Radiosurgery versus observation for brainstem cavernous malformations: a 5-year multicentre cohort study.

The role of radiosurgery in preventing haemorrhage in brainstem cavernous malformations remains a subject of debate. This study aims to evaluate whether radiosurgery provides a protective benefit against haemorrhage in these patients. This multicentre, prospective observational study was conducted in 17 centres and enrolled eligible patients with brainstem cavernous malformations consecutively. Data collected included clinical baseline information, radiosurgery planning details, periodic follow-up evaluations, and any adverse radiation effects. The primary outcome of the study was the incidence of first prospective haemorrhage, while the secondary outcome was the development of new or worsening neurological dysfunctions. The impact of radiosurgery was assessed using multivariate Cox regression analysis. From March 2016 to August 2018, the study enrolled 377 patients: 280 in the observation group receiving standard care alone and 97 in the radiosurgery group receiving both radiosurgery and standard care. The overall cohort consisted of 173 females (45.9%) with a mean age of 40.5 years (range, 18-68 years), and there were no significant differences in baseline characteristics between the two groups. After a median follow-up period of 70 months, haemorrhage occurred in 25.0% (n = 70) of patients in the observation group and 10.3% (n = 10) of patients in the radiosurgery group. Multivariate Cox regression analysis identified radiosurgery as an independent protective factor against haemorrhage (hazard ratio 0.379, 95% confidence interval 0.195-0.738, P = 0.004). Following 1:2 propensity score matching, the incidence of prospective haemorrhage were 24.9% (45/181) in the observation group compared to 10.3% (10/97) in the radiosurgery group (hazard ratio 0.379, 95% confidence interval 0.190-0.755, P = 0.006). Adverse radiation effects were observed in 12 patients (12.4%), with none were permanent. Additionally, new or worsening neurological dysfunctions were significantly more common in the observation group (28.9%) compared to the radiosurgery group (16.5%) (P = 0.016). These results suggest that radiosurgery is associated with a low rate of haemorrhage in patients with brainstem cavernous malformations and could provide a benefit in selected patients. However, further research is required to confirm these findings.

Hemorrhagic Outcome of Brainstem Cavernous Malformations following Radiosurgery: Dose-Response Relationship.

INTRODUCTION: This study aimed to assess the impact of gamma knife radiosurgery on brainstem cavernous malformations (CMs). METHODS: A total of 85 patients (35 females; median age 41.0 years) who underwent gamma knife radiosurgery for brainstem CMs at our institute between 2006 and 2015 were enrolled in a prospective clinical observation trial. Risk factors for hemorrhagic outcomes were evaluated, and outcomes were compared across different margin doses. RESULTS: The pre-radiosurgery annual hemorrhage rate (AHR) was 32.3% (44 hemorrhages during 136.2 patient-years). The median planning target volume was 1.292 cc. The median margin and maximum doses were 15.0 and 29.2 Gy, respectively, with a median isodose line of 50.0%. The post-radiosurgery AHR was 2.7% (21 hemorrhages during 769.9 patient-years), with a rate of 5.5% within the first 2 years and 2.0% thereafter. The post-radiosurgery AHR for patients with margin doses of ≤13.0 Gy (n = 15), 14.0-15.0 Gy (n = 50), and ≥16.0 Gy (n = 20) was 5.4, 2.7, and 0.6%, respectively. Correspondingly, transient adverse radiation effects were observed in 6.7 (1/15), 10.0 (5/50), and 30.0% (6/20) of cases, respectively. An increased margin dose per 1 Gy (hazard ratio: 0.530, 95% CI: 0.341-0.826, p = 0.005) was identified as an independent protective factor against post-radiosurgery hemorrhage. Margin doses of ≥16.0 Gy were associated with improved hemorrhagic outcomes (hazard ratio: 0.343, 95% confidence interval [CI]: 0.157-0.749, p = 0.007), but an increased risk of adverse radiation effects (odds ratio: 3.006, 95% CI: 1.041-8.677, p = 0.042). CONCLUSION: The AHR of brainstem CMs decreased following radiosurgery, and our study revealed a significant dose-response relationship. Margin doses of 14-15 Gy were recommended. Further studies are required to validate our findings.

Extra-axial cavernous malformations of the foramen magnum: illustrative cases.

BACKGROUND: Extra-axial cavernous malformations involving the foramen magnum are rare, and preoperative diagnosis becomes difficult when they mimic meningiomas. OBSERVATIONS: The authors present 2 cases of extra-axial cavernous malformations involving the foramen magnum. Surgical removal of the lesions was performed via far lateral craniotomy. The authors investigate the disease and elaborate the differential diagnosis. LESSONS: The authors recommend that extra-axial cavernous malformations should be considered in the differential diagnosis of lesions in the foramen magnum region. Intraoperative frozen sections are helpful to the diagnosis, and resection warranted a favorable long-term outcome.