In 1962, NRL developed a surgical technique for correcting intracranial aneurysms to supplant older methods of obliterating these blood-filled arterial dilations. Using a newly developed air gun, called a pilojector, the surgeon fires one or more short pig bristles into the prominence. Blood around the bristle begins to clot immediately, sharply reducing the size of the aneurysm and strengthening the arterial wall. Only slightly larger than a pencil, the pilojector offers precise control of position, injection velocity, and penetration.

Diagram of a pilojector

Artist concept shows the firing of compressed air into a plunger, which then shoots a 1/4-inch-long hog bristle into an aneurysm.