Endoscopic ventriculostomy versus shunt operation in normal pressure hydrocephalus: diagnostics and indication.

In contrast to the shunt operation the indication for an endoscopic ventriculostomy in patients diagnosed for normal pressure hydrocephalus is not scientifically established. Between September 1997 and December 1999 we operated on 48 patients diagnosed for normal pressure hydrocephalus. The diagnosis was established by means of the intrathecal lumbar or ventricular infusion test, the cerebrospinal fluid tap test and MRI-CSF flow studies pre- and postoperatively. In 37 patients (77%) we have implanted a ventriculo-peritoneal shunt, and in 11 patients (23%) we performed the endoscopic assisted third ventriculostomy. With our created NPH recovery rate and use of the clinical grading for normal pressure hydrocephalus created by Kiefer and Steudel we compared the operative results of both groups of patients. In patients with a pathologically increased resistance to CSF outflow in the lumbar infusion test a shunt implantation is indicated. Patients whose outflow resistance is increased in the ventricular infusion test but with a physiological lumbar infusion test are suspected for a functional aqueduct stenosis and should be treated by means of endoscopic assisted ventriculostomy.

[Pressure-dependent flow resistance in craniospinal cerebrospinal fluid dynamics: a calculation model for diagnosis of normal pressure hydrocephalus]. / Der druckabhängige Abflusswiderstand in der kraniospinalen Liquordynamik: ein Berechnungsmodell zur Diagnostik des Normaldruckhydrozephalus.

Computer-aided processing of the results obtained with the intrathecal infusion test using our newly developed mathematical model simplifies the investigation technique and thus the diagnosis of normal pressure hydrocephalus. Simultaneous determination of resistance and compliance in a single session markedly reduces the examination-related stress on the patient. In contrast to the classical methods, the new calculation does not require the ICP to reach a plateau. Unlike the static approach, our model describes the functional pressure-dependent course of the resistance. This means that account is taken of the non-linearity of the CSF dynamics during the processing of the biosignal. The intrathecal infusion test used to measure resistance and compliance is a reliable diagnostic method in patients with a normal pressure hydrocephalus.

[Clinical experience with various shunt systems in normal pressure hydrocephalus]. / Klinische Erfahrungen mit verschiedenen Shuntsystemen beim Normaldruckhydrozephalus.

In patients with normal pressure hydrocephalus in the late stage conventional differential valves have the disadvantage that they open abruptly while changing the body position to the vertical line and that they can therefore induce a suction on the ventricles of the atrophic brain. Can these disadvantages and overdrainage complications be minimized by hydrostatic valves? In 117 patients diagnosed for normal pressure hydrocephalus we have implanted 47 Cordis Standard Valves (CSV), 20 Cordis Orbis Sigma Valves Type I (OSV) and 50 Miethke Dual Switch Valves (DSV). 95 patients (36/19/40) could be re-evaluated by means of a control examination. Normal pressure hydrocephalus was graduated according to the results of the intrathecal infusion test in an early and late stage. According to our NPH-Recovery-Rate and to the clinical grading of normal pressure hydrocephalus by Kiefer and Steudel we compared the post-operative results of each group of patients. There were no statistical differences in mechanical and infectious complications between the different valve types. We found significant differences in overdrainage and subdural hematomas. 4 patients (11%) with a CSV, 5 patients (26%) with an OSV and 2 patients (5%) with a DSV had a decrease of the ventricular width visualised in the CT. Of those patients 2 (6%) with a CSV, 3 patients (16%) with an OSV and 1 patient (3%) with a DSV developed clinical symptoms. The course of the disease in patients with normal pressure hydrocephalus is influenced by the stage of the disease--degree of cerebral atrophy--and also by the implanted valve type. The high amount of overdrainage complications and subdural hematomas in the Cordis Orbis Sigma Valve Type I group is an argument against its use. Our clinical experiences with the Miethke Dual Switch Valve show that this hydrostatic valve is of advantage for patients with a normal pressure hydrocephalus.

The use of decompressive craniectomy for the management of severe head injuries.

