Paediatric Embryology: Forearm Deficencies
Summary
This on-demand teaching session will offer medical professionals an overview of how limb deficiencies originate and how they may be organized and addressed, as well as best practices for medical professionals called to such instances. Participants will also take a deep dive into the nuances of F G F factor signaling and the role of gastrulation, and understand how external factors can affect prenatal formation. Discussion will encompass disorders such as Factrel deformity, amelia, phocomelia, polydactyly, ectrodactyly, and syndactyly.
Learning objectives
Learning Objectives for the Session:
- Identify the role of the intermediate and later mesoderm in limb development.
- Describe the key factors that contribute to limb deficiencies.
- Identify the role of FGF factors in limb development.
- Identify the different types of disorders related to FGF factors.
- Identify the potential variables (age of the father/extrinsic factors) that can contribute to limb deficiencies in fetuses/newborns.
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Computer generated transcript
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The following transcript was generated automatically from the content and has not been checked or corrected manually.
But as I'm going to show you, um it's not just the radius and ulna. Uh that's why I've called it forearm deficiencies. So everybody uh this happened in 2014 in Syria, which is why I got the little picture of Jihadi John there. Um you are kidnapped but your family and friends are not paying your ransom. The kidnappers now want to put a bit of pressure onto your family and they're going to cut off a digit and send it to your family to try and entice that ransom money. Which digit do you offer them? So can you switch your microphones on and just talk? Which digit should you offer? The little finger? Okay. Yeah, that's what I that's not a bad thought. Um You're thinking um pinch grip, you're thinking tripod grip. Therefore you're thinking that little finger is um yeah, might, might entice what, 10,000 lbs out of your family? Who else, who else? What, which finger would you offer? Uh Yes. Penelope. I might, I I'm not sure. I just have a weird feeling about this. That might be completely wrong. I would go. Well, definitely not. The thumb. Is this whole scenario is wrong Penelope. I would, for some reason, I think uh little finger is quite essential for grip strength. I would go for index because the middle finger can be used as an index for pinch. If you remove middle rink, then you can have an issue with it. Like not cleft. Exactly. But it can be kind of, you have a void in between. So we'd go for index. Okay. Um That makes very good sense. Anybody else? Middle finger? Yeah, I find them quite useful and expressive. What? No um why the middle finger uh I guess functionally it's all functions. So if you index you, you need a pinch with A I N and F P L, you need your terminal, terminal little finger for grip strength and then the MCP joints in the ring finger has a lot of range of motion. So that gives you your terminal. Yeah, it does, it does. So also, so the whole scenario is wrong. It, this did happen um in 2014, as I say in Syria to a Western hostage. Um So the reason I'm asking is because we're going to come back to this when we're talking about radio club hand, which is um and other pre actual deformities and um and how we may use what we've got left to enhance function in the child by the way, the accepted answer for most people. And there is no right answer if this ends up in a proper MCQ. I'd be very surprised is actually exactly what Penelope said with her rationalization. The idea that your medial three digits, your mid middle ring and little finger are very, very useful for grip strength and that there's very little at the index finger does that the middle finger couldn't be recruited to do. Um which I found really interesting when we, when I learned about this, right? So next slide, please. So imagine you have passed your exams. The letter comes to tell you that you are now an F R C S auth. Next, the natural thing happens and the two zygotes get together. Um And next slide please. Um the two nuclei fuse the chromosomes now become um 46 chromosomes. Next slide, please. Cells begin to divide. This is called cleavage and we are still in the fallopian tube. We are just hours after that fr seahorse announcement. Next slide, please. So um with the cells are still dividing, we're still whizzing through the fallopian tube. Next slide, please. And um now between 16 and 32 cells, um we're almost almost in the uterus. Now the blastocyst, which is what that we're now are um start is a hollow sphere of cells and um and some cells as the dividing clump together to make that inner cell mass. Next please. And