The fontanelle tonometer: a noninvasive method for measurement of intracranial pressure.

The use of a modified pneumotonometer as a noninvasive method to measure intracranial pressure through the fontanel was evaluated in the animal laboratory and in the clinical setting. Pressure measured with the tonometer from a surgically created fontanel in an adult mongrel dog demonstrated good correlation with pressure measured from an epidural balloon catheter. Pressure recorded with the tonometer was compared with direct measurements in a single infant. There were 20 paired measurements with a correlation coefficient of 0.91. Fontanel pressure was measured in 72 healthy infants. The mean pressure was 7.0 mm Hg with a standard deviation of 1.75. This result compares favorably with previous reports utilizing other methods. The machine is safe and simple to use.