Intrathecal Infusion Test Research Articles

Zur Diagnostik des idiopathischen Normaldruckhydrozephalus aus der Perspektive von Langzeitbeobachtungen

Currently there is no gold standard and no non-invasive diagnostic method for the normal-pressure hydrocephalus which allows a valid prediction of the outcome after a shunt operation. The experience of our working group includes 670 patients whom we examined between May 1982 and September 1997 in the Department of Neurosurgery of the Friedrichshain Hospital and between September 1997 and July 2005 in the Department of Neurosurgery of the Unfallkran-kenhaus in Berlin using non-invasive and invasive methods. We performed 717 lumbar and ventricular infusion tests. A walking disorder plus at least one other symptom of the HAKIM triad as well as the intrathecal infusion test and/or the cerebrospinal tap test (clinical improvement after removal of at least 50 ml of cerebrospinal fluid) were needed to establish the diagnosis of a normal pressure hydrocephalus. 348 patients (52%) fulfilled these criteria. We compared our own experiences with those of other groups by a systematic review of the recent literature. We therefore searched for English and German papers in medline with idiopathic normal pressure hydrocephalus AND 1997/09: 2005/07 [Publication Date]. We found 89 papers with a publication date between September 1997 and July 2005. Due to the evidence criteria we selected all original papers in which more than 30 patients were examined with follow-up time of 6 months and more for our analysis. In our opinion only a subtle preoperative diagnostic leads to good long-term results. In every patient the indication should be proved with clinical, neuroradiological and invasive methods. At the same time we have to stress the importance of long-term follow-ups to avoid late complications.

Clinical impact of the intrathecal infusion test to distinguish between Normal Pressure Hydrocephalus (NPH) and Dementia

Clinical impact of the intrathecal infusion test to distinguish between Normal Pressure Hydrocephalus (NPH) and Dementia

Idiopathischer Normaldruckhydrozephalus

The measurement of CSF flow in the aqueduct has been a focus of interest since the development of MR imaging (MRI) techniques for this purpose in diagnosing idiopathic normal-pressure hydrocephalus (iNPH).The purpose of this prospective study was to determine the ability of this diagnostic tool to replace invasive methods in establishing the diagnosis of iNPH. Between January 2003 and April 2005, 61 patients with the Hakim triad of clinical symptoms and dilated ventricular systems underwent the intrathecal infusion test, cerebrospinal tap test, and phase-contrast MRI to measure CSF flow rate in the aqueduct. Shunted patients were controlled 12 months postoperatively. Pre- and postoperative clinical symptoms were evaluated with the Kiefer score. Outcome was calculated according to the NPH recovery rate. According to these criteria the patients were classified into groups of 41 with iNPH and 20 with brain atrophy. Of the iNPH patients, 39 were shunted and two did not agree to surgery. The mean Kiefer score of the shunted patients was statistically significantly lower after surgery. The aqueductal CSF flow rate of these patients was statistically analyzed and showed that a flow rate of more than 24.5 ml/min is 95% specific to iNPH. Measurement of the CSF flow rate in the aqueduct using phase-contrast MRI is a highly specific preselective method for diagnosing iNPH.

Clinical impact of the intrathecal infusion test to distinguish between Normal Pressure Hydrocephalus (NPH) and Dementia

Clinical impact of the intrathecal infusion test to distinguish between Normal Pressure Hydrocephalus (NPH) and Dementia

Predictors of Outcome in Patients with Normal-Pressure Hydrocephalus

Despite emerging knowledge of over 40 years, the postoperative results after shunt implantations in patients diagnosed for normal-pressure hydrocephalus (NPH) have not improved significantly in the last decade. For this reason, predictors have to be identified in order to preoperatively predict the course of disease. From 1982 to 2000, we examined in a prospective study 200 patients diagnosed for NPH. Of the patients who were surgically treated by a shunt implantation we could re-examine 155 (78%) in a mean time interval of 7 months after operation. The NPH was graduated according to the results of the intrathecal infusion test in an early state NPH (without brain atrophy) and late state NPH (with brain atrophy). In the study we focused our attention on the possible predictors: patient’s age, length of disease, clinical signs – like gait ataxia, dementia and bladder incontinence, etiology idiopathic/secondary as well as implanted valve type and the value of resistance to cerebrospinal fluid outflow. To measure the outcome we used the NPH recovery rate, as statistical test the χ² according to Pearson. In 80 patients with an early stage NPH (without cerebral atrophy) and a short course of disease (<1 year), slightly distinct dementia and an implanted Miethke Dual-Switch valve were significant predictors for a positive postoperative outcome. The outflow resistance measured in the intrathecal infusion test showed only a minimal relevance for the outcome. Those 75 patients with a late state NPH (with cerebral atrophy) had a better outcome when dementia was not present, the outflow resistance was >20 mm Hg·min/ml, the CSF tap test was positive and a Miethke Dual-Switch valve was implanted.

