Anatomic Neuroimaging Characteristics of Posterior Fossa Type A Ependymoma Subgroups

BACKGROUND AND PURPOSE

Posterior fossa type A (PFA) ependymomas have 2 molecular subgroups (PFA-1 and PFA-2) and 9 subtypes. Gene expression profiling suggests that PFA-1 and PFA-2 tumors have distinct developmental origins at different rostrocaudal levels of the brainstem. We, therefore, tested the hypothesis that PFA-1 and PFA-2 ependymomas have different anatomic MR imaging characteristics at presentation.

MATERIALS AND METHODS

Two neuroradiologists reviewed the preoperative MR imaging examinations of 122 patients with PFA ependymomas and identified several anatomic characteristics, including extension through the fourth ventricular foramina and encasement of major arteries and tumor type (midfloor, roof, or lateral). Deoxyribonucleic acid methylation profiling assigned ependymomas to PFA-1 or PFA-2. Information on PFA subtype from an earlier study was also available for a subset of tumors. Associations between imaging variables and subgroup or subtype were evaluated.

RESULTS

No anatomic imaging variable was significantly associated with the PFA subgroup, but 5 PFA-2c subtype ependymomas in the cohort had a more circumscribed appearance and showed less tendency to extend through the fourth ventricular foramina or encase blood vessels, compared with other PFA subtypes.

CONCLUSIONS

PFA-1 and PFA-2 ependymomas did not have different anatomic MR imaging characteristics, and these results do not support the hypothesis that they have distinct anatomic origins. PFA-2c ependymomas appear to have a more anatomically circumscribed MR imaging appearance than the other PFA subtypes; however, this needs to be confirmed in a larger study.

3T intraoperative MRI for management of pediatric CNS neoplasms

BACKGROUND AND PURPOSE

High-field-strength intraoperative MR imaging has emerged as a powerful adjunct for resection of brain tumors. However, its exact role has not been firmly established. We sought to determine the impact of 3T-intraoperative MRI on the surgical management of childhood CNS tumors.

MATERIALS AND METHODS

We evaluated patient data from a single academic children's hospital during a consecutive 24-month period after installation of a 3T-intraoperative MRI. Tumor location, histology, surgical approach, operating room time, presence and volume of residual tumor, need for tumor and non-tumor-related reoperation, and anesthesia- and MR imaging-related complications were evaluated. Comparison with pre-intraoperative MRI controls was performed.

RESULTS

One hundred ninety-four patients underwent intraoperative MRI-guided surgery. Of these, 168 were 18 years or younger (mean, 8.9 ± 5.0 years; 108 males/60 females). There were 65 posterior fossa tumors. The most common tumors were pilocytic astrocytoma (n = 31, 19%), low-grade glioma (n = 31, 19%), and medulloblastoma (n = 20, 12%). An average of 1.2 scanning sessions was performed per patient (maximum, 3). There were no MR imaging-related safety issues. Additional tumor was resected after scanning in 21% of patients. Among patients with a preoperative goal of gross total resection, 93% achieved this goal. The 30-day reoperation rate was <1% (n = 1), and no patient required additional postoperative MR imaging during the same hospital stay.

CONCLUSIONS

Intraoperative MRI is safe and increases the likelihood of gross total resection, albeit with increased operating room time, and reduces the need for early reoperation or repeat sedation for postoperative scans in children with brain tumors.

