Pivot and Leverage Points are some of the concepts for clinical cases that are widespread and implicitly well understood, but not necessarily explicitly described well or discussed. Giving them names in the PSU DPT program has allowed us to explicitly use the concepts in case discussions. Being able to share ideas with a language that is useful is such an important component in education and practice.
You don’t need to start a case knowing pivot or leverage points. But most cases have them and it is a bit useful if you can identify them when they play an important role in decision-making.
Usually we distinguish different causes of symptoms by examining signs (including the results of clinical tests and special tests), where the results of these tests essentially “pivot” you from cause to another. It is sometimes helpful to think about cases as having different underlying physiological, anatomical, mechanical situations that warrant different intervention approaches with the reasons to believe one of these cases may benefit greatly from a particular “leveraging” approach.
A pivot point is a piece (or set) of information (examination findings, etc.) that changes the direction of the examination. Yes, having a positive test and several indications of a DVT would change the direction of an examination of LE pain. It is based on “abduction” – that is making an inference to the most probable cause based on the observed effects. It is essentially what we do when we attempt to identify the cause of a problem so we can reason about how to intervene.
Pivot points involve a test (or set of tests) that pivot us by providing evidence that rules out one cause (lower (-) likelihood ratios which are associated with higher sensitivities) and rules in another cause (higher (+) likelihood ratios that are associated with higher specificities).
In the figure below, Test 1 is positive with Cause 1 and negative otherwise; Test 2 is positive with Cause 2 and negative otherwise; Test 3 is positive with Cause 3 and negative otherwise. So the results of these 3 tests pivot us between these three possible causes. Of course, the causes are not mutually exclusive so it is a bit more complicated than my model here.
A leverage point is a point that if changed we believe will greatly change the status of the system moving forward (movement system, functional system, etc). When an intervention works on a leverage point, just like a lever, there is a greater output than expected based on the input.
There at least two ways that something can be a leverage point.
- Something wrong with the point and it is easily fixed
- The point is a “hub” node, or has an impact on several parts of the system
In the below figure any node leading toward functional movement could be a leverage based on the first way. For example, if joint arthrokinematic movement is impaired and it can be easily fixed it may have a large leveraging effect.
Whereas it takes a node such as Nerve Root Integrity to be a leverage of type 2. As is clear, nerve root integrity impacts several other variables. So, if it is impaired and can be fixed the results are significant since they are leveraged through the system.