Faculty Bibliography

Chordoma, a rare, locally aggressive tumor can affect the central skull base, usually centered at the midline. Complete surgical resection remains mainstay of therapy in case of primary as well as recurrent tumors. Owing to their secluded location, surgical resection of skull base chordomas remains a challenge, even though the recent advancement of endoscopic endonasal approaches has had a significant positive impact on the management of these patients. Endoscopic endonasal approaches have been shown to significantly reduce surgical morbidity when compared to traditional open approaches; however, the classical endoscopic transclival midline approach fails to sufficiently expose parts of many skull base chordomas. More recent refinements of the technique, such as the interdural pituitary transposition and posterior clinoidectomy, the transpterygoid plate approach and the transcondylar far medial approach enable the surgeon the increase the resection rate in these patients. This retrospective case series focuses on anatomical aspects in the surgical management of patients with skull base chordomas. We outline the surgical anatomy of contemporary endoscopic approaches to the skull base based intraoperative illustrations as well as pre- and postoperative 3D reconstructed CT and MR images if our patients. This article should help the clinical choose the most appropriate approach and be aware of relevant anatomy as well as potential shortcomings of a given approach.

The use of virtual surgical planning and computer-aided design/computer-aided manufacturing has gained popularity in the surgical correction of craniosynostosis. This study expands the use of virtual surgical planning and computer-aided design/computer-aided manufacturing in cranial vault reconstruction by using these methods to reconstruct the anterior vault using a single endocortically-plated unit constructed from the posterior calvarium. This technique was designed to reduce the risk of undesirable contour deformities that can occur when multiple bone grafts are used to reconstruct the anterior vault and fronto-orbital rim. Six patients were included in this study, all of which had nonsyndromic craniosynostosis. Excellent aesthetic outcomes were obtained in all patients, without complication. Additionally, the placement of a single reconstructive unit constructed from the posterior calvarium was efficient, aesthetically pleasing, and minimized postoperative contour deformities secondary to bone gaps, resorption, and often palpable resorbable plates.

PURPOSE/OBJECTIVE:Though the use of the pedicled nasoseptal flap (NSF), a reconstructive technique used after endoscopic endonasal approaches (EEA) for resection of craniopharyngiomas, has been shown to reduce the occurrence of post-operative cerebrospinal fluid (CSF) leaks in adults, less is known about its use in pediatric populations, specifically in children under the age of 7. The goal of this retrospective cohort study is to determine the viability of the pedicled NSF for pediatric patients. METHODS:Retrospective review of 12 pediatric patients (ages 2-16) undergoing 13 NSF reconstructions after resection of craniopharyngiomas. Radioanatomic analysis of computed tomography (CT) scans was utilized to classify the pneumatization of the sphenoid sinus depending on the thickness of the sphenoid bone margin. Intercarotid distances were measured from magnetic resonance imaging (MRI) scans to assess the feasibility of this reconstruction technique in pediatric patients. RESULTS:At the time of surgery, all patients were noted to have adequate NSF length and width. No post-operative high-flow CSF leaks were found within the group. Lack of pneumatization of the sphenoid sinus and narrow intercarotid distances in the youngest of patients did not lead to negative clinical outcomes. CONCLUSIONS:Based on our results and experience, the pedicled nasoseptal flap is a viable reconstructive option after EEA in the pediatric population, including even the youngest of patients. In these patients, a narrowed window between the intercarotid arteries and the lack of pneumatization of the sphenoid sinus present a challenge that can be overcome by using stereotactic navigation and advanced endoscopic techniques.

