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Paul Klimo Jr. and John R. W. Kestle

✓The choice of outcome (or outcomes) and their measurement are critical for a sound clinical trial. Surgeons have traditionally measured simple outcomes such as death, duration of survival, or tumor recurrence but have recently developed more sophisticated measures of the effect of an intervention. Many outcome measures require a lengthy maturation process, which includes a determination of the instrument's validity, reliability, and sensitivity; thus, using established instruments rather than creating new ones is recommended. The authors illustrate several guidelines for the determination of appropriate outcome measures by using examples from their experience and describe several outcome measures that can be used in pediatric neurosurgery. These include general outcome measures such as the Pediatric Evaluation of Disability Inventory and the Functional Independence Measure for Children, which measure physical function and independence in chronically ill and disabled children as well as disease-specific measures for hydrocephalus (Hydrocephalus Outcome Questionnaire), cerebral palsy (gross motor function and performance measures), head injury (Pediatric Cerebral Performance Category and Children's Coma Scale), and oncology (Pediatric Cancer Quality-of-Life Inventory).

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John R. W. Kestle, Harold J. Hoffman and Antonio R. Mock

✓ The role of radiotherapy in the management of patients with optic pathway glioma is controversial. In a series of patients with optic pathway glioma treated at The Hospital for Sick Children in Toronto, five children were encountered who developed moyamoya phenomenon after radiotherapy. A retrospective review of the medical records was undertaken in order to assess the relationship between optic pathway glioma, neurofibromatosis type 1 (NF1), radiation therapy, and moyamoya disease.

Forty-seven patients with optic pathway glioma were operated on at The Hospital for Sick Children between 1971 and 1990. The moyamoya phenomenon did not occur in any of the 19 patients not receiving radiotherapy. Among the 28 patients who received radiotherapy, five developed moyamoya disease (two of 23 without NF1 and three of five with NF1). There was a statistically significant relationship between radiotherapy and moyamoya disease when the analysis was stratified according to the presence of NF1 (Mantel-Haensel chi-squared test 15.23, p < 0.01). The high incidence of moyamoya disease (three of five cases, or 60%) in patients with NF1 who have undergone radiotherapy suggests a synergistic relationship that should be considered when formulating a treatment plan for NF1 patients with optic pathway glioma.

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Daniel R. Fassett, James Pingree and John R. W. Kestle

P Myxopapillary ependymomas (MPEs) have historically been thought to be benign tumors occurring most frequently in adults. Only 8 to 20% of these tumors occur in the first two decades of life, making this tumor a rarity in pediatric neurosurgery. Five patients with intraspinal MPEs were treated by the authors between 1992 and 2003. Four (80%) of these five patients suffered from disseminated disease of the central nervous system (CNS) at the time of presentation; this incidence is much higher than that reported in the combined adult and pediatric literature.

Combining five pediatric case series reported in the literature with the present series, the authors review a total of 26 cases of pediatric patients with intraspinal MPEs. In nine cases (35%) CNS metastases occurred. In those cases in which patients underwent screening for CNS tumor dissemination, however, the incidence of disseminated disease was 58% (seven of 12 patients).

In pediatric patients MPEs may spread throughout the CNS via cerebrospinal fluid pathways; therefore, MR imaging of the entire CNS axis is recommended at both presentation and follow-up review to detect tumor dissemination.

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R. Loch Macdonald, M. Christopher Wallace and John R. W. Kestle

✓ The postoperative angiograms in 66 patients who underwent craniotomy for clipping of 78 cerebral aneurysms were reviewed. Indications for urgent postoperative angiography included neurological deficit or repeat subarachnoid hemorrhage. Routine postoperative angiograms were carried out in the remaining patients. Postoperative angiograms were reviewed to determine the incidence of unexpected findings such as unclipped aneurysms, residual aneurysms, and unforeseen major vessel occlusions. Logistic regression analysis was used to test if the following were factors that predicted an unexpected finding on postoperative angiography: aneurysm site or size; the intraoperative impression that residual aneurysm was left or a major vessel was occluded; intraoperative aneurysm rupture; opening or needle aspiration of the aneurysm after clipping; or development of a new neurological deficit after surgery. Kappa values were calculated to assess the agreement between some of these clinical factors and unexpected angiographic findings.

