How will we know if brain surgery was successful?

First some background info:

Ventricles are voids in the brain filled with Cerebral Spinal Fluid (CSF). When brains develop a bleed, which is common in premature babies, blood gets added to the CSF causing the ventricles to expand and push out on the important bits – this is called Hydrocephalus. There are several possible treatments for hydrocephalus and the least surgical one is doing lumbar punctures (spinal taps) where CSF is pulled out from the spinal column in order to let more drain down out of the brain.

Prior to surgery Barnaby had 5 days of Lumbar punctures but they stopped working (presumably because of blood in the spinal fluid causing it to clot). The next option for very small babies is a subgaleal shunt, This is tube inserted into the vertical that runs out through the skull and drains fluid into a pocket underneath the scalp where it can get reabsorbed into the body.

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Barnaby’s subgaleal shunt is in and the incision site on the top of his scalp is starting to heal nicely. Now what? 

There are a few things that the doctors are looking for but the main diagnostic tool that they have is the head ultrasound: they take pictures of his brain to measure the size of his ventricles.  Ventricle size is measured in millimeters across various dimensions which are then plugged into a formula that gives you a “ventricular index” for the left and right sides. 

Ultrasound is the best measuring tool available but is not perfectly accurate. (MRI is probably better but not by enough that it’s worth putting a little baby through all of that)

Another less accurate diagnostic tool is head circumference. Baby’s sculls are essentially separate plates, not yet joined like an adult skull. As his ventricles expand his head gets bigger.

These observations are further complicated by the fact that Barnaby is growing about an ounce a day and his ventricles will be getting naturally bigger as his brain and head grows. 

The last observational tool in play is looking at his scalp to see if there appears to be extra fluid collecting underneath it. This is imperfect because the fluid also get reabsorbed into his body at a variable rate so it’s hard to know how much to expect to see. Doctors feel his scalp to see if it is appropriately “boggy” (that’s the real medical term for skin that is soft because there is fluid collected underneath it).

The only way we will know if all of this worked is to observe these things over time. If the shunt works until his brain bleed heals then this will be the only intervention needed. If the bleed persists but the shunt gets clotted then we look at the next steps. A subgaleal shunt is sufficient as the only intervention needed in about 50% of premature babies with hydrocephalus, the rest end up needing additional interventions of some sort. 

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As of Friday at his last head ultrasound Barnaby’s ventricular index was stable, meaning that it hadn’t shrunken much since the surgery, nobody seemed concerned about that and they decided to hold testing over the weekend, give the guy time to rest. 

Tomorrow we will have another head ultrasound and have a better idea of the trend. In the meantime his head does seem more boggy today than it was yesterday and his head circumference has not gone up despite some weight gain which are both good things.