M1 medulloblastoma should be considered high risk at any age

2016

Background: Metastatic (M) stage is an important prognostic marker in medulloblastoma. With current therapy including higher-dose craniospinal irradiation and dose intensive chemotherapy, older children with metastatic medulloblastoma have had improved survival. Some investigators have suggested that older children with M1 medulloblastoma be treated as average-risk patients. Additionally, the prognostic value of M1 disease in very young children has not been documented. Methods: We retrospectively reviewed the records of all newly diagnosed medulloblastoma patients treated at St. Jude Children’s Research Hospital from 1984 to 2006. Treatment generally included resection and chemotherapy. Older children received post-operative craniospinal and tumor bed irradiation; radiotherapy for younger children depended on treatment era and physician/family preference. We compared event-free and overall survival for patients with M1 disease to that of patients with M0 and M2/M3 disease for both age groups using the Kaplan-Meier method. Results: 286 patients were included. 56 were <3 years old at diagnosis and 230 were =3 years old. Event-free (EFS) and overall survival (OS) by age and M-stage are reported below. Within the younger group, a significant difference in 5-year EFS was detected among M-stage groups (p<0.002 by Mantel-Haenszel test); 5-year EFS for M0 (n=33), M1 (n=5), and M2/M3 (n=18) patients was 67%, 20%, and 22%, respectively. The difference in 5-year EFS by M-stage was also significant for older patients (p<0.0001); 5-year EFS for 154 M0, 13 M1, and 63 M2/M3 patients was 82%, 59%, and 42%, respectively. Results were similar for OS; differences in OS were significant for older (p<0.0001), but not younger (p=0.21) children. Conclusions: Children <3 years old with M1 medulloblastoma fared poorly in our small series. Survival for older children with M1 disease treated with higher-dose CSI was better than that of M2/M3 patients, but still less than optimal; our findings do not support reduction in therapy for either cohort.

[Table: see text]

No significant financial relationships to disclose.

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.

Heterogeneity of astroglia cultured from adult human temporal lobe

This study characterized the morphological and electrophysiological diversity of astroglia cultured from adult human cerebral temporal lobe, and explored the influence of the cytokine interleukin-1beta on these cells. The cultures contained astroglia positive for glial fibrillary acidic protein which were flat, bipolar or multipolar in shape and variable in size. A subpopulation of the bipolar and multipolar cells was positive for S100 protein. The most striking feature of these cultures was the presence of glia with long (600 micrometer) processes with few branches or only terminal branches. Patch clamp recordings of the non-stellate process bearing cells revealed prominent inward Na(+) and transient and sustained outward K(+) conductances. Distinct differences in the relative proportion of these conductances were evident among cells but did not appear to be correlated with cell morphology. Treatment of cultures with interleukin-1beta for 96 h did not change total protein content, but increased the content of S100beta protein and decreased the content of glial fibrillary acidic protein. The findings indicate that cultures of adult human cerebrum contain subpopulations of morphologically and electrophysiologically pleomorphic glial fibrillary acidic protein positive astroglia, exhibit increased levels of the neurotrophic factor S100beta when exposed to interleukin-1beta, and may serve as a useful model for investigation of glial involvement in neuropathology.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

Outcome analysis of 85 patients undergoing the pi procedure for correction of sagittal synostosis

The authors present a retrospective review of their experience with 85 cases using the pi procedure to correct sagittal synostosis. A male preponderance of four to one was recognized in this group. Sixty-five infants underwent computerized tomography scanning of the head prior to surgery; these scans revealed unexpected intracranial pathology in 5% of cases. Surgical complications included three intraoperative dural lacerations. All children received blood transfusions with no complications. Cosmetic outcomes were excellent in 53%, good in 43%, and poor in 4% of cases. One patient required reoperation. All poor outcomes were in infants who were younger than 8 weeks of age at the time of surgery and who underwent a "reverse pi" procedure. Most of the excellent outcomes occurred in infants who were between 3 and 6 months of age at the time of surgery. Although more extensive than strip craniectomy, the pi procedure can be accomplished with minimal morbidity. In the authors' opinion, the pi procedure provides better immediate and long-term cosmetic results than synostectomy alone.

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.

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.

Lid nystagmus as a sign of intrinsic midbrain disease

A 6-year-old boy with signs and symptoms of ocular myasthenia gravis had lid nystagmus evoked by horizontal gaze. MR imaging demonstrated an intrinsic midbrain lesion, which was diagnosed by biopsy as a low-grade astrocytoma. In the setting of ocular myasthenia gravis, the finding of lid nystagmus may serve as a useful clinical sign of intrinsic midbrain disease.

Nonrandom chromosome breakpoints at Xq26 and 2q33 characterize cemento-ossifying fibromas of the orbit

BACKGROUND

Cytogenetic reports of histologically benign fibroosseous lesions are rare, with only nine previously reported cases. None of these previous studies revealed consistent numerical or structural chromosome aberrations, and to the authors' knowledge, no karyotypic abnormalities in cemento-ossifying fibromas of the orbit have been reported.

