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Home / Spine Non Trauma / Ankylosing spondylitis and DISH
Spine Non Trauma

Ankylosing spondylitis and DISH

Spinal fractures in ankylosing spondylitis and features of Forestier disease

10 questions 2 source pages

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10 questions
Q1What does the sagittal CT show and what should you suspect?▸
  • Most of the spine ankylosed with a break at the C6/7 level
  • No obvious soft tissue swelling; posterior element not involved in this CT cut
  • Suspect ankylosing spondylitis with fracture/pseudoarthrosis
Q2How do you initially manage a suspected AS spine fracture?▸
  • Start with ATLS and immobilize the spine
  • Expect shock - at this level it can be neurogenic shock; rule out other causes, give fluid resuscitation and vasopressor
  • Once stabilized, document neurology
  • Screen the rest of the CT for noncontiguous fractures
  • MRI to look for epidural haematoma
Q3What is the definitive management and why is healing difficult?▸
  • Fractures heal poorly as the spine is stiff with high stress
  • Offer posterior decompression and instrumented fusion
Q4What are the pre-operative challenges in AS spine fracture surgery?▸
  • Risk of GA due to cardiorespiratory comorbidities; adjust medications
  • Difficult airway and ventilation - may need awake fibreoptic intubation
Q5What are the intra-operative challenges in AS spine fracture surgery?▸
  • Positioning in functional/natural position (sandwich prone), do not reduce, fix in situ/original kyphosis, avoid pressure points
  • Posterior extensile approach; loss of landmarks - need CT navigation and neuromonitoring
  • Osteoporotic bone (cement - not in the cervical spine); bleeding
  • Need decompression? If no neurology, no need as want to save more bone bed for fusion; fixation in situ as heroic reduction risks neuro compromise
  • Long segment fusion; defer anterior reconstruction and deformity correction
Q6What are the post-operative complications and epidemiology?▸
  • Pseudoarthrosis (may need secondary anterior procedure), infection, instrumentation failure
  • Wound breakdown (tight skin from kyphosis)
  • SCI incidence 21.1%; multiple and noncontiguous fractures in 13.1%
  • ASAS classification for AS (modified from modified NY criteria due to delay in diagnosis)
Q7What is DISH (Forestier disease)?▸
  • Diffuse idiopathic skeletal hyperostosis - common disorder of unknown etiology with back pain and stiffness
  • XR: flowing candle wax; associated with HLA-B8
  • Defined by non-marginal syndesmophytes over 4 continuous vertebral bodies (3 IVD)
  • 10%, more common in middle-aged males, equal in old; mainly anterolateral
  • Risk factors: DM, hyperlipidaemia, gout
Q8What are the radiological features of DISH?▸
  • Distribution T (R > L) > C > L
  • Preserved disc space, no osteopenia, no degenerative changes
  • SIJ not involved; posterior elements not involved (no facet ankylosis, no intra-articular osseous fusion/sclerosis)
Q9How is DISH treated?▸
  • Activity modification, physical therapy, brace wear
  • NSAIDs and bisphosphonate therapy
Q10What is the association between DISH and total hip replacement?▸
  • Patients with DISH have double the chance of heterotopic ossification (HO)
  • This applies to patients undergoing total hip replacement (THR)
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