Episode 16 - Picture This: Understanding Spinal Imaging
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Episode Summary
One of the most common responses to feeling back pain is asking your physician for an x-ray to determine what’s causing it. However, the process of coming to diagnosis to properly treat any pain goes more than just reading off of an x-ray or MRI test result.
In this episode of Back Talk Doc, Dr. Sanjiv Lakhia gives a rundown on how physicians determine the proper dedicated imaging option needed for a patient. Numerous factors affect decision-making as each scenario is different. First, the doctor takes a look at the medical history and identifies any red flags such as a history of cancer, unexplained weight loss, and other neurological symptoms.
For many cases, if there are no alarming red flags, then conservative care is suggested first before undergoing any type of imaging test. When the pain isn’t managed after, then the physician may require either an x-ray, MRI, or CAT or bone scans. Dr. Sanjiv also discusses the best and most effective imaging option for certain spine conditions, including herniated discs, spinal infections, osteoporosis, cancer, and other rare conditions.
At the end of the day, if your physician does not suggest any type of imaging, then you may have a low risk for any serious condition. Conservative care is always recommended to spare you any unnecessary testing and radiation. The majority of low back pain, in particular, is going to be self-limiting and with the proper management will resolve after some time.
Key Moments in the Episode
Red flags that affect the physician's decision-making process 03:19
Low back strain 08:10
Radiculopathy 09:30
Herniated disc 10:43
Considerations bout gadolinium 12:45
Lumbar spinal stenosis 13:13
Cauda Equina Syndrome 15:27
Spinal infection 16:24
Malignancy or cancer 17:44
Osteoporosis 20:43
Disc herniations 22:14
Links Mentioned in the Episode
The Use of Imaging in the Management of Patients With Low Back Pain by Dinesh Rao
Worth a Shot? Spinal Injections with Dr. Andrew Sumich
Cutting Edge Surgery with Dr. Mark Smith
The Narrowed Path, Understanding Spinal Stenosis with Joe Cheatle MD
Back Talk Doc is brought to you by Carolina Neurosurgery & Spine Associates, with offices in North and South Carolina. To learn more about Dr. Lakhia and treatment options for back and spine issues, go to backtalkdoc.com. To schedule an appointment with Carolina Neurosurgery & Spine Associates, you can call us at 1-800-344-6716 or visit our website at carolinaneurosurgery.com.
One of the most common responses to feeling back pain is asking your physician for an x-ray to determine what’s causing it. However, the process of coming to diagnosis to properly treat any pain goes more than just reading off of an x-ray or MRI test result.
In this episode of Back Talk Doc, Dr. Sanjiv Lakhia gives a rundown on how physicians determine the proper dedicated imaging option needed for a patient. Numerous factors affect decision-making as each scenario is different. First, the doctor takes a look at the medical history and identifies any red flags such as a history of cancer, unexplained weight loss, and other neurological symptoms.
For many cases, if there are no alarming red flags, then conservative care is suggested first before undergoing any type of imaging test. When the pain isn’t managed after, then the physician may require either an x-ray, MRI, or CAT or bone scans. Dr. Sanjiv also discusses the best and most effective imaging option for certain spine conditions, including herniated discs, spinal infections, osteoporosis, cancer, and other rare conditions.
At the end of the day, if your physician does not suggest any type of imaging, then you may have a low risk for any serious condition. Conservative care is always recommended to spare you any unnecessary testing and radiation. The majority of low back pain, in particular, is going to be self-limiting and with the proper management will resolve after some time.
Key Moments in the Episode
Red flags that affect the physician's decision-making process 03:19
Low back strain 08:10
Radiculopathy 09:30
Herniated disc 10:43
Considerations bout gadolinium 12:45
Lumbar spinal stenosis 13:13
Cauda Equina Syndrome 15:27
Spinal infection 16:24
Malignancy or cancer 17:44
Osteoporosis 20:43
Disc herniations 22:14
Links Mentioned in the Episode
The Use of Imaging in the Management of Patients With Low Back Pain by Dinesh Rao
Worth a Shot? Spinal Injections with Dr. Andrew Sumich
Cutting Edge Surgery with Dr. Mark Smith
The Narrowed Path, Understanding Spinal Stenosis with Joe Cheatle MD
Back Talk Doc is brought to you by Carolina Neurosurgery & Spine Associates, with offices in North and South Carolina. To learn more about Dr. Lakhia and treatment options for back and spine issues, go to backtalkdoc.com. To schedule an appointment with Carolina Neurosurgery & Spine Associates, you can call us at 1-800-344-6716 or visit our website at carolinaneurosurgery.com.
Intro: 00:01
Welcome. You're listening to Back Talk Doc, where you'll find answers to some of the most common questions about back pain and spine health. Brought to you by Carolina Neurosurgery & Spine Associates where providing personalized, highly skilled and compassionate spine care has been our specialty for over 75 years. And now it's time to understand the cause of back pain and learn about options to get you back on track. Here's your Back Talk Doc, Dr. Sanjiv Lakhia.
Sanjiv Lakhia: 00:37
In my world, pain is what brings people to the office. Particularly when you're dealing with back pain, you can generate quite a bit of fear and anxiety. So I understand that. And when I see patients on a weekly basis, I keep that in mind that people are here to find out what's wrong with them. And one of the ways that individuals want to have information is through dedicated imaging. It's one of the most common questions I get in the office. And I talked briefly about it in my book, Back Talk, but there is an expectation that if you hurt your back, you need a picture. So on today's episode, I want to really break down in a simple manner for you listeners to understand as much as I can about spinal imaging, low back imaging and by imaging, I mean, x-rays, MRIs, CAT scans and bone scans.
