Doppler flow velocities in children with controlled hydrocephalus: reference values for the diagnosis of blocked cerebrospinal fluid shunts

Doppler flow velocities in the middle cerebral artery of children with blocked cerebrospinal fluid shunts show changes that can be used as a non-invasive method for assessing shunt function. The velocities also change with age, and the purpose of this study was to define a reference range of values for children with controlled hydrocephalus. Flow velocities were measured in 248 asymptomatic children with shunts and an age-reference range was derived. Twenty children were subsequently admitted with suspected shunt malfunction and 11 of these required a shunt revision. On admission 9 of the 11 children requiring operation had Doppler values outside the reference range, whereas none of the children whose symptoms settled without surgery had abnormal values. The reference range will facilitate the use of transcranial Doppler for the assessment of children with suspected shunt malfunction.     

Cerebrospinal fluid and extracellular fluid: their relationship to pressure and duration of canine hydrocephalus

Fifteen greyhound dogs were made hydrocephalic by the transsphenoidal injection of silicone into the basal cisterns at the level of the tentorial incisura. Six of these animals had ventriculocisternal perfusions 4 weeks later and six at 8 weeks, half at 150 and half at 100 mm H₂O. Three 12-week dogs were perfused at 150 mm H₂O. Serial sections of brain from the ependyma of the left frontal horn to the overlying pia were counted for¹⁴C inulin and³H methotrexate uptake. Tissue concentrations of both markers varied indirectly with distance from ependyma and from pia, and varied directly with perfusion pressure. The data indicate that the diffusional pathway between cere-brospinal fluid (CSF) and extracellular fluid (ECF) can be modified by CSF pressure changes, i.e., CSF flows from the ventricles and subarachnoid space into the extracellular space when CSF pressures are raised. Brain uptake of inulin and methotrexate was significantly increased in the dogs made hydrocephalic 4 weeks prior to perfusion, but was less so in the 8-week hydrocephalics. Uptake of the tracers in three 12-week animals was similar to that found previously in normal dogs at elevated pressures. These findings correspond in location and time to the periventricular lucencies that are seen by computed tomography in human subacute hydrocephalus. They are apparently due to pressure-related changes in the volume of the ECF.     

A nonlinear biomechanical model for evaluation of cerebrospinal fluid shunt systems

In view of complications arising from physical properties of cerebrospinal fluid shunts, a biomechanical model of hydrocephalus was set up to study in vivo parameters that may influence their function. These include: intracranial pressure, compliance and pulses, intrathoracic, intra-abdominal, and subcutaneous pressures, and the effects of siphonage and repeated valve flushing. Each of these factors was studied separately upon shunt implantation in the model. Results of testing of a sample lowpressure valve with antisiphon device conformed with consumer information in regard to valve opening pressure and pressure flow measurements. No customer information, however, was supplied concerning the deleterious effects of direct subcutaneous pressure, variable degrees of siphonage, and repeated valve flushing that were demonstrated by the model. Such results indicate that shunts should be similarly tested prior to marketing and implantation in patients.     

Abdominal cerebrospinal fluid pseudocysts

Abdominal cerebrospinal fluid pseudocyst is an infrequent complication of ventriculoperitoneal (VP) shunts. We reviewed ten patients with abdominal pseudocyst. There were five girls and five boys, aged between 4 months and 14 years. The number of shunt procedures prior to the presentation varied between one and five. Only one patient had had a previous shunt infection. No patients had undergone prior abdominal surgery other than VP shunting. The time from the last shunting procedure to the development of abdominal pseudocyst ranged from 3 weeks to 5 years. Presenting symptoms and signs were mainly related to abdominal complaints in all patients. Three patients also had the signs of shunt malfunction. The diagnosis was made by ultrasound in all patients. Shunt infection was determined in six patients. Repositioning of the peritoneal catheter seemed to have a higher rate of recurrence. The diagnosis of abdominal pseudocyst should be considered in VP-shunted patients presenting with abdominal complaints.     

