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

Background: 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.

Methods: 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.

Results: 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.

Conclusions: 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.