Sanjiv Lakhia: 01:30
I think it's important that if you've hurt your back, that you have a general understanding of what types of modalities are out there. What are the indications for usage and trying to understand the decision making process that your physician may be going through when trying to work up your symptoms or compliance. So, as we've talked before, low back pain is such a massive problem in this country and imaging itself, a recent analysis in 2014, looking at Medicare spending showed that the range of spending on spinal imaging ranges from $80 to $250 million. And what I want to do today is go through a very nice article that I came across, it's a review article titled The Use of Imaging in the Management of Patients With Low Back Pain. And this has been published, the authors Dinesh Rao, R-A-O, with colleagues out of the department of radiology and community health and family medicine from the University of Florida College of Medicine. And the article is written a little bit more from a primary care slant, but I thought it was well put together and could be quite useful for education and for today's podcasts.
Sanjiv Lakhia: 02:40
So hopefully by the end of the podcast, you'll have a better understanding about what types of images are out there and really when you should expect to receive one as a patient. So as we start out here, I think individuals that come to see me who have just hurt their back recently, and typically through some mechanism, whether it's lifting, pushing, or pulling, I want you to understand my mindset and kind of my workflow as I go through the decision making process. And one of the terms that you may or may not hear about is the idea of red flags. So let's talk about that briefly.
Sanjiv Lakhia: 03:19
So let's say you're out working on your yard. And I actually just had this, this morning where a patient was pulling on some weeds and she came into the office saying her back has been hurting since Saturday. So right away myself and any other spine physician is going to go through the history and look for what we call our red flags. So red flags are symptoms, and we use the analogy red flag, simply because the color red implies danger or there's something really ominous that could be going on. So as I review the paperwork and I look through her history, or I look through your history, there are certain elements that we're looking for that we call red flags. And number one could be a history of cancer because that can be very concerning, particularly if someone comes in with back pain, without an explained mechanism of injury. Unexplained weight loss, again, not weight loss from diet and exercise, but just a gradual weight loss over a course of time of really an unclear reason.
Sanjiv Lakhia: 04:17
And that can be an indicator also of some type of cancer in the body That's increasing metabolic rate and promoting weight loss. So low back pain with unexplained weight loss, low back pain with a history of what's called immunosuppression is a red flag. Immunosuppression is really, if you have any condition that is known to suppress your immune system, and these can be immunologic conditions or one that's commonly overlooked is immune suppression from medications that you may be on. Obviously any infection in the body with back pain is of concern. For example, you can have referred pain to your back from something as simple as a bladder infection, but of course you can have infection in the spine itself, infection in the disc. So back pain with infection. Now what's interesting about infection and we'll talk about it a little more later is that you may or may not have signs of infections such as fevers and chills or even blood work markers that are elevated in the setting of back pain that's caused by infection.
Sanjiv Lakhia: 05:21
Another red flag could be back pain with a history of prolonged steroid usage. So steroids such as prednisone or methylprednisolone Medrol Dosepak. Steroids are potent anti-inflammatories and they're often prescribed across numerous disciplines and specialties. You may receive steroids if you have an asthma attack, if you go to urgent care with a rash, you can receive steroids if you have headache syndromes, really numerous causes. It's a very potent antiinflammatory that can be taken in place of nonsteroidal anti-inflammatories like ibuprofen or Aleve. They're just more potent, but prolonged steroid usage over the course of weeks to months or even years can make your bones thin. So if you have a sudden onset of low back pain in the setting of prolonged steroid usage, it raises the red flag and concern for possible spinal fracture. I do have some patients that have a history of rheumatoid arthritis who are on low-dose of steroids chronically. So you do have to be worried about that.
Sanjiv Lakhia: 06:24
I think simple stuff like a recent fall or traumas a red flags. So if you fell down your steps and you come into see your doctor, that's a red flag, that'll trigger imaging. And the red flags themselves, what they do is they point the physician in the direction of the idea that some degree of spinal imaging is needed in that moment. Other red flags and even more concerning red flags are neurologic symptoms, in particular, a rapid onset of inability to urinate or control your bladder. In that situation, we're very concerned about conditions such as cauda equina syndrome or any sort of severe neurologic compromised cauda equina syndrome can be a compression of the nerve bundle in the lower part of your spinal canal that controls all the plumbing. And that is something that cannot be missed and needs immediate attention.
Sanjiv Lakhia: 07:15
There are some physical exam maneuvers that we'll do to help determine if an individual back pain has a serious issue. And this can involve looking at your strength, your sensation and certain reflexes as well. So numbness is also the last one I would say is a red flag. So if you have rapidly progressing numbness in your legs or numbness going up your legs or dense numbness down your leg, again, that's a neurologic sign or symptom that needs attention. So those are the red flags in the setting of low back pain that don't necessarily want to be missed. They're key elements to our history, and they guide our decision making process.
Sanjiv Lakhia: 07:55
Imaging options at our disposal include x-ray imaging, MRI imaging, CAT scan studies and bone scans studies. And I want to kind of break down these individually and even in the context of specific diagnosis.
