fbpx

Location

Great Falls, Montana

Email Us

hello@acrossthecontinuum.com

Follow us :

Issue 2

Table of Contents

Want to download the PDF?

To what extent are surgery and invasive procedures effective beyond a placebo response? A systematic review with meta-analysis of randomized, sham controlled trials

Dr. Joe Camoratto PT, DPT

Key takeaways:
  • Even if physical therapy or rehabilitation doesn’t get the patient where they, or you, had expected it would, doesn’t mean surgery is the next step.
  • If non specific effects make up the majority of the effects of surgical interventions, maybe we need to reflect on how we are communicating and interacting with our patients.
  • We can now conclude that at least chronic pain conditions lack clear evidence for the efficacy of the explored surgical interventions

Hello and welcome back to the Across The Continuum Research Review!

This is issue 2 and we are going to be discussing a lot of cool things regarding placebo/contextual effects, chronic pain and surgery! All things that most of us in the rehabilitation field see on an extremely regular basis. We hope that the takeaways from this review will not only help with clinical decision making when patients or athletes are considering surgery, but also the three topics in and of themselves applied to other contexts, as best as they can be.

The Problem

We are facing a growing issue in the medical world. There is an increase in surgical procedures and a paucity of studies comparing them to sham to evaluate specific and non specific effects. The classic scapegoat is that “it just makes sense to do it” and so science unfortunately seems to take a back seat to bias filled opinions. What we know about pain, placebo and expectations lead us down the road of questioning the specific and non specific effects of surgery and thats just what this paper looks at.

The reason the “it just makes sense” intuition is such an issue is that there are far too many moving parts within something as complicated as the human symptom, let alone surgery, contextual effects, prior experiences and beliefs to just assume things, which is why we have science to step in.

Definitions

We have 3 definitions that we should get out of the way before starting into the meat and potatoes, just so that we can all be on the same page as we go over the two papers for today. Placebo or contextual effects is first on the list. Our first paper, To what extent are surgery and invasive procedures effective beyond a placebo response? A systematic review with meta-analysis of randomized, sham controlled trials, defines them as:

“The observed outcome changes in the sham groups. These changes are due to the natural history of the patient’s condition or regression to the mean and a response to the ritual of medical treatments.”

There are a few other definitions that come out of this one that we should pick into while we are at it. Sham is essentially a fake version of an intervention. Doing all of the steps that would be included in that intervention without actually delivering the “good stuff”.

Natural history is the progression of a disease or condition over time. Lucky for us clinicians, most MSK conditions naturally improve as time ticks away.

Regression to the mean is a statistical term that if one sample of a random variable is extreme, the next sampling of the same random variable is likely to be closer to its mean.

Consider this in the context of symptoms where the presence of symptoms are the extreme and the mean is a baseline the person was at before the onset of these symptoms. The second big definition that we have to go over there is chronic. Chronic pain is very usually defined as pain that has been lasting longer than 3 months. Now we could open up a whole other can of worms regarding this definition itself, but we wont, for time sake.

Last, this paper defines a couple different types of surgery:

  • Classical surgery was defined as a procedure that followed the typical surgical experience that uses preoperative preparation, anesthesia, an incisional trauma (usually through muscle and fascia and into the peritoneum) and a postoperative recovery process
  • Invasive procedures were defined as when an instrument was inserted into the body (either endoscopically or percutaneously) for the purpose of manipulating tissue or changing anatomy.

The Questions

So now that we have our paper introduced, and the definitions that are the most important currently defined, let’s dive into it. This paper is asking some large and challenging questions to start. Just from the title we can see that it is challenging a huge aspect of MSK health.

This is the one weird paper that most orthopedic surgeons DON’T want you to know about.

The first question it is asking is, what is the quality and quantity of research that compares surgical intervention to sham procedures? The subquestion that we can pull form this one is, have these procedures been compared to tricking the patient into thinking the procedure was done? The answer to this question can tell us a lot about what really gets the patient “better” and how we can move forward in implementation of these procedures.

The second question is, can we estimate the magnitude of the specific effects of these procedures over the sham procedures? Essentially, does the thing the procedure is intervening on drive the outcome that the patient is experiencing, or is it more the act of undergoing the procedure itself the thing that helps? More on this later.

