- Clinical science
Degenerative disc disease refers to a variety of pathologies with displacement of disc material into the spinal canal, such as protrusion, herniation, and sequestration. Degenerative disc disease results in mechanical compression on either the spinal cord or a nerve root. The most common symptoms of disc disease are radicular pain in the dermatome of the compressed nerve root, muscle weakness, and loss of deep tendon reflexes in the indicator muscles. The location of the lesion can often be determined by the patient's neurological deficits. In most cases of lumbosacral disc disease, L5 nerve compression is present, which leads to reduced sensitivity in the lateral leg, dorsum of the foot, and weakness in extending the big toe. MRI confirms the diagnosis by showing the protruded/herniated disc. Conus medullaris syndrome and cauda equina syndromes are severe forms of disc herniation that may present with paresis, sensory deficits, and urinary and bowel incontinence. They require urgent decompression via surgical intervention. Most spinal disc herniations, however, can be treated conservatively with analgesia and by maintaining physical activity.
- Disc protrusion: Pressure on the vertebra causes the gelatinous core, called the nucleus pulposus, to move and press against the annulus fibrosus. This bulge compresses a spinal nerve and thus causes pain.
- Disc herniation: (= disc extrusion or disc prolapse): A tear in the annulus fibrosus results in extrusion of the nucleus pulposus and potential compression of the spinal nerve
- Disc sequestration: Extrusion of the nucleus pulposus and separation of a fragment that enters the spinal canal and may cause compression of the spinal nerve.
- Age: most common at 30–50 years
- Sex: ♂ > ♀
- Approximately 80% of all Americans suffer from significant back pain at some point in their lives
Epidemiological data refers to the US, unless otherwise specified.
- The intervertebral disc consists of a dense outer ring (annulus fibrosus) and a gelatinous core (nucleus pulposus).
- Compression, tension, shear, and torque stresses on the spinal disc → degenerative changes (e.g., dehydration, annular tear) → disc protrusion or herniation → adjacent nerve root impingement → sensorimotoric deficits in affected nerve root
- Acute onset of severe back pain
- Paresthesia of affected dermatome
- Muscle weakness and atrophy
- Loss of deep tendon reflexes in the indicator muscles
- Pain increases with pressure (e.g., from coughing or sneezing)
- Short walks and changing position reduces the pain
A sudden decrease in pain concomitant with an increase in the degree of paralysis can be a warning sign of neuronal death!
|Sensory deficits||Motor deficits||Reduction of reflexes|
|C3/4 radiculopathy|| |
|C5 radiculopathy|| |
|C6 radiculopathy|| |
|C7 radiculopathy|| |
|C8 radiculopathy|| || |
|S1 radiculopathy|| |
| || |
- Definition: occurs when the spinal cord is compressed by a lesion such as a tumor, fracture, or ruptured disk
Clinical features: depend on the location of the spinal compression
- Common features: back pain, radicular pain (follows dermatomal distribution of affected nerve), and neurological deficits below the level of the lesion (first sensory abnormalities, followed by motor and/or bladder/bowel dysfunction)
- cauda equina syndrome and conus medullaris syndrome :
- Patients may develop symptoms of isolated cauda equina syndrome, isolated conus medullaris syndrome, or a combination of the two.
- Considered a medical emergency!
- Immediate management
- Surgical management: definitive treatment
- Decompression surgery
- Stabilization surgery
- Radiation therapy: indicated if tumor is inoperable and following surgery; controls local tumor growth and significantly reduces pain
|Etiology||Onset||Pain||Motor symptoms||Sensory symptoms||Urogenital and rectal symptoms|
|Conus medullaris syndrome|| || |
|Cauda equina syndrome|| || |
- Physical examination (reflexes, motor strength, sensory deficits)
Straight leg-raising maneuvers
- Straight leg raise test (Lasegue's sign): straight leg of patient is raised → ↑ pain in the ipsilateral leg with radiation to the motor or sensory area of the affected nerve root.
- Bragard sign: straight leg of patient is raised → ↑ pain in the ipsilateral leg → leg is lowered to just below this point → ankle is dorsiflexed → reproduction of pain
- Crossed straight leg raise test: opposite straight leg of patient is raised → increased pain in contralateral leg with radiation into the motor/sensory area of the affected nerve root.
- Spurling's maneuver (neck compression test)
- If MRI is unavailable or cannot be conducted
- Better for analysis of bone structure (e.g. prior to surgery)
- Plain radiographs: to exclude other pathologies (e.g., spine tumors, instabilities); preoperatively
|Common etiologies||Typical features||Diagnostics||Therapy|
|Musculoskeletal||(most common cause of lower back pain)|| |
| || |
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(extradural metastatic lesions)
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|Infectious||Spinal epidural abscess|| |
|Inflammatory|| || |
|Others|| || || |
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|Spinal epidural hematoma|| || || |
The differential diagnoses listed here are not exhaustive.
- Physiotherapy with exercises strengthening the back
- No bed rest, but continuation of daily activities
- Local heat
- Analgesics (e.g., NSAIDs)
- Periradicular therapy (PRT): CT-navigated injection of a local anesthetic (e.g., ropivacaine) and glucocorticoids at the intervertebral foramen to reduce inflammation and edema at the affected nerve root
80% of all disc herniations are self-limiting and usually resolve within 4 weeks!
- Significant or progressive neurological deficits
- Bladder or bowel incontinence
- Elective indications: massive radicular pain which cannot be relieved by conservative and/or medical treatment
- Procedure: microsurgical intervention with nerve decompression
- Surgical complications