Sanjiv Lakhia: 08:10
So let's start with the whole idea of the simple low back strain. Again, we'll go back to the example earlier of working in the yard, pulling on the weeds and your back hurts. So if you come into the office, most of the time, the physician will take the history, look for the red flags and do a detailed exam. And if you don't have any typical or any concerning signs or symptoms like weakness or loss of sensation, you're typically categorized as an uncomplicated back strain. And in that setting, plain film x-rays are typically not indicated. Most of the guidelines from the American Academy of Family Physicians, The American Academy of Physical Medicine and Rehab or the American Association of Neurological Surgeons and Congress of Neurological Surgeons typically recommend withholding all imaging of the spine in patients with non-specific, acute low back pain episodes without the red flags I just reviewed.
Sanjiv Lakhia: 09:05
So keep that in mind, I've seen that trigger some frustration in patients when they come in and feel like they need an extra way to explain their problem. The literature clearly states that the value of the x-ray is very limited in that immediate setting, in the absence of the red flags. And by not ordering the x-ray, we are sparing our patients unnecessary testing and unnecessary radiation. Different scenario though, would be radiculopathy and radiculopathy is a condition where you have pain in your back, that radiates down your leg, typically associated with some degree of numbness or weakness. So in that setting, after a four to six week trial of conservative care, the study of choice would be a lumbar MRI without contrast dye. MRI is going to be very sensitive for looking at the health of your spinal disc and look for what's called a neural compressive finding or a finding in your back that is essentially contacting or putting mechanical pressure on a specific nerve root. X-rays also can play a role if you're considering any issues with back arthritis or spinal instability, where the bones are not aligned well.
Sanjiv Lakhia: 10:16
So that's typically what I'll do if someone comes in, if they've had their initial assessment, showed pain and maybe pain down the leg, but no specific neurologic signs or symptoms. Normally we would look at a four to six week conservative care trial followed up by an MRI of the low back to give us further information, particularly if there's weakness or atrophy developing in the leg. So that's one setting which will be radiculopathy, think MRI.
Sanjiv Lakhia: 10:43
Now let's fast forward a little bit. Let's say you have been found to have a herniated disc, and eventually you go through and see one of my partners like Dr. Smith or Dr. Cheadle, who've discussed surgical approaches. And if you haven't heard their episodes, I encourage you to listen to them. Let's say you've had a micro disc surgery and then you come back to the office, maybe three to four months later with some recurrent pain in your back and down your leg. In fact, I just had this situation last week with a patient of mine, and we had this exact discussion. The question then becomes what's the imaging test of choice in that scenario?
Sanjiv Lakhia: 11:18
Well, it's pretty clear that within the first six months after a micro disc surgery, for the treatment of radiculopathy that postoperative granulation tissue can develop. What is that in layman's terms? In simple terms, what I'm talking about is scar tissue. So you can get scar tissue in the spinal canal area where the surgery has been performed and it can make it somewhat difficult to distinguish if there's a new problem such as a new disc herniation or it's just postoperative scarring. And they can look almost quite similar on an MRI. So in that scenario, we try and wait, we try and wait at least three to six months before we pull the trigger on a new MRI study. But if we do feel like we have to move forward, the typical imaging recommendation of choice is an MRI of the lumbar spine with and without contrast, and the contrast normally uses gadolinium.
Sanjiv Lakhia: 12:10
So the contrast for the dye, as we like to say, really can help distinguish between scar tissue and disc herniation. And it has to deal with the degree of enhancement of the tissues on the MRI scan, meaning they just look slightly different based upon their absorption patterns of the dye. Now, the dye is administered through the vein, so it's relatively innocuous for the patient. So that scenario, if you've had back surgery and you were having recurrent problems, normally it's going to be the MRI with contrast. That'll be very helpful.
Sanjiv Lakhia: 12:45
Some thoughts though, and considerations about gadolinium. It is a heavy metal and there have been some warnings put up by the FDA about gadolinium and its longterm absorption within the body. Normally though, if you have healthy functioning kidneys, but doesn't appear to be significant issues with retainment of the dye, but it's just something to consider. If you do have a history of kidney issues, please make sure you share that with your physician or radiologist prior to having a dye study of any type.
Sanjiv Lakhia: 13:13
Now, moving on, the other condition I want to talk about is lumbar spinal stenosis. And we did an excellent podcast interview on spinal stenosis with Dr. Joe Cheadle. So please go check that out if you're dealing with the issue. But the question becomes, how do we properly image spinal stenosis? Again, let's assume you've gone through your initial conservative care trial and you're having ongoing symptoms, back pain, some weakness in the canal. What do you do? So the key here is to try and figure out what is the degree of spinal stenosis? What is the degree of narrowing within the spinal canal that you're dealing with?
Sanjiv Lakhia: 13:47
As we know that when the canal narrows further, it can cause all sorts of symptoms, such as numbness and weakness and heaviness and pain in the legs, which is described as claudication. So in this scenario, the test of choice to image the spinal canal and essentially obtain a degree of a measurement regarding the dimensions of your spinal canal would be a MRI without contrast. So just a plain MRI study. And what's real nice is we do have some technologies at Carolina Neurosurgery & Spine, where we can actually image the back in a seated position and in a flexed and extended position, that is a position where you're bending forward and bending back, and see how it affects the dimensions of your spinal canal. Now there's different criteria to determine whether or not you have spinal stenosis based upon how many millimeters of space is remaining and the radiologist can perform the measurement for you. And most trained physiatrists and neurosurgeons can just easily look at a cross section of your MRI and determine if you have spinal stenosis. So again, a spinal stenosis, you really want to look at the MRI without contrast.
Sanjiv Lakhia: 14:54
Now, if you have a contraindication to an MRI, such as a pacemaker or a metal spinal cord stimulator, then the alternative choice there would be CAT scan with myelography. Now myelography is a procedure where you would basically go to the hospital and get a spinal tap and have the dye injected in the spinal canal and then put through your CAT scanner. But MRI has largely replaced that due to ease of access and less discomfort, less interventional aspect to just a plain MRI.
