[Prospects of CyberKnife stereotactic radiation therapy for cerebral vascular malformations and functional diseases].

Minimally invasive stereotactic radiation therapy has become one of the promising options for treating patients with intracranial diseases. Among the currently available instruments, the CyberKnife system (Accuray Inc., Sunnyvale, CA) is a unique apparatus equipped with image-guided target locating system. Because this system does not rely on rigid frame immobilization with screws, it has several distinct advantages over frame-based systems, including improved patient comfort and increased treatment degrees of freedom. In particular, this system has enabled selection of single-session and multi-session stereotactic radiation therapies, depending on the size, shape, and position of the lesions. Furthermore, this device is expected to aid stereotactic radiation therapy for large lesions that cannot be treated because of the size; moreover, it causes less damage to normal structures. In this article, we describe the advantages of the Cyberknife system for the management of vascular malformations and functional diseases.

[Treatment for the ruptured bilateral vertebral dissecting aneurysms].

We report a case of a bilateral vertebral dissecting aneurysm associated with subarachnoid hemorrhage. Proximal ligation of the vertebral artery on the ruptured side combined with wrapping of the contralateral dissection failed to prevent fatal rebleeding. Since enlargement of the contralateral dissection was observed by postoperative angiography, rupture of the growing contralateral dissecting aneurysm may have caused rebleeding. Hemodynamic changes following the occlusion of one vertebral artery might have led to enlargement and subsequent rupture of the contralateral dissection. Direct wrapping was unable to prevent enlargement of the dissection, so radical surgery including bilateral vertebral artery occlusion combined with vascular reconstruction may be the treatment of choice for this type of lesion.

[Cranioplasty using the patient's autogenous bone preserved by freezing--an examination of post-operative infection rates].

The current technique for cranioplasty using artificial bone requires further improvement with regard to infection, strength and comfort through good fitting. We have carried out cranioplasty using the patient's autogenous bone flap obtained during first surgery. It was immersed in 200 mg of Amikacin Sulphate, and frozen at -16 degrees C until its use in cranioplasty. From 1980 to 1998, cranioplasty has been carried out on 206 patients. They consisted of 118 males and 88 females, and their age ranged in our institute from 1 to 81; average age 51.1. Ruptured aneurysm (48%), head injury (14%), intracranial hemorrhage (23%) and cerebral infarction (12%) were the major causes requiring decompression surgery. We analyse the bone preservation period and the time between cranioplasty and the onset of infection. The infection rates per bone preservation periods, the causes of decompression and age groups are studied. Of the 208 case studies, infection necessitating bone removal or debridement was noted in 8 cases (3.88%). Average bone preservation period in the infected group was 31.1 days as compared with 54.9 days for the non-infected group (p < 0.05). Not patient age but the type of head injury is also a significant factor in post cranioplasty infection.