Department of Anaesthesia, Royal Free Hospital, London, UK
It is a disorder of the spinal nerve roots presenting as pain in lumbar pattern. Radicular pain in association with numbness or motor loss constitutes radiculopathy. Any lesion affecting the lumbosacral nerve roots may cause radiculopathy or radicular pain. The most common cause of radicular pain is lumbar disc herniation. Stimulation of nerve fibres in the annulus or posterior longitudinal ligament accounts for the pain. Spinal nerves are more susceptible to compression than peripheral nerve roots and thus easily develop interneuronal fibrosis and radiculopathy.
Disc herniation: movement of disc material beyond the intervertebral space.
Protrusion of disc: neck of the herniated disc is wider than the diameter of the disc.
Disc herniation: neck of the herniated disc is narrower than the widest diameter of the disc.
Disc sequestration: the fragment of disc material breaks from the parent disc.
43.1 Clinical Features
Patients get a band-like sensation of pain travelling through the entire length of the lower extremity. The pain does not follow the path of the nerve roots involved. The pain is shooting or lancinating with an electric shock-like quality. The pain is well defined and localised. It gets worse with flexion and gets better with extension. Pain originating from L1, L2 and L3 is felt in the lower abdomen and groin, while that arising from L4 and L5 and sacral nerve roots is seen in lower extremity. Numbness may also be present. Cross leg straight rising and ipsilateral straight leg rising are positive. Tripod test is also positive (extending the knee with dorsiflexion of the feet while patient is sitting).