Predictors of outcome in patients with normal pressure hydrocephalus

Despite emerging knowledge over 40 years, the postoperative results after shunt implantations in patients diagnosed for normal pressure hydrocephalus (NPH) did not improve significantly during the last decade. For that reason predictors have to be identified in order to predict preoperatively the course of disease. From 1982 until 2000 we examined in a prospective study 200 patients diagnosed for NPH. From the patients, who were surgically treated by a shunt implantation we could reexamine 155 (78%) in a meantime interval of seven month after the operation. The NPH was graduated according to the results of the intrathecal infusion test in an early state NPH (without brain atrophy) and late state NPH (with brain atrophy). In our study, we focussed the attention on the possible predictors: patients age, length of disease, clinical signs--like gait ataxia, dementia and bladder incontinence, aetiology idiopathic/secondary as well as implanted valve type and the value of resistance to cerebrospinal fluid outflow. To measure the outcome we used the NPH-Recovery-Rate, as statistical test the Chi-square according to Pearson. In 80 patients with an early stage NPH (without cerebral atrophy) a short course of disease (< 1 year), a just slight distinct of dementia and an implanted Miethke-Dual-Switch valve were significant predictors for a positive postoperative outcome. The outflow resistance measured in the intrathecal infusion test showed only a minimal relevance for the outcome. Those 75 patients with a late state NPH (with cerebral atrophy) had a better outcome when dementia was not present, the outflow resistance was above 20 mm Hg*min/ml, the CSF tap-test was positive and a Miethke-Dual-Switch valve was implanted.

Predictors of outcome in patients with normal-pressure hydrocephalus.

Despite knowledge emerging over the last 40 years, the postoperative results after shunt implantation in patients diagnosed with normal-pressure hydrocephalus (NPH) have not improved significantly over the last decade. For that reason predictors have to be identified in order to preoperatively predict outcome. From 1982 to 2000 we prospectively studied 200 patients diagnosed with NPH. From the patients, who were surgically treated by a shunt implantation we reexamined 155 (78%) postoperatively a mean time interval of 7 months. The NPH was graded according to the results of the intrathecal infusion test in an early stage NPH (without brain atrophy) and late stage NPH (with brain atrophy). In our study, we focussed attention on the possible predictors: patients age, length of disease, clinical signs (gait ataxia, dementia and bladder incontinence), aetiology idiopathic/secondary as well as implanted valve type and the value of resistance to cerebrospinal fluid outflow. To measure the outcome we used the NPH recovery rate and as the statistical test the chi(2) according to Pearson. In 80 patients with an early stage NPH (without cerebral atrophy), a short course of disease (<1 year), a slight degree of dementia and an implanted Miethke-Dual-Switch valve were significant predictors for a positive postoperative outcome. The outflow resistance measured in the intrathecal infusion test showed only a minimal relevance to outcome. Those 75 patients with a late state NPH (with cerebral atrophy) had a better outcome when dementia was not present, the outflow resistance was above 20mm Hg/min/ml, the CSF tap-test was positive and a Miethke-Dual-Switch valve was implanted.

The importance of the intrathecal infusion test in the diagnosis of normal pressure hydrocephalus

The intrathecal infusion test is a reliable method in diagnosing normal pressure hydrocephalus. Between May 1982 and January 2000 we investigated 300 patients suspected of having normal pressure hydrocephalus (NPH) by carrying out an intrathecal infusion test in a constant flow technique. The resistance to cerebrospinal fluid outflow (Rout) in the intrathecal infusion test was the main criterion of grouping patients into those with normal pressure hydrocephalus or those with cerebral atrophy. A further differentiation into early stage and late stage was made by measuring the compliance (Cp) – this being the secondary criterion. In 162 patients (54%) the diagnosis of NPH could be confirmed. Of these, 154 patients (95%) underwent a shunt operation. Graduation of NPH and cerebral atrophy following the results of the infusion test at an early stage and an advanced stage allow the conclusion of prognostic evaluations about the course of disease to be made. Patients with NPH in an early stage report in the follow up an improvement of their symptoms after a shunt operation in 65 percent of cases, and those with advanced stage NPH, in 50 percent of cases. The computer aided infusion test allows a reliable differentiation between patients with NPH and those with cerebral atrophy.

