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Spinal Deformity for Residents
Spinal Deformity: Overview
Spinal Deformity: Overview
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Video Transcription
I'm going to move forward with our first talk. It's just an overview of spinal deformity. I'm going to give you a few thoughts and ideas that I've had. This is a culmination of about 20 years of working on spinal deformity. It's a picture of beautiful Newark in the springtime. These are disclosures that I have that I don't feel are really particularly pertinent to what we're going to be talking about. Deformity. Read, read, read. You need to know your anatomy really cold. You need to know your deformity anatomy, which is a little different necessarily than just your general normal anatomy, because there are certain trends that occur over and over and over with spinal deformity. To do this kind of surgery, you should spend some time getting experience with people who've done the work before. Courses such as this are very helpful for you to learn, but you also at home need to be in your OR with hopefully a neurosurgeon in your place, but even an orthopedic surgeon in your place is another great opportunity. You need somebody who's deformity trained and comfortable for you to be in the OR. The reason is there were a lot of mistakes made in spinal deformity in the 70s and 80s, and we don't need to repeat them. We do repeat them, but we're trying to avoid that as much as possible. The difficulty when we teach deformity courses to attending is there are people later in their career and oftentimes they're already established and it's hard to get them to sit down at a table and read. With my residents at least, when you're teaching cerebrovascular anatomy or tumor surgery, at some point there's a requirement for you to sit down, look at a book or a computer and read in order to get this information down. I find more and more that the residents will, oh, I've got that because they've got something downloaded into their computer. They equate because something's in their computer with, quote, I've got that. You don't have anything. You don't have anything until you read it and put it between your ears. That's when you've got it. When it's on your computer, that's a peripheral brain. It doesn't count. Deformity's not just about screwing. Proper screw placement's a minor part of the procedure in a deformity correction procedure. For most neurosurgeons, screw placement's probably the easiest thing. There are asymmetry of the pedicles and there are a number of things that need to be accounted for. Deformity correction is not, quote, just spine. Probably knowing how to do a T-lift is of very minimal value in the deformity correction. Many of you come from programs where you're doing a fair amount of plifts or T-lifts or stuff like that. That's different than spinal deformity surgery. That will become readily apparent to you over the course of the next day and a half. Some of the principles you're learning will be helpful at home, but deformity's a pretty specific thing. As much work goes into deciding who needs surgery, when the surgery's needed, and which surgery is necessary as the actual performance of the surgery. I'd like to go over some of the general principles that we're going to be talking about in the next couple days. One thing I won't be going over in this talk will be sacral pelvic because we've got specific talks directed just for that. Sacral alignment is the alignment of C7 of the posterior aspect of the L5-S1 space. Typically that's the view that we're talking about. I'll show you some pictures as we go through, but in general we drop down a plumb line. You like the auricle of the ear, C2, C7, L1, and the sacrum all to be aligned with each other. Typically the standard criteria is a 36-inch long film standing with the patient having their hands on their clavicles, elevating a little like this. That's where you're looking to get your view from, and you're going to drop a line from C7 and see where it aligns down at the bottom. If at the bottom it aligns more than two centimeters in front of the posterior aspect of the L5-S1 space, that's considered positive sagittal balance denoted with a plus sign. If it's more than two centimeters behind that point, that's negative sagittal balance. It'll have a minus sign. Normal's within two centimeters. One thing we do know, although for young people two centimeters front or back is considered normal, it's becoming increasingly apparent that as we age that line moves forward slightly and probably higher numbers for older folks are more appropriate at this point. What are the sagittal plane values? They're pretty variable. In the cervical spine it's approximately 40 degrees of lordosis. You see an assortment of things with kyphosis in the thoracic spine and lordosis in the lumbar spine. Bridwell and Bernhardt did a whole lot of normal volunteers, and they found the numbers in parentheses there, 36 degree thoracic kyphosis and 44 degree lumbar lordosis as normal. I was taught 40, 50, 60 as a resident, but it's pretty clear that 50 and 60 are a bit of an overcall for the thoracic and lumbar curves. I think these numbers, particularly the ones in parentheses that were done with about 350 normal volunteers are probably better numbers to hang your hat on. This just shows what gravity looks like when it's properly balanced. We want to keep our head over our pelvis, and this is an uncompensated sagittal alignment. What we found from some of the work like Steve Glassman did in 2006 and then a whole bunch of publications subsequent to that is that if you're sagittally malaligned, that's much more likely to lead you into difficulties with function and pain than if you're coronally. In fact, we really work super hard today on getting you in sagittal alignment, keeping your head