Taylor J. Abel

Time-Dependent Alterations in Functional and Pharmacological Arteriolar Reactivity After Subarachnoid Hemorrhage

Background and Purpose— Disturbances in cerebral arteriolar function, in addition to large vessel vasospasm, may be responsible for ischemia after subarachnoid hemorrhage. The purpose of this study was to test the hypothesis that subarachnoid hemorrhage alters cerebral microvascular reactivity. Methods— An endovascular filament model was used to induce subarachnoid hemorrhage in halothane-anesthetized male Sprague-Dawley rats. We evaluated pial arteriolar responses to sciatic nerve stimulation, topically applied vasoactive agents (adenosine or sodium nitroprusside), and CO2 inhalation in rats subjected to subarachnoid hemorrhage at 1 to 5 days after insult. Results— In sham-operated rats, sciatic nerve stimulation evoked a 23.5±1.8% increase in arteriolar diameter, which was significantly attenuated to 13.7±0.9%, 12.8±2.5%, and 18.8±2.9% at 24, 48, and 72 hours after subarachnoid hemorrhage, respectively (P<0.05; n≥7). At 96 and 120 hours after subarachnoid hemorrhage, sciatic nerve stimulation-induced dilation recovered to sham levels. Somatosensory-evoked potentials were unaltered by subarachnoid hemorrhage. Pial vasodilatation to adenosine (10 &mgr;mol/L) and sodium nitroprusside (1 &mgr;mol/L) were significantly impaired, by 47% and 41%, respectively, at 48 hours after subarachnoid hemorrhage (P<0.05; n=7). In contrast, CO2 reactivity was unaffected by subarachnoid hemorrhage. Conclusions— Pial arteriolar responses to cortical activation may be decreased in the initial 2 to 3 days after experimental subarachnoid hemorrhage.

Cortical stimulation mapping in a patient with foreign accent syndrome: Case report

Foreign accent syndrome is a rare language output disorder characterized by changes in various speech features leading to a perceived foreign accent. There are few cases reported in the literature. Due to the rarity of this condition, information regarding the functional neuroanatomy of FAS is lacking. We present the case of a 60-year-old woman with a left anterior parietal lobe breast carcinoma metastasis who developed foreign accent syndrome (FAS). This patient presented to the emergency room with right upper extremity weakness, facial weakness, and altered speech. Neurological examination revealed the patients speech to be dysarthric and accented, but otherwise appropriate. Brain magnetic resonance (MR) imaging demonstrated a 3cm x 3cm x 3cm lesion in the left anterior parietal lobe. The patient underwent craniotomy for resection of the mass. Intra-operative cortical stimulation mapping demonstrated the lesion to be confined to somatosensory cortex and gross total resection was performed. There were no new neurological deficits post-operatively. To our knowledge, this is a unique case of FAS due to breast carcinoma metastasis. Additionally, this is the first documented case of electrocortical function stimulation mapping of language and Rolandic cortex in a patient with FAS.

Parahippocampal Corpora Amylacea: Case Report

OBJECTIVECorpora amylacea (CA) normally accumulate within perivascular, subpial, and subependymal astrocytic processes. CA are associated with a number of conditions including normal aging, hippocampal sclerosis associated with temporal lobe epilepsy, multiple sclerosis, Lafora-type progressive myoclonic epilepsy, and adult polyglucosan body disease. Reports of massive localized accumulation of CA in the brain outside of these conditions are rare. CLINICAL PRESENTATIONA 49-year-old woman, with a long-standing history of migraine headaches, presented to her primary care provider for increased headache duration. Brain magnetic resonance imaging (MRI) revealed a left parahippocampal lesion, suggestive of low-grade glioma. INTERVENTIONGiven the MRI suggestive of left parahippocampal glioma, left-sided frontotemporal craniotomy was performed for resection of the lesion. Specimens obtained during the operation revealed focal high-density accumulation of CA with no evidence of neoplasm, ischemia, or hypoxic injury. CONCLUSIONThis case illustrates the possibility that localized high-density CA accumulation can present as an intrinsic lesion on brain MRI. CA should be included in the differential diagnosis for patients presenting with brain MRI suggestive of nonenhancing space-occupying lesions.

