A New Angle on Treating Infant Hydrocephalus
Pediatric neurosurgeons treat hydrocephalus. A lot.
This condition, one of fluid build-up around the brain, is usually treated with a routine set of steps. Our pediatric neurosurgery team, including Dr. Neil Feldstein and Dr. Richard Anderson, recently had an unusual case though, and they solved it in an unusual and effective way. They describe their approach in a paper in the journal Child’s Nervous System to share it with other neurosurgeons.
Here’s how things usually go. To treat hydrocephalus in children, pediatric neurosurgeons often make a very small opening in the blocked fluid chambers of the brain. Using computers to help guide their delicate instruments, they create a new pathway for fluid drainage. This procedure is called an endoscopic third ventriculostomy (ETV).
During the same surgery, they also target the area that produces the fluid. Called the choroid plexus, this area is inside the fluid-filled spaces of the brain. The surgeons’ goal is to cauterize the choroid plexus (render it inactive using controlled heat).
Many children can be cured of their hydrocephalus if they get this procedure and more than 90 percent of a patient’s choroid plexus can be cauterized. But reaching that 90 percent mark can be technically difficult. In one-third to two-thirds of surgeries (exact numbers vary by study), less than 90 percent of the choroid plexus can be rendered inactive. In those cases, the child’s hydrocephalus is not cured.
Why does this happen?
There are a few reasons. To some extent, the outcome may depend on the equipment that’s available. One important instrument in this surgery is a thin, small tool with a camera called an endoscope. Both rigid and flexible endoscopes are useful, but in some facilities, only rigid endoscopes are available. In their paper, these doctors mention that they were able to use both.
More of the operation’s success depends on the skill and experience of the neurosurgeon. Neurosurgeons who have performed this surgery more often tend to have better outcomes, and neurosurgeons who are more experienced with the flexible endoscope have better outcomes with that instrument. Luckily, Drs. Anderson and Feldstein are experienced with both rigid and flexible endoscopes, and they have performed many of these surgeries.
The final factor is nature—that is, whether the patient has the right kind of brain structure. Like other parts of the body, human brains follow a general schematic, while also varying a bit between individuals. (Think of the variations between hands, for example.) Individual variations in anatomy may be small, but in an area as important as the inside of a child’s brain, small variations can have a big impact on the success of the surgery.
Depending on individual variation, there might not be room to safely maneuver even the finest surgical instruments and get a “good look” at everything. Enough of the choroid plexus may not be cauterized, and the hydrocephalus may not be cured.
Normally, the next treatment step is to implant a thin tube called a shunt. The shunt drains away the extra fluid and relieves the hydrocephalus. But, as with all surgery, it also carries risks. However, there is one more way to target the choroid plexus. Drs. Anderson and Feldstein performed surgery using endoscopes from the back of the skull. This angle gives a much better visualization and access to the choroid plexus.
This approach to the choroid plexus had never been used in this situation before. Instead, implanting a shunt has become the generally accepted “next step” when the first surgery fails. But neurosurgeons are well aware of the lifelong concerns of shunting infants and the associated complications of living with a shunt.
“In many cases,” summarize the doctors in their paper, “optimal choroid plexus cauterization will be possible from a frontal approach during a traditional [surgery…] However […] there may be cases where anatomic factors, available equipment or technical experience may preclude the most complete choroid plexus cauterization possible.”
In other words, the usual approach will work for many infants, and it should be tried first. But when that technique doesn’t work, doctors now have another option to consider before moving on to a shunt.
In Blog, Brain Tumor Blog, Neurosurgeons, Pediatric Neurosurgery Blog, Pediatrics Tags: , Dr. Anderson, Dr. Feldstein, hydrocephalus, PHHP, residents, Shunt