bluuebunny/crossref_metadata_2025_split huggingface dataset:
Management of patients with normal-pressure hydrocephalus by using lumboperitoneal shunt system with the Codman Hakim programmable valve
Authors: Chang Chia-Cheng , Kuwana Nobumasa , Ito Susumu 
Published: January 2008

Thirty-two patients with normal-pressure hydrocephalus were managed using the lumboperitoneal (LP) shunt system in which the Codman Hakim programmable valve was utilized. The initial opening pressure was set at 100 mm H2O in three cases, 80 mm H2O in two, 70 mm H2O in three cases, 50 mm H2O in 23, and 30 mm H2O in one case (mean pressure 57.8 mm H2O). In 12 patients the valve pressure required reprogramming. The final valve pressure was 30 mm H2O in four cases, 50 mm H2O in 19, 70 mm H2O in three, 80 mm H2O in one, 100 mm H2O in two, 130 mm H2O in one, 140 mm H2O in one, and 170 mm H2O in one case (mean 62.5 mm H2O). Lumboperitoneal shuntography was performed in five patients by injection of contrast medium into the prechamber. In two patients a shunt obstruction developed between the valve and the lumbar catheter. Complications occurred in eight patients. Low-pressure symptoms such as headache and vomiting were observed in four patients but disappeared after increasing the valve pressure. One patient, whose shunt pressure was set at 50 mm H2O developed a slight asymptomatic subdural effusion, which resolved after increasing the valve pressure to 100 mm H2O. Convulsions developed in two aged patients but were easily controlled with anticonvulsant medication. Surgery-related wound infection was observed in one patient.
The major advantage in the use of this valve is the ability to modify the pressure noninvasively. Another important advantage of the LP shunt system in which this valve is incorporated is the lower pressure of 30 mm H2O that can improve symptoms caused by underdrainage of cerebrospinal fluid.
Response of cerebral blood flow and cerebrovascular reactivity to acetazolamide in patients with dementia and idiopathic normal-pressure hydrocephalus
Authors: Chang Chia-Cheng , Kuwana Nobumasa , Ito Susumu , Ikegami Tadashi 
Published: January 2008

The responses of cerebral blood flow (CBF) and cerebrovascular reactivity (CVR) to administration of acetazolamide were investigated in 16 patients with dementia and ventriculomegaly to clarify the cerebral hemodynamics in patients with idiopathic normal-pressure hydrocephalus (NPH).
The mean CBF velocity in the whole brain was measured by the Patlak plot method by using technetium-99m hexamethylpropyleneamine oxime single-photon emission computerized tomography. The CVR values were obtained from the response to administration of 500 mg of acetazolamide and calculated as the percentage of change from the baseline mean CBF value. The mean CBF value was significantly reduced (p < 0.01) in six patients with (35.2 ± 5 ml/100 g/minute) and 10 patients without (33.5 ± 2.8 ml/100 g/minute) NPH compared with the age-matched normal controls (40.8 ± 3.2 ml/100 g/minute), showing no significant difference. The CVR was significantly impaired in patients with NPH (0.8 ± 1.7%; p < 0.001), whereas in patients without NPH preserved CVR (11.3 ± 3%) was demonstrated compared with the normal controls (14.7 ± 1.1%). In patients with NPH a significantly lower CVR (p < 0.001) was shown than in those without NPH. The CVR significantly increased (p < 0.001) after placement of a shunt in patients with NPH.
Reductions in both CBF and CVR may be diagnostic indicators of NPH in patients with dementia in whom ventriculomegaly is present. In patients with dementia and idiopathic NPH both reduced CBF and extremely impaired CVR are shown. The results of the present study suggest that ischemia due to the process of NPH is responsible for the reduction of CBF and manifestation of symptoms in patients with idiopathic NPH.
Altered diffusion and perfusion in hydrocephalic rat brain: a magnetic resonance imaging analysis
Authors: Massicotte Eric M. , Buist Richard , Del Bigio Marc R. 
Published: January 2008

