Spinal (con)Fusion goes International!

Last month I travelled with my colleague and Physician Assistant Jack Bagley to Nepal where I was privileged to be a faculty member for the NZAUSA 2018 Conference on Spinal Deformity.  Several months prior I was introduced to Dr. Chet Sutterlin, a renowned orthopedic spine surgeon who runs a small non-profit called Spinal Health International (SHI).   Through SHI, Chet educates surgeons from developing countries on modern techniques in spinal surgery and NZAUSA 2018 was the most recent iteration of his educational efforts (NZAUSA stands for Nepal, New Zealand, Australia and USA where members of the faculty were from.)   As fellow climbers Chet and I were trading mountaineering stories when he mentioned his course in Nepal.  He’d barely gotten the invitation out of his mouth before I’d accepted! 

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Rather than just performing surgeries in-country via the traditional medical mission model, SHI is unique in its goal of educating the local surgeons so that they can become self-sufficient and build robust surgical programs at home.  It’s the old “teach a man how to fish…” idea.   I hesitate to use the word “educate”, though, because it implies some sort of knowledge gap between the Western surgeons and their Nepali counterparts.  In fact, I quickly learned that these surgeons are quite knowledgeable and skilled and that their only limitations stem from a lack of access to the technological resources we have in the U.S.    

I’ve never participated in an international medical education conference before and I approached my lectures as I would for a meeting back stateside.  Here I was, prepared to talk about advanced minimally-invasive (MIS) techniques such as Lateral ALIF (LALIF) or some of the innovative single-position lateral surgery we’re doing.  Man were these Nepali surgeons gonna be impressed!   As we moved through the Q&A sessions after the first few lectures, though, it was evident that these surgeons weren’t going to find my lectures applicable to their own practices at all!  This was a tremendous oversight on my part, as I didn’t really take the time to understand my audience.  Sure, these surgeons are well-trained, very knowledgable and appreciate the benefits of minimally-invasive single-position surgery in theory. The problem is that they can’t even get the basic retractors used to perform the techniques.  To think they’d be able to replicate these techniques, which are so technology-dependent (and thus very expensive), with the limited resources in Nepal was quite obtuse of me.  In the end I was able to tweak the messaging in my talks to focus more on the general themes rather than the technical nuances of these procedures and I think the talks were well received.  I could definitely tell that the Nepali surgeons are eager to learn more about MIS techniques so that they can start using these techniques in their own practices.  Maybe I’ll be invited back to Nepal for future courses!

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Dr. Thomas presents a lecture to Nepali surgeons on spinopelvic parameters at NZAUSA 2018.

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Jack Bagley, PA-C receives a traditional Nepali hat and scarf as a gift for participating as faculty in NZAUSA 2018. 

Ultimately I was left truly humbled by what the Nepali surgeons are able to accomplish with such limited resources and technology.  They’re routinely tackling complicated pathology such as Pott’s Disease (spinal manifestation of tuberculosis which is rampant in Nepal) and severe spinal deformity using very basic spinal instrumentation.  I was particularly humbled when I was asked to scrub in to a case of a severe thoracic spinal fracture.  I’m supposed to be the “expert” in the room but I looked like a fish out of water performing an open spinal procedure without even a fluoroscope to help place pedicle screws!  I was thoroughly impressed with my Nepali counterpart Dr. Bigyan Bhandari’s skill in navigating this complicated case with his assistant of questionable skill (yours truly) at his side.  Now that I’m back home doing cases in the US, with my advanced instrumentation, image guidance and neuromonitoring technology, I feel like I’m cheating!  Maybe it’s a good thing I’m a surgeon here and not in Nepal!

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Image on left shows severe T12/L1 fracture/dislocation in a young male who was left paralyzed after a motor vehicle collision.  Image on right shows Dr. Thomas and Dr. Bhandari performing an open reduction of the spinal fracture. The accident occurred in a remote part of western Nepal and it took the patient 2 days to get to Kathmandu. 

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The entrance to Grande International Hospital which celebrated its 5th anniversary this year.  This is a very modern private hospital with all of the facilities you’d see in a hospital in the U.S.  The image on the right is a view of Kathmandu taken from the helipad on the roof of Grande.  

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We did get out for some sightseeing!  Image on left is Jack Bagley looking down at Everest base camp on the helicopter flight out of the Khumbu Valley.  Image on right is me standing at Gorak Shep with Pumori in the background.  Mt. Everest would be to my left.  We’re at over 18k feet here and while it may not look like it I feel like I’m about to lose consciousness!