Sanjiv Lakhia: 15:27
Another condition of great concern that we mentioned before in terms of the red flags is one that's called cauda equina syndrome. Now cauda equina syndrome is typically an emergent condition, it's where you can have a rather sudden onset of dysfunction and impairment of your bowel and bladder function, sexual dysfunction and it's a lot of times associated with what we call a saddle and a seat [inaudible 00:15:47] or numbness. I like to tell patients it's numbness where the sun doesn't shine. So it's down in the area where if you were sitting on a horse, sitting on a saddle, where you're scanning and your perineum contacts the saddle, that is where the symptoms can really develop, and it can be quite frightening for individuals. Undoubtedly, the treatment and the test of choice there is an MRI study, an emergent MRI study typically at their emergency room. In that case x-rays would not have much utility. Fortunately cauda equina syndrome is not very common, although we are always on the lookout for it.
Sanjiv Lakhia: 16:24
I also mentioned when reviewing the red flags, several red flag symptoms that can suggest infection. So let's talk about the imaging options if you're looking for spinal infection, and spinal infection is usually secondary to an infection elsewhere in the body, and it can spread through your blood. For example, after a procedure or a recent surgery or trauma or even IV drug use, these are some of the risk factors for spinal infection. As I mentioned earlier, in the episode, you don't always have fever, even symptoms like chills and night sweats and weight loss are not consistently present. Blood markers can be abnormal, but they're not always reliable. MRI again, wins the day. MRI with, and without contrast is preferred imaging study.
Sanjiv Lakhia: 17:11
It has a very high sensitivity and specificity to looking for spinal infection. And you want to add the contrast dye because it helps to show the metabolic activity and show areas of infection and abscess. And it also can help you distinguish on an MRI between just really bad degenerative changes that we call modic, M-O-D-I-C, endplate change versus true inflammatory infectious reaction in your spine. Hopefully no one listening to this ever has to deal with a spinal infection.
Sanjiv Lakhia: 17:44
Now, moving on to the next category here that I want to review that's in this article, is that of malignancy or cancer. I have a lot of patients that come to see me and their mind goes straight to, Doc, my back is hurting. Do I have cancer in my back? And fortunately, statistically, less than 1% of patients that have low back pain and present, let's say to your primary care doctor, less than 1% have any sort of malignancy or cancer. There are some risk factors for it, like an insidious onset of back pain, age over 50 or history of cancer itself. Some of the solid cancers that spread to the spine most commonly include breast cancer, prostate, lung, thyroid and kidney cancer. There's also multiple myeloma, which can also present with lesions in the spine. In this scenario, understand that spinal x-ray is relatively insensitive for the detection of bone metastases or bone cancer in the spine with false negative rates as high as 40%. So if your physician has a strong concern, they would typically transition to other options. And there are several options.
Sanjiv Lakhia: 18:57
Nuclear medicine bone scan studies are standard for initial screenings for metastatic bone disease, but they're typically ordered in correlation with a CAT scan or an MRI study because the bone scan is not very specific. PET scans also can detect increased glucose metabolism or sugar uptake when combined with CAT scan and the sensitivity increases to around 75 to 95%. CAT scan studies or CT studies also provide excellent resolution and can demonstrate bone lesions really nicely. MRI, with and, without contrast though is still superior to CAT scan for detection of osseous metastasis or bone cancer or cancer spread to the bone. It's the higher sensitivity and similar specificity to the CAT scan study. An MRI is also superior for looking at characterizations of a bone tumor. So it's a very complex situation. Oftentimes it will require the input of multiple specialists from your oncologist to the radiologist or neurosurgeon in making the decision on how to properly image. But I think a key take home there is that spinal x-ray has a very high, false negative rate. So typically, further imaging is warranted.
Sanjiv Lakhia: 20:13
Now there are some other rare conditions that we look at when we're evaluating back pain. Spinal hemorrhaging is one of them. I'm not going to talk too much about that. Other than to say that a traditional non-contrast MRI is the study of choice. If we're looking for hematomas or blood clots, which can develop after let's say procedures. And again, if you want to learn more about spinal procedures, please listen to my interview with Dr. Andrew Sumich where we covered a lot about spinal injections. Osteoporosis is another condition that many individuals suffer with. I see a lot of women and men who come into my office that have evidence of osteoporosis, and I want to talk about that briefly.
Sanjiv Lakhia: 20:55
In particular, when you look at x-ray imaging for osteoporosis, understand the x-rays are not a really good test to look at your bone density, but you can see some secondary signs on x-ray that may suggest you have osteoporosis. And the main one is vertebral fractures or broken bones or slight compression deformities in your vertebral bodies. X-ray will not tell you though, if that's new or old, you have to correlate that with your presentation, with the symptoms and oftentimes further imaging, vertebral fractures are very common if you're on steroids, increasing age and particular female gender have higher incidents and prevalence ranges from around 10 to 24%. And some fractures are very, very painful and others are not. So x-ray again, is the imaging choice that has done initially. But for any lingering concerns, a non-contrast CAT scan is recommended and you also can use an MRI to kind of stage a fracture in terms of acute versus chronic.
