The dura was cut carefully to facilitate penetration of solutions.
After the dura mater was excised, the pia mater was eliminated under the microscope control with a tungsten wire sharpened to 1-2 mm.
The dura mater was dissected for visualization of the injection zone.
Intra-cranial pressure was reduced by release of the cerebrospinal fluid through an opening of the dura mater at the foramen magnum.
The dura mater was carefully removed in order not to damage the dorsal sagittal sinus.
The dura was reflected to expose the cortex.
The dura was closed with 9-0 suture, muscle reapposed and skin closed with wound clips.
After removing the dura, the chamber was filled with silicone oil and sealed with a round glass coverslip.
