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Biomedical subjects

James M Drake

Publications and source records attributed to James M Drake.

At least 19 recordsLinked to original sources
PubMed2006

Basal ganglia germinoma in children with associated ipsilateral cerebral and brain stem hemiatrophy.

BACKGROUND: Germinoma is the most common and least-malignant intracranial germ cell tumor, usually found in the midline. Germinoma that arises in the basal ganglia, called ectopic germinoma, is a rare and well-documented entity representing 5% to 10% of all intracranial germinomas. The association of cerebral and/or brain stem atrophy with basal ganglia germinoma on CT and MRI is found in 33% of the cases. OBJECTIVE: To review the literature and describe the CT and MRI findings of basal ganglia germinoma in children, known as ectopic germinoma, with associated ipsilateral cerebral and brain stem hemiatrophy. MATERIALS AND METHODS: Three brain CT and six brain MRI studies performed in four children at two institutions were retrospectively reviewed. All patients were male (case 1, 14 years; case 2, 13 years; case 3, 9 years; case 4, 13 years), with pathologically proved germinoma arising in the basal ganglia, and associated ipsilateral cerebral and/or brain stem hemiatrophy on the first imaging study. It is important to note that three of these children presented with cognitive decline, psychosis and slowly progressive hemiparesis as their indication for imaging. RESULTS: Imaging results on initial scans were varied. In all patients, the initial study showed ipsilateral cerebral and/or brain stem hemiatrophy, representing Wallerian degeneration. All patients who underwent CT imaging presented with a hyperdense or calcified lesion in the basal ganglia on unenhanced scans. Only one of these lesions had a mass effect on the surrounding structures. In one of these patients a large, complex, heterogeneous mass appeared 15 months later. Initial MR showed focal or diffusely increased T2 signal in two cases and heterogeneous signal in the other two. CONCLUSION: The association of a focal lesion in the basal ganglia of children with progressive hemiparesis, neuropsychiatric symptoms and ipsilateral cerebral and/or brain stem hemiatrophy should prompt the diagnosis of ectopic germinoma, avoiding delay in the diagnosis and further irreversible clinical deterioration, in a malignancy with an otherwise favorable prognosis. In these patients, hemiatrophy preceding or accompanying the imaging depiction of a basal ganglia mass lesion is thought to be caused by a paraneoplastic process.

Adolescent↗
PubMed2006

Recanalization of obstructed cerebrospinal fluid ventricular catheters using ultrasonic cavitation.

OBJECTIVE: Fifty percent of implanted cerebrospinal fluid (CSF) shunts fail within 2 years, primarily because of obstruction of the proximal catheter. Percutaneous techniques to reduce the morbidity of shunt revision are being developed. The authors describe the development of a device that uses ultrasonic cavitation to unblock ventricular catheters. METHODS: In collaboration with Cybersonics, Inc. (Erie, PA), we designed, built, and tested a system that produces low-frequency ultrasound (20-28 kHz). Extensional ultrasonic waves are transmitted along a tapered wire (final diameter, approximately 0.8 mm) to the tip, where cavitation is produced in a highly localized region. An in vitro model of sheep choroid plexus occluding typical ventricular catheters was developed. The device was safety tested in vivo in rat and pig brains by introducing the device into shunt catheters inserted during simulated shunt surgery. A clinical safety trial using the device to attempt to remove blocked and adherent ventricular catheters has commenced. RESULTS: In the sheep choroid plexus model, at least 90% of the occluded holes were unblocked in a few minutes, restoring normal flow. There was no adverse effect of the device within shunt catheters inserted into live animal brains. Four patients have undergone treatment with the device at open CSF shunt surgery without adverse effect, and the device seems effective at unblocking and freeing the occluded catheters. CONCLUSION: Ultrasonic cavitation produced at the end of a fine wire that is introduced percutaneously into a CSF shunt promises to be a useful technique for minimally invasive proximal ventricular CSF shunt catheter revision.