Reorganization of large-scale physiology in hand motor cortex following hemispheric stroke

Following perinatal hemispheric injury, the developing brain reorganizes hand motor control interhemispherically, reallocating some lost functional representation and processing capacity to the intact hemisphere.1,2 A curious self-reported observation of mirror movement augmentation3 by a patient of ours led us to measure this reorganization electrophysiologically, and from this, make simple observations about the way the brain remaps itself following hemispheric stroke. ### Case report. A 19-year-old man with epilepsy was implanted with subdural electrocorticographic (ECoG) electrodes that included left frontoparietal cortex in order to identify the focus of seizure initiation. The right-handed patient had left-sided spastic hemiplegic cerebral palsy, following a perinatal hemispheric stroke. In the course of his hospital stay, he described and then demonstrated the mirror movement effect of his condition. He gripped 2 of the physicians fingers with his left hand, and then reported he was squeezing with full strength. He then raised his right hand, and slowly formed a fist and contracted with his right hand. As he contracted with his right hand, the grip strength with his left hand grew immensely. We measured the electrophysiology underlying …

Ventriculoperitoneal shunt malfunction presenting as acute paraparesis in an infant

402 J Neurosurg: Pediatrics / Volume 5 / April 2010 Ventriculoperitoneal (VP) shunt surgery is a common treatment for congenital hydrocephalus. Patients with VP shunt malfunctions typically present with headache, nausea, vomiting, increased head circumference, or altered mental status. Syringomyelia with concomitant paraparesis has been reported as a complication of VP shunt malfunction1–3 but only in the setting of Chiari Type II malformation.4 This 23-month-old girl, with surgical history of myelomeningocele repair on her 1st day of life and VP shunt placement, presented to the emergency department with inability to ambulate. Her mother stated she was able to walk without difficulty until a few days prior to presentation when the child expressed reluctance to bear weight on her lower limbs. The mother specifically denied signs of nausea and vomiting, drowsiness, or headache. Neurological examination at this time was notable for lower-extremity hyperreflexia with clonus and an inability to move both lower limbs spontaneously. Otherwise her neurological status was normal. Head CT scanning revealed ventricular enlargement (Fig. 1A) compared with a previous study (Fig. 1B). Spinal MR imaging revealed a holocord syrinx (Fig. 1C). The patient was taken to the operating room for shunt revision, where her shunt tubing was found to be obstructed proximally. A third ventriculostomy was not considered because the patient had communicating hydrocephalus. In the recovery room following surgery, the patient was able to move her legs spontaneously, without hyperreflexia, and the next day she could ambulate regularly. Six weeks after revision surgery, spinal MR imaging revealed significant reduction in the holocord syrinx (Fig. 1D). This case illustrates that syringomyelia should be included in the differential diagnosis of previously shunt-treated patients presenting with acute paraparesis. Prompt shunt revision is indicated and can result in excellent clinical outcome for these patients. (DOI: 10.3171/2009.10.PEDS09191)

Recurrent Supplementary Motor Area Syndrome Following Repeat Brain Tumor Resection Involving Supplementary Motor Cortex.

BACKGROUND: Supplementary motor area (SMA) syndrome occurs after surgery involving the SMA and is characterized by contralateral hemiparesis with or without speech impairment (dependent on involvement of the dominant SMA), which is transient and characteristically resolves over the course of weeks to months. Recurrent SMA syndrome after repeat craniotomy has not been previously described. OBJECTIVE: To describe the presentation and clinical course of patients who developed recurrent SMA syndrome after redo resection of tumors involving the SMA. METHODS: We performed a retrospective review of 15 patients who underwent repeated resection of low-grade glioma from the superior and middle frontal gyrus. Of these patients, we identified 6 cases of recurrent SMA syndrome. RESULTS: Six patients had a documented SMA syndrome occurring after initial and subsequent resection of tumor in proximity to the SMA. Intraoperative localization of eloquent motor and language cortex was achieved in each patient by using a combination of somatosensory evoked potentials and electrocortical stimulation mapping. Location of tumor and extent of resection was examined with magnetic resonance imaging. CONCLUSION: This series demonstrates that recurrent SMA syndrome occurs in patients undergoing repeat resection of tumors involving the SMA. The presence of recurrent SMA syndrome provides support for reorganization of SMA function to adjacent ipsilateral cortex after resection. Patients with recurrent neoplasms of the SMA should be counseled on the possibility of recurrent SMA syndrome. ABBREVIATIONS: fMRI, functional magnetic resonance imaging SFG, superior frontal gyrus SMA, supplementary motor area

