Surgical Approaches to the Lumbar Spine - Justin Paquette, MD

Sechrest: Hello, I am Dr. Randale Sechrest your host for eOrthopodTV. Today I have with me as my guest Dr. Justin Paquette. Dr. Paquette is a neurosurgeon who practices complex spine surgery in Los Angeles, CA. Dr. Paquette did his medical training at Albany Medical College. He then went on to complete a residency in neurosurgery at the Harvard Tufts Combined Program in Boston, MA. From there he completed a fellowship in complex spine surgery in Los Angeles at Cedar Sinai. Good afternoon Dr. Paquette.

Paquette: Good afternoon.

Sechrest: Dr. Paquette today I would like to talk a little bit about different approaches to surgery in the lumbar spine or the low back. I think patients sometimes are told they need surgery from the front, sometimes they're told they need surgery from the back. Sometimes they're told they need surgery from both sides. What's the current thinking about operating on the lumbar spine from the front, the back and when do you do the back and when do you do the front?

Paquette: Sure. This does definitely get into the stylistic section of surgical technique and I think really to a certain degree it does depend upon the surgeon's preference in training as to whether they do interbody work from the front from the side from the back, but just to break it down a little bit, surgery from the front essentially is referred to as a retroabdominal retroperitoneal approach. A small incision is made to the side or below the belly button, often times by a vascular surgeon who works as an access surgeon who then will find the front of the spine, not through the abdominal contents but actually works around the abdominal contents and then pushes everything to the side. That allows you to get access to the disc space right at the beginning of the spine. Now that's a very, pretty easy shot when it comes to getting to the L5-S1 disc but the further up the spine you go becomes more problematic because it has very large veins and arteries that are growing right down the middle of the spine. In addition, there is also some very important nerves that are in that area as well. This type of technique is often times used for putting in the interbody graft whether it be cadaver bone, whether it be metal or be plastic, to take the disc out and replace the disc with one of these implants. It's a relatively fast procedure, probably could be done within about an hour or so. The problem is that it leads to a lot of scar formation over the front of the spine and the biggest concern is that if for some reason there has to be a redo surgery on the front of the spine it becomes much more risky because the scar tissue now involves the nerves, the blood vessels and everything else, so that the complication rate on going back in on somebody who has already been operated on the front is pretty significant.

Sechrest: Now in addition to fusions, the newer techniques like the artificial disc. That's currently done from the front. Is that correct?

Paquette: That's correct. They're working on other avenues for putting in artificial discs, but right now lumbar artificial discs are all put in through the front and in fact in my practice, that's the only time that I'll do an anterior abdominal exposure is for an artificial disc.

Sechrest: Now one thing I think would help patients understand what we're talking about. When we talk about the anterior portion of the spine and the posterior portion, we really talk about what's in front of the spinal nerves and the spinal canal and what's behind the spinal canal. So that, I think, is our reference to something being anterior or in the front and something being in the back. And explain for folks why that's important. I mean, why don't you just go straight through the back and go straight into the disc? What's keeping you from doing that?

Paquette: Operating from the backside of the back, it becomes more difficult sometimes going all the way to the front, and the reason for that is that again, all the nerves are there and so that actually to work into the disc, you have to kind of work between different nerves and the more you pull on those nerves, the more there is a risk of causing a prolonged nerve problem after surgery. Secondly, there's lots more blood vessels to the side of the spine and so those are in relatively close proximity also. To get a full decompression of the disc front eh back, there are risks both to the nerves, to the spinal fluid and also to those blood vessels that are there.

Sechrest: So when you attack a spine, or approach a spine so to speak, what's your preference?

