Lumbar radiculopathy and back pain

Lumbar radiculopathy is a set of symptoms that include neuropathic pain in the back and lower limb, generated in the lumbar spinal roots. Additionally, patients may experience numbness, weakness, and loss of reflexes. Causes of lumbar radiculopathy include disc herniation, narrowing of the intervertebral foramen, osteophytes, and rarely, tumors. Many patients and their doctors refer to lumbar radiculopathy as sciatica.

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Symptoms of lumbar radiculopathy

Patients with lumbar radiculopathy complain of pain, numbness, tingling, and paresthesia in the distribution of the affected nerve root or roots. Patients may also report weakness and loss of coordination in the affected limb. Muscle spasms and back pain, and pain radiating to the buttocks, are common. Physical examination may reveal decreased sensation, weakness, and decreased reflexes. The Lasegue tension sign is almost always positive in patients with lumbar radiculopathy. Occasionally, patients with lumbar radiculopathy may develop cauda equina compression, which causes lower limb muscle weakness and bladder and rectal symptoms. This is a neurosurgical emergency and should be managed as such.

The most common lumbar discogenic syndromes

Root	Interdisc gap	Suffering reflex	Motor weakness	Sensory impairment (if any)
L4	L3-L4	Knee	Knee extension	Anterior surface of the thigh
L5	L4-L5	Popliteal reflex	Extension of the thumb	Thumb
S1	L5-S1	Achilles (ankle) reflex	Flexion (plantar flexion) of the foot	Lateral edge of the foot

Complications and diagnostic errors

Misdiagnosis of lumbar radiculopathy can lead to the development of lumbar myelopathy, which, if left untreated, can progress to paraparesis or paraplegia.

It is necessary to differentiate tarsal tunnel syndrome, compression of the tibial nerve from lumbar radiculopathy affecting the lumbar nerve roots. It should be remembered that lumbar radiculopathy and neuropathy of the tibial nerve can coexist in the "double compression" syndrome.

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Survey

MRI provides the most comprehensive information about the lumbar spine and its contents and should be performed in all patients with suspected lumbar radiculopathy. MRI is highly reliable and can identify pathology that may be the cause of lumbar myelopathy. For patients who cannot undergo MRI (pacemakers), CT and myelography are reasonable alternatives. If a fracture or bone pathology such as metastatic disease is suspected, radionuclide bone scanning (scintigraphy) or plain radiography is indicated.

While MRI, CT, and myelography provide useful neuroanatomical information, electromyography and nerve conduction velocity studies provide neurophysiological data on the current status of each nerve root and lumbar plexus. Electromyography can also help differentiate between plexopathy and radiculopathy, identifying a coexisting tunnel neuropathy such as garsal tunnel syndrome that may complicate the diagnosis.

If the diagnosis of the cause of lumbar radiculopathy is in question, laboratory testing should be performed, including a complete blood count, ESR, antinuclear antibodies, HLA B-27 antigen, and blood biochemistry to identify other possible causes of pain.

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Differential diagnosis

Lumbar radiculopathy is a clinical diagnosis confirmed by a combination of history, examination, radiography, and MRI. Pain syndromes that may mimic lumbar radiculopathy include myogenic pain, lumbar bursitis, lumbar fibromyositis, inflammatory arthritis, and disorders of the lumbar spinal cord, roots, plexus, and nerves.

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Treatment of lumbar radiculopathy

A multi-component approach is most effective in treating lumbar radiculopathy. Physical therapy consisting of heat and deep relaxation massage in combination with NSAIDs (eg, diclofenac or lornoxicam) and muscle relaxants (eg, tizanidine) are reasonable initial treatments. Caudal or lumbar epidural block may be added if needed. Nerve blocks with local anesthetics and steroids may be highly effective in treating lumbar radiculopathy. Sleep disturbances associated with depression are best treated with tricyclic antidepressants such as amitriptyline, which can be started at 12.5 mg once daily at bedtime.