George I Jallo

Johns Hopkins University, Baltimore, MD, USA

Are you George I Jallo?

Claim your profile

Publications (119)254.73 Total impact

  • Article: Complications and subsequent removal of retained shunt hardware after endoscopic third ventriculostomy: case series.
    Jonathan Pindrik, George I Jallo, Edward S Ahn
    [show abstract] [hide abstract]
    ABSTRACT: This case series highlights multiple complications and subsequent removal of retained shunt hardware in pediatric patients after successful endoscopic third ventriculostomy (ETV). Removal or retention of existing shunt hardware following ETV represents an important dilemma. Prior studies have reported infections and organ perforation related to nonfunctioning shunts but none in the context of successful ETV. Data obtained in 3 children with hydrocephalus treated at the authors' institution were retrospectively reviewed after the patients experienced complications due to retained shunt hardware following ETV. Etiologies of hydrocephalus included tectal glioma and intraventricular hemorrhage. All 3 patients had a history of multiple shunt revisions and underwent urgent ETV in the setting of a shunt malfunction. In each case, the entire shunt system was left in situ, but it became the source of subsequent complications. Two of the 3 patients presented with the shunt infected by gram-negative bacilli 10 days and 4.5 months postoperatively, respectively. The remaining patient experienced wound dehiscence over the shunt valve 4.5 months after ETV. In all patients, the complications were managed successfully by removing the shunt hardware. None of the patients required repeat shunt insertion from the time of removal throughout the follow-up period (mean 24 months, range 9-36 months). During the study period, a total of 6 patients with indwelling shunt hardware underwent ETV with the expectation of being shunt independent. Among these 6 patients, 3 experienced no complications from the retained hardware whereas 3 patients (50%) ultimately experienced adverse consequences related to retained hardware. This case series illustrates complications involving retained shunt hardware after successful ETV. These examples support consideration of shunt removal at the time of ETV in the appropriate context.
    Journal of Neurosurgery Pediatrics 04/2013; · 1.53 Impact Factor
  • Article: TERT promoter mutations occur frequently in gliomas and a subset of tumors derived from cells with low rates of self-renewal.
    [show abstract] [hide abstract]
    ABSTRACT: Malignant cells, like all actively growing cells, must maintain their telomeres, but genetic mechanisms responsible for telomere maintenance in tumors have only recently been discovered. In particular, mutations of the telomere binding proteins alpha thalassemia/mental retardation syndrome X-linked (ATRX) or death-domain associated protein (DAXX) have been shown to underlie a telomere maintenance mechanism not involving telomerase (alternative lengthening of telomeres), and point mutations in the promoter of the telomerase reverse transcriptase (TERT) gene increase telomerase expression and have been shown to occur in melanomas and a small number of other tumors. To further define the tumor types in which this latter mechanism plays a role, we surveyed 1,230 tumors of 60 different types. We found that tumors could be divided into types with low (<15%) and high (≥15%) frequencies of TERT promoter mutations. The nine TERT-high tumor types almost always originated in tissues with relatively low rates of self renewal, including melanomas, liposarcomas, hepatocellular carcinomas, urothelial carcinomas, squamous cell carcinomas of the tongue, medulloblastomas, and subtypes of gliomas (including 83% of primary glioblastoma, the most common brain tumor type). TERT and ATRX mutations were mutually exclusive, suggesting that these two genetic mechanisms confer equivalent selective growth advantages. In addition to their implications for understanding the relationship between telomeres and tumorigenesis, TERT mutations provide a biomarker that may be useful for the early detection of urinary tract and liver tumors and aid in the classification and prognostication of brain tumors.
    Proceedings of the National Academy of Sciences 03/2013; · 9.68 Impact Factor
  • Article: The periumbilical approach in ventriculoperitoneal shunt placement: technique and long-term results.