The Grading of Normal Pressure Hydrocephalus / Die Graduierung des Normaldruckhydrozephalus

During a period of 15 years we investigated 200 patients suspected of normal pressure hydrocephalus (NPH) by means of an intrathecal infusion test. In 107 patients (54%) the diagnosis of a normal pressure hydrocephalus could be confirmed. For the evaluation of the course of disease we used the Black-Grading-Scale for shunt assessment [1] and the clinical grading for chronic hydrocephalus (Kiefer-scale) [4] pre- and postoperatively as well as in a follow-up examination seven months after surgical treatment. The aim of our study was to find out a quick and easy-to-handle bed-side examination for the grading of NPH. The Black-Grading-Scale does not allow to distinguish between patients in an unchanged condition and those with a worsening of their symptoms. Therefore this scale is useful for patients with an obstructive hydrocephalus but not for those with a NPH. In our opinion the clinical grading of Kiefer [4] seems to be the most reliable scale for the grading and long term follow-up of a normal pressure hydrocephalus. Our own created NPH-Recovery-Rate is based on the clinical grading for chronic hydrocephalus (Kiefer-scale) [4]. It allows the interindividual comparison between the courses of disease in patients with normal pressure hydrocephalus.

The Importance of the Intrathecal Infusion Test in the Diagnostic of Normal-Pressure Hydrocephalus

Objective: The intrathecal infusion test is a reliable method for diagnosing normal-pressure hydrocephalus (NPH). Methods: Between May 1982 and January 1997, we investigated 200 patients suspected of having NPH by carrying out an intrathecal infusion test with a constant-flow technique. The resistance to cerebrospinal fluid outflow in the intrathecal infusion test was the main criterion for grouping patients into those with NPH or those with cerebral atrophy. A further differentiation into early stage and advanced stage was made by measuring the compliance, this being the secondary criterion. Results: In 107 patients (54%), the diagnosis of NPH could be confirmed. Of these, 102 patients (95%) underwent a shunt operation. Graduation of NPH and cerebral atrophy following the results of the infusion test at an early stage and an advanced stage allows prognostic evaluations about the course of disease to be made. Patients with NPH at an early stage reported an improvement of their symptoms in the follow-up after a shunt operation in 65% of cases, while 50% of those with advanced-stage NPH reported improvement. Conclusion: The computer- aided infusion test allows a reliable differentiation between patients with NPH and those with cerebral atrophy.

The importance of the intrathecal infusion test in the diagnostics of normal pressure hydrocephalus.

The intrathecal infusion test is a reliable method in diagnosing normal pressure hydrocephalus. Between May 1982 and January 1997 we investigated 200 patients suspected for a normal pressure hydrocephalus (NPH) by carrying out an intrathecal infusion test in a constant flow technique. The resistance to cerebrospinal fluid outflow (Rout) in the intrathecal infusion test was the main criterion for grouping patients into these with normal pressure hydrocephalus or those with cerebral atrophy. A further differentiation into early stage and late stage was made by measuring the compliance (Cp)--this being the secondary criterion. In 107 patients (54%) the diagnosis of a NPH could be confirmed. Of these, 102 patients (95%) underwent a shunt operation. Graduation of NPH and cerebral atrophy following the results of the infusion test in an early stage and an advanced stage allows the conclusion of prognostic evaluations about the course of disease to be made. Patients with a NPH in an early stage are reporting in the follow up about an improvement of their symptoms after a shunt operation in 65 percent of cases and those with an advanced stage NPH in 50 percent. The computer aided infusion test allows a reliable differentiation between patients with NPH and those with cerebral atrophy.

Pressure-dependent flow resistance in craniospinal cerebrospinal fluid dynamics: a calculation model for diagnosis of normal pressure hydrocephalus

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.

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.

Psychophysiology, signs and symptoms of disease the course of normal pressure hydrocephalus

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.

O-29-431 - The intrathecal infusion test as an investigative method in normal pressure hydrocephalus: When should a shunt be inserted?

