Are herniated cerebellar tonsils the main culprit of chiari malformation type i symptoms? brainstem compression hypothesis seems to be re-elucidated and revised

Abstract

ABSTRACTneurological deficits including motor weakness, sensory disturbances and urinary or stool incontinence (2). The demonstration of TCS is based on the magnetic resonance imaging (MRI) findings such as thick filum terminale (>2 mm diameter), a low-positioned conus medullaris, posterior displacement of the conus medullaris and filum terminale, and a wide lumbar and sacral subarachnoid space (18). However, if there is no anatomical evidence of low-lying conus on lumbar MRI and the filum terminale has normal thickness, it is difficult to diagnose tethered spinal cord. In such cases, after a somatosensory evoked potentials study, sectioning of filum terminale in case of a tethered cord diagnosis often helps resolve the symptoms but the indications for cutting the filum in this context are still controversial (6,14).

Chiari I Malformation and Spinal Cord Ischemia in a Cadaver

“…Animal models with underdeveloped posterior cranial fossae support this theory [ 2 ]. The spinal cord tethering theory states that tension forces herniation of the hindbrain; however, this does not successfully explain other presentations of CIM [ 4 ]. The hydrodynamic theory is based on the craniospinal pressure gradient and dictates that pulsatile pressure from the supratentorial region causes cerebellar herniation and cerebrospinal fluid flow reversal, resulting in syringomyelia.…”

Sectioning of the Filum Terminale in Patients with Chiari Malformation Type 1 Associated with Occult Tethered Cord Syndrome: Literature Review

“…Selcuki et al 46 presented 7 patients diagnosed with CM1 and TCS and who underwent SFT. As a diagnostic criterion for CM1, the clinical and radiological findings of tonsillar herniation were used, and for TCS, the clinical findings and the position of the conus medullaris below L2 and a fatty or thickened filum were used.…”