Four days after the CT scan, and a day after we were first told the surgery would happen, we finally got to meet with Madison’s neurosurgeon. This has been a meeting we have been looking forward to since Madison was moved to PSL last week. Whenever we asked a nurse or doctor for any neurological information, including an interpretation of the CT scan, we were told we would have to discuss such things with the neurosurgeon. Finally, we got our chance.
With regards to the CT scan, it turns out that Madison did likely have a Grad IV IVH (bleeding in the brain) that severely damaged the parietal occipital cortex area of her brain. This is a part of the brain that is in the posterior and controls things like vision, language reception and sensory reception. Since the damage is on her left side, the vision issues might result in blindness to her right side or other unilateral impacts. The pressure caused by the increasing fluid has also caused her brain in parts to thin beyond comfortable thresholds so other damage may have occurred. They won’t be able to visualize the compression damage until the pressure is relieved by the surgery. Even then, we won’t know the full extent of the damage until we see how Madison develops. She could still run the gamut of near normal to severely disabled, although near normalcy is on the low end of the probability scale at this point.
They had to delay the surgery due to low sodium levels, which can cause seizures or problems with various organs. The neonatologist says the most likely cause of the low sodium is the immaturity of Madison’s kidneys, a problem they see very commonly in preemies. It should resolve on its own as she gets closer to her original gestational due date. But until those levels come up, the surgery is postponed. Likely the surgery will not happen until Saturday.
Not wanting to wait any more to relieve the pressure, the neurosurgeon manually drained some fluid just to tide her over. He estimated that she has 6-7 times the normal volume of fluid in her brain at the current time. Relieving the pressure involved taking a needle approximately 1.75” in length and inserting it into her skull, through the brain and into a ventricle. I asked the doctor how he new he was in a ventricle since there was no ultrasound guiding him and he said, “we’ll know because fluid will come out.” It seems incredibly primitive, but he took the needle portion off of a syringe and stuck it into Madison’ head. Madison was given some topical numbing cream on her head, so the procedure went largely unnoticed from her perspective. Almost immediately, a slow drip of brownish fluid started to seep out the back end of the needle. Normally the fluid is clear but Madison’s is stained from the bleeding she had earlier. It should clear over time as the fluid is drained and replaced.
The doctor used a small collection tube to try and gather up as much as he could for culture. He had intended to drain 10cc, and he needs to be careful not drain too much too quickly or risk a collapse from the inside of the brain itself. The dripping was very slow, however, and he stopped at 1cc-2cc. He said this was probably due to the fact that he used a very thin needle and the pressure was probably not that high (a good thing).
The next step is the regular surgery to implant a subgaleal shunt. This is a type of shunt that allows the fluid from inside the brain to drain to a pocket under the skin around the head. Fluid in the pocket is then naturally reabsorbed by the body, thus doing what the brain isn’t able to do on its own. This procedure takes 20-30 minutes and is fairly routine (if you happen to be a pediatric neurosurgeon who specializes in treating hydrocephalous). This will be the key procedure for treating Madison’s swelling, and the pressure should start to go down for good after the shunt is implanted.
After that, the next step is to put in a permanent shunt, known formally as a ventriculo-peritoneal shunt. This will replace the subgaleal shunt. The primary difference is that rather than draining fluid into a pocket under the skin, it drains fluid through a long tube down into the abdominal cavity. The tube is run entirely under the skin, so it isn’t noticeable, and they put a coil of tubing in her abdomen that will unwind as she grows. 50% of babies who have this put in never need it worked on again. The shunt itself is regulated by a small series of magnets, so the flow can be reprogrammed with powerful magnets and without further surgery. Since there is that 50% chance that the shunt will fail at some point in her life, we will always need to be on the lookout in case her intracranial pressure is increasing.
Madison’s release from the NICU should be gated by the same timelines as our other kids at this point. Can she eat on her own? Are her pulse and breathing stable? While she make take a little longer to get there, she is hopefully on a regular release path we would expect for a preemie. When it looks like she is within a week of being sent home, they will schedule her for the surgery to implant the permanent shunt. As long as the subgaleal shunt is working, the urgency for a permanent shunt is removed.