Thanks for reading!

J. Alex Thomas, M.D.

Why patients don’t get better after spinal surgery (it’s not always my fault.)

Ok.  I’m going to admit this for you right here and right now: my patients don’t always get better after surgery.  It’s a crazy thought, I know.  But it’s true.  Despite my best efforts to control all variables to ensure that things go smoothly, things can go awry and the patient doesn’t get better (and sometimes gets worse).  Generally speaking there are two categories of variables that must be managed to ensure success in spine surgery.  First, there are the variables that are dependent on me, the surgeon.  These variables stem from the technical, physical and psychological challenges of spine surgery.  I have to correctly diagnose the patient; I have to know the anatomy and technical nuances of the surgical procedure; I have to plan for the patient-specific anatomy of the case; I have to get a good night sleep before my OR day so that I can focus on the case; I have to maintain a level of fitness in order to handle the physical demands of surgery (yes, spine surgery can be quite physically taxing), etc.  No problem.  This is what I signed up for and I’m up for the challenge.  I can manage these variables better than most.  I do want to say one thing about the psychological stress of these cases.  I want every one of my patients to have the best possible outcome.  That itself weighs on my psyche enough.  But when things don’t go as planned and a patient has a poor outcome (I feel as if I hurt them) it can take months for my conscience and confidence to recover.   This isn’t a therapy session though.  I love what I do and overall I think that I handle the stress of it pretty well (my wife is blocked from posting comments on Spinal (con)Fusion, by the way.) 

Here’s what drives me crazy about taking care of spine patients though.  I can control all of the variables on my end and execute perfectly and the patient STILL doesn’t get better.  There isn’t always a direct correlation with my success in the OR and the patient’s outcome.  Why?  Patient-dependent variables, which often are out of my control, also affect outcomes in spine surgery.   Here, I offer a few of the ways patients don’t hold up their end of the doctor-patient relationship.

1)  Patients don’t want to get better.  Ok, so this is a very broad and potentially very damning characterization of some patients.   You could say obese patients or smokers don’t have the discipline to better themselves and thus don’t want to maximize their chances of success after spinal surgery.  As tempting as it is, though, we can’t blame patients for being obese or for smoking.  Both of these are diseases that many patients are incapable of managing on their own.  So while I do think patients in this country should take more responsibility for their own health, we shouldn’t automatically assume that they don’t want to get better because of their weight or their bad habits.    

What I’m referring to here is a more pernicious subset of patients who are actively trying to not get better, the landmines in the minefield that is my clinic.  These patients usually have some sort of secondary gain that they’re after that leads them to consciously or subconsciously fail to improve after surgery.  Maybe they were injured on the job and want to live off of a worker’s compensation claim.  Maybe they don’t want to be in the military anymore.  Maybe they were in a car accident (not their fault) and their lawyer is telling them they can get more money if they appear more severely injured.  Maybe they want more attention from their spouse.  Maybe they just want oxycodone.  You wouldn’t believe what I’ve seen.   And before you come after me for being insensitive, check the literature.  There are dozens of studies correlating secondary gain with poor outcomes in spine surgery. Thankfully as I’ve moved along in my career I’ve gotten better at spotting patients like these and will avoid ever offering them surgery.  That’s the art of spine surgery.

2)  We aren’t good at accurately measuring if a patient is in fact better.  In spine surgery we rely on patient reported outcomes (PROs) measured before and after surgery to assess the patient’s response to the surgery.    PROs generally fall into two categories: those that measure pain severity and those that measure level of disability.   The visual analog scale (VAS) is the most common tool used to assess a patient’s pain level (see figure 1).  In this scale the patient is asked to rate their back or leg pain on an 11-point scale where 0 is no pain and 10 is the worst pain imaginable.  While VAS is useful on a superficial scale, I find that patients’ responses are widely variable thus making the test unreliable.  I frequently will see that a patient has rated their pain a 10/10 on their intake paperwork but when I walk into the exam room they’re sitting comfortably reading a book.  If this is how the patient self-assesses their pain how can I know for sure that the patient in fact got better?  The problem is that pain is so subjective and influenced by so many factors that it’s just hard to quantify objectively.     

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Figure 1: Visual Analog Scale (VAS) for reporting pain. 

