Spinal Stenosis Sub-Syndromes
The posture of patients with lumbar spinal stenosis while walking is typically kyphotic. Patients will sometimes describe how they can walk for longer periods in a store only by leaning forward supported by a shopping cart. Extension of the spine will often provoke symptoms while flexion will relieve them. Thus, many patients will stop walking, and bend over or squat to relieve their pain. The patients may only be able to walk a few hundred meters but may be able to ride a bicycle for several kilometers.3
Although more variation exists in the complaints of patients with spinal stenosis than any other syndrome producing low back pain, there are four primary sub-syndromes:
- Neurogenic Intermittent Claudication
- Radicular Pain (Sciatica)
- Atypical Leg Pain
- Cauda Equina Syndrome
Cauda equina syndrome due to massive lumbar disc prolapse must be positively diagnosed or dismissed prior to any successful course of treatment for symptoms of lumbar spinal stenosis. Considered rare (occurring in 1 in 100,000 to 1 in 33,000 of adults)5 the important features of this syndrome are: rapid progression of neurologic signs and symptoms in a patient with a known disc herniation; bilateral leg pain and neurologic symptoms that frequently accompany it; presence of caudal anesthesia; presence of genitourinary dysfunction manifested by overflow incontinence or retention; and loss of rectal sphincter tone sometimes accompanied by fecal incontinence. It is important to assess the presence of cauda equina syndrome quickly in patients presenting symptoms of lumbar spinal stenosis. Delayed surgical intervention may result in persistent neurologic dysfunction.
Pseudoclaudication is a syndrome unique to spinal stenosis and also its most common symptom. Intermittent claudication is defined as pain in the buttocks, thighs, and legs brought on by either prolonged standing or exercise in the erect posture. This symptom typically is relieved by various maneuvers that flex the lumbar spine such as bending forward, either in a sitting or lying position.
Peripheral symptoms are classically those of sciatica, which is described by patients as pain in the lower back and hip, radiating down the back of the thigh into the leg. A history of numbness, and associative weakness, or tingling is suggestive of a radiculopathy.
Atypical leg pain occurs with non-radicular distribution, vague localization, and inconsistencies in location and presentation.4