Lower back pain and neck pain: is it possible to identify the painful side by palpation only?

Back pain is often attributed to increased tension in the back muscles, regardless of whether the tension is primary or related to a disc/facet pathology. We hypothesized that when either lower back pain or neck pain is unilateral, the muscle tension would be more pronounced on the painful side and could be detected by palpation alone (i.e., without the need to apply pain-triggering manoeuvres).

Patients with unilateral neck or lower back pain were enrolled in the study. Participants with scoliosis, obesity, a history of spinal surgery or pain radiating below the knee or the elbow were excluded. The patients were examined by comparative muscle palpation only. The examiner was unaware of which body side was painful and the patient was told to remain still and silent. The spinal muscles were examined bilaterally, with superficial and deep palpation. The examiner had to determine on which side the tension was greater. The patients' age, body mass index, time since onset of symptoms and Rolland Morris (lower back pain) and INDIC (neck pain) functional disability questionnaire scores were recorded.

Ninety-one patients with unilateral lower back pain (35 males, 56 females; mean±SD age: 45.2±15 yrs) and 94 patients with unilateral neck pain (26 males, 68 females, 49.1±15 yrs) were enrolled in the study. The lower back pain and neck pain were right-sided in 50 (54.9%) and 53 (56.4%) of cases, respectively. The examiners correctly identified the painful side in 64.8% of the cases of lower back pain (a significantly better percentage than chance alone (i.e. 50%), P=0.02) and 58.5% (P=0.10) of the cases of neck pain. In lower back pain patients, the results were better for right-side pain than for left-side pain (70.0% and 58.5% of correct answers, respectively, ns). In neck pain patients, the results were better for left-side pain than right-side pain (61% and 56.6%, respectively, ns). There were no significant differences between the two examiners' respective performance levels. The patients' clinical parameters did not appear to influence successful detection of the painful side.

Our findings suggest that palpation can detect increased muscle tension in a limited proportion of cases.