Degenerative disc disease refers to a variety of pathologies involving displacement of disc material into the spinal canal, such as protrusion, herniation, and sequestration. Degenerative disc disease results in mechanical compression of 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 using 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. A protruded/herniated disc on MRI confirms the diagnosis. Conus medullaris syndrome and cauda equina syndrome 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: protrusion of the vertebral disc nucleus pulposus through the annulus fibrosus
- Disc herniation: (disc extrusion or disc prolapse): complete herniation of the nucleus pulposus through a tear in the anulus fibrosus
- Disc sequestration: extrusion of the nucleus pulposus and separation of a fragment of the disc
- Age: most common at 30–50 years
- Sex: ♂ > ♀ 
- Approx. 80% of all Americans suffer from significant back pain at some point in their lives. 
- Disc herniation is the cause of back pain in roughly 5% of cases.
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 through the annulus fibrosus into the central canal → adjacent nerve root impingement → sensorimotoric deficits in affected nerve root
- Intervertebral discs usually protrude/herniate posterolaterally, as the posterior longitudinal ligament is thinner than the anterior longitudinal ligament.
- Usually, the affected nerve root is the one below the level of disc herniation (e.g., L4–L5 disc herniation leads to L5 radiculopathy).
General clinical features
Acute onset of severe back pain
- Stabbing or resembling electric shock (most commonly of the lower back, called lumbago)
- Radiates to the legs (sciatic pain) or the arms
- 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
|Overview of radiculopathies|
|Radiculopathy||Level of lesion||Sensory deficits||Motor deficits||Reduction of reflexes|
|C3/4 radiculopathy|| || || |
|C5 radiculopathy|| || || |
|C6 radiculopathy|| || |
|C7 radiculopathy|| || |
|C8 radiculopathy|| || || |
|L3 radiculopathy|| |
|L4 radiculopathy|| || || |
|L5 radiculopathy|| |
|S1 radiculopathy|| || |
S2 radiculopathy, S3 radiculopathy, S4 radiculopathy
| || |
Subtypes and variants
Spinal cord compression
- Definition: occurs when the spinal cord is compressed by a lesion such as a tumor, fracture, or ruptured disc
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
Other types of degenerative disc disease
|Overview of conus medullaris syndrome and cauda equina syndrome|
|Syndrome||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 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 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
See “” for details on the distinguishing characteristics and management of the underlying etiology.
- (most common cause)
- Neurological: spinal cord compression, cauda equina syndrome, conus medullaris syndrome, spinal epidural hematoma
- Malignancy: bone metastases (extradural metastatic lesions) n
- Infections: spinal epidural abscess, vertebral osteomyelitis
- Inflammatory: ankylosing spondylitis, reactive arthritis, psoriatic arthritis
Acute spinal cord compression is a surgical emergency. Obtain immediate MRI or CT myelography, give IV steroids for malignant compression, and decompress the cord (e.g., with surgery) as soon as possible!
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
Up to 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