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Grace Lam, Vivek Mehta and Gabriel Zada

Object

Spontaneous and medically induced CSF leaks are uncommonly associated with pituitary adenomas. The aim of this study was to further characterize the clinical scenarios most closely associated with this phenomenon.

Methods

A review of the literature was conducted to identify all cases of nonsurgical CSF leaks associated with pituitary adenomas. The authors aimed to identify associated risk factors and management strategies used to treat these tumors and repair the CSF leak site.

Results

Fifty-two patients with spontaneous or medically induced CSF leaks in the setting of a pituitary adenoma were identified from 29 articles published from 1980 through 2011. In 38 patients (73%), CSF rhinorrhea developed following initiation of medical therapy, whereas spontaneous CSF leakage developed as the presenting symptom in 14 patients (27%). The patients' mean age was 42.8 years (range 23–68 years). There were 35 males and 17 females. Forty-two patients (81%) had a prolactinoma, with the remaining patients having the following tumors: nonfunctioning pituitary adenoma (6 patients), growth hormone–secreting adenoma (2 patients), mammosomatotroph cell adenoma (1 patient), and ACTH-secreting adenoma (1 patient). Infrasellar tumor invasion into the paranasal sinuses was specifically reported in 56% of patients. The medical agents associated with CSF leakage were dopamine agonists (97%) and somatostatin analogs (3%). The average time from initialization of medical treatment to onset of rhinorrhea was 3.3 months (range 3 days–17 months). Nonsurgical management was successful in 4 patients, including 1 who had successful resolution with a temporary lumbar drain. Forty-six patients (88%) underwent surgical intervention to treat the CSF leak and/or resect the tumor. In 2 patients, surgery was not performed due to medical contraindications or patient preference.

Conclusions

Nonsurgical development of CSF rhinorrhea may occur in the setting of pituitary adenomas, especially following favorable response of invasive prolactinomas to initiation of dopamine agonist therapy. Additional cases have been reported as the presenting symptom of a pituitary adenoma and are likely to be related to decreased tumor volume due to intrinsic infarction or hemorrhage, ongoing invasion, and/or increases in intracranial pressure. Surgical repair, preferentially via a transsphenoidal approach, is the recommended initial treatment for definitive repair of the CSF leak and achievement of maximal tumor resection.

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Vivek A. Mehta, Chetan Bettegowda and George I. Jallo

Tumoral calcinosis (TC), a calcium hydroxyapatite–based mass, is common in the extremities and hips, but has rarely been reported in the spine, and has never been reported within the spinal cord. It may occur sporadically, in familial form, or as a consequence of disorders that promote soft-tissue calcification. Gross-total resection appears to be curative, but the diagnosis of TC is rarely considered prior to surgery. In this report, the authors describe the management of the first case of intramedullary TC located at the T-5 level in a 20-month-old boy who presented with lower-extremity spasticity. Additionally, salient features of the TC diagnosis, radiological patterns, histological findings, treatment, and outcomes are discussed.

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Vivek Mehta, Murray Hong, Julian Spears and Ivar Mendez

The goal of this study was to investigate the ability of fetal dopaminergic neurons to improve complex sensorimotor behavior.

The authors obtained ventral mesencephalic tissue from 14-day-old rat fetuses. The cells were exposed to glial cell line-derived neurotrophic factor (GDNF) prior to transplantation into rats with unilateral 6-hydroxydopamine lesions of the dopaminergic nigrostriatal pathway. Animals that received 400,000 cells exposed to GDNF demonstrated significant improvement in contralateral forelimb function and showed improvement in rotational behavior faster than animals that received cells not exposed to GDNF. Increasing the number of implanted cells to 800,000 exposed to GDNF did not result in any additional improvement in functional recovery.

As neural grafting procedures in the nervous system evolve and genetically engineered cells or stem cells replace fetal tissue, crucial questions about cell number and trophic regulation will need to be addressed. This study demonstrates that grafting of 400,000 cells exposed to GDNF before transplantation has a beneficial effect in the restoration of complex sensorimotor behavior.

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Jonathan Loree, Vivek Mehta and Ravi Bhargava

In this report, the authors illustrate the potential shortfalls of early postoperative MR imaging following resection of a posterior fossa tumor. The authors present the cases of a 10-month-old boy and a 14-year-old boy with posterior fossa tumors that were surgically resected and monitored immediately postoperatively with MR imaging. The MR imaging study obtained immediately postresection while the children were still anesthetized revealed enhancing elements in both patients, which were suggestive of leptomeningeal metastases. When this signal was followed on subsequent MR images, it was no longer visible. The patients are both recurrence free at the time of this publication. These cases demonstrate that early postoperative MR imaging findings for leptomeningeal metastases may be unreliable after excision of posterior fossa tumors and may have potential implications for intraoperative MR imaging techniques currently under development.