now gas relation is about to begin next slide please. It's about day 12, nearly day 10 to day 12. And you can now see um those three layers forming the ectoderm mesoderm and the endoderm and the notochord is forming. Can you see there? Um I think it's a little picture be um the intermediate mesoderm. There's that when that forms about day 12, it signals to the lateral mesoderm to um um um start making little um pads, little digits, next slide, please. So we've got the endoderm mesoderm and Ectoderm by now. Give us a little click, please. Mike. Lovely. So just as a so there we are the Ectoderm mesoderm and then there's the endoderm. So remember the endoderm forms the lung cells, the thyroid cells and the digestive cells, the mesoderm forms the cardiac muscle cells, skeletal muscle cells, renal cells, red blood cells and smooth muscle cells. Did you notice that I started speaking slower when I got to the mesoderm? Yep. And the Ectoderm skin cells and neurons. Now then guys imagine a disorder, a malfunction of the whole of the mesoderm. The mesoderm at this stage day 12 starts to malfunction, malformed. Um Switch on your microphones. Imagine a condition. Yeah. What condition would that be? Imagine a pathology that you might have some passing familiarity with no judgments here, cardiac skeletal renal red blood cells, smooth muscle cells like those in causing peristalsis in the gut. Is it back to el well done. It certainly is that factrel, vertebral anomalies, anal anomalies, cardiac anomalies, um blood marrow thrombocytopenia, red blood cell anomalies and, and other limb anomalies as well. So, yes, there you go. And you can tell that factrel deformity starts to happen. The backdrop pathology happens now at about day 12 and it sort sort of starts to make sense, doesn't it that these cells have this common origin? Next slide, please? So, um we've got, we if we remember back to what I talked about that intermediate mesoderm signaling to the lateral mesoderm. And um and um these paddles, these little stumps appear from the undifferentiated mesoderm. Got an ectoderm covering fibro glass factor 10 is expressed in that lateral plate mesoderm and in turn induces expression of fibro glass factor eight in the ectoderm F G F factors are absolutely critical to growth incidentally, F G F factors. Some of them start to mutate in male sperm um after the age of about 35. So, um disorders that might relate to F G F factors become more common in fathers of over the age of 35. Just a little word of warning, gentlemen. Okay. So um F G F beads induce extra limb, both arms grow before legs. And that's why there are some disorders that specifically affects the upper limbs and some that affect the lower limbs because the arm growth occurs just a day or two before leg growth. So, if there's any issue, extrinsic factor that affects the mother that affects the environment at that time, you can imagine that the arms can be affected more than the legs. Arms need T B X five gene expression. The tee box gene and legs need T box four. Um So genetic disorders in those two genes can sometimes give you bilateral, for example, vocal femoral deficiency or bilateral arm amelia. It's called when there's missing arms. Next slide, please. So I mentioned that they, the limb paddles have um ectoderm on the outside and Ecziderm on the inside, the ectoderm forms, the apical forms little, tiny little zones of two little zones. The apical ectodermal ridge, this has even different fiberglass factors, uh growth, fibroblast growth factors which control activity of the progress zone. That's the, that's the the longitudinal growth of the limb bud and the zone of polarizing activity. The Z P A, the zone zone of polarizing activity controls for the antropa posterior differentiation. So that's um controlling for the the different uh muscles structures of the limbs where the flex is, the extensor is sit next slide, please. And so this that we're still only just at the fifth week here when we get um um the ape ape collector dermal ridge growing, we start to develop these very rudimentary digits. Next click, please. Um And um you start to get apoptosis um as a result of bone marrow protein signaling from sonic hodge hog genes in the zone, a polarizing activity. So this is between weeks 56 and disruption in this process of apoptosis gives you things gives you sinned activity, syndactyly. Um Next slide, please. So pre and post axial development um this occurs at about between weeks seven and eight. So pretty axial means in front of the axis. And this is a concept that took me a long time to understand that middle, quite mean looking cartoon in the middle of my slide is a sort of a graphic of the limb buds, those limb paddles and there's a line that shows you the axis of those paddles. The pale blue is in front of the axis. So it's