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John C. Liu, Joseph D. Ciacci and Timothy M. George

✓ Treatment of the Dandy—Walker syndrome has included placement of a ventriculoperitoneal shunt alone or in combination with a posterior fossa cystoperitoneal shunt. Complications in shunting are common and are usually related to malfunction or infection. The authors present a case in which the patient developed headaches and focal cranial nerve deficits following infection caused by a cystoperitoneal shunt. Magnetic resonance imaging showed tethering of the brainstem. A posterior fossa craniotomy with microsurgical untethering and cyst fenestration achieved two goals: improvement of the focal cranial nerve deficits and elimination of the cystoperitoneal shunt.

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Timothy M. George and Lisa H. Fagan

Object. As patients with myelomeningocele age, tethered cord syndrome (TCS) in adults with postrepair myelomeningocele has become more common. The authors have structured an evidence-based review of the literature for the purpose of addressing the following questions. 1) How is the diagnosis made? 2) What is the natural history that occurs in adults with postrepair myelomeningocele and TCS? 3) What are the criteria for operative intervention? 4) What is the functional outcome for patients with postrepair myelomeningocele?

Methods. A computerized search of the National Library of Medicine of the English-language literature published from 1966 to 2003 was performed. Articles pertaining to the clinical aspects and management of postrepair myelomeningocele in adults, TCS in adults resulting from closed defects, and pediatric patients with postrepair myelomeningocele were reviewed.

No Level 1 or 2 data were located; however, the search yielded Level 3 and 4 evidence in the literature in which the clinical syndrome, underlying pathology, and the imaging and electrophysiological evaluation for TCS in adults are discussed.

Conclusions. Analysis of the available data indicates the following. 1) A lower lesion level predisposes patients to symptomatic tethering; moreover, orthopedic and urological deterioration will occur in the majority of these patients. 2) Tethered cord release should be considered for adult patients with postrepair myelomeningocele when clinical symptoms, imaging studies, urodynamics, and somatosensory evoked potentials are consistent with TCS. 3) Prompt, aggressive untethering surgery within 5 years of symptom onset, along with long-term follow up to check for delayed retethering, is recommended. The overall outcome for patients with postrepair myelomeningocele may not be as good as the outcome for adults with closed dysraphism.

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Joseph L. Koen, Roger E. McLendon and Timothy M. George

✓ Intradural spinal teratoma is a rare tumor that can be associated with dysraphic defects. Although the origin of these tumors is traditionally thought to be secondary to primordial germ cells misplaced early in embryogenesis, the pathogenesis of intraspinal teratoma remains unclear. The authors present a series of patients in whom an intradural teratoma arose at the same site as a developmental spinal cord abnormality, including a split cord malformation, myelomeningocele, and lipomyelomeningocele. It is postulated that these lesions were the result of a dysembryogenic mechanism and were not neoplastic.

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Timothy M. George and Lisa H. Fagan

Object

As patients with myelomeningocele age, tethered cord syndrome (TCS) in adults with postrepair myelomeningocele has become more common. The authors have structured an evidence-based review of the literature for the purpose of addressing the following questions. 1) How is the diagnosis made? 2) What is the natural history that occurs in adults with postrepair myelomeningocele and TCS? 3) What are the criteria for operative intervention? 4) What is the functional outcome for patients with postrepair myelomeningocele?

Methods

A computerized search of the National Library of Medicine of the English-language literature published from 1966 to 2003 was performed. Articles pertaining to the clinical aspects and management of postrepair myelomeningocele in adults, TCS in adults resulting from closed defects, and pediatric patients with postrepair myelomeningocele were reviewed.

No Level 1 or 2 data were located; however, the search yielded Level 3 and 4 evidence in the literature in which the clinical syndrome, underlying pathology, and the imaging and electrophysiological evaluation for TCS in adults are discussed.

Conclusions

Analysis of the available data indicates the following. 1) A lower lesion level predisposes patients to symptomatic tethering; moreover, orthopedic and urological deterioration will occur in the majority of these patients. 2) Tethered cord release should be considered for adult patients with postrepair myelomeningocele when clinical symptoms, imaging studies, urodynamics, and somatosensory evoked potentials are consistent with TCS. 3) Prompt, aggressive untethering surgery within 5 years of symptom onset, along with long-term follow up to check for delayed retethering, is recommended. The overall outcome for patients with postrepair myelomeningocele may not be as good as the outcome for adults with closed dysraphism.

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J. Timothy Stuntz, George A. Ojemann and Ellsworth C. Alvord Jr.

✓ In this case an aneurysm of the posterior communicating artery developed 9 years after an infundibular dilatation of this posterior communicating artery, without aneurysm formation, had been radiographically demonstrated. Histological examination, after a fatal subarachnoid hemorrhage from the aneurysm, demonstrated that it arose exactly at the site of narrowing of the funnel-shaped infundibulum.

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Brandon G. Rocque, Timothy M. George, John Kestle and Bermans J. Iskandar

Object

The purpose of this study was to report the results of a survey of the American Society of Pediatric Neurosurgeons (ASPN) on treatment of Chiari malformation Type I (CM-I) with syringomyelia.

