Cranial synostosis

Cranial synostosis. So here we first want to show you what the major sutures are. As you can see, here is the metopic suture, there is the coronal one going across, sagittal and the lambdoid, and there’s the anterior fontanelle. So growth occurs at right angles to any suture. So any time you have synostosis where the suture fuses prematurely, you cannot grow orthogonal to it. You will grow tangential. I’ll show you, for instance, how brachycephaly develops. Here’s someone where there is coronal synostosis. Order provigil online online at health care pharmacy. See, the yellow line is thick. So the arrows show the growth that is orthogonal to this line, that is 90 degrees perpendicular, is limited and compensatory growth occurs tangential to the suture. What happens then is the shape of the head assumes that. Is that clear now? So what will happen if you have difficulty with a sagittal suture? You won’t be able to grow this way, you’ll grow that way. You’ll get a long boat-head. So it turns out that’s why we call it scaphocephaly. Boat-head. This is commonly encountered cranial synostosis, 40-50% of all cranial synostosis are sagittal. Coronal is brachycephaly, meaning short-head. Lambdoid will cause flat back, like plagiocephaly. When all the sutures are affected you get oxycephaly. I don’t have a good picture of it. What oxycephaly looks like, it looks like a tower-head. See, you can’t grow this way, you can’t grow this way, so you grow straight up. It’s not a very good-looking sight. You can get cranial synostoses in many congenital syndromes, like Cruzon’s syndrome, Apert’s syndrome, Carpenter syndrome, etc. A lot of these kids, again, you probably don’t see them in your continuity clinic in your program, however if you go to the craniofacial clinic, usually run by head and neck surgery and neurosurgery combined, you will see an amazing number of these things. Here are some examples of brachycephaly, scaphocephaly with elongation.

Vascular malformations. Vein of Galen’s you should know. The important associations you make with vein of Galen’s is, first of all I told you it is not an aneurysm. It’s an AVM. You may get this question, not for neurology. You may get it for Neonatology. It’s very very big in the differential for high output heart failure in the newborn. Auscultation of a cephalic bruit accompanies that. A lot of times that how people know somebody has this. You should know a word or two about berry aneurysms. Usually an adolescent gets into trouble, maybe 17-18-year-old, has the worst headache of their life, with a subarachnoid hemorrhage and severe neurologic morbidity. Then they realize after they do the angiography that they have a berry aneurysm. And these usually occur along the circle of Willis at the base of the head, and there is an association of berry aneurysms with aortic coarctation and polycystic renal disease. You just have to try to remember that type of strange associations.

Tuberous sclerosis occurs in about 1:30,000 births, dominant inheritance but many are spontaneous mutations. So if you see a baby with TS you should examine the skin of the patients family and inquire about seizure history in parents. It is certainly a dominant one but a large number of spontaneous mutations. There are two chromosomes that have been identified. One is tuberous sclerosis complex number 1 on chromosome 9 with the first linkage TSE-2, tuberous sclerosis complex 2 on chromosome 16. Interestingly this gene was cloned first, called tuberin and more recently we know this is due to hamartin. So patients may have a mutation in either one of them and they seem to be tumor suppresser genes so when you have a mutation strange things grow all over in your body. Even though TS is very important in neurology it’s really a multi-system disease.

So the cerebral lesions are what I am going to talk about first. They are cortical tubers, or hamartomas and this is where epilepsy comes from. Epilepsy comes from the cortex, and it’s the tubers that cause that problem. There are subependymal glial nodules that I don’t think are that big a problem, except maybe they will appear on the Board with the radiologic questions. Because they make a big issue about these things sticking into the ventricle, giving it a verrucous irregular appearance. You all remember what I am talking about? Okay, so radiologic identification of those and then they can have giant cell astrocytomas in some of these patients. These are malignant. So here’s what I’m talking about in terms of radiologic. This is just a CT scan. You can see down here, this is the parenchyma of the brain. Here’s the ventricular border. It’s a little fuzzy here but you can see that there are these little intense things sticking into the ventricle. You may see that on the Board. That’s unquestionably tuberous sclerosis. If you saw them on an MRI you won’t see them that well because calcified things don’t have a signal on the MRI but in the MRI you may see hamartomas, such as these. Hamartomas are best seen in T-2 weighted images.

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