Association Between Symptomatic Giant Sacral Meningeal Diverticulum and Spinal Cord Tethering With Thickened Lipomatous Filum

Study Design. A review of cases where symptomatic sacral meningeal diverticula, as known as, sacral meningoceles, were treated. Objective. To determine whether there is an association between symptomatic sacral meningeal diverticulum and spinal cord tethering with a thickened fatty filum. Summary of Background Data. In 2008, the primary author reported on the unusual case of a giant sacral meningeal diverticulum containing a tethering fatty filum. This led the author to be alert to the presence of spinal cord tethering in future cases involving symptomatic meningeal diverticula. Since the time of the initial report, 49 patients with meningeal diverticula have subsequently undergone surgical treatment and not infrequently spinal cord tethering was also found. The opportunity, therefore, presented itself to determine to what degree the two pathologies were associated. Methods. We reviewed the intraoperative findings, preoperative imaging, and basic epidemiologic data from 50 consecutively treated patients with symptomatic sacral meningeal diverticula. Results. Of the 50 patients, 14 (28%) were found to have associated spinal cord tethering with a thickened fatty filum. All 14 had a thickened fatty filum identifiable at surgery. Of these, 14 had evidence of spinal cord tethering on preoperative imaging studies, including 11 with the conus at the level of L2 or below, and 13 with a fatty filum seen on magnetic resonance images. Conclusion. The association between symptomatic sacral meningeal diverticula is more than incidental and is probably reflective of a common congenital etiology. Treatment of symptomatic meningeal diverticula should include a careful search for evidence of spinal cord tethering with a thickened fatty filum.