Pathogenesis (development of disease)
Sciatica is a pain condition in the supply area of the sciatic nerve, usually caused by irritation of the nerve roots. If there is concomitant pain in the lumbar spine (LS), the condition is referred to as lumboischialgia.
The cause of sciatica/lumboischialgia is usually a herniated disc (lat. Prolapsus nuclei pulposi, disc hernia, disc prolapse, also disc prolapse, BSP), which can occur suddenly in the event of disc damage (discopathy).
The most common locations (95%) of disc herniation are:
- Between LWK (lumbar vertebral bodies) 4 and 5 → root irritation syndrome L5 (medial BSP), L4 (lateral BSP).
- Between LWK 5 and SWK 1 (sacral vertebral bodies/cruciate vertebrae) → root irritation syndrome S1.
Etiology (causes)
Biographical causes
- Genetic burden/disease – deformities such as spondylolisthesis (slippage of a vertebral body) or spina bifida occulta (German: “hidden split vertebrae”).
Behavioral causes
- Postural causes
- Overweight (BMI ≥ 25; obesity).
Disease-related causes
- Acute irritable condition of the spine
- Acute reversible joint dysfunction – blockage of a joint that spontaneously recedes.
- Autoimmune diseases such as ankylosing spondylitis (synonym: ankylosing spondylitis; chronic inflammatory rheumatic disease with pain and stiffening of joints).
- Intervertebral disc prolapse (herniated disc)
- Disc protrusion – protrusion of the intervertebral disc.
- Discitis – inflammation of an intervertebral disc.
- Inflammatory diseases of the spine as in osteomyelitis (inflammation of the bone).
- Epidural abscess – accumulation of pus in the area of the spinal cord membranes.
- Fracture (bone fracture) in the area of the spine.
- Minor trauma – injuries – such as strains or sprains.
- Neuritis (inflammation of a peripheral nerve or cranial nerve).
- Osteophyte formation – degenerative bone attachments.
- Osteoporosis – disease with reduction of bone mass.
- Osteosclerosis – disease with increase in bone mass, but decreased load capacity.
- Spinal cord tumors
- Spinal varicosis (synonym: spinal varicosis).
- Spinal stenosis – narrowing of the spinal canal.
- Spondylitis (inflammation of the vertebrae)
- Tumor diseases (eg, vertebral metastases).
- Vertebral artery dissection
Medication
- Glucocorticoids (medications for inflammation and when the immune system is overactive – for example, in allergic reactions), these can lead to osteoporosis-related fractures with long-term therapy and thus back pain (three months or longer of systemic corticosteroid therapy increases the risk of osteoporosis by 30-50 percent!)