Resolution of Acute Hydrocephalus and Migration of Neurocysticercosis Cyst with External Ventricular Drainage

Neurocysticercosis is endemic in the developing world, but is becoming more common in the US due to immigration. A 24-year-old man presented with acute hydrocephalus and headaches, nausea, and vomiting. Head CT revealed a 3rd ventricular cyst and immunological studies were suggestive of neurocysticercosis. EVD placement resulted in migration of the cyst interiorly and superiorly with return of normal CSF flow by MRI and resolution of symptoms. Review of this condition is important given increasing incidence in the United States.

Ectopic glioneuronal tissue in the middle cranial fossa region

The growth of ectopic glioneuronal tissue in the middle cranial fossa region is an uncommon event, with very few cases reported in the literature. In this paper the authors document 4 cases of ectopic glioneuronal tissue in the middle cranial fossa in children and briefly describe the clinical course and pathology. All of the children presented within the first 6 months of life. Two children presented with facial masses, 1 with airway obstruction, and another with proptosis of the right eye. Each child underwent a customized surgery dependent on the location and characteristics of the harbored lesion. Ectopic glioneuronal masses in the middle cranial fossa are rare and benign congenital tumors, and affected newborns can present with airway obstruction, feeding difficulties, and facial deformity depending on the lesion location. Determining an appropriate surgical approach and strategy is a significant challenge and may involve a multidisciplinary team of craniofacial plastic surgeons, otolaryngologists, and neurosurgeons. Although these lesions share clinical and anatomical similarities, because of their histopathological heterogeneity, it is unlikely that they represent a single pathological entity. The long-term outcome in these children is still unknown and is an area for future study. The pathogenesis of these lesions also remains unknown and may be revealed in future research.

THORACIC SPINAL CORD COMPRESSION BY INTRAMEDULLARY HAMARTOMATOUS TISSUE IN A YOUNG BOY : CASE REPORT

OBJECTIVESpinal cord hamartomas are a rare occurrence characterized by well- differentiated mature elements located in an irregular position in the spinal cord. CLINICAL PRESENTATIONThe authors present the unique case of a 12-year-old boy who originally presented to our center for treatment of a right thalamic astrocytoma. One year after his initial presentation, the child developed progressive bilateral leg weakness with decreased sensation. Spinal magnetic resonance imaging performed at this time revealed an intramedullary spinal cord lesion from T4 to T8, which was later found to be composed of hamartomatous tissue. INTERVENTIONThe patient underwent bilateral T4 to T8 laminectomies with subtotal resection of the hamartomatous lesion, and his symptoms improved postoperatively. CONCLUSIONAlthough typically described in the literature as spinal cord hamartomas because of their histological composition, these rare hamartomatous lesions may be the result of a neurulation defect rather than true hamartomas. In patients presenting with multiple neurological conditions, as in our case, diagnosis may be more complex. For those presenting with neurological signs and symptoms, surgical treatment is essential.

Spontaneous Subdural Fluid Collections following Transection of a Fatty Filum Terminale: Case Report and Review of the Literature

We present the case of a 6-year-old girl who developed bilateral subdural fluid collections following transection of her fatty filum terminale. The patient presented to our emergency department 3 weeks subsequent to surgery, reporting symptoms of headache, nausea, and vomiting. The presence of bilateral subdural fluid collections was confirmed by head computerized tomography. Subdural fluid collections and hematomas have been associated with intracranial hypotension and excessive cerebrospinal fluid leakage; however, there are relatively few cases of subdural fluid collections/hematomas following spine surgery reported in the literature. To our knowledge, this is a unique description of development and resolution of subdural fluid collections following surgical transection of a fatty filum terminale.