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The Vagaries of the Clinical Exam - Who Can You Trust?
April 29, 2010 by Dr Matthew D. Long
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The Vagaries of the Clinical Exam - Who Can You Trust?
April 29, 2010 by Dr Matthew D. Long
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The Vagaries of the Clinical Exam - Who Can You Trust?
April 29, 2010 by Dr Matthew D. Long
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It is unfortunate that the art of clinical diagnosis is exactly that - an art.
While we are fortunate to have the tools of science available to help us, the ultimate assembly of clinical data to construct a diagnosis is as much an art form as it is a science. However, the clinical decisions that we make on a daily basis must be based upon something concrete or we would be paralysed by indecision. So in the end our experience is often called upon to help us decide which of our examination procedures are really trustworthy. The trouble is, sometimes our most cherished practices may not be as reliable as we'd like.
Take, for example, the humble palpatory examination...
A recent study by Siegenthaler et al (1) suggests that we shouldn't rely upon local facet joint tenderness in the cervical spine as an indicator of the source of pain.
Clearly a core component of the spinal examination is segmental palpation. Whether we are feeling for stiffness, muscular hypertonicity or tenderness, most clinicians use palpation in some fashion to localise a level of 'lesion' and direct their treatment. The problem is, it appears that tenderness might be nothing more than a red herring.
In the study by Siegenthaler et al a palpatory exam was compared to the current 'gold standard' in diagnosing the source of zygapophysial joint pain - the medial branch block (to anaesthetise the joint). It was found that there was no significant correlation between the tender-to-touch facets and the joints that ultimately proved to be the pain source when successfully anaesthetised. Indeed, the point of maximum tenderness and the actual source of pain could be many segments distant.
To quote the authors, "we found that tissue pathology causing pain is not necessarily associated with tenderness to pressure localized at the affected site. Rather, widespread tenderness can be present, irrespective of the site of tissue pathology." They further theorised that these irrelevant sites of tenderness are due to secondary hyperalgesia.
They concluded that, "The finding of this study has 2 main implications. First, it shows that assessment of mechanical pain sensitivity is not diagnostic for cervical zygapophysial joint pain. Palpating the joints or even using more sophisticated methods to assess mechanical pain sensitivity will not provide useful information on the source of pain...
Second, the result challenges the widely accepted assumption that localized tissue damage is accompanied by tenderness to pressure that is limited to or particularly accentuated at the damaged tissue. This assumption is the basis for examining tenderness to pressure in the context of clinical examination of pain patients. The results show that lack of localized tenderness does not exclude localized tissue damage at the tested anatomical structure."
So, if we can't trust tenderness as a reliable indicator of something wrong underneath, what can we trust?
Well that will be the subject of another blog entry...
Matthew D. Long
BSc (Syd) M.Chiro (Macq)
While we are fortunate to have the tools of science available to help us, the ultimate assembly of clinical data to construct a diagnosis is as much an art form as it is a science. However, the clinical decisions that we make on a daily basis must be based upon something concrete or we would be paralysed by indecision. So in the end our experience is often called upon to help us decide which of our examination procedures are really trustworthy. The trouble is, sometimes our most cherished practices may not be as reliable as we'd like.
Take, for example, the humble palpatory examination...
A recent study by Siegenthaler et al (1) suggests that we shouldn't rely upon local facet joint tenderness in the cervical spine as an indicator of the source of pain.
Clearly a core component of the spinal examination is segmental palpation. Whether we are feeling for stiffness, muscular hypertonicity or tenderness, most clinicians use palpation in some fashion to localise a level of 'lesion' and direct their treatment. The problem is, it appears that tenderness might be nothing more than a red herring.
In the study by Siegenthaler et al a palpatory exam was compared to the current 'gold standard' in diagnosing the source of zygapophysial joint pain - the medial branch block (to anaesthetise the joint). It was found that there was no significant correlation between the tender-to-touch facets and the joints that ultimately proved to be the pain source when successfully anaesthetised. Indeed, the point of maximum tenderness and the actual source of pain could be many segments distant.
To quote the authors, "we found that tissue pathology causing pain is not necessarily associated with tenderness to pressure localized at the affected site. Rather, widespread tenderness can be present, irrespective of the site of tissue pathology." They further theorised that these irrelevant sites of tenderness are due to secondary hyperalgesia.
They concluded that, "The finding of this study has 2 main implications. First, it shows that assessment of mechanical pain sensitivity is not diagnostic for cervical zygapophysial joint pain. Palpating the joints or even using more sophisticated methods to assess mechanical pain sensitivity will not provide useful information on the source of pain...
Second, the result challenges the widely accepted assumption that localized tissue damage is accompanied by tenderness to pressure that is limited to or particularly accentuated at the damaged tissue. This assumption is the basis for examining tenderness to pressure in the context of clinical examination of pain patients. The results show that lack of localized tenderness does not exclude localized tissue damage at the tested anatomical structure."
So, if we can't trust tenderness as a reliable indicator of something wrong underneath, what can we trust?
Well that will be the subject of another blog entry...
Matthew D. Long
BSc (Syd) M.Chiro (Macq)
References:
1. Siegenthaler A, Eichenberger U, Schmidlin K, Dent MD, Arendt-Nielsen L, Curatolo M. What Does Local Tenderness Say About the Origin of Pain? An Investigation of Cervical Zygapophysial Joint Pain. Anaesthesia Analgesia. 2010;110:923-7
1. Siegenthaler A, Eichenberger U, Schmidlin K, Dent MD, Arendt-Nielsen L, Curatolo M. What Does Local Tenderness Say About the Origin of Pain? An Investigation of Cervical Zygapophysial Joint Pain. Anaesthesia Analgesia. 2010;110:923-7