It can be inferred from data published in the literature that brain compression occurs in the early stages of acute hydrocephalus and that drainage of extracellular waste products is impaired. The authors hypothesized that compression of the cortical extracellular compartment will alter water distribution and retard the diffusion of fluid in the hydrocephalic brain.
Using magnetic resonance imaging proton diffusion, blood perfusion, and T1 and T2 relaxation times were determined in adult rat brain prior to, and 1 and 8 days following induction of hydrocephalus by using kaolin injection. Five anatomical regions of interest were studied. The striatum, dorsal cortex, and lateral cortex were shown to exhibit decreased T2 and apparent diffusion coefficient (ADC) values but no change in perfusion. Examination of white matter demonstrated an initial decrease in ADC followed by a significant increase. The T2 relaxation times increased and perfusion decreased progressively from 1 to 8 days.
Acute experimental hydrocephalus causes compression of gray matter, perhaps associated with reduction in total water, which impairs diffusion of protons in the tissue. White matter compression and hypoperfusion precede the development of edema. These findings have importance for understanding the neurochemical changes that occur in hydrocephalic brains.
Incidence and management of subdural hematoma/hygroma with variable- and fixed-pressure differential valves: a randomized, controlled study of programmable compared with conventional valves
Authors: Carmel Peter W. , Albright A. Leland , Adelson P. David , Canady Alexa , Black Peter , Boydston William , Kneirim David , Kaufman Bruce , Walker Marion , Luciano Mark , Pollack Ian F. , Manwaring Kim , Heilbrun M. Peter , Abbott I. Richmond , Rekate Harold 
Published: January 2008

Shunt systems with differential pressure valves are prone to the complications of overdrainage. A programmable valve permits adjustment of the opening pressure of the valve. In this paper the authors report the incidence of subdural fluid collections in a randomized trial of programmable compared with conventional valves, and they describe methodologies used in management of this complication.
A multiinstitutional, prospective, randomized trial of the Codman Hakim programmable valve and conventional fixed-pressure valves was undertaken. Two classes were defined: “new” and “replacement” valves. Randomization of the type of valve in each group was performed at each study site. Clinical and radiological studies were required at fixed intervals over a 104-week period. All complications were reported. The experimental valves were required to be reprogrammed after magnetic resonance imaging studies, but all other decisions regarding pressure setting were left to each investigator.
Three hundred seventy-seven patients were randomized; 194 were treated with a programmable valve and 183 with a fixed-pressure valve. The two groups were statistically similar in demographic composition, as were the “new” and “replacement” categories. The investigators made 540 valve pressure changes (five per patient; range one-41 changes). More than half of the reprogramming adjustments were made in the first 3 months postplacement; 70% were made within 6 months. More than half of all reprogramming adjustments were required in a group of 30 patients.
Four treatment modalities were observed: 1) 30% of the fluid collections resolved spontaneously (25% in the patients with programmable valves and 36.3% in those with conventional valves) and were largely found to be hygromas in infants and children; 2) four subdural fluid collections were unresolved and under observation; 3) the subdural hematoma was drained and the shunt removed (in 8.3% of patients with the programmable valve and 36.3% of those with the control valve); 4) the pressure of programmable valve was raised in 58% of patients (seven of 12), and this increase in opening pressure was a feature used by investigators to affect treatment.
There was no significant difference in the incidence of subdural fluid collections between the programmable and fixed-pressure valve treatment groups. The programmable feature provided a considerable advantage in treatment when subdural collections occurred.
Intracranial hypertension and cerebral perfusion pressure: influence on neurological deterioration and outcome in severe head injury
Authors: Juul Niels , Morris Gabrielle F. , Marshall Sharon B. , _ _ , Marshall Lawrence F. 
Published: January 2008

Object
Recently, a renewed emphasis has been placed on managing severe head injury by elevating cerebral perfusion pressure (CPP), which is defined as the mean arterial pressure minus the intracranial pressure (ICP). Some authors have suggested that CPP is more important in influencing outcome than is intracranial hypertension, a hypothesis that this study was designed to investigate.