Methods

A questionnaire was circulated during the 2006 meeting of the ASPN, in which surgeons were surveyed on their management of patients with CM-I and syringomyelia. The survey consisted of questions about 4 clinical scenarios, common causes of surgical failures, and complications.

Results

There were 72 respondents, representing more than 90% of attendees at the 2006 ASPN meeting and approximately half of the society's members. The majority of respondents (85%) reported that they perform posterior fossa decompression as first-line treatment for CM-I with syringomyelia. Seven percent perform bony decompression alone, 36% open the dura, and 27% shrink the tonsils. Very few respondents indicated that they offer syrinx drainage as first-line therapy (< 3%). Although all respondents reported that they treat symptomatic CM-I/syringomyelia patients surgically, 15% of respondents indicated that they do not operate on asymptomatic patients. Finally, respondents stated that their most common complications are pseudomeningocele and chemical meningitis.

Conclusions

This survey, given to a representative group of experienced North American pediatric neurosurgeons, confirms that posterior fossa decompression is still the preferred treatment modality in children with CM-I and syringomyelia, regardless of symptoms. Although most surgeons open the dura, preferred techniques for decompression vary. In contrast to the results of past surveys, conservative follow-up is now only used by a minority of respondents and only in the asymptomatic patient, and primary syrinx drainage seems to have lost popularity. A multicenter trial of surgical outcomes has been designed based on the information from this survey.

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Timothy H. Lucas II, Guy M. McKhann II and George A. Ojemann

Object. The aim of this investigation was to address three questions in bilingualism research: 1) are multiple languages functionally separated within the bilingual brain; 2) are these languages similarly organized; and 3) does language organization in bilinguals mirror that in monolinguals?

Methods. During awake dominant-hemisphere craniotomy in each of 25 bilingual patients, the authors mapped both languages by using identical object-naming stimuli. Essential sites for primary (L1) and secondary (L2) languages were compared. Sites were photographically recorded and plotted onto an anatomically referenced grid system. Language organization in bilinguals was then compared with that in 117 monolinguals and 11 monolingual children.

Conclusions. The authors found distinct language-specific sites as well as shared sites that support both languages. The L1 and L2 representations were similar in total cortical extent but significantly different in anatomical distribution. The L2-specific sites were located exclusively in the posterior temporal and parietal regions, whereas the L1 and shared sites could be found throughout the mapped regions. Bilinguals possessed seven perisylvian language zones, in which L2 sites were significantly underrepresented when compared with the distribution of language sites in monolinguals. These L2-restricted zones overlapped the primary language areas found in monolingual children, indicating that these zones become dedicated to L1 processing. These findings support three conclusions. First, it is necessary to map both languages in bilinguals because L1 and L2 sites are functionally distinct. Second, differences exist in the organization of L1 and L2 sites, with L2-specific sites located exclusively in the posterior temporal and parietal lobes. Third, language organization comparisons in bilingual and monolingual brains demonstrate the presence of L2-restricted zones, which are dedicated to L1.

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Ciaran J. Powers, Timothy George and Herbert E. Fuchs

✓Ventriculoperitoneal (VP) shunt failure is a common problem encountered by pediatric neurosurgeons. The majority of such failures are due to obstruction of the device. Conditions in which intraabdominal pressure is chronically elevated, such as pregnancy, have been associated with shunt failure. Chronic constipation may also result in abnormally elevated intraabdominal pressure and may be an underrecognized cause of distal VP shunt failure. The authors describe the cases of two children who presented with clinical and imaging evidence of VP shunt failure and who were also severely constipated. Treatment of their constipation resulted in both clinical and imaging-documented resolution of their shunt failure.

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William E. Humphries, Peter M. Grossi, Linda G. Liethe and Timothy M. George

✓The authors describe the case of a 36-year-old woman with bilateral internal jugular vein occlusion, hydrocephalus, and Dandy–Walker variant who presented with myelopathy that was ultimately attributed to ventriculoperitoneal (VP) shunt failure. Computed tomography (CT) angiography of the head and neck revealed epidural venous engorgement within the cervical spine, greater that 50% narrowing of the C2–5 spinal canal, and compression of the cervical spinal cord. After successful shunt revision, postoperative CT angiography revealed decreased venous engorgement as well as decompression of the cervical spinal cord, and the patient’s myelopathy improved. This case represents a fascinating clinical presentation of VP shunt failure, highlighting the physiological importance of the external jugular pathways involved in cerebral venous drainage.

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Capillary hemangioma of the fourth ventricle in an infant

Case report and review of the literature

Isaac O. Karikari, Lee A. Selznick, Thomas J. Cummings and Timothy M. George

✓A 3-month-old boy presented to the pediatric neurosurgery service with central hypotonia. Magnetic resonance images of the brain revealed a homogeneously enhancing dumbbell-shaped mass located in the fourth ventricle and extending into the left cerebellopontine angle (CPA). A suboccipital craniotomy was performed and a gross-total resection of the mass was achieved. Pathological examination of the resected tissue confirmed the diagnosis of capillary hemangioma. To the authors’ knowledge, this is the first reported case of a capillary hemangioma occurring in this location. The authors provide a review of the current literature on intracranial capillary hemangiomas and conclude that, despite the rarity of these lesions, they should be considered in the differential diagnosis of lesions in the fourth ventricle and/or the CPA in children.