Acta Neurochir (2014) 156:1937–1946 DOI 10.1007/s00701-014-2155-0
CLINICAL ARTICLE - VASCULAR
Gamma knife radiosurgery for brainstem cavernous malformations: should a patient wait for the rebleed? Sung Ho Lee & Hyuk Jai Choi & Hee Sup Shin & Seok Keun Choi & In Ho Oh & Young Jin Lim
Received: 25 March 2014 / Accepted: 5 June 2014 / Published online: 27 June 2014 # Springer-Verlag Wien 2014
Abstract Background The effectiveness of stereotactic radiosurgery (SRS) for cavernous malformation (CM) has not been fully assessed. Consequently, observation is usually recommended when a bleeding CM is initially discovered. Recurrent bleeding occurs with CMs, and these repeat hemorrhages can result in additional morbidity. Methods From 1992 to 2011, 49 patients with brainstem CMs were treated with Gamma Knife radiosurgery (GKS). We classified patients into two groups: Group A (n=31), patients who underwent GKS for a CM following a single symptomatic bleed, and group B (n=18), patients who underwent GKS for a CM following two or more symptomatic bleeds. The mean marginal dose of radiation was 13.1 Gy (range 9.016.8 Gy): 12.8 Gy in group A and 13.7 Gy in group B. The mean follow-up period was 64.0 months (range 1-171 months). Results In group A, the annual hemorrhage rate (AHR) following GKS was 7.06 % within the first 2 years and 2.03 % after 2 years. In group B, four patients (22.2 %) developed new or worsening neurologic deterioration as a result of repeat hemorrhages. In group B, the AHR was 38.36 % prior to GKS, 9.84 % within the first two years, and 1.50 % after two years. There was no statistically significant difference in the AHRs at each follow-up period after GKS between the S. H. Lee : S. K. Choi : I. H. Oh : Y. J. Lim (*) Department of Neurosurgery, Kyung Hee University College of Medicine, 1 Hoegi-dongDongdaemun-gu Seoul 130-702, Korea e-mail:
[email protected] H. J. Choi Department of Neurosurgery, Chuncheon Sacred Heart Hospital, Hallym University College of Medicine, Chuncheon, Korea H. S. Shin Department of Neurosurgery, Kyung Hee University Hospital at Gangdong, Seoul, Korea
two groups. Adverse radiation effects (AREs) developed in a total of four patients (8.2 %); among them, one patient (2.0 %) developed a permanent case of diplopia. No mortality occurred in this series. Conclusion In this study, GKS was demonstrated to be a safe and effective alternative treatment for brain stem CMs that resulted in a reduction in the AHR. Consequently, we suggest that even CM patients who have suffered only a single bleed should not be contraindicated for SRS. Keywords Brainstem . Cavernous malformation . Gamma Knife surgery . Stereotactic radiosurgery . Annual hemorrhage rate
Introduction A 20-year-old debate on the utility and effectiveness of stereotactic radiosurgery (SRS) for cavernous malformation (CM) still remains unresolved [21, 26, 32]. Although complete surgical resection is the treatment of choice for most intracranial CMs in order to prevent recurrent bleeding, it usually carries a high risk of complication when the lesion is located in deep or eloquent areas like the brain stem [12, 24, 25, 34]. Since the rebleeding rate of a CM after the first hemorrhage tends to decline with time [4], some studies recommend patient observation rather than aggressive management when a lesion located in the brain stem bleeds for the first time [1, 8, 14]. Several current reports have suggested that SRS could be a good alternative treatment option for intracerebral CMs as a means of reducing the annual hemorrhage rate (AHR) with a relatively low risk of morbidity [10, 21, 25, 26, 28]. Rebleeding of CMs can result in additional morbidity, particularly considering the higher rebleeding rate of CMs located in the brain stem as compared with other locations [9, 30, 34].
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In the current study, we evaluated the efficacy of Gamma Knife surgery (GKS) for CMs following a single initial bleed.
Materials and methods Patient populations Between October 1992 and September 2011, GKS was performed on 54 patients with symptomatic CMs located in the brain stem (midbrain, pons, and medulla oblongata). The patients who underwent microsurgical resection prior to GKS or who were lost during the follow-up period were excluded. Ultimately, 49 patients with a solitary lesion were enrolled in this retrospective study (Table 1). The mean age of the patients was 43 years (range 7-71 years). Twenty-nine patients (59.2 %) were male. The pons was the predominant lesion location, found in 28 cases (57.1 %). Eleven lesions (22.4 %) were found in the midbrain, six lesions (12.2 %) in the medulla oblongata, and four lesions (8.2 %) in the pontomedullary junction (PMJ). Prior to undergoing GKS, recognized bleeding of CMs occurred once in 31 patients (63.3 %), twice in 17 patients (34.7 %), and three times in one patient (2.0 %). We classified patients into two groups; group A included patients with history of only a single symptomatic hemorrhage before GKS, and group B included the patients with a history of two or more symptomatic hemorrhages before GKS. The mean age was 41.1 years in group A and 46.3 years in group B. Pediatric cases (
