title: Stereotactic radiosurgery for Spetzler-Martin Grade III arteriovenous malformations: an international multicenter study.
abstract: OBJECTIVE Because of the angioarchitectural diversity of Spetzler-Martin (SM) Grade III arteriovenous malformations (AVMs), the management of these lesions is incompletely defined. The aims of this multicenter, retrospective cohort study were to evaluate the outcomes after stereotactic radiosurgery (SRS) for SM Grade III AVMs and to determine the factors predicting these outcomes. METHODS The authors analyzed and pooled data from patients with SM Grade III AVMs treated with SRS at 8 institutions participating in the International Gamma Knife Research Foundation. Patients with these AVMs and a minimum follow-up length of 12 months were included in the study cohort. An optimal outcome was defined as AVM obliteration, no post-SRS hemorrhage, and no permanently symptomatic radiation-induced changes (RICs). Data were analyzed by univariate and multivariate regression analyses. RESULTS The SM Grade III AVM cohort comprised 891 patients with a mean age of 34 years at the time of SRS. The mean nidus volume, radiosurgical margin dose, and follow-up length were 4.5 cm3, 20 Gy, and 89 months, respectively. The actuarial obliteration rates at 5 and 10 years were 63% and 78%, respectively. The annual postradiosurgery hemorrhage rate was 1.2%. Symptomatic and permanent RICs were observed in 11% and 4% of the patients, respectively. Optimal outcome was achieved in 56% of the patients and was significantly more frequent in cases of unruptured AVMs (OR 2.3, p < 0.001). The lack of a previous hemorrhage (p = 0.037), absence of previous AVM embolization (p = 0.002), smaller nidus volume (p = 0.014), absence of AVM-associated arterial aneurysms (p = 0.023), and higher margin dose (p < 0.001) were statistically significant independent predictors of optimal outcome in a multivariate analysis. CONCLUSIONS Stereotactic radiosurgery provided better outcomes for patients with small, unruptured SM Grade III AVMs than for large or ruptured SM Grade III nidi. A prospective trial or registry that facilitates a comparison of SRS with conservative AVM management might further clarify the authors' observations for these often high-risk AVMs.
authors.affiliation: Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia.
authors.forename: Dale
authors.initials: D
authors.lastname: Ding
authors.affiliation: Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia.
authors.forename: Robert M
authors.initials: RM
authors.lastname: Starke
authors.affiliation: Department of Neurological Surgery, University of Pittsburgh, and.
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Kano
authors.affiliation: Department of Neurosurgery, University of Pennsylvania, Philadelphia, Pennsylvania.
authors.forename: John Y K
authors.initials: JY
authors.lastname: Lee
authors.affiliation: Division of Neurosurgery, University of Sherbrooke, Centre de recherché du CHUS, Sherbrooke, Quebec, Canada.
authors.forename: David
authors.initials: D
authors.lastname: Mathieu
authors.affiliation: Department of Neurosurgery, University of Pennsylvania, Philadelphia, Pennsylvania.
authors.forename: John
authors.initials: J
authors.lastname: Pierce
authors.affiliation: Department of Neurosurgery, NYU Langone Medical Center, New York, New York.
authors.forename: Paul P
authors.initials: PP
authors.lastname: Huang
authors.affiliation: Section of Neurological Surgery, University of Puerto Rico, San Juan, Puerto Rico.
authors.forename: Caleb
authors.initials: C
authors.lastname: Feliciano
authors.affiliation: Section of Neurological Surgery, University of Puerto Rico, San Juan, Puerto Rico.
authors.forename: Rafael
authors.initials: R
authors.lastname: Rodriguez-Mercado
authors.affiliation: Section of Neurological Surgery, University of Puerto Rico, San Juan, Puerto Rico.
authors.forename: Luis
authors.initials: L
authors.lastname: Almodovar
authors.affiliation: Beaumont Health System, Royal Oak, Michigan; and.
authors.forename: Inga S
authors.initials: IS
authors.lastname: Grills
authors.affiliation: Department of Neurosurgery, Cleveland Clinic Foundation, Cleveland, Ohio.
authors.forename: Danilo
authors.initials: D
authors.lastname: Silva
authors.affiliation: Department of Neurosurgery, Cleveland Clinic Foundation, Cleveland, Ohio.
authors.forename: Mahmoud
authors.initials: M
authors.lastname: Abbassy
authors.affiliation: Department of Neurosurgery, Cleveland Clinic Foundation, Cleveland, Ohio.
authors.forename: Symeon
authors.initials: S
authors.lastname: Missios
authors.affiliation: Department of Neurosurgery, NYU Langone Medical Center, New York, New York.
authors.forename: Douglas
authors.initials: D
authors.lastname: Kondziolka
authors.affiliation: Department of Neurosurgery, Cleveland Clinic Foundation, Cleveland, Ohio.
authors.forename: Gene H
authors.initials: GH
authors.lastname: Barnett
authors.affiliation: Department of Neurological Surgery, University of Pittsburgh, and.
authors.forename: L Dade
authors.initials: LD
authors.lastname: Lunsford
authors.affiliation: Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia.
authors.forename: Jason P
authors.initials: JP
authors.lastname: Sheehan
mesh_terms: D000328:Adult; D002543:Cerebral Hemorrhage / Q000175:diagnosis / Q000532:radiotherapy; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D002538:Intracranial Arteriovenous Malformations / Q000175:diagnosis / Q000532:radiotherapy*; D008297:Male; D016634:Radiosurgery; D012189:Retrospective Studies; D012422:Rupture, Spontaneous / Q000175:diagnosis / Q000532:radiotherapy; D012720:Severity of Illness Index; D016896:Treatment Outcome
keywords: ARUBA = A Randomized Trial of Unruptured Brain AVMs; AVM = arteriovenous malformation; EBRT = external-beam radiation therapy; Gamma Knife; RBAS = radiosurgery-based AVM score; RIC = radiation-induced change; SAIVM = Scottish Audit of Intracranial Vascular Malformations; SM = Spetzler-Martin; SRS = stereotactic radiosurgery; Spetzler-Martin Grade III; VRAS = Virginia Radiosurgery AVM Scale; intracranial arteriovenous malformation; intracranial hemorrhages; radiosurgery; stereotactic radiosurgery; vascular disorders; vascular malformations