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Thoracolumber fractures

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Thoracolumber fractures

  1. 1. Thoracolumber Fractures Farhad Hussain 8/06/2018
  2. 2. Three Column Model • Denis’ 3 column model of the spine attempts to identify CT criteria of instability of thoracolumbar spine fractures. • This model has generally good predictive value.
  3. 3. Anterior column: • Anterior half of disc and vertebral body (VB) (includes anterior anulus fibrosus (AF)) • Plus the anterior longitudinal ligament (ALL) Middle column: • Posterior half of disc and vertebral body (includes posterior wall of vertebral body and posterior AF), • Posterior longitudinal ligament (PLL) • Pedicles Posterior column: • Posterior bony complex (posterior arch) with interposed posterior ligamentous complex (supraspinous and interspinous ligament, facet joints and capsule, and ligamentum flavum (LF)). • Injury to this column alone does not cause instability
  4. 4. Classification Minor injuries: • Involve only a part of a column and do not lead to acute instability (when not accompanied by major injures). Includes: 1. fracture of transverse process: usually neurologically intact except in two areas: a) L4–5 →lumbosacral plexus injuries (there may be associated renal injuries, check U/A for blood) b) T1–2 →brachial plexus injuries 2. fracture of articular process or pars interarticularis 3. isolated fractures of the spinous process: in the TL spine: these are usually due to direct trauma. • Often difficult to detect on plain x-ray 4. isolated laminar fracture: rare. Should be stable
  5. 5. Major Fractures • The McAfee classification describes 6 main types of fractures.2 A simplified system with four categories • Type 1: Compression fracture: compression failure of anterior column. Middle column intact • (unlike the 3 other major injuries below) acting as a fulcrum, 1. 2 subtypes: a) anterior: most common between T6-T8 and T12-L3 ● lateral x-ray: wedging of the VB anteriorly, no loss of height of posterior VB, no subluxation ● CT: spinal canal intact. Disruption of anterior end-plate b) lateral (rare) 2. clinical: no neurologic deficit
  6. 6. Burst Fractures • Pure axial load →compression of vertebral body →compression • Failure of anterior and middle columns. • Occur mainly at TL junction, usually between T10 and L2.
  7. 7. Radiology a) Lateral x-ray: – Cortical fracture of posterior VB wall – Loss of posterior VB height – Retropulsion of bone fragment from end plate(s) into canal
  8. 8. Radiology b) AP x-ray: • Increase of interpediculate distance (IPD) • Vertical fracture of lamina • Splaying of facet joints: ↑ IPD indicates failure of middle column
  9. 9. Radiology c) CT: demonstrates break in posterior wall of VB with retropulsed bone in spinal canal (average: 50% obstruct ion of canal area), increase in IPD with splaying of posterior arch (including facets)
  10. 10. Radiology • d) MRI: compromise of anterior canal by bone fragment; possible cord compression usually with fragments occupying > 50% of the canal diameter
  11. 11. Clinical • clinical: depends on level (thoracic cord more sensitive and less room in canal than conus region), the impact at the time of disruption, and the extent of canal obstruction a) ≈ 50% intact at initial examination (half of these recalled leg numbness, tingling, and/or weakness initially after trauma that subsided) b) of patients with deficits, only 5% had complete paraplegia
  12. 12. Seat belt Fractures • flexion across a fulcrum anterior to the anterior column (e.g. seat belt) →compression of anterior column & distraction failure of both middle and posterior columns. • May be bony or ligamentous
  13. 13. Fracture-dislocation • failure of all 3 columns due to compression, tension, rotation or shear →subluxation or dislocation 3 subtypes • a) flexion rotation: posterior and middle columns totally ruptured, anteriorly compressed → anterior wedging ● lateral x-ray: subluxation or dislocation. Preserved posterior VB wall. Increased interspinous distance ● CT: rotation and offset of VBs with →canal diameter. Jumped facets ● clinical: 25% neurologically intact. 50% of those with deficits were complete paraplegics
  14. 14. b) shear: all 3 columns disrupted (including ALL) • when trauma force directed posteriorly to anteriorly (more common) VB above shears forward fracturing the posterior arch (→free floating lamina) and the superior facet of the inferior vertebra • clinical: all 7 cases were complete paraplegics c) flexion distraction • radiographically resemble seat-belt type with addition of subluxation, or with compression of anterior column >10–20% • clinical: neurologic deficit (incomplete in 3 cases, complete in 1)
  15. 15. Associated injuries • vertebral end-plate avulsion, ligamentous injuries, and hip and pelvic fractures. • Thoracolumbar fractures may be associated with hemodynamic instability as a result of hemothorax or aortic injury. • Fractures of the transverse processes may be associated with abdominal trauma (e.g. renal injuries at L4–5).
  16. 16. Stability and treatment of thoracolumbar spine fractures Minor injuries • Isolated thoracolumbar transverse process fractures (as demonstrated on spinal CT) do not require intervention or consultation of a spine service. Major spine injuries Denis categorized the instability as: 1st degree: mechanical instability 2nd degree: neurological instability 3rd degree: both mechanical & neurological instability
  17. 17. Anterior Column Injury • Isolated anterior column injuries are usually stable • Treat initially with analgesics and recumbency (bed-rest) for comfort × 1–3 weeks • Diminution of pain is a good indication to commence mobilization with or without external immobilization (corset or TLSO× ≈ 12 weeks) depending on the degree of kyphosis • Vertebroplasty (± kyphoplasty) may be an option • Serial x-rays to rule-out progressive deformity
  18. 18. The following exceptions may be unstable (1st degree) and often require surgery Unstable compression fractures 1. a single compression fracture with: a) loss of >50% of height with angulation (particularly if the anterior part of the wedge comes to a point) b) excessive kyphotic angulation at one segment (various criteria are used, none are absolute. Values quoted: > 30°, > 40°) 2. 3 or more contiguous compression fractures 3. neurologic deficit (generally does not occur with pure compression fracture) 4. disrupted posterior column or more than minimal middle column failure 5. progressive kyphosis: risk of progressive kyphosis is increased when loss of height of anterior vertebral body is >75%. Risk is higher for lumbar compression fractures than thoracic
