The words spinal stenosis have a Greek origin. The word “stenosis” means “choking.” Spinal, of course, means spine. So spinal stenosis is a choking (or narrowing) of the spine canal. While anything that narrows the spinal canal (e.g., a disc herniation) will create stenosis, conventionally when “spinal stenosis” is used as a diagnosis, it refers to a predominance of the stenosis originating from the posterior elements (e.g., facet joint arthropathy, buckled ligamentum flavum) although there is often an element of disc herniation contributing to the stenosis.

The anatomic finding of some degree of spinal stenosis is “ part of aging” in the sense that after the age of 65, just about everyone is going to have some degree of spinal stenosis on MRI [1, 2]. Of course, not everyone over the age of 65 has symptoms from their spinal stenosis. Indeed, most people do not. Even in patients with spinal stenosis and symptoms, there are typically other levels within that patient’s spine that reveal some amount of stenosis without symptomatology.

When spinal stenosis does cause symptoms, the symptoms do not generally occur because of a true compression of the spinal nerves but rather the reduced space in the spinal canal creates a greater propensity for the patient to develop inflammation around the nerve roots as a result of the stenosis and this leads to symptoms. In rare cases the nerves may become truly mechanically compressed in which case the symptoms are generally severe and progressive.

Common symptoms of spinal stenosis include lower back pain radiating into the legs. The symptoms are generally worse with standing and walking and relieved with sitting or bending forward. Other symptoms may include numbness and tingling in the legs. Patients may also complain of a lack of feeling steady on their feet. A common sign is something called the shopping cart sign. In this sign, a patient describes being unable to walk more than 5 min but then says that they can walk for a half hour with ease in the shopping center when they are bent over on the shopping cart. While it is often assumed by the patient that this is because they are leaning their weight onto the cart, it is in fact due to the fact that they are flexed forward while leaning on the shopping cart, which alleviates the pressure from their spinal nerves.

Consider the following patient. Charles is a 78-year-old male with a 5-year history of progressively worsening lower back pain radiating into the bilateral posterior and lateral thighs and lower legs. His legs feel heavy when he walks. He can walk about 10 min before he has to sit down. As soon as he sits down, the pain goes away. On physical examination, he has 4+/5 bilateral hip abductor strength and decreased sensation to light touch in the bilateral soles of the feet but is otherwise neurologically intact. He has pain and restricted movement with trunk extension and bilateral oblique extension.

Most spine specialists would agree that Charles probably has spinal stenosis causing bilateral lumbosacral radiculopathies. MRI of the lumbosacral spine would likely reveal moderate multilevel spinal stenosis. If vascular claudication is suspected then Dopplers may be obtained. An inexpensive way to differentiate vascular claudication from spinal stenosis symptoms is to have a patient walk and also use an exercise bicycle. If the patient has spinal stenosis causing his symptoms, then he should have the leg symptoms while walking but he should not have the leg symptoms when using a bicycle. This is because his is in a trunk flexed position while on the bicycle which takes the pressure off his nerves. If on the other hand the symptoms are due to vascular causes, then the symptoms should limit his ability to walk as well as to ride a bicycle. This is because in vascular claudication it is the demand for oxygen that causes the symptoms in the legs and so walking and bicycling both create that demand and the position of the patient’s trunk is immaterial.

Initial treatment for lumbar spinal stenosis typically involves physical therapy that focuses on lumbar stabilization and hip strengthening exercises and hip flexor and knee extensor stretching. Passive modalities are often used as well to reduce overlying myofascial pain and adhesions. If symptoms are not improving with physical therapy, or if the symptoms make it difficult to participate with physical therapy, then an epidural steroid injection may be helpful. It should be emphasized that an epidural steroid injection does not “fix” the underlying stenosis. An epidural steroid injection is also not a “Band-Aid” in that it is not a painkiller. Rather, an epidural steroid injection helps reduce the swelling and inflammation from around an inflamed nerve root. When an epidural steroid injection is able to reduce this swelling and remove the symptoms, it should be coupled to physical therapy exercises in order to maximize the biomechanics and help reduce the pressure from the spinal canal so that ideally the symptoms do not recur [4].

Epidural steroid injections are more effective for foraminal stenosis than for central stenosis. For a more complete discussion of epidural steroid injections, see the previous chapters on lumbosacral radiculopathy and discogenic lower back pain. For multiple pathologies, long-term outcomes rest more in participation and compliance with therapeutic exercise regimens and postural and ergonomic adjustments than with lone injections. However, this is particularly true when considering spinal stenosis. Studies have repeatedly shown that epidural steroid injections for spinal stenosis offer good short-term relief but inconsistent long-term outcomes after 6 months or a year [5, 6]. It is also important to note that studies have also shown poor compliance with therapeutic exercises after 6 months to a year. The sum results of these datum is the importance that the physician articulates the necessity of learning and participating in a consistent therapeutic exercise program as well as improved ergonomic and postural habits and possibly activity modification in order to achieve the desired long-term results.