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Biomedical subjects

F A Boop

Publications and source records attributed to F A Boop.

At least 19 recordsLinked to original sources
PubMed2006

Diffusion tensor imaging of tract involvement in children with pontine tumors.

BACKGROUND AND PURPOSE: Conventional MR imaging permits subcategorization of brain stem tumors by location and focality; however, assessment of white matter tract involvement by tumor is limited. Diffusion tensor imaging (DTI) is a promising method for visualizing white matter tract tumor involvement supratentorially. We investigated the ability of DTI to visualize and quantify white matter tract involvement in pontine tumors. METHODS AND MATERIALS: DTI data (echo-planar, 1.5T) were retrospectively analyzed in 7 patients with pontine tumors (6 diffuse, 1 focal), 4 patient controls, and 5 normal volunteers. Fractional anisotropy (FA) and apparent diffusion coefficient (ADC) were calculated from the diffusion tensor in 6 regions of interest: bilateral corticospinal tracts, transverse pontine fibers, and medial lemnisci. Relationships between FA and ADC values and results of the neurologic examinations were evaluated. RESULTS: The corticospinal tracts and transverse pontine fibers were affected more often than the medial lemnisci. The DTI parameters (FA and ADC) were significantly altered in all tracts of patients with pontine tumors (P < .05), compared with those values in the control groups. A marginally significant (P = .057) association was seen between the severity of cranial nerve deficit and decreased FA. CONCLUSION: DTI provided superior visualization and quantification of tumor involvement in motor, sensory, and transverse pontine tracts, compared with information provided by conventional MR imaging. Thus, DTI may be a sensitive measure of tract invasion. Further prospective studies are warranted to assess the ability of DTI to delineate tumor focality and improve risk stratification in children with pontine tumors.

Adolescent↗
PubMed1999

Porcine small intestinal submucosa as a dural substitute.

BACKGROUND: The continuing search for the ideal dural substitute is currently directed toward collagen preparations. Xenogeneic porcine small intestinal submucosa (SIS), a naturally occurring extracellular matrix rich in collagen, has been successfully used as a soft tissue graft in several body organ systems, including preliminary studies as a dural substitute in the rat. METHODS: Eight dogs underwent temporoparietal craniotomy and dural resection with replacement by SIS. Five dogs had contralateral procedures without SIS grafting. Three dogs had contralateral SIS grafts placed 2 months after the initial procedure. Histologic assessment was obtained at 7, 30, 60, 90, and 120 days. Cerebrospinal fluid (CSF) cytological examination and routine serum chemistry preceded sacrifice. RESULTS: Histologic evaluation showed initial graft infiltration by mononuclear round cells, spindle-shaped cells within an eosinophilic staining extracellular matrix, and neovascularity. Complete resorption of the graft was evident by 60 days. This pattern is consistent with the previously described incorporation and remodeling of the SIS graft at other sites. CSF cytology and routine serum chemistry at the time of sacrifice were normal. Response to repeat grafting was identical to that of initial exposure. There was no clinical or histologic evidence of sensitization or graft rejection. No evidence of adverse effect on the underlying cerebral cortex was observed. CONCLUSIONS: Porcine small intestinal submucosa demonstrates a favorable biologic response as a dural substitute in the canine model. It is a promising biomaterial for dural replacement.

Animals↗
PubMed1999

Spitting automatism in complex partial seizures: a nondominant temporal localizing sign?

PURPOSE: Spitting as an ictal automatism has been rarely reported. We aimed to establish its potential lateralizing and localizing significance. METHODS: Review of patients undergoing surgery for intractable epilepsy at two comprehensive epilepsy centers. RESULTS: Five patients were found who had spitting as a stereotyped automatism of their complex partial seizures. All had evidence of right temporal ictal onset and underwent resective surgery. Two had tumors; one, a cavernous angioma; one, hippocampal gliosis, and one, hippocampal sclerosis. We found no instances of ictal spitting in patients with left hemisphere onset. CONCLUSIONS: Spitting as an automatism in complex partial seizures, although uncommon, may be a localizing sign to the nondominant temporal lobe.

Adult↗
PubMed1999

Involution of enhancing intrinsic tectal tumors after endoscopic third ventriculostomy. Report of two cases.

