Development of shunt valves used for treating hydrocephalus: comparison with endoscopy treatment.

The pathophysiology of hydrocephalus is not clearly defined. Thus, treatment will remain empirical until a fuller understanding of the various forms of hydrocephalus is achieved. Valve-controlled shunting has been the mainstay of therapy since the late 1950s. Initially, shunting occurred from the ventricular system to the atrium. In the 1970s, VA shunts were replaced by ventriculoperitoneal shunts as the primary location for the distal end. Multiple types of one-way valve systems have been developed in the pursuit of draining the appropriate amount of CSF that avoids either overdrainage or underdrainage while preserving normal brain development and cognition. These valves are reviewed and compared as to their function. Other locations for the distal end of the shunting system are reviewed to include pleural space and gallbladder. The lumbar subarachnoid space as the proximal location for a shunt is also reviewed. The only other surgical alternative for treating hydrocephalus is endoscopic third ventriculostomy. Since 2000, approximately 50% of children with hydrocephalus have been shown to be candidates for ETV. The benefits are the lack of need for an artificial shunt system and thus lower rates of infection and over time fewer reoperations. Future progress is dependent on improved shunt valve systems that are affordable worldwide and ready availability of ETV in developing countries. Anatomic and molecular causes of hydrocephalus need to be defined so that medications or genetic modifications become available for potential cure of hydrocephalus.

Guidelines for the determination of brain death in infants and children: an update of the 1987 Task Force recommendations.

OBJECTIVE: To review and revise the 1987 pediatric brain death guidelines. METHODS: Relevant literature was reviewed. Recommendations were developed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system. CONCLUSIONS AND RECOMMENDATIONS: 1) Determination of brain death in term newborns, infants, and children is a clinical diagnosis based on the absence of neurologic function with a known irreversible cause of coma. Because of insufficient data in the literature, recommendations for preterm infants <37 wks gestational age are not included in this guideline. 2) Hypotension, hypothermia, and metabolic disturbances should be treated and corrected and medications that can interfere with the neurologic examination and apnea testing should be discontinued allowing for adequate clearance before proceeding with these evaluations. 3) Two examinations, including apnea testing with each examination separated by an observation period, are required. Examinations should be performed by different attending physicians. Apnea testing may be performed by the same physician. An observation period of 24 hrs for term newborns (37 wks gestational age) to 30 days of age and 12 hrs for infants and children (>30 days to 18 yrs) is recommended. The first examination determines the child has met the accepted neurologic examination criteria for brain death. The second examination confirms brain death based on an unchanged and irreversible condition. Assessment of neurologic function after cardiopulmonary resuscitation or other severe acute brain injuries should be deferred for ≥24 hrs if there are concerns or inconsistencies in the examination. 4) Apnea testing to support the diagnosis of brain death must be performed safely and requires documentation of an arterial Paco2 20 mm Hg above the baseline and ≥60 mm Hg with no respiratory effort during the testing period. If the apnea test cannot be safely completed, an ancillary study should be performed. 5) Ancillary studies (electroencephalogram and radionuclide cerebral blood flow) are not required to establish brain death and are not a substitute for the neurologic examination. Ancillary studies may be used to assist the clinician in making the diagnosis of brain death a) when components of the examination or apnea testing cannot be completed safely as a result of the underlying medical condition of the patient; b) if there is uncertainty about the results of the neurologic examination; c) if a medication effect may be present; or d) to reduce the interexamination observation period. When ancillary studies are used, a second clinical examination and apnea test should be performed and components that can be completed must remain consistent with brain death. In this instance, the observation interval may be shortened and the second neurologic examination and apnea test (or all components that are able to be completed safely) can be performed at any time thereafter. 6) Death is declared when these criteria are fulfilled.

Why do we behave as we do?

It is important for surgeons to have insight into themselves, their life stories, and the rationales they use to convince themselves that their actions are unselfish and well motivated. The battle between Philanthropia and Philotechnica was recognized by Hippocrates and is still a source of internal strife for many surgeons: the need to perform an operation that they are poorly equipped to do offset against the knowledge that it could be better done by someone else. In the treatment or referral for treatment of children with craniosynostosis and craniofacial syndromes, appropriate referrals are often not made or are made only after some problem has occurred as a result of surgical intervention. Several instances of children receiving extensive surgery for wrongly diagnosed craniosynostosis are explored. The thesis is that only by knowing our own internal motivations can we avoid falling into a posture that is good for our own egos and pocketbooks but bad for our patients.

Misidentification of vagus nerve stimulator for intravenous access and other major adverse events.