The third question is, can we estimate the magnitude of the surgical ritual and the non specific effects of the procedure on these outcomes? Also put, can we determine how much of the “show” surrounding the procedure influences the outcome?

Pain

The current model of pain is constantly being updated and attempted to move forward by the scientific community. Currently we are trying to leave behind the biomedical model of pain, which attaches some sort of abnormality in the human system (torn tendon, degenerate surface, disc changes etc) to each and every symptom that is presented by the patient, at least in the MSK world. Why are we leaving this behind?

Well, because we know two things (at least): people can have structural abnormalities like those things listed above, without having any symptoms at all, and people can also have symptoms without having any changes at all. This begs the question of what sort of relationship do the two really have. As we move away from the “pain generator” way of thinking in the biomedical model of pain, we start to move into the biopsychosocial model of pain, which looks at the entire human as a whole, as you can intuit from the name.

Unfortunately, the reason that we even need a paper like this one seems to be at least partly because we as a medical community are still trying to alter the body to fix symptoms.

But Joe, if someone ruptures their ACL, they have an inflammatory process that involves things like pain, swelling, bruising, redness and heat.

Yes, dear reader, that is very true. Let’s briefly look at the different stages of healing that we touched on early when discussing the timing of chronic pain. Now, depending on where you look, there will be different timelines and ways to describe these as well as overlap in timing.

We have the Acute (1-30 days) the subacute (30 days to 90 days) and the chronic (90 days and on).

The point of this quite brief review is this: after we get about 90+ days away from an injury, we can safely assume that the body has done a fantastic job of managing the inflammatory response that will have been produced and that the person is well on their way of following the natural history and regression to the mean of their situation. We know that pain that persists past this time is less so related to the active structural deviation incurred and likely more so moving into something of a pain or symptom issue in itself.

We start to worry less about the “pain generator as we discussed earlier. Which brings us back around to the question posed above. Where does surgery that seems to connect the structural deviations found on imaging or incurred during an injury sometimes years ago to the symptoms currently presenting fit?

Contextual Effects

One topic that is gaining speed in the MSK and general medical world is something call contextual effects. Simply, what is the context of the situation? What does the facility look like? New or old? Is there soft music playing or is Shrek 3 on the TV? Does the provider have Lulu lemon joggers on or pleated pants and a white coat? Is it in a nice part of town? What sort of intervention is being performed? Is it invasive or not? Does it match the patients expectation or belief about what should be happening? Do they have buy in? All of these things are part of the context and can and do contribute to the contextual effects.

Contextual effects can improve or detract from the experience. Certainly we can all imagine scenarios for either. This discussion is very relevant to our surgical discussion currently as you can imagine that they show is much different for a total knee replacement than it is for a conservative care session. Being prepped for the OR and being put under are much more involved and intense that performing LAQs on the edge of a plinth. Watching a needle go into your knee and seeing fluid administered directly into the joint is much different than receiving reassuring words from your PT.

Lastly, knowing that they directly intervened on the “bad part” that was “causing the pain” is much different that being told that the MRI findings don’t predict your symptoms. Two different context and two different outcomes. So why the big push with figuring out what a contextual effect is? Well the paper currently is trying to figure out if the outcomes that these procedures are achieving are from the non specific or contextual effects of the show or from the specific effects of the surgery (ex. you have less bone underneath your acromion, thus that is the reason you feel better).

As we reviewed earlier, there is a big issue with the medical world just accepting surgeries because they make sense, without bothering to test if they are better than the sham! Why is this an issue? There are harms, high costs and unknowns associated with surgeries, and if they are only due to the show, then we need to figure out a safer and more cost effective way of getting people to the end goal. There were a number of types of surgeries and procedures that this paper looked at including: low back pain (most frequent pain related), arthritis, endometriosis, Parkinson’s disease, obesity (most frequent non pain related), migraines, angina, abdominal pain and gastro-esophageal reflux.

As mentioned in the discussion, no specific effects accounted for not only a majority of the effects, but well over half of the effects seen when compared to sham:

“While non-specific effects accounted for approximately 65% of the effects from all invasive procedures, they made up to 78% of the active treatment effects in chronic pain conditions and 71% of the active treatment effects in obesity.”

