The Great Gordon:
I don’t mean Gordon Ramsay. I do mean Gordon Waddell, a Scottish Orthopedic Surgeon and developer of “Waddell’s Signs”. The “Signs” provide a simple and rapid screen to help identify subjects who may require more detailed evaluation. Waddell simply wanted to be able to determine which patients would have expected outcomes from lumbar surgery vs. those whom would not. The “Signs” now are important components of such profiles for surgeons all over the world.
“Sign, Sign, Everywhere a Sign…”:
And, everybody knows, but misunderstands them. They are not tests for malingering. They are a screen for an unexpected response to testing, altered participation in activity, and anxiety. Waddell standardized the “Signs” on 350 North American and British patients in 1979, and his first article was published in 1980. He has written dozens of articles and one of my favorite textbooks, “The Back Pain Revolution”. The “Signs” consist of a quick clinical screen with 5 categories of tests:
Tenderness related to physical disease is usually localized to a particular skeletal or neuromuscular structure. Reports of tenderness in the following tests suggest an unexpected response. Unexpected responses to palpation may be:
- Superficial or tender to light pinch over a wide area of lumbar skin is unexpected (tenderness in a localized band in a posterior primary ramus distribution is expected in some cases).
- Non-anatomic deep tenderness over a wide area, not localized to one structure, and extending to the thoracic spine, sacrum, or pelvis is unexpected.
These tests give the subject the impression that a particular examination is being carried out when in fact it is not. A movement is simulated w/o being performed. If pain is reported during these simulations, then an unexpected response is suggested. Simulation tests are:
- Axial Loading is performed by standing behind the subject and with both hands placing 2lbs of vertical downward pressure on the head (equivalent to the pressure caused by putting on a baseball cap). Report of low back pain suggests an unexpected response to testing (neck pain is not a positive finding).
- Simulated Rotation is performed by passively rotating the standing subject’s shoulders and pelvis as a unit in the same plane with the feet together. Reports of back pain suggest an unexpected response to testing (leg pain may be expected).
This test assesses the same movement in 2 separate ways: one formally at which time a subject may complain of pain; the other when the subject is aware of a different test being performed at which time they do not complain of pain.
The suggested test – The Straight Leg Raise:
- First the subject is seated on the side of an examination table and told to extend the knee for a manual muscle test of the quadriceps. The hip flexion angle is measured with a goniometer and the MMT performed. Later in the exam the straight leg raise is assessed in supine and again the hip flexion angle is measured. A difference of >/= 40 degrees suggests an unexpected response.
These are widespread displays of dysfunction such as the entire leg, or the entire region below the knee with the essential feature being divergence from accepted neuroanatomy – disturbances should follow a pattern.
Regional Disturbances are either in “Weakness” or “Sensory” reports:
- Regional Weakness Disturbances is when the subject displays partial cog-wheel “give-way” of several muscle groups (quadriceps, hamstrings, dorsiflexors or plantarflexors) in the lower extremity (or both) upon manual muscle testing. Other than cog-wheeling, some subjects display collapsing weakness at which time the leg rapidly descends or falls with the lightest of pressure. A gradual, smooth give-way is the expected response.
- Regional Sensory Disturbances includes complaints of stocking distribution numbness or tingling. Care must be taken not to confuse this with residual multi-level disc pathology.
This may take the form of moaning, collapsing, tremor, sweating, muscle tension, crying, pallor, dizziness, or nausea at a disproportionate level to be suggestive of an unexpected response. It is vital that the evaluator does not introduce his/her own bias into interpretation of the subject’s behavior. It will be obvious.
For Waddell Signs to be considered clinically significant, positive findings must be observed in at least three categories (at least one item in categories with 2 sub-items). Isolated positive findings in two or less categories is not clinically significant – the patient passed.
Understanding the “Signs”:
Most of the co-validation studies involving the “Signs” highlight their significance in identifying those patients with test anxiety, and in predicting treatment and return to work outcomes. The overwhelming majority of studies critical of the “Signs” highlight their misuse as “malingering tests”. So, if you are going to use them, use them correctly.
The bottom line with Waddell Signs is that they should be used as a part of a wider battery of tests to identify whether a patients pain response can or cannot be used to make functional decisions. A full battery of tests including the “Signs” can support other test data which show the patient demonstrating a reliable level of pain reports or an unreliable level of pain associated with their functional ability. A physician armed with this information can then choose the correct clinical pathway for the patient.