Animals↗
PubMed2006

Occult tethered cord syndrome: not an indication for surgery.

OBJECT: The author describes the paucity of information known about occult tethered cord syndrome and summarizes the argument for using a nonsurgical approach in these cases. METHODS: A review of what we do and do not know about this syndrome is provided. Surgical procedures to divide the terminal filum in patients with symptoms of tethered spinal cord without the imaging correlates are said to result in clinical improvement, yet there is little physiological evidence to support the surgical release of the filum in the absence of other anatomical lesions. Validated diagnostic and outcome measures are also lacking, which makes the interpretation of reported results exceedingly difficult. Finally, reports used to support surgical intervention are limited by small size, the absence of control groups, and observer bias. CONCLUSIONS: Without conclusive clinical evidence, the arguments supporting surgery for occult tethered cord syndrome must be viewed cautiously.

Child↗
PubMed2006

Shunt insertion in the summer: is it safe?

OBJECT: The potential for increased complications related to the arrival of new residents in July each year has not previously been demonstrated in the neurosurgical literature. The authors investigated this phenomenon in children undergoing cerebrospinal fluid shunt surgery. METHODS: Data were obtained from a multicenter hydrocephalus clinical trials database and from hospital admission records in English-speaking Canada. Data pertaining to patients treated in July and August were compared with those pertaining to patients treated during the remainder of the year. The incidence of shunt failure, shunt infection, neurological deficits, wound infection, technical errors, and death were compared using a chi-square test for categorical outcomes, means for continuous outcomes, and survival analysis for time-dependent outcomes. In the hydrocephalus clinical trials database, 138 of 737 patients were treated in July and August. The median duration of shunt lifespan (hereafter referred to as "shunt survival") was 1.7 years for patients treated during the summer months and 2.4 years for those treated throughout the rest of the year (p = 0.10); for shunt infection the figures were 13.8 and 8.8% (p = 0.08) of the total number of cases, and for wound dehiscence they were 2.9 and 0.7% (p = 0.05), respectively. When all shunt procedures were included, an examination of shunt survival and infection incidence rates recorded in the Canadian Hospital Discharge Database seemed to imply a significant advantage to having surgery between September and June (log-rank statistic = 7.10, p = 0.008). CONCLUSIONS: The data suggest a "July effect" on some outcomes related to shunt surgery, but the effect was small. Nonetheless, the potential morbidity of shunt failure, infection, and the cost of treatment indicate that continued vigilance and appropriate supervision of new staff by attending surgeons is warranted.

Canada↗
PubMed2006

Management of shunt infections: a multicenter pilot study.

OBJECT: Approximately 10% of cerebrospinal fluid (CSF) shunt operations are associated with infection and require removal or externalization of the shunt, in-hospital treatment with antibiotic agents, and insertion of a new shunt. In a previous survey, the authors identified substantial variation in the duration of antibiotic therapy as well as the duration of hospital stay. The present multicenter pilot study was undertaken to evaluate current strategies in the treatment of shunt infection. METHODS: Patients were enrolled in the study if they had a successful treatment of a CSF shunt infection proved by culture of a CSF specimen. Details of their care and the incidence of culture-proved reinfection were recorded. Seventy patients from 10 centers were followed up for 1 year after their CSF shunt infection. The initial management of the infection was shunt externalization in 17 patients, shunt removal and external ventricular drain insertion in 50, and antibiotic treatment alone in three. Reinfection occurred in 18 patients (26%). Twelve of the 18 reinfections were caused by the same organism and six were due to new organisms. The treatment time varied from 4 to 47 days, with a mean of 17.4 days for those who later experienced a reinfection compared with 16.2 days for those who did not. The most common organism (Staphylococcus epidermidis, 34 patients) was associated with a reinfection rate of 29% and a mean treatment time of 12.8 days for those who suffered reinfection and 12.5 days for those who did not. CONCLUSIONS: Reinfection after treatment of a CSF shunt infection is alarmingly common. According to the data available, the incidence of reinfection does not appear to be related to the duration of antibiotic therapy.

