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- Chronic autoimmiune
- Seronegative arthritis (Rh -ve); Males
- HLA B27 in 90%
- AD with 20% penetrance
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- DISH = Diffuse Idiopathic Skeletal Hyperostosis
- Dx = Presence of non marginal syndesmophytes involving 4 contiguous vertebrae
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- Difference from AS
- AS
- 1. Marginal Syndesmophyte
- 2. Osteopenia
- 3. Disc involved
- 4. SIJ involved
- 5. Younger patients
- DISH
- Non Marginal
- No Osteopenia
- Disc not involved
- No SIJ involvement
- Older Patients
- T spine (Right due to protective aorta pulsation on left) > C > L spine
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- 3 phases
- 1 - Inflammation
- 2 - fibrosis and syndesmophytes formation
- 3 - ossification anf fusion
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- Bone is a target in many inflammatory rheumatoid diseases, such as ankylosing spondylitis and Rheumatoid Arthritis (RA). The generalized effect of inflammation on bone may result in a decreased quality of bone and is associated with an increased risk of fractures and deformities, in ankylosing spondylitis while rheumatoid arthritis is characterized by periarticular osteopenia, systemic osteoporosis and bone erosions.
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3919376/#:~:text=In%20our%20study%20it%20was,values%20in%2068%25%20of%20patients.
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- HX
- Pmhx - AS, medications
- Symptoms - pain, duration, other joints - Achilles tendonitis, eye involvement, heart palpitations, GIT (UC or Crohn), SOB (pulmonary fibrosis)
- Function
- EXTRAskeletal manifestations
- Eye - uveitis
- Heart - carditis, aortic valve disease
- Lungs - pulmonary fibrosis
- GIT - colitis
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- Dx = Modified New York Criteria – at least 1 radio and 1 clinical
- Clinical –
- LBP > 3/12
- Spine Limited ROM
- Limited chest expansion
- Radiological –
- SIJ – unilateral vs bilateral
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- "bamboo spine" with "marginal syndesmophytes", disc space involvement
- Romanus Lesions = shiny corners
- Anderson lesions = erosions that suggest longer disease; can mimic infection
- Dagger sign - ossification of the supraspinous and interspinous ligaments
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- Syndesmophytes are ossifications of the annulus fibrosus and thus are more vertical oriented.
- Osteophytes are growing outward
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- Lung function tests
- XR - SIJ
- CT scan for bone stock
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- Confirm source of pain - hip injection
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- This is a complex primary hip requiring a multidisciplinary approach
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- Ortho - assess LL, discuss about bilateral hip replacement if both involved
- Anaesthetic review - fibre optic intubation for cervical spine stiffness, medication titration, lung function
- Rhuematology - titrate meds. DMARDS e g. TNF alpha inhibitors to stop 2 weeks before due to increased risk of wound break down
- Stand by - necessary equipment, stand by dual mobility cups, plan for hybrid in view of osteopenia
- Stand by senior surgeon as this is a complex primary
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- Positioning - gentle, be careful not to cause spine fractures
- Soft tissue - poor skin, contractures
- Exposures - stand by extensile trochanteric osteotomy, insitu neck cut
- Implant positioning
- Cup = Kyphotic spine, so hips are hyperextended when standing (increased pelvic tilt). We need to place the cup in the functional impingement free ROM
- The key to placing the cup in the correct position is to understand how the pelvis behaves in the dynamic motion between standing and sitting, and to effectively place the cup in a functional impingement-free range of motion
- (i.e., more anteversion and inclination if pelvis is fixed in stuck standing, and
- less anteversion if fixed in stuck sitting; note that we did not say retroversion).
- Femur = Do not put too much anteversion
- Bone
- Poor bone - osteopenic so use hybrid, cemented stem
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- ICU monitoring for lung and heart
- HO prophylaxis - indomethacin 75mg OM 6 weeks
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- Pre op as per above
- Napkin ring osteotomy at the neck with II guidance
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- Malkani 2019 in Arthroplasty –
- Spine Fusion then THR - even up to 5 years) higher risk of dislocation (50% more)
- Buckland et al. JBJS 2017
- THA after spinal fusion. Risks increases with each level of fusion
- Control group 1.55%
- 1-2 levels 2.96%
- 3-7 levels 4.12%
- THR then fusion - lower risk
- Reasons may include decreasing pelvic mobility in a stable, well-healed THA or early postoperative spine precautions after LSF restricting positions of dislocation.
- Consider Dual mobility cups in THR with prior fusion.
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- As one goes from standing to sitting, lumbar lordosis decreases and pelvis should tilt posterior (reduced sacral slope and increased pelvic tilt) to accomodate femoral flexion
- If the spino pelvic junction is fused surgically or biologically, the pelvis moves very little and the acetabular cup is "fixed in space"
- Thus the femur may impinge anteriorly and subsequently, dislocate posteriorly.
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7340719/
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- Any other spondyloarthropathy e.g. Psoriasis
Scenario 2: AS Spine Trauma? (also applicable to DISH spine)
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- CT/ MRI to look for Chalk stick #, epidural hematoma
- Need WHOLE spine MRI - Non contiguous fractures in 13%
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- Fixation principle = “long segment fusion” (3 up and down)
- Reason = long lever arm due to stiff bone
- Can defer anterior procedure as tendency towards bone formation
- Avoid deformity correction (increased risk of cx.)
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- Pre op
- Anaesthesia review for Intubation – fibreoptic
- CT scan for templating
- Osteoporosis - Stand by pedicle screw with augmentation options
- Meds - steroid stress dose
- Bleeding - need GXM, cell saver
- Intraop
- Positioning – gentle prone with Wilson frame to avoid extension
- Landmarks for pedicle screw challenging - II KIV O arm
- Osteoporotic and bleeding bone - pedicle screw augmentation techniques
- Bleeding risk is high - stand by cell saver and gxm and bloods.
- Post op
- Higher risk of pseuarthrosis, non union, infection (meds), wound
Scenario 3 AS Spine Kyphosis
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- Poor function, lack of horizontal gaze, cosmesis and fatigue pain from neck and hip extensors
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- 10/30/40 ° correction
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- aka Ponte Osteotomy aka Posterior column osteotomy
- Excision of posterior column with hinge at disc w disruption of disc
- 10 deg/ segment
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- Excision of posterior cloumn and wedge of VB hinge at VB; No disruption of disc.
- 30-40 deg/ segment
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- Remove of one VB with SPO done on adjacent levels
- 45 deg/ segment
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- Kinking of spinal cord - May need to lengthen anterior column with age
- Nerve roots - consider sacrificing if required