Data on the growth, regression, and de novo formation of arteriovenous malformations (AVMs) suggest that some of these lesions are not formed and developed only during embryogenesis. Patients with hereditary hemorrhagic telangiectasia (HHT) have a genetic propensity to form AVMs. The authors report on the growth and regression of AVMs in a single patient with HHT. This 26-day-old boy with a family history of HHT1 and a mutation in ENG on chromosome 9 presented with a generalized seizure. Results of computed tomography revealed a left frontoparietal intraparenchymal hemorrhage. Cerebral angiography revealed multiple AVMs. Follow-up angiograms obtained 5 months later showed both growth and regression of the AVMs. A craniotomy was performed for complete resection of the left parietal AVM. Histopathological features of the surgical specimen were examined. Active angiogenesis, as indicated by increased endothelial proliferation, might be a part of the underlying pathophysiology of the growth and regression of AVMs.

Because more than half of the children who underwent detethering were found to have abnormal preoperative UDS results, preoperative urodynamic evaluation should be performed in all cases in which detethering is considered. With regard to voiding function, detethering is relatively safe for children with normal preoperative UDS results. In children with abnormal preoperative UDS results, detethering may lead to improvement or even normalization of voiding, especially if the procedure is performed prior to 1 year of age. Finally, children with anorectal anomalies and a tethered cord may represent a subset of patients who are particularly likely to experience urodynamic improvement after detethering.

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Although cerebral vascular malformations are traditionally considered to be congenital lesions, they often become clinically evident in the 3rd to 4th decades of life, leading to the assumption of a long silent clinical period. Unlike vein of Galen malformations, antenatal diagnosis of cerebral arteriovenous malformations (AVMs) is highly uncommon. Postnatal development of an AVM is an emergent concept supported by more clinical observations. Genetic and biological studies demonstrate that an environmental trigger (“second hit”) in addition to genetic predisposition may be a key in understanding the pathophysiology of AVMs and other cerebral vascular lesions such as cavernous malformations (CMs). The authors describe a 6-year-old boy in whom a giant CM was diagnosed and a de novo AVM was detected 25 months after initial resection of the CM. This case seems to support the second-hit hypothesis.

A 4-year-old girl with PHACES syndrome (posterior fossa brain malformations, hemangiomas, arterial anomalies, cardiac anomalies/coarctation of the aorta, eye abnormalities, and sternal clefting/supraumbilical raphe) developed a cerebellar pilocytic astrocytoma 18 months after resolution of her neck, ear, and thoracic hemangiomas. Because cutaneous hemangiomas may have involuted by the time a patient is diagnosed with a central nervous system neoplasm, it seems possible that in other such patients the association may have gone unrecognized. Cerebellar pilocytic astrocytoma may be a rare manifestation of the posterior fossa malformations of PHACES.

The mechanism of parkinsonian tremor may involve a central oscillator, peripheral feedback to the central nervous system (CNS), or both. The thalamus or the globus pallidus is the most likely site for a central oscillator and would be predicted to generate thalamic tremor-related activity characterized, respectively, by calcium spike-associated bursts and by maximal tremor-related activity in the pallidal relay nucleus of thalamus. Thalamic spike trains demonstrate neither of thesc characteristics. However, cross-correlation, latency, and transfer function analysis indicate that sensory feedback is a critical element in the relationship between thalamic activity and parkinsonian tremor. Therefore, thalamic spike train activity is most consistent with parkinsonian tremor being mediated by peripheral inputs involved in either an unstable reflex loop or sensory modulation of a central oscillator.

ALTHOUGH ADVANCES IN prenatal care and diagnosis have reduced the incidence of spina bifida, repair of neural tube defects remains one of the standard cases encountered by pediatric neurosurgeons. The operative techniques used in closure of these congenital defects have remained essentially unchanged during the past 2 decades; however, the operative nuances for closure often are based on the variability in configuration and size of the open defects, which can present a challenge. Repair of the open spinal dysraphism may require only a simple closure, but extensive dissection and reconstruction of the neural, meningeal, fascial, and epidermal tissues, including the use of specialized vascularized flaps, may be required in some cases. In this article, we briefly describe the preoperative evaluation, decision process, and standard techniques for the repair of myelomeningocele and myeloschisis.

ALTHOUGH ADVANCES IN prenatal care and diagnosis have reduced the incidence of spina bifida, repair of neural tube defects remains one of the standard cases encountered by pediatric neurosurgeons. The operative techniques used in closure of these congenital defects have remained essentially unchanged during the past 2 decades; however, the operative nuances for closure often are based on the variability in configuration and size of the open defects, which can present a challenge. Repair of the open spinal dysraphism may require only a simple closure, but extensive dissection and reconstruction of the neural, meningeal, fascial, and epidermal tissues, including the use of specialized vascularized flaps, may be required in some cases. In this article, we briefly describe the preoperative evaluation, decision process, and standard techniques for the repair of myelomeningocele and myeloschisis.