Neurogenic claudication

Neurogenic claudication (NC), also known as pseudoclaudication, is the most common symptom of lumbar spinal stenosis (LSS) and describes intermittent leg pain from impingement of the nerves emanating from the spinal cord. Neurogenic means that the problem originates within the nervous system. Claudication, from Latin claudicare 'to limp', refers to painful cramping or weakness in the legs. NC should therefore be distinguished from vascular claudication, which stems from a circulatory problem rather than a neural one.

The term neurogenic claudication is sometimes used interchangeably with spinal stenosis. However, the former is a clinical term, while the latter more specifically describes the condition of spinal narrowing. NC is a medical condition most commonly caused by damage and compression to the lower spinal nerve roots. It is a neurological and orthopedic condition that affects the motor nervous system of the body, specifically, the lower back, legs, hips and glutes. NC does not occur by itself, but rather, is associated with other underlying spinal or neurological conditions such as spinal stenosis or abnormalities and degenerative changes in the spine. The International Association for the Study of Pain defines neurogenic claudication as "pain from intermittent compression and/or ischemia of a single or multiple nerve roots within an intervertebral foramen or the central spinal canal". This definition reflects the current hypotheses for the pathophysiology of NC, which is thought to be related to the compression of lumbosacral nerve roots by surrounding structures, such as hypertrophied facet joints or ligamentum flavum, bone spurs, scar tissue, and bulging or herniated discs.

The predominant symptoms of NC involve one or both legs and usually presents as some combination of tingling, cramping discomfort, pain, numbness, or weakness in the lower back, calves, glutes, and thighs and is precipitated by walking and prolonged standing. However, the symptoms vary depending on the severity and cause of the condition. Lighter symptoms include pain or heaviness in the legs, hips, glutes and lower back, post-exercise. Mild to severe symptoms include prolonged constant pain, tiredness and discomfort in the lower half of the body. In severe cases, impaired motor function and ability in the lower body can be observed, and bowel or bladder dysfunction may be present. Classically, the symptoms and pain of NC are relieved by a change in position or flexion of the waist. Therefore, patients with NC have less disability in climbing steps, pushing carts, and cycling.

Treatment options for NC depends on the severity and cause of the condition, and may be nonsurgical or surgical. Nonsurgical interventions include drugs, physical therapy, and spinal injections. Spinal decompression is the main surgical intervention and is the most common back surgery in patients over 65. Other forms of surgical procedures include: laminectomy, microdiscectomy and laminoplasty. Patients with minor symptoms are usually advised to undergo physical therapy, such as stretching and strengthening exercises. In patients with more severe symptoms, medications such as pain relievers and steroids are prescribed in conjunction with physical therapy. Surgical treatments are predominantly used to relieve pressure on the spinal nerve roots and are used when nonsurgical interventions are ineffective or show no effective progress.

Diagnosis of neurogenic claudication is based on typical clinical features, the physical exam, and findings of spinal stenosis on computer tomography (CT) or X-ray imaging. In addition to vascular claudication, diseases affecting the spine and musculoskeletal system should be considered in the differential diagnosis.

Neurogenic claudication commonly describes pain, weakness, fatigue, tingling, heaviness and paresthesias that extend into the lower extremities. These symptoms may involve only one leg, but they usually involve both. Leg pain is usually more significant than back pain in individuals who have both. NC is classically distinguished by symptoms improving or worsening with certain activities and manoeuvres. Pain may occur with walking, standing, and back extension. Sitting and bending or leaning forward tend to provide relief. Patients may also report that pain is worse while walking down stairs and improved while walking up stairs or using a bicycle or shopping cart. A positive "shopping cart sign" refers to the worsening of pain with spinal extension and improvement with spinal flexion.

Whilst these common symptoms are usually present in many patients with NC, rarer and more serious symptoms can occur in severe cases of NC. In extreme cases of NC constant discomfort, pain or numbness is experienced. This results in patients to have decreased mobility and function as excessive or constant movements cause pain. Exercise and prolonged walking often become difficult and are triggers of pain, tiredness, numbness and heaviness in the legs, lower back and hips. Common tasks such as standing upright for an extended duration or picking up heavy objects may become increasingly difficult to perform. In addition, patients with severe NC may experience difficulties sleeping as lying down on their back causes discomfort and pain. In very extreme cases, bowel or bladder dysfunction can occur. However, this is a consequence of the underlying cause of NC rather than the condition itself. As most causes of NC involve increased pressure or damage to the nerves in the lower spine, damage and pressure on the nerves that extend to the bowel or bladder may occur, leading to bowel or bladder dysfunction.

On physical examination, patients with NC have normal peripheral pulses. The neurologic exam, straight leg raise, and femoral nerve stretch are typically normal. Abnormal signs may be revealed if the patient is observed walking until they exhibit NC. For example, a positive "stoop test" is observed if bending forward or stooping while walking relieves symptoms. Occasionally, patients may have other signs such as sensory loss or gait changes.