For benign intrinsic tectal tumors causing triventricular obstructive hydrocephalus, cerebrospinal fluid diversion followed by neuroimaging is a widely accepted treatment plan. In this report, the authors describe two children with focal enhancing tectal lesions that caused acute, symptomatic hydrocephalus. One child had neurofibromatosis Type 1 (NF1). In both children the hydrocephalus was effectively treated by endoscopic third ventriculostomy. Following this procedure, serial imaging studies revealed not only that the ventriculomegaly had resolved, but also that the enhancing tectal tumors had regressed and disappeared over time. The time to complete involution of these tumors was 18 months for the child with NF1 and 12 months for the other child. To the authors' knowledge, this is the first report of the involution of enhancing tectal tumors after endoscopic third ventriculostomy. The possible mechanisms for this unexpected result are discussed.

Acute Disease↗
PubMed1999

Inside-outside technique for posterior occipitocervical spine instrumentation and stabilization: preliminary results.

OBJECT: The authors present a series of 16 patients who underwent inside-outside occipital and posterior cervical spine stabilization. METHODS: In this technique, the screw was placed from the inside of the occiput to the outside. An articular (lateral) mass plate was contoured to the shape of the occipital bone and the cervical spine and affixed to the occiput with a flat-headed screw or stud placed through a burr hole in the calvaria with the flat head of the screw in the epidural space and the threads facing outward. The bone plate was then secured with a nut to the occipital screw and the cervical plate was attached to the spine with a bone screw that coursed through the plate and into the articular pillar. Our series included six children and 10 adults. In five patients, previous fusion had failed; in two patients spinal instability was secondary to Down's syndrome; two patients' instability was related to developmental anomalies; and in five patients spinal instability was due to the presence of tumor. One patient with rheumatoid arthritis had undergone a transoral procedure. Two patients had suffered traumatic fracture. Three patients died of causes unrelated to the procedure, one patient died of metastatic cancer, and one patient died in a long term care facility of cardiopulmonary complications. One patient with renal failure suffered a hemorrhage from an arteriovenous fistula after being treated with dialysis. In one child, a nut backed off after 3 months. The nut was reseated, and a maturing arthrodesis was present. CONCLUSIONS: The authors conclude that the inside-outside occipitocervical fixation is an effective technique for stabilizing the cervical spine.

Adolescent↗
PubMed1998

Cognition and behavior after temporal lobectomy in pediatric patients with intractable epilepsy.

The increased use of surgical intervention for intractable epilepsy during childhood has resulted in a critical need for information concerning possible cognitive and behavioral changes in pediatric patients after surgery. In this pilot study, comprehensive neuropsychologic evaluations were completed on nine children who had a temporal lobectomy for intractable epilepsy before 16 years of age. Performances before and after surgery were compared using cognitive and behavioral measures. Repeated measures analysis of variance did not indicate differences in performance on the basis of laterality of surgery, although the number of left (n = 5) vs right (n = 4) temporal resections was small. Paired comparison t tests, which included all patients, did not suggest marked changes in cognitive functioning after surgery, although decreases in delayed verbal memory were evident. Positive effects on quality of life during the first year after surgical intervention were suggested by reduced internalizing symptoms and increased social interaction. Replication of this study is recommended with a larger number of patients and multicenter collaboration.

Adolescent↗
PubMed1998

Neurologic injuries associated with all-terrain vehicles and recommendations for protective measures for the pediatric population.

OBJECTIVE: To present data and case studies illustrating the danger, especially in the pediatric population, of all-terrain vehicle (ATV) use, and to provide recommendations for pediatricians on how to educate parents concerning ATVs. DESIGN: Retrospective review of 33 patients with neurologic injuries sustained in ATV accidents presenting to one institution over a 40-month period. SETTING: Emergency department and neurosurgery service at Arkansas Children's Hospital and two other hospitals that make up the University of Arkansas for Medical Sciences. PATIENTS: All patients (n = 33) who presented between January 1993 and April 1996 at the emergency departments with neurologic injuries sustained in accidents involving either a three- or four-wheel ATV requiring hospitalization. INTERVENTIONS: Depending on the nature of the injury, various treatments, as described herein. MAIN OUTCOME MEASURES: Demographic measures, the mechanisms of injury, the types of injuries; the current data available regarding the number of injuries nationwide; and the precautionary measures parents should be advised to take. RESULTS: Ages ranged from four to 68 years (mean, 18; median, 14), 21 of the patients were < 16 years old. The predominant age range was 12 to 15 years; most common mechanisms of injury were being thrown to the ground, striking a tree, and flipping backward. Most injuries were cranial (21) or spinal (11). Nationwide, the proportionate number of injuries are decreasing, but the consequences remain severe. Using a helmet and restricting the use of these vehicles will reduce the number and magnitude of injuries. CONCLUSIONS: Although perceived as recreational toys, ATVs can be extremely unsafe, especially for children and adolescents; pediatricians should educate parents and patients on the dangers of riding these vehicles.

