gms | German Medical Science

Objective: The therapeutic and diagnostic significance of MRI in prone position in different diseases is very rarely described and still controversial. In this study we analyzed the relevance of this method especially in Tethered Spinal Cord (TSC) syndromes. As the diagnosis and the indication for surgical treatment in this complex group is often difficult we used an additional MRI in prone position and compared the results with conventional MRI images in supine position.

Method: Between 01/2011 and 12/2013, 40 cases with neurological symptoms suspicious for TSC were retrospectively reviewed. All of them were examined with a MRI in prone and supine position. The average age was 10,5 years (range 4 months – 40 years) involving 17 patients with a thick filum terminale, 15 patients with secondary tethering after operation of a spinal dysraphism, 3 patients with lipomyelomeningocele (LMMC) and 5 without pathologic MRI.

Results: MRI in prone position could confirm the diagnosis of TSC in 35 patients (87,5%) as the conus or filum terminale was attached to the dorsal dura and showed a persistent posterior displacement. 26 (76,2%) of these patients were operated and successfully untethered. On the other hand the preoperative MRI control in prone position could exclude a significant tethering in 5 patients. One year follow up was done in 14 of the 26 operated patients with the same MRI modalities which showed a significant better movement of the conus and/or the filum terminale in 8 (57,1%) patients.

Conclusions: MRI in prone position is an additional method to show differences in the elasticity of the conus medullaris. As it is a noninvasive method, we recommend using this modality to confirm or rule out the diagnosis especially in patients with an uncertain TSC syndrome. Although all of the operated patients had significant improvements of clinical symptoms, only 57,1% showed a better movement of the conus medullaris or filum terminale in the MRI follow ups. Establishing the diagnostic value of MRI in prone position in spinal dysraphism requires further prospective evaluation in a larger multicentric cohort of patients.