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  • Author or Editor: Jonathan A. Forbes x
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Jonathan A. Forbes, Adam S. Reig, Luke D. Tomycz, and Noel Tulipan

Object

Intracranial hypertension resulting from compression of the superior sagittal sinus (SSS) by an overlying depressed calvarial fracture is a rare condition. Primary surgical treatment for the symptomatic patient in this setting traditionally involves elevation of the fracture, which often carries significant associated morbidity.

Methods

The authors report a case involving a 6-year-old boy who suffered a closed, depressed, parietooccipital fracture as the result of an unhelmeted all-terrain vehicle accident. This fracture caused compression and subsequent thrombosis of the SSS, which resulted in CSF malabsorption and progressive intracranial hypertension. Initially headache free following the injury, he had developed severe and unremitting headaches by postinjury Day 7. A CT angiography study of the head obtained at this time exhibited thrombosis of the SSS underlying the depressed calvarial fracture. Subsequent lumbar puncture demonstrated markedly elevated intrathecal pressures. Large volumes of CSF were removed, with temporary improvement in symptoms. After medical management with anticoagulation failed, the decision was made to proceed with image-guided ventriculoperitoneal shunt insertion.

Results

The patient's headaches resolved immediately following the procedure, and anticoagulation therapy was reinstituted. Follow-up images obtained 4 months after the injury demonstrated evidence of resolution of the depressed fracture, with recanalization of the SSS. The anticoagulation therapy was then discontinued. To the authors' knowledge, this report is the first description of ventriculoperitoneal shunt insertion as the primary treatment of this infrequent condition.

Conclusions

This report demonstrates that select patients with this presentation can undergo CSF diversion in lieu of elevation of the depressed skull fracture—a surgical procedure shown to be associated with increased risks when the depressed fracture overlies the posterior SSS. The literature on this topic is reviewed and management of this condition is discussed.

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Scott L. Zuckerman, Gary S. Solomon, Jonathan A. Forbes, Richard F. Haase, Allen K. Sills, and Mark R. Lovell

Object

Several studies have suggested a gender difference in response to sports-related concussion (SRC). The Concussion in Sport group did not include gender as a modifying factor in SRC, concluding that the evidence at that point was equivocal. In the present study the authors endeavored to assess acute neurocognitive and symptom responses to an SRC in equivalent cohorts of male and female soccer players. The authors hypothesized that female athletes would experience greater levels of acute symptoms and neurocognitive impairment than males.

Methods

Baseline symptom and neurocognitive scores were determined in 40 male and 40 female soccer players by using the Immediate Postconcussion Assessment and Cognitive Testing (ImPACT) scale prior to any SRC. After sustaining an SRC, each athlete completed postconcussion ImPACT tests and was carefully matched on a wide array of biopsychosocial variables. Baseline symptom and neurocognitive test scores were compared, and their acute symptoms and neurocognitive responses to concussive injury were assessed.

Results

Specific a priori hypotheses about differences between males and females at baseline and at postconcussion measurements of verbal and visual memory ImPACT scores were evaluated according to simple main effects of the gender variable and according to baseline-to-postconcussion main effect and interaction of 2 × 2 split-plot ANOVA. Neither the interaction nor the main effects nor the simple main effects for either ImPACT variable were found to be statistically significant. Exploratory ANOVAs applied to the remaining ImPACT variables of visualmotor speed, reaction time, impulse control, and symptom total scores revealed only a single statistically significant baseline-to-postconcussion main effect for the symptom total.

Conclusions

The results failed to replicate prior findings of gender-specific baseline neurocognitive differences in verbal and visual memory. The findings also indicated no differential gender-based acute response to concussion (symptoms or neurocognitive scores) among high school soccer players. The implications of these findings for the inclusion of gender as a modifying factor in this tightly matched cohort are addressed. Potential explanations for the null findings are discussed.

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Abbas Amirjamshidi and Meysam Alimohammadi

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Jonathan A. Forbes, Bret C. Mobley, Thomas M. O'Lynnger, Calvin M. Cooper, Mahan Ghiassi, Rimal Hanif, and Matthew M. Pearson

Object

Pediatric cerebellar astrocytomas with pilomyxoid features include classic pilomyxoid astrocytomas (PMAs) and intermediate pilomyxoid tumors (IPTs). Since the original description of PMA in 1999, most reports in the literature have described PMAs arising from the hypothalamic/chiasmatic region. To the authors' knowledge, PMAs arising from the posterior fossa have not been discussed in the neurosurgical literature. Intermediate pilomyxoid tumors, or tumors with pathological features of both pilocytic astrocytoma (PA) and PMA, have only recently been described. In this article, the authors present 2 cases that fall within the spectrum of pediatric cerebellar PMA—including a classic PMA and an intermediate pilomyxoid tumor. The authors compare the radiological presentation, surgical results, and postoperative course to findings in a cohort of 15 patients with cerebellar PAs.