    [show abstract] [hide abstract]
    ABSTRACT: Object The aim of this study was to examine the feasibility and safety of ventriculoperitoneal (VP) shunt placement using a periumbilical approach for distal peritoneal access. By using this minimally invasive approach, the authors hypothesized that the cosmetic outcomes would be better than could be achieved by using a traditional minilaparotomy and that clinical results would be comparable. Methods A periumbilical approach was used for distal catheter insertion during a first-time VP shunt placement in 20 patients (8 males and 12 females). Median age at time of surgery was 3.0 months (range 7 days-11.9 years) and mean follow-up time was 17.8 months (range 1.2-28.0 months). The median weight of the patients was 3.99 kg (range 1.95-57.0 kg). A single incision was made along the natural crease inferior to the umbilicus. The linea alba was exposed and a 1-mm incision made while the patient was temporarily held in a Valsalva maneuver. A peritoneal trocar was then inserted through the fascial incision and the distal catheter was passed into the peritoneal space. Results The incision line in all patients healed well, did not require operative revision, and was described as minimally visible by the patients' families. Mean operative time was 35 minutes. Eight patients required revision surgery. One distal failure occurred when the distal shunt tubing retracted and became coiled in the neck; this was repaired by conversion to a minilaparotomy for distal replacement. There was 1 shunt infection (5%) requiring shunt removal and replacement. One patient had significant skin thinning around the valve and proximal catheter, which required replacement of the entire shunt system, and another patient underwent a conversion to a ventriculoatrial shunt due to poor peritoneal absorption. In the remaining 4 patients who required operative revision, the peritoneal portion of the shunt was not involved. Conclusions The periumbilical approach for peritoneal access during VP shunt placement is technically feasible, has low infection rates, and has cosmetically appealing results. It may be considered as an alternative option to standard VP shunt placement techniques.
    Journal of Neurosurgery Pediatrics 02/2013; · 1.53 Impact Factor
  • Article: Management of Pediatric Spinal Cord Astrocytomas: Outcomes With Adjuvant Radiation.
    [show abstract] [hide abstract]
    ABSTRACT: PURPOSE: Pediatric intramedullary spinal cord tumors are exceedingly rare; in the United States, 100 to 200 cases are recognized annually, of these, most are astrocytomas. The purpose of this study is to report the outcomes in pediatric patients with spinal cord astrocytomas treated at a tertiary care center. METHODS AND MATERIALS: An institutional review board-approved retrospective single-institution study was performed for pediatric patients with spinal cord astrocytomas treated at our hospital from 1990 to 2010. The patients were evaluated on the extent of resection, progression-free survival (PFS), and development of radiation-related toxicities. Kaplan-Meier curves and multivariate regression model methods were used for analysis. RESULTS: Twenty-nine patients were included in the study, 24 with grade 1 or 2 (low-grade) tumors and 5 with grade 3 or 4 (high-grade) tumors. The median follow-up time was 55 months (range, 1-215 months) for patients with low-grade tumors and 17 months (range, 10-52 months) for those with high-grade tumors. Thirteen patients in the cohort received chemotherapy. All patients underwent at least 1 surgical resection. Twelve patients received radiation therapy to a median radiation dose of 47.5 Gy (range, 28.6-54.0 Gy). Fifteen patients with low-grade tumors and 1 patient with a high-grade tumor exhibited stable disease at the last follow-up visit. Acute toxicities of radiation therapy were low grade, whereas long-term sequelae were infrequent and manageable when they arose. All patients with low-grade tumors were alive at the last follow-up visit, compared with 1 patient with a high-grade tumor. CONCLUSION: Primary pediatric spinal cord astrocytomas vary widely in presentation and clinical course. Histopathologic grade remains a major prognostic factor. Patients with low-grade tumors tend to have excellent disease control and long-term survival compared to those with high-grade tumors. This experience suggests that radiation therapy may enhance tumor control with an acceptably low risk of long-term sequelae in this sensitive patient population.
    International journal of radiation oncology, biology, physics 02/2013; · 4.59 Impact Factor
  • Article: Novel use of an ultrasonic bone-cutting device for endoscopic-assisted craniosynostosis surgery.
    [show abstract] [hide abstract]
    ABSTRACT: PURPOSE: Endoscopic-assisted craniosynostosis surgery is associated with less blood loss and shorter operative times as compared to open surgery. However, in infants who have low circulating blood volumes, the endoscopic approach is still associated with significant blood loss. A major source of blood loss is the bone that is cut during surgery. We discuss the novel use of an ultrasonic bone-cutting device for craniosynostosis surgery, which decreases bone bleeding. This device, which has primarily only been used for spine and skull base surgery, may help reduce blood loss in these infants. METHODS: All patients with single suture craniosynostosis who were operated on with the use of an ultrasonic bone-cutting device were identified. The information retrospectively recorded from patient charts included patient age, suture involved, blood loss, operative times, complications, preoperative hemoglobin, postoperative hemoglobin, length of hospital stay, and follow-up times. RESULTS: Thirteen patients (12 males, 1 female) underwent surgery with an ultrasonic bone-cutting device during the reviewed period. The average age (±standard deviation) of the patients was 11.8 (±1.6) weeks. Four patients had metopic synostosis and nine patients had sagittal synostosis. The average surgery time was 84 (±13) min. The median (interquartile range) blood loss was 20 (10-70) cc. No patients required blood transfusions. Three patients had dural tears. CONCLUSION: We demonstrate the novel use of an ultrasonic bone-cutting device for endoscopic-assisted craniosynostosis surgery. This device limited blood loss while maintaining short operative times for infants with low circulating blood volumes.