Imaging of cerebrospinal fluid space and movement of hydrocephalus mice using near infrared fluorescence

Abstract We have studied optical imaging of mice cerebrospinal fluid (CSF) space and flow using near infrared (NIR) fluorescence. We applied our method to image CSF space and flow in a mice hydrocephalus model. Hydrocephalus was induced in mice with intracranial injections of transforming growth factor. Hydrocephalic and control mice were imaged using our NIR fluorescence imaging system. Hydrocephalic mice showed diminished intracranial CSF flow. Our system is sufficient to show altered CSF flow in a mouse hydrocephalus model. Optical imaging using near infrared is an effective modality to image CSF space and movement.     

Ventriculosubcutaneous shunt for temporary treatment of neonatal post-IVH hydrocephalus: a technical note

A technique for temporary ventricular drainage using a subcutaneous pouch is described for use in neonatal hydrocephalus after intraventricular hemorrhage. The advantages include continuous, valve-regulated ventricular decompression, no exposed tubing, avoidance of electrolyte imbalance and of the loss of CSF, obviation of the need for repeated tapping, and the ability to convert to a peritoneal shunt on an elective basis.     

Idiopathic normal-pressure hydrocephalus,cerebrospinal fluid biomarkers,and the cerebrospinal fluid tap test

Cerebrospinal fluid (CSF) biomarkers, including soluble amyloid β-42 (Aβ-42) and phosphorylated-tau (P-tau), reflect core pathophysiological features of Alzheimer’s disease (AD). AD is frequently a concomitant pathology in older patients with idiopathic normal-pressure hydrocephalus (iNPH), and somewhat similar altered CSF dynamics exist in both AD and iNPH. We therefore investigated relationships between lumbar CSF biomarkers Aβ-42 and P-tau and clinical parameters in iNPH patients, along with differences in these biomarkers between CSF tap test (CSFTT) responders and non-responders. Thirty-one iNPH patients (14 CSFTT responders and 17 CSFTT non-responders) were included in the final analysis. We found lower CSF Aβ-42 correlated with poor cognitive performance (r = 0.687, p < 0.001 for Korean Mini Mental State Examination; r = 0.568, p = 0.001 for Frontal Assessment Battery; r = −0.439, p = 0.014 for iNPH grading scale [iNPHGS] cognitive score; r = −0.588, p = 0.001 for Clinical Dementia Rating Scale), and lower CSF P-tau correlated with gait dysfunction (r = −0.624, p < 0.001 for Timed Up and Go Test; r = −0.652, p < 0.001 for 10 meter walking test; r = −0.578, p = 0.001 for Gait Status Scale; r = −0.543, p = 0.002 for iNPHGS gait score). In subgroup analysis, CSF P-tau/Aβ-42 ratios were significantly higher in CSFTT non-responders compared to responders (p = 0.027). Two conjectures are suggested. One, CSF biomarkers may play different and characteristic roles in relation to different iNPH symptoms such as cognition and gait. Two, comorbid AD pathology in iNPH patients may affect the response to the CSFTT. Larger studies using combinations of other biomarkers associated with AD would be necessary to evaluate these hypotheses.     

The effect of large doses of dexamethasone on the cerebrospinal fluid pressure in patients with supratentorial tumors

Summary The effect of large doses of dexamethasone (80 mg) on the cerebrospinal fluid pressure (CSFP) was investigated with continuous lumbar CSFP measurement over 24h in 10 patients with supratentorial cerebral tumors and clinical signs of elevated intracranial pressure. There was a further slight rise in CSFP with an unchanged pressure pattern in the course of observation of the untreated control group. A marked lowering of CSFP was observed within 6h after initial intravenous administration of dexamethasone to seven of the treated patients. In four of the treated patients an unequivocal and in five only a moderate CSFP lowering was measured at the end of the registration. One patient had a slight rise in pressure. The plateau waves of all the patients treated decreased in height, frequency and duration within the first hours, while fluctuations in pressure level and CSFP amplitude were reduced.