Adolescent↗
PubMed2005

Peripersonal spatial attention in children with spina bifida: associations between horizontal and vertical line bisection and congenital malformations of the corpus callosum, midbrain, and posterior cortex.

Horizontal and vertical line bisection was studied in 129 children and adolescents between 8 and 19 years of age, one group (n=32) of typically developing controls and one group (n=97) with spina bifida (SBM), a neurodevelopmental disorder associated with dysmorphology of the corpus callosum, posterior cortex, and midbrain. For each participant, structural brain MRIs were analyzed qualitatively to identify beaking of the midbrain tectum and corpus callosum agenesis and hypoplasia and quantitatively by segmentation and volumetric analyses of regional cortical white and gray matter. Each group showed the line length effect, whereby greater estimation errors are made with longer lines. The group with SBM differed from controls in terms of both accuracy and variability of line bisection. Children with SBM showed pseudoneglect, attending more than controls to left hemispace. The extent of rightward bisection bias was unrelated to right posterior brain volumes, although an intact corpus callosum during development moderated and normalized the exaggerated leftward line bisection bias. More children with SBM than controls attended to inferior hemispace. A normal midbrain and greater posterior cortex volume during development moderated and normalized the downward bias. Children with SBM showed more intra-subject variability than controls. Line bisection in children with SBM reflects three deficits: an exaggerated attentional bias to left hemispace, an abnormal attentional bias to inferior hemispace; and a larger zone of subjective uncertainty in bisection judgments.

Adolescent↗
PubMed2005

Space-based inhibition of return in children with spina bifida.

Inhibition of return (IOR) refers to an increase in time to react to a target in a previously attended location. Children with spina bifida meningomyelocele (SBM) and hydrocephalus have congenital dysmorphology of the midbrain, a brain region associated with the control of covert orienting in general and with IOR in particular. The authors studied exogenously cued covert orienting in 8- to 19-year-old children and adolescents (84 with SBM and 37 age-matched, typically developing controls). The exogenous cue was a luminance change in a peripheral box that was 50% valid for the upcoming target location. Compared with controls, children with SBM showed attenuated IOR in the vertical plane, a deficit that was associated with midbrain dysmorphology in the form of tectal beaking but not with posterior brain volume loss. The data add to the emerging evidence for SBM deficits in attentional orienting to salient information.

Adolescent↗
PubMed2005

Spinal lesion level in spina bifida: a source of neural and cognitive heterogeneity.

OBJECT: The aim of this study was to evaluate whether the level of a spinal lesion is associated with variations in anomalous brain development and neurobehavioral outcomes in children suffering from the meningomyelocele form of spina bifida and hydrocephalus (SBM-H). METHODS: Two hundred sixty-eight children with SBM-H were divided into upper (T-12 and above; 82 patients) and lower (L-1 and below; 186 patients) lesion-level groups. Magnetic resonance images were qualitatively coded by radiologists and quantitatively segmented for cerebrum and cerebellum volumes. Psychometric assessments of handedness, intelligence, academic skills, and adaptive behavior were compared between lesion-level groups and also used to determine the number of children who met research-based criteria for mental retardation, attention deficit hyperactivity disorder, and learning disabilities. The magnetic resonance images obtained in children with upper-level spinal lesions demonstrated more qualitative abnormalities in the midbrain and tectum, pons, and splenium, although not in the cerebellum, compared with images obtained in children with lower-level spinal lesions. Upper-level lesions were also associated with reductions in cerebrum and cerebellum volumes, lower scores on measures of intelligence, academic skills, and adaptive behavior, and with a higher frequency of individuals meeting the criteria for mental retardation. Hispanic children (who were also more economically disadvantaged) were more likely to have upper-level lesions and poorer neurobehavioral outcomes, but lesion-level effects were generally independent of ethnicity. CONCLUSIONS: A higher level of spinal lesion in SBM-H is a marker for more severe anomalous brain development, which is in turn associated with poorer neurobehavioral outcomes in a wide variety of domains that determine levels of independent functioning for these children at home and school.