The vagus nerve stimulator has become a standard modality for intractable pediatric epilepsy. We reviewed our experience with major adverse events, after accidental puncture of a stimulator wire by an emergency room physician seeking intravenous access to treat status epilepticus. The Children's National Medical Center database was reviewed for patients undergoing vagus nerve stimulator placement between January 1988 and June 2006. Patient characteristics, duration of therapy, and treatment-limiting adverse events were noted. Of 62 patients implanted over 8 years, 22 (35%) had adverse events which led to a change in therapy. Adverse events included prominent drooling, coughing, throat discomfort, dysphagia, wound infection, difficulty breathing, vomiting, vocal-cord weakness, lead failure, and iatrogenic (piercing of wire; surgical clipping of wire during revision). Eight patients required nonroutine surgical intervention (13%). There were two unusual case presentations. In a 13-year-old boy with status epilepticus at an outlying emergency department, the stimulator line was pierced in search of intravenous access. In a 25-year-old housepainter, neck paresthesias upon right lateral neck turning were attributed to insufficient strain relief. Treatment-limiting adverse events occurred in approximately one-third of patients. Unanticipated adverse events included misidentification of the wire for intravenous access, clipping of the wire during surgical dissection, and cervical dysesthesias associated with head-turning.

Association of human herpesvirus-6B with mesial temporal lobe epilepsy.

BACKGROUND: Human herpesvirus-6 (HHV-6) is a beta-herpesvirus with 90% seroprevalence that infects and establishes latency in the central nervous system. Two HHV-6 variants are known: HHV-6A and HHV-6B. Active infection or reactivation of HHV-6 in the brain is associated with neurological disorders, including epilepsy, encephalitis, and multiple sclerosis. In a preliminary study, we found HHV-6B DNA in resected brain tissue from patients with mesial temporal lobe epilepsy (MTLE) and have localized viral antigen to glial fibrillary acidic protein (GFAP)-positive glia in the same brain sections. We sought, first, to determine the extent of HHV-6 infection in brain material resected from MTLE and non-MTLE patients; and second, to establish in vitro primary astrocyte cultures from freshly resected brain material and determine expression of glutamate transporters. METHODS AND FINDINGS: HHV-6B infection in astrocytes and brain specimens was investigated in resected brain material from MTLE and non-MTLE patients using PCR and immunofluorescence. HHV-6B viral DNA was detected by TaqMan PCR in brain resections from 11 of 16 (69%) additional patients with MTLE and from zero of seven (0%) additional patients without MTLE. All brain regions that tested positive by HHV-6B variant-specific TaqMan PCR were positive for viral DNA by nested PCR. Primary astrocytes were isolated and cultured from seven epilepsy brain resections and astrocyte purity was defined by GFAP reactivity. HHV-6 gp116/54/64 antigen was detected in primary cultured GFAP-positive astrocytes from resected tissue that was HHV-6 DNA positive-the first demonstration of an ex vivo HHV-6-infected astrocyte culture isolated from HHV-6-positive brain material. Previous work has shown that MTLE is related to glutamate transporter dysfunction. We infected astrocyte cultures in vitro with HHV-6 and found a marked decrease in glutamate transporter EAAT-2 expression. CONCLUSIONS: Overall, we have now detected HHV-6B in 15 of 24 patients with mesial temporal sclerosis/MTLE, in contrast to zero of 14 with other syndromes. Our results suggest a potential etiology and pathogenic mechanism for MTLE.

Bacterial adhesion to surfactant-modified silicone surfaces.

OBJECTIVE: Ventricular shunt infections are a major contributor to morbidity in patients being treated for hydrocephalus. The majority of these infections are from Staphylococcus epidermidis. Prevention of bacterial adhesion to the silicone surface of a ventricular catheter could decrease shunt infections. We studied the effectiveness of a surfactant and/or 2% iodine prewash on preventing bacterial adhesion to Silastic catheter material. METHODS: In a laboratory setting, various concentrations of a surfactant, Poloxamer-188 (P188), and a bactericidal agent, iodine, were compared against a control solution in their ability to prevent bacterial adhesion of S. epidermidis to a silicone surface. Silicone wafers were soaked for 1 hour in the test solution, then inoculated and incubated with S. epidermidis for 24 hours. Bacterial counts were then obtained and compared. RESULTS: The most effective method tested in this study was 20% P188, which allowed only 3.02% bacterial adhesion compared with 22.2% bacterial adhesion in the control (P < 0.001). P188 at a 10% concentration or 20% mixed with iodine had the next most effective inhibition. Of the germicidal solutions, a 5-ppm solution of iodine was the most effective. The most ineffective method tested was 2 ppm iodine, which allowed 13.2% bacterial adhesion. CONCLUSION: Use of a surfactant and/or a germicidal will provide some protection against bacteria attaching to silicone surfaces before they are surgically implanted. The use of a surfactant soak of 20% P188 or iodine at a concentration of 5 ppm before inoculation with S. epidermidis significantly decreased the bacterial adhesion to silicone wafers. This finding has relevance to clinical practice because it highlights a simple step undertaken before implanting a ventricular catheter that could reduce the adhesion rate of the most common contaminant of these catheters. This step may become an important factor in decreasing infection rates in shunt-dependent patients.

