I can remember the first time that I saw an inverted reflex: I was examining a lady with severe pain in her left scapula area and pins and needles in the left arm. Her neck was moderately tender to my palpation, but less tender than I was expecting, given the severity of her left shoulder and arm symptoms. I tested her arm strength: weak left triceps and wrist flexors, and poor grip strength. The left biceps reflex seemed normal, as did her brachio-radialis reflex. When i did her left triceps reflex, the response was a bit weird, but I thought that I’d just done the reflex test wrongly…. and Iwent on to test her right arm which all seemed normal. I didn’t bother testing her leg reflexes, because, after all, she had no back pain or leg symptoms, that she had mentioned to me, anyway, so I thought there was no need.
It was only after she had left, that some weird internal memory of the interaction made me think back about my reflex testing of her: when I had tested her left triceps reflex, the biceps muscle had contracted reflexively, not her triceps. This is called an ‘inverted reflex’, and it is indicative of cervical myelopathy. I hadn’t tested it wrongly. I had just interpreted the unusual response as being a failing on my part.
Inversion of the supinator reflex is also indicative of cervical myelopathy (1), and there is a good YouTube example here, which also shows a Hoffman sign, another indicator of cord compression. Hoffmans sign is performed by flicking the distal phalanx of the middle finger downwards looking for flexion of the thumb and index finger. The Tromner test is similar, but is done by flicking the distal digit upwards, looking for the same response.
The most sensitive indicators of cervical myelopathy are:
Tromner's sign
Hyperreflexia
The most specific tests for cervical myelopathy are:
Babinski
Tromner's sign
Clonus
Inverted supinator response
Remember:
Sensitivity is the ability to detect a condition
Specificity is the ability to rule out a condition
(Ideally a test would be both sensitive and specific)
The reference paper for these statements (1) is a meta-analysis, and is a review of 61 articles about cervical myelopathy, so I think the above statements are of significance.
Why are we interested in cervical myelopathy? Because we treat patient’s cervical spines, and patients with cervical myelopathy may sometimes be made worse by manipulative treatment of the cervical spine (2) (3) (4). It is important, therefore, to be able to identify these patients before embarking on a course of manipulative treatment of the cervical spine. Patients with these findings should be referred for MRI scans of the cervical spine to assess the degree of possible spinal cord compression.
What should I have done differently when I was examining my patient?
I should not have assumed that the inverted reflex was just me ‘doing the reflex test wrongly’.
My neurological examination should have included all of the tests of the lower limbs: tendon reflexes, clonus tests and Babinski’s test. This should have been done even though the patient was not complaining about any leg symptoms.
It’s a journey: Kaizen is the practice of continual improvement
I have been a chiropractor for 38yrs. I now mentor practitioners to help them become the clinicians that they want to be.
References