We are back home from Silas's clinic appointment up at UCSF, which lasted all day Friday. This homecoming was particularly sweet because we had packed our suitcases, expecting that Silas's doctors would recommend another brain surgery. Thankfully we are home again with a happy baby.
In the first weeks after Silas had his shunt placed (Jan. 15) his stridor (a "honk" or snoring sound he sometimes makes when he inhales) had been gradually improving day by day. When it was still around at his last clinic appointment (Feb. 5) his doctors warned us that it might be a symptom of a bigger problem which could require an additional surgery known as "Chiari decompression" surgery. About two weeks ago, when Silas came down with a cold, his stridor became worse and was particularly acute this past week, which increased our fears that he might require that procedure immediately.
A little background since brain surgery is foreign for most of us:
Usually, as the shunt begins to drain the cerebrospinal fluid (CSF) from the lateral ventricles, the pressure in the brain is reduced, which relieves the compression on the cerebellum that causes stridor. In rare cases, however, the symptoms stay on because the brain malformation that nearly everyone with spina bifida has -- the Chiari Type II Malformation -- becomes "symptomatic."
The Chiari II malformation is caused by the open neural tube defect. As CSF leaks out of the opening in the back while the baby is in the womb, the brain stem is pulled down as it develops, leaving the cerebellum significantly lower than it would be in a typically developing child. This "hindbrain herniation" pinches off the third and fourth ventricles and becomes the cause of hydrocephalus. In some cases (perhaps 15% of kids with spina bifida) the Chiari malformation can become symptomatic because the compression pinches the 9th and 10th cranial nerves, leading to problems with breathing and swallowing that can potentially be fatal.
To treat this problem, neurosurgeons can perform decompression surgery, in which they create more space for the cranial nerves by removing small sections of bone from the base of skull. Today it is only done when absolutely required (i.e. if there is fear a child might stop breathing or lose motor function without it).
Thankfully, Silas's doctors at UCSF want to take things slowly and first try to reduce the pressure in his head by increasing the CSF flow from his shunt. His head ultrasound Friday showed that his ventricles are still fairly large so there is a good chance that his stridor is related to that pressure rather than his Chiari malformation. Silas's shunt valve is programmable, so his doctors can adjust the rate of flow from the brain non-surgically using a powerful magnet. On Friday, his doctors placed a magnetic "key" against his skin outside his shunt and changed its setting to drain more fluid, which should hopefully reduce the pressure further and relieve his stridor. They will now monitor him to see if his ventricles will get smaller and told us that will only want to perform the decompression surgery as a last resort.
Meanwhile, to rule out other problems related to symptomatic Chiari, Silas also had a "modified barium swallow study" in which doctors watched on an x-ray as he drank barium to see if he was having any problem feeding. (We weren't particularly worried about this one since he's 17 lbs at 4 months old.) His results were normal in nearly every category, although he does have a small amount of aspiration when drinking thin liquids, which explains his need to pause sometimes when feeding. This is not a big concern, as nearly all kids with a Chiari malformation have some minor issues with sucking and swallowing, but the doctors recommended a "milk thickener" in the short term. Thankfully, they did not see any sign of big amounts of fluid leaking past his vocal chords into his airway or refluxing out of his nose, signs which frequently accompany symptomatic Chiari malformations.
We also met with a pulmonary specialist who listened to Silas's breathing and ordered a bronchoscopy and a sleep study to be conducted at UCSF in the next couple of weeks to make sure that Silas is getting enough oxygen when he is sleeping and check whether his stridor might be related to a more minor condition like tracheomalacia -- a common disorder in infants that goes away with time (which would be wonderful).
It was a long day, but Silas did amazingly well. We feel so blessed to have such an easy-going kid. He smiles at all of his doctors and always cooperates with his tests. A lot of people at the hospital tell us how cute they think he is. Of course, we agree.
We left Friday evening feeling relieved that no one thought decompression surgery was immediately required. The doctors will monitor him closely and hope that the new setting on his shunt will reduce the pressure and eliminate his stridor. From what we understand now, most children's hospitals these days try to do as much as they can to avoid decompression surgery by manipulating the shunt first and resorting to surgery as a last resort. We are confident that he is in good hands at UCSF and are thankful to know that so many of our friends and family are thinking of him and praying for him every day.
We'll keep everyone posted here as things develop. We will have more studies in the next two weeks. For now, Silas is doing well and is as happy and content as ever. He had a fun time this afternoon swimming in the bathtub with mom. It seems just like a normal Saturday, which is a huge relief.