Paquette: My personal preference, whether it be from a microscopic decompression or a massive scoliosis correction is to do everything from the back of the spine. There's a couple reasons for that. Number one, it doesn't involve doing incisions both in the front and the back and so we can leave the stomach alone completely and we have techniques and abilities and tools now that allow us to do all of our surgeries from the back. You know, the older days of scoliosis surgery, they thought and in order to make the spine as flexible as possible and get the best correction, you'd have to take out all the discs from the front whether it be from a retroperitoneal approach in the belly or actually approach into the chest to decompress those discs. Then, once that was done, turn the patient over and to the correction with the instrumentation. What we've found now is that just as affective if not more affective is by going all from the back and taking the spine apart by doing very special, what are called osteotomies, by cutting through the joints, by taking vertebrae apart, by loosening everything up, we can get excellent corrections only through the one incision of the back.

Sechrest: Now that's really been since we've been using the pedicle screws to get actual, a connection to every vertebral body. I mean, when I was training, you're best bet was wires that went into the lamina, the ring and around the back and that's the only really technique we had to control very vertebra. So these screws now, the so called pedicle screws that go into the vertebra allow you to really capture each one of those vertebra and hold it where you want. I mean, 20 years ago that wasn't available.

Paquette: That's absolutely correct. Before, as you mentioned, there are screws, there are hooks, a variety of instruments which held onto the spine but didn't allow for three dimensional repositioning of the spine. It was very difficult to rotate the spine, very difficult to bring the spine all the way back. The pedicle screw itself, the major advantage is that it gets purchase and positioning into the entire vertebrae. And so, not only can we bring the vertebrae back, we can push it forwards, we can spin it side to side. It's really made incredible advances into what we can do with corrective spinal surgeries. And one of the main reasons why we don't need to go from the front anymore. In addition, there's also pretty significant risks of surgeries from the front as well. There's risk to the blood vessels that are there, risk to some of the nerves that are there. In young males, there's a risk of retrograde ejaculation which is not a pleasant complication. So in my personal hands, I prefer to do every single surgery completely from the back.

Sechrest: Now sometimes we see patients who have surgery from both the front and the back. What's the rationale for performing, really what's two surgeries? One from the front and one from the back.

Paquette: There's a couple different situations where you may have to do a front/back surgery, or what's called a 360 surgery. What basically would have to happen is that you have to have severe pathology both in the front of the spine where the vertebral body is and also in the back of the spine necessitating fixing both. For example, maybe there's a tumor that's destroyed one of the bodies or a fracture that's destroyed one of the vertebral bodies in the front and the entire thing has to be removed. Doing that from the back is significantly difficult and risky and so therefore, those kind of problems are best approached by coming from the front or from the side, taking out the whole problem, doing some kind of a restorative surgery where we put in a car jack of metal or plastic and replace the vertebrae, then flip the patient over, at the same time, decompress the nerves and then secure things with rods and screws.

Sechrest: Today, when a patient is faced with the decision about whether to have an artificial disc in the lumbar spine or not, that surgery is always done from the front and many spine surgeons are concerned about that because of the complications that you've mentioned already. Do you see the day where we'll be able to put an artificial disc in from the back?

Paquette: Those days are actually not that far off. Multiple companies that work in spine right now are designing implants, artificial discs, which we would be able to put in either directly from the back or kind of from the side a little bit and I think that those discs show great promise because it will negate the need to cause all the scar tissue in the front of the spine. Now we'll have to wait and see 'cause obviously they may have their own issues. However, it certainly does sound to be much more advantageous to be able to put it in from the side, not the front.

Sechrest: Question for you. If a patient is faced with trying to decide whether to have an operative procedure from the front versus the back, what advice would you have for that patient? Are they getting a good quality advise or would you steer them to a second opinion and consider surgery from the back.