Common measures of disability include the Oswestry Disability Index (ODI) and the Short-Form 36 Health Survey (SF-36).  Both of these are quite thorough but again are subject to variability.  The ODI, for example, asks the patient to rate their quality of sleep, sex life and social life.  In my opinion, these are things that are open to wide interpretation (you ask someone about this stuff on a Friday versus a Monday and the answers may vary!).  With so much variability in patients’ responses on VAS and ODI it can be difficult to determine to what extent the patient actually improved after surgery.  Obviously these PROs leave room for improvement.  These days we’re finding that by combining several PRO modalities we can get a more accurate representation of a patient’s progress.

3)  Patients don’t remember how bad they were and thus don’t realize that in fact they’re better.  Recall bias is a well-known entity in medical research.  When asked to recall facts or conditions in the past, research subjects are notoriously inaccurate.  The same applies to spine patients.  A 2017 study out of the Mayo Clinic found significant limitations in how well patients recalled their preoperative VAS scores when asked to recall them a year later. (Aleem et al, 2017)  Also, more than 40% of patients couldn’t remember if it was their back or leg that hurt them more before surgery.  How can a patient tell me if they’re better after my surgery if they don’t remember what was hurting before the surgery. 

Along the same lines, patients may have improper expectations about their surgery and thus may be disappointed in their outcome even when it’s a good outcome.  For example, often patients with lumbar stenosis and spondylosis present with both back and leg pain.  When I consent them for surgery I explain to them that the minimally-invasive laminectomy that I’m recommending will only relieve their leg pain (by fixing the stenosis) and not their back pain.  Some patients don’t hear that though.  After surgery they’ll come back in and tell me that surgery didn’t help them at all.  The exchange goes something like this:

     Me: “Mr. Smith, you’re two weeks out from your laminectomy.  How’s it going?”

     Mr. Smith: “Horrible.  Surgery didn’t help me doc.  You said you were gonna fix me but I’m no better.”

     Me: “Oh no! Tell me where you hurt?”

     Mr. Smith: “My back hurts, Doc.  You said you were going to help my pain.  What happened?”

     Me: “Well how do your legs feel?  Prior to surgery you told me that you couldn’t even walk to the mailbox because your legs hurt so badly.  

     Mr. Smith: “My legs?  Oh they’re great.  Leg pain was gone when I woke up from surgery.  I walked 2 miles this morning. But my back still hurts.”

     Me: (internally) Sigh

I understand why some patients may not fully absorb what I’m telling them.  They’re scared and distracted when the prospect of surgery becomes a reality.   Prospective patients should be mindful of this, though, and make every effort to listen to and process what their surgeon is telling them.   On my end I’m working on ways to ensure that patients hear what I’m telling them so that they can have accurate expectations about their surgery.  This includes detailed handouts discussing surgery as well as audio/video recordings of preoperative conversations that the patient can refer back to when they’re home with their families.  The most well-informed patients will have the most accurate expectations of surgery and thus are most likely to report that they’re better after surgery.

4)  Patients just don’t get better.  Unfortunately some patients, through no fault of their own or the surgeon, just don’t get better.  As much as we like to think we doctors know everything, we don’t.  I think that we just don’t understand every etiology of back pain.  Is it the degenerated disc?  Is it the facet joint?  Has the brain just learned the pain?  There’s just so much we don’t know.  We do our best to make an accurate diagnosis, assess the patient and prescribe an accurate treatment and yet sometimes even that’s not enough for the patient.  This may be the most frustrating thing about what I do.  All I can do is look at myself in the mirror in the morning and swear that I’m just going to do my best for my patients.  Hopefully it’s enough. 

Ok so maybe there wasn’t much technical information in this post.  That’s OK.  Hopefully by hearing my candid thoughts on the matter you’ll be better equipped when talking to your surgeon about the surgery he’s recommending.  Ultimately I love taking care of my patients and just want them to have the best possible outcome after their surgery.  We’re in it together.  If we both do our parts you, the patient, are going to do fabulously after your surgery.   

 

Thanks for reading!

J. Alex Thomas, M.D.

Sources:

Aleem IS, Duncan J, Ahmed AM, Zarrabian M, Eck J, Rhee J, et al.: Do Lumbar Decompression and Fusion Patients Recall Their Preoperative Status? Spine (Phila Pa 1976) 42:128–134, 2017.

