The postorbital approach to the middle cerebral artery in cats.

The study of the relation between behavior, cerebral blood flow, and metabolism in animal models of cerebral ischemia has gained interest in the last 10 years. The most suitable models are those with the fewest side effects. One-sided blindness caused by decompression of the eye and coagulation of the optic nerve has been an inevitable side effect of transorbital occlusion of the middle cerebral artery. The postorbital technique is a new surgical approach to the middle cerebral artery that leaves the intraorbital structures intact. After resection of the postorbital processes and gentle retraction of the eye, the optic foramen is approached with the help of an operating microscope. This approach is possible because cats have no lateral bony orbital wall. A subperiostal approach to the optic foramen is made, after which the optic foramen is enlarged. Opening of the dura gives access to the middle cerebral artery in the same way as the transorbital approach. In this way, occlusion of the middle cerebral artery is possible with minimal impairment of vision.