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Zusammenfassung Mit der kontinuierlichen lumbalen Liquordruckmessung wurde bei 10 Patienten mit supratentoriellen Hirntumoren und klinischen Zeichen intrakranieller Drucksteigerung über 24 Std die Wirkung hoher Dosen Dexamethason (80 mg) auf den Liquordruck (CSFP) untersucht. Während es bei der Kontrollgruppe (unbehandelte Patienten) im Laufe der Registrierung zu einem weiteren leichten CSFP-Anstieg bei unverändertem Druckmuster kam, wurde bei 7 der behandelten Patienten innerhalb 6 Std nach initialer intravenöser Dexamethasongabe eine deutliche CSFP-Senkung beobachtet. Bei 4 der behandelten Patienten wurde zum Ende der Registrierung eine eindeutige, bei 5 eine nur mäßige CSFP-Senkung gemessen. 1 Patient wies einen leichten Druckanstieg auf. Bei allen behandelten Patienten nahmen die Plateauwellen innerhalb der ersten Stunden an Höhe, Häufigkeit und Dauer ab, Druckniveauschwankungen und Liquordruckamplituden verringerten sich.

     

The concentrations of xanthine and hypoxanthine in cerebrospinal fluid as therapeutic guides in hydrocephalus

Xanthine, hypoxanthine, and total oxypurine levels were determined in the cerebrospinal fluid of 18 hydrocephalic patients and 8 healthy controls by high-performance liquid chromatography (HPLC). Eight of the hydrocephalic patients were self-compensated and 10 had shunts implanted during the course of the study. The mean xanthine, hypoxanthine, and total oxypurine levels in the normal children were 5.20, 5.94 and 11.29 mol/l, respectively. In self-compensated hydrocephalics these levels were respectively 6.06, 6.50 and 12.57 mol/l. In noncompensated hydrocephalics, they were 11.40, 10.79 and 22.19 mol/l. The differences between the latter group and the first two are statistically significant (P<0.001). Fifteen days after implantation of shunts in the noncompensated hydrocephalics, the mean xanthine levels had fallen to 4.61 mol/l, the mean hypoxanthine levels to 5.03 mol/l, and the mean total oxypurine levels to 9.64 mol/l. The change is statistically significant (P<0.001). In light of these findings we propose that xanthine, hypoxanthine, and total oxypurine levels be used in cases of hydrocephalus as guides for therapeutic action and to monitor progress.     

Non-invasive assessment of cerebrospinal fluid flow dynamics using phase-contrast magnetic resonance imaging in communicating hydrocephalus

This work aims to evaluate the changes in cerebrospinal fluid (CSF) hydrodynamics in patients diagnosed with communicating hydrocephalus. Besides, we establish the relationship between CSF flow dynamic parameters on the midbrain aqueduct and intracranial pressure (ICP). CSF hydrodynamics analysis was performed using Phase-Contrast Magnetic Resonance Imaging (PC‐MRI) techniques on the midbrain aqueduct of 41 patients diagnosed with communicating hydrocephalus and 22 healthy volunteers. The correlation between CSF average flow in the midbrain aqueduct and intracranial pressure measured by Lumbar Puncture (LP) was assessed in patients with hydrocephalus. Pearson correlation coefficient was used to establish the correction between the average CSF flow of midbrain aqueduct and ICP. CSF dynamic parameters of the midbrain aqueduct in hydrocephalus patients, including peak positive velocity (7.348 cm/s), average velocity (0.623 cm/s), average flow (50.799 mm³/s), and regions of interest (ROI) area (9.978 mm²) were significantly higher than in the healthy controls (p < 0.05). This was after adjusting the age, gender, heart rate, systolic blood pressure, diastolic blood pressure, and body mass index. However, only the peak negative velocity of the midbrain aqueduct did not significantly differ between the groups (p = 0.209). A positive correlation was noted between the average flow (AF) of the midbrain aqueducts and ICP in hydrocephalus patients (y (AF) = 0.386× (ICP)−33.738, r = 0.787, p < 0.05). Reference data of CSF flow dynamic parameters was obtained through the PC-MRI in middle-aged healthy volunteers and communicating hydrocephalus patients. Although the sample size was constrained, this study has significant contributions. For instance, a significant correlation was noted between the average CSF flow of the aqueduct and ICP. This therefore provides a reference for clinicians to monitor ICP in patients with hydrocephalus.     

