Clinical presentation and symptoms
Patients describe the pain in radiculopathy as sharp and "stabbing". It is significantly more intense than regular muscle spasm. A characteristic feature is proximal-to-distal radiation: pain shoots from the lower back all the way to the foot and toes.
Pain is exacerbated in the upright position, with any lumbar movements, as well as when sneezing or bringing the chin to the chest.
Neurological examination reveals:
- Spasm of the back and affected limb muscles.
- Positive Lasègue's sign.
- Antalgic posture: scoliosis (lateral spinal curvature) frequently develops, which significantly diminishes when the patient lies down.
The L5 and S1 roots are most commonly affected, L4 lesions are less common, and upper lumbar roots are extremely rare.
Topical diagnosis: how to differentiate L5 and S1 lesions
To precisely determine the level of compression, the neurologist assesses the pain radiation zone, areas of sensory loss (hypesthesia), reflex status, and muscle strength.
| Sign | S1 radiculopathy | L5 radiculopathy |
|---|---|---|
| Pain Radiation | Lower back → buttock → posterior thigh → posterolateral lower leg → lateral edge of the foot and outer toes | Lower back → buttock → anterolateral thigh and lower leg → medial edge of the foot and great toe |
| Zone of Hypesthesia | Lateral lower leg, outer toes (less commonly posterior thigh) | Lateral lower leg and great toe |
| Reflexes | Achilles reflex is lost | Preserved |
| Motor Paresis | Weakness of the gastrocnemius muscle (sometimes foot and toe flexors/pronation) | Weakness of the extensor hallucis longus (less frequently foot dorsiflexors/pronators) |
Differential diagnosis with other types of pain
It is important to differentiate true radiculopathy from other types of back pain:
- Lbalgia: subacute or chronic aching pain restricted to the lower back. Triggered by physical exertion or hypothermia. The patient may freeze in an awkward posture as movement worsens the pain.
- Lumboischialgia: pain encompasses the back, buttock, and posterolateral aspect of the leg. It is based on musculoskeletal disorders or myofascial syndromes (involving the piriformis, gluteal, and iliopsoas muscles). The main difference from radiculitis is that pain does not reach the foot and toes.
Complications: cauda equina syndrome
A large intervertebral disc herniation (e.g., a sequestered herniation with cranial fragment displacement) can cause massive compression of the spinal canal structures. This leads to the development of acute cauda equina syndrome.
Clinical manifestations (red flags):
- Pronounced lower paraparesis (weakness in both legs).
- Loss of all modalities of sensation in the anogenital area (perineum).
- Pelvic organ dysfunction: flaccid bladder paresis, acute urinary retention, or paradoxical ischuria (ischuria paradoxa — dribbling of urine from an overdistended bladder).
This condition requires emergency hospitalization in a neurosurgical department.
Principles of treatment
The management strategy for a patient with discogenic radiculopathy differs from the treatment of nonspecific back pain.
- Regimen: short-term bed rest is indicated for maximum offloading of the lumbar spine. Sudden bending, twisting, and pain-provoking postures are strictly prohibited.
- Pharmacotherapy: simple analgesics or nonsteroidal anti-inflammatory drugs (NSAIDs) are used. In case of very intense pain, short-term prescription of weak opioid analgesics (tramadol) is possible.
- Local therapy: epidural blocks—administration of corticosteroids and local anesthetics directly into the affected nerve root area—show high efficacy.
- Surgical treatment: disc herniation removal is performed when adequate conservative therapy fails, in case of progressive limb weakness, and as an emergency procedure for cauda equina root compression (absolute indication).
For rapid topical diagnosis: S1 is the posterior leg, loss of the Achilles reflex, and gastrocnemius weakness. L5 is the lateral aspect, preserved reflexes, and great toe weakness.
Class and exam questions
How to distinguish radiculopathy from lumboischialgia?
In lumboischialgia, pain is localized in the lower back, buttock, and posterolateral surface of the leg, but never reaches the foot and toes. In radiculopathy, pain radiates proximally-distally all the way to the foot.
Is bed rest beneficial for back pain?
In acute nonspecific pain, it is harmful and delays recovery. However, in discogenic radiculopathy, short-term bed rest is recommended for maximal spinal offloading.
In what cases does a patient with radiculopathy need emergency surgery?
An absolute indication for emergency surgery is the development of cauda equina syndrome. Surgical intervention is also indicated for progressive limb weakness or failure of conservative therapy.
What else to study on this topic
- Myofascial syndromes in lumboischialgia
- Lumbosacral plexus neuropathies
- Pharmacotherapy of acute nonspecific back pain
- MRI semiotics of intervertebral disc herniations
- Acute cauda equina syndrome
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