Minimally Invasive Spine Surgery - Ty Thaiyananthan, MD

Dr. Sechrest: Hello, I’m Dr. Randale Sechrest, your host for eOrthopod.TV. Today I have as my guest, Dr. Ty Thaiyananthan. Dr. Thaiyananthan finished his medical school training at the University of California San Francisco. From there he complete a neurosurgical residency at Yale. He completed a complex, minimally invasive spine fellowship at Cedar Sinai in Los Angeles. Today, Dr. Thaiyananthan is the Director of the Neurosurgical Spine Center at University of California Irvine. Good morning, Dr. Thaiyananthan.

Dr. Ty Thaiyananthan: Good morning, Randy. Thanks for having me.

Dr. Sechrest: Dr. Thaiyananthan, what I’d like to discuss over the next 30 minutes or so is a relatively new advance in lumbar spine surgery or surgery in the low back, and that’s the rise of minimally invasive lumbar surgery. Now I understand that that is one of your specialties is doing minimally invasive surgery of the lumbar spine. So, start out by telling us what is minimally invasive surgery?

Dr. Ty Thaiyananthan: That’s actually a very good question. I think there’s a misconception that minimally invasive surgery involves surgery that’s through the smallest incision. Sometimes that’s true. I think some of the technology makes it amiable toward small incisions. But essentially, minimally invasive surgery is surgery that preserves the normal anatomy while you undergo the surgery. So you’re minimally disrupting the muscles, you’re preserving some of the normal anatomy as you go about doing what you need to do. It’s beneficial for patients obviously because you’re not disrupting the normal anatomy, they tend to do better. They recover faster. They maintain a lot of their normal function after surgery, the normal motion. For the surgeon, it makes the access sometimes easier. Sometimes the surgical procedure takes less time, there’s less blood loss. All of those really make it an attractive option for treating patients. When we talk about minimally invasive surgery we talk about a procedure that may involve needles. Sometimes the surgery is done through tubes that allow for good visualization. There’s use of a lot of endoscopic cameras at times to help with visualization. The use of intraoperative x-rays help with these procedures, and it’s really a culmination of all these technologies that make this type of surgery possible.

Dr. Sechrest: So let me paraphrase this, and I think what you’re saying is 1) minimally invasive really not just small incisions, but less tissue damage; so what you’re really trying to do is get in, do the job, don’t damage any normal tissue that’s then going to have to heal, but just go in and try to get the job done without damaging that tissue.

Dr. Ty Thaiyananthan: That’s correct.

Dr. Sechrest: Now a couple terms, one is endoscopic. I think that there has been this trend in healthcare, especially surgery over the past 20 years where we’re not doing surgery looking at the problem, we’re doing surgery either looking at a computer screen or looking at a TV screen with a camera in our hands, or we’re looking at x-ray TV where we’re watching things go into the body on an x-ray screen and guiding that, sort of like a glorified video game.

Dr. Ty Thaiyananthan: That’s correct. That’s one of the key aspects of traditional open surgery has been that you need to visualize the pathology, directly visualize with your eyes what the pathology is as you’re operating. One of the advances with minimally invasive surgery is that we use a lot of other techniques that allow us to bypass directly looking at what we’re operating on, and what I mean by that is that we use video assistance, we use small cameras that we can place through small holes, that give us a better approach towards what we’re treating without disturbing tissues, without damaging tissues. We use x-rays in the operating room, fluoroscopes – which is a fancy word for a continuous x-ray – that we use in the operating room to help show us what position we may be in, where we may be in the spine while we’re operating. We also use computer-aided navigation, which are new techniques that have evolved to help guide us in the operating room.

Dr. Sechrest: Now, in the lumbar spine, when we’re talking about surgery on the low back, how has impacted the way you approach surgery on the low back? What sort of procedures are you able to do now through a minimally invasive surgery approach rather than actually visualizing the tissue itself?

Dr. Ty Thaiyananthan: Pretty much any pathology in the lumbar spine can be treated through a minimally invasive approach. That’s not to say that every patient should be done in minimally invasive ways. Sometimes a minimally invasive approach is maximally ineffective. So it really needs to be tailored towards a patient that’s going to benefit from that. A lot of patients will benefit from a minimally invasive approach should they decide to have surgery done. With the present technology we are able to do discectomies, we can do fusions, we can correct degenerative scoliosis, all through a minimally invasive approach, which, traditionally 5 years ago, we’d have to flay open somebody’s back, do a lot of bony work, a lot of muscle dissection to accomplish the same thing, and I think it’s really an advance for us and an advance for patient care.

