Lumbar spinal stenosis is a medical condition in which the spinal canal narrows, compressing nerves and blood vessels at the level of the lumbar vertebrae. Spinal canal stenosis can also affect the cervical or thoracic vertebrae, and these conditions are known as cervical spinal stenosis or thoracic spinal stenosis. Lumbar spinal stenosis can cause pain or abnormal sensations in the lower back or buttocks, loss of sensation in the legs, thighs, feet, or buttocks, or loss of bladder and bowel control. The exact cause of lumbar spinal stenosis is not clear. Narrowing of spinal structures such as the spinal canal, lateral cavities, or intervertebral foramen is present, but is not sufficient to cause lumbar spinal stenosis alone. Many people who have an MRI have these changes but do not have symptoms. These changes are usually seen in people with degenerative spinal disease that occurs with aging. Lumbar spinal stenosis may also be caused by osteoporosis, osteophytes, tumors, trauma, or skeletal dysplasia such as dysplasia malformans and chondrodysplasia. Specialists diagnose lumbar spinal stenosis using a clinical history, physical examination, and CT or MRI. Electromyography may be helpful if the diagnosis is unclear. Age and widespread pain that worsens with prolonged standing or walking and is relieved by sitting, lying down, bending forward at the waist, and walking with long strides are helpful signs that may include: focal weakness or decreased sensation in the legs, decreased reflexes in the lower extremities, and difficulty with balance. All of the above signs are strongly associated with lumbar spinal stenosis. Most people with lumbar spinal stenosis are candidates for initial conservative, nonsurgical treatment. Nonsurgical treatments include medications, physical therapy, and injections. Surgery may slightly improve outcomes but carries more risks than conservative treatment. Overall, there is limited evidence to support the choice of surgical or nonsurgical treatment for people with symptoms of lumbar spinal stenosis. Similarly, evidence to support the use of acupuncture is also limited. Lumbar spinal stenosis is a common condition that causes significant morbidity and disability. It is the most common reason for spinal surgery in people older than 65 years. The condition affects more than 200,000 people in the United States. Understanding the meaning of the signs and symptoms of lumbar stenosis requires understanding what the syndrome is and how common it is. A recent review of lumbar spinal stenosis in the Journal of the American Medical Association Clinical Review Series confirmed that the syndrome can be considered when lower extremity pain occurs with back pain. The syndrome occurs in 12% of community-dwelling elderly men and up to 21% of retired men. The symptoms of lumbar spinal stenosis are similar to those of vascular claudication, which is why the term pseudoclaudication is used to describe the symptoms of lumbar spinal stenosis. These symptoms include pain, weakness, and tingling in the legs, which may radiate to the feet. Additional symptoms in the legs may include fatigue, heaviness, weakness, tingling, numbness, or cramping, in addition to bladder symptoms. Symptoms are most often symmetrical and bilateral, but may be unilateral. Leg pain is usually more bothersome than back pain. Pseudoclaudication, now referred to as neurogenic claudication, worsens with standing or walking, improves with sitting, and is often associated with postures that stretch the lumbar cord. Lying on the side is more comfortable than lying on the back, as it allows for greater lumbar flexion. Vascular claudication may mimic those of neurogenic claudication, with some individuals experiencing unilateral or bilateral symptoms that radiate to the legs, rather than the classic symptoms of true claudication. The first symptoms of stenosis include episodes of low back pain. After a few months or years, this may progress to claudication. The pain may be radiating, following classic neural pathways. This occurs as the spinal nerves or spinal cord become increasingly trapped in a smaller space within the canal. It is difficult to tell whether pain in older adults is caused by reduced blood flow or narrowing, but tests can distinguish between the two. However, some patients may have both conditions. In people with lower extremity pain and back pain, lumbar stenosis is twice as likely to be the cause in those over 70 years of age, and less than half as likely in those under 60 years of age. Characteristics of the pain are also helpful in diagnosis. When discomfort does not occur while sitting, lumbar spinal stenosis is significantly more likely, about 7.4 times more likely. Other features that increase the likelihood of lumbar spinal stenosis include: symptoms improve when bending forward, pain that occurs in either the buttocks or legs, and the presence of neurogenic claudication. On the other hand, the absence of neurogenic claudication makes lumbar stenosis less likely to explain the pain. Nonsurgical treatments and laminectomy are the standard treatment for lumbar spinal stenosis, and conservative treatment is usually recommended. Individuals are generally advised to avoid stress on the lower back, especially during spinal extension. Physical therapy programs that strengthen the core and provide aerobic exercise may be recommended. There is no conclusive scientific evidence on whether conservative or surgical treatment is better for lumbar spinal stenosis. Evidence for the use of pharmacologic interventions in the treatment of lumbar spinal stenosis is weak. Injectable calcitonin, rather than intranasally, may be helpful for short-term pain relief. Epidural injections may also provide temporary pain relief, but there is no evidence of long-term benefit. Adding corticosteroids to these injections does not improve outcomes, and the use of epidural steroid injections is controversial and the evidence for their effectiveness is conflicting. Nonsteroidal anti-inflammatory drugs, muscle relaxants, and opioid analgesics are used to treat low back pain, but evidence of their effectiveness is limited. Surgery appears to be better if symptoms persist after 3–6 months of conservative treatment. Laminectomy is the most effective surgical treatment. Surgery improves 60–70% of cases where symptoms worsen despite conservative treatment. Another procedure used an interbody abduction device called X-Stop was less effective and more expensive when repairing multiple levels of the spine. Both surgeries are more expensive than medical treatment.