Sanjiv Lakhia: 22:00
So that's a pretty good summary there of some of the top spine conditions that cause back pain. And then how we approach them from a system perspective, looking at the proper imaging choice. The other thing I would talk about in particular is the idea of disc herniations and how do you image them? Clearly MRI imaging is the recommended imaging modality. I do hear a lot of patients come in with some misconceptions. You really cannot see a herniated disc on an x-ray. Now, what I would say though, is a plain x-ray can show you evidence that there may be a problem with the disc. You can see the disc space on an x-ray, and that will show you how closely the vertebral bones are approximated. You can see arthritic changes around the vertebral level. You can see bone slippage. Any of these can really be suggestive, that there may be an issue with the disc at that level.
Sanjiv Lakhia: 23:07
There are some situations where the disc will calcify slightly and you can see the slight calcification in the disc space on an x-ray because that's essentially the same substance as bone and give you a really good clue about it. So again, if you're considering or wondering if you have a herniated disc, ultimately you'll end up needing an MRI study to help clarify that.
Sanjiv Lakhia: 23:30
So there you go. I hope that was helpful for you. There's a lot of options out there, a full menu of imaging options from x-rays to MRIs, to CAT scans, bone scans studies, decision making regarding the use of dye and even CT monogram studies, which are a bit more invasive. So at the end of the day, understand that when you present to your doctor with back pain, the key starting point is going to be your history and those red flags that we detailed. If you are not being offered an imaging study initially, normally that's because the probability of a concerning finding on the study is quite low and that you have to go through some conservative care to meet criteria, to qualify for the MRI or the advanced imaging study, at least from an insurance perspective. And take some reassurance that medically you're in a low risk category for having anything serious.
Sanjiv Lakhia: 24:27
Just remember in spite of all the things I discussed today, which are all very concerning from infections to cancer in the spine, osteoporosis, a majority of your episodes of low back pain are going to be self-limiting, they're going to resolve typically within a short period of time and likely not warrant any significant imaging or workup. Once again, this is all just for informational purposes. Only if you are suffering from back pain, please go ahead and see your physician and get care from a qualified professional.
Outro: 25:01
Thank you for listening to this episode of Back Talk Doc, brought to you by Carolina Neurosurgery and Spine Associates, with offices in North and South Carolina. If you'd like to learn more about Dr. Lakhia and treatment options for back issues, go to backtalkdoc.com. We look forward to having you join us for more insights about back pain and spine health on the next episode of Back Talk Doc. Additional information is also available at carolinaneurosurgery.com.
Welcome. You're listening to Back Talk Doc, where you'll find answers to some of the most common questions about back pain and spine health. Brought to you by Carolina Neurosurgery & Spine Associates where providing personalized, highly skilled and compassionate spine care has been our specialty for over 75 years. And now it's time to understand the cause of back pain and learn about options to get you back on track. Here's your Back Talk Doc, Dr. Sanjiv Lakhia.
Sanjiv Lakhia: 00:37
In my world, pain is what brings people to the office. Particularly when you're dealing with back pain, you can generate quite a bit of fear and anxiety. So I understand that. And when I see patients on a weekly basis, I keep that in mind that people are here to find out what's wrong with them. And one of the ways that individuals want to have information is through dedicated imaging. It's one of the most common questions I get in the office. And I talked briefly about it in my book, Back Talk, but there is an expectation that if you hurt your back, you need a picture. So on today's episode, I want to really break down in a simple manner for you listeners to understand as much as I can about spinal imaging, low back imaging and by imaging, I mean, x-rays, MRIs, CAT scans and bone scans.
Sanjiv Lakhia: 01:30
I think it's important that if you've hurt your back, that you have a general understanding of what types of modalities are out there. What are the indications for usage and trying to understand the decision making process that your physician may be going through when trying to work up your symptoms or compliance. So, as we've talked before, low back pain is such a massive problem in this country and imaging itself, a recent analysis in 2014, looking at Medicare spending showed that the range of spending on spinal imaging ranges from $80 to $250 million. And what I want to do today is go through a very nice article that I came across, it's a review article titled The Use of Imaging in the Management of Patients With Low Back Pain. And this has been published, the authors Dinesh Rao, R-A-O, with colleagues out of the department of radiology and community health and family medicine from the University of Florida College of Medicine. And the article is written a little bit more from a primary care slant, but I thought it was well put together and could be quite useful for education and for today's podcasts.
Sanjiv Lakhia: 02:40
So hopefully by the end of the podcast, you'll have a better understanding about what types of images are out there and really when you should expect to receive one as a patient. So as we start out here, I think individuals that come to see me who have just hurt their back recently, and typically through some mechanism, whether it's lifting, pushing, or pulling, I want you to understand my mindset and kind of my workflow as I go through the decision making process. And one of the terms that you may or may not hear about is the idea of red flags. So let's talk about that briefly.
Sanjiv Lakhia: 03:19
So let's say you're out working on your yard. And I actually just had this, this morning where a patient was pulling on some weeds and she came into the office saying her back has been hurting since Saturday. So right away myself and any other spine physician is going to go through the history and look for what we call our red flags. So red flags are symptoms, and we use the analogy red flag, simply because the color red implies danger or there's something really ominous that could be going on. So as I review the paperwork and I look through her history, or I look through your history, there are certain elements that we're looking for that we call red flags. And number one could be a history of cancer because that can be very concerning, particularly if someone comes in with back pain, without an explained mechanism of injury. Unexplained weight loss, again, not weight loss from diet and exercise, but just a gradual weight loss over a course of time of really an unclear reason.