Methods
The authors examined the relative contribution of these two parameters to outcome in a series of 427 patients prospectively studied in an international, multicenter, randomized, double-blind trial of the N-methyl-D-aspartate antagonist Selfotel. Mortality rates rose from 9.6% in 292 patients who had no clinically defined episodes of neurological deterioration to 56.5% in 117 patients who suffered one or more of these episodes; 18 patients were lost to follow up. Correspondingly, favorable outcome, defined as good or moderate on the Glasgow Outcome Scale at 6 months, fell from 67.8% in patients without neurological deterioration to 29.1% in those with neurological deterioration. In patients who had clinical evidence of neurological deterioration, the relative influence of ICP and CPP on outcome was assessed. The most powerful predictor of neurological worsening was the presence of intracranial hypertension (ICP >/= 20 mm Hg) either initially or during neurological deterioration. There was no correlation with the CPP as long as the CPP was greater than 60 mm Hg.

Conclusions
Treatment protocols for the management of severe head injury should emphasize the immediate reduction of raised ICP to less than 20 mm Hg if possible. A CPP greater than 60 mm Hg appears to have little influence on the outcome of patients with severe head injury.
The importance of shunt valve position in flow characteristics of the Medtronic PS Medical Delta valve
Authors: Francel Paul C. , Stevens F. Alan , Tompkins Paul , Pollay Michael 
Published: January 2008

This study was conducted to document the extent to which flow depends on valve position in relation to head-pressure reference.
Medtronic PS Medical Delta valves (contour model, performance levels 0.5, 1.0, 1.5, and 2.0) were studied in a bench test designed to evaluate flow rates with respect to valve position in relation to the head-pressure reference postion. The valves were connected to an “infinite” reservoir by the standard inlet catheter. An initial head (proximal) pressure was selected for each valve based on package insert data. The position of the inlet catheter tip was fixed at this starting head pressure, thus making the inlet catheter tip position the reference for relative head pressures on the valve assembly. When the valve body is positioned above this level, the effective head pressure is lowered, and when the valve body is positioned below this level, the effective head pressure is raised. Flow was established with the siphon control portion of the valve body located on the same horizontal level as the inlet catheter tip (the reference head pressure or “0” position). A standard silastic catheter was attached to the outlet of the valve, and its length was fixed at 50 cm for all valves (-50 cm H20). The distal end of the outlet catheter was connected to a fraction collector, and 1-minute samples (five replicates) were collected for gravimetric determination of flow rate. The valve assembly was then moved in 1-cm increments through the range of 4 cm above to 8 cm below the head-pressure reference position. Samples were collected from each position (4 cm to -8 cm) relative to the inlet catheter tip. Flow rate, in milliliters/hour, was plotted against both relative position (4 cm to -8 cm) and absolute head pressure (in centimeters of water).
Each of the valves tested was shown to have a linear relationship between flow and position relative to the inlet catheter tip (or absolute head pressure). The average increase in flow per centimeter of displacement of valve from catheter tip was 16.5 ml/hr/cm (range 14.4-17.6 ml/hr/cm). Once the inlet catheter tip is fixed in position, it serves as a pressure reference. Movement of the valve above this level results in a net decrease in effective head pressure, and movement below this position results in a net increase in effective head pressure. Thus, the positioning of shunt valves in locations different from this pressure reference position should be performed only with the knowledge that significant increases in outflow rate may occur when the valve body is positioned lower than the inlet catheter tip. This increase in outflow rate is not the result of siphoning or a defect in the antisiphon device but instead the result of a net increase in effective head pressure.
Dynamic and three-dimensional transcranial sonography studies of an asymptomatic, cerebral convexity arachnoid cyst
Authors: Schlachetzki Felix , Hölscher Thilo , Ullrich O.W. , Kübber M.D. Sabine , Blersch Wendelin , Götz Birgit , Ocklenburg Katrin , Schalke Berthold , Bogdahn Ulrich 
Published: January 2008

