Oclusión congénita del foramen de Monro como causa de hidrocefalia unilateral. A propósito de un caso / Congenital obstruction of the foramen of Monro causing unilateral hydrocephalus. A propos of a case

La hidrocefalia aislada del ventrículo lateral puede ser provocada por la oclusión unilateral del foramen de Monro. Las causas más frecuentes son los tumores de los ventrículos laterales o en el área del tercer ventrículo. La estenosis no tumoral es poco frecuente y puede deberse a patologías inflamatorias, vasculares o congénitas. Se presenta el caso de un recién nacido a término diagnosticado prenatalmente de hidrocefalia unilateral. Tras el parto se confirmó en las sucesivas ecografías la dilatación ventricular unilateral motivo por el cual se indicó el tratamiento quirúrgico. El paciente fue sometido a la fenestración del foramen de Monro y septostomía por vía endoscópica, con buena evolución clínica y reducción del tamaño ventricular. Los hallazgos intraoperatorios demostraron la obstrucción por una membrana del foramen de Monro derecho. Se puede conseguir un tratamiento adecuado mediante neuroendoscopia, evitando implantar derivaciones ventriculares (AU)

Isolated hydrocephalus of the lateral ventricle may result from unilateral occlusion of the foramen of Monro. The most common causes are tumours of the lateral ventricles or in the area of the third ventricle. Non-tumoural stenosis of the foramen is rare and can be due to inflammatory, vascular or congenital conditions. A full-term infant was prenatally diagnosed with unilateral hydrocephalus. After birth, progressive unilateral ventricular dilatation was confirmed in successive ultrasounds so surgery was indicated. The patient underwent endoscopic fenestration of the foramen of Monro and septostomy with good postoperative clinical evolution and reduction of ventricular size. Intraoperative findings demonstrated membranous obstruction of the right foramen of Monro. A successful treatment can be accomplished through a neuroendoscopic approach avoiding the use of ventricular shunts (AU)

Transcranial access using fluoroscopic flat panel detector CT navigation.

FPCT and navigation software on contemporary fluoroscopic units perform imaging of a quality comparable with conventional CT. They can accurately guide percutaneous procedures, providing live instrument visualization and the capability to re-image without patient transfer. FPCT navigation was used in the placement of a ventricular drain in a 62-year-old woman for subarachnoid-related hydrocephalus by using an otherwise standard bedside technique. Ventriculostomy catheter placement was technically successful without complication with a catheter at the foramen of Monro.

Additive value of nuclear medicine shuntograms to computed tomography for suspected cerebrospinal fluid shunt obstruction in the pediatric emergency department.

OBJECTIVE: To measure the predictive value of nuclear medicine studies (cerebrospinal fluid [CSF] shuntograms) and radiographic studies (computed tomographic [CT] scans) in a cohort of children undergoing evaluation for suspected shunt obstruction in a tertiary care pediatric emergency department (ED). METHODS: A retrospective chart review was conducted on patients younger than 18 years who presented to the pediatric ED of the Children's Hospital of Western Ontario and had both CT of the head and a CSF shuntogram ordered by the attending pediatric emergency medicine physician between December 1998 and April 2003 because of suspected shunt obstruction. RESULTS: A total of 69 patients were evaluated for suspected shunt obstruction in the ED during this period with both a CT and a CSF shuntogram. Twenty-seven patients (39.1%) subsequently required corrective surgery for suspected shunt obstruction that was confirmed intraoperatively. The CT scans showed abnormalities suggestive of CSF shunt obstruction in 21 of the patients who required surgery (sensitivity, 77.8%; negative predictive value, 82.4%), whereas the CSF shuntograms showed abnormalities suggestive of CSF obstruction in 25 of the patients who required surgery (sensitivity, 92.6%; negative predictive value, 92.6%). The CT scans and the shuntograms combined revealed abnormalities suggestive of CSF shunt obstruction in 26 of the 27 patients who required surgery (sensitivity, 96.3%; negative predictive value, 97.4%). CONCLUSIONS: Over one third of pediatric ED patients evaluated with CT and CSF shuntograms required surgical management. Sensitivity was increased with CT and CSF shuntogram compared with CT alone. Prospective studies are required to assess the use of radiographic and nuclear medicine tests for the shunt evaluation in conjunction with the development of a clinical prediction rule for the pediatric emergency physician.