True spinal instability is a clear indication for spinal fusion

As we illustrated in our last post there is a wide spectrum of indications for lumbar spinal fusion.   As you move along this spectrum from unstable to more stable pathology the odds of a successful outcome decrease.  At the far end of the spectrum of diagnoses, the end at which there is a lesser chance of a favorable outcome after fusion, is degenerative disc disease (DDD) and spondylosis (without instability) causing back pain.  In my opinion this is softest indication for spinal fusion.  I’m not saying that you should never perform a spinal fusion on a patient with only DDD, the patient just has to be properly vetted and they must understand that a good outcome isn’t guaranteed in these cases.  On the opposite end of the spectrum is acute spinal instability caused by trauma or some other acutely destructive process such as tumor or infection.  This is the clearest indication for a spinal fusion.  NOTE: we’ve already discussed cervical spinal fusion (ACDF) here and here so this discussion will pertain primarily to the lumbar spine.

Classically, spinal stability is defined as the spine’s ability, under normal physiological loads (“normal” obviously varies widely depending on whether you’re a bank clerk or a mixed martial arts fighter), to a) protect the neural elements (i.e. nerve roots and spinal cord), and b) avoid painful deformity.  Sounds complicated right?  It may be easier to think about what happens when the spine becomes unstable: a) it may not be able to maintain proper alignment and thus may become deformed which causes severe pain; and b) it may not be able to properly protect the spinal cord within which could cause paralysis.  So in a nutshell: a stable spine is one that is protecting you against pain and/or paralysis. 

The concept of traumatic spinal fractures is a vast one that I won’t get into too much here.  Generally, though, fractures are classified as stable or unstable (hopefully you’re starting to pick up on a theme here.)  There are many complicated grading schemes that allow spine surgeons to look at a fracture on imaging and determine if it’s unstable or not.  One classic scheme is that of Denis which divides the spine into three columns.  Stable fractures typically only involve one column of the spine. Examples of stable fractures include fractures of the spinous process (a so-called clay shoveler’s fracture, see Figure 2), compression fractures and transverse process fractures.  Stable fractures may be painful from the local trauma of the injury but they do not cause painful deformity nor do they threaten the spinal cord or nerve roots.  Thus these types of fractures may be treated conservatively such as with bracing. 

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Figure 1: Illustration from Denis’ 1983 paper discussing his three spinal columns and their involvement in traumatic injuries.

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Figure 2: Fracture of the C6 spinous process (clay shoveler’s fracture).  Source: https://radiopaedia.org/images/3175670

Generally speaking if two or more of Denis’ columns are involved in a fracture it is considered unstable (again let me reiterate that Denis’ model is quite simplistic and analyzing a fracture isn’t always as easy as looking at the spine in only 3 columns.)  When a fracture is determined to be unstable a spinal fusion may be indicated to restore stability.  If an unstable fracture is left to heal without surgery it may heal poorly resulting in a painful deformity. Worse, if a patient with an unstable fracture is allowed to get up out of bed and loads their spine the fracture may shift resulting in injury to the spinal cord and paralysis. 

Trauma isn’t the only cause of acute spinal instability.  Indeed, aggressive tumors or infections can destroy the integrity of the spine thereby causing painful spinal deformity and perhaps paralysis.  These lesions are treated in a similar manner as acute fractures depending on which part of the spinal column has been damaged. The case presentation below describes a case I had a few years ago of an elderly gentleman with severe damage to his spine caused by a staph infection. 

Generally speaking when deciding which type of spinal fusion to perform for acute spinal instability, I’ll go to where the problem is:  if the pathology primarily involves the vertebral body in front of the spine, for example, I’ll do a corpectomy to remove the fractured vertebral body.  Once the body is removed I’ll reconstruct the spine with a spacer inserted where the damaged vertebral body was, and a combination of plating or screws to provide extra stability (we’ll talk about these devices in more detail in future posts.)  The main goal of all of that surgery is to promote new bone growth across the damaged segment of the spine.  It’s this new bone growth that restores spinal stability.  

CASE PRESENTATION:

The patient is a 75yo male with methicillin-resistant staph aureus (MRSA) bacteremia (in his bloodstream) who presents with worsening mid-back pain.  Imaging reveals T11-12 discitis.  (Discitis is an infection of the intervertebral disc space that is probably the most painful condition that I see.  You can usually make the diagnosis by very gently bumping the patient’s bed when you approach the bedside; if the patient screams out in pain it’s probably discitis.  That’s how bad it is.)  The medicine doctors tried a long course of antibiotics but unfortunately his pain didn’t improve.  Repeat imaging revealed that the infection hadn’t been cleared and in fact had caused further destruction of the T11 and T12 vertebral bodies (see Figure 3.) This destruction resulted in spinal instability and kyphosis (a painful deformity in which the spine falls forward.)  

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Figure 3: CT scan illustrating T11-12 discitis resulting in severe bony destruction (red arrow) and resultant kyphotic deformity (blue arrow indicates top of spine falling forward). 

