Fiche de Revision 2.5 Thinking and Doing
Case 1:
I. Anatomy of the Spine (includes development, bone physiology, histology)
1. Bones
- osteogenesis/ossification: formation of bone by transforming tissue into bone
- endochondral ossification:
1. mesenchymal cells differentiate into chondrocytes to form hyaline cartilage model of bone
2. formation of bone collar, loss of nutrients causes death/ossification of chondrocyte
3. breakdown of bone by osteoclasts to make space
4. vascularization of periosteum, formation of of primary ossification center in the middle
5. osteoblasts fork osteoid, calcification, basis for formation of trabeculae
6. immature woven bone replaced by mature lamellar bone
7. secondary ossification center in epiphysis
- intramembranous ossification:
1. osteoids formed by drilling mechanism of bone vessels
2. bone formation at epiphyseal plate:
- resting zone: chondroblast reserve
, - proliferation zone: chondroblast so multiply
- maturation/hypertrophy: chondroblast hypertrophy/extreme growth
- calcification: chondroblast die and calcify through apoptosis
- ossification: osteoblasts form bone
2. The Spine
- structure:
- cervical: 7 vertebrae
- thoracic: 12 vertebrae
- lumbar: 5 vertebrae
- sacral: 5 fused vertebrae
- coccyx: 4 fused vertebrae
- ligaments
- anterior longitudinal: broad, attached to the bony vertebrae and discs, prevents
hyperextension
- posterior longitudinal: thin, weak, attached only to the discs, prevents hyperflexion
- ligamentum flavum: connect adjacent vertebrae, contains elastic connective tissue, strong
- short ligaments also connect each vertebrae next to each other
, - intervertebral
discs:
- composition: inner gelatinous nucleus pulposus gives elasticity and compressibility ; anulus
fibrosus is a collagen fiber (type I, II) collar which limits expansion of the nucleus, withstands
twisting forces, resists tension to the spine
- facet joints
II. Pathologies of the Back
1. Scoliosis
- definition: lateral deviation of the spin from the vertical axes >10 degrees
- 90% cases do not progress ; >15-20 degrees or progression of the curvature or other
concerning factors requires referral to spinal surgeon
, - types of idiopathic scoliosis:
- congenital: failure of formation of part of the spine (ie. hemi-vertebra) OR failure of
segmentation (ie. block vertebra) ; occurs at 4th-6th embryological week ; diagnosed at birth
- infantile: genetic link ; produces left thoracic curve ; 90% resolve spontaneously ; diagnosed
<3 yrs, using further screening
- juvenile: behaves same as adolescent scoliosis but with greater risk of progression due to
growth ; diagnosed at 3-10yrs
- adolescent: most common ; occurs after 10yrs and before skeletal maturity
- adult/degenerative: occurs after skeletal maturity ; de novo as an advanced form of spinal
degeneration with low-degree lumbar curves and rotatory subluxations OR progressive from
earlier scoliosis
- other types (more severe):
- syndromic: linked to Marfan syndrome, neurofibromatosis, Down
- neuromuscular: such as cerebral palsy
- post traumatic, post infectious: after tuberculosis (seen in developing
countries)
- symptoms: asymptomatic ; back pain
- diagnosis:
- signs: uneven ribs/shoulders/pelvis, thoracic prominence (90% to the right)
- usually during screening programs ; Adam’s forward bend test
- gold standard: upright posterior-anterior long cassette (36’’) frontal and lateral radiograph of
entire thoracic and lumbar spine ; calculate Cobb’s angle
- if in lumbar area: check for spondylolisthesis ; if positive neurological findings: refer for
screening MRI
- classification systems: Lenke ; types/locations of curves
- management and treatment
- serial observation
- every 4 months (at high growth), every 6 months (at low/no growth) ; no follow up for <30
degrees at adulthood
- bracing (only for skeletally immature): orthoses to arrest but not correct scoliosis
- surgical correction: instrumental spinal fusion (of transverse processes)
- prognosis
- factors influencing progression: female gender + skeletal immaturity + current curve
magnitude
- >45 degrees curvature is likely to progress into adulthood and cause clinical problems (back
pain, sciatica)
- >75-90 degrees: pulmonary, GI tract complication
2. Sclerosis
- definition: stiffening of a structure due to replacement of organ tissue by connective tissue