Dynamic and three-dimensional transcranial sonography (dTCS and 3D-TCCS) examinations are complementary, noninvasive methods used in the assessment and follow up of patients with cerebrospinal fluid (CSF) circulation disorders.
A 16-year-old female patient who presented with a space-occupying, cerebral convexity arachnoid cyst and recurrent tension-type headache underwent examination for raised intracranial pressure (ICP) by using a standard color-coded duplex sonography system attached to a personal computer–based system for 3D data acquisition. Conventional TCS identified the outer arachnoid membrane of the cyst, which undulated freely after short rotation of the head (“headshake maneuver”). The undulation was documented as a QuickTime movie that is included with this article. A 3D dataset was acquired and, by using a multiplanar reformatting reconstruction algorithm, the authors obtained images with excellent resolution that corresponded to an initial magnetic resonance (MR) imaging study. No differences on dTCS and 3D-TCS were detectable at follow up 9 months later, indicating normal ICP and a stable, benign condition.
The use of 3D-TCCS and dTCS ultrasonography may complement other diagnostic procedures such as MR imaging and, thus, can improve management and therapeutic strategies for patients with CSF circulation disorders. In this report the authors present evidence of the excellent fine resolution and exact reproducibility of reconstructed ultrasound image planes derived from 3D datasets and the additional biomedical information from dynamic imaging.
Efficacy of variable-angle screws in transpedicular fixation
Authors: Arnold Paul M. , Strang Robert D. , Roussel Danielle 
Published: January 2008

The purpose of this study was to evaluate the usefulness and efficacy of variable-angle screws in transpedicular fixation.
Sixteen patients (10 men and six women, age range 44–73 years) underwent a posterior transpedicular fixation procedure in which variable-angle screws were placed at two or more levels. Four patients experienced spinal instability secondary to trauma, 10 patients suffered from degenerative spondylosis requiring fusion, and two patients were treated for spinal metastatic disease. All patients underwent posterior transverse process fusion in which autologous bone was used. In total, 37 vertebral levels were fixed with variable-angle screws placed at 22 levels. Postoperatively all patients were fitted with an external orthosis that was worn for 12 weeks. Serial postoperative plain x-ray films were obtained in all cases. Follow-up periods ranged from 11 to 24 months.
Based on clinical and radiographic data, solid fusion was achieved in 14 of 16 patients. There were two early disconnections of the rod/screw connectors, which were related to errors in technique. With the exception of these disconnections, there were no cases of construct failure. There were no wound infections, and no patient experienced a decline in neurological function as compared with preoperative levels. Both instrumentation systems were easy to use, and the flexibility in trajectory allowed for quicker screw placement and decreased operating room time.
Variable-angle pedicle screws are a safe, useful adjunct to transpedicular fixation, particularly in multisegment fixation and in spines with abnormal alignment.
Analysis of pediatric head injury from falls
Authors: Kim K. Anthony , Wang Michael Y. , Griffith Pamela M. , Summers Susan , Levy Michael L. 
Published: January 2008

The authors conducted a study to describe the incidence and types of fall-related head injury observed at a pediatric trauma center.
We performed a retrospective analysis of all patients under 15 years of age treated for fall-related trauma between 1992 and 1998. Falls were classified as low (< 15 feet) and high level (≥ 15 feet).
Seven hundred twenty-nine cases were identified with a mortality rate of 1.7%. A fall of greater than 15 feet (high-level fall) was associated with a higher mortality rate than low-level falls (2.4% compared with 1.0%, respectively). Ninety-eight patients had sustained a calvarial fracture and 93 experienced a basal skull fracture. Twenty-six patients had suffered a cerebral contusion, 25 a sub-arachnoid hemorrhage, 22 a subdural hematoma, and 12 had an epidural hematoma. Forty-nine patients required surgery for traumatic injuries; of these, 10 underwent craniotomy for evacuation of a blood clot. Height was not predictive of the Glasgow Coma Scale (GCS) score. In all four deaths resulting from a low-level fall there was an admission GCS score of 3, and abnormal findings were demonstrated on computerized tomography scanning. Death from high-level falls was attributable to either intracranial injuries (50%) or severe extracranial injuries (50%).
Intracranial injury is the major source of fall-related death in children and, unlike extracranial insults, brain injuries are sustained with equal frequency from low- and high-level falls in this population. The only cause of mortality from low-level falls was intracranial injury. Trauma triage criteria must account for these differences in the pediatric population.
Prognostic factors in the occurrence of posttraumatic epilepsy after penetrating head injury suffered during military service
Authors: Aarabi Bizhan , Taghipour Musa , Haghnegahdar Ali , Farokhi Majidreza , Mobley Lloyd 
Published: January 2008

