Lumbar Spinal Stenosis
Overview
Lumbar spinal stenosis is a degenerative disease where the spinal canal in the lower back becomes narrow. This narrowing is usually caused by a mix of bone and soft tissue changes, such as facet joint overgrowth, spondylolisthesis, disc herniation, and thickening or folding of the ligamentum flavum. These changes reduce the space for the spinal nerves, which can compress the cauda equina or nerve roots.
The condition most often affects the L4–L5 level and is one of the most common reasons for lumbar spine surgery in patients over 65 years old. Its frequency increases with age, and it is seen slightly more in men than in women. Risk factors include high body mass index, congenital spinal features such as short pedicles, and other degenerative spinal disorders.
Diagnosis is mainly made with MRI, which gives detailed information about the central canal, lateral recesses, and neural foramina.
Clinical Presentation
Patients with lumbar spinal stenosis usually report low back pain that can spread to the buttocks and legs. At first, the pain may be on one side, but it often becomes bilateral as the disease progresses. The key symptom is neurogenic claudication—leg pain, heaviness, or weakness that starts with walking or standing for a long time and improves with sitting or bending forward. This happens because forward flexion opens the spinal canal and foramina.
Other typical findings include:
● Pain relief when leaning forward, for example on a shopping cart.
● Negative straight leg raise test in most patients, which helps distinguish it from disc herniation.
● Normal peripheral pulses, which helps separate it from vascular claudication.
● Weakness, numbness, or bladder problems in more advanced cases.
● Symptoms usually disappear while sitting, but return with walking or lumbar extension.
Imaging
Plain radiographs can show degenerative changes, scoliosis, or spondylolisthesis. Dynamic flexion–extension radiographs provide valuable information in the assessment of spinal instability. CT myelography is only used when MRI is not possible or when MRI results are unclear.
MRI is the preferred imaging method for lumbar spinal stenosis. It shows both the severity and the exact location of narrowing. Central canal stenosis is usually defined as a cross-sectional area smaller than 100 mm² or an anteroposterior diameter less than 10 mm. Lateral recess and foraminal stenosis are seen when the perineural fat is lost and the nerve root is directly compressed.
Treatment
The first approach to lumbar spinal stenosis is nonoperative management. This includes nonsteroidal anti-inflammatory drugs (NSAIDs), structured physical therapy with flexion-based exercises, weight reduction, and lumbosacral bracing. Epidural or transforaminal steroid injections can provide short- to medium-term relief and may delay surgery.
Patient education is a key part of treatment. Patients should avoid long standing or walking uphill, pace their daily activities, and use supportive devices when necessary. Regular follow-up is important to detect any progression to neurological problems.
Surgical Indications
Surgery is considered when symptoms remain severe after 3–6 months of nonoperative treatment, when neurological deficits progress (such as muscle weakness or bladder/bowel problems), or when neurogenic claudication severely limits daily activities.
The standard operation is wide pedicle-to-pedicle decompression. This involves removing the thickened ligamentum flavum and part of the medial facet joints to create more space in the spinal canal. If instability is present, for example in degenerative spondylolisthesis, decompression is combined with instrumented fusion. To lower the risk of postoperative instability, more than 50% of each facet joint is preserved whenever possible.
Prognosis
Surgery usually gives better pain relief and functional improvement than nonoperative treatment, especially in patients with severe neurogenic claudication. Still, recurrence may happen at nearby spinal levels because degenerative changes continue with aging.
The long-term outcome depends on the patient’s other health problems, their functional status before surgery, and the amount of decompression performed. Careful patient selection and follow-up are essential to maintain good results.
Differential Diagnosis
Several conditions can mimic lumbar spinal stenosis and should be considered:
● Vascular claudication – Symptoms get worse with uphill walking or cycling and do not improve with spinal flexion. It is often linked to reduced peripheral pulses.
● Hip osteoarthritis / Hip–spine syndrome – Hip disease can cause pain that overlaps with lumbar stenosis. In cases where both conditions exist, diagnostic hip injections may help identify the main pain source.
● Peripheral neuropathies – Nerve disorders in the legs can produce similar symptoms but are not related to spinal canal narrowing.
References
1- Katz JN, Harris MB. Clinical practice. Lumbar spinal stenosis. N Engl J Med. 2008 Feb 21;358(8):818-25. doi: 10.1056/NEJMcp0708097.
2- Zaina F, Tomkins-Lane C, Carragee E, Negrini S. Surgical versus non-surgical treatment for lumbar spinal stenosis. Cochrane Database Syst Rev. 2016 Jan 29;2016(1):CD010264. doi: 10.1002/14651858.CD010264.pub2.
3- Lurie JD, Tosteson TD, Tosteson A, Abdu WA, Zhao W, Morgan TS, Weinstein JN. Long-term outcomes of lumbar spinal stenosis: eight-year results of the Spine Patient Outcomes Research Trial (SPORT). Spine (Phila Pa 1976). 2015 Jan 15;40(2):63-76. doi: 10.1097/BRS.0000000000000731.