A couple of notable quotes to keep in the forefront of your brain:

“Our subgroup analyses indicate that the current evidence does not support the specific efficacy of invasive procedures for chronic pain conditions (p=0.08) and was borderline for obesity (p=0.05), but does support these procedures for GERD”

“We can now conclude that at least chronic pain conditions lack clear evidence for the efficacy of the explored surgical interventions (eg, classic surgery and endoscopic procedures.”

“The evidence from available sham- controlled trials indicates that invasive procedures are not clearly more effective than sham procedures for various chronic pain conditions including endometriosis, back pain, arthritis, angina and migraine”

Wrap Up

The take home message is this: even if physical therapy or rehabilitation doesn’t get the patient where they, or you, had expected it would, doesn’t mean surgery is the next step. Consider the harms and unexpected outcomes of surgery as well as the information presented here in this paper. If non specific effects make up the majority of the effects of surgical interventions, maybe we need to reflect on how we are communicating and interacting with our patients. That being said, unfortunately there is only so much we can do when conservative care isn’t working how we anticipate. This review isn’t attempting to sew mistrust in the surgical system, but there certainly needs to be more rigorous science and less certainty than is currently held.

The answer is not to undermine surgery in the face of unsuccessful rehabilitation, but to have honest conversations and answer questions as openly as possible. A worst case scenario here would be to undermine surgery, just to have someone not succeed with conservative care and end up on an operating table, having you, one of their medical authority figures having nocebo’d them for 16 weeks.

 

References:
  1. Jonas WB, Crawford C, Colloca L, et al. To what extent are surgery and invasive procedures effective beyond a placebo response? A systematic review with meta-analysis of randomised, sham controlled trials. BMJ Open 2015;5: e009655. doi:10.1136/ bmjopen-2015-009655

 

Surgery for chronic musculoskeletal pain: the question of evidence

Dr. Joe Camoratto PT, DPT

Key takeaways:
  • As we get further and further away from an injury or a structural change, things get fuzzier and fuzzier regarding things like “root causes” or “pain generators”
  • None of the studies that used patient blinding for any procedure found the procedure to be significantly better than not performing the procedure.
  • The system we have has its flaws, but it is the best that we have and does a significantly better job than those who claim to be arbiters of the truth without having actually done any of the legwork

 

Just like some wines are paired with chocolates, this first paper pairs amazingly with the second one. While we are on the topic of surgery, chronic pain and placebo effects, why not introduce you to the scientific stylings of Dr. Ian Harris. Not only does he have a great accent, but he has written a book and spoken a whole lot on the topic of surgery and placebo. This paper kicks off outlining the most common indications for surgery. Those indications are related to the musculoskeletal system, mainly unintentional injuries and musculoskeletal disorders. Among these disorders are arthritis and low back or neck pain.

As you’ll remember from the previous study, low back pain and arthritis were also among the other conditions that contained very few sham studies regarding surgical intervention. Im so glad that were were able to get those chronic pain and placebo definitions out of the way so that we need not go over them again in depth. Dr. Harris and his friends go on into the second paragraph of this article underlining the usual attribution of pain is to visible changes on imaging or objectively measurable mechanistic rationals (degenerative joints, torn tendons etc). They make sure to very specifically state this ignores the complex nature of chronic pain.

We can recall from the previous paper that as we get further and further away from an injury or a structural change, that things get fuzzier and fuzzier regarding things like “root causes” or “pain generators” (not that they were clear cut to begin with). The importance of the scientific method thankfully shines through once again in this paper, first undermining what called observational evidence (I saw it work so it must be this way), and calling on the scientific community to produce more Randomized Controlled Trials to aid in inching us closer to what is “true”.

For those who don’t know, a randomized controlled trial is a study that randomly assigns two similar groups into two separate groups. Those ground would usually be an intervention and a control group. The intervention group get the intervention, and the control group gets nothing. There can also be a sham group like the previous article looked at, in which they do everything except for the actually tissue manipulation or what have you.

The participants are blinded to which group they are in, meaning that they don’t know what groups they are in. This ensures that they cannot be influenced by their expectations of how they should react. Sometimes they will even use a double blinded method, meaning that the participants AND the researchers are unsure what group the participants are. This can help to keep the researchers from unknowingly altering the way that they interact with the test participants (no one winking at those who are getting the intervention or anything).