When I met this patient he looked like he had given up and wanted to die.  He’d been bedbound from his infection for weeks and now was quite debilitated.  He agreed to undergo surgery and underwent a T11 and T12 corpectomy (via a lateral approach through the chest and behind the lung) followed by reconstruction of the spine with an expandable cage and percutaneous pedicle screws (see Figure 4.)  By one month post-op the patient reported no pain and was walking without assistance.  The last time I saw him about a year after his surgery he was living a normal life at home with his family.  He looked like he’d been given a new chance at life. 

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Figure 4: Postoperative AP (left) and lateral (right) X-rays with expandable corpectomy spacer at T11-12 (red arrow) and percutaneous pedicle screws from T9-L2 (blue arrows).

I think I’ll spend the next post or two talking about the various forms of spinal implants that we use to achieve a spinal fusion. I had planned to do this later but I think that by presenting it first it will help you better understand the various spinal fusion procedures discussed in later posts. 

 Thanks for reading!

 J. Alex Thomas, M.D.

Sources 

Denis F: The three column spine and its significance in the classification of acute thoracolumbar spinal injuries. Spine (Phila Pa 1976) 8:817–31, 1983.

What makes a far lateral disc herniation unique (and PAINFUL)?

We made an important distinction in the last post: that of the far lateral disc herniation.  We’ve just discussed the more common central herniated nucleus pulposus (HNP) in which the disc herniates into the center of the spinal canal (see figure 3 of this post.)  This centrally herniated fragment hits the traversing nerve that is still within the spinal canal (e.g. a central L4/5 disc herniation causes a radiculopathy of the L5 nerve.)  In a far lateral HNP, occurring only in about 10% of cases, the piece of disc herniates on the side of the spine and compresses the nerve along its course within the neural foramen as it exits the spine (e.g. a far lateral L4/5 disc causes a radiculopathy of the L4 nerve.)   See figure 1 for an MRI showing a far lateral HNP. 

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Figure 1: Axial MRI showing large right far lateral HNP (outlined in pink.)  Note the displaced nerve root (pink arrow) as compared to the normal nerve root free in its neural foramen (green arrow). 

Often I can identify a patient with a far lateral HNP right when I enter the room because they’re MISERABLE.  The pain associated with far lateral HNPs is typically much worse than that seen with central HNPs.  Just as it exits from within the neural foramen, the nerve dilates into an important junction point called the dorsal root ganglion (DRG).  It’s this exquisitely sensitive part of the nerve that is compressed by a far lateral HNP.  Couple that with the fact there’s a very limited amount of space within the bony neural foramen for both the herniated disc fragment and the DRG and one understands why this type of disc herniation is so debilitating (see figure 2).

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Figure 2: Image of the right side of the lumbar spine showing the nerve roots exiting via the bony neural foramina.  Note the dilation of the DRG within the confines of the foramen (red arrow.)  

A far lateral HNP requires a different approach than the standard discectomy we discussed in the last post.  In the far lateral discectomy, I’ll typically employ an “outside-in” approach to find the fragment under the nerve as it exits the foramen.  First, the incision for a far lateral discectomy is made a few more centimeters off of midline compared to that of a standard discectomy.  Next, I’ll dock a tubular retractor in between the transverse processes at the level in question (see figure 3).  I’ll then work my way into the foramen and look for exiting nerve within the soft tissue of the intertransverse space.  One benefit of using an outside-in approach is that usually I don’t have to drill away any of the facet joint and avoid potentially destabilizing the spine.  Once I’ve found the nerve (the DRG is usually what I see first) I move it out of the way and the piece of herniated typically found right underneath.  In order to mitigate some of the pain caused by my manipulation of the DRG I will apply some steroids to the nerve when I’m done removing the disc.

Discectomy docking points

Figure 3: Image depicting the docking points for discectomy in relation to bony anatomy at the right L4/5 level. The blue circle illustrates the docking point for the tubular retractor in a standard central discectomy.  The green circle illustrates the docking point for a far lateral discectomy. 

Recovery from far lateral discectomies is typically rougher than after standard discectomies.  The DRG is already inflamed and manipulating it to get to the herniated fragment can often make the patient’s pain and numbness worse before it gets better.  Thus, I always have to get my patients with far lateral HNP mentally prepared for a tough couple of weeks after their discectomy.  In the end, though, patients do very well after a far lateral discectomy. 

Thanks for reading!

J. Alex Thomas, M.D.