Chapter 7-11: Spinal Stenosis

TEXTBOOK PRESENTATION

The classic presentation is somewhat vague, but persistent back and leg discomfort brought on by walking or standing that is relieved by sitting or bending forward is typically seen.

DISEASE HIGHLIGHTS

1. The clinical syndrome of lumbar spinal stenosis consists of characteristic symptoms and radiographic abnormalities such as spondylolisthesis, disk-space narrowing, facet-joint hypertrophy, neural foramina osteophytes; the estimated prevalence is 12–21% of older adults.

   1. Neurogenic claudication, a variable pain or discomfort with walking or prolonged standing that radiates into the buttocks, thighs, or lower legs, is the most common symptom.

   2. Radicular or polyradicular pain can occur and is not as related to position as neurogenic claudication.

   3. Descriptions of pain from spinal stenosis differ qualitatively from textbook descriptions of vascular claudication (Table 7-9).

2. Neurologic symptoms and signs are variable.

3. Stenosis is seen most often in the lumbar spine, sometimes in the cervical spine, and rarely in the thoracic spine.

4. Spinal stenosis is due to hypertrophic degenerative processes and degenerative spondylolisthesis compressing the spinal cord, cauda equina, individual nerve roots, and the arterioles and capillaries supplying the cauda equina and nerve roots.

5. Pain is worsened by extension and relieved by flexion.

6. Patients with central stenosis generally have bilateral, non-­dermatomal pain involving the buttocks and posterior thighs.

7. Patients with lateral stenosis generally have pain in a dermatomal distribution.

8. Repeating the physical exam after rapid walking might demonstrate subtle abnormalities.

9. About 50% of patients have stable symptoms; when worsening occurs, it is gradual.

   1. Lumbar spinal stenosis does not progress to paralysis and should be managed based on severity of symptoms.

   2. Progression of cervical and thoracic stenoses can cause myelopathy and paralysis and requires surgery more often than lumbar spinal stenosis.

EVIDENCE-BASED DIAGNOSIS

1. History and physical exam

   1. Wide-based gait has an LR+ of 13 for the diagnosis of spinal stenosis.

   2. Table 7-10 outlines the historical and physical exam findings associated with the diagnosis of spinal stenosis.

2. Imaging

   1. Plain radiographs are not necessary: they do not change management, or provide the degree of anatomic detail necessary to guide interventional treatment (such as epidural injection or surgery).

   2. Noninfused CT and noninfused MRI have similar test characteristics.

      1. CT scan: sensitivity, 90%; specificity, 80–96%; LR+, 4.5–22; LR–, 0.10–0.12

      2. MRI: sensitivity, 90%; specificity, 72–99%; LR+, 3.2–90; LR–, 0.10–0.14

      3. Up to 21% of asymptomatic patients over age 65 have spinal stenosis ...