METHODS

Short term in situ culture and Giesma-band chromosome methods were used to analyze three cementifying fibromas of the orbit: one from a 13-year-old African American male, one from a 14-year-old Hispanic male, and one from a 17-year-old white male.

RESULTS

Cytogenetic findings in these three cases revealed the presence of identical chromosomal breakpoints occurring in all three tumors at bands Xq26 and 2q33. Two of the tumors showed an identical t(X;2)(q26;q33) reciprocal translocation as the sole abnormality. The third tumor revealed an interstitial insertion of bands 2q24.2q33 into Xq26 as the sole abnormality.

CONCLUSIONS

The authors described new nonrandom breakpoints in fibroosseous lesions of the orbit, which can result from at least two different types of structural chromosomal aberrations. The identification of recurring breakpoints at Xq26 and 2q33 provides a new cytogenetic tumor marker for the identification of this tumor subtype. The sublocalization of breakpoints in this tumor should provide important information for the precise localization and characterization of genes involved in the histiogenesis of these lesions.

Nonrandom chromosome breakpoints at Xq26 and 2q33 characterize cemento-ossifying fibromas of the orbit

BACKGROUND

Cytogenetic reports of histologically benign fibroosseous lesions are rare, with only nine previously reported cases. None of these previous studies revealed consistent numerical or structural chromosome aberrations, and to the authors' knowledge, no karyotypic abnormalities in cemento-ossifying fibromas of the orbit have been reported.

METHODS

Short term in situ culture and Giesma-band chromosome methods were used to analyze three cementifying fibromas of the orbit: one from a 13-year-old African American male, one from a 14-year-old Hispanic male, and one from a 17-year-old white male.

RESULTS

Cytogenetic findings in these three cases revealed the presence of identical chromosomal breakpoints occurring in all three tumors at bands Xq26 and 2q33. Two of the tumors showed an identical t(X;2)(q26;q33) reciprocal translocation as the sole abnormality. The third tumor revealed an interstitial insertion of bands 2q24.2q33 into Xq26 as the sole abnormality.

CONCLUSIONS

The authors described new nonrandom breakpoints in fibroosseous lesions of the orbit, which can result from at least two different types of structural chromosomal aberrations. The identification of recurring breakpoints at Xq26 and 2q33 provides a new cytogenetic tumor marker for the identification of this tumor subtype. The sublocalization of breakpoints in this tumor should provide important information for the precise localization and characterization of genes involved in the histiogenesis of these lesions.

Continuous epidural morphine/butorphanol infusion following selective dorsal rhizotomy in children

The authors prospectively evaluated 15 patients who had undergone selective dorsal rhizotomy who were given a continuous morphine/butorphanol infusion, to determine whether variations in the postoperative pain control and side effects seen using a bolus technique could be reduced. Patients had an epidural catheter placed at the end of the operative procedure through which 50-60 micrograms/kg preservative-free morphine and 15-20 micrograms/kg butorphanol was administered. A continuous epidural infusion of 5 micrograms/kg h morphine and 1.2 micrograms/kg h butorphanol was then initiated. Postoperatively, mean pain scores were excellent. No patient required additional systemic analgesics during the 72-h investigational period. A low incidence of nausea, and no vomiting, pruritus, or respiratory depression was reported by the cohort. All patients maintained oxygen saturations above 95%. This indicates that the use of a continuous epidural infusion provides excellent pain control, decreases the occurrence of untoward side effects, and allows the early initiation of occupational and physical therapy postoperatively.

Ventriculosubgaleal shunt: a treatment option for progressive posthemorrhagic hydrocephalus

Among premature infants born at less than 1500 g, the incidence of intraventricular hemorrhage is greater than 45%. Of these, 40% will develop progressive posthemorrhagic hydrocephalus (PPHH). Optimum treatment remains controversial. Ventriculosubgaleal (VSG) shunts were first proposed as a means of temporarily diverting cerebrospinal fluid (CSF) in a more physiological manner for those infants less than 1500 g in weight who would not tolerate a ventriculoperitoneal (VP) shunt. The VSG shunt could then be converted into a VP shunt when the infant had gained the desired weight. Despite favourable reports, the procedure has not gained universal acceptance and is unknown to many neurosurgeons. The present authors report a series of 15 patients who had VSG shunts inserted with excellent temporary CSF diversion and no complications. Furthermore, 3 out of the 15 patients required no further treatment. We suggest that VSG shunting is a safe and effective means of treating the premature infant with PPHH.

