Systemic conditions Flashcards
DISH Ankylosing spondylitis Rheumatoid spondylitis
1
Q
What is DISH?
A
- Diffuse idopathic skeletal hyperostosis
- A very common disorder
- Unknown aetiology
- characterised by presence of non marginal syndesmophytes at 3 successive levels involving 4 contiguous vertebrae
2
Q
What is DISH aka ?
A
- FORRESTIER DISEASE
3
Q
What is DISH define by?
A
- By the PRESENCE of NON MARGINAL SYNDESMOPHYTES AT 4 CONTIGUOUS VERTEBRA, 3 successive levels
- ( different from Ankylosing spondylitis = MARGINAL SYNDESMOPHYTES)
4
Q
What are syndesmophytes?
A
- Vertical outgrowths that extend across the disc space
- Represent CALCIFATION OF THE ANNULUS FIBROSIS and ALL + PLL
5
Q
Where do syndesmophytes occur?
A
- Anywhere in the spine
- usually THORACIC T7-11 region, > on RIGHT side thought to be due to the protective effect of the pulsatile aorta on the left thoracic spine!!!
- Symmetrical ( R+L) in CERVICAL and LUMBAR SPINE
6
Q
What is the epidemiology of difuse idiopathic skeletal hyperostosis?
A
- Overall incidence 6-12%
- uncommon before 50 years
- less common in africans, asians
location
- anywhere in spine
- most common Thoracic spine - Right side >cervical >lumbar
- thought due to protective nature of pulsatile aorta on left thoracic spine
- symmetrical sides in cervical/lumbar
7
Q
What are the risk factors for developing diffuse idiopathic skeletal hyperostosis?
A
- Gout
- Hyperlipidaemia
- diabetes
8
Q
What is DISH associated with?
A
- Lumbar spine stenosis
-
Cervical spine
- hoarness
- sleep apnoea
- cervical myelopathy
- dysphagia and stridor
-
Spine fx and instablity
- Ankylosis creates long lever arm-> displacement with minimal force
- hyperextension injuries are common
9
Q
What are the symptoms and signs of diffuse idopathix skeletal hyperextosis?
A
Symptoms
- Often asymptomatic & discovered incidentally
- thoracic/lumbar spine
- mild chronic pain
- stiffness esp in mane
- aggrevated cold weather
- cervical
- pain & stiffness
- dysphagia
- stridor
- hoarness
- sleep apnoea
10
Q
What investigaitons are useful in dx of DISH?
A
-
xrays
- ap and latera spine
- non marginal syndesmphytes at 3 successive levels ( 4 continous vertebrae)
- thoracic syndesmophytes on right side
- c spine ant bone formation with preservation of disc space ( unlike ank spon)
- lumbar spine- symmetrical syndesmophytes
- other joint involvement -elbow
-
Technetium bone scan
- increased uptake in areas of involvement
11
Q
Is Diffuse idiopathic skeletal hyperextosis related to HLA-B27?
A
- NO associated with HLA-B28 -pt with DISH and DM
12
Q
what are the radiographic findings of DISH
A
- NON MARGINAL SYNDESMOPHYTES at 3 successive levels ( 4 contiguous vertebra)
- Flowing candlewax
- preservation of disc space
- no ostepenia
- no assoc with HLA- B27
- age - older middle age
- No involvement in SI JOINT
cf ankl spon
marginal syndesmophytes, bamboo spine, ossificiation of disc space, osteopenia, strong assoc wiht HLA b27, younger pts, bilateral sacroilitis
13
Q
What is the tx of someone with Diffuse Idopathic Skeletal Hyperextosis?
A
non op
-
activity modification. physical therapy, brace wear, NSAIDS, BISPHOSPHONATES
- most cases
OPERATIVE
-
SPINAL DECOMPRESSION and STABILISATION
- for lumbar stenosis, cervical myelopathy, adult spinal deformity
14
Q
What are the complications of DISH?
A
-
Mortality
- C spine trauma in DISH
- 15% tx operatively
- 67% tx non operatively
- C spine trauma in DISH
-
Heterotrophic ossification
- increased risk of HO after THR
- 30-50% for THR with DISH cf <20% wout
15
Q
Define ankylosing spondylitis?
A
A chronic systemic autoimmune spondyloarthropathy characterised by
- HLA- B27 histocompatablity complex positive
- RH negative- seronegative
- primarily affecting spine
16
Q
What is the pathoanatomy of ankylosing spondylitis?
A
- exact mechanism unknown
- likely autoimmune reaction to an envirnomental pathogen to gentically susceptible individual
- theories in relation to HLA- B27
- HLA- B27 aggregates with peptides in joint -> degenerative cascade
-
Enthesitis
- entheses inflammation -> bony erosions, surrounding soft tissue ossification and joint ankylosis (diff from RA- synovial)
-
Disc space involvement
- Inflammation of the annulus -> bridging of osteophyte formation- syndemosphyte
17
Q
What is the epidemiology of ankylosing spondylitis?
A
- 4:1 Male : female
- affects 0.2% caucasians population
- usually presents at 30 years
- juvenile form <16 yrs inc enthesitis
- fewer than 10% HLA-B27 positive pt have symptoms
-
Genetics
- HLA- B27 on 6th chromosome, B locus
- genetic predisposition but mode of inheritance is unknown
18
Q
What are the dx criteria?