Methods

Between 2003 and 2010, 2 patients with pilomyxoid-spectrum astrocytomas underwent treatment at Vanderbilt Children's Hospital. One was a 22-month-old girl who presented with progressive gait disturbance and falls. The other was a 4-year-old girl who presented with ataxia and generalized weakness. In a retrospective review of pediatric cerebellar neoplasms resected by the senior author during this period, these tumors comprised 4% of cerebellar neoplasms and approximately 10% of cerebellar glial neoplasms.

Results

Both patients were treated with midline suboccipital craniotomy for resection. In both cases, tumor invasion anteriorly into the brainstem prevented gross-total resection. the patient in Case 1 was placed on chemotherapy following pathological diagnosis and later developed definitive evidence of leptomeningeal dissemination (LD) 3 years after the operation. The patient in Case 2 was placed on chemotherapy after exhibiting progressive evidence of local recurrence (findings were negative for LD) 12 months following resection.

Conclusions

Pediatric patients with cerebellar pilomyxoid-spectrum astrocytomas appear to suffer higher rates of local recurrence and LD than pediatric patients with cerebellar PAs.

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Jonathan A. Forbes, Lola B. Chambless, Jason G. Smith, Curtis A. Wushensky, Richard L. Lebow, JoAnn Alvarez, and Matthew M. Pearson

Object

The question of whether to obtain routine or selective preoperative imaging of the neuraxis in pediatric patients with cerebellar neoplasms remains a controversial topic. Staging of the neuraxis is generally considered beneficial in patients with neoplasms associated with an elevated risk of leptomeningeal dissemination (LD). When these studies are obtained preoperatively, there is a decrease in the number of false-positive images related to debris in the immediate postoperative period. Additionally, knowledge of the extent of spread has the potential to affect the risk/benefit analysis of aggressive resection. Although the majority of pediatric neurosurgeons surveyed choose to obtain selective preoperative imaging of the neuraxis in cases of cerebellar neoplasms “with findings suggestive of high-grade pathology,” an evidence-based protocol in the literature is lacking. The goal of this study was to assess radiological characteristics of tumors with an elevated risk of LD and identify a method to help guide preoperative imaging of the neuraxis.

Methods

The authors first reviewed the literature to gain an appreciation of the risk of LD of pediatric cerebellar neoplasms based on underlying histopathology and/or grade. Available evidence indicates preoperative imaging of the neuraxis in patients with Grade I tumors to be of questionable utility. In contrast, evidence suggested that preoperative imaging of the neuraxis in patients with Grades II–IV neoplasms was clinically warranted.

The authors then evaluated an extensive base of neuroradiological literature to identify possible MR imaging and/or CT findings with the potential to differentiate Grade I from higher-grade neoplasms in pediatric patients. They analyzed the preoperative radiological findings in 50 pediatric patients who had undergone craniotomy for resection of cerebellar neoplasms at Vanderbilt Children's Hospital since 2003 with reference to 7 chosen radiological criteria. Logistic regression models were fit using radiological features to determine the best predictors of Grades II–IV tumors. Receiver operating characteristic methods were used to identify diagnostic properties of the best predictors.

Results

The relative T2 signal intensity (RT2SI), an indirect measure of the water content of the solid component of the tumor, was best able to identify neoplasms with an elevated risk of LD. An RT2SI value of 0.71 was selected by the authors as the best operating point on the curve. Of the 31 neoplasms retrospectively designated as hypointense T2-weighted lesions (RT2SI ≤ 0.71), 30 (97%) were Grade II or higher. All medulloblastomas, ependymomas, and high-grade (Grades III and IV) neoplasms were hypointense T2-weighted lesions. Of the 19 T2-weighted hyperintense neoplasms (RT2SI > 0.71), 16 (84%) were Grade I and 3 were Grade II.

Conclusions

Measurement of the RT2SI can help predict Grade II–IV tumors at an elevated risk of leptomeningeal spread and guide staging of the neuraxis. Pediatric patients with cerebellar neoplasms found to have an RT2SI of less than or equal to 0.71 are recommended for neuraxis imaging prior to surgery.