title: Effect of cerebrospinal fluid shunts on intracranial pressure and on cerebrospinal fluid dynamics. 2. A new technique of pressure measurements: results and concepts. 3. A concept of hydrocephalus.
abstract: Part 2 describes measurements of intracranial cerebrospinal fluid (CSF) pressure in 18 adult patients with CSF shunts, all pressure measurements being referred to a horizontal plane close to the foramina of Monro. All 18 patients had normal CSF pressure by lumbar puncture; however, in one patient an intracranial pressure of +280 mm was subsequently measured after pneumoencephalography. Twelve patients had pre-shunt CSF pressures measured intracranially: 11 ranged from +20 to +180 mm H(2)O and one was +280 mm H(2)O in the supine position. In the upright posture nine patients had values of -10 to -140 mm H(2)O, while three others were +60, +70, and +280 mm H(2)O. After CSF shunting in these 18 patients the pressures were -30 to +30 mm H(2)O in the supine position and -210 to -370 mm in the upright position. The effect of posture on the siphoning action of these longer shunts in the erect, adult patient is a major uncontrollable variable in maintenance of intracranial pressure after shunting. Other significant variables are reviewed. In Part 3 a concept of the hydrocephalus phenomenon is described. Emphasis is placed on the pressure differential (P(d)) and force differential (F(d)) causing pre-shunt ventricular enlargement and post-shunt ventricular size reduction. The site of P(d), which must be very small and not to be confused with measured ventricular pressure, P, must be at the ventricular wall.
mesh_terms: D000328:Adult; D000368:Aged; D001794:Blood Pressure; D014695:Cerebral Ventriculography; D002557:Cerebrospinal Fluid Shunts; D002560:Cerebrovascular Circulation; D005069:Evaluation Studies as Topic; D005260:Female; D006801:Humans; D006849:Hydrocephalus / Q000000981:diagnostic imaging / Q000503:physiopathology*; D007427:Intracranial Pressure; D008297:Male; D008722:Methods; D008875:Middle Aged; D011011:Pneumoencephalography; D011187:Posture; D012711:Serum Albumin, Radio-Iodinated; D013129:Spinal Puncture; D014159:Transducers
chemical_list: D012711:Serum Albumin, Radio-Iodinated