Hypothalamic ganglioglioma treated by temporal lobectomy. Case report and review of the literature.

The authors report the case of a hypothalamic ganglioglioma with left-sided temporal lobe extension in an 8-year-old girl who presented with seizures. Other cases of ganglioglioma involving the hypothalamus have been reported in the literature; however, this site of origin is exceedingly rare and worthy of report. Treatment involved medial temporal lobectomy with the hypothalamic component of the tumor remaining untouched. The patient recovered postoperatively with no neurological deficits and was seizure free at 12 months. Neither radio- nor chemotherapy was recommended because of the tumor histology, location, and the patient's age. The authors recommend follow up and surgical treatment for possible tumor recurrence. The prognosis for hypothalamic ganglioglioma is unknown.

Difficult questions facing the craniofacial team.

Children born with growth problems that affect the cranium or face require an initial correct diagnosis and appropriate specialty referral. Craniofacial surgery is a necessary and effective specialty that involves a multifaceted approach to the treatment of children with abnormal growth, deficient development, or traumatic or postnatal damage to the cranium and face. There are many unanswered questions concerning the treatment of these children that require ethical as well as scientific reflection by all involved in their care. Disagreements exist among the teams regarding both the timing of surgery and the best operative procedure. Reported mortality rates are 1-3% and all centers should have their own mortality and morbidity figures available for potential patients. Surgical interventions for craniosynostosis-regardless of whether it is isolated or syndromic-should not be undertaken lightly. These are major operations in infants and children. A complete multi-speciality team is necessary for comprehensive care of the children and their families. Which aspect of therapy; surgical, psychological, educational, speech or motor development is responsible for maximizing functional outcome for these children remains unclear and thus all possible services should be available.

Management of pilocytic astrocytoma with diffuse leptomeningeal spread: two cases and review of the literature.

INTRODUCTION: Leptomeningeal dissemination of juvenile pilocytic astrocytoma (JPA) is a rare event. We report two children with disseminated JPAs treated with a chemotherapeutic agent, temozolomide, after progression of the disease despite surgery, traditional chemotherapy, and/or radiation therapy. CASE REPORTS: Patient 1 presented with hydrocephalus and progressive lower extremity weakness, and was found to have a suprasellar mass as well as extensive spinal disease. Ventriculoperitoneal shunting, decompressive laminectomy with spinal tumor debulking, and chemotherapy with carboplatin and vincristine were initially employed. However, disease progressed and craniospinal irradiation and temozolomide were used. Patient 1 remains in a fair condition today, 2 years later. Patient 2 presented at 8 months of age with failure to thrive. Imaging revealed a cystic lesion in the hypothalamic region with extensive subarachnoid metastatic disease to the spine. Biopsy was performed followed by chemotherapy with vincristine, cyclohexylchloroethylnitrosourea (CCNU), 6-TG, and procarbazine. Due to the continued progression of the disease, cytoreductive surgery was performed and her chemotherapeutic regimen was switched to temozolomide. Two years after initial presentation patient 2 is clinically much improved with stable residual disease. DISCUSSION: We review the literature and discuss treatment strategies for this challenging disease.

Prognostic factors in children and adolescents with low-grade oligodendrogliomas.

Few reports exist describing the progression-free and overall survival of children with low-grade (WHO grade II) oligodendrogliomas treated uniformly with aggressive surgery but without adjuvant chemotherapy or radiation therapy. Furthermore, significant prognostic features, including the MIB-1 labeling index (LI), have not been reported for children with oligodendrogliomas. The medical records of 20 consecutive patients with low-grade oligodendrogliomas were reviewed. All patients had been treated with aggressive surgical resection. Adjuvant chemotherapy and radiation therapy were reserved for radiographic or clinical progression. These patients have been followed for a median of 5.5 years (range 0.5-11.5 years) after diagnosis. To date, there have been no patient deaths. Six of the 20 patients experienced tumor progression at a median of 2.2 years (range 0.4-4.8 years) following the initial surgery. The MIB-1 LI was infrequently greater than 5. Of several prognostic factors for subsequent tumor progression that were examined, only tumors located within the parietal lobes were associated with a worse progression-free survival. Other risk factors, including presenting symptoms, age at diagnosis, MIB-1 LI and the extent of tumor resection, were not associated with an increased frequency of tumor progression.