A technique for long-term implantation of a microcatheter into the third ventricle of post-pubertal Chinese Meishan pigs based on ventriculography.

The objectives of this study were to implant a microcatheter into the third ventricle of post-pubertal Chinese Meishan pigs, and to maintain the microcatheter for a long time without causing stress. Fourteen pigs (45-60 kg BW) were used. Each pig was anesthetized and the head was orientated on the stereotaxic apparatus. A radiopaque dye was placed into the ventricle via a guide cannula inserted 3.5 mm forward of the bregma. A microcatheter was inserted into the third ventricle using ventriculography, and fixed with dental cement to a metal-mesh protector and screw anchors embedded into the skull. The opposite end of the microcatheter was externalized from the dorsal neck so that corticotropin-releasing hormone (CRH) could be injected easily. Simultaneously, a catheter was fitted in the jugular vein, and the free end of the catheter was externalized from the dorsal neck. Microcatheter-implanted pigs showed a normal progesterone concentration profile, and a constant cortisol level during at least two estrous cycles. Furthermore, intracerebroventricular injections of CRH (25 microg/500 microl) resulted in an increased plasma cortisol concentration (P < 0.05). Thus, the technique developed in this study enables us to approach the third ventricle in post-pubertal freely-moving pigs effectively over a long time, without causing stress.

Rapid computed tomography technique to measure ventricular volumes in the child with suspected ventriculoperitoneal shunt failure I. Validation of technique with a dynamic phantom.

OBJECTIVES: Assessment of ventricular volume change is critical and can be difficult in the child with suspected shunt failure. Objective techniques described to measure ventricular volumes have used limited anatomic sampling or have been computationally intensive. Phantoms used to evaluate these techniques have used static volumes. The purpose of this study was to construct a computed tomography (CT) phantom to simulate changing ventricular volumes and to evaluate a new program to measure volumes. METHODS: The phantom is 5 Foley catheters embedded in gelatin. The balloons were filled and then scanned at 15-mL increments from 0-300 mL. The program measures the voxels of specified density within a larger volume created by applying a region of interest to a stacked volume. Calculated volumes and percent changes were compared with actual volumes and percent changes. RESULTS: Calculated volumes were consistently 7%-9% (mean: -7.8%) less than actual injected volumes across the entire 0- to 300-mL range. For true changes between -50% and +50%, all calculated changes were within +/-2.5% points of true percent change; for true changes between +50% and +100%, all calculated changes were within +/-5% points of true percent change. CONCLUSIONS: A dynamic CT phantom simulating changing ventricular volumes can be constructed from readily available materials. A new volumetric program accurately measures ventricular volumes and percent change from baseline across a wide range of volumes.

A prospective comparison between three-dimensional magnetic resonance imaging and ventriculography for target-coordinate determination in frame-based functional stereotactic neurosurgery.

OBJECT: The purpose of this prospective study was to compare stereotactic coordinates obtained with ventriculography with coordinates derived from stereotactic computer-reconstructed three-dimensional magnetic resonance (3D-MR) imaging in functional stereotactic procedures. METHODS: In 15 consecutive patients undergoing functional stereotactic procedures, both preoperative frame-based stereotactic 3D-MR imaging and intraoperative ventriculography were performed. Differences between 3D-MR imaging and ventriculography in X, Y, and Z coordinates of the anterior commissure (AC), posterior commissure (PC), and target area were calculated, as well as the 3D distance between the position of AC, PC, and target within stereotactic space as obtained using both methods. The position of the stereotactic MR imaging fiducial markers measured using 3D-MR imaging compared well with the markers' known position embedded in the software (mean error 0.4 mm, maximal error for an individual slice 1.2 mm). For the individual coordinates, only for Y-PC was a difference found between 3D-MR imaging and ventriculography that significantly exceeded half the size of a pixel, the theoretical limit of precision when using a digitized imaging technique. However, the mean difference was smaller than 1 mm. The mean 3D distance between the 3D-MR imaging- and ventriculography-derived coordinates was 1.09 mm for AC, 1.13 mm for PC, and 1.29 mm for the targets. CONCLUSIONS: With these data it is shown that there is sufficient agreement between ventriculography-derived and 3D-MR imaging-derived stereotactic coordinates to justify the use of 3D-MR imaging target determination in frame-based functional stereotactic neurosurgery.

