Stereotactic Radiosurgery for the Treatment of Low-Flow Carotid-Cavernous Fistulae: Results in a Series of 25 Cases

Abstract

25 patients with low-flow carotid-cavernous fistula (CCF) underwent radiosurgery between 1977 and 1992. 22 had spontaneous low flow fistulae and 3 traumatic high flow fistulae which had been previously treated with internal carotid trapping. The mean preoperative symptomatic period was 12.2 months (4–24 months). Fistulae were classified according to Barrow''s classification. Type T was added for traumatic, high-flow fistulae with flow reduction after internal carotid trapping. 11 cases were of type B, 4 of type C, 7 of type D and 3 of type T. The target point for radiosurgry was calculated from selective internal or external carotid angiograms. Stereotaffi;lradiosurgery was performed with a cobalt source, with 5- to 10-mm collimators. A total dose of 30–40 Gy was delivered in all cases, except 1 posttraumatic case in which the dose was 20 Gy. The follow-up period ranged between 14 years and 15 months (mean: 49.76 months). 20 of the 22 low flow fistulae (90.9%) completely closed in a mean period of 7.5 months (range: 2–20 months) after radiosurgery. Improvement of the symptoms began at a mean period of 2.37 months (range: 0.5–14 months). There were no recurrences, the follow-up period ranging between 14 years and 15 months. 100% of type B CCF closed after a mean period of 5.9 months, 75% of type C closed after a mean period of 12.66 months, and 85.7% of cases of type D closed after a mean period of 8.16 months. Only one of the three traumatic fistulae (type T) was cured 6 months after radiosurgery, while there was no significant change in the other two cases of type T fistulae. There was no untoward effect attributable to irradiation in the whole series. The authors conclude that because of its relative safety and efficacy this technique makes it the treatment of choice for low-flow CCF, while intravascular embolization maintains its indications for the high-flow ones.

Carotid-cavernous fistulas

“…Barcia-Salorio et al 3 reported complete or near-complete reversal of the neuroophthalmological symptoms associated with indirect CCFs in 91.6% of patients with spontaneous, low-flow lesions treated with radiosurgery. However, in patients presenting with previously treated direct CCFs, radiosurgery was effective in only 2 of 5 patients.…”

“…Other small series of patients with indirect CCFs have shown long-term obliteration of the fistula after treatment with radiosurgery in 75%-100% of patients. 3,17,28,53,64 Radiosurgery should not be used in emergency cases, as there is a latency of several months to years before complete obliteration of the CCF is accomplished. …”

Cavernous sinus fistulas: Carotid cavernous fistulas and dural arteriovenous malformations

“…Several series have reported success rates in 59% to 95% of patients using these techniques. Recalcitrant cases have been controlled with carotid ligation and radiosurgery [24,26].…”

“…Barcia-Salorio et al [26] reported their experience with stereotactic radiosurgery in 25 patients with low-flow fistulae; 11 cases were type B, four were type C, seven were type D and three were previously treated direct CCFs. Patients had 30 to 40 cGy delivered to the fistulae and 91% were found to be closed within 7 months.…”

Treatment of Carotid Cavernous Fistulas

“…It has been used to treat indirect CCFs. In selected small series of patients with indirect CCFs, the treatment results have been good, with cure rates of 75-100% [49,50]. There are no reports in the literature of cure for direct CCFs.…”