Sanjiv Lakhia: 04:17
And that can be an indicator also of some type of cancer in the body That's increasing metabolic rate and promoting weight loss. So low back pain with unexplained weight loss, low back pain with a history of what's called immunosuppression is a red flag. Immunosuppression is really, if you have any condition that is known to suppress your immune system, and these can be immunologic conditions or one that's commonly overlooked is immune suppression from medications that you may be on. Obviously any infection in the body with back pain is of concern. For example, you can have referred pain to your back from something as simple as a bladder infection, but of course you can have infection in the spine itself, infection in the disc. So back pain with infection. Now what's interesting about infection and we'll talk about it a little more later is that you may or may not have signs of infections such as fevers and chills or even blood work markers that are elevated in the setting of back pain that's caused by infection.
Sanjiv Lakhia: 05:21
Another red flag could be back pain with a history of prolonged steroid usage. So steroids such as prednisone or methylprednisolone Medrol Dosepak. Steroids are potent anti-inflammatories and they're often prescribed across numerous disciplines and specialties. You may receive steroids if you have an asthma attack, if you go to urgent care with a rash, you can receive steroids if you have headache syndromes, really numerous causes. It's a very potent antiinflammatory that can be taken in place of nonsteroidal anti-inflammatories like ibuprofen or Aleve. They're just more potent, but prolonged steroid usage over the course of weeks to months or even years can make your bones thin. So if you have a sudden onset of low back pain in the setting of prolonged steroid usage, it raises the red flag and concern for possible spinal fracture. I do have some patients that have a history of rheumatoid arthritis who are on low-dose of steroids chronically. So you do have to be worried about that.
Sanjiv Lakhia: 06:24
I think simple stuff like a recent fall or traumas a red flags. So if you fell down your steps and you come into see your doctor, that's a red flag, that'll trigger imaging. And the red flags themselves, what they do is they point the physician in the direction of the idea that some degree of spinal imaging is needed in that moment. Other red flags and even more concerning red flags are neurologic symptoms, in particular, a rapid onset of inability to urinate or control your bladder. In that situation, we're very concerned about conditions such as cauda equina syndrome or any sort of severe neurologic compromised cauda equina syndrome can be a compression of the nerve bundle in the lower part of your spinal canal that controls all the plumbing. And that is something that cannot be missed and needs immediate attention.
Sanjiv Lakhia: 07:15
There are some physical exam maneuvers that we'll do to help determine if an individual back pain has a serious issue. And this can involve looking at your strength, your sensation and certain reflexes as well. So numbness is also the last one I would say is a red flag. So if you have rapidly progressing numbness in your legs or numbness going up your legs or dense numbness down your leg, again, that's a neurologic sign or symptom that needs attention. So those are the red flags in the setting of low back pain that don't necessarily want to be missed. They're key elements to our history, and they guide our decision making process.
Sanjiv Lakhia: 07:55
Imaging options at our disposal include x-ray imaging, MRI imaging, CAT scan studies and bone scans studies. And I want to kind of break down these individually and even in the context of specific diagnosis.
Sanjiv Lakhia: 08:10
So let's start with the whole idea of the simple low back strain. Again, we'll go back to the example earlier of working in the yard, pulling on the weeds and your back hurts. So if you come into the office, most of the time, the physician will take the history, look for the red flags and do a detailed exam. And if you don't have any typical or any concerning signs or symptoms like weakness or loss of sensation, you're typically categorized as an uncomplicated back strain. And in that setting, plain film x-rays are typically not indicated. Most of the guidelines from the American Academy of Family Physicians, The American Academy of Physical Medicine and Rehab or the American Association of Neurological Surgeons and Congress of Neurological Surgeons typically recommend withholding all imaging of the spine in patients with non-specific, acute low back pain episodes without the red flags I just reviewed.
Sanjiv Lakhia: 09:05
So keep that in mind, I've seen that trigger some frustration in patients when they come in and feel like they need an extra way to explain their problem. The literature clearly states that the value of the x-ray is very limited in that immediate setting, in the absence of the red flags. And by not ordering the x-ray, we are sparing our patients unnecessary testing and unnecessary radiation. Different scenario though, would be radiculopathy and radiculopathy is a condition where you have pain in your back, that radiates down your leg, typically associated with some degree of numbness or weakness. So in that setting, after a four to six week trial of conservative care, the study of choice would be a lumbar MRI without contrast dye. MRI is going to be very sensitive for looking at the health of your spinal disc and look for what's called a neural compressive finding or a finding in your back that is essentially contacting or putting mechanical pressure on a specific nerve root. X-rays also can play a role if you're considering any issues with back arthritis or spinal instability, where the bones are not aligned well.
Sanjiv Lakhia: 10:16
So that's typically what I'll do if someone comes in, if they've had their initial assessment, showed pain and maybe pain down the leg, but no specific neurologic signs or symptoms. Normally we would look at a four to six week conservative care trial followed up by an MRI of the low back to give us further information, particularly if there's weakness or atrophy developing in the leg. So that's one setting which will be radiculopathy, think MRI.
Sanjiv Lakhia: 10:43
Now let's fast forward a little bit. Let's say you have been found to have a herniated disc, and eventually you go through and see one of my partners like Dr. Smith or Dr. Cheadle, who've discussed surgical approaches. And if you haven't heard their episodes, I encourage you to listen to them. Let's say you've had a micro disc surgery and then you come back to the office, maybe three to four months later with some recurrent pain in your back and down your leg. In fact, I just had this situation last week with a patient of mine, and we had this exact discussion. The question then becomes what's the imaging test of choice in that scenario?
