Talk:Subjective Assessment of the Lumbar Spine
The Art and Science of Physical Therapy
Henschke's rule to diagnose spinal fracture in a low risk setting provides physical therapists a unique opportunity to use their clinical intution.
Clinical Decision Rules are usually intended to provide probabilities confirming a diagnosis or predicting an outcome so the physical therapist can make clinical decsions with confidence.
Henschke's rule screens patients for vertebral fractures without the use of expensive and overly sensitive imaging devices.
This rule may be employed in two different settings: low risk and high risk settings. The setting determines the pre-test probability, or prevalence.
The base rate of vertebral fractures in a population of 1,172 patients accessing primary care for treatment of lower back pain in Sydney, Australia was 0.5%. Primary care in Australia is defined as offices of physicians, physical therapists and chiropractors. The base rate of vertebral fractures in patients accessing the emergency room and specialty physicians’ offices for treatment of lower back pain in Sydney, Australia was 3.0%. The predictive power of the decision rule varies with the setting the clinician sees the patient – high risk patients seen in specialty clinics had a higher prevalence of spinal fracture.
The physical therapist's intuition is especially important in the LOW RISK situation when three or more of the subjective variables were present.
- 1 variable present: fracture is 1% likely
- 2 variables present: fracture is 7% likely
- > 3 variables present: fracture is 52% likely
In this situation, the clinical decision rule returns a probability of 52% favoring the diagnosis of vertebral fracture. The rule, in this situation, barely performs better than chance, A physical therapist flipping a coin could do just as well in predicting a spinal fracture (~50%).
Intuiton might include additional items from the patient history, subjective pain complaints, physical exams, special tests and pathology screening exams. Also, a medication list, cognitive status and input from family members could add useful data points that might increase or decrease the probability of a fracture.
This example is meant to demonstrate WHY physical therapist intuition is still important, combined with first-pass screening algorithms that supplement human memory for low-frequency events. In these situations, the use of clinical intuition and experience supplements the algorithmic decision rule.
Henschke's rule to diagnose spinal fracture is a useful algorithm for screening high risk patients. In the low risk setting, such as an ambulatory PT clinic, the rule requires that the physical therapist remain alert to subtle cues that might affect the diagnosis.
Henschke's rule demonstrates clearly how the art and the science of physical therapy are both important in making your diagnosis.
(Note: these values were calculated using a clinical calculator at http://faculty.vassar.edu/lowry/clin1.html)
