Controversies in the surgical management of Chiari I malformations: what is the surgical procedure of choice? To open dura or not to open dura?
Explore the source record for details and available documents.
Arnold-Chiari Malformation↗
Biomedical subjects
Richard G Ellenbogen
Publications and source records attributed to Richard G Ellenbogen.
BMP-2 mediates retinoid-induced apoptosis in medulloblastoma cells through a paracrine effect.
The mechanisms of retinoid activity in tumors remain largely unknown. Here we establish that retinoids cause extensive apoptosis of medulloblastoma cells. In a xenograft model, retinoids largely abrogated tumor growth. Using receptor-specific retinoid agonists, we defined a subset of mRNAs that were induced by all active retinoids in retinoid-sensitive cell lines. We also identified bone morphogenetic protein-2 (BMP-2) as a candidate mediator of retinoid activity. BMP-2 protein induced medulloblastoma cell apoptosis, whereas the BMP-2 antagonist noggin blocked both retinoid and BMP-2-induced apoptosis. BMP-2 also induced p38 mitogen-activated protein kinase (MAPK), which is necessary for BMP-2- and retinoid-induced apoptosis. Retinoid-resistant medulloblastoma cells underwent apoptosis when treated with BMP-2 or when cultured with retinoid-sensitive medulloblastoma cells. Retinoid-induced expression of BMP-2 is thus necessary and sufficient for apoptosis of retinoid-responsive cells, and expression of BMP-2 by retinoid-sensitive cells is sufficient to induce apoptosis in surrounding retinoid-resistant cells.
Animals↗
Ultrasound screening of the lambdoid suture in the child with posterior plagiocephaly.
BACKGROUND: The child with posterior plagiocephaly may have positional molding or unilateral lambdoid synostosis. Molding responds to conservative treatment, lambdoid synostosis requires surgical reconstruction. CT is diagnostic, but uses ionizing radiation, may need sedation, and the incidence of lambdoid fusion is only 2-3%. OBJECTIVE: The purpose of this prospective study was to evaluate ultrasound as a screening test of lambdoid sutural patency using CT as the reference standard. MATERIALS AND METHODS: In total, 41 children having head CT examinations were enrolled over 6 months. Of those, 29 were referred for abnormal head shape and suspected synostosis, of whom two had lambdoid fusion; 12 were referred for indications not related to head shape and found to have a normal study. Ultrasound scanning and interpretation of the lambdoid sutures was performed blinded to the CT reference standard. The lambdoid suture was read as patent or fused if a hypoechoic gap could or could not be seen between the hyperechoic calvarial bones, respectively. RESULTS: The mean sensitivity and specificity of ultrasound in distinguishing a patent from fused lambdoid suture by three blinded pediatric radiologists was 100% and 89%, respectively. CONCLUSIONS: Sonography of the lambdoid sutures shows excellent preliminary promise as a screening test of lambdoid sutural patency.
Cranial Sutures↗
Tumors and malformations of the caudal spinal axis.
The early development of the neural tube has been well studied in animals and humans. After axial determinants have been accomplished the processes of primary and secondary neurulation take place. Successful completion results in a spinal cord that has arisen from primary neurulation and a lower sacro-coccygeal portion from secondary neurulation. The latter region is the site of numerous skin-covered clinical lesions, which include tumors and malformations. A listing of selected features in 764 cases of skin-covered sacrococcygeal lesions is presented. The manner in which these lesions arise and the potential for genetic factors being responsible is discussed.
Diagnosis, Differential↗
Direct repair of the pars interarticularis for spondylolysis and spondylolisthesis.