The aim of Neurosurgical care is to minimise the secondary brain damage that occurs after a severe head injury. This includes the evacuation of an intracranial space occupying haematoma, the reduction of intracranial volume, external ventricular drainage with hydrocephalus, and conservative therapy to reduce intracranial pressure (ICP) and to maintain tissue oxygen p(ti)O2. When conservative treatment fails, a decompressive craniectomy might be successful in lowering ICP. From September 1997 until April 1999 we operated on 128 patients with severe head injuries. 19 patients (15%) were treated by means of a decompressive craniectomy. The prognosis after decompression depends on clinical signs and symptoms on admission, patients' age and the existence of major extracranial injuries. Our guidelines for decompressive craniectomy after failure of conservative intervention and evacuation of space occupying hematomas included: a patient's age below 50 years without multiple trauma or a patient's age below 30 years in the presence of major extracranial injuries; severe brain swelling on CT scan (primary brainstem injuries were excluded). In 8 patients conservative 1TU treatment had failed.

Clinical experiences with the dual-switch valve in patients with normal pressure hydrocephalus.

In patients with normal pressure hydrocephalus (NPH) we compared the postoperative results reference to the implanted valve type. In 117 patients diagnosed with normal pressure hydrocephalus there was placement of 47 Cordis Standard valves (CSV), 20 Cordis Orbis Sigma valves type I (OSV) and 50 Miethke Dual-switch valves (DSV). Ninety-five patients (36/19/40) were re-evaluated. Normal pressure hydrocephalus was graduated according to the results of the intrathecal infusion test in an early and late stage. There were no statistical differences in mechanical and infective complications between the different valve types. We found significant differences in overdrainages and subdural hematomas. Two patients (6%) with a CSV, 3 patients (16%) with an OSV and 1 patient (3%) with a DSV developed clinical symptoms due to this. The course of disease in patients with NPH is influenced by the stage of disease--degree of cerebral atrophy--and also by the implanted valve type. The great amount of overdrainage complications and subdural hematomas in the Cordis Orbis Sigma valve group may be an argument against this valve. Our clinical experiences with the Miethke Dual-switch valve show that this hydrostatic valve may be advantageous for patients with NPH.

Endoscopic ventriculostomy versus shunt operation in normal pressure hydrocephalus: diagnostics and indication.

In contrast to shunt operation the indication for an endoscopic ventriculostomy in patients diagnosed for normal pressure hydrocephalus is not scientifically established. From September 1997 to March 1999 we operated on 36 patients diagnosed for normal pressure hydrocephalus. Diagnosis was established by means of the intrathecal lumbar or ventricular infusion test, the cerebrospinal fluid tap test and MRI-CSF flow studies pre- and post-operatively. In 30 patients (83%) we implanted a ventriculo-peritoneal shunt, and in 6 patients (17%) we performed the endoscopic assisted third ventriculostomy. With our created NPH recovery rate and use of the clinical grading for normal pressure hydrocephalus created by Kiefer and Steudel we compared the operative results of both patient groups. In patients with a pathologically increased resistance to CSF outflow in the lumbar infusion test a shunt implantation is indicated. Patients whose outflow resistance is increased in the ventricular infusion test but with a physiological lumbar infusion test are suspected for a functional aqueduct stenosis and should be treated by means of an endoscopic assisted ventriculostomy.

Signs, symptoms and course of normal pressure hydrocephalus in comparison with cerebral atrophy.

Between May 1982 and January 1997 we investigated 200 patients for normal pressure hydrocephalus (NPH) by performing an intrathecal infusion test. 168 patients (84%) presented with the clinical syndrome of gait ataxia, dementia and urinary incontinence, the so called Adams triad. In 107 patients (54%) the diagnosis of a NPH could be confirmed. Of these, 102 patients (95%) underwent a shunt operation. In a follow-up (7 month and 3 years later) we interviewed the patients or their relatives about the progression of the disease. At those time intervals we could evaluate the improvement after shunt operation or infusion test. In our experience gait ataxia is the guiding sign of NPH. Regarding dementia we could not find a significant difference compared to cerebral atrophy. Urinary incontinence can be characterized as a symptom of late stage NPH. The complete Adams triad should not be overestimated in differential diagnostic considerations. Subdivision of NPH into an early stage and a late stage allows one to conclude prognostic evaluations about the course of the disease. Patients with an early stage NPH reported at the follow-up an improvement of their symptoms after shunt operation in 65 percent and those with a late stage NPH in 50 percent. The computer aided infusion test allows a safe differentiation between patients with NPH and those with cerebral atrophy.

Diagnostic in normal pressure hydrocephalus: A mathematical model for determination of the ICP-dependent resistance and compliance.