    Child s Nervous System 02/2013; · 1.54 Impact Factor
  • Article: Pediatric spinal tumors.
    Wesley Hsu, George I Jallo
    [show abstract] [hide abstract]
    ABSTRACT: Although tumors of the central nervous system in children constitute the second most prevalent tumor type of childhood, spinal cord tumors account for less than 10% of pediatric central nervous system tumors. The most common are intramedullary, although they can be found in the extradural compartment or as intradural extramedullary masses. Extradural tumors can arise from bony elements, the meninges, or soft tissues. Neuroblastomas and sarcomas are frequently encountered along with bone tumors. Intradural extramedullary tumors can be meningeal or from distant sites and include meningiomas and schwannomas; most tend to be benign. Intradural intramedullary tumors, neuronal or glial, can be derived from neuroepithelial tissues. For the intramedullary tumors, astrocytomas represent around 60% of tumors, ependymomas 30%, and developmental tumors 4%. Such tumors require a multidisciplinary approach to ensure optimal patient outcomes. Spinal cord tumors most often present with pain followed by motor regression, gait disturbance, sphincter dysfunction or sensory loss, torticollis, and kyphoscoliosis. Treatment is based on tumor type, but surgical resection is the mainstay. Predictors of outcome include the histological grading, extent of resection, and neurological status at the time of surgery.
    Handbook of Clinical Neurology 01/2013; 112:959-65.
  • Article: Ultrasonic Bone Scalpel for Osteoplastic Laminoplasty in the Resection of Intradural Spinal Pathology: Case Series and Technical Note.
    [show abstract] [hide abstract]
    ABSTRACT: BACKGROUND:: Osteoplastic laminoplasty is a well-described technique that may decrease the incidence of progressive kyphosis when used in the setting of intradural spinal cord tumor resection. OBJECTIVE:: The BoneScalpel™ by Aesculap is an ultrasonic osteotome that precisely cuts bone while preserving the underlying soft tissues, potentially reducing the risk of dural laceration during laminoplasty. By producing osteotomies as narrow as 0.5 mm, the device may also facilitate post-operative osteointegration. METHODS:: A retrospective analysis was conducted of 40 patients (mean age: 38.0 years, range: 4.0-79.7 years) who underwent osteoplastic laminoplasty using the BoneScalpel™ for the treatment of intradural spinal pathology at the Johns Hopkins Hospital between January 2009 and December 2011. Following lesion resection, titanium plates were used to reconstruct the lamina in all cases. The technical results and procedure-related complications were subsequently noted. RESULTS:: Successful laminoplasty was carried out in all 40 cases. Intraoperatively, one case of incidental durotomy was noted following use of the device, which was repaired primarily without neurological or clinical sequelae. During the follow-up period (mean: 195 days, median: 144 days), there were 2 complications (CSF leak=1, seroma=1) and no cases of immediate post-operative instability. CONCLUSION:: The BoneScalpel™ by Aesculap is a safe and technically feasible device for performing osteoplastic laminoplasty.
    Neurosurgery 12/2012; · 2.79 Impact Factor
  • Article: Posthemorrhagic Hydrocephalus in Preterm Neonates: Socioeconomic Characteristics in a Single-Institution Experience.
