Hydrocephalus, literally “water on the brain,” is an abnormal build-up of cerebrospinal fluid in the brain cavities known as ventricles. In infants, it can be congenital (it often accompanies spina bifida, for example), or it can be caused by brain hemorrhage or infection. The usual treatment is surgery to implant a shunt, which drains the excess fluid into the abdomen, relieving pressure on the brain.
But over time, shunts nearly always fail, requiring emergency neurosurgery to repair or replace them. But emergency neurosurgery is not something that’s readily available outside of metropolitan areas. Untreated, hydrocephalus causes progressive brain damage and usually death.
What if a one-time operation could treat hydrocephalus permanently? In today’s New England Journal of Medicine, a randomized trial shows good results with a minimally invasive, relatively inexpensive shunt alternative called endoscopic third ventriculostomy with choroid plexus cauterization (ETV/CPC).
Neurosurgeon Benjamin Warf, MD, of Boston Children’s Hospital pioneered ETV/CPC 17 years ago while serving as a medical missionary in Uganda, where shunt failures often are fatal. The operation has two parts. ETV uses an endoscope to create an opening in the floor of the third ventricle, allowing trapped cerebrospinal fluid to escape. CPC uses an electrical current to burn off some of the fluid-producing tissue. Warf explains hydrocephalus, shunting and ETV/CPC in this video:
ETV/CPC has been used to treat hydrocephalus caused by a variety of conditions. Though technically more difficult than shunt placement, failure rates after the six-month mark have been low.
“There are many advantages to avoiding lifelong dependence on a shunt,” says Warf, senior author of the NEJM study. “But one important unanswered question has been whether ETV/CPC is as good for infant brain development as placing a shunt.”
Cognitive outcomes: shunting versus ETV/CPC
The NIH-funded study involved 100 infants at the CURE Children’s Hospital of Uganda who had hydrocephalus as a result of a neonatal nervous-system infection. Fifty-one were randomized to ETV/CPC, and 49 to shunt placement. All babies were under 6 months old; the average age was 3.25 months.
At 12 months, infants randomized to receive a shunt had lower CSF volumes, as expected. But there was no significant difference between treatment arms in regard to brain volume or cognitive scores. (Cognition was measured by the Bayley Scales of Infant Development, administered by trained evaluators who were unaware of treatment assignment.)
“Others have suggested that shunts are a better treatment in regard to neurologic development or brain growth, but we found this was not the case, despite the fact that shunts cause more of a decrease in the ventricle size,” says Warf.
After one year, treatment had failed in 18 patients randomized to ETV/CPC and 12 patients randomized to shunts. This difference wasn’t statistically significant, however.
“We were surprised, because ETV/CPC is expected to have a higher short-term failure rate, whereas shunts tend to fail more over time,” says Warf. “We expect that there will be no further ETV/CPC failures, which nearly all occur within six months, but that the shunts will continue to fail as we follow this cohort.”
Hydrocephalus without shunts?
Warf, a 2012 MacArthur Foundation fellow, spends much of his time training other surgeons in the ETV/CPC technique. The training will soon be aided by a highly sophisticated, anatomically accurate mannequin developed with the help of special effects artists. Above is a simulated endoscopic view from the trainer.
The study had some limitations: It was performed at a single center with expertise in ETV/CPC; it did not have enough statistical power to rule out small outcome differences aside from cognitive scores; and infants in both groups tended to have lower developmental scores due to the original brain infection.
It was also limited to infants with post-infectious hydrocephalus. However, Warf’s group has shown previously that ETV/CPC can prevent the need for shunting in most infants with other causes of hydrocephalus — including brain hemorrhage from prematurity, spina bifida, aqueduct stenosis, encephalocele and Dandy-Walker malformation.
“We will continue to follow these children, but the results further raise our level of confidence in recommending ETV/CPC as the initial treatment for most infants with hydrocephalus,” Warf says. “In the hands of trained surgeons, the operation provides an opportunity to avoid a lifetime of shunt dependence.”
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Abhaya Kulkarni, MD, PhD, of the Hospital for Sick Children in Toronto, and Steven J. Schiff, MD, PhD of Pennsylvania State University are co-first authors on the paper. Other co-authors were Edith Mbabazi Kabachelor, MD, MSc, John Mugamba, MD and Peter Ssenyonga, MD, of CURE Children’s Hospital of Uganda; Ruth Donnelly, PhD, Jody Levenbach, PhD of the Hospital for Sick Children; and Vishal Monga, PhD, Mallory Peterson, BS, Michael MacDonald, MS and Venkateswararao Cherukuri, M. Tech, of Penn State. The study was funded by the NIH’s Eunice Kennedy Shriver National Institute of Child Health & Human Development and the Fogarty International Center (R21TW009612, R01HD085853).