[Clinical study of ventriculo-lumbar perfusion in the patients of so-called normal pressure hydrocephalus (author's transl)].

The cerebrospinal fluid dynamics were studied in the ten patients between 33 and 67 years old with signs of so-called normal pressure hydrocephalus by the technique of ventriculo-lumbar perfusion. The perfusion fluid with Ringer's solution or Hartmann's solution containing tracer amounts (25 mg/dl) of insulin. The inflow fluid warmed up to the body temperature was introduced by the infusion pump to the trigone of the lateral ventricle through the ventricular tube. The outflow fluid was collected from the lumbar subarachnoid space through the spinal needle inserted into the L4-5 interspace. The perfusion pressure was adjusted by raising and lowering the height of the outflow manometric pressure relative to the spinous process. The distribution volume of the perfusion system was the range of 94 - 209 ml (average 136 ml) and exceeded the normal range. The formation rate of cerebrospinal fluid was the range of 0.21 - 0.69 ml/min (average 0.39 ml/min) at the opening pressure, and nearly equal to the bulk absorption rate. There was the relationship between the bulk absorption rate and the perfusion pressure, and the regression coefficients in nine cases were lower than reported in normals. The clinical condition of seven of the nine patients demonstrating this absorptive deficit improved after cerebrospinal fluid shunting. The perfusion test was useful to recognize the cerebrospinal fluid dynamics and also to determine the indication of cerebrospinal fluid shunt in the patients of so-called normal pressure hydrocephalus.