    [show abstract] [hide abstract]
    ABSTRACT: Patients with posthemorrhagic hydrocephalus (PHH) from germinal matrix hemorrhage of prematurity often require numerous early interventions, as well as long-term follow-up care from pediatric neurosurgeons, which continues to place high demands on the existing workforce and pediatric health care system. There are established correlations between premature birth and low socioeconomic status. The aim of this study is to characterize the demographic profile and follow-up patterns in this subpopulation of surgically treated infants with PHH from prematurity. Methods: A retrospective analysis of the electronic patient records for a single institution, from 2007 to 2010, was performed. All patients who underwent neurosurgical intervention for the treatment of PHH were selected for further analysis. Data elements available within the records included patient demographic features, inpatient treatments and procedures, inpatient mortality rates, length of stay, and postoperative follow-up at the institution. Socioeconomic status was assessed using the median household income for the patient's zip code, as reported in the United States Census for the year 2000. Results: A total of 40 patients who underwent neurosurgical intervention for PHH at a single institution were identified. More patients were female (52.5%); the majority of patients were Black (57.5%). No patients were uninsured; most patients had public insurance (62.5%), and 65% were below the Maryland State median household income (USD 52,868). There were trends toward more frequent emergency room visits among those covered by public insurance and those below the state and national median house income, although differences were not statistically significant. Conclusions: Our data indicate that the majority of patients fall within lower household income brackets, are born into households earning less than the statewide median household income, and are covered by public insurance. In light of the socioeconomic profile of the patient population reported here, these data may prove to be useful in preventative strategies aimed toward prematurity, PHH, and the ongoing treatment of hydrocephalus by pediatric neurosurgeons and other pediatric subspecialists.
    Pediatric Neurosurgery 09/2012; · 0.70 Impact Factor
  • Article: Treatment of choroid plexus tumors: a 20-year single institutional experience.
    [show abstract] [hide abstract]
    ABSTRACT: Object Choroid plexus tumors (CPTs) are rare intracranial neoplasms that constitute approximately 2%-5% of all pediatric brain tumors. Most of these tumors present with severe hydrocephalus. The optimal perioperative management and oncological care remain a matter of debate. The authors present the epidemiological and clinical features of CPTs from a 20-year single-institutional experience. Methods A total of 39 consecutive patients with pathologically proven CPTs (31 choroid plexus papillomas [CPPs] and 8 choroid plexus carcinomas [CPCs]) were included in this series. Patient demographics, clinical presentation, comorbidities, indications for surgery, radiological studies, tumor location, and all operative variables were reviewed for each case. Multivariate regression analysis was performed to identify independent predictors of tumor recurrence and survival. Results The overall mean age (± SD) was 13.13 ± 19.59 years (15.27 ± 21.10 years in the CPP group and 3.66 ± 3.59 years in the CPC group). Hydrocephalus was noted at presentation in 34% of patients. The most common presenting symptoms were headache (32%) and nausea/vomiting (26%). Gross-total resection (GTR) was achieved in 86% of CPPs and in 71% of CPCs (p = 0.57). There was 100% survival in patients with CPPs observed at the 5- and 10-year follow-up and 71% survival in patients with CPCs at the 5-year follow-up. In a multivariate regression analysis, a diagnosis of papilloma, preoperative vision changes, or hydrocephalus; right ventricle tumor location; and GTR were all independently associated with a decreased likelihood of tumor recurrence at last follow-up. Conclusions The authors' study suggests that patients with CPCs are more likely to experience local recurrence and metastasis; hence, GTR with chemotherapy and radiotherapy, particularly for CPCs, is pivotal in preventing recurrence and prolonging survival. While GTR was important for local control following resection of CPPs, it had a minimal effect on prolonging survival in this patient cohort.
    Journal of Neurosurgery Pediatrics 08/2012; · 1.53 Impact Factor
  • Article: Prognostic factors and survival in primary malignant astrocytomas of the spinal cord: a population-based analysis from 1973 to 2007.
