title: Delayed cyst formations and/or expanding hematomas developing after Gamma Knife surgery for cerebral arteriovenous malformations.
abstract: The authors retrospectively analyzed cyst formations and expanding haematomas (EHs) that developed after Gamma Knife surgery (GKS) for arteriovenous malformations (AVMs), and evaluated the treatment results of these lesions. Cyst formations and/or EHs which developed after GKS for AVMs were identified in 20 patients (5.0%) out of 404 patients who underwent this procedure. There were nine patients with cyst formations, two with EHs and nine with cyst formations with EHs. These lesions developed between 36 and 192months (median 99months) after GKS. The median nidus volume was 4.7ml (range, 1.8-14.2ml) and the median prescribed margin dose was 20Gy (range, 15-23Gy). The multivariate analysis showed no correlation between the appearance of cyst formations and/or EHs and the patients' age, sex, nidus volume, margin dose, repeated GKS, nidus obliteration, pre-GKS embolization and prior hemorrhage. Surgical treatment was required in nine patients. Eight patients had total removal of the angiomatous lesions (EHs or nodular lesions that were detected as enhancement part on MRI) via a craniotomy and one had a cyst aspiration. There was no recurrence of the lesions in all the patients that underwent a craniotomy. In the patient treated with a cyst aspiration, regrowth of the cyst formation occurred. Surgical treatment should be considered for symptomatic lesions and we recommend total removal of the angiomatous lesions to achieve a complete cure.
authors.affiliation: Department of Neurosurgery, Osaka City General Hospital, 2-13-22 Miyakojima-hondori Miyakojima-ku, Osaka 534-0021, Japan. Electronic address: hikkinakajima@yahoo.co.jp.
authors.forename: Hideki
authors.initials: H
authors.lastname: Nakajima
authors.affiliation: Department of Neurosurgery, Osaka City University Graduate School of Medicine, Osaka, Japan.
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Yamanaka
authors.affiliation: Department of Neurosurgery, Osaka City General Hospital, 2-13-22 Miyakojima-hondori Miyakojima-ku, Osaka 534-0021, Japan.
authors.forename: Kenichi
authors.initials: K
authors.lastname: Ishibashi
authors.affiliation: Department of Neurosurgery, Osaka City General Hospital, 2-13-22 Miyakojima-hondori Miyakojima-ku, Osaka 534-0021, Japan.
authors.forename: Yoshiyasu
authors.initials: Y
authors.lastname: Iwai
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D020863:Central Nervous System Cysts / Q000000981:diagnostic imaging / Q000473:pathology*; D002648:Child; D003399:Craniotomy / Q000009:adverse effects; D004621:Embolization, Therapeutic; D005260:Female; D006406:Hematoma / Q000000981:diagnostic imaging / Q000473:pathology*; D006801:Humans; D002538:Intracranial Arteriovenous Malformations / Q000150:complications / Q000601:surgery*; D008279:Magnetic Resonance Imaging; D008297:Male; D000072662:Margins of Excision; D008875:Middle Aged; D011183:Postoperative Complications / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000628:therapy; D016634:Radiosurgery / Q000009:adverse effects*; D012189:Retrospective Studies; D013396:Suction; D055815:Young Adult
keywords: Cerebral arteriovenous malformation; Cyst formation; Expanding hematoma; Gamma Knife surgery