preaxial, the darker blue is postaxial at this stage, week seven. Um all those limbs face in the same direction, then they rotate. And um so preaxial for the upper limb means the thumb side and preaxial for the lower limb means the little toe side. Next slide, please. What can go wrong? Have a sort of think about this. What can go wrong and when does it go wrong? So we've got disorders of amelia that the absence of an entire limb. One example of um what can cause? Amelia is very early loss of that fiberglass factors signaling pathway. Even before that, it could be the tee box gene mirror amelia, that's part of the limb. Now, this would occur a little bit later. So that's somewhere later in that FGF signaling pathway. Phocomelia is short, poorly formed limbs with some little nubbins at the end, that's a partial loss can occur due to F G F factor disruption or hawks disruption. And then there are other things like ectrodactyly um um which is a disorder of that apoptosis that I was talking about. Remember BMP Sonic hedgehog polydactyly is um same sort of thing but up regulation. Um and syndactyly, if there's up regulation of the zone of polarizing activity, you can get polydactyly. A duplication of that zone of polarizing activity can mean a complete like duplication of them a limb or a nubbin of a limb, an extra limb, if you like loss of the zona zona polarizing activity means a complete loss of half of that limb and the pipe pre or post axial limb. Next slide, please. So when we're looking at deficiencies, absence of a limb or part of a limb, um it can be useful really to organize your mind when you're looking at a child, but new born with um with a deficiency. And remember the sort of times I've had to see a, a newborn baby sometimes is when I worked as a registrar in a district general hospital, a baby can be born at all times with a limb deficiency. And I don't know why. But the first thing they do sometimes or the second or third thing they do is call the orthopedic registrar on call often um in cases where there's wide panic and distress, particularly if it wasn't spotted in the ultrasound scans. And um and then you lumber up as an S T three or an S T four. And what on earth are we meant to do? You know, I've been in that scenario myself at Chase Farm Center of Excellence in North London. And um and one of the things that I think is helpful for us is just to step back and just think just to pause, look and think is this a terminal deficiency of the limb so that there is nothing beyond it or is it an inter calorie deficiency where there is a partial loss and intermediate loss of a component of the limb with something beyond it. So for example, you can have folk amelia's where there are little nubbins of where you have a forearm missing and on what looks like the stump of the elbow, you can have little nubbins of digits. You can have a hemimelia a rare like an absence of a radius, for example, but you'll have some fingers and some part of the wrist joint. On the other hand, you can have conditions uh complete loss of limb, transverse loss of the limb. That would be an amelia or you can have a hemimelia, a radial dysplasia, which trunk eights at the wrist. So there is no wrist and no um fingers. This is of little this classification system. The France and a regular classification system is of little use in terms of prognosis pathology, working out what went wrong. What, what working out what you can do for somebody. It is just a way of organizing your thoughts next slide please. And then there's another classification, which is a little bit more useful in terms of communicating with each other, which is a, a description of what is absent if you don't mention it in the um when you're using this classification, you presume it's present. So for example, right forearm, complete deficiency of the ulnar would assume that there are the hand is there and the wrist is there. Or if you said right forearm, partial deficiency of the ulnar, complete deficiency of the little finger metatarsals and Fallon, geez, you can picture that child already. Um So I've I prefer this classification. Everybody does. Um but you, you describe what's absent and if it's not in the description, it is there, next slide, please. So here we go. So I'm sorry, gentlemen. Um and ladies, yeah, I'd like you to uh sometimes I'm talking just to the gentleman. That's when I'm talking about sperm anomalies over the age of 35. But when it comes to asking which finger you want to chop off or this sort of question, it is this question is open to everybody, right? So this is um this is a made up scenario, totally made up scenario. You see a newborn baby girl with right arm, Amelia, her parents choose to avoid interaction with the medical profession. I have met people like that by the way. But they now want help with a form for