Late deterioration of neurologic function in patients surgically treated for spinal dural arteriovenous fistulas

A limited number of reports on the long-term neurologic outcome of patients with SDAVFs treated by surgery and/or embolization are available in the literature. The aim of our study is to neurologically evaluate these patients at 2 different follow-up stages, after surgery, to demonstrate a possible late neurologic deterioration after an initial improvement.

Between January 1987 and May 2002, 29 patients with SDAVFs were operated on at the Verona Department of Neurosurgery. In this group we retrospectively identified 16 patients who had 2 different clinical follow-ups, at a mean of 4.5 and 9.2 years, respectively. We compared their neurologic status using the ALS. All these data were obtained from clinical charts and phone interviews.

The epidemiologic, clinical, and radiologic features of our group of patients are very similar to those previously described in the literature. Comparing the global clinical status between the 2 different follow-up stages, we observed a late deterioration in 8 cases (50%). A worsening of the mean G and M values of the ALS was also noted. Spinal angiography and contrast-enhanced MRI did not show any signs of recurrence of the fistula.

Our study confirms the possible occurrence of a late clinical deterioration in as many as 50% of patients surgically treated for a SDAVF. We deem that the main pathophysiologic mechanism underlining this phenomenon is a gradual and irreversible decline in spinal function related to those hemodynamic modifications induced by the fistula and to the persistence of a state of anatomofunctional deficiency of the spinal venous drainage.