    [show abstract] [hide abstract]
    ABSTRACT: Observational cross-sectional study. Using data from the population-based cancer registries of the Surveillance, Epidemiology and End Results (SEER) program, we analyzed demographic features, tumor and treatment characteristics, as well as survival rates in patients with primary malignant astrocytomas of the spinal cord (PMASC). PMASC is a rare neoplasm and is considered to carry the same dismal outcome as their cerebral counterparts. Our current knowledge is incomplete, and understanding the epidemiology, diagnosis, and optimal treatment still poses challenges. The SEER data from 1973 to 2007 were reviewed for pathologically confirmed primary anaplastic astrocytomas (AA) and glioblastomas of the spinal cord (C72.0). We compared the clinical features and outcomes of the cohort in uni- and multivariate fashion. Survival was calculated and compared using Kaplan-Meier curves and log-rank analysis. Our search criteria retrieved 135 patients diagnosed with PMASC. The median survival for PMASC was 13 months with 1-, 2-, and 5-year survival rates of 51.8%, 32.2%, and 18.7%. Patient diagnosed with AA had a median survival time of 17 months versus 10 months in patients diagnosed with glioblastomas. Adult patients observed markedly prolonged survival compared with the pediatric group, with a 16-month versus 9-month median survival, respectively. Multivariate analysis revealed age at diagnosis, pediatric and adult age groups, sex, tumor histology, and extent of resection as significant predictors of survival. Interestingly, outcomes did not significantly change throughout the last decades or by receiving radiotherapy. Outcome for patients diagnosed with PMASC remains poor and presents an ongoing challenge for professionals in the field of neurospinal medicine and surgery. In our analyses of AA, adult patients, males, and patients undergoing radical resections were associated with increased survival. However, incidence of these lesions is low; hence, building strong collaborative, interdisciplinary, and multi-institutional study groups is necessary to define the optimal treatment of PMASC.
    Spine 05/2012; 37(12):E727-35. · 2.08 Impact Factor
  • Article: Favorable outcome with conservative treatment for children with low grade brainstem tumors.
    Andrew W Walter, George I Jallo
    Pediatric Blood & Cancer 03/2012; 59(3):591. · 1.89 Impact Factor
  • Article: The effects of temozolomide delivered by prolonged intracerebral microinfusion against the rat brainstem GBM allograft model.
    [show abstract] [hide abstract]
    ABSTRACT: Diffuse intrinsic brainstem gliomas are considered to be inoperable. We report our initial experience of temozolomide (TMZ) administration into brainstem by intracerebral (i.c.) microinfusion using a rat brainstem glioblastoma allograft model. Forty-eight Fischer 344 female rats were used. In a feasibility study, various doses of i.c.-TMZ (1-10 mg) were administered into the brainstem using AlzetTM pumps in order to evaluate survival rates and neurotoxicity. For tumor implantation, rats received an injection of 10(5) 9 L gliosarcoma cells. For local therapy, 5 days after inoculation, a total amount of 1 mg of TMZ or saline was administered into the brainstem at 1 μl/h over 7 days (n = 8/group). For systemic therapy, rats were treated with an orally administered maximum daily dose of 50 mg/kg TMZ for 5 consecutive days. Survival time and neurological deficit were recorded as outcome parameters. In the neurotoxicity study, low dose TMZ (1 mg) was feasible to be administered into brainstem over 7 days without neurological deficit. Using high dose TMZ (5-10 mg), marked neurotoxic effect was observed. In the brainstem tumor study, survival was significantly prolonged in low dose i.c.-TMZ group compared to control rats (median survival 23.5 versus 29.5 days; p < 0.01). Systemic therapy with maximal oral-TMZ dose resulted in longer survival time compared to low dose i.c.-TMZ group (median survival 33.5 versus 29.5 days; p < 0.01). i.c.-TMZ is feasible and effective against rat brainstem glioblastoma allograft. However, we could not show superior potential of i.c.-TMZ compared to oral-TMZ administration. Modification of TMZ infusion with systemic therapy warrants future investigations.
    Child s Nervous System 03/2012; 28(5):707-13. · 1.54 Impact Factor
  • Article: Adjacent-level range of motion and intradiscal pressure after posterior cervical decompression and fixation: an in vitro human cadaveric model.
