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ABSTRACT: Pulsatile arterial compression (AC) of the ventrolateral medulla (VLM) is hypothesized to produce the hypertension in a subset of patients with essential hypertension. In animals, a network of subpial neuronal aggregates in the VLM has been shown to control cardiovascular functions. Although histochemically similar, neurons have been identified in the retro-olivary sulcus (ROS) of the human VLM, but their function is unclear.
The authors recorded cardiovascular responses to electrical stimulation at various locations along the VLM surface, including the ROS, in patients who were undergoing posterior fossa surgery for trigeminal neuralgia. This vasomotor mapping of the medullary surface was performed using a bipolar electrode, with stimulation parameters ranging from 5- to 30-second trains (20-100 Hz), constant current (1.5-5 mA), and 0.1-msec pulse durations. Heart rate (HR) and blood pressure (BP) were recorded continuously from baseline (10 seconds before the stimulus) up to 1 minute poststimulus. In 6 patients, 17 stimulation responses in BP and HR were recorded.
The frequency threshold for any cardiovascular response was 20 Hz; the stimulation intensity threshold ranged from 1.5 to 3 mA. In the first patient, all stimulation responses were significantly different from sham recordings (which consisted of electrodes placed without stimulations). Repeated stimulations in the lower ROS produced similar responses in 3 other patients. Two additional patients had similar responses to single stimulations in the lower ROS. Olive stimulation produced no response (control). Hypotensive and/or bradycardic responses were consistently followed by a reflex hypertensive response. Slight right/left differences were noted. No patient suffered short- or long-term effects from this stimulation.
This stimulation technique for vasomotor mapping of the human VLM was safe and reproducible. Neuronal aggregates near the surface of the human ROS may be important in cardiovascular regulation. This method of vasomotor mapping with measures of responses in sympathetic tone (microneurography) should yield additional data for understanding the neuronal network that controls cardiovascular functions in the human VLM. Further studies in which a concentric bipolar electrode is used to generate this type of vasomotor map should also increase understanding of the pathophysiological mechanisms of neurogenically mediated hypertension, and assist in the design of studies to prove the hypothesis that it is caused by pulsatile AC of the VLM.
Journal of Neurosurgery 04/2012; 117(1):150-5. · 2.96 Impact Factor
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ABSTRACT: We review the development of neurosurgery at the Medical University of South Carolina (MUSC) and the emergence of MUSC as a leading academic neurosurgical center in South Carolina. Historical records from the Waring Historical Library were studied, former and current faculty members were interviewed, and the personal records of Dr Phanor J Perot were examined. Dr Frederick E Kredel was the first to perform cerebral revascularization in stroke patients using omental flaps and the first to culture glioma cells in artificial media. The MUSC Neurosurgery residency program was established in 1964 by its first formally trained neurosurgeon, Julian Youmans, MD. The first graduate of the program, Dr Russell Travis, went on to become the President of the American Association of Neurological Surgeons. In 1968, the longest serving chairman, Dr Perot, joined the department and conducted significant research in spinal cord injury, receiving a continuous, 20-year award from the National Institute of Neurological Disorders and Stroke. A major change in the neurosurgery program occurred in 2004 when Dr Sunil Patel accepted the chairmanship. He integrated neurosurgery, neurology, and basic neuroscience departments into a comprehensive Department of Neurosciences to provide integrated clinical care. This department now ranks second in the country in National Institutes of Health research funding. Recently, the Center for Global Health and Global Neurosurgery was established with a vision of caring for patients beyond national borders. Neurosurgery at MUSC has been influenced by Drs Kredel and Perot and the current leadership is moving forward with a uniquely integrated department with novel areas such as global neurosurgery.
Neurosurgery 02/2011; 69(1):145-52; discussion 152-3. · 2.79 Impact Factor
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ABSTRACT: A 54-year-old Caucasian female presented with a 1 year history of intermittent numbness of the left leg progressing to bilateral, lower extremity sensory loss that advanced to include impaired vibration and proprioception. The subsequent thoracic spine magnetic resonance imaging (MRI) scan revealed a heterogeneous, avidly enhancing, centrally situated spinal cord mass involving T7 through T10 in association with thick linear enhancement of the anterior and posterior cord surfaces extending both superiorly and inferiorly. Both the cervical and lumbar spine MRI demonstrated diffuse leptomeningeal disease as well. A brain MRI revealed focal leptomeningeal enhancement in the left and right sylvian fissures, the suprasellar cistern, and the posterior fossa; a pattern consistent with metastatic disease. The patient underwent a T6-T10 laminectomy for tumor biopsy and debulking. Histology revealed a WHO grade III glioneuronal tumor with rosetted neuropil-like islands. Synaptophysin and neurofilament (NF) positive staining was noted within the neural appearing component, whereas, glial fibrillary acidic protein (GFAP) immunopositivity was evident in the fibrillary astrocytoma component of the tumor. The Ki-67 labeling index was 7%. This tumor pattern, now included in the 2007 World Health Organization (WHO) classification of central nervous system tumours as a pattern variation of anaplastic astrocytoma (Kleihues et al. In: Louis et al. (eds) WHO classification of tumours of the central nervous system, 2007), was first described in a four-case series by Teo et al. in 1999. The majority of subsequently reported cases described them as primary tumors of the cerebrum. Herein, we report a unique example of a spinal glioneuronal tumor with neuropil-like islands with associated leptomeningeal dissemination involving the entire craniospinal axis.