Sanjiv Lakhia: 11:18
Well, it's pretty clear that within the first six months after a micro disc surgery, for the treatment of radiculopathy that postoperative granulation tissue can develop. What is that in layman's terms? In simple terms, what I'm talking about is scar tissue. So you can get scar tissue in the spinal canal area where the surgery has been performed and it can make it somewhat difficult to distinguish if there's a new problem such as a new disc herniation or it's just postoperative scarring. And they can look almost quite similar on an MRI. So in that scenario, we try and wait, we try and wait at least three to six months before we pull the trigger on a new MRI study. But if we do feel like we have to move forward, the typical imaging recommendation of choice is an MRI of the lumbar spine with and without contrast, and the contrast normally uses gadolinium.
Sanjiv Lakhia: 12:10
So the contrast for the dye, as we like to say, really can help distinguish between scar tissue and disc herniation. And it has to deal with the degree of enhancement of the tissues on the MRI scan, meaning they just look slightly different based upon their absorption patterns of the dye. Now, the dye is administered through the vein, so it's relatively innocuous for the patient. So that scenario, if you've had back surgery and you were having recurrent problems, normally it's going to be the MRI with contrast. That'll be very helpful.
Sanjiv Lakhia: 12:45
Some thoughts though, and considerations about gadolinium. It is a heavy metal and there have been some warnings put up by the FDA about gadolinium and its longterm absorption within the body. Normally though, if you have healthy functioning kidneys, but doesn't appear to be significant issues with retainment of the dye, but it's just something to consider. If you do have a history of kidney issues, please make sure you share that with your physician or radiologist prior to having a dye study of any type.
Sanjiv Lakhia: 13:13
Now, moving on, the other condition I want to talk about is lumbar spinal stenosis. And we did an excellent podcast interview on spinal stenosis with Dr. Joe Cheadle. So please go check that out if you're dealing with the issue. But the question becomes, how do we properly image spinal stenosis? Again, let's assume you've gone through your initial conservative care trial and you're having ongoing symptoms, back pain, some weakness in the canal. What do you do? So the key here is to try and figure out what is the degree of spinal stenosis? What is the degree of narrowing within the spinal canal that you're dealing with?
Sanjiv Lakhia: 13:47
As we know that when the canal narrows further, it can cause all sorts of symptoms, such as numbness and weakness and heaviness and pain in the legs, which is described as claudication. So in this scenario, the test of choice to image the spinal canal and essentially obtain a degree of a measurement regarding the dimensions of your spinal canal would be a MRI without contrast. So just a plain MRI study. And what's real nice is we do have some technologies at Carolina Neurosurgery & Spine, where we can actually image the back in a seated position and in a flexed and extended position, that is a position where you're bending forward and bending back, and see how it affects the dimensions of your spinal canal. Now there's different criteria to determine whether or not you have spinal stenosis based upon how many millimeters of space is remaining and the radiologist can perform the measurement for you. And most trained physiatrists and neurosurgeons can just easily look at a cross section of your MRI and determine if you have spinal stenosis. So again, a spinal stenosis, you really want to look at the MRI without contrast.
Sanjiv Lakhia: 14:54
Now, if you have a contraindication to an MRI, such as a pacemaker or a metal spinal cord stimulator, then the alternative choice there would be CAT scan with myelography. Now myelography is a procedure where you would basically go to the hospital and get a spinal tap and have the dye injected in the spinal canal and then put through your CAT scanner. But MRI has largely replaced that due to ease of access and less discomfort, less interventional aspect to just a plain MRI.
Sanjiv Lakhia: 15:27
Another condition of great concern that we mentioned before in terms of the red flags is one that's called cauda equina syndrome. Now cauda equina syndrome is typically an emergent condition, it's where you can have a rather sudden onset of dysfunction and impairment of your bowel and bladder function, sexual dysfunction and it's a lot of times associated with what we call a saddle and a seat [inaudible 00:15:47] or numbness. I like to tell patients it's numbness where the sun doesn't shine. So it's down in the area where if you were sitting on a horse, sitting on a saddle, where you're scanning and your perineum contacts the saddle, that is where the symptoms can really develop, and it can be quite frightening for individuals. Undoubtedly, the treatment and the test of choice there is an MRI study, an emergent MRI study typically at their emergency room. In that case x-rays would not have much utility. Fortunately cauda equina syndrome is not very common, although we are always on the lookout for it.
Sanjiv Lakhia: 16:24
I also mentioned when reviewing the red flags, several red flag symptoms that can suggest infection. So let's talk about the imaging options if you're looking for spinal infection, and spinal infection is usually secondary to an infection elsewhere in the body, and it can spread through your blood. For example, after a procedure or a recent surgery or trauma or even IV drug use, these are some of the risk factors for spinal infection. As I mentioned earlier, in the episode, you don't always have fever, even symptoms like chills and night sweats and weight loss are not consistently present. Blood markers can be abnormal, but they're not always reliable. MRI again, wins the day. MRI with, and without contrast is preferred imaging study.
Sanjiv Lakhia: 17:11
It has a very high sensitivity and specificity to looking for spinal infection. And you want to add the contrast dye because it helps to show the metabolic activity and show areas of infection and abscess. And it also can help you distinguish on an MRI between just really bad degenerative changes that we call modic, M-O-D-I-C, endplate change versus true inflammatory infectious reaction in your spine. Hopefully no one listening to this ever has to deal with a spinal infection.
