Mesothelial cell integrity of the subdural and arachnoid surfaces of the cat brain after exposure to neurosurgical irrigation fluids and air: a scanning electron microscopic study.

The mesothelial cell integrity of the subdural and arachnoid surfaces in the cat was investigated by scanning electron microscopy after exposure to different irrigation fluids used in neurosurgery, as well as after drying by air. Irrigation for 3 hours with Elliott's Solution B and Ringer's solution retained the morphology of the cells. After exposure to saline for the same time, the mesothelial cells appeared perforated and were sometimes detached from the underlying connective tissue. Exposure to air for 15 minutes induced extensive, probably irreversible, cell damage. After 5 minutes of exposure to hydrogen peroxide, most cells disappeared, revealing the underlying collagenous connective tissue. These mesothelial cell changes might be one cause of the formation of postoperative subdural adhesions. In previous studies, disturbance of the blood-brain barrier was produced by those agents causing mesothelial cell damage. With hydrogen peroxide, widespread thrombosis occurred in leptomeningeal vessels supplying the cortex. Changes in these vessels can obviously be induced easily by fluids applied to the subdural space because of the close contact between the arachnoid and the adventitia of the vessels. This alternative should be considered in the treatment of cerebral vasospasm.