A stereotaxic template atlas of the macaque brain for digital imaging and quantitative neuroanatomy.

A stereotaxic brain atlas of the longtailed macaque (Macaca fascicularis) is presented in a format suitable for use as a template atlas of the macaque brain. It includes most of the brain segmented to show the boundaries of landmark structures such that every point in the brain can be represented by a unique set of coordinates in three-dimensional space and ascribed unambiguously to one and only one primary structure. More than 400 structures are represented, including 360 volumetric structures, which constitute the substance of the brain, and 50 superficial features. To facilitate use with ventriculography, magnetic resonance imaging, and other noninvasive imaging techniques, the stereotaxic space is referenced to internal landmarks, viz., the anterior commissure and posterior commissure; the center of the anterior commissure at the midline is the origin of the stereotaxic axes. Reference of stereotaxis to this bicommissural space facilitates structural comparison with human brain atlases, which are commonly referenced to the biocommissural line. It also facilitates comparison of brains of different nonhuman primate species by providing a template brain against which to compare size and internal variability. Thirty-three coronal sections at 1-mm intervals from the spinomedullary junction to the rostral extreme of the caudate nucleus show most structures of the hindbrain, midbrain, and subcortical forebrain. Separately, four side views and 16 coronal sections show cortical structures. Structures are represented by outlines of their boundaries and labeled according to NeuroNames, a systematic English nomenclature of human and nonhuman primate neuroanatomy. Abbreviations are based on a protocol designed to facilitate cross-species comparisons. Instructions are provided for: (1) locating sites from the Template Atlas in the conventional stereotaxic space of an experimental animal, (2) locating sites identified by conventional stereotaxis in the Template Atlas, and (3) using the Template Atlas to collate, compare, and display image information (e.g., labeled cells, recording sites, stimulation sites, lesions) from multiple animals.

Stereotactic ventrolateral thalamotomy: is ventriculography necessary?

In the computed tomography/magnetic resonance imaging (CT/MRI) era, the need for ventriculography to perform ventrolateral thalamotomy accurately has been debated. We retrospectively compared CT/MRI-derived coordinates for ventrolateral thalamotomy with the final lesion coordinates that were determined by ventriculography and microelectrode recording in 74 thalamotomies performed from 1984 to 1994. The median three-dimensional distance between the CT/MRI-derived loci and the ventriculography/microelectrode loci was 4.7 mm (range, 1.0-11.7 mm). The techniques correlated least along the Y axis (median, -0.3 mm; range, -8.2 to 8.0 mm). Correlation along the X axis was most consistent (median, 0.5 mm; range, -4.2 to 5.0 mm). Since 1990, the CT/MRI-derived coordinates have been generated by a multimodality correlative imaging technique (MCIT). A comparison of thalamotomies performed with and without the MCIT revealed a significant improvement in the correlation of CT/MRI- and ventriculography/microelectrode-derived coordinates when the MCIT was employed. The greatest improvement was noted along the Y axis where the median absolute difference was reduced from 4.0 to 1.8 mm (P = 0.0001). The result was a statistically significant reduction in the median three-dimensional distance from 5.6 to 3.7 mm (P = 0.0007). The authors conclude that thalamotomies can be safely and effectively performed without ventriculography when the MCIT is employed and supported by neurophysiological monitoring.