disability living allowance. Your um she's got complete right arm Amelia. When was the first time this congenital upper limb deficiency could have first been potentially spotted the 10 week ultrasound, the 20 week anomaly ultrasound or none of the above. So, microphones off, please. Um There's no judgment here. It's a it's a reasonable question in the sense of would you would when you go for your 10 week ultrasound? Can you spot this? In other words, a complete right arm Amelia or does it occur later? So you spot it in the 20 week anomaly ultrasound or can it occur even after that? What do you reckon? I think it would have happened before the 10 week ultrasound, but I don't know what they can see on the ultrasound scan. I think that's a really good point actually. Um Yeah, so um 80% of limb deficiencies are seen on ultrasound. I'm not going to say which ultrasound by the way. Um Because otherwise I'll give the answer, but 20% are not. So um um so 20% of the time, even with very significant lymph deficiencies, um It's total shock to the family when the baby is born, they're expecting a normal baby with all four limbs. They've kept the uptown pictures, you know, it's um as we all do and um and it's uh and that, that um and I've been in that scenario more than once is a real, um shock and um for the family when, when, when this baby arrives. So, um, yeah, 20% of the time you don't see it, there's a limitation to what an ultrasound gives us. So, so 10 week ultrasound, Mike reckons who, who else would like to talk about that? I would agree with Michael. However, I think that there's a reason it's called 20 week anomaly ultrasound. So maybe I will go for that. Uh It's a complete Amelia. We said it's the 4th, 5th week that the limb bad appears. So what? But we, but as we said, because of uh limitations of the scan. So that's so that's the limitations of the scan is whether none of the above is possible. But I really, really love your rationale. You're absolutely right that what goes wrong should be before the 10 week scan. But are there any conditions that occur that can cause complete loss of the limb that occur between the 10 and 20 week scan? So, you have the congenital bands? I don't know. What are they called? Yeah, absolutely. Right. Absolutely. Right. Gentlemen. Uh, if there are any other ladies present, I think Vicky Stoner was there as well. You could do a lot worse than listen to Penelope. She's been on the money so far. Absolutely right. Congenital band syndrome, amniotic band syndrome, amniotic cord syndrome, street is dysplasia. They're all names for the same thing. Um They can all occur I'm just about to shout at this cat. Oh, now I'm coming. This cat moved into our house three months ago and it's just gone on to the work touch, kitchen work tops, which is actually strictly for boating. Um But um it doesn't respond to human command. It responds to human show of strength. So street is this place here between 10 and 12 weeks is or between 10, 13 weeks is thought to occur. Um That's um um amniotic band syndrome. And that is the scenario where you have a normal embryo, normal embryo, normal limb buds, everything is normal. And then this extrinsic band um cuts off the blood supply to that limb and the limb um amputate. It's within the, within the uterus. That's that is a scenario that could happen. Okay. Let's move on to the next slide. Um So uh in this talk, I'm going to talk a little bit about club hand that's essentially radial and ulnar dysplasias, phocomelia, an amniotic band syndrome. Let's move on. So let's talk about radio club hand. So radio club hand, a better name is actually radial dysplasia. It's the most common limit efficiency. It occurs in one in 50,000 to 100,000 people depending on the study. But there must be some sort of genetic association with this condition because it occurs in one in 5000 to finish people. Um There's an absence or partial absence of the pre actual border of the forearm and the ulnar has grows but it has growth retardation and a variable amount of distal deformity. So it tends to curve there is almost always thumb hyperplasia of some sort and stiffness is seen in the fingers to some degree. So in this particular case, is, is quite severe, you can see that the thumb do for um hyperplasia is very, very marked indeed. Um And you can see by the lack of creases, it's not just my blurry group Google um um copy image here. Um If when you see those lack of creases at the falun geez, it tells you that the finger hasn't been flexing and extending in neutro and elbow and wrist range of movement is absolutely critical here. Next slide, please. So, um there's something called the bane classification. You don't need to know these classes. Uh Do you know what I'm going to stop saying this? I, I know I've said this before many times and some people