Case 1:
I. Anatomy of the Spine (includes development, bone physiology, histology)
1. Bones
- osteogenesis/ossification: formation of bone by transforming tissue into bone
- endochondral ossification:
1. mesenchymal cells differentiate into chondrocytes to form hyaline cartilage model of bone
2. formation of bone collar, loss of nutrients causes death/ossification of chondrocyte
3. breakdown of bone by osteoclasts to make space
4. vascularization of periosteum, formation of of primary ossification center in the middle
5. osteoblasts fork osteoid, calcification, basis for formation of trabeculae
6. immature woven bone replaced by mature lamellar bone
7. secondary ossification center in epiphysis
- intramembranous ossification:
1. osteoids formed by drilling mechanism of bone vessels
2. bone formation at epiphyseal plate:
- resting zone: chondroblast reserve
, - proliferation zone: chondroblast so multiply
- maturation/hypertrophy: chondroblast hypertrophy/extreme growth
- calcification: chondroblast die and calcify through apoptosis
- ossification: osteoblasts form bone
2. The Spine
- structure:
- cervical: 7 vertebrae
- thoracic: 12 vertebrae
- lumbar: 5 vertebrae
- sacral: 5 fused vertebrae
- coccyx: 4 fused vertebrae
- ligaments
- anterior longitudinal: broad, attached to the bony vertebrae and discs, prevents
hyperextension
- posterior longitudinal: thin, weak, attached only to the discs, prevents hyperflexion
- ligamentum flavum: connect adjacent vertebrae, contains elastic connective tissue, strong
- short ligaments also connect each vertebrae next to each other
, - intervertebral
discs:
- composition: inner gelatinous nucleus pulposus gives elasticity and compressibility ; anulus
fibrosus is a collagen fiber (type I, II) collar which limits expansion of the nucleus, withstands
twisting forces, resists tension to the spine
- facet joints
II. Pathologies of the Back
1. Scoliosis
- definition: lateral deviation of the spin from the vertical axes >10 degrees
- 90% cases do not progress ; >15-20 degrees or progression of the curvature or other
concerning factors requires referral to spinal surgeon
, - types of idiopathic scoliosis:
- congenital: failure of formation of part of the spine (ie. hemi-vertebra) OR failure of
segmentation (ie. block vertebra) ; occurs at 4th-6th embryological week ; diagnosed at birth
- infantile: genetic link ; produces left thoracic curve ; 90% resolve spontaneously ; diagnosed
<3 yrs, using further screening
- juvenile: behaves same as adolescent scoliosis but with greater risk of progression due to
growth ; diagnosed at 3-10yrs
- adolescent: most common ; occurs after 10yrs and before skeletal maturity
- adult/degenerative: occurs after skeletal maturity ; de novo as an advanced form of spinal
degeneration with low-degree lumbar curves and rotatory subluxations OR progressive from
earlier scoliosis
- other types (more severe):
- syndromic: linked to Marfan syndrome, neurofibromatosis, Down
- neuromuscular: such as cerebral palsy
- post traumatic, post infectious: after tuberculosis (seen in developing
countries)
- symptoms: asymptomatic ; back pain
- diagnosis:
- signs: uneven ribs/shoulders/pelvis, thoracic prominence (90% to the right)
- usually during screening programs ; Adam’s forward bend test
- gold standard: upright posterior-anterior long cassette (36’’) frontal and lateral radiograph of
entire thoracic and lumbar spine ; calculate Cobb’s angle
- if in lumbar area: check for spondylolisthesis ; if positive neurological findings: refer for
screening MRI
- classification systems: Lenke ; types/locations of curves
- management and treatment
- serial observation
- every 4 months (at high growth), every 6 months (at low/no growth) ; no follow up for <30
degrees at adulthood
- bracing (only for skeletally immature): orthoses to arrest but not correct scoliosis
- surgical correction: instrumental spinal fusion (of transverse processes)
- prognosis
- factors influencing progression: female gender + skeletal immaturity + current curve
magnitude
- >45 degrees curvature is likely to progress into adulthood and cause clinical problems (back
pain, sciatica)
- >75-90 degrees: pulmonary, GI tract complication
2. Sclerosis
- definition: stiffening of a structure due to replacement of organ tissue by connective tissue