Overexpression of the neurotrophic cytokine S100 beta in human temporal lobe epilepsy

Neuritic sprouting and disturbances of calcium homeostasis are well described in epilepsy. S100 beta is an astrocyte-derived cytokine that promotes neurite growth and induces increases in levels of intracellular calcium in neurons. In sections of neocortex of surgically resected temporal lobe tissue from patients with intractable epilepsy, we found that the number of S100 beta-immunoreactive astrocytes was approximately threefold higher than that found in control patients (p < 0.001). These astrocytes were activated, i.e., enlarged, and had prominent processes. Temporal lobe tissue levels of S100 beta were shown by ELISA to be fivefold higher in 21 epileptics than in 12 controls (p < 0.001). The expression of the astrocyte intermediate filament protein, glial fibrillary acidic protein, was not significantly elevated in epileptics, suggesting a selective up-regulation of S100 beta expression. Our findings, together with established functions of S100 beta, suggest that this neurotrophic cytokine may be involved in the pathophysiology of epilepsy.

A middle-latency auditory-evoked potential in the rat

Previous studies have established the presence of a middle-latency auditory-evoked potential that is characterized by a) sleep-state dependence, b) low following frequency (i.e., rapid habituation to repetitive stimulation), and c) blockade by the cholinergic antagonist, scopolamine. A vertex-recorded evoked potential having these characteristics was described in humans at a 50-80 ms latency (termed the P1 or.P50 potential) and in the cat at a 20-25 ms latency (termed wave A). These studies were undertaken to determine if a click stimulus-evoked potential having the same characteristics was present in the intact rat. Vertex and auditory cortex recordings in intact rats studied in a sound-attenuating chamber and exposed to free-field click stimuli showed a) the presence of a vertex recorded potential at a 11-15 ms latency, termed P13, and of an auditory cortex recorded potential at a 7-11 ms latency, termed Pa; b) the P13 was present during waking and paradoxical sleep but absent in slow-wave sleep, while Pa was present in all sleep-wake states; c) the P13 habituated markedly at stimulation rates above 1 Hz while Pa did not; and d) the P13 was blocked by low doses of scopolamine while Pa was not. These studies demonstrate the presence of a P1-like potential in the rat at a 13 +/- 2 ms latency.

Results of temporal lobectomy for the treatment of partial complex epilepsy

Epilepsy is the third most common cause of neurologic disability. The disease carries a 15 prevalence and a 3.5% lifetime risk. Seventy percent of patients can achieve good seizure control with medication. The remaining 30%, some 360,000 people across the United States, have intractable epilepsy and would benefit from evaluation at an epilepsy specialty center where surgical intervention is an option. The following report reviews a series of 50 patients referred to the Arkansas Comprehensive Epilepsy Program for treatment of intractable complex partial epilepsy. In this series, we evaluate results of temporal lobectomy, commenting upon factors in the patients' histories which may influence their outcomes.

Increased neuronal beta-amyloid precursor protein expression in human temporal lobe epilepsy: association with interleukin-1 alpha immunoreactivity

Levels of immunoreactive beta-amyloid precursor protein and interleukin-1 alpha were found to be elevated in surgically resected human temporal lobe tissue from patients with intractable epilepsy compared with postmortem tissue from neurologically unaffected patients (controls). In tissue from epileptics, the levels of the 135-kDa beta-amyloid precursor protein isoform were elevated to fourfold (p < 0.05) those of controls and those of the 130-kDa isoform to threefold (p < 0.05), whereas those of the 120-kDa isoform (p > 0.05) were not different from control values. beta-Amyloid precursor protein-immunoreactive neurons were 16 times more numerous, and their cytoplasm and proximal processes were more intensely immunoreactive in tissue sections from epileptics than controls (133 +/- 12 vs. 8 +/- 3/mm2; p < 0.001). However, neither beta-amyloid precursor protein-immunoreactive dystrophic neurites nor beta-amyloid deposits were found in this tissue. Interleukin-1 alpha-immunoreactive cells (microglia) were three times more numerous in epileptics than in controls (80 +/- 8 vs. 25 +/- 5/mm2; p < 0.001), and these cells were often found adjacent to beta-amyloid precursor protein-immunoreactive neuronal cell bodies. Our findings, together with functions established in vitro for interleukin-1, suggest that increased expression of this protein contributes to the increased levels of beta-amyloid precursor protein in epileptics, thus indicating a potential role for both of these proteins in the neuronal dysfunctions, e.g., hyperexcitability, characteristic of epilepsy.