The almost age-old neuroendoscopy (NE) and neuronavigation (NN) in its twenties independently and indisputably have proved their high value as neurosurgical armamentarium and became even indispensable in some pathologies. However, nowadays the effectiveness of their simultaneous and combined application still is a matter of debate. The purpose of our pilot international, questionnaire-based survey was to assess the position of the opinion leaders in the field of neuroendoscopy worldwide toward the neuronavigational neuroendoscopy (NNNE).Within 3 months, a questionnaire with 17 questions was emailed repeatedly to 55 leading academic neuroendoscopic neurosurgeons from 50 institutions in 24 countries. The questionnaire covered aspects of personal and institutional experience in NE, NN, and NNNE, the most frequently treated pathologies by NNNE as well as inquiring the neurosurgeons' opinion for the importance and future of NNNE.Forty-one questionnaires were returned (response rate = 74.6%). Six questionnaires were excluded because of incomplete or incorrect answers, leaving in the survey 35 respondents from 35 institutions in 18 countries. The less experienced neurosurgeons rely in higher degree on NNNE. Most frequently, NNNE is performed for hydrocephalus (procedures other than third ventriculostomy), transsphenoidal surgery, tumor biopsy, and cyst fenestration. Regardless their neurosurgical and NE experience, more than 75% of the respondents state that NNNE extends the range of neuroendoscopic procedures in their neurosurgical departments.NNNE represents a valuable operative technique with excellent future prospects. NNNE extends the range of neuroendoscopic procedures, transforming some number of patients from “nonoperable” neuroendoscopically to suitable for neuroendoscopy.

Intrathecal infusion test and decrease in shunt revisions and infections.

The intrathecal infusion test leads to a more accurate diagnosis of communicating hydrocephalus, and is useful in identifying those patients with insufficient cerebrospinal fluid (CSF) absorption who are most likely to improve after a shunt operation. Furthermore, shunt function can be evaluated by assessing the CSF absorption of shunt-operated patients in the same way. Some patients do not improve after surgery because of irreversible or shunt-independent neurological and radiological signs, while the postoperative infusion test demonstrates a normal shunt function. The clinical condition and neuroradiological picture of such patients cannot be improved by shunt revision if the implanted shunt already allows a normal CSF outflow. By means of infusion tests the number of patients who need a further operation can be reduced, with a consequent drop in shunt infections, a very welcome aspect especially in pediatric neurosurgery. In our department 298 infusion tests were carried out over a seven-year period, and a decrease in shunt revisions and infections could be observed.

Differentiation of communicating hydrocephalus and presenile dementia by continuous recording of cerebrospinal fluid pressure.

Continuous monitoring of the cerebrospinal fluid pressure and observation of the pressure during intrathecal infusion of normal saline at two rates were performed in patients with communicating hydrocephalus and cerebral atrophy of other causes. Constant or temporarily increased cerebrospinal fluid pressure was observed only in communicating hydrocephalus. Reduction of intracranial pressure by a ventriculoatrial shunt was associated with clinical improvement. The intrathecal infusion test was capable of detecting reduced absorption of cerebrospinal fluid if more than one infusion rate was employed. Using both tests it is easier to determine which patients with communicating hydrocephalus should be treated with a shunt operation.

Resistance to drainage of cerebrospinal fluid: clinical measurement and significance.

By infusing saline intrathecally at a constant rate until a new steady-state cerebrospinal fluid (CSF) pressure is attained, one can estimate clinically the apparent resistance (Ra) to drainage of CSF in mm saline/ml./minute. This intrathecal saline infusion test (ITSIT) was performed 36 times on 29 patients with diverse intracranial problems, and the results were analysed and, in most cases, compared with the pneumoencephalogram and the isotope cisternogram. The ITSIT is a safe, simple test to estimate Ra, but factors which are difficult to control (occult leaks from the subarachnoid space; independent fluctuations of CSF pressure) limit its reliability and clinical usefulness. If closely correlated with the clinical syndrome, the pneumoencephalogram, and the isotope cisternogram, an ITSIT may identify decisively the patient who needs a shunt. In addition the ITSIT offers another method by which to investigate the pathophysiological mechanisms of the various states of intracranial hypertension. Results from the test performed on four patients with intracranial hypertension of unknown cause (pseudotumor cerebri) suggest that the underlying mechanism in this condition is probably an impediment to normal CSF drainage.