Dr. Sechrest: What are the things that have made this possible. We’ve talked about the ability to make this possible. We’ve talked about the ability to visualize things, to use different modalities like the computer-guided navigation, x-ray, and the small cameras. I’m assuming that we’re talking about a whole new group of instruments and a whole new raft of devices that you could in minimally invasive.

Dr. Ty Thaiyananthan: That’s correct. Surgeons went back to the drawing board and it was a whole new series of different approaches, even surgical approaches, for the lumbar spine. Approaches that we use to do from the front and the back we now do from the side as a way to minimize tissue damage, and in doing that there had to be the development of new microsurgical tools, new microsurgical techniques, and ways to visualize and monitor the nerves and the procedure as it’s being done. So it’s really a brand new field in and of itself. That’s been a departure from what’s traditionally been done.

Dr. Sechrest: It’s relatively clear to me as a person who’s at least familiar with spine surgery to some degree how you could do a discectomy through a minimally invasive approach. It becomes more interesting when you’re talking about doing a fusion which, when I trained was, as you said, a procedure that required you to open a huge incision on the back – open up and expose, strip normal muscle away, damaging that muscle, from the vertebra that you were going to fuse, and then begin a process of straightening the spine and doing whatever you needed to do, and then completely taking the backside off of that spine and making another incision, taking bone graft, out of the pelvic bone, scooping it out and putting it in there, and allowing this mass of bone and muscle and everything else to essentially heal together as one big chunk. I think what you’re telling me now is that’s no longer done.

Dr. Ty Thaiyananthan: Right. There has been a development of new technologies such as bone morphogenetic proteins, which is a fancy name for a protein that induces bone to grow. With the development of that technology we are able to implant that into a little plastic block that’s made from a polymer that’s biocompatible or cadaveric bone, bone that we harvest from someone that’s donated their bone, and placed that in a minimally invasive fashion in-between the vertebral bodies through a small incision that then has a high likelihood of actually fusing. It’s helped us get around the necessity of getting an iliac bone graft or performing these big procedures to get a lot of surface area to make sure that the bones fuse, and it’s a very effective technology that’s really changed the way we do things.

Dr. Sechrest: Do you as a neurosurgical spine surgeon, do you actually ever harvest bone from a patient to put in another part of their body anymore?

Dr. Ty Thaiyananthan: It’s very rare. Occasionally there will be patients that we need to do that, but the indications for it are very rare. In fact, in the last year I think we’ve done only two harvests out of several hundred procedures that we’ve done. BMP has really given us the opportunity to stray away from that, which not only makes the surgery easier, but it’s really a significant benefit to a patient because traditionally what patients would complain about six months after the surgery is that, “my hip hurts” from the donor site for harvesting the bone. I think patients are very appreciative of not having to deal with that aspect and I think it really improves the outcomes and overall quality of the care that we’re able to give.

Dr. Sechrest: It’s interesting because I think patients probably don’t understand what a major advance the BMP is, because you can just assume that if you had a spinal fusion or a fusion of any bone in your body, if you had to harvest bone, you’re really getting two operations. You’re not just getting one operation. You’re getting an operation to do the procedure and a second operation to actually go in, make drill holes, and take bone away, destroying more normal tissue, that was completely normal tissue that you’re transplanting somewhere else in the body. So this is huge, just getting rid of the bone graft, almost makes this minimally invasive even if you just do the same procedure.

Dr. Ty Thaiyananthan: Makes it less invasive than what was traditionally done, absolutely.

Dr. Sechrest: Now, how do you as a surgeon, make the decision of whether a procedure, such as a fusion, or you mentioned the correction of a degenerative scoliosis, which in my mind is a big task because it involves multiple levels usually of the lumbar spine that you have to address; how can you as a surgeon make a decision as to whether that procedure can be done minimally invasively?

Dr. Ty Thaiyananthan: It really stems from understanding the anatomy and the pathology that a specific patient may have. It’s understanding what conditions can be treated through a minimally invasive approach, it’s understanding the limitations of the technology. That said, there are a lot of patients that would benefit from a minimally invasive or MIS, what we call MIS approach to treating those diseases. Degenerative scoliosis, for one, is something that we now routinely treat through a minimally invasive approach. Traditionally what we would have to do was make a big long incision, put in screws through an open approach, de-rotate the spine using rods – a fairly involved procedure. We’re now able to inserts grafts in-between the body to help straighten the spine out a little bit, place in screws and through a minimally invasive method straighten the spine out. That’s been a huge advance for us, and the technology has really made this feasible.

Dr. Sechrest: It sounds like it is an exciting advance. What do you think is in the future? Obviously this is changing on almost a week by week basis in terms of, you made the comment you’d have to figure out what is ‘doable’, it sounds like what is doable is changing on a week to week basis.

