the facet joints during growth, reaching a maximum between 20-50 years</li><li>Thereafter it gets gradually thinner</li></ul> | | Subchondral bone || <ul><li>Increases in thickness of the subchondral bone of the facet joints during growth, reaching a maximum between 20-50 years</li><li>Thereafter it gets gradually thinner</li></ul> | ||
Line 93: | Line 94: | ||
{| class="wikitable" | {| class="wikitable" | ||
|- | |- | ||
! | ! Features !! Changes | ||
|- | |- | ||
| Creep and hysteresis || <ul><li>Increased creep and hysteresis</li><li>Greater set after creep deformation</li><li><strong>Cause of change:</strong> Probably due to the decreased water-binding capacity of the intervertebral discs. They therefore take longer to resume their original structure following deformaiton</li></ul> | | Creep and hysteresis || <ul><li>Increased creep and hysteresis</li><li>Greater set after creep deformation</li><li><strong>Cause of change:</strong> Probably due to the decreased water-binding capacity of the intervertebral discs. They therefore take longer to resume their original structure following deformaiton</li></ul> | ||
Line 105: | Line 106: | ||
With age, the NP becomes less resilient and stiffer, and the AF bears more of the compressive loads applied to the disc. Adaption occurs with the greater loads. Excessive compression can result in ossification of the terminal ends of the collagen fibres of the AF. This ossification can occur in the anterior and posterior margins of the disc where compressive strains are focused during flexion and extension. Excessive vertical load-bearing can result in the development of osteophytes along the entire margin of the vertebral body. This is the vertebral body trying to expand its articular surface area in order to distribute axial loads over a wider area, and therefore lessening the stress applied to the AF during load. In other words, osteophytosis is a natural response to the altered biomechanics of the lumbar spine that are itself due to biochemical changes in the disc. It is not a disease but rather an expected morphological change with age. | With age, the NP becomes less resilient and stiffer, and the AF bears more of the compressive loads applied to the disc. Adaption occurs with the greater loads. Excessive compression can result in ossification of the terminal ends of the collagen fibres of the AF. This ossification can occur in the anterior and posterior margins of the disc where compressive strains are focused during flexion and extension. Excessive vertical load-bearing can result in the development of osteophytes along the entire margin of the vertebral body. This is the vertebral body trying to expand its articular surface area in order to distribute axial loads over a wider area, and therefore lessening the stress applied to the AF during load. In other words, osteophytosis is a natural response to the altered biomechanics of the lumbar spine that are itself due to biochemical changes in the disc. It is not a disease but rather an expected morphological change with age. | ||
The terms osteoarthrosis and degenerative joint disease refer to changes seen in the facet joints. However again, these are morphological consequences of stresses applied to the facet joints over time. The changes are found in regions of greatest and repeated stresses. These are adaptive changes, the structure remodels to account for the applied stresses. However, with severe or repeated stresses, destructive features may occur. | The terms [[Osteoarthritis|osteoarthrosis]] and degenerative joint disease refer to changes seen in the facet joints. However again, these are morphological consequences of stresses applied to the facet joints over time. The changes are found in regions of greatest and repeated stresses. These are adaptive changes, the structure remodels to account for the applied stresses. However, with severe or repeated stresses, destructive features may occur. | ||
The most pivotal reason that all these changes are not diseases, is the fact that they are irregularly associated with pain and disability. There is no correlation between spondylosis and osteoarthrosis in patients with or without symptoms. There is some additional factor that must be the cause of pain. | The most pivotal reason that all these changes are not diseases, is the fact that they are irregularly associated with pain and disability. There is no correlation between spondylosis and osteoarthrosis in patients with or without symptoms. There is some additional factor that must be the cause of pain. | ||
Line 113: | Line 114: | ||
*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]] | ||
[[Category:Spine Anatomy]] |
Latest revision as of 17:33, 30 April 2022
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
- See also: Fibrous Connective Tissues
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 |
|
Proteoglycans |
|
Collagen |
|
Elastic fibres |
|
Non-collagenous proteins |
|
Water content |
|
Structural Changes
Features | Changes |
---|---|
Viable cells |
|
NP and AF distinction |
|
NP changes |
|
Collagen lamellae |
|
Tensile strength |
|
Intervertebral disc height |
|
Vertebral Endplate Changes
Age | Changes |
---|---|
Newborn |
|
Age 10-15 |
|
Age 17-20 |
|
Age 20-65 |
|
Vertebral Body Changes
Features | Changes |
---|---|
Bone Density |
|
Vertical trabeculae |
|
Horizontal trabeculae |
|
Cortical bone |
|
Microfractures |
|
(Schmorl's nodes) |
|
Facet Joint Changes
Features | Changes |
---|---|
Subchondral bone |
|
Articular cartilage |
|
Posterior joint |
|
Cell hypertrophy |
|
Osteophytes |
|
Movement Changes
The biochemical and structure changes that occur have an effect on the mechanical properties and movements of the spine.
Features | Changes |
---|---|
Creep and hysteresis |
|
Range of motion |
|
Spondylosis and Degenerative Joint Disease
Spondylosis refers to the development of osteophytes along the junction of vertebral bodies and their intervertebral discs. Spondylosis is not a disease but a natural consequence of the stresses applied to the spine throughout life. They are reactive and adaptive changes that are due to compensation of biomechanical aberrations. It is an active and purposeful process, not a degenerative one.
With age, the NP becomes less resilient and stiffer, and the AF bears more of the compressive loads applied to the disc. Adaption occurs with the greater loads. Excessive compression can result in ossification of the terminal ends of the collagen fibres of the AF. This ossification can occur in the anterior and posterior margins of the disc where compressive strains are focused during flexion and extension. Excessive vertical load-bearing can result in the development of osteophytes along the entire margin of the vertebral body. This is the vertebral body trying to expand its articular surface area in order to distribute axial loads over a wider area, and therefore lessening the stress applied to the AF during load. In other words, osteophytosis is a natural response to the altered biomechanics of the lumbar spine that are itself due to biochemical changes in the disc. It is not a disease but rather an expected morphological change with age.
The terms osteoarthrosis and degenerative joint disease refer to changes seen in the facet joints. However again, these are morphological consequences of stresses applied to the facet joints over time. The changes are found in regions of greatest and repeated stresses. These are adaptive changes, the structure remodels to account for the applied stresses. However, with severe or repeated stresses, destructive features may occur.
The most pivotal reason that all these changes are not diseases, is the fact that they are irregularly associated with pain and disability. There is no correlation between spondylosis and osteoarthrosis in patients with or without symptoms. There is some additional factor that must be the cause of pain.
References
These are study notes taken from Chapter 13 of:
- Bogduk, Nikolai. Clinical and radiological anatomy of the lumbar spine. Edinburgh: Elsevier/Churchill Livingstone, 2012.