RESUMEN
An analysis of 1554 consecutive cases of patients requiring radiographic evaluation of the lumbosacral spine to diagnose the cause of low back pain of varying shows that 171 patients [11%] had spondylolisthesis. The three major types consisted of: dysplastic [congenital], isthmic [spondylolytic], and degenerative. The most common was spondylolytic [61%], followed by the dysplastic [23%], and then degenerative [14%]. Spondylolsis, with or without spondylolisthesis, occurred in 136 patients [i.e., 9% of patients who underwent radiography for low back pain]. Patients of all ages were affected by both the dysplastic and spondylolytic type, with a peak incidence between 20 and 40 years of age. The degenerative variety is largely a disease of women over 40 years of age. No distinct predisposing factors, such as exercise, occupation, or family history, were elected. However, in the degenerative variety, a sedentary lifestyle involving prolonged sitting could be a causative factor. The discovery of spondylolisthesis does not necessarily incriminate the cause. More detailed evaluation with myelography and computed tomographic or magnetic resonance imaging is mandatory in cases in which there is unrelenting pain