Air-ventriculography provokes an anterior displacement of the third ventricle during functional stereotactic procedures.

The width of the third ventricle, the length of the anterior commissure-posterior commissure line (AC-PC line), the spatial position of the midplane of the third ventricle, and the co-ordinates of the AC, the PC, and of 17 brain targets in the thalamus, hypothalamus and pallidum, were assessed on a pre-operative stereotactic computed-tomography (CT) study and compared to measurements on intra-operative air-ventriculography, using a non-invasive relocatable stereotactic frame. There were no significant differences in the length of the AC-PC line, in the position of the midsagittal plane of the third ventricle, or in the vertical or lateral co-ordinates of the AC, the PC and the cerebral targets, between measurements on CT and on air-ventriculography. However, the width of the third ventricle was significantly larger, and the spatial positions of both AC and PC were significantly more anterior on air-ventriculography than on the CT study. This anterior dislocation of the commissures was presumably due to the insufflation of air into the ventricles of patients being in the supine position during surgery.

Image-based functional neurosurgery.

The development of computerized tomography and compatible stereotactic frame and localization devices has improved the ease and accuracy of functional stereotactic neurosurgery. Computerized tomograph-directed functional stereotaxy appears to be a safe and effective means of target development. Magnetic resonance imaging holds the promise of greater anatomical definition and direct sagittal imaging. Significant questions remain, however, concerning the reliability of MRI-based stereotactic neurosurgery, and these must be addressed. Presently, these techniques should be viewed as a means to localize a target region, not the target per se, and, as stated by Apuzzo, "It is not envisioned, however, that the need for intraoperative stimulation will be mitigated by such refinements."

[The problem of infection in measuring brain ventricle pressure]. / Zum Problem der Infektion der Hirnventrikeldruckmessungen.

Catheters for ventriculometry were implanted into the lateral ventricles of 71 neurosurgical patients. Clinical symptoms of meningitis were recorded from 5.6 per cent of them. A positive bacterial culture was obtained in one case. Reference is made to the risk of infection, and prophylactic antibiotic treatment is advocated.

Methodology and clinical experience with computed tomography and a computer-resident stereotactic atlas.

We have developed a computer-resident stereotactic atlas of the human brain that quantitatively defines subcortical structures within anatomical landmarks detected on obliquely reconstructed computed tomography (CT) slices. Horizontal stereotactic atlas sections can be stretched and contracted by polar transformation and labeled by a computer to fit within these CT scan-defined landmarks. The stereotactic coordinates of any substructure on the atlas-labeled CT slice may then be calculated by the computer and expressed in mechanical adjustments on a stereotactic surgical frame located in the operating room. We demonstrate the use of this method in the stereotactic treatment of movement disorders as an augmentation to conventional ventriculography and microelectrode recording.

A new head clamp for stereotactic and intracranial procedures. Technical note.

The authors have devised a clamp to fix the head to the surgical table during stereotactic procedures for placement of depth electrodes. The main advantages of this device derive from the rigid immobilization of the head. The clamp facilitates fixation of the stereotactic frame to the head, percutaneous twist drill trephination of any site of the skull, X-ray centering with a laser beam, mobilization of contrast material during ventriculography or pneumoencephalography, and placement of epidural screws. This head clamp can also be used during craniotomies for fixation of the head and support for brain retractors.

A Concord chair for improved contrast ventriculography.

This paper describes the adaptation of the G.E.C. Concord X-ray couch for controlled contrast ventriculography. The addition of a chair fixture and head-fixing device coupled with a suitable radiographic procedure has made contrast ventriculography a fairly simple and sure technique.

[Subtraction and topography in various cases of ventriculography by means of water-soluble contrast media]. / Subtrakcja i tomografia w niektórych przypadkach wentrykulografii z uzyciem wodnych srodków cieniujacych.

The authors describe the methods of extending the diagnostic possibilities of positive-contrast ventriculography with water-soluble media using the techniques of subtraction and tomography. Side effects occurring during this investigation are mentioned.