over your pelvis. The exact coronal curvature one way or the other is probably less important to the people today than we used to worry many years ago. The big shift was on getting the coronal alignment correct, and I think now we've realized from a function and pain point of view, sagittal alignment's more important. How do we maintain balance? We have a cervical lordosis, a thoracic kyphosis, a lumbar lordosis, and a sacral angulation that have to neutralize each other in a normal or congruent fashion. Congruency is what enables the head and trunk to line up directly over the pelvis. This facilitates a transfer of your weight through your femoral axis to maintain your center of gravity, and it's essential for normal gait and posture. Classification schemes are schemes by Moe, King, and Lenke. Lenke's the one that pretty much is the Bible at this point for what we're using. Again, we used to have a talk on this, but frankly, it takes some time to read it. You have to read these, read them again, read them again to imprint them on your mind. Having it in your computer doesn't count. Reading it counts, but we're not going to have a whole lecture on that. We've replaced that with sacral pelvic at this point. Couple concepts. The neutral vertebra. What is it defined as? It's the first vertebra in the curve where the pedicles are equally visualized. You can see I put an arrow there. That's up around T9 in this case. We have no rotation in the neutral vertebra. That's important because as we're trying to do stabilization, which vertebra is the neutral vertebra will oftentimes impact on where we're going to end a construct. Same thing with the stable vertebra. That will be the first vertebra in a curve that's bisected by the central sacral vertical line. This is an example. Draw a line across the iliac. Drop a perpendicular from the central part of the sacrum and see where it crosses the spine. This is an example here of coronal balance on the slide on my left. You can see the patient is coronally imbalanced to the left-hand side. Then sagittal balance again dropping down from C7. This would be an example of a negative sagittal balance. Same picture there. Cob angles, we used to have to put lines under the vertebra, draw a perpendicular, another line, draw a perpendicular, measure the angle. Now your PACS system does it all for you. Just put a line on it. Pick the end vertebra of each curve, put a line there, and virtually all the different systems nowadays will give you the numbers so you don't need to do your geometry the way we used to. A couple of examples of the way we do cob angle measurements on the sagittal plane. We do cob angle measurements on the anterior-posterior view. What's real important is for any deformity cases, you should be getting standing long films routinely. I can tell you in my practice, any case that I'm doing that's more than a microdisc, I'm getting long films on all the time. You need to decide if the patient you're considering for surgery is strong enough to undergo surgery. I am astounded at points when I see people, friends of mine, give talks at these kind of meetings and show T2 to the sacrum plus iliacs on like 80-year-olds. I'm just in awe of people who can do that surgery because if I did that, I think the complication rate in my hands might be unacceptable. You have to evaluate people's cardiac, pulmonary, renal, and endocrine status. Evaluate their bone, their nutritional status. Do they have systemic diseases? Very importantly, I think, is the patient a smoker. Almost all deformity surgery is elective. If you have a person unwilling to quit smoking, you want to seriously consider whether or not you're going to do a big deformity surgery that has an increased likelihood of failing with a correctable problem such as smoking. It's becoming increasingly unclear whether it's the smoke, whether it's the nicotine, or whether it's the tar. We used to think it was the nicotine was the problem. Now it's pretty clear that there are other factors besides just nicotine that hurt fusion rates in smokers. Bone density is super important. When I'm evaluating a patient, I want to know are they normal, are they osteopenic, or osteoporotic? When I'm making a decision for what I'm going to do, I feel comfortable with normal bone, putting screws in it, and moving normal bone. With osteopenic bone, I feel comfortable putting screws in and maybe exerting some force on different areas and locking it in. If you put screws into osteoporotic bone and then try and move osteoporotic bone with the screws, it's very likely you're going to run into some difficulties. You want to use T-scores. You don't want to use Z-scores. You want to know a T-score is matching to a normal 30-year-old is what it's regulated to, and that's the numbers you want to use for adult patients on deformity. Z-score is more for age-matched, and you typically would use that with children, but as a general rule when I get a DEXA report, I'm looking at the T-score, and the T-score will give you minus ... It'll be anything positive to minus .9 is normal. From minus 1.0 to minus 2.4 is osteopenia, and minus 2.5 or more negative than that is osteoporosis. That's a World Health Organization that puts out that information, and I think it's very important to know the bone density. You can get an idea from plain films, and in fact oftentimes we do, but if you're really looking to do a major deformity surgery, unless the plain films are a young person showing great bone, if you're talking about doing an older person where you have any question at all, I think doing some form of formal assessment of their bone mineral density is a worthwhile thing to do. DEXA is a great way to do it, another way to do it, particularly if they've had a bit of previous surgery that can obscure some DEXA results, you can do a quantitative CT as well. It's a bit more