Accidents↗
PubMed1997

Decreased habituation of midlatency auditory evoked responses in Parkinson's disease.

The P1 midlatency auditory evoked potential was studied in patients with Parkinson's disease and compared to that in age-matched controls. Habituation of the potential was determined by using a two-click stimulus paradigm in which the stimuli were presented at 250-, 500-, and 1,000-ms interstimulus intervals. Results showed that habituation of the P1 potential had a statistically significant decrease at the 250-ms and 500-ms interstimulus intervals in patients with Parkinson's disease compared to normal controls. The degree of decreased habituation was found to increase with severity of the disease such that stage 5 patients showed greater decreases in habituation compared to stage 4, as did stage 4 compared to stage 3. These findings may be explained by the presence of a dysregulation of sensory processing, possibly by elements of the reticular activating system, including the pedunculopontine nucleus, in Parkinson's disease.

Aged↗
PubMed1997

Combat veterans with posttraumatic stress disorder exhibit decreased habituation of the P1 midlatency auditory evoked potential.

The current study used a paired stimulus paradigm to investigate the P1 midlatency auditory evoked potential in Vietnam combat veterans with posttraumatic stress disorder (PTSD) and three comparison groups: alcohol dependents, combat-exposed normals, and combat-unexposed normals. Compared to each comparison group, PTSD subjects exhibited significantly diminished habituation of the P1 potential. P1 potential habituation within the PTSD group, correlated significantly with intensity of PTSD reexperiencing symptoms, such as trauma-related nightmares and flashbacks. These findings are discussed as consistent with a sensory gating defect at the brainstem level in PTSD, and are further discussed in the context of other psychophysiological measures in PTSD and of P1 potential findings in psychiatric disorders other than PTSD.

Analysis of Variance↗
PubMed1997

Fourth ventricular ependymoma in a child with Duane retraction syndrome.

A child with unilateral Duane retraction syndrome developed signs and symptoms of increased intracranial pressure at 3 1/2 years of age. Neuroimaging disclosed a fourth ventricular ependymoma compressing but not invading the floor of the fourth ventricle. The coexistence of Duane syndrome and fourth ventricular ependymoma in a young child raises the possibility that both conditions could have resulted from a mutational event or focus of cellular disorganization (i.e. field defect) localized to the dorsal pons.

Cerebral Ventricle Neoplasms↗
PubMed1997

The Chiari II malformation: a surgical series.

Thirty patients between the ages of 7 months and 24 years were treated surgically for symptomatic Chiari II malformation at the Arkansas Children's Hospital. All patients underwent at least bony decompression of the malformation. Assessments of the patients' conditions were made at 6 weeks and 1 year after surgery, and complications of surgery were noted. For a majority of the patients, the presenting symptoms were resolved following treatment (74% at 6 weeks and 80% at 1 year). Partial resolution occurred in several of the patients (17% at 6 weeks and 14% at 1 year). A small number remained the same at 6 weeks (6%) and at 1 year (3%), while 1 patient was worse after surgery. Ten of the patients with complete resolution in the short term required repeat surgery an average of 49 months after their original operation, after which they again attained complete resolution of their symptoms. Scales for clinical, radiographic and operative grading of the patients' conditions as mild, moderate or severe were devised, and these were employed to characterize the condition of each patient. Patients in each grading category had good results, with rates of complete symptomatic resolution ranging from 67 to 100%. Severity in each category was found to be well correlated with eventual recurrence of symptoms and need for reoperation.

Adolescent↗
PubMed1996

Proliferation of astroglia from the adult human cerebrum is inhibited by ethanol in vitro.

