Table 2.

WFNS Spine Committee Recommendations on Natural Course and Diagnosis of Lumbar Spinal Stenosis

Natural course  Approximately 30% of patients with lumbar spinal stenosis (LSS) are expected to worsen, but 30% may improve with conservative measures There are predictive signs/symptoms that they will worsen:  • Dural sac cross-sectional area <50 mm2  • Presence of radicular symptoms and back pain  • Presence of degenerative spondylolisthesis and/or scoliosis  • Symptom duration >1 year

Radiologic diagnosis  MRI is the most appropriate noninvasive test for the diagnosis of LSS and the second is CT scan. CT myelography is appropriate if MRI is contraindicated or inconclusive There is no correlation between clinical symptoms or function with the presence of anatomic narrowing of the spinal canal on MRI, CT, or myelo-CT Qualitative radiologic criteria describe adequately spinal stenosis in central, lateral, or foraminal stenosis There are some radiologic signs that describe instability:  • Direct signs on functional radiograms  • Indirect signs on MRI and CT such as Modic changes, end-plate edema, extended discal vacuum, traction spurs, synovial cysts, annular tears, spondylolisthesis, and “facet fluid sign”

Electrophysiological diagnosis  Routine electrophysiological tests (EMG, nerve conduction study, F-wave response, H-reflex, SSEP, MEP) have no diagnostic value for LSS Electrophysiological tests do not predict the outcome of patients with LSS

WFNS, World Federation of Neurosurgical Societies; MRI, magnetic resonance imaging; CT, computed tomography; EMG, electromyography; SSEP, somatosensory evoked potential; MEP, motor evoked potential.