Spondylolysis and spondylolisthesis can be associated with significant low back pain, especially in physically active adolescents. Non-operative management is usually successful in improving symptoms, but surgical intervention is occasionally required for those that fail reduction of activity and bracing. In a subpopulation of these patients, direct repair of the pars interarticularis defect can be an effective modality of treatment. The advantage of direct pars repair over intertransverse fusion with or without segmental instrumentation is the preservation of the anatomic integrity and motion of the affected segment. We describe our experience in 5 patients (aged 15-18 years) managed by direct pars interarticularis repair after failing multimodality non-operative treatment. The length of stay averaged 3.2 days (range 3-4 days). All 5 patients were able to return to full activity with either no (60%) or minor (40%) symptoms. No immediate or delayed complications were noted. Patients were followed a minimum of 30 months (range 30-78 months). All 5 patients demonstrated evidence of bony fusion by radiographic criteria. This demonstrates that direct pars repair is a safe and effective modality to treat select groups of patients with spondylolysis and low-grade spondylolisthesis.
Adolescent↗
A large planum sphenoidale meningioma with sinonasal extension in a child. Case report and review of the literature.
Anterior cranial base meningiomas are rare tumors in children. Due to the extensive involvement of orbit, paranasal sinuses, midface, and anterior skull base, a multidisciplinary approach is warranted. We present a case of a child with a large planum sphenoidale meningioma extending into subfrontal region, ethmoid and maxillary sinuses inferiorly, and orbits laterally. The patient, a 4-year-old girl, presented with long-standing nasal stuffiness and swelling of the midface. An extended frontobasal approach through a bifrontal craniotomy was used to resect the intracranial portion of this mass. The tumor had eroded through nasal septum, medial orbital walls, and left maxilla, structures which were not readily accessible from a cranial approach alone. A modified Weber-Ferguson incision was used for a transfacial approach to resect the residual mass below the skull base. The advantages of combining the bifrontal craniotomy with a transfacial split provided the added exposure to maximize the extent of resection.
Child, Preschool↗
Pediatric spine and spinal cord injury after inflicted trauma.
Pediatric spine and spinal cord injury are rare sequelae of intentional trauma. They may easily be overlooked, however, and probably represent an underreported phenomenon. Recent autopsy data analyzed in conjunction with prior case series indicate that injury to the upper cervical spine and brainstem may significantly contribute to the major morbidity, mortality, and neuropathology in shaken infants. The findings in the previous case report illustrate several important points regarding spine and spinal cord injury after intentional trauma. First, the very young are susceptible to severe, higher cervical injury of both spine and spinal cord. Second, spine and spinal cord injury were initially overlooked because of masked neurologic findings with the concomitant head injury and multiple other systemic injuries. Finally, the child's outcome with significant cognitive delay because of global brain injury in conjunction with the focal high cervical cord injury may support the hypothesis that hypoxic damage could have occurred secondary to brainstem and high cervical cord injury. At the authors' institution, a detailed history and vigilant physical examination are stressed. When the mechanism of injury reported in the history is incongruous with the physical or initial radiographic findings and intentional trauma is suspected, a full skeletal survey, ophthalmologic evaluation, and social evaluation is undertaken. MRI and CT scanning are individualized according to the clinical assessment.
Child↗
The diagonal ventricular dimension: a method for predicting shunt malfunction on the basis of changes in ventricular size.
OBJECTIVE: Serial computed tomographic and magnetic resonance imaging studies are critical in the evaluation of patients who present with symptoms and signs of recurrent hydrocephalus or possible ventricular shunt malfunction. Subtle changes in ventricular volume or complex variations in ventricular anatomy often make subjective assessment of changes in ventricular size difficult, and no previously described method relates these changes to intracranial pressure or shunt system function. The purpose of this study was to develop an objective, reproducible, simple linear method of detecting changes in ventricular size that provides an accurate reflection of shunt function on the basis of serial imaging studies. METHODS: We developed a simple, linear estimate of ventricular volume--the diagonal ventricular dimension--to objectively assess changes in ventricular size on serial computed tomographic scans and magnetic resonance imaging scans. Serial imaging studies for 14 patients ages 1.6 to 71 years who underwent evaluation for shunt malfunction were used in this study. The sensitivity and specificity of this method in predicting shunt malfunction was compared with other well-established linear estimates of ventricular size as well as with a radiologist's interpretation of the same studies. The "gold standard" for measuring the status of ventricular shunt system function in this study was the measurement of intracranial pressure via shunt tap or surgical exploration results. RESULTS: The sensitivity (100%) and specificity (100%) of the diagonal ventricular dimension in detecting changes in ventricular size consistent with shunt malfunction was superior to that of any other linear estimate and to a radiologist's interpretation of the same films. CONCLUSION: The diagonal ventricular dimension provides an objective, simple linear method of assessing changes in ventricular size that correlates well with shunt system function in the context of a collaborative examination.