Cerebrospinal fluid shunt malfunction signaled by new or recurrent seizures

We have observed two patient groups with seizure activity as the primary presentation of shunt malfunction. Eight patients had a first-time seizure, and seven patients had a history of prior seizures, none more recently than 1 year prior to the seizure recurrence. Five of seven patients with prior seizures who seized were on anticonvulsant medication, three of these seven patients had therapeutic anticonvulsant levels. Shunt malfunction was diagnosed via a combination of tests. The electroencephalograms of nine patients were diffusely abnormal with regions of slowing and focal spike activity. Seizure activity stopped in all patients after preoperative stabilization with anticonvulsant medication and shunt revision. These 15 patients represent 2% of all patients treated for shunt malfunction during a 3-year period. The assessment of new or recurrent seizure activity in a previously stable shunted patient should include evaluation of shunt function whatever the anticonvulsant levels.     

A unifying theory for the definition and classification of hydrocephalus

If the cerebrospinal fluid (CSF) is considered to be all the fluid (liquid), other than blood or the derivatives of its breakdown, that is normally contained within the brain, its cavities, and its spaces, this could be regarded as brain fluid in its most elemental form. Pathological increases in intracranial CSF volume, independent of hydrostatic or barometric pressure, then, could be considered a definition of hydrocephalus. The observation of significant episodic variation in intracranial pressure (ICP) suggests the necessity of substituting the concept of time-related pressure variations for the older one of level of pressure in patients with defective ICP control mechanisms. It has been assumed that the subarachnoid channels are the first CSF compartment to dilate in response to the hydrocephalic process, reducing the CSF pressure and thereby establishing an equilibrium. When the equilibrium is disturbed, with progressive dilation of the subarachnoid channels, the increase in CSF pressure is transmitted to the ventricular system, resulting in its dilation (extraprenchymal hydrocephalus). Progressive ventricular dilation causes cerebral edema (intraparenchymal hydrocephalus) and obliterates the subarachnoid spaces as the hemispheres are compressed against the dura, resulting in apparent internal hydrocephalus in the absence of external hydrocephalus. Thus, subarachnoid space or ventricular dilation occur as a result of intermittent increases in extraparenchymal CSF volume: the primary pressure force emanating from the subarachnoid and subdural spaces and from the intraventricular compartment. Hydrocephalus, therefore, may be present in a child who does not yet have dilated ventricles but in whom both CSF volume and pressure are increased. Thus, it becomes obvious that the term internal hydrocephalus is of little significance, since increases in intraparenchymal fluid-cerebral edema-cause the same volumetric changes as increases in intraventricular fluid volume. I suggest that hydrocephalus is a pathologic increase in intracranial CSF (brain fluid) volume, whether intra- or extraparenchymal, independent of hydrostatic or barometric pressure. It may be classified as (1) intraparenchymal (cerebral edema) and (2) extraparenchymal, with the extraparenchymal types subclassified into subarachnoid, cisternal, and intraventricular forms.Presented at the Consensus Conference: Hydrocephalus '92, Assisi, Italy, 26–30 April 1992     

Value of precraniotomy shunts in children with posterior fossa tumours

Seventy children with posterior fossa tumours treated over a period of 6 1/2 years were studied. Most patients presented in the late stage of disease. Sixty-four required insertion of a precraniotomy shunt for one or more of the following: persistent vomiting, severe headache, dehydration, poor general condition, failing vision, altered sensorium, marked periventricular lucency, and brain stem involvement deferring total removal of the tumour. Insertion of precraniotomy shunt improved the general condition and signs and symptoms of increased intracranial pressure. It also provided a lax brain during definitive surgery and a smooth postoperative course. Shunt-related complications, consisting of block and/or infection, were observed in 21 patients. It was concluded that precraniotomy shunt is important in the management of children with posterior fossa tumours in developing countries where these patients present in the late stage of disease.     