    [show abstract] [hide abstract]
    ABSTRACT: This in vitro human cadaveric study measured adjacent-level kinematics after posterior cervical decompression and fixation. Quantify adjacent-level changes in range of motion (ROM) and intradiscal pressure after posterior cervical decompression and fixation. Optimal length of instrumentation after posterior decompression is unclear. Longer posterior cervical fixation constructs may increase the risk of adjacent-segment degeneration. Eight cervicothoracic spines were evaluated intact, with C3-C6 laminectomy, C3-C6 laminectomy + C3-C6 fixation, C3-C6 laminectomy + C3-C7 fixation, C3-C7 laminectomy, C3-C7 laminectomy + C3-C7 fixation, C3-C7 laminectomy + C2-C7 fixation, C3-C7 laminectomy + C3-T2 fixation, and C3-C7 laminectomy + C2-T2 fixation. Testing included intact moments (± 2.0 N·m) in flexion/extension, axial rotation, and lateral bending, with quantification of ROM at C2-C3, C6-C7, and C7-T1 normalized to the intact spine. Intradiscal pressures were also measured at each level. For the C3-C6 laminectomy group, there were no differences in adjacent-level flexion/extension ROM or intradiscal pressure based on construct length, except at C6-C7, where ROM was significantly decreased when fixation was extended to C7 (P < 0.05). After C3-C7 laminectomy and reconstruction, the greatest increase in C2-C3 flexion/extension ROM and intradiscal pressure occurred in the C3-T2 fixation subgroup (ROM: 348% [P < 0.05]; intradiscal pressure: 319 ± 243 psi [pounds per square inch] vs. 65 ± 41 psi intact [P < 0.05]). At C7-T1, the greatest increase in flexion/extension ROM and intradiscal pressure occurred after C2-C7 fixation (ROM: 531% [P < 0.05]; intradiscal pressure: 152 ± 83 psi vs. 21 ± 14 psi intact [P < 0.05]). For C3-C6 laminectomy, instrumentation to C7 significantly decreased flexion/extension ROM and intradiscal pressure at C6-C7 without significantly increasing either measure at C2-C3 or C7-T1 relative to C3-C6 fixation. In the setting of a C3-C7 laminectomy, when instrumenting to either C2 or T2, consideration should be given to including both levels within these constructs.
    Spine 01/2012; 37(13):E778-85. · 2.08 Impact Factor
  • Article: Vein of Galen malformations: epidemiology, clinical presentations, management.
    [show abstract] [hide abstract]
    ABSTRACT: The vein of Galen aneurysmal malformation is a congenital vascular malformation that comprises 30% of the pediatric vascular and 1% of all pediatric congenital anomalies. Treatment is dependent on the timing of presentation and clinical manifestations. With the development of endovascular techniques, treatment paradigms have changed and clinical outcomes have significantly improved. In this article, the developmental embryology, clinical features and pathophysiology, diagnostic workup, and management strategies are reviewed.
    Neurosurgery clinics of North America 01/2012; 23(1):165-77. · 1.73 Impact Factor
  • Article: A computed tomography-based feasibility study of translaminar screw placement in the pediatric thoracic spine.
    [show abstract] [hide abstract]
    ABSTRACT: Translaminar screws (TLSs) were originally described as a safer alternative to pedicle and transarticular screw placement at C-2 in adult patients. More recently, TLSs have been used in both the cervical and thoracic spine of pediatric patients as a primary fixation technique and as a bailout procedure when dysplastic pedicle morphology prohibits safe pedicle screw placement. Although authors have reported the anatomical characteristics of the cervical and thoracic lamina in adults as well as those of the cervical lamina in pediatric patients, no such data exist to guide safe TLS placement in the thoracic spine of the pediatric population. The goal of this study was to report the anatomical feasibility of TLS placement in the thoracic spine of pediatric patients. Fifty-two patients (26 males and 26 females), with an average age of 9.5 ± 4.8 years, were selected by retrospective review of a trauma registry database after institutional review board approval. Study inclusion criteria were an age from 2 to 16 years, standardized axial bone-window CT images of the thoracic spine, and the absence of spinal trauma. For each thoracic lamina the following anatomical features were measured using eFilm Lite software: laminar width (outer cortical and cancellous), laminar height (LH), maximal screw length, and optimal screw trajectory. Patients were stratified by age (an age < 8 versus ≥ 8 years) and sex. Collected data demonstrate the following general trends as one descends the thoracic spine from T-1 to T-12: 1) increasing laminar width to T-4 followed by a steady decrease to T-12, 2) increasing LH, 3) decreasing maximal screw length, and 4) increasing ideal screw trajectory angle. When stratified by age and sex, male patients older than 8 years of age had significantly larger laminae in terms of both width and height and allowed significantly longer screw placement at all thoracic levels compared with their female counterparts. Importantly, it was found that 78% of individual thoracic laminae, regardless of age or sex, could accept a 4.0-mm screw with 1.0 mm of clearance. As expected, when stratifying by age and sex, it was found that older male patients had the highest acceptance rates. Data in the present study provide information regarding optimal TLS length, diameter, and trajectory for each thoracic spinal level in pediatric patients. Importantly, the data collected demonstrate no anatomical limitations within the pediatric thoracic spine to TLS instrumentation, although acceptance rates are lower for younger (< 8 years old) and/or female patients. Lastly, given the anatomical variation found in this study, CT scanning can be useful in the preoperative setting when planning TLS use in the thoracic spine of pediatric patients.