Unexpected residual aneurysms were seen in three (4%) of the 78 occlusions. In addition, three aneurysms were completely unclipped (4%); these three patients were returned to the operating room and had their aneurysms successfully obliterated. There were nine unexpected major vessel occlusions (12%); six of these resulted in disabling stroke and two patients died. Of six major arteries considered to be occluded intraoperatively and shown to be occluded by postoperative angiography, two were associated with cerebral infarction. Logistic regression analysis showed that a new postoperative neurological deficit predicted an unforeseen vessel occlusion on postoperative angiography. Factors could not be identified that predicted unexpected residual aneurysm or unclipped aneurysm.

The inability to predict accurately the presence of residual or unclipped aneurysm suggests that all patients should undergo postoperative angiography. Since a new postoperative neurological deficit is one factor predicting unexpected arterial occlusion, intraoperative angiography may be necessary to help reduce the incidence of stroke after aneurysm surgery. With study of more patients or of factors not examined in this series, it may be possible to select cases more accurately for intraoperative or postoperative angiography.

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Chittur Viswanathan Gopalakrishnan, John R. W. Kestle and Mary B. Connolly

A 16-year-old boy underwent vagus nerve stimulation for treatment-resistant multifocal epilepsy. During intraoperative system diagnostics, vigorous contraction of the ipsilateral sternomastoid muscle was observed. On re-exploration, a thin nerve fiber passing from the vagus to the sternomastoid was found hooked up in the upper electrode. Detailed inspection revealed an abnormal course of the superior root of the ansa cervicalis, which descended down as a single nerve trunk with the vagus and separated to join the inferior root. The authors discuss the variation in the course of the ansa cervicalis and how this could be a reason for postoperative neck muscle contractions.

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John R. W. Kestle, Abhaya V. Kulkarni and Benjamin C. Warf

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Todd D. McCall, James K. Liu and John R. W. Kestle

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John R. W. Kestle

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Prospective multicenter studies in pediatric hydrocephalus

JNSPG 75th Anniversary Invited Review Article

John R. W. Kestle and Jay Riva-Cambrin

Prospective multicenter clinical research studies in pediatric hydrocephalus are relatively rare. They cover a broad spectrum of hydrocephalus topics, including management of intraventricular hemorrhage in premature infants, shunt techniques and equipment, shunt outcomes, endoscopic treatment of hydrocephalus, and prevention and treatment of infection. The research methodologies include randomized trials, cohort studies, and registry-based studies. This review describes prospective multicenter studies in pediatric hydrocephalus since 1990. Many studies have included all forms of hydrocephalus and used device or procedure failure as the primary outcome. Although such studies have yielded useful findings, they might miss important treatment effects in specific subgroups. As multicenter study networks grow, larger patient numbers will allow studies with more focused entry criteria based on known and evolving prognostic factors. In addition, increased use of patient-centered outcomes such as neurodevelopmental assessment and quality of life should be measured and emphasized in study results. Well-planned multicenter clinical studies can significantly affect the care of children with hydrocephalus and will continue to have an important role in improving care for these children and their families.

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Shobhan Vachhrajani, Abhaya V. Kulkarni and John R. W. Kestle

In the era of evidence-based medicine, clinical practice guidelines (CPGs) have become an integral part of many aspects of medical practice. Because practicing neurosurgeons rarely have the time or, in some cases, the methodological expertise, to assess and assimilate the totality of primary research, CPGs can in theory provide a vehicle through which neurosurgeons could more efficiently integrate the most current evidence into patient management. Clinical practice guidelines have been met with some skepticism, however, particularly within the neurosurgical community. Some have expressed concerns that the promise of CPGs has not been matched by the reality. Others who oppose CPGs fear that they hinder the art of medicine, and limit physician and patient autonomy. The purpose of this paper is to provide the practicing neurosurgeon with an up-to-date review of CPGs. The authors discuss some of the complexities and recent advancements in CPG development, appraisal, and publication. An overview of the various systems for grading medical evidence and issuing CPG recommendations, each of which has its advantages and disadvantages, is included, and the current knowledge on the impact of CPGs in 2 important realms, patient care and medicolegal issues, is discussed.

The purpose of this review is to provide a balanced, current synopsis of what CPGs are, how they are developed, and what they can and cannot do. The authors hope that this will allow neurosurgeons to make more informed decisions about the many CPGs that will inevitably become an essential component of medical practice in the years to come.