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Paul A. Grabb

Two cases of intracranial capillary hemangiomas (ICHs) occurring in children are presented to highlight the surgical challenges encountered with these extremely rare lesions. The author describes their clinical presentation, preoperative imaging features, intraoperative findings, and operative management. The pertinent literature is reviewed. Recommendations for preoperative planning and intraoperative management are made based on the author’s experience and the literature for when ICH is considered in the differential diagnosis and encountered intraoperatively.

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Paul Grabb

Introduction

Creation of a pediatric neurosurgical service in the community has challenges unique from establishing such a service in an academic setting. I outline the challenges in creating a pediatric neurosurgical service within a large city-owned hospital. Critical equipment system-related and man-power issues were identified.

Methods

The NACHRI designated children's hospital (Memorial Hospital for Children) serves southern Colorado. Coverage was not provided by the community neurosurgeons. Therefore, children requiring neurosurgical management traveled to Denver or elsewhere. A pediatric neurosurgeon was hired to establish a clinical service in 2004.

Results

Equipment such as endoscopy, frameless stereotaxy, ICP monitors, and shunt components were obtained easily. Familiarizing the OR/ICU staff with the equipment, however, required months as this technology was rarely utilized by the other surgeons. System-related concerns were many and mostly educational involving the ER, PICU, NICU, and floor. Identifying anesthesiologists with pediatric expertise and desire was critical. Unexpected system-related benefits compared to a university-based Children's Hospital were lack of resistance for imaging studies requiring sedation or invasive studies (angiography), outstanding intraoperative support for spinal instrumentation cases, very rapid transport to OR of trauma patients, and speed of anesthesia. Man-power issues of no cross-coverage remain problematic primarily because of insurance premium increases to provide pediatric coverage. Any increased burden by nonresidents is offset by the support of other specialties (emergency room physicians, intensivists, and trauma surgeons). Physician extenders require a large amount of education and oversight before reducing clinical burden.

Conclusion

Creating a pediatric neurosurgical service within a community hospital requires financial support from the hospital, a system capable of and willing to care for children with complex problems and other specialties, and physician extenders competent to assist with the service. The medicolegal/insurance landscape hinders more complete coverage within our system. A tremendous educational effort is required to establish and maintain a safe and functional service.

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Paul A. Grabb and Mark R. Gilbert

✓ The authors investigated the effects of glioma cells and pharmacological agents on the permeability of an in vitro blood-brain barrier (BBB) to determine the following: 1) whether malignant glia increase endothelial cell permeability; 2) how glucocorticoids affect endothelial cell permeability in the presence and absence of malignant glia; and 3) whether inhibiting phospholipase A2, the enzyme that releases arachidonic acid from membrane phospholipids, would reduce any malignant glioma—induced increase in endothelial cell permeability.

Primary cultures of rat brain capillary endothelium were grown on porous membranes; below the membrane, C6, 9L rat glioma, T98G human glioblastoma, or no cells (control) were cocultured. Dexamethasone (0.1 µM), bromophenacyl bromide (1.0 µM), a phospholipase A2 inhibitor, or nothing was added to culture media 72 hours prior to assaying the rat brain capillary endothelium permeability. Permeability was measured as the flux of radiolabeled sucrose across the rat brain capillary endothelium monolayer and then calculated as an effective permeability coefficient (Pe). When neither dexamethasone nor bromophenacyl bromide was present, C6 cells reduced the Pe significantly (p < 0.05), whereas 9L and T98G cells increased Pe significantly (p < 0.05) relative to rat brain capillary endothelium only (control). Dexamethasone reduced Pe significantly for all cell preparations (p < 0.05). The 9L and T98G cell preparations coincubated with dexamethasone had the lowest Pe of all cell preparations. The Pe was not affected in any cell preparation by coincubation with bromophenacyl bromide (p > 0.45).

