SYMPTOMATIC POST-TRAUMATIC SYRINGOMYELIA: ARE THERE PREDICTIVE FACTORS ?

Abstract

Purpose: The incidence of postraumatic vertebromedullary syringomyelia is difficult to estimate but the most recent series have reported 28%. The purpose of this retrospective study was to search for risk factors of symptomatic posttraumatic syringomyelia (PTS) and to propose an adapted approach for early management.

Material and methods: Forty-six patients consulted for symptomatic PTS 14 years (range 9 months – 45 years) after their trauma. Half of the patients had initially undergone treatment (osteosynthesis in 74% and laminectomy in 70%). Physical signs, the Frankel score, measure of functional independence (MFI) at discovery of PTS were compared with findings early after trauma. Local kyphosis and residual canal stenosis were measured. The location, length, and extension of the syringomyelic cavity, presence of arachnoiditis, and freedom of the subarachnoid spaces were studied on magnetic resonance images. Intra-cystic and perimedullary fluid flow was also quantified.

Results: Gender, age, vertebral level, and degree of initial neurological deficit were not predictive of symptomatic PTS. Clinical signs of PTS were pain, paraesthesia, or supra-lesion motor deficit in two-thirds of the patients, bladder sphincter disorders or aggravation of sub-lesion residual motricity in the others. The MFIwas statistically decreased compared with the initial evaluation. Clinical signs were significantly correlated with intracavitary velometric measures. There was no correlation between clinical severity, time to development of PTS, initial treatment (surgery versus orthopaedic), and the kyphosis value or degree of stenosis. When residual kyphosis was greater than 35° or when canal narrowing was greater than 30%, the cavity was more extensive.

Discussion: It is important to search for PTS in subjects with a history of vertebromedullary injury who present changes in the clinical or functional presentation (aggravation of MFI) late after trauma. MRI velometry provides a better understanding of progression of postraumatic cystic myelopathy. The degree of kyphosis and canal stenosis appear to be predictive of lesion extension.

Conclusion: Initial correction of spinal deformations after trauma and recalibration of the spinal canal help prevent development and aggravation of PTS.