The case of 49-year-old woman with a ruptured dissecting aneurysm of the left vertebral artery is reported in this paper. She was admitted complaining of severe headache and became moribund after re-bleeding attacks. CT scan demonstrated massive subarachnoid hemorrhage, especially around the brainstem, and intraventricular hematoma. Vertebral angiography showed the so-called“string and pearl sign”in the left vertebral artery just distal of the origin of the posterior inferior cerebellar artery and no abnormality in the well-developed right vertebral artery. The aneurysm was located at midline, therefore and advanced lateral suboccipital approach was used. This can be done through the space made by drilling off the lateral part of the foramen magnum. The aneurysm was thus easily trapped without any retraction of the cerebellum. And then extensive clot evacuation was done around the brainstem and in the fourth ventricle. Fortunately, the patient gradually recovered after surgery, but with some mental incapacity. In conclusion, we would like to emphasize that a moribund patient can not be cured without immediately removing the aggravating factors as quickly as possible. And pre-operative diagnosis may be the most important factor in the therapy of dissecting aneurysms.