radiation and a bit more of an issue to do that, but you may want to consider that if you're not able to get a good DEXA scan. Smoking. Cigarettes have a clear correlation with fusion rates. There are increased wound healing problems, increased difficulties with the ventilator, adverse effects on bone mineral density. We're not entirely clear yet what the situation with cigars are because we don't have enough data on that. What are the expectations? This is really important. We're going to go into a few days' worth of operating on people and talking about surgeries, but you need to know what are the expectations with respect to appearance, pain, and function. On appearance, adolescents want an improved body image. They feel crooked. They want to be straight. They want to look like their friends. They tend to be realistic, though, in their expectations. Adults want an improved body image, and they tend to be unrealistic. As far as pain goes, most of our adolescent patients that we get don't have pain. They're crooked. They're coming to you because they've got a curve, but they rarely have pain, at least in my practice. The adults who come to me typically do have pain. It can be radicular. It can be axial back pain, or it can be a combination of the two. The pain the adults have is usually progressively worsening. Lastly, function. Again, the adolescents typically are normal. They're seeing you because they have a curve, and they want it corrected, but they're going on living life, and very often, if you're talking about 13, 14-year-olds, they're fine. Adults will have a limited function, and they usually are having a progressively worsening loss of function when they come to see you. The factors that are going to affect expectations are the patient's expectations of the surgery. These are really important to discuss in your initial meeting with the patient. Surgeon's expectations. You have to attempt to be realistic. You have to spend time with the patient and the family and clarify. If they've got a huge, stiff curve, and you're going to partially correct it, you don't want the patient coming out of your office when they're deciding on surgery thinking, oh great, I'm going to have deformity surgery, I'm going to be perfectly straight, and I'm going to be back to normal and be 20 again when you're talking to a 60-year-old. No 60-year-old that you operate on is going to be 20 again. It doesn't work that way. They're going to be 60 when you're done. You're just hopefully going to be putting them into a better alignment, and hopefully lessening their pain, hopefully improving their appearance, and hopefully improving their level of function. I'm going to give you a couple case examples just to start us off, and then we'll move on to the next set of lectures. Case one example is a 24-year-old female grad student. She initially was diagnosed at age 13 with scoliosis. She never wore a brace. She saw me. She was having no back or neurologic problems. She just noticed her clothes were fitting differently. She had had an x-ray a year before I saw her where she had a 38-degree curve. When I filmed her, she had a 43-degree curve. At that point, she had progressed five degrees in one year and was at above a critical number where it was reasonable to consider going ahead with surgery, and the diagnosis at that time was just an untreated progression of an adolescent curve. She had good flexibility in her lateral bending, and I find that more and more when you get these people in their 20s who have an untreated adolescent curve. Many of them still, the typical teaching is the young people have flexible curves. The older people have inflexible curves. However, 20s is a kind of funny number to deal with because, in my experience, most of them are behaving more like the adolescents than they are like the adults. In this particular case, because she had a flexible curve, I just looked to do the structural curve, a T4 to L1, leaving the lumbar alone because when you have a curve that are flexible, lumbar and thoracic, if you correct the structural curve, the compensatory curve will straighten itself out. This is what she was preoperatively, and that's what she was postoperatively. There was no attempt to extend down into the lumbar spine. There was no need to, and you're able to get a good coronal balance. You can see on the post-op film right on, and then on the post-op lateral, she had started out in a significant negative balance. She's a little bit less negative now, but she's still in a negative balance. This is the way she's used to walking around, and she's real happy. A couple of years out now, she's a Pilates and yoga enthusiast to this day. She works out in the gym. She's pain-free and symptom-free at two years. Second case, 15-year-old gal with diagnosed scoliosis in 2005 on a routine screening. When I first saw her, she was five feet, half-inch tall, 108 pounds. She was on her track team. All she complained about was crookedness. That was it. Her menses had begun in April of 06. That's an important question, too, in the adolescent group. She'd been treated with PT and some home exercise. She never had bracing. Somebody had prescribed a Jewett brace, which she never used. She had no past medical history or prior surgery, a normal neuro exam. Her measurements in 2005 from T5 to T11, she had a 45-degree curve, and from T11 to L3, she had a 28-degree curve. Two years later, and she had not been treated, frankly, I think in 05, she should have been treated. I wasn't seeing her at that point in 05. She was seeing her primary medical doctors for pediatrics, and she got referred to us in 2007. At this point, she's 62 degrees and 39 degrees, which is an appreciable increase. I'll show you the two side by side. Her right shoulder is elevated at this point. The iliac crests are equal. This is a 3D image, which the main value of these