Rationale and methodology of the multicenter pediatric cerebrospinal sluid shunt design trial

Cerebrospinal fluid shunt failure remains a common and at times overwhelming problem in pediatric patients with hydrocephalus. Two new shunt valve designs, the Orbis-Sigma (Cordis Corporation, Miami, Florida) and the Delta valve (PS Medical, Goletta, California), have flow/pressure characteristics dramatically different from those of standard differential pressure valves which have been used for over three decades. Both new designs reduce the siphoning effect in the upright position, and have been reported to reduce shunt failure rates in uncontrolled series, allegedly due to reduction in shunt overdrainage. Most mechanical shunt failure in the first 2 years after implantation is due to proximal shunt obstruction, overdrainage, and loculated ventricles. By reducing the incidence of slit ventricles associated with standard valves, both new designs could be envisioned as reducing the early mechanical complications. The improved results with both new valves could, however, also be to a large extent due to other confounding effects of shunt surgery, including patient selection, surgical technique, and specific configuration of the components of the shunt other than the valve. There are also theoretical reasons why these valve designs might be worse than their predecessors, including the narrow orifice and high resistance of the Orbis-Sigma, and the flexible membrane of the siphon control portion of the Delta valve, which may increase the ventricular pressure in the upright position or become blocked by encasing scar tissue. For this reason a randomized trial is required to determine efficacy, and a standard differential pressure valve is required as the control desing. A significant reduction in early shunt failure would dramatically improve the morbidity and mortality of pediatric hydrocephalic patients, as well as providing substantial savings to the health care system. Failure to determine any difference would focus attention on other issues surrounding shunt surgery, such as patient characteristics or surgical technique. The Pediatric Hydrocephalus Treatment Evaluation Group comprises: J. M. Drake J Kesrle, F. Boop, Little Rock; D. Cochrane, Vancouver; S. Haines, Minneapolis; C Sainte-Ros, Paris; S. Schiff, Washington, D.C.; P. Steinbok, Vancouver     

Cerebral fluid edema: an unusual complication of ventriculoperitoneal shunts

Introduction A case of accumulation of CSF into the brain parenchyma simulating a brain tumor, secondary to an obstructed ventriculoperitoneal shunt, is presented. Until now, only seven cases of this rare complication have been described.Case report Magnetic resonance showed an expansive, low-density intracranial lesion on the right frontal and parietal lobe. This mass was biopsied, but no tumor was found and the diagnosis was brain edema.Conclusion The mistake in the diagnosis was due to the clinical symptoms and to the MR images.     

Effect of endoscopic third ventriculostomy on cerebrospinal fluid pressure in the cerebral ventricles

We aimed to show how endoscopic third ventriculostomy (ETV) treatment may affect cerebrospinal fluid (CSF) flow dynamics in hydrocephalus, with and without aqueductal stenosis. Hydrocephalus is a neurological disorder which is characterized by enlarged brain ventricles. The periodic motion of CSF flow as a function of the cardiac cycle was prescribed as the inlet boundary condition at the foramen of Monro, and ETV was modeled as a 5 mm diameter hole in the anterior wall of the third ventricle. The results show that ETV reduces the pressure in the ventricles by nine-fold in the model with aqueductal stenosis, and three-fold in the model without aqueductal stenosis. More importantly, ETV changes the temporal characteristics of the CSF pressure waveform in the model without aqueductal stenosis, such that there is higher pressure in the ventricle during diastole. This study suggests that changes in the temporal characteristics of the CSF pressure waveform in the ventricles may be the reason why ETV treatment is not effective for hydrocephalus without aqueductal stenosis.     

