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Marius Maxwell, Dimitris Karacostas, Richard G. Ellenbogen, Amnon Brzezinski, Nicholas T. Zervas and Peter McL. Black

✓ A 6-year-old girl developed secondary sexual characteristics 5 months after severe closed head injury. Endocrinological tests confirmed a pubertal sexual condition; there was also diminution of serum melatonin and disruption of the diurnal pattern. Magnetic resonance imaging demonstrated focal hypothalamic injury; this is believed to be the first time such a posttraumatic lesion has been demonstrated by imaging techniques. The pathophysiology of this condition is discussed.

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Richard G. Ellenbogen, Rocco A. Armonda, Dennis W. W. Shaw and H. Richard Winn

In patients with Chiari I malformation with and without associated syringomyelia, aberrant cerebrospinal fluid (CSF) dynamics and a spectrum of posterior fossa pathological findings are demonstrated. In this study, the authors test the validity of using prospective cardiac-gated phase-contrast cine-mode magnetic resonance (MR) imaging to define the malformation, delineate its pathophysiology, and assist in implementing a rational treatment plan.

Eighty-five cases were prospectively analyzed using cine MR imaging. Sixty-five patients, adults and children, with symptomatic Chiari malformation, with and without syringomyelia, were surgically treated from 1990 to 1999. All patients underwent pre- and postoperative cine MR evaluation. Ten patients were treated after a previous surgical procedure had failed. To establish CSF flow characteristics and normative CSF profiles, 20 healthy volunteers were examined.

Compared with normal volunteers, in Chiari I malformation patients with and without syringomyelia, uniformly abnormal craniocervical junction CSF flow profiles were revealed. After intradural exploration, nearly all patients with Chiari I malformation experienced clinical improvement and CSF flow profiles, paralleling those of normal volunteers, were shown. In all patients in whom treatment had failed, abnormal preoperative CSF flow profiles, which correlated with suspected physiological abnormalities and the pathological findings noted at reoperation, were demonstrated.

Symptomatic Chiari I malformation is a dynamic process characterized by the impaction of the hindbrain in an abnormal posterior fossa. This compression obstructs the normal venting of CSF in and out of the craniocervical sub-arachnoid space, throughout the cardiac cycle. Therefore, decompression or enlargement of the posterior fossa to establish normal CSF pathways should be the primary goal of surgical intervention. Aberrant CSF flow appears to be only one aspect of the pathological condition found in patients with Chiari I malformation. Arachnoid scarring in the posterior fossa and selective vulnerability of the spinal cord may also be factors in the pathogenesis and maintenance of associated syringomyelia. Phase-contrast cine MR imaging is a useful tool in defining physiological and anatomical problems in patients with Chiari I and syringomyelia, and it can help guide an appropriate primary or salvage surgical therapy.

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Richard G. Ellenbogen

Object

Tumors of the lateral ventricle can be removed via two major approaches: the transcallosal or the transcortical route. The purpose of this study is to discuss the techniques and outcomes in transcortical surgery of tumors located in the lateral ventricle.

Methods

An experience with 29 consecutive lateral ventricular tumors resected via the transcortical route, over a 5-year period, is presented. The risks, complications, and outcomes of this surgical series, as well as those reported in the literature, are discussed. Surgical approaches to all five regions of the lateral ventricle are described. Neuropsychological, functional, and neurological outcomes are evaluated.

Conclusions

The transcortical technique makes it possible to resect lesions in each of the five regions of the lateral ventricle. It provides superior microsurgical working space and flexibility for maneuvering within the lateral ventricle. The key to a successful transcortical approach is an understanding of the functional anatomy of eloquent cortex to be broached, the location of the lesion, and its vascular supply. A clear understanding of the advantages and limitations of the transcortical approach makes performing this procedure for resection of large lesions in the ventricle both safe and effective. The majority of the patients in this series (86%) had a good outcome, returning to baseline functional status and suffering minimal morbidity. In the microsurgical era, transcortical surgery–related postoperative morbidity and outcome are dependent more on tumor histological type and site of origin than on approach.

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Ali H. Mesiwala, Christopher I. Shaffrey, Joseph S. Gruss and Richard G. Ellenbogen

✓ The authors present the first known reported case of hemifacial microsomia associated with a Chiari I malformation and syrinx. A 14-year-old girl presented with progressive torticollis of 3 years' duration and headaches exacerbated by exercise. Computerized tomography scanning and magnetic resonance imaging revealed extensive craniofacial and vertebral abnormalities, including aplasia of the floor of the left middle fossa and posterior fossa cranium, articulation of the left mandibular condyle with the left temporal lobe, and progressive development of a Chiari I malformation with associated syringomyelia. The patient first underwent posterior fossa decompression, duraplasty, and occipitocervical fusion. This procedure was later followed by reconstruction of the floor of the left middle fossa and temporomandibular joint. The patient's outcome was excellent. In this case report the authors review the complex embryological development of craniofacial and craniovertebral structures, and emphasize the use of a staged approach to treat pathophysiological consequences of this congenital anomaly.