In this retrospective study, the authors evaluated confounding risk factors, which are allegedly influential in causing unprovoked posttraumatic epilepsy, in 489 patients from the frontlines of the Iran–Iraq War.
Four hundred eighty-nine patients were followed for 6 to154 months (mean 39.4 months, median 23 months), and important factors precipitating posttraumatic epilepsy were evaluated using uni- and multivariate regression analysis.
One hundred fifty-seven (32%) of 489 patients became epileptic during the study period. The results of univariate analysis indicated a significant relationship between epilepsy and Glasgow Outcome Scale (GOS) score (X2 = 76.49, p < 0.0001, df = 2), Glasgow Coma Scale score at admission (X2 = 19.48, p < 0.0001, df = 3), motor deficit (X2 = 11.79, p < 0.001, df = 1), mode of injury (X2 = 10.731, p < 0.05), transventricular injury (X2 = 6.9, p < 0.008, df = 1), dysphasia (X2 = 5.3, p < 0.02), central nervous system infections (X2 = 5.3, p < 0.02), and early-onset seizures (X2 = 4.1, p < 0.04, df = 1). The results of multivariate analysis, on the other hand, indicated that the GOS score and motor deficit were of greater statistical importance (X2 = 35.24, p < 0.0001; and X2 = 7.1, p < 0.07, respectively). Factors that did have much statistically significant bearing on posttraumatic epilepsy were the projectile type, site of injury on the skull, patient age, number of affected lobes, related hemorrhagic complications, and retained metallic or bone fragments.
Glasgow Outcome Scale score and focal motor neurological deficit are of particular importance in predicting posttraumatic epilepsy after missile head injury.
Evaluating the outcome of severe head injury with transcranial Doppler ultrasonography
Authors: Moreno José A. , Mesalles Eduard , Gener Juan , Tomasa Antonio , Ley Adolfo , Roca Josep , Fernández-Llamazares Jaime 
Published: January 2008

The authors conducted a study to determine the value of transcranial Doppler (TCD) ultrasonography in evaluating the outcome of severely head injured patients and to correlate the TCD values with those obtained from intracranial pressure (ICP) and cerebral perfusion pressure (CPP) monitoring.
The authors conducted a prospective study of 125 patients with severe head injury (Glascow Coma Scale scores of less than 9) who underwent TCD ultrasonography according to the standard technique of insonating the middle cerebral artery (MCA) and measuring the mean blood flow velocity and pulsatility index within the first 24 hours of admission. The ICP and CPP values, as well as other clinical, analytical, and neuroimaging data, were also recorded. After 6 months, outcome was evaluated using the Glasgow Outcome Scale. Moderate disability and complete recovery were considered “good” outcome; death, vegetative state, and severe disability were considered “poor.”
In 67 patients (54%) good outcome was demonstrated whereas in 58 (46%) it was poor. The mean blood flow velocity of the MCA in patients with good outcome was 44 cm/second; in those with poor outcomes it was 36 cm/second (p < 0.003). The mean PI in cases of good outcome was 1 whereas in poor outcome was 1.56 (p < 0.0001). The correlations of ICP and CPP to PI were statistically significant (r2 = 0.6; p < 0.0001).
When performed in the first 24 hours of severe head injury, TCD ultrasonography is valid in predicting the patient’s outcome at 6 months and correlates significantly with ICP and CPP values.