PURPOSE/OBJECTIVE:The endoscopic endonasal approach (EEA) is a credible surgical alternative for the resection of sellar and suprasellar lesions such as pituitary adenomas, craniopharyngiomas, and Rathke cleft cysts. However, its application to pediatric patients poses several unique challenges that have not yet been well evaluated. The authors evaluate the safety, efficacy, and outcomes associated with the use of the EEA for treatment of these pathologic entities in pediatric patients. METHODS:Retrospective review of 30 patients between the ages of two and 24 who underwent endoscopic endonasal resection of sellar or suprasellar lesions between January 2010 and December 2015. Endocrinological and ophthalmological outcomes, as well as extent of resection and complications were all evaluated. RESULTS:Gross total resection was achieved in eight of the nine pituitary adenomas, nine of the 12 craniopharyngiomas, and six of the nine Rathke cleft cysts. Of the 30 patients, 22 remained disease free at last follow-up. A total of six patients developed hypopituitarism and five developed diabetes insipidus. Eleven patients experienced improved vision, sixteen experienced no change, and one patient experienced visual worsening. Postoperative cerebrospinal fluid leak was seen in a single case and later resolved, vasospasm/stroke was experienced by 10% of patients, and new obesity was recorded in 10% of patients. There were no perioperative deaths. CONCLUSIONS:Endoscopic endonasal resection is a safe and effective surgical alternative for the management of sellar and suprasellar pathologies in pediatric populations with excellent outcomes, minimal complications, and a low risk of morbidity.

OBJECTIVE The incidence of posttraumatic ventriculomegaly (PTV) and shunt-dependent hydrocephalus after nonaccidental head trauma (NAHT) is unknown. In the present study, the authors assessed the timing of PTV development, the relationship between PTV and decompressive craniectomy (DC), and whether PTV necessitated placement of a permanent shunt. Also, NAHT/PTV cases were categorized into a temporal profile of delay in admission and evaluated for association with outcomes at discharge. METHODS The authors retrospectively reviewed the cases of patients diagnosed with NAHT throughout a 10-year period. Cases in which sequential CT scans had been obtained (n = 28) were evaluated for Evans' index to determine the earliest time ventricular dilation was observed. Discharge outcomes were assessed using the King's Outcome Scale for Childhood Head Injury score. RESULTS Thirty-nine percent (11 of 28) of the patients developed PTV. A low admission Glasgow Coma Scale (GCS) score predicted early PTV presentation (within < 3 days) versus a high GCS score (> 1 week). A majority of PTV/NAHT patients presented with a subdural hematoma (both convexity and interhemispheric) and ischemic stroke, but subarachnoid hemorrhage was significantly associated with PTV/NAHT (p = 0.011). Of 6 patients undergoing a DC for intractable intracranial pressure, 4 (67%) developed PTV (p = 0.0366). These patients tended to present with lower GCS scores and develop ventriculomegaly early. Only 2 patients developed hydrocephalus requiring shunt placement. CONCLUSIONS PTV presents early after NAHT, particularly after a DC has been performed. However, the authors found that only a few PTV/NAHT patients developed shunt-dependent hydrocephalus.

BACKGROUND: Children who sustained non-accidental head trauma (NAHT) are at severe risk for mortality within the first 24 hours after presentation. OBJECTIVE: Extent of delay in seeking medical attention may be related to patient outcome. METHODS: A ten year, single-institution, retrospective review of 48 cases treated at a large tertiary Children's Hospital reported to the New York State Central Registrar by the child protection team was conducted. The perpetrator was identified in 28 cases based on confession or conviction. The medical and legal records allowed for identification of time of injury and the interval between injury and arrival to the hospital; this information was categorized as follows: <6 hours (without delay); 6-12 hours (moderate delay); >12 hours (severe delay). The King's Outcome Scale for Childhood Head Injury (KOSCHI) score was recorded for each case. RESULTS: All children were three years of age or younger (2.1 - 34 months) and predominantly male (68%; 19/28). 61% of patients (17/28) presented with moderate or severe delay in arrival. A low arrival Glasgow Coma Scale (GCS) score (p<0.0001) and extracranial injuries (p<0.0061) correlated with worse clinical patient outcomes. Patients with an arrival GCS score <7 predominantly arrived without delay or with moderate delay. Patients presenting without delay or with severe delay were more likely to have a higher KOSCHI outcome score upon discharge (p<0.0426). Four of the six patients who died presented after moderate delay. CONCLUSION: Patients presenting to medical care 6-12 hours after NAHT (moderate delay) appeared to have worse outcomes than those presenting earlier or later.