Prediction of Shunt-Dependent Hydrocephalus after Primary Supratentorial Intracerebral Hemorrhage with a Focus on the Influence of Craniectomies

ObjectiveHydrocephalus after intracerebral hemorrhage (ICH) is known to be related to poor prognosis and mortality. We analyzed predictors of permanent hydrocephalus in the patients with surgically treated supratentorial ICH. MethodsFrom 2004 to 2019, a total of 414 patients with surgically treated primary supratentorial ICH were included. We retrospectively analyzed age, sex, preexisting hypertension and diabetes, location and volume of ICH, presence and severity of intraventricular hemorrhage (IVH), and type of surgery. ResultsForty patients (9.7%) required shunt surgery. Concomitant IVH was higher in the ‘shunt required’ group (92.5%) than in the ‘shunt not required’ group (67.9%) (p=0.001). IVH severity was worse in the ‘shunt required’ group (13.5 vs. 7.5, p=0.008). Craniectomy (47.5%) was significantly high in the ‘shunt required’ group. According to multivariable analysis, the presence of an IVH was 8.1 times more frequent and craniectomy was 8.6 times more frequent in the ‘shunt required’ group. In the comparison between craniotomy and craniectomy group, the presence of an IVH was related with a 3.9 times higher (p=0.033) possibility and craniectomies rather than craniotomies with a 7-times higher possibility of shunt surgery (p<0.001). Within the craniectomy group, an increase in the craniectomy area by 1 cm² was correlated with a 3.2% increase in the possibility of shunt surgery (odds ratio, 1.032; 95% confidence interval, 1.005-1.061; p=0.022). ConclusionPresence of IVH, the severity of IVH and decompressive craniectomy were related to the development of shunt dependent hydrocephalus in the patients with ICH. The increasing size of craniectomy was related with increasing rate of shunt requirement.     

Silicone oil-induced hydrocephalus in the rabbit

Hydrocephalus was induced in adult rabbits by injecting silicone oil into the cisterna magna. Mean intracranial pressure was significantly elevated for approximately 36 h post-injection, during which time maximal ventricular dilatation was attained. Stretching and compression of periventricular tissue and capillaries accompanied dilation of the lateral ventricles. Ventricular dilation promoted mitotic activity among the periventricular astroglia. Ventriculomegaly altered the metabolism of the monoamine neurotransmitters in the cortex, hippocampus, diencephalon, hypothalamus, and brainstem. Ischemic injury to neurons of the hippocampal formation, particularly the dentate gyrus, was observed when hydrocephalus had persisted for more than 4 weeks. Cerebrospinal fluid shunting effectively reversed the neuropathologic changes only when done in the early stages of hydrocephalus. When hydrocephalus persisted for 8 weeks, rapid reversal of changes in the ependyma and periventricular capillaries was prevented largely by periventricular gliosis.     

Evaluation of cerebrospinal fluid shunt function in hydrocephalic children using 99mTc-DTPA

The increasing numbers and survival of children with shunt-treated hydrocephalus make it mandatory to refine the methods for cerebrospinal fluid (CSF) shunt function evaluation. Radionuclide shuntography with ^99mTc-DTPA, which has proved to be a safe and effective method, was performed in eight children with suspected CSF-shunt dysfunction. Characteristic shuntography patterns were found for proximal and distal CSF-shunt catheter obstruction as well as for overdrainage and normal CSF-shunt function. Shuntography contributed to the explanation of suspected CSF-shunt dysfunction in all children investigated.     

脑脊液置换术在蛛网膜下腔出血患者中的应用

目的探讨脑脊液置换术对蛛网膜下腔出血(SAH)患者脑血管痉挛、脑积水的防治作用及缓解头痛的疗效,并评估其安全性。方法将颅内动脉瘤破裂引起的SAH患者96例分为保守治疗组(对照组)、脑脊液置换组(置换组)及颅内动脉瘤填塞术后脑脊液置换组(治疗组),比较3组脑血管痉挛、脑积水发生率和头痛缓解时间等方面的差异及再出血发生率。结果置换组及治疗组脑血管痉挛和脑积水并发症的发生率较对照组明显降低(PO.05);头痛缓解时间较对照组明显缩短(P0.05);治疗组及对照组再出血发生率较置换组明显降低(PO.05)。结论脑脊液置换术对预防SAH患者的脑血管痉挛、脑积水有效,可明显缩短患者头痛缓解时间,但为降低再出血发生率,脑脊液置换术应在动脉瘤填塞术后进行。