Dr. Ty Thaiyananthan: Right. As the technology evolves, we’re able to approach a lot more problems in a more effective manner in a minimally invasive approach. As it stands right now, we’re able to do quite a bit. I think the technology that’s on the horizon is really geared towards reducing the operative time, making our accuracy better, and also improving the outcomes for the patients in terms of like shortening the time that they need to spend in the hospital and shortening the time that it takes for them to recover to their normal baseline state.

Dr. Sechrest: Well, are there any drawbacks to the minimally invasive? It’s clear to me the benefit of not damaging normal tissue is a huge advance, and that alone is worth the whole minimally invasive approach. Now I would ask, what are the complications of this? Because we’re not being able to visualize, are certain structures more at risk? Is this something that we’re going to see problems down the road with? I would say the success rate of a procedure goes down because we haven’t done it adequately. What do you think and what do you see at this point as the major risk of minimally invasive surgery?

Dr. Ty Thaiyananthan: So, Randy, the risks of minimally invasive surgery really are dependent on making sure that you select the right patient for a minimally invasive procedure. I think in the hands of a surgeon that has some expertise with minimally invasive procedures, a lot of what’s commonly done can be done as effectively or better as a traditional open procedure. That said, I think the critical factor is patient selection. You need to make sure that a specific patient’s anatomy and problem can be effectively addressed with the minimally invasive techniques that we have. Not all conditions, I think, are best treated through a minimally invasive approach. There are some conditions such as spinal stenosis, which is a narrowing of the spinal canal, which can be treated through a minimally invasive approach but, in my opinion, may be better treated through a traditional open approach. I think these are all things that a patient needs to discuss with their physician and weigh the pros and cons of what a minimally invasive approach may entail versus an open approach.

Dr. Sechrest: What do you see on the horizon today in terms of disease processes that, you think, are maybe not currently treated with a minimally invasive approach, but clearly there is new technique, there is new equipment, and there are new implants, and the materials that we need to use to accomplish this on the horizon. Anything you can share with us?

Dr. Ty Thaiyananthan: Yeah, I think there are going to be advances along two tracks. One is your traditional rigid fusion or fixation procedure. I think that technology is evolving to give surgeons the ability to do that through a minimally invasive method in a very effective way. I think the other track is motion preservation technology. That, coupled with minimally invasive surgery that preserves the normal tissue, may be a powerful treatment modality for certain patients. What I mean motion preservation technology is surgery that addresses problems that a patient may have while still trying to maintain the normal motion and function of the patient’s spine. This is coupled pretty intricately with artificial disc, possible facet joint replacements, artificial facet joint replacements, that may open up a whole aspect of treatment options that we can offer patients that we traditionally haven’t been able to.

Dr. Sechrest: So let me paraphrase this and see if I understand because it’s intriguing to me. As an orthopaedist, we’re familiar with fusions, we fuse all sorts of joints and even before the artificial hip, artificial knee, even when I trained 30 years ago, if you had a young person you did not offer them an artificial joint, you basically went in and destroyed the normal anatomy and fused those, for example the knee. You would fuse it together and give that patient a stiff leg. It’s amazing to me that we’re now thinking about the facet joints, little tiny joints in the lumbar spine, the cervical spine, that I think as much as 10 years ago, we just sort of said, “when they’re bad, we just take them out and we fuse those bones together and everything’s happy”. I think we found out that everything’s not happy in the back when we do that, and trying to consider something like a knee replacement in the low back, replacing just that small joint that’s smaller than a dime, is amazing to me.

Dr. Ty Thaiyananthan: The technology is here. There are actually several devices that may be readily available soon. The artificial discs have been available for some time. I think the technology is now evolving to give us the ability to implant through a minimally invasive method. I think that’s going to be probably the next jump for minimally invasive surgery, the ability to replace those small joints in conjunction with artificial discs, may give us the ability to treat patients that we traditionally couldn’t offer a minimally invasive approach for, and would have to strongly suggest a rigid fusion for them, another option that helps maintain some of the mobility. It’s a very exciting field, I think there are going to be a lot options available in the next year that we didn’t have available to us that can really help us effectively address some problems in the lumbar spine.

Dr. Sechrest: Now if I’m a patient and I’m interested in trying to explore and do some research on my own about minimally invasive surgery and if I’m looking at having to have some type of spinal procedure in the lumbar spine, how do I go about identifying folks who may be trained and competent to offer me a minimally invasive procedure rather than the traditional approach? How easy is it to find those people?