Sanjiv Lakhia: 17:44
Now, moving on to the next category here that I want to review that's in this article, is that of malignancy or cancer. I have a lot of patients that come to see me and their mind goes straight to, Doc, my back is hurting. Do I have cancer in my back? And fortunately, statistically, less than 1% of patients that have low back pain and present, let's say to your primary care doctor, less than 1% have any sort of malignancy or cancer. There are some risk factors for it, like an insidious onset of back pain, age over 50 or history of cancer itself. Some of the solid cancers that spread to the spine most commonly include breast cancer, prostate, lung, thyroid and kidney cancer. There's also multiple myeloma, which can also present with lesions in the spine. In this scenario, understand that spinal x-ray is relatively insensitive for the detection of bone metastases or bone cancer in the spine with false negative rates as high as 40%. So if your physician has a strong concern, they would typically transition to other options. And there are several options.
Sanjiv Lakhia: 18:57
Nuclear medicine bone scan studies are standard for initial screenings for metastatic bone disease, but they're typically ordered in correlation with a CAT scan or an MRI study because the bone scan is not very specific. PET scans also can detect increased glucose metabolism or sugar uptake when combined with CAT scan and the sensitivity increases to around 75 to 95%. CAT scan studies or CT studies also provide excellent resolution and can demonstrate bone lesions really nicely. MRI, with and, without contrast though is still superior to CAT scan for detection of osseous metastasis or bone cancer or cancer spread to the bone. It's the higher sensitivity and similar specificity to the CAT scan study. An MRI is also superior for looking at characterizations of a bone tumor. So it's a very complex situation. Oftentimes it will require the input of multiple specialists from your oncologist to the radiologist or neurosurgeon in making the decision on how to properly image. But I think a key take home there is that spinal x-ray has a very high, false negative rate. So typically, further imaging is warranted.
Sanjiv Lakhia: 20:13
Now there are some other rare conditions that we look at when we're evaluating back pain. Spinal hemorrhaging is one of them. I'm not going to talk too much about that. Other than to say that a traditional non-contrast MRI is the study of choice. If we're looking for hematomas or blood clots, which can develop after let's say procedures. And again, if you want to learn more about spinal procedures, please listen to my interview with Dr. Andrew Sumich where we covered a lot about spinal injections. Osteoporosis is another condition that many individuals suffer with. I see a lot of women and men who come into my office that have evidence of osteoporosis, and I want to talk about that briefly.
Sanjiv Lakhia: 20:55
In particular, when you look at x-ray imaging for osteoporosis, understand the x-rays are not a really good test to look at your bone density, but you can see some secondary signs on x-ray that may suggest you have osteoporosis. And the main one is vertebral fractures or broken bones or slight compression deformities in your vertebral bodies. X-ray will not tell you though, if that's new or old, you have to correlate that with your presentation, with the symptoms and oftentimes further imaging, vertebral fractures are very common if you're on steroids, increasing age and particular female gender have higher incidents and prevalence ranges from around 10 to 24%. And some fractures are very, very painful and others are not. So x-ray again, is the imaging choice that has done initially. But for any lingering concerns, a non-contrast CAT scan is recommended and you also can use an MRI to kind of stage a fracture in terms of acute versus chronic.
Sanjiv Lakhia: 22:00
So that's a pretty good summary there of some of the top spine conditions that cause back pain. And then how we approach them from a system perspective, looking at the proper imaging choice. The other thing I would talk about in particular is the idea of disc herniations and how do you image them? Clearly MRI imaging is the recommended imaging modality. I do hear a lot of patients come in with some misconceptions. You really cannot see a herniated disc on an x-ray. Now, what I would say though, is a plain x-ray can show you evidence that there may be a problem with the disc. You can see the disc space on an x-ray, and that will show you how closely the vertebral bones are approximated. You can see arthritic changes around the vertebral level. You can see bone slippage. Any of these can really be suggestive, that there may be an issue with the disc at that level.
Sanjiv Lakhia: 23:07
There are some situations where the disc will calcify slightly and you can see the slight calcification in the disc space on an x-ray because that's essentially the same substance as bone and give you a really good clue about it. So again, if you're considering or wondering if you have a herniated disc, ultimately you'll end up needing an MRI study to help clarify that.
Sanjiv Lakhia: 23:30
So there you go. I hope that was helpful for you. There's a lot of options out there, a full menu of imaging options from x-rays to MRIs, to CAT scans, bone scans studies, decision making regarding the use of dye and even CT monogram studies, which are a bit more invasive. So at the end of the day, understand that when you present to your doctor with back pain, the key starting point is going to be your history and those red flags that we detailed. If you are not being offered an imaging study initially, normally that's because the probability of a concerning finding on the study is quite low and that you have to go through some conservative care to meet criteria, to qualify for the MRI or the advanced imaging study, at least from an insurance perspective. And take some reassurance that medically you're in a low risk category for having anything serious.
Sanjiv Lakhia: 24:27
Just remember in spite of all the things I discussed today, which are all very concerning from infections to cancer in the spine, osteoporosis, a majority of your episodes of low back pain are going to be self-limiting, they're going to resolve typically within a short period of time and likely not warrant any significant imaging or workup. Once again, this is all just for informational purposes. Only if you are suffering from back pain, please go ahead and see your physician and get care from a qualified professional.
Outro: 25:01
Thank you for listening to this episode of Back Talk Doc, brought to you by Carolina Neurosurgery and Spine Associates, with offices in North and South Carolina. If you'd like to learn more about Dr. Lakhia and treatment options for back issues, go to backtalkdoc.com. We look forward to having you join us for more insights about back pain and spine health on the next episode of Back Talk Doc. Additional information is also available at carolinaneurosurgery.com.
