Abstract
In surgeries for spinal cord tumors and spinal arteriovenous malformations (AVM) , it is important to detect boundaries between the lesion and normal spinal cord. When we can visualize the border, we have a higher chance to remove or resect lesions without invading the surrounding spinal cord. For this purpose, we used 5-aminolevulinic acid (5-ALA) and indocyanine green (ICG) videoangiography in surgeries for intramedullary tumors. In astrocytic tumors, 5-ALA showed red fluorescence. ICG videoangiography demonstrated cavernous angioma as an avascular area in the spinal cord. They both helped surgeons to locate and dissect the tumors.
In spinal AVMs, preoperative simulation played an important role in visualizing complex vasculatures. Three-dimensional fusion images demonstrated the relationship between the AVM and the spinal cord. By understanding the angioarchitecture of the spinal AVM, we could establish the correct diagnosis and choose the appropriate treatment strategy from among endovascular embolization, open surgery, or a combination of both.
In surgery for spinal AVMs including dural AV shunts, perimedullary AV shunts, and intramedullary AVMs, ICG videoangiography is now regarded as a routine examination. Especially in surgery for perimedullary AV shunting, we utilize an endoscope (30 or 70 degrees) to visualize the spinal cord surface in different angles from a microscope and in higher magnification. When we approach the spinal cord through the posterior exposure, the assisted use of endoscopy provides a circumferential view of the spinal cord. Thus, the anterior spinal artery and veins can be visualized.
With appropriate use of surgical adjuncts in spinal cord surgeries, we believe that we have more chances to achieve the maximum degree of tumor removal and AVM disconnection as well as preservation of spinal cord functions.
