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Chapter Summary
• Context: Lumbar spinal stenosis (LSS) results from progressive narrowing of the central spinal canal, lateral recesses, or neuroforamina, commonly driven by a combination of disc degeneration, facet joint arthrosis, ligamentum flavum hypertrophy, and degenerative spondylolisthesis. With expanding global life expectancy, its clinical prevalence is surging. The hallmark clinical symptom is neurogenic claudication: buttock and lower-extremity pain, heaviness, or numbness exacerbated by walking and standing, characteristically relieved by lumbar flexion or sitting (the 'shopping cart sign'). Crucially, diagnosis cannot be established from MRI alone because radiological stenosis is highly prevalent in asymptomatic elderly individuals. History, physical examination, and imaging must be strictly correlated. Conservative management represents the first-line therapy for most patients. When incapacitating functional disability persists or progressive neurological deficits occur, surgical decompression reliably relieves claudication and radicular pain. Arthrodesis is not an automatic consequence of decompression and should be reserved for cases with documented segmental instability, significant deformity, or iatrogenic destabilization.
• Chapter Objective: To understand the pathophysiology and clinical features of neurogenic claudication, differentiate central, lateral recess, and foraminal stenosis, interpret standing radiographs, MRI, and CT, structure conservative care pathways, and establish criteria for isolated decompression versus decompression with instrumented fusion.
• Overview and FoundationsDegeneration concurrently alters discs, facets, and the ligamentum flavum, progressively encroaching on neural structures. Lumbar biomechanics explains why symptoms worsen in extension (which narrows canal dimensions) and improve in flexion (which enlarges canal cross-sectional area). Neurogenic claudication must be differentiated from vascular claudication, peripheral neuropathy, hip osteoarthritis, and acute disc herniation. Figure 46.1 illustrates functional walking tests used in clinical evaluation. Plain radiographs evaluate sagittal balance and spondylolisthesis. MRI demonstrates the central canal, lateral recesses, neuroforamina, and root compression. CT details bony facet osteophytosis (Figures 46.2 to 46.5 synthesize the diagnostic algorithm). Conservative management combines physical rehabilitation, core stabilization, medications (NSAIDs, gabapentinoids), and image-guided epidural steroid injections. Surgery is indicated for refractory claudication, intractable radiculopathy, progressive motor weakness, or cauda equina syndrome. Figure 46.6 summarizes the core decision between decompression alone versus decompression with fusion. Open, microscopic tubular, and full-endoscopic decompression techniques are detailed. Figures 46.7 to 46.11 demonstrate minimally invasive decompression in a severe stenotic patient failing conservative therapy. Technological frontiers include AI diagnostics, robotics, navigation, and endoscopic approaches.
• Clinical Application: In clinical practice, asking how posture modifies symptoms is the single most valuable diagnostic clue. Lower extremity pain and heaviness provoked by upright walking and quickly relieved by sitting or leaning forward strongly indicate neurogenic claudication. Peripheral pulses must be examined to rule out vascular claudication. MRI confirms the anatomical stenosis, but must match the patient's symptoms. In appropriately selected surgical candidates, the primary goal is neural decompression. Stenosis alone is not an indication for spinal fusion. Arthrodesis should be added selectively when mobile spondylolisthesis, significant coronal/sagittal deformity, or extensive facet resection (>50% bilateral facetectomy) introduces instability. This distinction avoids unnecessary operative morbidity and cost in elderly patients who require only neural decompression.