    Journal of Neurosurgery Pediatrics 01/2012; 9(1):27-34. · 1.53 Impact Factor
  • Article: Animal model of intramedullary spinal cord glioma using human glioblastoma multiforme neurospheres.
    [show abstract] [hide abstract]
    ABSTRACT: Advances in the diagnosis and management of patients with spinal cord tumors have been limited because of the rarity of the disease and the limitations of current animal models for spinal cord glioma. The ideal spinal cord tumor model would possess a number of characteristics, including the use of human glioma cells that capture the growth pattern and local invasive nature of their human counterpart. In this study, the authors' goal was to develop a novel spinal cord tumor model using a human neurosphere cell line. Eighteen female athymic rats were randomized into 3 experimental groups. Animals in the first group (6 rats) received a 3-ml intramedullary injection containing DMEM and were used as controls. Animals in the second group (6 rats) received a 3-ml intramedullary injection containing 100,000 glioblastoma multiforme (GBM) neurosphere cells in 3 ml DMEM. Animals in the third group (6 rats) received a 3-ml intramedullary injection containing 9L gliosarcoma cells in 3 ml DMEM. Functional testing of hindlimb strength was assessed using the Basso-Beattie-Bresnahan (BBB) scale. Once the functional BBB score of an animal was less than or equal to 5 (slight movement of 2 joints and extensive movement of the third), euthanasia was performed. Animals in the GBM neurosphere group had a mean survival of 33.3 ± 2.0 days, which was approximately twice as long as animals in the 9L gliosarcoma group (16.3 ± 2.3 days). There was a significant difference between survival of the GBM neurosphere and 9L gliosarcoma groups (p < 0.001). None of the control animals died (p < 0.001 for GBM neurosphere group vs controls and 9L vs controls). Histopathological examination of the rats injected with 9L gliosarcoma revealed that all animals developed highly cellular, well-circumscribed lesions causing compression of the surrounding tissue, with minimal invasion of the surrounding gray and white matter. Histopathological examination of animals injected with GBM neurospheres revealed that all animals developed infiltrative lesions with a high degree of white and gray matter invasion along with areas of necrosis. The authors have established a novel animal model of spinal cord glioma using neurospheres derived from human GBM. When injected into the spinal cords of athymic nude rats, neurospheres gave rise to infiltrative, actively proliferating tumors that were histologically identical to spinal cord glioma in humans. On the basis of their results, the authors conclude that this is a reproducible animal model of high-grade spinal cord glioma based on a human GBM neurosphere line. This model represents an improvement over other models using nonhuman glioma cell lines. Novel therapeutic strategies can be readily evaluated using this model.
    Journal of neurosurgery. Spine 12/2011; 16(3):315-9. · 1.61 Impact Factor
  • Article: Harvey Cushing and "birth hemorrhage": early pediatric neurosurgery at The Johns Hopkins Hospital.
    [show abstract] [hide abstract]
    ABSTRACT: Of Harvey Cushing's many contributions to neurosurgery, one of the least documented is his early surgical intervention in children and his pioneering efforts to establish pediatric neurosurgery as a subspecialty. Between 1896 and 1912 Cushing conducted nearly 200 operations in children at The Johns Hopkins Hospital. A review of his records suggests that the advances he made in neurosurgery were significantly influenced by his experience with children. In this historical article, the authors describe Cushing's treatment of 6 children, in all of whom Cushing established a diagnosis of "birth hemorrhage." By reviewing Cushing's operative indications, techniques, and outcomes, the authors aim to understand the philosophy of his pediatric neurosurgical management and how this informed his development of neurosurgery as a new specialty.
    Journal of Neurosurgery Pediatrics 12/2011; 8(6):647-53. · 1.53 Impact Factor
  • Article: Predictors of surgery-free outcome in adult endoscopic third ventriculostomy.
