gms | German Medical Science

Objective: Both over- as well as underdrainages are well-known complications in patients treated with ventriculoperitoneal shunt due to hydrocephalus. Clinical evaluation in sophisticated hydrocephalic diseases is often aggravated by symptoms such as headache and vertigo, which do not allow a distinction between over- and underdrainage. After implantation of an intracranial sensor, telemetric intracranial pressure (ICP) measurements may indicate the pathology. However, parallel conveyed patients' diaries provide insufficient information in regard to the precise position and timing for the evaluation of position-dependent complaints. The aim of our study was to improve the subjective diagnostic of telemetric ICP measurement by the concomitant, precise registration of the patients’ position.

Method: In this prospective study, ICP was measured by a telemetric probe (p-tel, Raumedic). Body position was recorded by an Apple iPhone application (Gyrorecorder, OS Craft). Patients fulfilled a course of standard maneuvers as well as symptom-inducing activities. In a blinded evaluation, conducted by three independent neurosurgeons, ICP graphs alone were evaluated. The neurosurgeons rated their diagnostic certainty, the need and, if necessary, kind of opening pressure changes. Afterwards, ICP graphs together with the position records were shown and the rating was repeated.

Results: 12 patients with different types of hydrocephalus, treated with adjustable VP-shunts and with persisting symptoms were included. Altogether, 25 measurements were conducted with a mean length of 250 minutes (60-460 minutes). As expected, the evaluation of position related to the ICP improved by adding position information in all cases (p=0.0025, Wilcoxon signed-rank test). By having information on the body position, the diagnostic certaintyof the neurosurgeons increased in 80.6% of the cases (p=0.0001, Wilcoxon signed-rank test). Furthermore, the proposed changes of the opening pressure of the valves differed in 50.1% of the cases, if additional information on body position was given. Additional position information was considered as useful for decision making in 86.1%.

Conclusions: The co-registration of the body position facilitates the interpretation of telemetrically measured ICP changes, alters decision making in terms of changing the opening pressure of a valve in 50% and improves the diagnostic certainty of the neurosurgeon.