Gamma Knife surgery for clival epidural-osseous dural arteriovenous fistulas

Restricted access


Clival epidural-osseous dural arteriovenous fistula (DAVF) is often associated with a large nidus, multiple arterial feeders, and complex venous drainage. In this study the authors report the outcomes of clival epidural-osseous DAVFs treated using Gamma Knife surgery (GKS).


Thirteen patients with 13 clival epidural-osseous DAVFs were treated with GKS at the authors’ institution between 1993 and 2015. Patient age at the time of GKS ranged from 38 to 76 years (median 55 years). Eight DAVFs were classified as Cognard Type I, 4 as Type IIa, and 1 as Type IIa+b. The median treatment volume was 17.6 cm3 (range 6.2–40.3 cm3). The median prescribed margin dose was 16.5 Gy (range 15–18 Gy). Clinical and radiological follow-ups were performed at 6-month intervals. Patient outcomes after GKS were categorized as 1) complete improvement, 2) partial improvement, 3) stationary, and 4) progression.


All 13 patients demonstrated symptomatic improvement, and on catheter angiography 12 of the 13 patients had complete obliteration and 1 patient had partial obliteration. The median follow-up period was 26 months (range 14–186 months). The median latency period from GKS to obliteration was 21 months (range 8–186 months). There was no intracranial hemorrhage during the follow-up period, and no deaths occurred. Two adverse events were observed following treatment, and 2 patients required repeat GKS treatment with eventual complete obliteration.


Gamma Knife surgery offers a safe and effective primary or adjuvant treatment modality for complex clival epidural-osseous DAVFs. All patients in this case series demonstrated symptomatic improvement, and almost all patients attained complete obliteration.

ABBREVIATIONS CN = cranial nerve; DAVF = dural arteriovenous fistula; GKS = Gamma Knife surgery; MRA = MR angiography; PICA = posterior inferior cerebellar artery; TOF = time of flight; VA = vertebral artery.

Article Information

Correspondence Hsiu-Mei Wu, Department of Radiology, Taipei Veterans General Hospital, Taipei 11217, Taiwan. email:

INCLUDE WHEN CITING Published online June 16, 2017; DOI: 10.3171/2017.1.JNS161346.

Disclosures The authors report no conflict of interest concerning the materials or methods used in this study or the findings specified in this paper.

© AANS, except where prohibited by US copyright law.



  • View in gallery

    Typical clival epidural-osseous DAVF dose plan. All nidus contents were covered within the planned treatment volume, including neurovascular structures within the jugular foramen. The radiosurgical volume denoted by yellow (55% isodose line) was 11.7 ml, and the margin dose was 16 Gy. With the narrowed space, keeping the brainstem under 12 Gy was necessary to avoid adverse radiation effects. Green lines indicate 12 Gy and 15 Gy. Figure is available in color online only.

  • View in gallery

    Case 1. Images obtained in a 52-year-old woman with a right-sided Cognard Type I clival epidural-osseous DAVF. Axial TOF MRA images and VA and internal carotid artery injection cerebral angiograms, anteroposterior and lateral views, obtained in a patient treated with a margin dose and maximum dose of 16 and 29 Gy, respectively. The target volume was 11.7 cm3. A gradual decrease in abnormal flow was noted on follow-up MRA images. Cerebral angiograms demonstrated complete obliteration at 19 months (19M). DSA = digital subtraction angiography; ICA = internal carotid artery.





All Time Past Year Past 30 Days
Abstract Views 123 123 6
Full Text Views 172 172 1
PDF Downloads 175 175 4
EPUB Downloads 0 0 0


Google Scholar