Chronic alcoholism is associated with atrophy of the adult brain, while fetal exposure to ethanol can cause microencephaly. Since astroglial pathology is a common feature of ethanol exposure in both humans and animal models, the direct influence of ethanol on proliferation of human astroglia from the gray and white matter of adult temporal lobe was determined and compared. Astroglial cultures were exposed to constant concentrations of ethanol at realistic social and clinical levels (0.1, 0.2 or 0.5%; w/v) for 1 to 5 days. Proliferation was quantified by bromodeoxyuridine labeling and enumeration of replicating cells. Ethanol exposure significantly inhibited proliferation of both gray and white matter astroglia in a dose and duration dependent manner. Gray matter was slightly more sensitive than white matter to inhibition by low to moderate concentrations of ethanol; in contrast, white matter was more sensitive to high ethanol concentrations. Maximum inhibition was 20% in gray matter and 25% in white matter. Human astroglial proliferation was directly inhibited in the absence of neurons, microglia, neuronal degeneration or systemic factors that have confounded in vivo studies. Restricted astroglial proliferation may underlie aspects of the astroglial pathology associated with ethanol exposure.

Adult↗
PubMed1996

Complications of endoscopic neurosurgery.

Neuroendoscopy is rapidly becoming an essential part of the neurosurgeon's repertoire. Currently, very few studies have identified the complications of this new technique, yet many have warned of the steep learning curve associated with its practice. We have reviewed the last 173 neuroendoscopic procedures performed by one surgeon and identified two distinct groups of complications: those that have clinically significant sequelae and those that cause concern intraoperatively but no overt clinical problems. The 173 procedures were performed on 152 patients. Of these patients, 11 suffered significant complications (7%). Twenty-two of the procedures were complicated by intraoperative problems (13%). The incidence of insignificant complications appeared to decrease with experience, whereas that of the significant ones did not. These complications occurred in association with a wide variety of operations over a 2-year period. We conclude that neuroendoscopy is a relatively safe technique with an overall 7% complication rate and a steep learning curve, and that, with a few simple guidelines, it can be employed by all neurosurgeons for the betterment of their patients.

Adolescent↗
PubMed1996

Synostectomy versus complex cranioplasty for the treatment of sagittal synostosis.

Although pediatric neurosurgeons traditionally have been trained to perform a sagittal synostectomy for the treatment of sagittal synostosis, numerous articles advocating modifications of this procedure or more complex cranial vault reconstructions point our the inadequacies of strip craniectomy in providing optimal short- and long-term cosmesis. This review addresses the major arguments for and against performing complex cranioplasties for sagittal synostosis, as well as issues regarding timing of surgery, mortality and morbidity, increased need for blood transfusion, and increased expense. The authors support the contention that for the majority of infants with sagittal synostosis, complex calvarial vault reconstruction provides a better outcome with little increase in operative risk.

Cephalometry↗
PubMed1996

Histology after dural grafting with small intestinal submucosa.

BACKGROUND: The search for the ideal dural substitute continues, inasmuch as available materials have significant limitations. Xenogeneic porcine small intestinal submucosa (SIS) has been successfully used as a soft tissue graft in several body organ systems, and it was logical to evaluate its use as a dural replacement. METHODS: Twenty rats underwent bihemispheric craniectomy with dural resection. SIS onlay grafting on one side was performed. Histologic assessment was obtained at 7 and 28 days after dural grafting and included descriptive evaluation and quantitative scoring of graft-site thickness, vascularity, and cellular density. The total scores for the respective groups were compared using the Student's t test, significance being accepted for a p value < 0.05. RESULTS: Histologic evaluation showed graft infiltration by spindle-shaped mononuclear cells, deposition of connective tissue, and neovascularity. This pattern is consistent with the previously described incorporation and remodeling of the SIS graft at other sites. A significant difference between the histologic scores of the SIS graft site and control site was found at 7 days (3.4 +/- 0.8 versus 0.1 +/- 0.1) and at 28 days (4.6 +/- 1.1 versus 2.2 +/- 0.5). No evidence of adverse effect on the underlying cortex was observed. CONCLUSIONS: The results of this preliminary study utilizing porcine SIS as a dural substitute are promising and therefore justify further chronic studies.

Animals↗