Dr. Ty Thaiyananthan: I think there are surgeons that will be readily accessible to patients. I think the important questions the patient should ask when they do approach a surgeon is what kind of training they’ve had. Do they have subspecialty training in minimally invasive spine surgery? How many procedures have they done? A lot of this technology, because it is evolving, really involves close surgeon interaction in terms of developing the technology. The patient should ask their physician, “Are you involved in any technological studies or any innovative device trials?” I think those are all indications of a physician that may be on the cutting edge of the technology or well versed with that technology. I think it’s important for patients to ask what their complication rates are with this procedure, what the efficacy rate is. How effective is this going to be for me if we do undergo a minimally invasive procedure? I think the other questions that are important are: “If I do undergo this minimally invasive procedure, and I need some sort of revision surgery, will the traditional option still be available to me?” I think those are questions that any patient should ask a physician, a surgeon, that they’re considering letting do a minimally invasive approach.

Dr. Sechrest: Now are there minimally invasive procedures that burn bridges? For example, are there things that you can’t go back and recover from and do what we, as surgeons, would consider a salvage procedure? A procedure that is really designed to take care of a problem caused by failure of the first operation. Anything out there –

Dr. Ty Thaiyananthan: There are a few. There are some minimally invasive fusion procedures that may make it difficult for a surgeon to go back and put a graft in between the vertebral bodies; one procedure being what’s called the Trans 1 approach. It’s a minimally invasive screw that’s placed through the sacrum into the lower part of the lumbar body that may make a revision procedure a little difficult because it makes it very difficult to place a graft in between the two vertebral bodies. That’s not to say that a revision procedure is impossible, but it would definitely make it a little bit more challenging. For the most part the other procedures, such as a spinal fusion procedure, can be revised through a traditional approach, but it may involve making another separate incision. I think that it really is important for a patient to understand what may be involved in a revision surgery should the initial surgery not work adequately.

Dr. Sechrest: Is minimally invasive surgery becoming the standard of care in neurosurgical spine surgery? Is this something that, if I’m a patient, I should expect to find in my local community or is this only being done at academic centers or cutting edge research facilities at this point?

Dr. Ty Thaiyananthan: I wouldn’t go as far to say that it’s standard of care at this point. I think at some point it will be, and I think that as more surgeons are trained in minimally invasive techniques I think that it will become more prevalent. A lot of it is being done at a University setting, however, there are a lot of community physicians that will offer a minimally invasive approach to treating some problems. Again, I think it’s very important for a patient to ask what kind of training, be it fellowship training or a specific course that the physician has gone to, to assess how appropriate he may be to do that particular procedure; and I think it’s very important for them to ask just some routine questions. Don’t be afraid to ask, “How many of these have you done?” “What’s your complication rate?” “What’s your success rate?” “How do your patients do?” “How long does it take for me to get back on my feet?” “What’s the average operative time that I can expect? Is that shorter than the open procedure?” Those are very important questions for a patient to ask.

Dr. Sechrest: Anything else we haven’t covered on this topic - minimally invasive surgery of the lumbar spine? Anything that you think patients really should know before they go searching the Internet or looking at having a minimally invasive procedure? Anything we haven’t covered?

Dr. Ty Thaiyananthan: I think the most important thing is, it’s good to go to the Internet and get the information, but it really is no substitute for talking a specialist that does that. Often times we’ll see patients that come in with a whole host of different devices saying, “I’d like this done, or this minimally invasive procedure done”; and I think it really is much more complicated than that. Deciding what procedure may be best for a patient really involves understanding their anatomy, looking at their pictures, the MRI, CT scans, reviewing that with a surgeon, and getting a surgeon’s perspective of how appropriate it actually would be to be treated through a minimally invasive approach. So it’s really important for a patient to have good dialogue with their surgeon to talk about all the various options that are available.

Dr. Sechrest: Yeah, I think you made an interesting comment to that earlier and that is, ‘minimally invasive surgery can be maximally ineffective’. So I would say, paraphrasing that – you’re seeing a surgeon to solve a problem, not necessarily to buy a product or a specific procedure, and you need to let that surgeon do what he does best and guide you in what’s going to fix your problem, not necessarily whether you want to have that procedure or not.

Dr. Ty Thaiyananthan: That’s correct.

Dr. Sechrest: Well, excellent information. Thanks for sharing this with us. I think folks will get a lot of use out of it. Thanks.

Dr. Ty Thaiyananthan: Thank you.

Dr. Sechrest: Thanks for watching today. If you have questions about the topic that we discussed today, or any orthopaedic topic, be sure to visit eOrthopod.com. If you’re an orthopaedic surgeon or healthcare provider interested in participating as a guest on eOrthopod TV, you’ll also find instructions on how to apply to become a guest on eOrthopod TV. Thanks for watching.