[Platybasia, basilar groove, odontoid process and kinking of the brainstem: a common etiology with idiopathic syringomyelia, scoliosis and Chiari malformations].

INTRODUCTION

A common aetiopathogenic theory for basilar groove (IMB), platybasia (PTB), odontoid retrocession (RTO), kinking of the brainstem (KTC) applied to idiopathic syringomyelia (SMI), idiopathic scoliosis (ESCID) and Arnold-Chiari malformation (ARCH) is presented. Confirmation is based on an abnormally low position of the conus medullaris (CMB) in the patients with SMI.

MATERIALS AND METHOD

292 patients with syringomyelia (SM), 231 with SMI were selected. Of these, 55 were chosen who had SMI and in whom the level of the conus medullaris (NCM) could be determined, together with the figures for SMI, IMB, PTB, RTO, KTC, ESCID and ARCH on cervical and lumbar MR. The position of the conus medullaris in 50 patients who did not have SM, ESCID nor ARCH on cervical and lumbar RM was determined.

RESULTS

32 patients had an increased basal angle (58.18%). There was an IMB in a quarter of the patients (25.45%). RTO was observed in half of the patients (47.27%). Just over one third presented a KTC. 6% of the control group had CM at the level of the body of L1, whilst 84.21% of the patients with SMI presented a partial or complete CM image at this level.

CONCLUSIONS

CMB in SMIU and its close relationship with IMB, PTB, RTO AND KTC and also with ESCID and ARCH make it likely that they share the same aetiopathogenic mechanism: an abnormal lack of synchronization of the growth of the neuro-axis and the neural canal (AACNN), causing a specific disorder which is seen as different syndromes.