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Ryan P. Lee, Kimberly A. Foster, Jock C. Lillard, Paul Klimo Jr., David W. Ellison, Brent Orr, and Frederick A. Boop

OBJECTIVE

Thalamopeduncular tumors are a group of pediatric low-grade gliomas that arise at the interface of the thalamus and brainstem peduncle. They typically occur within the first 2 decades of life, presenting with progressive spastic hemiparesis. Treatment strategies, including surgical intervention, have varied significantly. The authors present their experience in the treatment of 13 children, ages 2–15 years, with non-neurofibromatosis–related pilocytic astrocytomas located in the thalamopeduncular region.

METHODS

Between 2003 and 2016, 13 children presenting with progressive spastic hemiparesis due to a pilocytic astrocytoma at the interface of the thalamus and cerebral peduncles were identified. Medical records were reviewed retrospectively for clinical, radiological, pathological, and surgical data. Formalin-fixed, paraffin-embedded tissue was obtained for 12 cases and tested for KIAA1549-BRAF fusion and BRAF V600E point mutation.

RESULTS

On preoperative diffusion tensor imaging tractography (performed in 12 patients), the ipsilateral corticospinal tract was displaced laterally in 1 case (8.3%), medially in 1 case (8.3%), anterolaterally in 10 cases (83%), and posteriorly in no cases. Ten patients underwent resection via a transtemporal, transchoroidal approach, which was chosen to avoid further damage to motor function in cases of tumors that caused anterolateral or medial corticospinal tract displacement. With this approach, complications included hemianopia, oculomotor palsy, and tremor at a rate of 50%. Among the 12 patients with obtainable follow-up (mean 50.9 months), none received adjuvant therapy, and only 2 (17%) experienced recurrence or progression. KIAA1549-BRAF fusions were present in 10 cases (83%), while BRAF V600E was absent (0%). The 2 fusion-negative tumors had clinical features atypical for the series, including multi-focality and infiltration.

CONCLUSIONS

Transcortical, transchoroidal resection of thalamopeduncular tumors through the middle temporal gyrus allows for a high rate of gross-total resection and cure. Diffuse tensor tractography is a critical component of the preoperative planning process to determine the location of white matter tracts in proximity. Molecular status may correlate with clinical features, and the presence of BRAF lesions offers an additional target for future novel therapeutics.

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Akshitkumar M. Mistry, Nishit Mummareddy, Travis S. CreveCoeur, Jock C. Lillard, Brandy N. Vaughn, Jean-Nicolas Gallant, Andrew T. Hale, Natalie Griffin, John C. Wellons III, David D. Limbrick Jr., Paul Klimo Jr., and Robert P. Naftel

OBJECTIVE

The subventricular zone (SVZ), housed in the lateral walls of the lateral ventricles, is the largest neurogenic niche in the brain. In adults, high-grade gliomas in contact or involved with the SVZ are associated with decreased survival. Whether this association holds true in the pediatric population remains unexplored. To address this gap in knowledge, the authors conducted this retrospective study in a pediatric population with high-grade gliomas treated at three comprehensive centers in the United States.

METHODS

The authors retrospectively identified 63 patients, age ≤ 21 years, with supratentorial WHO grade III–IV gliomas treated at three academic centers. Basic demographic and clinical data regarding presenting signs and symptoms and common treatment variables were obtained. Preoperative MRI studies were evaluated to assess SVZ contact by tumor and to quantify tumor volume.

RESULTS

Sixty-three patients, including 34 males (54%), had a median age of 12.3 years (IQR 6.50–16.2) and a median tumor volume of 39.4 ml (IQR 19.4–65.8). Tumors contacting the SVZ (SVZ+) were noted in 34 patients (54%) and overall were larger than those not in contact with the SVZ (SVZ−; 51.1 vs 27.3, p = 0.002). The SVZ+ tumors were also associated with decreased survival. However, age, tumor volume, tumor grade, and treatment with chemotherapy and/or radiation were not associated with survival in the 63 patients. In the univariable analysis, near-total resection, gross-total resection, and seizure presentation were associated with increased survival (HR = 0.23, 95% CI 0.06–0.88, p = 0.03; HR = 0.26, 95% CI 0.09–0.74, p = 0.01; and HR = 0.46, 95% CI 0.22–0.97, p = 0.04, respectively). In a multivariable stepwise Cox regression analysis, only SVZ+ tumors remained significantly associated with decreased survival (HR = 1.94, 95% CI 1.03–3.64, p = 0.04).

