Degenerative spondylolisthesis is a condition in the spine where one vertebral body slips or slides forward over another. The condition generally occurs in patients older than 50 years of age, and women are more commonly affected than men. The condition is 8 times more likely to occur in women due to increased ligamentous laxity. The most common affected level is L4-L5. Presenting symptoms are similar to those of spinal stenosis. These may include chronic back pain with frequent lower extremity radiculopathy. Neurogenic claudication is also common, which includes symptoms of pain in the buttocks and thigh while standing or walking. Flexing the back forward often relieves symptoms, which is often referred to as the shopping cart sign.1
Two main types of spondylolisthesis occur in adults: degenerative and isthmic or spondylolysis. Instability with isthmic spondylolisthesis is caused by a defect in the pars interarticularis (spondylolysis). In the degenerative type, the cascade of instability involves disc degeneration and narrowing of the disc space, buckling of the ligamentum flavum, and facet degeneration. Laxity of supporting ligaments further increases instability. The Meyerding classification system is commonly used to describe the severity of the slip. Grade 1 is less than 25% slip, grade 2 is 25% to 50% slip, grade 3 is 50% to 75% slip, and grade 4 75% to 100% slip. Grade 1 may progress in as many as 30% of patients but rarely progresses past a grade 2 slip. Isthmic spondylolisthesis more commonly progresses past grade 2. 1,2
References
- Majid K, Fischgrund JS. Degenerative lumbar spondylolisthesis: trends in management. J Am Acad Orthop Sur. 2008;16(4):208-215.
- Moore D. Degenerative spondylolisthesis. Orthobullets web site. http://www.orthobullets.com/spine/2039/degenerative-spondylolisthesis. Updated June 25, 2016. Accessed July 19, 2016.