Chromosome aberrations in four ependymomas

Cytogenetic analysis of short-term cultures from three untreated and one recurrent ependymoma revealed clonal aberrations in three of the four tumors. A posterior fossa ependymoma from a 3-year-old male patient showed trisomy 11 as the sole clonal chromosome aberration. A recurrent spinal ependymoma from a 35-year-old male showed hypertriploid clones with abnormalities involving chromosomes 1p11,7q21, and 10p13. A 62-year-old male patient with a cerebellar ependymoma showed a hypodiploid stem-cell line with clonal structural aberrations of both the long and short arms of chromosome 1, an interstitial deletion of 2q, trisomy 7, and monosomy for chromosomes 11, 13, and 16. A 3-year-old female patient with posterior fossa ependymoma showed a normal 46,XX karyotype. Chromosome 1 aberrations appear to be the most consistent finding in this small series of tumors, with the net loss or rearrangement of chromosome 1 pter-->p22 material from two of the four tumors. These findings, in addition to a previously published case [1], suggest a possible role for genes on the short arm of chromosome 1 in the cytogenetic evaluation of ependymomas.

Use of full-thickness calvarial bone grafts for cervical spinal fusions in pediatric patients

The use of full-thickness calvarial bone grafts for cervical spinal fusions appears to be effective and safe in pediatric patients requiring stabilization of the cervical spine. The grafts create solid fusions, better immediate internal stabilization, and the procedure is associated with less morbidity than those using autologous grafts of rib or iliac crest.

Replacement laminoplasty in selective dorsal rhizotomy: possible protection against the development of musculoskeletal pain

The authors present a retrospective review of 35 patients who underwent selective dorsal rhizotomy between 1990 and 1992. The first 15 patients underwent laminectomy from L1 to the sacrum without replacement of the posterior elements. The subsequent 20 patients had the laminae replaced during wound closure. No patient in either group developed spinal instability or symptomatic deformity. However, 4 patients in the first group (mean follow-up period 35 months) developed significant low-back pain of musculoskeletal origin following minor accidents (mean time to injury 12 months). No patients in the group in whom the laminae were replaced (mean follow-up period 24 months) developed back pain. This review suggests that although the lumbar laminae are not essential for the structural integrity of the spine, their removal may predispose to musculoskeletal injury and associated pain. The authors propose a mechanism for these findings and recommend replacement of the posterior elements when possible.

The P1: insights into attention and arousal

The authors provide evidence that four mesencephalic nuclei, two of which are cholinergic and two of which are catecholaminergic, serve as oscillators capable of modulating a number of interrelated rhythmic functions. These include sleep-wake cycles, locomotion, blood pressure, respiratory rate, heart rate, mastication, micturition, and saccadic eye movements. The P1 auditory evoked potential is generated by ascending cholinergic projections from one of these nuclei, the pedunculopontine nucleus, and thus serves as a clinical tool to monitor the integrity of this system.

Brachial plexopathy in infants after traumatic delivery: evaluation with MR imaging

PURPOSE

To determine the value of magnetic resonance (MR) imaging in diagnosing traumatic pseudomeningocele.

MATERIAL AND METHODS

Five newborn infants with brachial plexopathy secondary to traumatic delivery underwent MR imaging of the spine and serial neurologic examinations, and the findings were compared.

RESULTS

Cervical MR images showed focal collections of cerebrospinal fluid lateral to the spinal cord and extending into the neural foramina. These were believed to represent pseudomeningoceles in four infants, all of whom have persistent major neurologic deficits. The infant with normal cervical MR images has had nearly complete spontaneous recovery.