CONCLUSIONS

High-grade glioma contact with the SVZ neural stem cell niche was associated with a significant decrease in survival in the pediatric population, as it is in the adult population. This result suggests that tumor contact with the SVZ is a general negative prognosticator in high-grade glioma independent of age group and invites biological investigations to understand the SVZ’s role in glioma pathobiology.

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Ryan P. Lee, Raymond Xu, Pooja Dave, Sonia Ajmera, Jock C. Lillard, David Wallace, Austin Broussard, Mustafa Motiwala, Sebastian Norrdahl, Carissa Howie, Oluwatomi Akinduro, Garrett T. Venable, Nickalus R. Khan, Douglas R. Taylor, Brandy N. Vaughn, and Paul Klimo Jr.

OBJECTIVE

There has been an increasing interest in the quantitative analysis of publishing within the field of neurosurgery at the individual, group, and institutional levels. The authors present an updated analysis of accredited pediatric neurosurgery training programs.

METHODS

All 28 Accreditation Council for Pediatric Neurosurgery Fellowship programs were contacted for the names of pediatric neurosurgeons who were present each year from 2011 through 2015. Faculty names were queried in Scopus for publications and citations during this time period. The 5-year institutional Hirsch index [ih(5)-index] and revised 5-year institutional h-index [ir(5)-index] were calculated to rank programs. Each publication was reviewed to determine authorship value, tier of research, clinical versus basic science research, subject matter, and whether it was pediatrics-specific. A unique 3-tier article classification system was introduced to stratify clinical articles by quality and complexity, with tier 3 being the lowest tier of publication (e.g., case reports) and tier 1 being the highest (e.g., randomized controlled trials).

RESULTS

Among 2060 unique publications, 1378 (67%) were pediatrics-specific. The pediatrics-specific articles had a mean of 15.2 citations per publication (median 6), whereas the non–pediatrics-specific articles had a mean of 23.0 citations per publication (median 8; p < 0.0001). For the 46% of papers that had a pediatric neurosurgeon as first or last author, the mean number of citations per publication was 12.1 (median 5.0) compared with 22.5 (median 8.0) for those in which a pediatric neurosurgeon was a middle author (p < 0.0001). Seventy-nine percent of articles were clinical research and 21% were basic science or translational research; however, basic science and translational articles had a mean of 36.9 citations per publication (median 15) compared with 12.6 for clinical publications (median 5.0; p < 0.0001). Among clinical articles, tier 1 papers had a mean of 15.0 citations per publication (median 8.0), tier 2 papers had a mean of 18.7 (median 8.0), and tier 3 papers had a mean of 7.8 (median 3.0). Neuro-oncology papers received the highest number of citations per publication (mean 25.7). The most common journal was the Journal of Neurosurgery: Pediatrics (20%). MD/PhD faculty members had significantly more citations per publication than MD faculty members (mean 26.7 vs 14.0; p < 0.0001) and also a higher number of publications per author (mean 38.6 vs 20.8). The median ih(5)- and ir(5)-indices per program were 14 (range 5–48) and 10 (range 5.6–37.2), respectively. The mean ir(5)/ih(5)-index ratio was 0.8. The top 5 fellowship programs (in descending order) as ranked by the ih(5)-index corrected for number of faculty members were The Hospital for Sick Children, Toronto; Children’s Hospital of Pittsburgh; University of California, San Francisco Benioff Children’s Hospital; Seattle Children’s Hospital; and St. Louis Children’s Hospital.

CONCLUSIONS

About two-thirds of publications authored by pediatric neurosurgeons are pediatrics-specific, although non–pediatrics-specific articles averaged more citations. Most of the articles authored by pediatric neurosurgeons are clinical, with basic and translational articles averaging more citations. Neurosurgeons with PhD degrees averaged more total publications and more citations per publication. In all, this is the most advanced and informative analysis of publication productivity in pediatric neurosurgery to date.