Paquette: Surgery from the front I would only entertain in a couple different situations. A younger patient and very good quality, preferable a female. If you a one level disc, either an artificial disc or a one level fusion from the front, without much leg pain, those patient's will do very well and they'll probably recover a little faster because you haven't had to touch the muscles in the back. However, under almost every other condition, I would recommend doing it from the back for a couple of different reasons. Number one, you can avoid the scar tissue being formed in the front. Number two, most individuals are going to have some components of leg pains, leg problems, which means the nerves are being pinched as well. When you go from the front, sometimes it can be difficult to fully decompress those nerves as well, whereas from the back, you're actually looking right at the nerve and you can make 100% sure that nerve is decompressed as you do the rest of your work. You also have to go from the back if you're going to put in screws and so if you decided to do the front, you automatically have put that person into a front/back surgery because just to put in the screws you still have to go back there and so my personal approach to them would be, you probably want to have everything done from the back. Make sure it's being done as minimally invasively as possible with the smallest amount of incision and the least amount of injury to the normal structures in the back which is a key issue unless they think that there is a specific reason why they want to go from the front. One small little problem, looking for an artificial disc or something like that.

Sechrest: Now, just to clarify, you said you would prefer to do this on females from the front. That's because of the complicaiton that it may affect sexual function in men and that complication is not present in females?

Paquette: Correct.

Sechrest: Well great, this has been a useful discussion. I think for patient's who are trying to understand all the different advise they get for surgery in the front, surgery in the back and sometimes two surgeries, either at the same time or at two different times which used to be a common occurrence where you would do surgery in the front, come back a week later and then do surgery in the back. Any final comments for patient's trying to make this decision? Anything we have not covered about the difference and the benefits and the risk of front versus back surgery?

Paquette: A few more things that I like to explain to my patients when we're going over the exact techniques of the surgery is the advantages that we now have at our disposal to maximize the chances of the fusion and their recovery. Not until recently did we have certain types of screws and certain types of instruments which are really very useful in getting just the right position in the purchase of the spine, in the correction. However, we've also developed something called bone morphogenic protein recently. Now this is a genetically engineered recombinant protein, it's found in all of our bodies, but in very, very small amounts. And what these little proteins do is they basically tell our bone forming cells at the site of an injury, to start forming bone. They just light that activity on fire and so we can get bone fusion and bone healing much, much faster and a much greater success rate than we ever could have before. What we do with those BMPs or bone morphogenic proteins is we put it inside the little graft or the implant that we're going to slide into the disc space between the bones and so it's kept, the bones themselves are jacked up by this implant and inside the implant is a little sponge containing those BMPs and that will help the bone to form and heal very strongly in those areas. Another reason why I think that a posterior only or a surgery from the back is still very successful.

Sechrest: So, in what you're saying is that you can get away with this minimally invasive technique from the back because we're not worried about packing so much bone graft in that disc space. In the old days we had to just expose more and more so that we could get as much bone graft as we could into that space to try to promote healign and then stand back and hope that the body healed it.

Paquette: That's absolutely correct.

Sechrest: And so we've got a fertilizer now, so to speak. We've got something that can stimulate that healing. Do you think that we'll ever get to the day to where you simply inject that material into a disc space and have it fuse?

Paquette: I think we will. In fact, we're already at the stage where certain individuals are trying this. From two different pronged approach. One approach is, let's inject some of the BMPs into the disc space and try to maximize a fusion with some early interesting results. The other approach which I think is even more interesting is to inject transplant cells or fetal cells into the disc to try to regrow the disc itself and to avoid a fusion. Certainly many companies are working on that technology right now. We're still many years away from that, but that I think will be an amazing advance to putting us out of a job. You know, decreasing the amount of times that fusion surgeries need to be done.

Sechrest: So you'll have a different job, you'll basically just try to get a needle in there and your job will be easy.

Paquette: I'll be doing the injections.

Sechrest: Okay, well thanks for the information and help clarify for patients what they should be considering in terms of spine surgery, how it's done, whether it's recommended from the front or the back or whether someones recommending two surgeries. Thank you very much.

Paquette: Thank you.

Sechrest: Thanks for watching today. If you have questions about the topic that we discussed today, or any orthopedic topic, be sure to visit eOrthopod.com and if you're an orthopedic surgeon or health care provider interested in participating as a guest on eOrthopodTV, you'll also find instructions on how to apply to become a guest on the eOrthopodTV. Thanks for watching.