Lumbar spinal stenosis is a narrowing of the spinal canal that may lead to nerve entrapment and subsequent clinical manifestations. The constellation of symptoms includes leg and back pain, neurogenic claudication, difficulty with walking, and other possible complications.
Lumbar spinal stenosis (LSS) is a narrowing of the spinal canal in the lumbar region, in which the surrounding osseous and soft tissue structures lead to nerve compression  . This condition is either congenital  or secondary to a degenerative process, trauma, infection, or surgery . LSS commonly affects the aging population and has a slight predilection for males .
The clinical presentation, which is insidious, initially consists of backache but eventually progresses to include worsening pain, fatigue, weakness, and numbness of the leg(s) . Specifically, patients describe symptoms such as tingling, burning, cramping, fatigue, and stiffness of the lower extremities. Moreover, the leg pain is most often bilateral and radiates distally, particularly with exercise .
As evident in the majority of cases, neurogenic intermittent claudication is the most predominant sign attributed to LSS  . This manifestation is produced and worsened by walking or standing but alleviated with sitting or lying down on the side  . Squatting and bicycle riding may also provide relief since flexion of the trunk leads to widening of the lumbar canal . As the disease advances, the patient is likely to adopt a stooped posture .
LSS in the younger population  may cause radicular symptoms consisting of unilateral neurogenic claudication due to stenosis of the foraminal or lateral recess canal . These patients experience severe leg pain that is worsened with lumbar extension .
Excruciating leg pain, paresthesia, and difficulty with ambulation are all likely sequelae in patients with LSS. Additionally, other possible complications include neurogenic bladder and/or abnormal bowel function   and nocturnal leg cramps .
On visual inspection, the patient may have a stooped posture. Furthermore, examination of the lower back reveals limited extension . Additionally, a neurological assessment may show absent or reduced ankle reflexes as well as sensory deficits .
Patients presenting with the above symptoms should be evaluated by their personal history, clinical picture, physical exam findings, and confirmatory studies. It is important to note that the severity of the clinical presentation does not usually correspond to the degree of stenosis .
The American College of Physicians (ACP) recommends against routine imaging for low back pain unless there are risk factors for infection, malignancy, or other diseases  . However, the traditional workup has included spinal radiography as the initial test. In patients with LSS, this modality is likely to reveal abnormalities such as degenerative changes in the disc or vertebrae, or other disease processes .
A spinal computed tomographic (CT) scan provides visualization of the canal and allows for accurate measurements of its diameter . It may demonstrate narrowed canal with impingement by surrounding structures resulting in a "cloverleaf" or the pathognomonic "trefoil" appearance. To improve sensitivity, intrathecal contrast can be used but this is associated with risks.
Magnetic resonance imaging (MRI), the preferred study for diagnosis of LSS, is useful in the assessment of the spinal cord and associated soft tissue structures such as the cauda equina, epidural fat, intervertebral discs, etc. . Additionally, this test helps rule out differential diagnoses. Specifically, LSS has characteristic appearances on T1 and T2-weighted images.