Journal of Neuro-Oncology 12/2010; 104(2):529-33. · 3.21 Impact Factor
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Journal of the South Carolina Medical Association, The 12/2010; 106(7):248-53.
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ABSTRACT: Central nervous system (CNS) lymphoma involving the dura mater is very rare and histologically is usually a subtype of non-Hodgkin's lymphoma (NHL) termed mucosa-associated lymphoid tissue (MALT) lymphoma. We present a case of a 46-year old woman with dural MALT lymphoma that was found to also involve a lacrimal gland, inguinal lymph nodes, and bone marrow. Magnetic resonance imaging of the brain showed an extra-axial enhancing mass approximately 6 cm in maximum diameter along the right frontotemporal convexity. Histopathology of the resected dural mass showed MALT lymphoma expressing CD20, CD52, CD19, and CD38. Molecular studies of the B-cell receptor heavy chain demonstrated monoclonality at the involved sites. The patient was treated with four cycles of fludarabine, mitoxantrone, and rituximab with complete remission. She had recurrence in the subcutaneous tissue of the back at 12 months but has remained free of intracranial disease for 31 months. A review of the literature reveals 57 cases of dural MALT lymphoma. Only 4 had extra-CNS involvement at presentation, and only 3 had local recurrence of the dural tumor. Because of the indolent behavior of this tumor, the intracranial portion can be treated conservatively after resection with or without chemotherapy. Deferral of brain radiation can be considered with close clinical and neuroimaging follow up.
Hematology reports. 01/2010; 2(1):e10.
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ABSTRACT: To describe outcomes associated with high-dose radiotherapy with and without temozolomide for high grade central nervous system (CNS) neoplasms.
Retrospective chart review of 60 patients diagnosed with malignant glioma treated with > or =70 Gy radiotherapy.
Median age at diagnosis was 52 years, and 52 patients had astrocytomas (38 glioblastomas). Median prescribed radiotherapy dose was 78 Gy (range 70-80), and 29 patients received concurrent temozolomide. Eighty-six percent completed the planned course treatment. Three patients experienced RTOG grade 3 acute CNS toxicity; late brain necrosis was suspected in four patients. Overall median survival was 13 months (range 2-83). Within glioblastoma patients, temozolomide provided a statistically significant survival improvement over no chemotherapy (median survival 12.7 vs. 7.5 months; P = 0.0058).
High dose conformal radiotherapy to > or =70 Gy with chemotherapy for high-grade CNS neoplasms appears safe but survival remains suboptimal. Within glioblastoma patients, temozolomide provided statistically significant survival improvement over no chemotherapy.
Journal of Neuro-Oncology 01/2009; 93(3):343-8. · 3.21 Impact Factor
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ABSTRACT: The purpose of the present study was to provide empirical evidence of system-based barriers to psychological services for pediatric brain tumor patients when they are medically indicated.
Insurance claims data covering 263,866 insured lives during the 1996 fiscal year were pooled from a cross-sectional national sample of adults and their families insured by private insurance companies or self-insured firms. Based on inclusion criteria, records for 209 pediatric brain tumor patients aged 18 and under were extracted and analyzed. Claims data including total amount of payments made on behalf of a member, total length of hospital stays, and total number of unique admissions were recorded for all patients, and current procedural terminology (CPT) codes were analyzed to determine frequency of payment for routinely billed psychological procedures. Results were then compared to the frequency of payment for routinely billed psychological procedures for children with other medical conditions.
Results indicate that two of the CPT codes commonly associated with neurocognitive evaluations were reimbursed by these third-party payers for pediatric brain tumor patients during the 1996 fiscal year. Additionally, seven of the CPT codes commonly associated with psychological therapy were also reimbursed.
The present findings provide empirical evidence of system-based obstacles (i.e., lack of third-party reimbursement) for medically indicated psychological services in pediatric brain tumor patients.
Pediatric Neurosurgery 02/2006; 42(4):223-7. · 0.70 Impact Factor
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ABSTRACT: We sought to examine the position of a pericranial flap reconstruction of anterior skull base defects with respect to the original floor of the anterior cranial fossa.
A retrospective chart and radiology review of 17 patients (1993-2001) with pericranial flap reconstruction for anterior skull base defects and 17 controls was performed.
At 6 or more months after surgery, the new positions of the pericranial flaps ranged from 5 mm above to 11.3 mm below the positions of the original cribriform plates. There were no complications related to the pericranial flaps such as hemorrhage, flap loss, or brain herniation except for 2 (11.8%) cerebrospinal fluid leaks, 1 of which required operative correction.
Pericranial flap reconstruction is a reliable method with low morbidity for closure of the most common skull base defect from the craniofacial resection that entails removal-unilateral or bilateral-of the fovea ethmoidalis, cribriform plate, and/or superior septum. This flap creates a watertight seal between the extradural space and the nasal cavity, prevents clinically significant brain herniation, and is associated with a low rate of cerebrospinal fluid leakage even without postoperative lumbar subarachnoid drainage of the cerebrospinal fluid.
Otolaryngology Head and Neck Surgery 01/2003; 127(6):494-500. · 1.72 Impact Factor