    [show abstract] [hide abstract]
    ABSTRACT: Endoscopic third ventriculostomy (ETV) is being used increasingly in adults as an alternative to cerebrospinal fluid (CSF) shunting. We analyze patient, radiographic, and operative factors associated with CSF diversion surgery-free outcomes after ETV. One hundred twenty four consecutive adult patients (>18 years) treated with ETV at an academic institution were retrospectively reviewed according to demographic, clinical, operative, radiographic, and follow-up variables. After excluding patients with unclear etiologies or complex previous CSF shunting regimens, there remained 103 patients undergoing ETV for obstructive hydrocephalus, either as initial intervention or in the setting of shunt failure. The primary end point used to assess ETV failure was return to the operating room for CSF diversion. Return of radiographic findings consistent with uncompensated hydrocephalus was considered as a secondary end point. Associations with ETV failure were assessed via Cox proportionate-hazards regression analysis. Clinical improvement was seen in 76 (74%) patients within a median of one month after surgery. Radiographic improvement was seen in 59 (57%) patients within a median of two months after surgery. Fifty-seven (55%) of the patients remained symptom and surgery-free through last follow-up, a median of 5 [2-9] years after ETV. Lasting morbidity and mortality occurred in less than 1%. Multivariate, independent associations with ETV failure included perioperative steroid use, intraoperative image guidance, and time to radiographic improvement. Patients who had image-guided surgery or perioperative steroid treatment were approximately 2.5 times less likely to experience ETV failure. ETV is a safe and effective procedure in adult patients. Perioperative factors, intraoperative image guidance, and steroid treatment may lower ETV failure rates.
    World Neurosurgery 11/2011; 78(3-4):312-7. · 0.68 Impact Factor
  • Article: Primary intramedullary spinal germ cell tumors.
    [show abstract] [hide abstract]
    ABSTRACT: Intramedullary spinal germ cell tumors are rare lesions, with germinomas being the most common variant. To date, there have been 23 reports of primary intramedullary germ cell tumors described in the literature, the vast majority occurring in Japanese patients. We present a case of a nonmetastatic intramedullary germ cell tumor in a 28-year-old Caucasian woman. Characteristics of intramedullary germ cell tumors are summarized, and the current role for surgery and adjuvant radiation and chemotherapy are discussed.
    World Neurosurgery 11/2011; 76(5):478.e1-6. · 0.68 Impact Factor
  • Article: Early Multimodality Treatment of Intracranial Abscesses.
    [show abstract] [hide abstract]
    ABSTRACT: BACKGROUND: The treatment of brain abscesses remains one of the success stories of contemporary neurosurgery; what began as a nearly uniformly fatal disease at the turn of the 20th century has become a largely curable ailment through the use of operative and pharmaceutical intervention. METHODS: Following institutional review board approval, and through the courtesy of the Alan Mason Chesney Archives, the surgical files of the Johns Hopkins Hospital, 1896 to 1912, were reviewed. RESULTS: A total of six patients were operated on for intracranial abscesses. Three patients died during their admission, the remaining three were discharged with a condition listed as "improved" or "well." CONCLUSIONS: Cushing employed a variety of operative drainage techniques for intracranial abscesses and implemented an early antibacterial agent to provide adjuvant treatment in one patient. Although these cases demonstrate a 50% mortality rate, they provide insight into the challenges faced by neurosurgeons treating intracranial abscesses at the turn of the 20th century.
    World Neurosurgery 11/2011; · 0.68 Impact Factor

Institutions

  • 2004–2013
    • Johns Hopkins University
      • Department of Neurosurgery
      Baltimore, MD, USA
  • 2012
    • Thomas Jefferson University
      Philadelphia, PA, USA
  • 2003–2012
    • Johns Hopkins Medicine
      • • Department of Neurosurgery
      • • Division of Pediatric Surgery
      Baltimore, MD, USA
  • 2011
    • University of Aberdeen
      • School of Medicine and Dentistry
      Aberdeen, SCT, United Kingdom
    • Hospital de Cruces
      Bilbao, Basque Country, Spain
  • 2007–2009
    • University of Maryland, Baltimore
      • Department of Neurosurgery
      Baltimore, MD, USA
    • The Children's Hospital of Philadelphia
      Philadelphia, PA, USA
  • 2008
    • Albert Einstein College of Medicine
      New York City, NY, USA
    • Harvard University
      • Harvard-MIT Division of Health Sciences and Technology (HST)
      Cambridge, MA, USA
    • Tufts Medical Center
      • Department of Neurosurgery
      Boston, MA, USA
  • 2005
    • Aurora St. Luke's Medical Center
      Milwaukee, WI, USA
  • 2002–2003
    • Beth Israel Medical Center
      New York City, NY, USA