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Ali H. Mesiwala, John D. Kuratani, Anthony M. Avellino, Theodore S. Roberts, Marcio A. Sotero and Richard G. Ellenbogen

✓ The issue of whether seizures can arise in the cerebellum remains controversial. The authors present the first known case of focal subcortical epilepsy with secondary generalization thought to arise from a dysplastic lesion within the cerebellum. A newborn infant presented with daily episodes of left eye blinking, stereotyped extremity movements, postural arching, and intermittent altered consciousness lasting less than 1 minute. These episodes began on his 1st day of life and progressively increased in frequency to more than 100 events per day. Antiepileptic medications had no effect, and interictal and ictal scalp electroencephalography (EEG) recordings demonstrated bilateral electrical abnormalities. Magnetic resonance imaging revealed a mass in the left cerebellar hemisphere, and ictal and interictal single-photon emission computerized tomography revealed a focal perfusion abnormality in the region of the cerebellar mass. The patient subsequently underwent intraoperative EEG monitoring with cortical scalp electrodes and cerebellar depth electrodes. Intraoperative EEG recordings revealed focal seizure discharges that arose in the region of the cerebellar mass and influenced electrographic activity in both cerebral hemispheres. Resection of this mass and the left cerebellar hemisphere led to complete resolution of the patient's seizures and normalization of the scalp EEG readings. Neuropathological findings in this mass were consistent with ganglioglioma. A review of the literature on the cerebellar origins of epilepsy is included.

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Gerald A. Grant, Matthew Jolley, Richard G. Ellenbogen, Theodore S. Roberts, Joseph R. Gruss and John D. Loeser

Object. The authors have routinely performed primary autologous cranioplasty to repair skull defects after decompressive craniectomy. The high rates of subsequent bone resorption occurring in children prompted this study.

Methods. In an institutional review, the authors identified 40 (32 male and eight female) children and adolescents ranging from 4 months to 19 years of age in whom autologous cranioplasty was performed after decompressive craniectomy. The defect surface area ranged from 14 to 147 cm2. In all cases, the bone was fresh frozen at the time of the decompression. Symptomatic bone resorption subsequently occurred in 20 children (50%) in all of whom reoperation was required. The incidence of bone resorption significantly correlated with an increased skull defect area (p < 0.025). No significant correlation was found with age, sex, or anatomical location of the skull defect, number of fractured bone fragments, presence of a shunt, cause for decompressive craniectomy, method of duraplasty, or interval between the craniectomy and the cranioplasty. Reoperation to repair the resorbed autologous bone was performed 2 to 76 months after the initial procedure.

Conclusions. The use of autologous bone to reconstruct skull defects in pediatric patients after decompressive craniectomy is associated with a high incidence of bone resorption. The use of autologous bone should be reevaluated in light of the high rate of reoperation in this pediatric population.

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Saadi Ghatan, David W. Newell, M. Sean Grady, Sohail K. Mirza, Jens R. Chapman, Frederick A. Mann and Richard G. Ellenbogen

✓ Children younger than 3 years of age represent a distinct subpopulation of patients at particular risk for high cervical and craniovertebral injuries. There are few descriptions of survivors of severe craniocervical trauma among the very young, and scarce data exist regarding management after initial emergency stabilization.

The authors describe three children, age 1 to 32 months, who presented with craniocervical junction injuries. Variable neurological findings were observed at presentation (cranial nerve deficits, obtundation, and moderate-to-severe quadriparesis). All three were treated with prolonged immobilization and have recovered with minimal to no neurological deficit.

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Taylor J. Abel, Abhineet Chowdhary, Patrik Gabikian, Richard G. Ellenbogen and Anthony M. Avellino

✓ The authors report the case of a 3-year-old girl with a Chiari malformation Type I (CM-I) and concomitant fatty terminal filum. This child was examined prior to the onset of CM-I as well as after, and the authors present magnetic resonance (MR) images documenting that the malformation was acquired as the child grew in height. This case contributes to the literature describing an acquired CM-I associated with a fatty filum and is the first published account to include MR imaging obtained before and after the onset of the malformation.

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Samuel R. Browd, Jacob Zauberman, Mahesh Karandikar, Jeffery G. Ojemann, Anthony M. Avellino and Richard G. Ellenbogen

Object

The authors report their experience with a novel flexible fiber capable of transmitting CO2 laser energy during spinal cord tumor resection and detethering.

Methods

A fiber optic system capable of transmitting CO2 laser energy was used in the detethering of the spinal cord in 3 cases. The first case involved a 9-year-old girl with a terminal lipoma. The second case was an 11-month-old boy with a thoracic intramedullary dermoid and dermal sinus tract. The third case involved a 13-year-old girl suffering from a tethered spinal cord subsequent to a previously repaired myelomeningocele.

Results

In all 3 cases, the new fiber CO2 laser technology allowed the surgeon to perform microsurgical dissection while sparing adjacent neurovascular structures without time-consuming setup. The system was easy to implement, more ergonomic than previous technologies, and safe. The CO2 laser provided the ability to cut and coagulate while sparing adjacent tissue because of minimal energy dispersion and ease of use, without the articulating arms involved in the prior generation of lasers.

Conclusions

Using a flexible fiber to conduct CO2 laser energy allows accurate microneurosurgical dissection and renders this instrument a high-precision and ergonomic surgical tool in the setting of spinal cord detethering.

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Rohan Ramakrishna, Jeffrey C. Mai, Tanya Filardi, Samuel R. Browd and Richard G. Ellenbogen

This 18-year-old woman presented with symptoms of right upper-extremity ataxia and imaging evidence of syringomyelia and an acquired Chiari malformation after a previous suboccipital decompression for cerebellar hemorrhage. The patient underwent posterior fossa reexploration to detether any adhesions and release scar tissue in the fourth ventricular outlet. Her symptoms of syringomyelia resolved but she then developed symptoms of lethargy, confusion, and amnesia in addition to ataxia. Repeat neural axis imaging revealed resolution of the syrinx but prominent brainstem hypertrophy. Eventually, the placement of a ventriculoperitoneal shunt resulted in the resolution of both symptoms and brainstem hypertrophy. In the present article, the authors elaborate on this first reported case of a reversible brainstem hypertrophy responsive to CSF shunting.