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Chapter Summary
• Context: Lumbar disc herniation (LDH) is one of the most frequent causes of lumbosciatic radicular pain and occupational disability in productive-age adults. Pathophysiology combines disc degeneration, annular fissure, nucleus pulposus displacement, mechanical root compression, and intense local chemical inflammation. Crucially, this robust inflammatory response explains a central aspect of its natural history: extruded and sequestered disc fragments frequently undergo spontaneous enzymatic and macrophage-mediated resorption. Therefore, the radiographic volume of a herniation does not automatically dictate surgical intervention. Diagnosis requires rigorous clinicoradiological correlation between dermatomal pain distribution, myotomal motor weakness, reflex changes, neural tension signs (Lasègue/SLR test), and MRI findings. The vast majority of patients without red flags improve with conservative management. Progressive motor deficits and cauda equina syndrome represent urgent surgical exceptions. When indicated, discectomy can be performed via microdiscectomy or full-endoscopic techniques, with clinical outcomes dependent primarily on precise patient selection.
• Chapter Objective: To understand the epidemiology and pathophysiology of lumbar disc herniation, recognize lumbar radicular syndromes, perform accurate clinicoradiological correlation, select appropriate non-operative or surgical pathways, and recognize major complications, including recurrence, dural tears, epidural fibrosis, and cauda equina emergencies.
• Overview and FoundationsFigure 45.1 differentiates protrusion, extrusion, and sequestration, while axial location (central, paracentral, foraminal, extraforaminal) determines which nerve root is compressed (traversing vs exiting). Mechanical distortion and inflammatory cytokine release generate radicular pain. Bilateral neurological examination mapped to dermatomes (Figure 45.2) localizes the affected level. Lasègue and neural tension tests confirm root irritation. Red flags—saddle anesthesia, bowel/bladder dysfunction, bilateral sciatica—mandate immediate cauda equina syndrome evaluation. MRI characterizes morphology, location, and neural compression; however, asymptomatic bulges are prevalent (Figure 45.4 also details associated Modic changes). Without neurological deterioration, natural history strongly favors conservative care (analgesia, physical therapy, activity modification). The clinical case in Figures 45.5 and 45.6 demonstrates complete spontaneous resorption of a massive extrusion. Surgery is indicated for cauda equina syndrome, progressive motor deficits, or refractory incapacitating pain after 6-8 weeks of conservative care. Microdiscectomy and full-endoscopic discectomy represent validated surgical options. Complications include dural tears, recurrence, neural injury, and epidural scarring. Modern evolutions—endoscopy, annular closure devices, biologics, navigation—continue to refine minimally invasive management.
• Clinical Application: In clinical practice, the fundamental error is 'operating on the MRI'. The herniation must explain the patient's exact clinical presentation. Dermatomal distribution, motor deficit, reflex depression, and straight leg raise test must concord with the anatomical MRI level. In the absence of severe motor deficits or cauda equina syndrome, spontaneous fragment resorption makes conservative management the primary strategy. A large extruded fragment has a higher likelihood of resorption than a contained protrusion. Conversely, urinary retention, saddle numbness, or progressive foot drop require urgent surgical decompression. When surgery is indicated, the goal is neural decompression with minimal tissue disruption. Endoscopic and tubular techniques offer equivalent long-term decompression with less muscle trauma. Patients should be counseled that postoperative recurrent pain may stem from epidural scarring rather than immediate recurrence.