The internationally accepted calculation methods concerning cerebrospinal fluid dynamics proceed from a pressure independent resistance to cerebrospinal fluid outflow. In a new model we focus our attention on the pressure dependency of resistance. In our calculation model we are monitoring the complete pressure course p(t) over the time during and after the infusion. The comparison of the pressure rise On(p) during the infusion and the descent Off(p) after the infusion at the same pressure level allows one to construct all formulas for the compliance C(p) and resistance R(p). The computerized analysis of the results of the intrathecal infusion test using our mathematical computation leads to a simplification of this investigation. The simultaneous measurement of the resistance and compliance during a single investigation allows one to minimize the patient's discomfort. In contrast to the classical methods it is not necessary that the ICP reaches a plateau. Our mathematical method diverges with the description of a pressure dependent slope of the function for the resistance from the static examination models. For that we are able to take the non-linearity of the cerebrospinal fluid resorption into consideration.

[Clinically suspected normal-pressure hydrocephalus diagnosis--current status of diagnosis and therapy]. / Klinische Verdachtsdiagnose Normaldruck-Hydrocephalus--gegenwärtiger Stand der Diagnostik und Therapie.

Since the first description of the disease normal pressure hydrocephalus (NPH), there has been a great progress in the diagnosis of this disease. Taking into account that the age of the population is rising the incidence and social medical importance is increasing. Modern neuroradiological techniques are visualising a ventricular enlargement but a definitive diagnosis cannot be drawn. The intrathecal infusion tests represent a save and valid tool while measuring the cerebrospinal fluid dynamics. Shunting is the only possible therapy in NPH. Complications from shunting are still a great problem and therefore, a definite diagnosis must be gained in order to avoid a shunt induced morbidity and mortality.

[Psychophysiology, signs and symptoms of disease the course of normal pressure hydrocephalus]. / Pathophysiologie, Klinik und Krankheitsverlauf beim Normaldruckhydrozephalus.

Between May 1982 until January 1997 we investigated 200 patients suspected for normal pressure hydrocephalus (NPH) by performing an intrathecal infusion test. According to our experiences gait ataxia is the leading symptom of NPH. Regarding dementia we could not find a significant difference compared to cerebral atrophy. Bladder incontinence can be characterised as a symptom of late-stage NPH. The complete Hakim trias should not be overestimated in differential diagnostic considerations. Graduation of NPH and cerebral atrophy after the results of the infusion test in an early and late stage enables prognostic evaluation of the course of disease. Patients with NPH in an early stage report in the follow-up on an improvement of their symptoms after shunt operation (65 percent of patients), whereas 50 percent of the patients with late stage NPH were improved. The computer-aided infusion test allows secure differentiation between patients with NPH and those with cerebral atrophy.

[Fractures of the lower cervical spine. Surgical methods and long-term outcome]. / Frakturen der unteren Halswirbelsäule. Operationsmethoden und Langzeitergebnisse.

Between 1980 until 1996 we operated altogether 327 patients because of a discoligamentous or osseous injury of the lower cervical spine. In a retrospective examination we evaluated the type of the injuries, the mechanism of the accidents, the neurological status on admission and the postoperative result. With regard to the long-term results we re-investigated 170 patients who have been operated on in our Department of Neurosurgery. In none of the patients we could find a neurological deterioration after the operation. The prognosis for patients with an incomplete and complete transversal syndrome is worse concerning a regression of the neurological deficit. The ventral spondylodesis in the technique according to Cloward-Crock, Robinson and Smith and Bailey-Badgley with ventral plate fixation provided the best results and we recommend these techniques for injuries of the lower cervical spine.

[Diagnosis of normal pressure hydrocephalus. A calculation model for determining intracranial pressure-dependent resistance and compliance]. / Zur Diagnostik des Normaldruckhydrozephalus. Ein Berechnungsmodell zur Ermittlung der ICP-abhängigen Resistance und Compliance.

Computer-aided analysis of the results of the intrathecal infusion test using our mathematical computation leads to simplification of this investigation, and therefore normal pressure hydrocephalus is more easily diagnosed. Simultaneous measurement of resistance and compliance during a single investigation allows the exertion of the patients to be minimized. In contrast to classic methods it is not necessary that the ICP reaches a plateau. Our mathematical method diverges with the description of a pressure-dependent slope of the function for the resistance from the static examination models. For that we are able to take the non-linearity of the cerebrospinal fluid resorption into consideration. The intrathecal infusion tests is a reliable diagnostic method for measuring resistance and compliance in patients suspected of having normal pressure hydrocephalus.