A
- Bilateral sacroilitis
- +/- uveitis
- HLA- B27
22
Q
What are the symptoms of ank spon?
A
-
Lumbosacral pain and stiffness
- most pts
- worse in mane
- insidious onset 3rd decade
-
Neck and upper thoracic pain
- late in life
- acute neck pain- raise suspicion of fracture
- Sciatic
- loss of horizontal gaze
-
shortness of breath
- costovertebral joint involvement-> reduced chest expansion
23
Q
what are the signs of ank spon?
A
-
Limited chest wall expansion
- <2cm more specific dx HLA- B27
-
Decreased spine motion
- Schober test- used to elevate stiffness
-
Kyphotic spine deformity
- chin on chest flexion- see pic
- caused by multiple microfx over time
-
Chin brow to vertical angle
- measured on lateral
- correction of this angle- improved surgical outcome
-
Hip flexion contraction
- exam in supine and sitting position helps differentiate sagittal plane imbalance due to hip flexion contractures or kyphotic spinal deformity
-
Sacroiliac provocation test
- faber test
- flexion/abduction/ ext rotatation of ipislateral hip causes pain
24
Q
What imaging is useful in dx ank spon?
A
- Xrays spine
- full length AP, lateral axial spine
- negative in 50% with spinal Fx
- Squaring of vertebra with vertical Marginal syndemosphytes- see pic
- Late vertebral scalloping - bamboo spine
- measure chin to brow vertical angle
-
xray of pelvis
- ferguson pelvic tilt view
- xray beam 10-15 degree cephalad-see SI
- Bilateral symmetrical sacroiliac erosions
CT
- Will show bony changes but no active inflammation
- best for dx of Cervical Fx
MRI
- Will detect Inflammation - detect early AS
28
Q
What are the tx for spinal deformity with AS?
A
- Kyphotic deformity
- elliminate hip conttractures as reason for deformity
Surgery
-
Lumbar osteotomy
- thoracolumbar kyphotic deformity
- goal to restore sagittal balance & horizontal gaze
- closing wedge (pedicle subtracting) osteotomy
- hinge located on ant spine
- greater deformity correction 30-40o per level
- better fusion & stability due to direct bony apposition
-
Vertebral body resection
- entire vertebral body resected and replaced by cage
-
Single-level opening wedge osteotomy
- hinge on post edde vertebral body
- requires rupture of ALL
-
C7-T1 cervicothoracic osteotomy
- for chin to chest deformity
- slight under correction with final chin to brow angle 10o
- adv vertebral art ext to transv foramen, larger canal diameter
- post op halo immobilisation used as pt poor bone quality
35
Q
What is atlantoaxial subluxation?
A
- Presents in 50-80% pts with RA
- most common to have
- Anterior Subluxation of C1 on C2 ( can have lat/post)
36
Q
what is the mechanism for atlanoaxial subluxation?
A
- A pannus forms between the dens and C1
- Leads to destruction of Transverse Ligament & Dens
37
Q
What measurements are used to define stability on lateral extension-flexion views?
A
-
Atlanto-Dens Interval = ADI
- instability = >3.5mm of motion between flexion and extension views
- instability alone is not an indication for surgery
- > 7mm = alar ligament disruption
- >10mm associated with increased risk of neurological injury= surgery
-
Space available for cord (SAC) & Posterior atanto-dens interval =PADI same thing
- <14 mm assoc with increaed risk of neurological injury = surgery
- >13 mm-most important radiological finding that may predict complete neural recovery after decompression surgery
38
Q
What is the tx of atantoaxial subluxations?
A
Non operative
- IN stable atlantoaxial subluxations
Operative
-
Posterior C1-2 Fusion
- if ADI >10mm (even if no neuro)
- SAC/PADI <14mm (even if no neuro)
- Progressive myelopathy
- indication- must be able to reduce C1 onto C2 - no need to remove C2 post arch
- add transarticular screws avoid use of halo
- Post op ct to identify location of vertebral arteries
-
Occiput -C2 fusion
- if atlantoaxial subluxation is combined with basilar invagination
- resection of C1 post arch required for complete decompression
-
Odontoidectomy
- rarely indicated
- used as a secondary proceedure when there is redisual anterior cord compression due to pannus formation that fails to resolve with time following a posterior spinal fusion
39
Q
What is Basilar invagination?
A
- Superior migration of Odontoid
- Tip of dens migrates above foramen magnum
- present in 40% RA pts
- often seen in combination with fixed atlantoaxial subluxation
41
Q
What lines are useful on lateral xray to dx basilar invagination?
A
- Ranawat C1-C2 index
- Most reproducible measurement
- centre of C2 pedicle to line conecting the anterior & posterior C1 arches
- normal men 17mm, women 15mm
- distance of <13 mm consistent with impaction
43
Q
What is the epidemioogy of subaxial subluxation?
A
- Present in 20% pt wth RA
- Often occurs mutiple levels
- combined upper c spine instability
- lower spine involvment more common with
- steriod use
- males
- seropositive RA
- nodules present
45
Q
What is seen of subaxial subluxation on radiographs?
A
- Subaxial subluxation of vertebral body of >4mm or 20% = cord compression
- Cervical height index ( body height/width) <2.0 almost 100% sensitive and specific for predicting neurologic compromise
