🦀 Issue 150 - Can you actually tell?

In the world of outpatient ortho PT, we spend a lot of time pushing on people’s backs. I do very little manual therapy and even I spend a fair bit of time pushing on backs. In school (which already feels like quite a while ago) we learned about feeling for hypomobile and hypermobile segments. But like, is that possible?

I know last week we talked about what we kinda don’t know. This continues that theme. But instead of things we don’t know about from research, we’re talking about things our hands don’t quite know. We’re going to look into a narrative review from a few years ago, about the clinical value of the practice at all. King Crab supporters also learned more, as usual. For them, I dove into a systematic review of whether or not it works at all, and lastly we’ll discussed whether what we feel actually lines up with what our instruments can tell us. It’s a mosey on down the spine and it starts right now.

Here are some general thoughts

The Gist - This narrative review from PM&R looked into “manual segmental spinal assessment” AKA, pushing on people’s backs, to see what we actually know about it. Picture a patient lying prone as you apply gentle pressure along their spine, attempting to gauge resistance. Sounds familiar, right? Idk about you, but I know that MSSA involves two primary techniques: the pisiform and thumb-tip methods. For me, thumb-tip is usually the first pass (especially on an anxious patient) while pisiform is later. The pisiform technique employs the ulnar aspect of your hand, while the thumb-tip method utilizes (well, duh) your thumb tips. By gauging resistance, we determine spinal stiffness, with higher resistance indicating hypomobility and lower resistance suggesting hypermobility. At least, in theory.

I say in theory because previous research has raised eyebrows about its reliability, both within and between practitioners. Quite a few studies have reported low reliability, suggesting that our assessments may not be as consistent as we'd like. This inconsistency could be attributed to several factors, including variations in visual occlusion, loading frequency, table surface, patient body habitus, trunk muscle activity, intra-abdominal pressure, and more. But it is important to know that the inconsistency is extreme. Only 7-12.5% of studies included in another review displayed reliability that qualified as “acceptable”.

So let’s standardize things a bit. They cite research that showed consistent loading speed and frequency (via a metronome) and consistent technique are big helps. They also recommended resetting your force via a reference force (maybe on a scale?) to standardize things. Using this method brings inter-rater reliability up to a good level.

The more difficult things to standardize are your patients. Having intentionally relaxed trunk muscles is a big help, and is having patients hold their breath at their functional residual capacities, that is, have them breath out and hold.

And if you’re one of those clinics that has multiple tables from multiple brands, you’re gonna wanna use the same ones over and over to be more accurate. Switching from a rigid table to a padded one has been shown to significantly decrease spinal stiffness assessments.

Tell Me More - There are other ways to do this though. Ways that do work better. But they’re not free. And that’s sad. And I’m not really going to get into them because you obviously don’t have one and if you do have one you don’t need me to tell you how it works. Instead, let’s talk a bit about if it matters at all before we talk about if it matters at all.

According to this paper, we just don’t really know. People with LBP may have greater than average spinal stiffness, but it’s inconsistent and since we don’t actually know if our testing of spinal stiffness is very good, it’s not a good metric. One small study showed that men with LBP did have stiffer backs than women with it, but it only had 67 people in it, so it was quite small indeed. Add in the fact that what you call hypomobile I may call normal and vice versa and we’re in trouble. It does look like stiffness decreases as pain decreases, but only by about 10% and that may not even be detectable by the methods we use.

And if you (like me, if I’m being honest) read through this whole piece and still think “well sure, but I’m different, I’m good at this, I know what I’m doing.” You probably don’t. 50% of people are below average. You’re not one of them, obviously. But the point exists that it’s odds on you’re similar to the PTs who undertook these studies to give us these results. I am definitely not saying that this treatment doesn’t work, to be clear. Nor am I saying that the assessment doesn’t work. I’m saying that it looks questionable and you should be careful relying on it in a significant way. I certainly will be from now on.

Paper Gotcha.

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Feel flat after all that? Yea, me too. I basically just told you the thing you do every day doesn’t work. So I’ll try to make things a bit better with some info that is helpful, as a bonus. Here’s something from way back in 2020 (remember those days? sigh). Check it out.

Just Push Anywhere - Generic Vertebral Manips are Equal to Directed Manips in Chronic LBP

The Gist - This study from the Journal of Physiotherapy assessed two different styles of vertebral manips, directed and generic. Building on previous research that showed that generic manips were equal to directed ones in one treatment, the researchers checked out how a long term treatment program with only generic manips would work. What’s a direct vs generic manipulation? A PT applied light, P-A vertebral pressure at each spinal level, and the patient told them where it was most symptomatic. In the direct manipulation group, that level was then selected for manipulation. In the generic manip group, they went through the same pain ID process, then had manips done in the mid-thoracic (T5 or T6). Patients had a total of ten treatments over the course of four weeks, then were assessed at weeks 4, 12, and 26.

Pain intensity was the primary outcome measure, and they also used a disability scale. Total, there were 148 patients in the study and the pain differences at weeks 4, 12, and 26 were all within 0.1 points, not clinically significant. Almost exactly the same! So, manips at the most painful level or mid-thoracic caused the same pain reduction and disability differences weren’t significant either.

Tell Me More - The big question you’re probably asking is “why does this matter?” The study authors assess that as well. Since there are no clinically important differences in pain, disability (according to the Roland Morris Disability Questionnaire) or Global Perceived Effect between the two techniques, it allows a PT to choose where to manip without sacrificing treatment efficacy. According to the study authors:

Based on the results of this trial, the therapist may choose his/her preferred therapy: non-specific or specific manipulation. In the case of patients with severe low back pain, for example, the therapist’s decision would be to manipulate a site away from the painful segment. Also, the therapist’s ability with either technique may be considered. Therapists may choose to manipulate the patient specifically at the most affected level or not, according to the technique in which he/she is most skilled and has the most experience.

They go a bit deeper on this analysis in the whole paper as well, so check that out if you’re looking for more reasons why it matters.

The big remaining questions are: 1) Why these techniques are the same? and 2) What are the weaknesses? The big answers are: 1) We don’t really know but we think that it’s because the lumbar and thoracic regions are interdependent, so this is like treating the thoracic spine to help with neck pain(which works, jsyk) and 2) the therapist wasn’t blinded to the technique used (because, how?). Overall, a really interesting study that opens up new avenues in treating complex patients.

Alright, where’s that paper? Right here!

And on that happier note, that’s our week! Hope the end was helpful. If you want more and to help the Crab, subscribe here, as always:

I don’t have much more to say, so imma jump. Have a good day!