Adolescent↗
PubMed2005

Children and television tipovers: a significant and preventable cause of long-term neurological deficits.

OBJECT: Television tipover has recently been recognized as a significant cause of injury in children, and head injury accounts for most of the associated deaths. The authors reviewed their experience with children who sustained head injury from falling televisions. METHODS: Children admitted with the diagnosis of head injury related to falling televisions since 1992 were identified from the authors' trauma database, and a retrospective review of the medical records was performed. Eighteen patients were identified: 13 boys and five girls whose ages ranged from 12 months to 10 years (mean 44 months). The admission Glasgow Coma Scale (GCS) score was 15 in 10 patients. Only three patients had a GCS score of 8 or less (one patient had a score of 4). Neurological examinations were normal in 10 patients; three had cranial nerve deficits and three had otorrhea, otorrhagia, or hemotympanum. Radiological abnormalities included 16 skull fractures, three epidural hematomas, three small subdural hematomas, one intracranial hemorrhage, and three venous obstructions of the transverse-sigmoid sinus. The mean hospital stay was 8.9 days (range 2-39 days). Follow up at 0.2 to 68 months (mean 13.4 months) revealed severe neurological deficits in one patient and cranial nerve deficits of cranial nerves six, seven, or eight in six patients. CONCLUSIONS: Falling televisions result in significant head injuries in children, with substantial short- and long-term sequelae. This injury is easily preventable through simple measures taken by both the manufacturers and caregivers.

Accidents↗
PubMed2005

Near-miss injection of an anesthetic agent into a cerebrospinal fluid external ventricular drain: special report.

OBJECTIVE AND IMPORTANCE: Human error has been increasingly recognized as a cause of patient morbidity and mortality. One method of error prevention is the reporting of a near-miss event. We report that intravenous anesthetic agents were nearly injected into the external ventricular drainage (EVD) of a patient during an emergency shunt procedure. CLINICAL PRESENTATION: A 3-year-old male patient with multiple cerebrospinal fluid shunts and shunt infection had an external ventricular drain catheter tunneled to exit just inferior to the left clavicle during a previous procedure. The exit site was covered by an occlusive dressing. This particular system, the Codman external drainage system II collection bag and tubing set (Codman & Shurtleff, Inc., Raynham, MA), contains two access ports (a three-way stoppered port and an angled rubber stoppered injection port). At induction of anesthesia, the EVD system was mistaken for a central venous line and was nearly injected with propofol and rocuronium. Fortunately, the error was quickly recognized and the patient came to no harm. INTERVENTION AND TECHNIQUE: A modified EVD system has recently been released that does not include the three-way port, and features an embedded bright green stripe in the tubing to distinguish it from intravenous tubing. CONCLUSION: We recommend using caution when tunneling EVDs to sites that might be confused with central venous access sites. EVD system tubing should be designed so it can be easily distinguished from intravenous tubing, and it should be clearly labeled as an EVD line.

Anesthetics↗
PubMed2004

Covert orienting to exogenous and endogenous cues in children with spina bifida.

Children with spina bifida meningomyelocele and hydrocephalus (SBM) have congenital dysmorphology of the midbrain and thinning of the posterior cortex, brain regions associated with the control of covert orienting. We studied cued covert orienting in 92 children with SBM, and 40 age-matched typically developing controls. Cues were of three types: exogenous (luminance change in a peripheral box either valid or invalid for upcoming target location), endogenous arrow (a central arrow either valid or invalid for upcoming target location), or endogenous word (a central word either valid or invalid for upcoming target location). Compared to controls, children with SBM showed slowed covert orienting to both exogenous and endogenous cues and a higher cost of attentional disengagement (e.g., a greater cue-validity effect) for exogenous although not for endogenous cues. Covert orienting deficits were associated with midbrain dysmorphology in the form of beaking of the tectum, and with right posterior brain volume loss.

