Although most back pain is organic, some patients present with complaints of low back pain that are manifestations of a psychosomatic disorder. Other patients may be malingering for secondary gain. To distinguish behavioral (nonorganic) from organic back pain, Waddell and colleagues found eight signs that identify nonorganic back pain. Patients satisfying three or more of these signs may have a behavioral cause for their low back pain.
- Superficial tenderness—discomfort on light touching of the skin overlying the back.
- Nonanatomic tenderness—tenderness that crosses multiple somatic boundaries or moves to various sites during the exam.
- Axial loading—report of low back pain when pressing down on the top of the head of a standing patient.
- Simulated rotation—when the shoulders and pelvis are rotated in unison less than 30 degrees (i.e., acetabular rotation test) in either direction, the structures in the back are not stressed. If the patient reports pain with this maneuver, this test is considered positive.
- Distracted straight-leg raise—report of pain in low back or posterior thigh with less than 10 degrees of elevation of leg when supine, or pain with standard straight-leg raise test when a patient is recumbent but no pain when the patient is sitting and the knee is extended so that the leg is at a 90-degree angle with the pelvis.
- Regional sensory change—“stocking” or global distribution of numbness, not in dermatomal distribution.
- Regional weakness—“breakaway” weakness in a patient with normal strength on muscle testing.
- Overreaction—disproportionate grimacing, tremor, exaggerated verbalization, or collapse in a way not to hurt themselves during the exam.
Other tests suggesting a behavioral or nonorganic cause for back pain:
- Sit-up—a patient with significant back pain cannot do a sit-up. Patients with organic back pain will roll over to their side and push up to a sitting position. If a patient can do a sit-up, his pain is not severe.
- Shoes and socks sign—patients with significant organic back pain should have problems putting on shoes and socks. If these actions are no problem, back pain usually is not severe.
- Mankopf’s test—pain should raise pulse rate 5% or more. Absence of this sign is a positive behavioral sign (unless on beta blockers).
- O’Donoghue’s maneuver—patients with true back pain should have greater passive range of motion than active range. If this is not the case, consider a behavioral cause of pain.