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Vivek Mehta, Joshua Bakhsheshian, Amir H. Dorafshar and Edward S. Ahn

The authors describe the case of a boy with Muenke syndrome, an autosomal dominant disorder associated with craniosynostosis. The family history was significant for syndromic craniosynostosis in the patient’s maternal grandmother, who died in adulthood after a craniofacial reconstruction. The patient, her grandson, underwent craniofacial reconstruction surgery at the age of 9 months and developed upward transtentorial herniation. Imaging findings revealed remote cerebellar hemorrhage after a large quantity of supratentorial CSF was drained during postoperative Day 1. The clinical course was further complicated by cerebral sinus thrombosis, which was diagnosed after a fourth surgical procedure. Upward transtentorial herniation can occur when a significant increase in intracranial pressure in the posterior fossa causes displacement of the central lobule and superior surfaces of the cerebellum upward through the incisura tentorii. This is a rare but well-documented phenomenon that commonly occurs in the setting of an expansive posterior fossa lesion or excessive supratentorial CSF loss. To help clinicians recognize and prevent this rare but potentially fatal complication, the authors review the postulated mechanisms by which this process may occur.

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Vivek Mehta, Murray Hong, Julian Spears and Ivar Mendez

Object. The goal of this study was to investigate the ability of fetal dopaminergic neurons to improve complex sensorimotor behavior.

Methods. The authors obtained ventral mesencephalic tissue from 14-day-old rat fetuses. The cells were exposed to glial cell line—derived neurotrophic factor (GDNF) prior to transplantation into rats with unilateral 6-hydroxydopamine lesions of the dopaminergic nigrostriatal pathway. Animals that received 400,000 cells exposed to GDNF demonstrated significant improvement in contralateral forelimb function and showed improvement in rotational behavior faster than animals that received cells not exposed to GDNF. Increasing the number of implanted cells to 800,000 exposed to GDNF did not result in any additional improvement in functional recovery.

Conclusions. As neural grafting procedures in the nervous system evolve and genetically engineered cells or stem cells replace fetal tissue, crucial questions about cell number and trophic regulation will need to be addressed. This study demonstrates that grafting of 400,000 cells exposed to GDNF before transplantation has a beneficial effect in the restoration of complex sensorimotor behavior.

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Vivek A. Mehta, Olindi Wijesekera, Courtney Pendleton, Alfredo Quiñones-Hinojosa, George I. Jallo and Edward S. Ahn

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.

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Brian Lee, Vivek A. Mehta, Arun P. Amar, Matthew S. Tenser and William J. Mack

Open surgical disconnection has long been the treatment of choice for dural arteriovenous fistulas (dAVFs) of the anterior cranial fossa. However, advanced patient age and the presence of medical comorbidities can substantially increase the risk of craniotomy and favor a less invasive endovascular approach. Optimal positioning within the distal ophthalmic artery, beyond the origin of the central retinal branch, is achievable using current microcatheter technology and embolic materials. Here we present the case of an 88-year-old female with an incidentally discovered dAVF of the anterior cranial fossa. Angiographic cure was achieved with one-stage Onyx embolization.

The video can be found here: http://youtu.be/KVE0fUIECQM.

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Vivek A. Mehta, Chetan Bettegowda, George I. Jallo and Edward S. Ahn

Craniosynostosis, the premature closure of cranial sutures, has been known to exist for centuries, but modern surgical management has only emerged and evolved over the past 100 years. The success of surgery for this condition has been based on the recognition of scientific principles that dictate brain and cranial growth in early infancy and childhood. The evolution of strip craniectomies and suturectomies to extensive calvarial remodeling and endoscopic suturectomies has been driven by a growing understanding of how a prematurely fused cranial suture can affect the growth and shape of the entire skull. In this review, the authors discuss the early descriptions of craniosynostosis, describe the scientific principles upon which surgical intervention was based, and briefly summarize the eras of surgical management and their evolution to present day.

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Jian-Qiang Lu, Samir Patel, Beverly A. Wilson, Jeffrey Pugh and Vivek Mehta

Angiocentric glioma is a recently recognized benign brain tumor with unknown histogenesis. Most of these tumors are mitotically low in activity in accord with their benign clinical course. However, increased mitotic activity has been noted in several cases, one of which had an ultimately fatal outcome. Here, the authors present a tumor showing angiocentric glioma and glioblastoma-like features, with recurrence of the lower-grade component after radiotherapy. A 15-year-old boy presented with a 3-month history of progressive left-sided weakness and headache. Magnetic resonance imaging showed a large heterogeneous mass in the right frontal lobe, with mild post-Gd enhancement. A gross-total resection was obtained. Histopathological examination of the resected tissue revealed a tumor with 2 distinct appearances: 1) a mildly to moderately cellular infiltrating tumor with angiocentric glioma characteristics, and 2) a markedly cellular glioblastoma-like tissue with necrosis and microvascular proliferation. The patient received a course of postoperative radiotherapy to 59.4 Gy in 33 fractions administered over the course of 6.5 weeks, but his tumor recurred 4 months after resection. A second resection was then performed. The recurrent tumor exhibited radiation-induced changes and persistent characteristics of angiocentric glioma, but it had fewer malignant features; the mitotic activity was lower, and there was no necrosis or microvascular proliferation. The findings in this case, along with those in several previously reported cases, suggest that angiocentric gliomas may have a malignant variant or malignant transformation. Angiocentric gliomas with malignant features tend to recur, for which surgical intervention followed by radiotherapy and chemotherapy should be offered as a therapeutic option.