These in vitro BBB experiments showed that: 1) malignant glia, such as 9L and T98G cells, increase Pe whereas C6 cells probably provide an astrocytic influence by reducing Pe; 2) dexamethasone provided significant BBB “tightening” effects both in the presence and absence of glioma cells; 3) the in vivo BBB is actively made more permeable by malignant glia and not simply because of a lack of astrocytic induction; 4) tumor or endothelial phospholipase A2 activity is probably not responsible for glioma-induced increased in BBB permeability; and 5) this model is useful for testing potential agents for BBB protection and for studying the pathophysiology of tumor-induced BBB disruption.

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Dachling Pang and Paul A. Grabb

✓ Long-term patency of the ventricular catheter of a cerebrospinal fluid shunt depends on the positioning of the hole-bearing segment of the catheter. Placement of this segment near the choroid plexus or injured ependyma increases the probability of obstruction. Proper positioning for a coronal shunt in turn depends on the ventricular catheter length and target coordinates. The authors describe a method of calculating the catheter length based on bone landmarks on skull radiographs, and a technique for accurate ventricular catheter placement using free-hand passage guided by simple stereotactic coordinates based on visible and palpable surface anatomy. The insertion trajectory is aligned with the coronal obliquity of the lateral ventricle so that, even with slit ventricles, the entire hole-bearing segment of the catheter can be reliably situated within the anterior horn. The predetermined catheter length also fixes the tip at the foramen of Monro, away from the choroid plexus and injured ependyma.

Of 160 children undergoing ventriculoperitoneal shunt insertion using this technique, only three required catheter revision during a mean follow-up period of 39 months. Radiographic grading of the ventricular catheter position in 112 children showed a satisfactory placement rate of 93.2%; all three children with occlusion showed poor catheter positioning. Thus, this method results in accurate ventricular catheter placement with a 1.9% obstruction rate, which compares favorably to the 16% to 18% incidence of proximal obstruction reported in the literature. This technique is applicable to patients of all ages but is particularly suitable for children because of the greater variability in head size.

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Paul A. Grabb, A. Leland Albright, and Basil J. Zitelli

✓ The authors present an unusual case in which increased intracranial pressure developed because of multiple-suture craniosynostosis and megaloencephaly in a child with a previously undiagnosed lysosomal storage disease, α-d-mannosidase deficiency. This 3-year-old boy presented with a history of frequent naps, headaches, florid papilledema, enlarged head (> 95th percentile), elevated opening pressure by lumbar puncture, a “beaten copper” appearance on skull radiographs, and no hydrocephalus. Multiple synostectomies were performed. Postoperatively, the child's headaches and papilledema resolved and his level of physical activity increased dramatically. The authors discuss the paradoxical presentation of prematurely fused sutures and macrocrania in light of this lysosomal storage disease and its subsequent management.

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Bermans J. Iskandar, Gary L. Hedlund, Paul A. Grabb, and W. Jerry Oakes

Object. To provide more information about this rare condition, the authors describe five cases of syringohydromyelia without hindbrain herniation. Preoperative magnetic resonance imaging with and without gadolinium—diethylenetriamine pentaacetic acid revealed no evidence of spinal cord tumor, arachnoiditis, or spinal dysraphism.

Methods. Craniocervical decompression was performed in all patients, after which there was resolution of the symptoms in the four symptomatic patients, and all five showed marked reduction in the size of the syrinx.

Conclusions. The authors hypothesize the rare occurrence of syringohydromyelia resulting from a Chiari-like pathophysiological condition but lacking a hindbrain hernia. Patients with this condition may benefit from craniocervical decompression.

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Bermans J. Iskandar, Gary L. Hedlund, Paul A. Grabb, and W. Jerry Oakes

Object

To provide more information about this rare condition, the authors describe five cases of syringohydromyelia without hindbrain herniation. Preoperative magnetic resonance imaging with and without gadolinium-diethylenetriamine pentaacetic acid revealed no evidence of spinal cord tumor, arachnoiditis, or spinal dysraphism.

Methods

Craniocervical decompression was performed in all patients, after which there was resolution of the symptoms in the four symptomatic patients, and all five showed marked reduction in the size of the syrinx.

Conclusions

The authors hypothesize the rare occurrence of syringohydromyelia resulting from a Chiari-like pathophysiological condition but lacking a hindbrain hernia. Patients with this condition may benefit from craniocervical decompression.