The authors describe the case of a child who presented with hydrocephalus and phenotypic features characteristic of a multiple congenital anomalies/mental retardation syndrome. Dysmorphic facies, medial plantar lipomatosis, and developmental delay were observed in this case and are identical to documented findings of Pierpont syndrome diagnosed in 3 boys. This is the fourth case reported to date and is the first documented case of an oncological process- an intraventricular atypical choroid plexus papilloma tumor-found in association with Pierpont syndrome. Syndromes associated with choroid plexus papilloma are reviewed.

Dystonia is characterized by two main pathophysiological abnormalities: 'reduced' excitability of inhibitory systems at many levels of the sensorimotor system, and 'increased' plasticity of neural connections in sensorimotor circuits at a brainstem and spinal level. A surprising finding in two recent papers has been the fact that abnormalities of inhibition similar to those in organic dystonia are also seen in patients who have psychogenic dystonia. To try to determine the critical feature that might separate organic and psychogenic conditions, we investigated cortical plasticity in a group of 10 patients with psychogenic dystonia and compared the results with those obtained in a matched group of 10 patients with organic dystonia and 10 healthy individuals. We confirmed the presence of abnormal motor cortical inhibition (short-interval intracortical inhibition) in both organic and psychogenic groups. However, we found that plasticity (paired associative stimulation) was abnormally high only in the organic group, while there was no difference between the plasticity measured in psychogenic patients and healthy controls. We conclude that abnormal plasticity is a hallmark of organic dystonia; furthermore it is not a consequence of reduced inhibition since the latter is seen in psychogenic patients who have normal plasticity

OBJECT: Medulloblastomas are the most common malignant brain tumors in children. These tumors are highly invasive, and patients harboring these lesions are frequently diagnosed with distant spread. In this study, the authors investigated the role of Rac1, a member of the Rho family of small guanosine triphosphatases, in medulloblastoma invasion. METHODS: Three established medulloblastoma cell lines were used: DAOY, UW-228, and ONS-76. Specific depletion of Rac1 protein was accomplished by transient transfection of small interfering RNA. Cell invasion through extracellular matrix (Matrigel) was quantified using a transwell migration assay. Mitogen activated protein kinase activation was determined using phospho-MAP kinase-specific antibodies, and inhibition of MAP kinase pathways was achieved by specific small molecule inhibitors. Localization of Rac1 and its expression levels were determined by immunohistochemical analysis using a Rac1-specific antibody, and Rac1 activation was qualitatively assessed by Rac1 plasma membrane association. RESULTS: Small interfering RNA-mediated depletion of Rac1 strongly inhibited medulloblastoma cell invasion. Although depletion of Rac1 inhibited the proliferation of UW-228 cells, and of ONS-76 cells to a lesser extent, it stimulated the proliferation of DAOY cells. Depletion of Rac1 also inhibited the activation of the ERK and JNK MAP kinase pathways, and inhibition of either pathway diminished invasion and proliferation. Immunohistochemical analysis demonstrated that the Rac1 protein was overexpressed in all medulloblastoma tumors examined, and indicated that Rac1 was hyperactive in 6 of 25 tumors. CONCLUSIONS: The authors' data show that Rac1 is necessary for the invasive behavior of medulloblastoma cells in vitro, and plays a variable role in medulloblastoma cell proliferation. In addition, these results indicate that Rac1 stimulates medulloblastoma invasion by activating the ERK and JNK pathways. The authors suggest that Rac1 and signaling elements controlled by this guanosine triphosphatase may serve as novel targets for therapeutic intervention in malignant medulloblastomas