Why go to such lengths to build robust scientific methodology? First of all, we are FULL of biases. You might not feel them while you are interacting with your reality, but your observation is rife with biased views of the world. They stem from how you were raised to how you were taught, how past interactions went and what part of the world you were raised in. In fact there are 188 cognitive biases that we know about.

The whole point of the scientific method is to try and dampen or totally remove these biases from our testing processes so that we can see whats left. Thats why when you hear clinicians say things like, “I’ve seen it work” or “what I do is ahead of the research” or “this is the real world and not the lab”, you should cringe. They likely don’t agree with what the current evidence base has to say and thus turn away from it. Also know as confirmation bias!

Turning back to the paper, they build a list of 14 procedures that they evaluate the current research body for.

  • Knee arthroscopic meniscectomy,
  • Knee arthroscopic debridement for osteoarthritis
  • Total knee arthroplasty (TKA) for osteoarthritis
  • Total hip arthroplasty (THA) for osteoarthritis
  • Shoulder arthroscopic subacromial decompression,
  • Shoulder arthroscopic clavicle/ acromioclavicular joint excision,
  • Shoulder rotator cuff repair,
  • High tibial osteotomy (HTO),
  • Carpal tunnel decompression,
  • Spine disc replacement,
  • Spine fusion for pain,
  • Lumbar laminectomy for lumbar spine stenosis
  • Ankle arthroscopy
  • Elective total shoulder arthroplasty

 

After sifting through 6734 individual studies, they found that 64 of the them were RCTs and compared the procedure to not performing the procedure. Less than 1%. Of that less than 1%, nine of them (14%) were favorable to surgery.

“None of the studies that used patient blinding for any procedure found the procedure to be significantly better than not performing the procedure.”

So what Joe? The patients got better. Whats the big deal?

Yes, we are very happy that the patient had their desired outcome, but don’t forget about the big issues with this argument that we outlined in the previous article.

  • There is a non zero risk of harm associated with surgical intervention. From infection and rashes all the way to death. (“sorry that your loved one died from a surgery that was shown to be no better than us doing nothing, but it seemed like a good idea at the time and the theory just made sense”)
  • There is a high cost to these surgeries
  • If we find that these surgeries are no better than the sham or no surgery at all, why would we expose anyone to 1 and 2?

 

This paper is short and sweet. Its got a concise message and its made very well. It is a personal favorite of those who find themselves in the medical conservative group. Just to continue to pile on, let’s review some of the reasons that people may AVOID doing to proper science in the face of surgery.

  1. “lack of any incentive to perform them”
    1. It is just plain difficult to run RCTs when it comes to surgical interventions
  2. “the lack of trial infrastructure and expertise in trial research”
    1. It is difficult to become someone who is even able to conduct this type of research
  3. “a lack of equipoise”
    1. Equipoise is the idea that a clinician truly doesn’t value one intervention over another. When conducting an RCT, or any science for that matter, the goal is to avoid bias, and if the researchers don’t show clinical equipoise then they are biased from the start.
  4. Some procedures are perceived to be so effective that the parachute analogy is often invoked
    1. The parachute analogy seems to be a smoke and mirrors argument for surgeries that make so much sense that they don’t even need scientific testing:
      1. “since parachutes were never tested and work, medical interventions that have face validity (“it makes sense”) are also likely to be effective and should be used without trials.”
  5. “It may be argued that some of the surgical procedures in this analysis do not require RCT evidence; such an argument has been made for THA, and this procedure had no suitable comparative trials included in this study. However, the facts that most of the included procedures had been subjected to comparative trials, that most of those trials found them to be ineffective, and that previous claims of overwhelming effectiveness have often been shown to be wrong suggest that such evidence is required and that such effectiveness should not be assumed”

It is supremely easy to try to make logical sense of complex systems like the human organism. A + B must = C and so I’m just not even going to look into it. This is a method for disaster and this paper, as well as the previous one, should be more than enough to make any alterations to your common sense thinking machine toward leaning on scientific scrutiny. The system we have has its flaws. It is slow, it can’t account for each and every scenario that will occur, and it has much bias, BUT it is the best that we have and does a significantly better job than those who claim to be arbiters of the truth without having actually done any of the legwork.

 

References: