As a sequel to our previous descriptions of the pathological changes induced by hydrocephalus in the infantile cerebral cortex, the study presented here has evaluated the effects of surgical decompression on cortical cytology and cytoarchitecture. Hydrocephalus was induced in 14 kittens by the intracisternal injection of kaolin at 4 to 11 days of age. Nine of these hydrocephalic animals received low-pressure ventriculoperitoneal shunts at 9 to 15 days after kaolin injection; these animals were monitored preoperatively and postoperatively by ultrasound and were killed at various postshunt intervals up to 30 days. Five normal or saline-injected animals served as age-matched controls. At the time of shunt placement, the ventricular index confirmed that all recipient animals had attained moderate or severe degrees of ventriculomegaly. Within 3 days after shunt placement, the size of the lateral ventricles had decreased to control levels and was accompanied by rapid and dramatic improvements in behavior and skull ossification. When the animals were killed, gross inspection revealed that about half of the animals exhibited mild to moderate ventriculomegaly, with cortical mantles 50 to 80% their normal thickness. Tissue from frontal (primary motor), parietal (association), and occipital (primary visual) cortical areas was processed for light microscopic analysis. Pyknotic or dark shrunken neurons, which are found typically in hydrocephalic brains, were observed only occasionally in the cortex of shunted animals. Gliosis and mild edema were prevalent, however, in the periventricular white matter. The laminae of the cerebral cortex could be identified in all shunted animals. In those animals with mild residual ventriculomegaly, the entire cortical mantle was somewhat compressed, as evidenced by an increased packing density of neurons. Furthermore, the somata of some neurons were disoriented. Overall, these results indicate that most of the morphological characteristics of the cerebral cortex are preserved after surgical decompression and suggest that ventriculoperitoneal shunts may prevent neuronal damage and/or promote neuronal repair.

Over a period of 34 months from 1987 to 1990 we inserted ventricular catheter reservoirs (VCR) into 20 premature low-birth-weight infants who had developed progressive, symptomatic posthemorrhagic hydrocephalus following grade III or IV intraventricular hemorrhages. The mean estimated gestational age was 27.7 ±5.3 weeks and mean birth weight was 1,041 ±699 g. The ventricular catheter reservoirs were placed on day of life 30.7 ± 29.7 and tapped for a total of 3–34 days at varying frequencies and for varying volumes. Of the 20 patients, 4 died on days of life 25, 76, 88, and 187. There were two reservoir infections, both occurring in infants who eventually died. The 16 survivors have been followed from 2 to 24 months (adjusted age). Four (25%) remain shunt-free and 3 have undergone VCR removal. There have been two shunt infections in the 12 shunted patients; ten shunt revisions have been performed overall. At the time of last follow-up, 14 patients were old enough to undergo neurodevelopmental evaluation. Five patients (36%) were ‘normal’ on gross neurological screening examination, 5 (36%) had ‘mild developmental delay’ and 4 (28%) had ‘significant developmental delay’. We feel these data support the continued use of ventricular catheter reservoirs in the management of posthemorrhagic hydrocephalus and offer hope that some of these patients might remain shunt-free and most will have a normal or mildly delayed neurodevelopmental outcome.

With the availability of better endoscopes, improved lighting and increased instrumentation, the use of ventriculoscopy and ventriculostomy in the management of hydrocephalus is becoming increasingly more common. Neurosurgeons recognized the potential for endoscopic surgery early in this century, but were frustrated in many of their attempts at treatment due to the poor quality of the instruments available. Nevertheless, much progress has been made, and the stage was set for better results with modern instrument design. This paper reviews the history of endoscopes in neurosurgery and ponders the direction these instruments will take us in the near future.

As a sequel to our previous descriptions of the pathological changes induced by hydrocephalus in the infantile cerebral cortex, the study presented here has evaluated the effects of surgical decompression on cortical cytology and cytoarchitecture. Hydrocephalus was induced in 14 kittens by the intracisternal injection of kaolin at 4 to 11 days of age. Nine of these hydrocephalic animals received low-pressure ventriculoperitoneal shunts at 9 to 15 days after kaolin injection; these animals were monitored preoperatively and postoperatively by ultrasound and were killed at various postshunt intervals up to 30 days. Five normal or saline-injected animals served as age-matched controls. At the time of shunt placement, the ventricular index confirmed that all recipient animals had attained moderate or severe degrees of ventriculomegaly. Within 3 days after shunt placement, the size of the lateral ventricles had decreased to control levels and was accompanied by rapid and dramatic improvements in behavior and skull ossification. When the animals were killed, gross inspection revealed that about half of the animals exhibited mild to moderate ventriculomegaly, with cortical mantles 50 to 80% their normal thickness. Tissue from frontal (primary motor), parietal (association), and occipital (primary visual) cortical areas was processed for light microscopic analysis. Pyknotic or dark shrunken neurons, which are found typically in hydrocephalic brains, were observed only occasionally in the cortex of shunted animals. Gliosis and mild edema were prevalent, however, in the periventricular white matter. The laminae of the cerebral cortex could be identified in all shunted animals. In those animals with mild residual ventriculomegaly, the entire cortical mantle was somewhat compressed, as evidenced by an increased packing density of neurons. Furthermore, the somata of some neurons were disoriented. Overall, these results indicate that most of the morphological characteristics of the cerebral cortex are preserved after surgical decompression and suggest that ventriculoperitoneal shunts may prevent neuronal damage and/or promote neuronal repair.