Adolescent↗
PubMed2004

Neurobiology of perceptual and motor timing in children with spina bifida in relation to cerebellar volume.

The cerebellum is important for perceptual and motor timing in the mature brain, but the timing function of the cerebellum in the immature brain is less well understood. We investigated timing in children with spina bifida meningomyelocele (SB), a neural tube defect that involves cerebellar dysgenesis, and in age-matched controls. Specifically, we studied perceptual timing (judgements of 400 ms duration) and motor timing (isochronous motor tapping); measured cerebellar volumes; and related perceptual and motor timing to each other and to cerebellar volume measurements. Children with SB had impairments in the perception of duration (around 400 ms) but not frequency (around 3000 Hz), showing that their perceptual timing deficit was not a generalized auditory impairment. Children with SB had motor timing deficits on unpaced but not paced isochronous tapping, and their unpaced timing performance was associated with clock variance rather than with motor implementation. Perceptual and motor timing were correlated, suggesting that children with SB have impairments in a central timing mechanism. Children with SB, especially those with upper spinal cord lesions, had significant cerebellar volume reductions in grey and white matter, as well as different regional patterns of grey matter, white matter and CSF. Duration perception was correlated with cerebellar volumes, and the number of valid tapping trials was correlated with cerebellar volumes in the SB group, which data demonstrate structure-function relations between timing and cerebellar volumes.

Acoustic Stimulation↗
PubMed2004

Results of endoscopic third ventriculostomy.

ETV is emerging as the treatment of choice for aqueductal stenosis caused by anatomic, inflammatory, and selected neoplastic etiologies. The technique has also proven useful in the pathologic diagnosis and treatment of these conditions. Long-term results of this procedure and comparison to standard shunting procedures are necessary to define indications for patients with pathologic findings in the intermediate response groups. Development of new studies for pre-operative assessment of CSF absorptive capacity and quantitative postoperative measures of ventriculostomy function would be invaluable additions to our ability to assess candidates for this procedure and their eventual outcome. Further study and technical refinements will, no doubt, lead to many more potential uses for these procedures in the treatment of hydrocephalus and its associated etiologies. The challenge for neuro-surgeons will be to define the operative indications and outcomes, while refining techniques for safely performing these useful procedures.

Humans↗
PubMed2004

Destruction of choroid plexus cells in vitro: a new concept for the treatment of hydrocephalus?

OBJECTIVE: The current treatment of hydrocephalus using ventriculoperitoneal shunts and third ventriculostomies remains problematic. We revisited the concept of destruction of the choroid plexus for the treatment of hydrocephalus by using an immunotoxin-based technique to specifically destroy this tissue. This approach was based on the observation that, as an epithelial tissue, choroid plexus expresses a number of specific cell-surface proteins that represent excellent potential targets for the creation of a choroid plexus-specific immunotoxin. METHODS: In this study, we characterized sheep and human choroid plexus cells (including atypical and carcinoma cell lines) using fluorescence microscopy in combination with histochemical staining of rat brain and confirmed the presence of a number of epithelium-specific proteins in choroid plexus cells. Immunotoxins were then manufactured by linking these antibodies to ricin A chain and ricin A-B chain. These immunotoxins were delivered to choroid plexus-derived cells in culture, and the results were compared with results of exposure to a nonspecific immunotoxin. RESULTS: Complete cell death of choroid plexus cells was seen after only a 1-hour exposure to the specific immunotoxin, as opposed to the minimal cell death seen with a nonspecific immunotoxin after several hours of exposure. CONCLUSION: These results suggest that immunotoxin-mediated ablation of choroid plexus may be a viable method of treating hydrocephalus and choroid plexus-derived tumors.

Animals↗