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Paige Lundy, Christian Kaufman, David Garcia, Michael D. Partington, and Paul A. Grabb

OBJECTIVE

The authors conducted a retrospective analysis of a consecutive series of children with intracranial subdural empyemas (SEs) and epidural abscesses (EAs) to highlight the important clinical difference between these two entities. They describe the delays and pitfalls in achieving accurate diagnoses and make treatment recommendations based on clinical and imaging findings.

METHODS

They reviewed their experience with children who had presented with intracranial SE and/or EA in the period from January 2013 to May 2018. They recorded presenting complaint, date of presentation, age, neurological examination findings, time from presentation to diagnosis, any errors in initial image interpretation, timing from diagnosis to surgical intervention, type of surgical intervention, neurological outcome, and microbiology data. They aimed to assess possible causes of any delay in diagnosis or surgical intervention.

RESULTS

Sixteen children with SE and/or EA had undergone evaluation by the authors’ neurosurgical service since 2013. Children with SE (n = 14) presented with unmistakable evidence of CNS involvement with only one exception. Children with EA alone (n = 2) had no evidence of CNS dysfunction. All children older than 1 year of age had sinusitis.

The time from initial presentation to a physician to diagnosis ranged from 0 to 21 days with a mean and median of 4.5 and 6 days, respectively. The time from diagnosis to neurosurgical intervention ranged from 0 to 14 days with a mean and median of 3 and 1 day, respectively. Delay in treatment was due to misinterpretation of images, a failure to perform timely imaging, progression on imaging as an indication for surgical intervention, or the managing clinician’s preference. Among the 14 cases with SE, initial imaging studies in 6 were not interpreted as showing SE. Four SE collections were dictated as epidural even on MRI. The only fatality was associated with no surgical intervention. Endoscopic sinus surgery was not associated with reducing the need for repeat craniotomy.

CONCLUSIONS

Regardless of the initial imaging interpretation, any child presenting with focal neurological deficit or seizures and sinusitis should be assumed to have an SE or meningitis, and a careful review of high-resolution imaging, ideally MRI with contrast, should be performed. If an extraaxial collection is identified, surgical drainage should be performed expeditiously. Neurosurgical involvement and evaluation are imperative to achieve timely diagnoses and to guide management in these critically ill children.

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R. Shane Tubbs, John C. Wellons III, Jeffrey P. Blount, Paul A. Grabb, and W. Jerry Oakes

✓The authors report on three pediatric patients with ventriculoperitoneal (VP) shunts who presented with chronic right shoulder pain. Imaging revealed that the distal peritoneal catheter was positioned between the right hemidiaphragm and liver. Following surgical repositioning of the distal tubing, all patients experienced resolution of their shoulder pain, which has not recurred. Although seemingly rare, referred shoulder pain from a VP shunt should be added to the list of complications seen with this method of cerebrospinal fluid diversion. The clinician who cares for patients with VP shunts may wish to evaluate cases of shoulder pain without obvious neural or musculoskeletal cause by performing imaging of the distal shunt tubing.

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R. Shane Tubbs, George Salter, Paul A. Grabb, and W. Jerry Oakes

Object. The authors conducted a study to examine the detailed anatomy of the denticulate ligaments and to assess their classic role in spinal cord stability within the spinal canal.

Methods. Detailed observation of the denticulate ligaments in 12 adult cadavers was performed. Stress was applied in all major planes to discern when the ligaments would become taut, and at the same time, gross motion of the cord was observed at sites distal to the stresses applied. Tension necessary for avulsion of the ligaments in various areas of the spinal cord was also measured.

Conclusions. These results show that the denticulate ligaments do not inhibit cord motion to such discrete areas of the cord as was once thought. The authors have determined that the ligaments are stronger in the cervical region and that they decrease in strength as the spinal cord descends. These findings are demonstrative of the denticulate ligaments being more resistant to caudal compared with cephalad stresses in the cord. Anterior and posterior motion is constrained by these ligaments but to a limited degree, especially as one descends inferiorly along the cord. Further embryological and functional studies of these ligaments is needed in non—formalin fixed tissues.