Management of Tight Filum Terminale Syndrome With Special Emphasis on Normal Level Conus Medullaris (NLCM)

BACKGROUND Tethered cord syndrome is classically defined as having the tip of the conus medullaris below the body of L2, instead of at the normal L1-2 disc space level. The syndrome presents most commonly with urinary incontinence. In a patient with urinary incontinence and a lowlying conus medullaris, tethered cord syndrome can be diagnosed without difficulty. However, in a patient with urinary incontinence and a hyperreflexive type of neurogenic bladder, in whom the conus medullaris is found to be at the normal level on magnetic resonance imaging, diagnosing a tethered cord can be challenging. We hypothesized that patients with hyperreflexive neurogenic bladders have a neurologic basis for their bladder dysfunction, probably secondary to tethering by a tight filum terminale, despite having a normally positioned conus medullaris.