Adult↗
Focal motor seizures with secondary generalization arising in the cerebellum. Case report and review of the literature.
The issue of whether seizures can arise in the cerebellum remains controversial. The authors present the first known case of focal subcortical epilepsy with secondary generalization thought to arise from a dysplastic lesion within the cerebellum. A newborn infant presented with daily episodes of left eye blinking, stereotyped extremity movements, postural arching, and intermittent altered consciousness lasting less than 1 minute. These episodes began on his 1st day of life and progressively increased in frequency to more than 100 events per day. Antiepileptic medications had no effect, and interictal and ictal scalp electroencephalography (EEG) recordings demonstrated bilateral electrical abnormalities. Magnetic resonance imaging revealed a mass in the left cerebellar hemisphere, and ictal and interictal single-photon emission computerized tomography revealed a focal perfusion abnormality in the region of the cerebellar mass. The patient subsequently underwent intraoperative EEG monitoring with cortical scalp electrodes and cerebellar depth electrodes. Intraoperative EEG recordings revealed focal seizure discharges that arose in the region of the cerebellar mass and influenced electrographic activity in both cerebral hemispheres. Resection of this mass and the left cerebellar hemisphere led to complete resolution of the patient's seizures and normalization of the scalp EEG readings. Neuropathological findings in this mass were consistent with ganglioglioma. A review of the literature on the cerebellar origins of epilepsy is included.
Cerebellar Cortex↗
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.
Cerebral Ventricles↗
Rapid computed tomography technique to measure ventricular volumes in the child with suspected ventriculoperitoneal shunt failure II. Clinical application.
OBJECTIVES: Assessment of ventricular volume change is critical in the child with suspected shunt failure. Minimal increases may represent high pressures in the child with reduced ventricular compliance but are difficult to detect subjectively. Objective techniques described limit anatomic sampling and are time intensive. The purpose of this study was to develop a rapid technique to measure ventricular volumes in children with suspected shunt failure. METHODS: Ventricular volumes were calculated in 12 children with baseline and emergent computed tomography scans performed for suspected shunt failure. Volumes and percent interval changes were correlated with clinical course. Two observers performed the volume analysis blinded to the clinical information; 1 observer performed the analysis twice. Time to perform the analysis was recorded for 5 studies. RESULTS: The intraobserver and interobserver correlation coefficients were 0.99 and 0.96/0.97, respectively. The mean time to perform the analysis was 2 minutes 42 seconds. Median percent change in patients with and without shunt obstruction was +50% (range: +24%-+367%) and +2% (range: -22%-+36%), respectively. Among patients subjectively read as having stable ventricular sizes, volume changes of -11% to +32% were calculated. CONCLUSIONS: The technique has excellent intra- and interobserver correlation and is rapidly performed. The range of percent volume changes between patients with and without shunt malfunction overlaps. Subjective assessment of ventricular changes is significantly less sensitive than the volume calculation technique. The technique may be most useful in patients with decreased ventricular compliance in whom small interval changes may represent large pressure increases.
Adolescent↗
Vertex epidural hematoma.
Explore the source record for details and available documents.
Abducens Nerve Injury↗