is they look cool when you're showing a presentation, and they spin around. I don't really use them for anything other than that. But this shows what 2005 looks like to 2007, and you can see a significant curve progression has occurred. Her pre-ops scoliosis film right there. The one thing of interest here, she's in a good sagittal alignment with a negative sagittal balance, and she's coronally aligned. That's why she's not having trouble functionally. That's why she's on the track team competing, because her alignment is reasonable both sagittally and coronally, so it's really an appearance issue at this point. We do bending films, and her right bend shows that her thoracic curve corrects, and her left bend shows that her lumbar curve corrects. This is important to demonstrate the flexibility so you know what you're going to get into when you're doing the surgery. This is intraoperative before and after we put the rods in, and this shows what she went from preoperatively to postoperatively. Interestingly, her post-op height was 5 feet 4 inches tall, so three and a half inch correction in her height. For any of you vertically challenged out there, there's hope. And again, this is a sagittal view postoperatively. Last case I'm going to show you is a lady I saw in my office yesterday, adulty gen thoracolumbar curve at a 64-year-old lady. She had bending films that demonstrated a surprising amount of flexibility. She said at age 40 she was straight. She's convinced that she was straight. We had no films to demonstrate that, but she had really been progressing over the past five years. Just a reminder, whenever you're doing OR positioning, this is not the patient I operate on. You want to use some kind of a frame that allows you to extend the hips as much as possible. The more you extend the hips, this is a Jackson frame right here, a Jackson table. The more you extend the hips, the more you put the lumbar spine into lordosis. Wherever you fixate the spine, that's what you're going to get. So it's real important in the lumbar spine to get as much lordosis as you can on the table. These are her one-year post-op x-rays done yesterday morning in my office, and she's doing wonderfully. She's pain-free, feels like a million bucks. She's a lot straighter. This is what she looked like, and she actually said, Doctor, I have a tiny little bit of asymmetry here in my ... I mean, this is talking about patient expectations. At the very top of her incision right here, there's a little bit of an asymmetry. I mean, we took a 42-degree curve and made it five degrees, and she's like, I'm a little bit asymmetrical. Manage expectations, but in general, she's having a great level of function and pain, and I think a very good appearance. This is what she was preoperatively in April of last year, and this is where we got her to in May of this year, doing a T9 to L4, and again, we're using the stable and neutral vertebra as we're trying to pick where to end our construct, and I'm real comfortable with that post-op result. That was yesterday in the office. Some conclusions before we move to the next talk, and this is one thing I want you to remember as you go through the talks. Some people are not fit for major deformity surgery. They have too many medical problems, pulmonary problems, they're smoking, their bone's not strong enough. Those people probably should not have really big deformity operations done. Maybe a smaller decompressive surgery might be a better choice. Maybe no surgery's a better choice. I can tell you, when patients come to your office with a significant deformity and pain, and they want to be straightened out, they've heard, you're the guy. I'm here to see Dr. Smith because he's going to make me straight and back where I was before. It doesn't always work that way, and you have to manage your own expectations and your patient's expectations. Try and improve your patient's fitness before you rush to surgery. This is elective surgery, it's not an emergency. Get them to quit smoking. When indicated, try a weight loss program. Improve the bone mineral density if necessary. If you have somebody with osteoporosis, treat it. I've had many patients where I treated them with a year of Forteo, improved their bone density, and then went ahead and did surgery. These are important things to consider. When you're new in practice and you're just getting ready, and you have a big deformity, you're like, all right, I'm ready, I'm ready to tackle it. Take a couple deep breaths. Don't rush into these surgeries. They don't need to be rushed. I think that's all I have for you today. Thank you.
Video Summary
The video is a lecture on spinal deformity. The speaker provides an overview of spinal deformity and shares their thoughts and ideas based on their 20 years of experience in the field. The speaker emphasizes the importance of understanding deformity anatomy and recommends gaining experience by observing and working with experienced surgeons in the operating room. They also discuss the mistakes made in spinal deformity surgery in the past and the need to avoid repeating them. The speaker highlights the importance of reading and studying deformity anatomy to truly understand it, rather than relying on downloaded information. They mention that deformity surgery involves more than just screw placement and discuss the factors to consider when deciding who needs surgery and which surgery is necessary. The speaker also touches on patient expectations and the importance of managing them. They conclude by advising new surgeons to take their time and not rush into complex deformity surgeries.
Asset Subtitle
Presented by Robert F. Heary, MD, FAANS
Keywords
spinal deformity
deformity anatomy
experienced surgeons
spinal deformity surgery
reading and studying deformity anatomy
patient expectations
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