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Spondylolisthesis
Disorders of Alignment
Spondylolisthesis KEY FACTS
TERMINOLOGY • Anterolisthesis: Anterior displacement of vertebral body relative to one below • Retrolisthesis: Posterior displacement of vertebral body relative to one below
IMAGING • Lateral flexion and extension to evaluate for instability ○ Napoleon's hat sign on AP plain film ○ Instability uncommon in degenerative listhesis – 90% of normal volunteers show 1- to 3-mm translation on flexion-extension radiographs • Spondylolysis may be difficult to identify on MR ○ T1-weighted sagittal images critical ○ CT for definitive diagnosis of subtle fracture
PATHOLOGY • Degenerative (DS)
(Left) Anteroposterior radiograph shows the Napoleon's hat sign. The hat is inverted with the crown ſt representing the anterior cortex of the vertebral body and the brim being the transverse processes. (Right) Sagittal T1WI MR shows postoperative spondylolisthesis following lumbar laminectomy st. There is advanced degenerative changes of the L4-L5 intervertebral disc space with anterior subluxation of L4 on L5. Note the acute superior endplate compression fracture of L1 ſt.
(Left) Sagittal T2WI MR shows grade I spondylolisthesis of L4 on L5 ſt with intervertebral disc degeneration and associated fatty endplate change. There is also degeneration of the interspinous ligament . (Right) Sagittal T2WI MR shows a grade I spondylolisthesis of L4 on L5 with resultant severe foraminal stenosis ſt.
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○ Degenerative retrolisthesis associated with disc degeneration ○ Sagittal oriented facets more likely to have DS Spondylolysis (isthmic) ○ Bilateral in 80% Postsurgical: Loss of posterior element stability Dysplastic: Small L5 body leading to pars lysis Trauma: Severe to produce vertebral body displacement Pathologic: Underlying tumor with instability
CLINICAL ISSUES • 9.2% overall complication rate for treatment of spondylolisthesis ○ Complications related to higher grade spondylolisthesis, DS > isthmic, older age (> 65) • DS + stenosis treated surgically show greater improvement in pain and function over 4 years compared to nonsurgical treatment
Spondylolisthesis KEY FACTS
TERMINOLOGY • Anterolisthesis: Anterior displacement of vertebral body relative to one below • Retrolisthesis: Posterior displacement of vertebral body relative to one below
IMAGING • Lateral flexion and extension to evaluate for instability ○ Napoleon's hat sign on AP plain film ○ Instability uncommon in degenerative listhesis – 90% of normal volunteers show 1- to 3-mm translation on flexion-extension radiographs • Spondylolysis may be difficult to identify on MR ○ T1-weighted sagittal images critical ○ CT for definitive diagnosis of subtle fracture
PATHOLOGY • Degenerative (DS)
(Left) Anteroposterior radiograph shows the Napoleon's hat sign. The hat is inverted with the crown ſt representing the anterior cortex of the vertebral body and the brim being the transverse processes. (Right) Sagittal T1WI MR shows postoperative spondylolisthesis following lumbar laminectomy st. There is advanced degenerative changes of the L4-L5 intervertebral disc space with anterior subluxation of L4 on L5. Note the acute superior endplate compression fracture of L1 ſt.
(Left) Sagittal T2WI MR shows grade I spondylolisthesis of L4 on L5 ſt with intervertebral disc degeneration and associated fatty endplate change. There is also degeneration of the interspinous ligament . (Right) Sagittal T2WI MR shows a grade I spondylolisthesis of L4 on L5 with resultant severe foraminal stenosis ſt.
150
• • • • •
○ Degenerative retrolisthesis associated with disc degeneration ○ Sagittal oriented facets more likely to have DS Spondylolysis (isthmic) ○ Bilateral in 80% Postsurgical: Loss of posterior element stability Dysplastic: Small L5 body leading to pars lysis Trauma: Severe to produce vertebral body displacement Pathologic: Underlying tumor with instability
CLINICAL ISSUES • 9.2% overall complication rate for treatment of spondylolisthesis ○ Complications related to higher grade spondylolisthesis, DS > isthmic, older age (> 65) • DS + stenosis treated surgically show greater improvement in pain and function over 4 years compared to nonsurgical treatment