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Call a spade a spade

  1. “Although numerous propositions have been put forward in the literature about how we might usefully subclassify low back pain (LBP), we must first consider the potential utility and futility of such aspirations and ask, “Will it change the outcomes of patients?”

 

This first statement in the paper is great. All therapist classify patients using either a sophisticated method (which will be spoken of in this paper) or a method that lacks sophistication (a patient’s education level, income level, etc). The big question that we have to ask is “does any of it really matter”.

 

  1. “Within this arena, there are two schools of though-nominalist and essentialist. Nominalists define a disease by its symptom profile (CLBP = back pain of duration > 3 months). Essentialists state that each specific disease has an underlying pathophysiology, implying treatment of the disease requires treatment of the pathology”

 

This is fun for me to read. I never though of it this way, but I guess that I would be a nominalist in most cases. Rarely do I believe that the underlying pathophysiology must be treated in order to resolve symptoms. Let me give you an example. For patients that have degenerative disc disease (this is a very common diagnosis in the clinic and most will have this over the course of the lifetime) there is nothing that I will do to regenerate the disc, but I may be able to teach the patient how to either shut off the pain or manage the pain. This would be the nominalist in me. The essentialist in me has another example, which is also a real example in the clinic. There was a patient coming to therapy for treatment of his shoulder. In the process of treating the shoulder he developed back pain (not while in the clinic with me). Anyway, he neglected to tell me about the back pain, but later in the course of care (all within a couple of weeks) went to an urologist for urinary issues. He never told his urologist about the back pain and was advised to use a catheter to urinate! Anyway, he told me about his catheter issues and I was curious. I asked if he was experiencing any back pain or leg pain and sure enough he was. I called a surgeon that I trust and the patient was in surgery within a day. He had an issue that required surgical correction of a pathological issue. In this case, I am an essentialist. Now that I think about it, I am not sure if one can root for only one team.

 

  1. “These classifications can broadly be divided into three groups: (1) those that consider clinical descriptors, (2) those that describe prognosis, and (3) those that consider response to treatment.”

 

I am credentialed in Mechanical Diagnosis and Therapy, formerly known as the McKenzie Method. In this respect I am a little biased and it is important that you guys know that I am biased towards one method before reading the rest of the article. MDT would be a patient response approach.

 

Other systems, such as the Treatment Based Classification System (TBCS), which wasn’t even considered in this article it looks like, is a system that is based on clinical prediction rules. This means that if you come in and say some key words and test positive on some key tests that it would dictate a specific category of treatment, which is completely different from a patient that speaks of different key words and test negative on key tests.

 

  1. “We identified 28 classification systems of CLBP (chronic low back pain)…systems that described subclasses based on pathoanatomy, pahtophysiology, or clinical signs and symptoms without attempting to predict outcome or direct treatment were labeled as ‘diagnostic’…systems attempting to predict outcome irrespective of treatment were termed ‘prognostic’…systems that suggested treatments for different subclasses were termed ‘treatment based’…16 diagnostic, seven prognostic, and five treatment-based classification systems for CLBP.”

 

Typically, when I am writing a blog post I go to the back of my library (actually a trunk in the crawlspace) and grab an article that I read years ago. (I know…I am a nerd because I keep research articles that I read years ago). Anyway, re-reading the highlights of this article is like reading the article for the first time. I forgot that there were this many classification systems out there. Typically only a few are spoken of in the clinic and these are: the movement impairment system, Quebec Task Force, Mechanical Diagnosis and Therapy, Treatment Based Classification System and the Canadian Back Institute Classification System.

 

I will have to read the highlights of the article again in order to figure out which system fits into which category.

 

  1. “The first description of a treatment based system was by McKenzie, who classified patients into three main syndromes based on physical signs, symptom behavior, and their relations to end-range lumbar test movements”

 

Is it wrong that I was pounding my chest when I was typing the above sentence? This reminds me that I will have to write a blog on the history of MDT. One can see the history of MDT in the book Against the Tide.

 

  1. “Riddle and Rothstein assessed 49 physical therapists with varying clinical experience, in their ability to classify 363 patients according to the McKenzie system. Their ability to agree at the subsyndrome level was poor…Agreement among examiners was only marginally improved for classification into the three main syndromes…Agreement among examiners was better in three studies that assessed physical therapists who completed a certification in the McKenzie method with percent agreement ranging from 74% to 91% for subsyndromes and 93% to 100% for main syndromes.”

 

This tells us a few things. First is that those certified in using a method are actually good at using the method and those that aren’t certified aren’t as good at using a method. I think that this thought process would hold true for many aspects of different professions. I actually had a discussion on FB about this topic and I don’t think that it is the magic of the certification that increases agreement, but the hours upon hours of studying that went into preparation for the test that increases therapist’s competency of using a method. When a therapist is certified though, the agreement is close to perfect.

