P45. Radiological features of slip progression in adult patients with isthmic spondylolisthesis

Abstract

BACKGROUND CONTEXT Lumbar spondylolysis is generally recognized as a stress fracture of pars interarticularis occurring in childhood and adolescence. Non-union after pars fracture in the spinal motion segment may lead to isthmic spondylolisthesis. Various factors such as disc degeneration and sagittal radiological parameters contributing to slip progression in adult isthmic spondylolisthesis have been discussed. In the relationship between L5 isthmic spondylolisthesis and deformities of the sacral table, it was reported that the mechanism of vertebral slippage was different between immature and mature spine in animal studies. There are two types of isthmic spondylolisthesis which occur before and after skeletal maturity: adolescent slip with sacral deformities and adult slip without sacral deformities. However, in these two types of isthmic spondylolisthesis, there are no reports that have clarified whether there is a difference in the slip progression radiologically. PURPOSE Purpose of this study is to clarify the predictive risk factors contributing to progression of vertebral slippage in adults diagnosed with isthmic spondylolisthesis and treated conservatively. STUDY DESIGN/SETTING This is a retrospective study using 29 adult patients with isthmic spondylolisthesis. PATIENT SAMPLE Patients who were 20 to 59 years old and diagnosed with isthmic spondylolisthesis by ICD-9 and ICD-10 between 2007 and 2017 were included in this study through a Northwestern Medicine Enterprise Data Warehouse search. Patients who were diagnosed with dysplastic, traumatic, degenerative or pathologic spondylolisthesis, patients who have lumbar scoliosis, patients who have past medical history of spine surgery were excluded. OUTCOME MEASURES Slip progression and slip progression percent during follow-up. METHODS We evaluated their plain radiographs of the lumbar spine which were followed up for more than 3 years and analyzed factors affected the slip progression. RESULTS Patients’ mean age was 41.6 (± 7.9) years old. The follow-up period was 68.6 (± 20.8) months. Slip and slip% were 6.7 (± 4.1) mm, 15.5 (± 10.2) % at initial X-ray, and 10.0 (± 4.6) mm, 22.7 (± 10.6) % at final X-ray respectively. All of them progressed anterior slip during the follow-up period (P CONCLUSIONS All patients who were followed-up conservatively progressed anterior slip in this study cohort. However, the degree of their slip was not correlated with the sacral deformity or other factors described in the previous reports compared to normal group. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.