Clinical comparison of the Spiegelberg parenchymal transducer and ventricular fluid pressure.

The Spiegelberg brain pressure catheter is a low cost implantable intracranial pressure measuring system which has the unique ability to perform regular automatic zeroing. A new version of the catheter has become available with a subdural bolt fixation to allow insertion of the device into the brain parenchyma. The accuracy of this system has been evaluated in comparison with a ventricular fluid pressure method in a series of patients to determine its accuracy and utility in the clinical environment. Hourly readings from the Spiegelberg system have been compared with those obtained using a standard pressure transducer connected to an external ventricular drain. Measurements continued while there was a clinical need for CSF drainage. Eleven patients were recruited to the study and data were recorded for periods ranging from 40 to 111 hours. A good agreement between the two systems was obtained. In 10 cases the mean difference was less than +/-1.5 mm Hg and the dynamic changes in value were contemporaneous. In one case an intracerebral haemorrhage developed around the tips of the Spiegelberg catheter and significant differences occurred between the two methods of measurement. In conclusion, the Spiegelberg parenchymal transducer provides an accurate measurement of intracranial pressure when compared with ventricular pressure. The transducer was found to be robust in the clinical environment and very popular with the nursing staff. Further studies may determine whether the complication rate of this system is comparable with other available devices.