Long Term Follow-up of Lumbar Spine Annular Fissures

Background and Purpose: Annular fissures are common in the lumbar spine; their natural history is not well-known. They typically are bright on T2W and show linear enhancement. We hypothesized that Lumbar Annular Fissures (LAF) rarely resolve over time and their imaging features are static. Materials and Methods: From 2011 to 2021, we evaluated patients who had more than one lumbar spine MR. We recorded LAF imaging features on T1W, T2W, and post-contrast sequences and the evolution of those findings over time. We also inspected the evolution of concomitant disc pathology. Finally, we reviewed the radiologic reports to see if LAFs were mentioned. Results: Of the 441 included patients, 238 (54.0%) had a LAF. Of these, 123/238 (51.7%) had more than one LAF (total 436 LAFs). 433 (99.3%) LAFs were bright on T2W; 3 LAFs enhanced but were not bright on T2W. In follow up, (mean 621 days, SD 951 days), 145/436 (33.3%) LAFs changed in T2W signal intensity; 62.8% showed less hyperintensity on T2W, 7 resolved completely. Of 65 gadolinium-enhanced cases, 53 (81.5%) LAFs enhanced; that enhancement persisted in 85.4%. Bulges or herniations coexisted with LAFs in 388/436 (89.0%). With changes in signal intensity and gadolinium enhancement, the bulge/herniation often evolved. 15.8% of LAFs were reported. Conclusion: LAFs are prevalent (54.0%) but are under-reported. The vast majority are bright on T2W but that hyperintensity may change over time. Most LAFs enhance and do so persistently. Disk bulges and herniations coexist in 89% of cases and evolve with the LAFs. Clinical Relevance: The stability of T2 hyperintensity and gadolinium enhancement of LAFs over time implies that the age of the AF cannot be inferred unless it is newly appearing on a current study.