 

  1. “Movement System Impairment classification…proposed by Van Dillen et al and includes five categories based on signs and symptoms elicited with direction-specific tests in the direction of lumbar flexion, extension, rotation, rotation with flexion, or rotation with extension…shown to be reliable in three different studies”

 

I’ll have to read more about this system because at a glance it sounds eerily similar to McKenzie’s method. Both appear to have a “directional preference” based treatment and avoidance (I’ll assume only temporarily) of the aggravating factors.

 

  1. “Canadian Back Institute Classification system…recognition of syndromes or patterns of pain with no direct reference to pathoanatomy…the classification was based on the location of dominant pain, whether the pain was constant or intermittent, and which movements or postures exacerbated or alleviated the symptoms…shown to be reliable in one study.”

 

Again…these systems are starting to sound familiar and similar to each other. Figure out the symptom location, what makes them worse, what makes them better, is it mechanical or chemical and then name it for what it is. This appears to be the same in the three classification systems.

 

  1. “Movement and Motor Control Impairment (MCI) classification system by O’Sullivan proposed treatment based on subgroups of patients with CLBP categorized by five distinct patterns based on a specific direction of MCI…flive categories included flexion pattern (loss of motor control into trunk flexion resulting in excessive abnormal flexion strain), flexion/lateral shifting pattern (MCI around the lumbar spine with a tendency to flex and laterally shift at the symptomatic segment), active extension pattern (MCI around the lumbar spine with a tendency to hold the lumbar spine actively into extension), passive extension pattern (loss of lumbar motor control around the lumbar spine with a tendency to passively overextend at the symptomatic segment), and multidirectional pattern (MCI around the lumbar spine in multiple directions)…The percent agreement was 70%.”

 

It seems like this system is all about a loss of control at the lumbar spine. The agreement of classification isn’t bad at 70%. I struggle with this system because it does not appear to be a patient response based system. I’ll have to read more into this system. The first thing that I think of is “how do we know if we are doing the right thing and how long do we have to wait in order to determine if we are moving in the right category.

 

  1. “An RCT assessed the classification system by McKenzie by randomizing 260 patients into two groups: Group A was treated with the McKenzie method, and group B was treated with intensive dynamic strengthening training…tendency toward a difference in reduction of disability using the Low Back Pain Rating Scale in favor of the McKenzie group at the 2-month follow-up assessment, but no differences at the end of treatment (4 months) and at the 8-month follow-up evaluation.”

 

Some would look at this and say that MDT was no better than strengthening at 4 and 8 months. Others would look at it and say that MDT was better than strengthening at 2 months. If you were a patient, which would you rather have? Would you rather be better at 4 months or two months…knowing that you would be at the same place in 8-months? This study doesn’t seem too realistic in that once a patient is improved with MDT, then the treatment would transition towards a functional strengthening phase.

 

  1. “…overall strength of evidence …is High for the McKenzie and Movement Impairment Classification systems, especially when examiners have been extensively trained; Insufficient for the Canadian Back Institute Classification; and Moderate for the MCI Classification”

 

This sentence sums it up. MDT has moderate evidence to support that it is highly reliable. The Canadian Back Institute Classification system has low evidence to show that it is insufficiently reliable.

 

If I were a therapist going to learn a new method, I would have to start with MDT based on the volume of studies demonstrating reliability.

 

  1. “Once it is established that patients can be classified reliably, it then must be demonstrated that by directing a specific treatment at the subgroup, one can expect an improvement in treatment outcomes.”

 

This means that once we know what we are seeing…can we fix what we see? What is the purpose of classifying a patient into a group if the treatment for that group is ineffective?

 

  1. “This suggests that the ideal classification system should minimize the number of subgroups to ensure that the user can become confident (and competent) it its use with little training.”

 

Holy smoly do I disagree. We just said that the subgroups must lead to a specific treatment that performs better than other forms of treatment. If we minimize the number of subgroups, then we are minimizing the impact of subgrouping. For instance, if we state that there is only one subgroup, then what is the likelihood of the treatment for that one subgroup helping all of the patients? We already know that it’s pretty low…this is how we got into this mess to begin with. In the past, all low back pain was treated very similarly, with horrible effects. Now, if there is only one subgroup, we can be assured that most people would fit into this subgroup. Therefore, the therapists would be highly reliable in choosing the group in which to place the patient. THIS DOESN’T MEAN THAT IT WILL ACTUALLY BE EFFECTIVE TREATMENT!

Back pain is very costly in the US. We need to do a better job of minimizing the disability from LBP and educating the patients regarding back pain natural course and how to live and manage this ailment. There have been other systems created since this article was published in 2011 and we will see how these systems fair over time.

Excerpts from:

Fairbank J, Gwilym SE, France JC, et al. The Role of Classification of Chronic Low Back Pain. Spine. 2011;36(215):519-542.

 

link to article

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