get very, very offended when I say it. Um um um something from what I'm hearing from. Um my, the people I work with over the last few years is that some people um um some people seem to be asked questions and greater depth than others. I don't know if it's um and in my experience, it's people who have a non UK trainees seem to get asked questions in great depth. And so when I say you don't need to know this I don't know what you don't need to know because I was quite, I've been quite shocked recently by what some of my trainees. Um like some of my colleagues have told me when they're asked questions. So what I want you to understand is the principles of this classification. It has a bearing on management. The bane classification refers to the amount of radius that is absent in type one, the radius is present in particular, more pertinently but both approximal and the distal Fyssas is present, but the radius is notably shorter than the ulnar in the X ray image I've I've used here, you can imagine that this is not a very strong deformity clinically, however, there is radial deviation at the carpus which you expect. So, in general, if you've got an upper limb hemimelia that the the hand and the wrist curves towards the missing foot bone. So, so um um so here, the radius is um dysplastic and the hand, the wrist is curving towards the radial side. I think you can see on that X ray. That's really, we've only got, we've, we've got a really a little bit of proximal phalanx of the thumb there. So there is some Hipaa plays Asia. But actually, in terms of the radio club hand, it is not as dramatic as that clinical photograph I showed you a moment ago in type two. Um there is a hypoplastic radius, it is both thinner and shorter. Um but there are proximal and distal growth plates, but you can see how the ulnar is curving. So it's not just that the ulnar is short, the ulnar is also curving. So you have a very shortened forearm in type three, you've just got a small proximal rages. So there is a significant curvature of the ulnar. Um and um and a significant shortening with the radius, almost sort of at the level of the elbow. That's right the hand almost at the level of the elbow. Apologies. I'm in hand in type four, there's a complete absence of the radius. Um and the hand really is looking up in towards the axilla. If you look at that little small little diagram, this little X ray on of type three, um You can see that the elbow is dislocated as well that happens sometimes and that has implications for the prognosis of this child. Next slide please. The treatment options, well, that there are as always whenever you hit hear the word treatment options, you should think surgical and nonsurgical. But the surgical options are to really to line the third metacarpal with the ulnar or two line, the second metacarpal with the ulnar. These are either centralization that's aligning the third metacarpal with the ulnar or radial ization lining the second metacarpal with the ulnar. There is little functional different between either centralization or radial ization. The the knack of what to do is about how much function you have. So next slide please. Next slide please. And next live please. And remember doing nothing is an absolute option. Doing nothing is not literally doing nothing. Um That's not a discharge. You have to think carefully about what the function of that child is. We need our hands. Um By the age of six months, babies are moving their hands to the midline and can usually clap their hands together or pass an object between one hand and another. By the age of six months, by the age of six months, babies are put, moving their hands to, to their mouth for purposefully to put things in their mouth. If the child is doing that at the age of six months, regardless of what the appearance of the high arm looks like. Doing nothing is a very real option. In fact, centralization, radial ization is going to add very little to their function. Next slide please. And this is the point I wanted to make click please. Before you do anything, click. Next slide, you consider associated conditions. So before we get to orthopedic, we must remember that two thirds of Children with radial dysplasia will have an associated condition. So Mike very smartly thought about the mesoderm. Remember that he knows a condition called factual and realized that that is a mesoderm allows pathology that um where vertebra defect, anal atresia, cardiac defeat defect, tracheoesophageal fistula renal abnormalities and limb abnormalities appear far to syndrome. It's just a slightly milder form of factrel. Um And I would suggest that far to syndrome, you just haven't found the cardiac defect yet halt or um syndrome is sometimes called heart hand syndrome where primarily you have a cardiopulmonary and radial defect. So it doesn't affect. In other words, all the museum animal cell lineage tar syndrome is thrombocytopenia with an absent radius fanconi A D anemia is very um serious. It's a a um a pancytopenia and can cause very um and Children can die with a plastic anemia before they're properly diagnosed. You know, everywhere when them, depending on where you are, if, if people focus too much on, on the, on the radius and I haven't really thought about um what else could be going on before, you know, it, the child is severely ill with a plastic anemia and then there are non genetic causes. Um And that's really those poor mothers who are having to take anti epileptics during pregnancy or they didn't know too that they were pregnant. Um So remember these deformities that occur within the first few days of pregnancy, the first few weeks of pregnancy. And um you may not necessarily know that you're pregnant and you're still taking valproate or for, you know, Barbato, mainly, mainly valproate these days. And um and these are some of the deformities that can result next slide, please. So please respond. Which one of the following would be an appropriate test if you're at chase farm sent hospital somewhere like that and a baby is born with radial dysplasia. Everybody's focus is on the very obvious and mark deformity but you as the prime orthopedic registrar, the clever or cleverest doctor in the place. And actually, statistically, we often are, you know, um the the selection process to get into trauma and orthopedics is becoming so stringent that uh you know, there's the old adage of the orthopods being like rugby playing apes just isn't valid anymore. Um So um you need to be thinking about associated and not um features. Remember two thirds of babies with radial displays, you have another condition. So which one of these do you think you should uh order a full blood count? Renal ultrasound, Doppler studies to kidneys, echoes or everything? Okay. Everything. Yeah. Go for it. It's not our money. Yeah, let's do it. Do we need to stop the studies to kidneys though? And if you add anything more than just the renal ultrasound, um it, it, it does if you're, if you're a renal physician, uh but um um the end um the endodermal cell lineages not affected. So the renal blood vessels are not affected. So it's the kidneys that are affected. So, no, just a renal ultrasound, we'll be fine. But yes, it's only money. Doppler studies. The kidneys, why not? But, but actually echo renal ultrasound. And most importantly, the full blood count are really what's needed. Um, Children with fanconi anemia um Tar syndrome, they could have a bone marrow transplant these days. They can get granulocyte um um colony stimulating factor. But they, then the diagnosis has to be made pretty promptly sometimes for to, to get the full advantage of these um treatments. And if we focus too much on the absent radius, um we could be denying this child um life saving treatment. And sometimes we're not, you know, let's face it. We're not going to be the ones necessarily even ordering renal ultrasound or making sense of a blood film in a neonate. Sometimes it just takes a little prompt a little note in the notes. Next slide, please. So the treatment principles actually with all upper limb deformities and deficiencies initially observe there is, um, there is, it's hard to do sometimes because we're goal orientated and patient's have very goal, a goal orientated expectations. But actually, sometimes you just have to observe and, and abs on more than one occasion, what the child is doing and what the child is capable of, particularly in a baby as they, as they hit those three months milestones. Those six months milestones, can they move their hands to their mouth? Can they move their hands to the midline therapy? And splinted is extremely important. But actually the role of splinted and stretching is controversial. The, the reason that ulnar bows like that, the reason that, um, um, there are such tight preaxial structures is thought to be because of some a fibro cartilaginous and lager, which is little to be gained by stretching. It nevertheless, we stretch. The goal is to obtain stable joints, particularly the wrist joint. If you've already got a stable joint, then actually surgery, however, cosmetically more better, it would might be to have a wrist that's not deviated but is central. Um, functionally, it may not add very much, having a longer forearm is useful. So, um, straightening that ulna bow um lengthening the ulnar is uh it could be a very crucial part of surgery. But remember if they cannot get their hand to their mouth easily because they've got, for example, an extension deformity of the elbow. Then if you centralize that hand or radial eyes, that's an ulnar radial is the ulnar. You could stop them getting any movement towards their mouth completely in those Children. A radial deviation of that hand is functionally more useful. Next slide, please. So, um um just some very basic surgical principles. This is a biloba bid um um tissue transfer at the distally. But to be honest, if you look at the slide at the top there, this isn't the most marked of deformities to begin with. They've already had a webspace lengthening. Can you see that if you look at the thumb there? Um beforehand and what they're doing now is centralizing the readily deviated hand because they have more um because this is um because there is more of the carpus here that there are the the hand, the fingers are more functional, they're centralizing the hand. But um centralization and radial ization have similar long term outcomes. The alma is going to be lengthened. Um that if there is significant some hyperplasia, you may need polys ization with the index finger. But you're assuming that those um F P L E P L um those tendons and muscles are working and a functional pre operative assessment on more than one occasion is absolutely mandatory. Next slide, please, complications really are recurrence, pinsight infection and I'm putting this here disappointment. Um Functionally, these Children tend to do well. But the grief that parents suffer when their child is born with such a very marked upper limb deformity can be very difficult to manage and it is helpful to work in a multidisciplinary team. It's helpful to have access. Um um So, so the parents can access the services with these. It's also helpful to facilitate access to support groups and um community of other Children who've had this, other families have had and are living with this condition. Um And that sort of facilitation sometimes requires a more specialist team than we can offer in isolations. Next slide, please. Very quickly, I'm going to talk about ulnar deficiency. Um um This is far rarer, very rare indeed. Um um It's associated with conditions like Cornelia de Lange syndrome, Sh Insel syndrome. And um this condition called ulna fibula dysplasia. They is ulna really good. Actually, apparently there are four families in the world that have that. And um and the individuals who have this condition are related to those four families I read, um which I sort of found quite sort of slightly interesting. So this is a post actual perform itty and remember the hand will deviate towards the absence. So is it the hand deviates towards the ulnar cornelia de Lange is a condition that you do see from time to times. It's a myriad of conditions. Um It's um it's a genetic disorder. It affect short stature, it gives intellectual disability, cleft palate. Um There's very characteristic facial features that one becomes familiar with. Um mainly a mono brow, low set ears and upturned nose and a gastro esophageal defect. It's apologetic disorder. Schnitzel syndrome is um notary Sh Insel syndrome. So it's not Schnitzel. Schnitzel syndrome is an ulnar mammary syndrome. It's an underdevelopment of postaxial structures and poor development of mammary glands and sweat glands. They often have hypertrichosis in infancy and feeding structured abnormality. So, abnormalities of the throat, the esophagus and because of this most do not survive infancy. It's a de novo mutation. Um um once again, treatment is about function. Um And um and you have to do more about the fingers here because inevitably you have syndactylism. Ectrodactyly, ectrodactyly is the the left hand. Um And um and again, it's about stabilising elbows and lengthening the forearm, very similar to radial dysplasia. Next slide, please. And I think we're just coming to the end of my talk. So I'm going to talk very quickly about amniotic band syndrome, which can lead to transverse deficiencies. It's thought to occur before, just before the 12th week, suspected. If you see distal edema and all sorts of distal deficiencies and deformities are possible. It's a disorder that affects, um, nobody quite still knows what causes it. It's a, um, and it's a very broad sort of presentation. So I think it's fair to say that we still don't understand it very well. Um uh It's uh there's an intrinsic and extrinsic theory that intrinsic theory that there's some sort of neurovascular development within the child itself, within the uh embryo itself. Um that um causes this condition, the extrinsic theory that it is literally an amniotic band, a disruption of or partial rupture of the amniotic sac that causes this constriction, but there is no band when you're seeing the Children when after they're born, you know, there's nothing there that, you know, it's not like uh I don't know how many, if you have seen a hair tourniquet around a digit, particularly around the fingers and the toes. Um And where there's actually where a little hair, um um uh coils around the digit and causes a lot of