CONCLUSION

Spinal MR images can show pseudomeningoceles, which have been associated with partial or complete nerve root avulsion in infants with birth-related brachial plexopathy.

Ring chromosome 12 resulting from nonrandom telomeric associations with the short arm of chromosome 15 in a cerebellar astrocytoma

Ring chromosome 12 was found in an untreated cerebellar astrocytoma apparently resulting from nonrandom telomeric associations involving the short arm of chromosome 15, and both the long and short arms of chromosome 12. The clonal nonrandom telomeric associations of 15p to both ends of the chromosome 12 were transitory, but appear to be the precursor lesion in the evolution to ring chromosome 12 in this tumor. A multistep process in the formation of a ring chromosome resulting from nonrandom telomeric associations to both telomeres is illustrated.

Cerebral revascularization with an artificial graft: long-term follow-up and discussion of the role of graft pretreatment with modified host endothelial cells

Controversy remains regarding the effectiveness of EC/IC bypass for the prevention of stroke and the authors believe that some studies suggest that a subcategory of patients disabled by transient flow-related symptoms may benefit from surgery. The authors present a 7 1/2 year follow-up analysis of a patient who had undergone an EC/IC bypass from the proximal extracranial carotid to the middle cerebral artery using a 4 mm Gore-Tex prosthesis. Following his death from pulmonary sepsis, the graft was retrieved. Pathological and electron microscopic findings are reviewed.

Meningiomas in children: MR and histopathologic findings

PURPOSE

To present the MR and histopathologic findings in five children with meningiomas.

METHODS

Five children aged 3 months to 16 years with pathologically proved meningiomas underwent preoperative contrast enhanced MR. Tissue in four patients was sent for chromosomal analysis in addition to routine histopathologic studies.

RESULTS

All five tumors were extra-axial, two supratentorial and three in the posterior fossa. MR showed variable signal intensity on precontrast T1-weighted images. All of the tumors were hyperintense on proton density- and T2-weighted images and showed intense contrast enhancement. Histopathologic analysis showed two meningotheliomatous, one transitional, one chordoid, and one hemangiopericytic variant of meningioma. Chromosomal analysis showed deletions involving chromosome 22 in two of four tumors studied.

CONCLUSION

Meningiomas in children have a higher incidence of posterior fossa location and different histologic types than seen in adults. MR showed the tumors in our patients to be extra-axial, hyperintense on proton density- and T2-weighted images with intense enhancement on postcontrast T1-weighted images. Chromosomal aberrations were noted in two patients.

Diagnosis and management of the tethered cord syndrome

Tethering of the spinal cord can occur from a thickened filum terminale, scarring due to myelomeningocele repair, lipomas or diastematomyelia. The typical presentation is a lumbar cutaneous defect, enuresis, unexplained back or leg pain, foot deformities, leg length discrepancies or scoliosis. Spinal ultrasound in neonates and MRI in older children offers ready diagnosis. With laser and microneurosurgical techniques, repair of these defects is safe and effective. The authors recommend that any infant having a mid-line lumbar cutaneous abnormality, such as a hemangioma, lipoma, hair patch or dimple, be evaluated to rule out tethering of the spinal cord.

Telomeric associations evolving to ring chromosomes in a recurrent pleomorphic xanthoastrocytoma

Telomeric associations observed in a recurrent untreated pleomorphic xanthoastrocytoma were apparently the primary cytogenetic events that evolved by fusion and breakage events, resulting in subclones with ring chromosomes. The telomeric fusions between chromosomes 15pter and 20qter, and between an extra copy of the long arm of chromosome 1 and chromosome 22qter, evolved in a stepwise fashion to ring chromosomes 20 and 22. The findings in this tumor demonstrate that telomeric association is one mechanism that can initiate chromosome instability by generating subclones with unstable chromosome intermediates and result in ring chromosomes and subsequent chromosome loss.