  19. 19. Middle Column Failure • These are unstable (often requiring surgery) with the following exceptions which should be stable Stable middle column fractures • Above T8 if the ribs and sternum are intact (provides anterior stabilization) • Below L4 if the posterior elements are intact • Chance fracture (anterior column compression , middle column distraction) • Anterior column disruption with minimal middle column failure
  20. 20. Posterior Column Disruption • Not acutely unstable unless accompanied by failure of the middle column (posterior longitudinal ligament and posterior anulus fibrosus). However, chronic instability with kyphotic deformity may develop (especially in children).
  21. 21. Seat-belt type injuries without neurologic deficit • No immediate danger of neurologic injury. Treat most with external immobilization in extension (e. g TLSO).
  22. 22. Fracture-dislocation Unstable. Treatment options: 1. surgical decompression and stabilization: usually needed in cases with a) compression with >50% loss of height with angulation b) or, kyphotic angulation >40° (or >25%) c) or, neurologic deficit d) or, desire to shorten length of time of bedrest 2. prolonged bedrest: an option if none of the above are present
  23. 23. When vertebral body resection (vertebral corpectomy) is performed, options to access: transthoracic or transabdominal approach (or combined), transpedicular (for thoracic spine), lateral (retroperitoneal/ retropleural) approach. Fracture and compression usually occurs at the superior margin of vertebral body, thus start resection at the inferior disc interspace. Followed by strut graft (cage or bone: iliac crest or fibula or tibia). Posterior instrumentation is usually required
  24. 24. Burst fractures • Not all burst fractures are alike. • Some burst fractures may eventually cause neurologic deficit (even if no deficit initially). Surgical indications for burst fractures: burst fracture with any of the following: • Anterior vertebral body height ≤50% of the posterior height • Residual canal diameter ≤50% of normal • Kyphotic angulation ≥ 20° • When the increased interpediculate distance usually present on the initial film widens further on AP x-ray when standing in brace/cast • Neurologic deficit (incomplete) • Progressive kyphosis
  25. 25. Common surgical options for burst or severe compression fractures: 1. If instrumentation alone is needed A) can place pedicle screws in 2 levels above and 2 levels below the fracture B) if the index level can be included (i.E. If the pedicles are intact enough to accept shorter screws), similar biomechanical stability can be achieved by placing screws at the index level (the fractured level) and then just 1 above and 1 below
  26. 26. 2. If decompression of the spinal canal and/or anterior support is needed, corpectomy and strut graft (e.g. with expandable cage) with percutaneous pedicle screws may be used. Approaches: a) from posterior approach e.g. laminectomy with transpedicular approach and impacting bone anteriorly out of canal with a mallet and reverse angled curette, or b) lateral corpectomy and removal of bone from canal
  27. 27. • For those not undergoing surgery (i.e. when surgery is not required or is contraindicated), an option is to treat with recumbency from 1–6 weeks (the duration depending on pain and degree of deformity). • Avoid early ambulation →further axial loading (even in cast). When appropriate, begin ambulation in an orthosis (e.g. molded thoracolumbar sacral orthosis (TLSO) and follow patient for 3–5 months with serial x-rays to detect progressive collapse or angulation which may need further intervention.
  28. 28. Thoracolumbar injury classification and severity score (TLICS) • The TLICS system has been proposed to simplify classification an d discussion of thoracolumbar fractures. • Points are assigned, the scores are summed, and management guidelines are given. • Neurologic deficit, especially when partial, favors surgery.
  29. 29. Surgical Treatment Burst Fractures Choice of Approach: • Surgical considerations: a posterior approach is preferred if there is a dural tear, whereas a burst fracture with partial deficit and canal compromise may be treated more effectively from an anterior approach. • A small progression in angular deformity may occur when posterior stabilization is performed alone (since the injury to the anterior column is not corrected), but by itself usually does not require intervention.
  30. 30. For a posterior approach • In ideal situation (good bone quality, pedicle screw placement goes well (i.e. no fracture, no breach), and non-smoking patient) then one can fuse/rod one above and one below the fracture (using pedicle screws; longer constructs are needed with laminar hooks). • With a short segment fusion like this, approximately 10° of lordosis be lost with time, therefore, one should try to overcorrect a little to accommodate the anticipated settling.
  31. 31. • If the patient does not meet the above criteria (e.g. poor bone quality), an option is to “rod long, fuse short” (e.g. rod 2 levels above and below the fracture but fuse only 1 level above and below) • Remove the hardware when the fusion is solid (e.g. at 8–12 months) – this avoids fusing a nonpathologic segment just to get a better anchor. • Fusing across critical levels (i.e. thoracolumbar junction with T11 or L1 compression fractures) requires that the fusion incorporate 2–3 levels on each side of the junction (the forces of the long segment of the relatively immobile thoracic spine with the lumbar spine at the T-L junction increase the risk of nonunion)
  32. 32. Wound infections • Postoperative wound infect ions with spinal instrumentation are usually due to Staph. aureus. • With titanium hardware it may respond to debridement of devitalized tissue and thorough washout (typically with 3 L of antibiotic irrigation flushed into the wound using a pulse lavage device – avoiding direct irrigation of any exposed dura) without removal of instrumentation, followed by antibiotics. • Persistent infection may respond to. If this is inadequate, removal of instrumentation may occasionally be required
  33. 33. Thank You

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