edema. Um that there's a, there's a proper extrinsic band there. I eat hair. Um That's not what you physically see when the child is born. We just think that it was there once that amniotic band but it leaves, it leaves, it's supply you can see in those top pictures there. Um There is that very telltale circumferential constriction then. Um um and um and, and, and, and, and an early release can give you a very nice cosmetic result in severe cases. I've never seen this personally, I've only heard of this. Um You can see that there's a total transverse deficiency below the knee and there's that edematous foot lying on the bed next to the baby. Um um as that was delivered afterwards. Um so, but yet occurred somewhere in utero. I mean, I can't believe that can be um amniotic band syndrome. I think it was probably amniotic band syndrome causing a tiny little constriction. Um And then when they delivered the baby, um it would have split open it sort of cut the um it tore off next slide, please. So when you see a baby with an upper limb deficiency, ask or deformity, ask yourself, is there a deficiency here that is there an absence here? Is it pre or post axle? Then ask about the antenatal history and the family history. What was, is the mother on anti epileptic medication? Was there some terrible illness that occurred at about a week? 7 to 10? Is there a genetic history perhaps and then are there associated symptoms? And lastly, this is a newborn? It's very good to have a positive attitude, I think. Go in. Congratulations on your baby girl. Congratulations on your baby boy. Whatever you do, leave them with positivity and hope. Um, and um, because at that stage, the parents are numb, they've just been through birth and, um, and they're going to ask you 600 questions during the next two or three consultations and that's entirely appropriate, but you want them to still celebrate that baby's birth. Thank you very much. Let's have some questions before we hear Mr Merchants um embryology talk, Mike. Thank you very much. Yeah. Um I appreciate it. Uh Can I also elbow range of motion for radio dysplasias? Is that just purely to guide treatment? Because some of them will have elbow dislocations? Yes. But can they move their elbow even if they've got a dislocation? You know, that's um can they move it enough to get their hand to their mouth? That's what I just did. Yes. It's such a basic thing, isn't it? It's um um we don't always value what we've got. You're welcome. Can I ask a question about the radio Hope plasia? Yes. On some of those X rays they had the thumb metacarpal but no phalanges. Yes. So is that what happens? They have absolute radius and the thumb hyperplasia is just loss of the phalanges. So that is, you know, hyper thumb hyperplasia can be anything from just uh I've got a relative hyperplasia of 11 of my thumbs is smaller than the other. Um, that's, um, that's a hyperplasia. Um, but it's, um, but it's perfectly strong and functional, um, with every structure I suspect present either I'm not aware of any missing structure functionally to, to, to, but yet a thumb hyperplasia is also somebody who's just got a little nubbin of a thumb. You know, I'm not a, um, a tiny stump of a phalanx or, um, uh, or just a little soft tissue nubbin at the end of the metacarpal. That's still thumb, hyperplasia. Okay, thanks. Yeah. So, but they all have it people with radial um, club hand or radial dysplasia, radio lot plasia. They all have some degree of radial deviation of their wrist, their, their hand and they have some degree of thumb hyperplasia. Can I just ask a question uh about the management? Um You mentioned about uh one of the main treatment is to make sure they joints remains congruent and ensure. No, no, no. Are you will not get congruent joints? Okay? Yeah, you're stable because there's no radius, you know, there's no. Um So you can't get a congruent joint. Okay. So, maintaining that stability, how, how do you, how do you often review them on a weekly basis or how, how do you do this? You know? Um Well, first of all, I there's not an operation I've ever done. I've only ever assisted on this, but no, you don't, you don't review them on a weekly basis. Um, this is the NHS. Um, you, uh, you know, therapist maybe even a bit more regularly than we do. Um, no, we, um, we stabilize it, we splint it a post operatively. We cast it. There's a, especially they're being lengthened. There's maybe then that they might be being seen on a lengthy, a weekly basis. But no, once, once the centralization procedure is done, it's pinned in place and you take the cast off at about week six, you might need to see them initially for them in the week, week one and week two for the soft tissue wounds. Thanks. Yeah. Does that help? Yeah. Okay. Right up next. Or should we go for a little break? How does everyone feel?