The subarachnoid spaces in craniosynostosis

A review of 85 patients with various forms of craniosynostosis showed predictable patterns of dilatation of the subarachnoid spaces in regions of compensatory skull growth. The characteristic pattern in sagittal synostosis (43 patients) included dilatation of the frontal and occipital subarachnoid spaces associated with the elongation of the anteroposterior dimension of the skull and widening of the interhemispheric fissure. In 11 patients with unilateral coronal synostosis, dilatations of the subarachnoid spaces over the contralateral frontal lobe, the sylvian regions, and the ipsilateral temporal lobe tip were consistent with the skull changes of contralateral frontal bossing, increased bitemporal dimension, and elevation of the sphenoid wing, respectively. Four patients with bilateral coronal synostosis also had enlarged subarachnoid spaces high over the convexities of the brain consistent with the towering configuration of the skull. Four patients with true lambdoid synostosis had dilatation of the subarachnoid space only over the ipsilateral frontal lobe associated with compensatory bossing of the frontal bone. Ten of 14 patients with lambdoid deformities had bilateral enlargement of the subarachnoid spaces suggesting brain atrophy and an underlying motor delay accounting for the position-induced skull changes. The findings suggest that focal hydrodynamic mechanisms are involved in the compensatory skull changes seen in craniosynostosis.

Meningioma and sagittal craniosynostosis in an infant: case report

The occurrence of a frontal base meningioma in a 3-month-old infant seen for the treatment of sagittal craniosynostosis is reported. The association of the two lesions is of interest both because it is unique and may lend support to theories of the cause of some forms of craniosynostosis.

Molecular cytogenetic analysis of a medulloblastoma with isochromosome 17 and double minutes

Cytogenetic analysis of a medulloblastoma revealed two abnormal cell lines of 48,XY, +8, +8, -14, +der(14)t(1;14)(q11;p11),i(17q) and 51,XY, +5, +6, +8, +8, -14 + 20, +der (14)t(1;14)(q11;p11),i(17q), + dmin. The finding of double minute chromosomes in some medulloblastomas has been associated with amplification of the c-myc or N-myc oncogenes. We were unable to detect gene amplification with these probes by Southern blot analysis.

Silastic duraplasty in pediatric patients

The role of adhesions in the retethering of the neural elements after surgical treatment of spinal dysraphism has produced refinements in the technique of the closure of the neural tube. Silastic, because of its relative inert property, has been used for duraplasty, but a few reports of late complications of hemorrhage or fibrotic capsule formation have caused concern over its use. We report 33 patients with the following diagnoses--eight spinal lipomyelomeningoceles, three myelomeningoceles, six symptomatic Chiari II malformations, seven tethered cords, six spinal cord tumors, two diastematomyelia, and one cerebellar astrocytoma--in whom Silastic dural grafts were used to prevent the adherence of neural structures to the overlying tissues. Our surgical technique is presented here. The patients have been observed for up to 6 years. Only one became infected, was treated with antibiotics without graft removal, and has remained without sequelae for over 3 years. One had an incidental pseudomeningocele that was noted on follow-up magnetic resonance imaging scan that was not clinically apparent. There have been no hemorrhages, leakage of cerebrospinal fluid, nor other complications from using nonreinforced Silastic sheeting. In one patient, Dacron-reinforced Silastic was used and, upon reexploration, a marked fibroblastic response was noted. A review of the literature suggests that fibrotic complications are related to this Dacron-reinforced Silastic. The hemorrhagic complications that were reported occurred in instances where Silastic grafts were large and no technical modifications were made preventively. We conclude that the use of nonreinforced Silastic dural grafts, with appropriate technical modifications in surgical technique, is safe and may prevent retethering of neural tissues in a variety of neurosurgical lesions.

Cytogenetic findings in a pleomorphic xanthoastrocytoma

We report a pleomorphic xanthoastrocytoma with an abnormal clonal cell line of 48,XY, +3, +5, -20, -22, +der(7)t(7;?)(p22;?), +der(20)t(15;20)(q11;q13).

Selective posterior rhizotomy for relief of spasticity

Results of sensory rhizotomy for the treatment of spasticity have been dramatically improved by newer microsurgical techniques employing intraoperative electrophysiological monitoring. This is now the treatment of choice for spasticity related to cerebral palsy. The goal of surgery is to achieve a permanent reduction in spasticity thereby improving ambulation and activities of daily living.