CyberKnife radiosurgery for spinal intramedullary arteriovenous malformations: a single-center experience.

BACKGROUND: Intramedullary spinal AVM (ISAVM, glomus type) is a type of spinal cord arteriovenous malformation, which is a rare disease known often to have a complex vascular supply interfering with that of the spinal cord, and is in complex anatomical relations with cord structures and nerve roots. Though microsurgical and endovascular treatment has mainly been the standard options, in high-risk cases with these treatments, stereotactic radiotherapy (SRT) might be the option of choice.

METHOD: We retrospectively reviewed 10 consecutive patients with ISAVM who received SRT using CyberKnife® (Accuray, Inc., Sunnyvale, CA) at the Japanese Red Cross Medical Center (Tokyo, Japan) from 2011/1-2022/3.

RESULTS: No case in this series suffered from hemorrhage after applying SRT. One case experienced neurological impairment ten years after SRT, which we attributed to venous congestion due to the remaining lesion. No case of radiation myelopathy was observed in this series. In one case, the nidus volume reduction and loss of flow voids were obvious, though improvement in the neurological outcome was not apparent. No radiological changes were observed in the other nine patients.

CONCLUSION: Even in lesions without radiological changes, no hemorrhagic events were observed for an average period of 4 years. SRT may be a feasible option in treating ISAVM, especially for lesions in which microsurgical resection and endovascular treatment are inapplicable. To ascertain the safety and efficacy of this approach, further studies with more patients and longer follow up is required.