Search Results

You are looking at 1 - 4 of 4 items for

  • Author or Editor: Greg Olavarria x
Clear All Modify Search
Full access

David I. Sandberg, John Ragheb, Catalina Dunoyer, Sanjiv Bhatia, Greg Olavarria and Glenn Morrison


In this study the authors review the outcomes in pediatric patients who presented with seizures and underwent resection of dysembryoplastic neuroepithelial tumors (DNETs). The authors focus on the diagnostic evaluation and surgical techniques that facilitate gross–total tumor resection and subsequent freedom from seizures.


Eighteen patients between the ages of 1 month and 13 years who presented with seizures underwent resection of DNETs between January 1992 and December 2004. Preoperative evaluation included magnetic resonance (MR) imaging and interictal scalp electroencephalography (EEG) in all patients, functional MR imaging in eight patients, video monitoring with ictal scalp EEG in 12 patients, interictal single-photon emission computerized tomography (SPECT) scanning in one patient, and ictal SPECT scanning in two patients. Thirteen patients underwent one-stage procedures, whereas five underwent two-stage procedures (implantation of monitoring electrodes followed by tumor resection), either for functional language mapping (three patients) or due to inconclusive preoperative data (two patients). Intraoperative electrocorticography (ECoG) was performed in 17 patients and led to resection of the cerebral cortex beyond the tumor margins in 10 of them. According to operative reports, gross–total tumor resections were achieved in all patients, but one child had minimal residual tumor on postoperative MR images that has remained stable. The only surgical complication was a transient third cranial nerve palsy. Over a median follow-up duration of 1.6 years, all patients are seizure free and without radiographically detected tumor recurrence.


Dysembryoplastic neuroepithelial tumors are a highly treatable cause of epilepsy in children. Excellent rates of complete tumor resection and seizure control with minimal morbidity can be attained using intraoperative ECoG and two-stage surgical procedures when appropriate.

Restricted access

Stacey Quintero Wolfe, Luisa Cervantes, Greg Olavarria, Carole Brathwaite, John Ragheb and Glenn Morrison

✓Desmoplastic fibromas are rare bone tumors that have been reported in the adult skull but rarely in that of children. Although desmoplastic fibromas of the pediatric skull are uncommon, their similarity to benign skull lesions and their locally aggressive nature make them an important part of the differential diagnosis. Local recurrence is common after curettage alone but complete resection appears to be curative. Close follow up of incompletely resected lesions is essential. The authors detail three cases of pediatric desmoplastic fibromas of the skull and discuss diagnosis and treatment.

Restricted access

Jennifer M. Strahle, Rukayat Taiwo, Christine Averill, James Torner, Chevis N. Shannon, Christopher M. Bonfield, Gerald F. Tuite, Tammy Bethel-Anderson, Jerrel Rutlin, Douglas L. Brockmeyer, John C. Wellons III, Jeffrey R. Leonard, Francesco T. Mangano, James M. Johnston, Manish N. Shah, Bermans J. Iskandar, Elizabeth C. Tyler-Kabara, David J. Daniels, Eric M. Jackson, Gerald A. Grant, Daniel E. Couture, P. David Adelson, Tord D. Alden, Philipp R. Aldana, Richard C. E. Anderson, Nathan R. Selden, Lissa C. Baird, Karin Bierbrauer, Joshua J. Chern, William E. Whitehead, Richard G. Ellenbogen, Herbert E. Fuchs, Daniel J. Guillaume, Todd C. Hankinson, Mark R. Iantosca, W. Jerry Oakes, Robert F. Keating, Nickalus R. Khan, Michael S. Muhlbauer, J. Gordon McComb, Arnold H. Menezes, John Ragheb, Jodi L. Smith, Cormac O. Maher, Stephanie Greene, Michael Kelly, Brent R. O’Neill, Mark D. Krieger, Mandeep Tamber, Susan R. Durham, Greg Olavarria, Scellig S. D. Stone, Bruce A. Kaufman, Gregory G. Heuer, David F. Bauer, Gregory Albert, Jeffrey P. Greenfield, Scott D. Wait, Mark D. Van Poppel, Ramin Eskandari, Timothy Mapstone, Joshua S. Shimony, Ralph G. Dacey Jr., Matthew D. Smyth, Tae Sung Park and David D. Limbrick Jr.


Scoliosis is frequently a presenting sign of Chiari malformation type I (CM-I) with syrinx. The authors’ goal was to define scoliosis in this population and describe how radiological characteristics of CM-I and syrinx relate to the presence and severity of scoliosis.


A large multicenter retrospective and prospective registry of pediatric patients with CM-I (tonsils ≥ 5 mm below the foramen magnum) and syrinx (≥ 3 mm in axial width) was reviewed for clinical and radiological characteristics of CM-I, syrinx, and scoliosis (coronal curve ≥ 10°).


Based on available imaging of patients with CM-I and syrinx, 260 of 825 patients (31%) had a clear diagnosis of scoliosis based on radiographs or coronal MRI. Forty-nine patients (5.9%) did not have scoliosis, and in 516 (63%) patients, a clear determination of the presence or absence of scoliosis could not be made. Comparison of patients with and those without a definite scoliosis diagnosis indicated that scoliosis was associated with wider syrinxes (8.7 vs 6.3 mm, OR 1.25, p < 0.001), longer syrinxes (10.3 vs 6.2 levels, OR 1.18, p < 0.001), syrinxes with their rostral extent located in the cervical spine (94% vs 80%, OR 3.91, p = 0.001), and holocord syrinxes (50% vs 16%, OR 5.61, p < 0.001). Multivariable regression analysis revealed syrinx length and the presence of holocord syrinx to be independent predictors of scoliosis in this patient cohort. Scoliosis was not associated with sex, age at CM-I diagnosis, tonsil position, pB–C2 distance (measured perpendicular distance from the ventral dura to a line drawn from the basion to the posterior-inferior aspect of C2), clivoaxial angle, or frontal-occipital horn ratio. Average curve magnitude was 29.9°, and 37.7% of patients had a left thoracic curve. Older age at CM-I or syrinx diagnosis (p < 0.0001) was associated with greater curve magnitude whereas there was no association between syrinx dimensions and curve magnitude.


Syrinx characteristics, but not tonsil position, were related to the presence of scoliosis in patients with CM-I, and there was an independent association of syrinx length and holocord syrinx with scoliosis. Further study is needed to evaluate the nature of the relationship between syrinx and scoliosis in patients with CM-I.