Part I. General Considerations -- Definition and Historical Aspects of Sciatica -- Anatomy and Physiology of Normal Sciatic Nerve -- Epidemiology of Sciatica -- Classifications of Sciatica -- Pathophysiological Mechanisms of Sciatica -- Main Clinical Presentations of Sciatica -- Differential Diagnosis of Spinal Sciatica -- Differential Diagnosis of Extraspinal Sciatica -- Paraclinic Evaluations of Sciatica -- No Surgical Treatment of Sciatica (medications, physical therapy, therapeutic injections, alternative therapies) -- Surgical Treatment of Sciatica -- Evolution and Prognosis -- Postoperative Complications -- Part II. Lumbosacral Discogenic Sciatica -- Contained Lumbar Disc Herniation -- Migration of Lumbar Disc Herniation -- Sequestration of Lumbar Disc Herniation -- Central Lumbar Disc Herniation -- Lateral (subarticular) Lumbar Disc Herniation -- Foraminal Lumbar Disc Herniation -- Extraforaminal Lumbar Disc Herniation -- Giant (massive) Lumbar Disc Herniation -- Intradural Lumbar Disc Herniation -- Posterior Epidural Migration of Lumbar Disc Herniation -- Posterior Ring Apophysis Separation -- Recurrent Lumbar Disc Herniation -- Postoperative Sciatica -- Discal Cysts -- Part III. Lumbosacral Non-Discogenic Sciatica -- Spondylosis (degeneration of the lumbar spine) -- Spinal Stenosis -- Spondylolysis -- Spondylolisthesis -- Spondyloarthropathies (spondyloarthritis) -- Rheumatoid arthritis -- Scoliosis -- Lumbosacral extraforaminal stenosis -- Bertolotti syndrome -- Epidural Gas -- Congenital and Developmental Abnormalities of the Spinal Cord/Vertebrae -- Dural Ectasia -- Meningeal Diverticulum and Tarlov cysts -- Arachnoid cysts -- Dural and Intradural Tumors (and pseudotumors) -- Conus medullaris Tumors/Lesions -- Extradural non-vertebral Tumors (and pseudotumors) -- Granulomatous lesions (histiocytosis) -- Spinal Epidural Lipomatosis -- Solitary Vertebral Tumors/Lesions -- Multifocal Vertebral Tumors/Lesions -- Epidural Hematoma -- Subdural Hematoma -- Subarachnoid hematoma -- Vascular Lesions -- Synovial Cyst of the Facet Joints -- Ligamentum Flavum Lesions Cysts -- Ligamentum Flavum Calcification/Ossification -- Ligamentum Flavum Hematoma -- Baastrup disease -- Posterior Longitudinal Ligament Cysts -- Posterior Longitudinal Ligament Ossifications -- Arachnoiditis Ossificans -- Spinal lumbar adhesive arachnoiditis -- Fibrous Adhesive Entrapment of Lumbosacral Nerve Roots -- Conjoined nerve root -- Cordonal Sciatica -- Vertebral osteomyelitis and Spondylodiscitis -- Spinal epidural abscesses -- Spinal subdural abscesses -- Traumatic Lesions (Lumbosacral injuries) -- Pathologic Fractures (Tumoral and osteoporotic) -- Lumbosacral Iatrogenic Lesions -- Spinal Hygromas -- Part IV. Extraspinal (non-spinal) Sciatica -- Abdominopelvic and Retroperitoneal Lesions -- Extraspinal Vascular Lesions -- Varicose sciatica -- Lumbosacral Plexuses -- Extraspinal Lesions of the Sciatic Nerve -- Peripheral Entrapment Neuropathies -- Piriformis Syndrome -- Truncal Sciatica -- Peripheral Neuropathies -- Herpes Zoster (Shingles) Infection -- Extraspinal Musculoskeletal Lesions -- Pregnancy -- Diving accident -- Extraspinal Traumatic Lesions -- Extraspinal Iatrogenic Lesions -- Intramuscular Gluteal Injection -- Extraspinal Iatrogenic Sciatica -- Psychiatric Disorders and Psychological overlay -- Idiopathic Sciatica.