Intracranial pressure measurement also possible without opening the skull
In many diseases of the brain, especially after traumatic brain injuries, it is necessary to measure the pressure inside the brain in order for the doctor to be able to determine the appropriate treatment. Until now, these measurements were only possible by opening the cranial bone through a drill hole and inserting the probe to measure the pressure. Scientists at the Otto-von-Guericke University in Magdeburg have recently developed a non-invasive method of measuring intracranial pressure so that in future there is no need to open the skull surgically. The results of this novel procedure were published in The Lancet on February 14, 1998. This method, which for the first time allows a reliable, bloodless estimation of the intracranial pressure, was developed in the Department of Neurosurgery at the Otto von Guericke University in Magdeburg (working group of Prof.dr Raimund Firsching) developed together with the University Eye Clinic Magdeburg (working group Prof. Dr. Wolfgang Behrens-Baumann). "Since the eye evolved from the brain tissue, it was reasonable to think that pressure forces that affect the brain could also affect the eye via the optic nerve," says neurosurgeon Professor Firsching, explaining the research collaboration with doctors at the eye clinic.
The new procedure is based on the anatomical principle, according to the scientist, that the retina takes its venous drainage via the optic nerve, which is surrounded by cerebrospinal fluid and is therefore related to the intracranial pressure. If the intracranial pressure increases, the optic nerve is compressed and blood flow from the retina is impeded. With a pressure gauge, the intraocular pressure can be determined as desired, the fundus can be evaluated with an ophthalmoscope. If the intraocular pressure exceeds the venous pressure, the vein collapses. In this way, the exact level of pressure in the vein that drains the blood from the retina can be determined.
"In the event of an increase in intracranial pressure, an exact connection between retinal vein pressure and intracranial pressure could be demonstrated in more than 20 patients in whom the intracranial pressure was measured for special reasons - primarily with suspected hydrocephalus or craniocerebral injury ", informs Professor Fisching. Among other things, the method is of practical importance for differentiating in patients with hydrocephalus in whom the cerebrospinal fluid has been drained, for example whether vomiting is due to an increase in intracranial pressure due to a malfunction of the drainage system or to a gastrointestinal infection that has developed in the meantime.
Professor Firsching: Since the method of measuring retinal vein pressure, oculodynamometry, can provide an indication of the intracranial pressure, not only the ophthalmologist, but also the general practitioner, the neurologist and the neurosurgeon should be familiar with the method."
The connection, which has now been proven for the first time, was suspected as early as 1920, but at that time there were only insufficient possibilities for precise pressure measurement.
Otto von Guericke University Magdeburg was founded in 1993 and is one of the youngest universities in Germany.