The authors aim in this study was to examine the difference in the presence of trigger points (TrPs) between patients with chronic nonspecific low back pain (LBP) and healthy people, and to determine the relationship of TrPs with the intensity of ongoing pain, disability, and sleep quality. They conducted a cross-sectional study of 42 patients with nonspecific LBP (50% women), aged 23-55 years old, and 42 age- and sex-matched controls. They explored TrPs bilaterally within the quadratus lumborum, iliocostalis lumborum, psoas, piriformis, gluteus minimus, and gluteus medius muscles in a blinded design. TrPs were considered active if the subject recognized the local and referred pain as familiar symptoms, and TrPs were considered latent if the pain was not recognized as a familiar symptom. Pain measures were collected with a numerical pain rate scale, disability was assessed with the Roland-Morris questionnaire, and sleep quality was determined with the Pittsburgh Sleep Quality Index. Patients with nonspecific LBP showed a greater disability and worse sleep quality than healthy controls (P < 0.001). Patients with nonspecific LBP exhibited a mean of 3.5 ± 2.3 active TrPs. Further, patients with nonspecific LBP showed a greater (P < 0.001) number of latent TrPs (mean: 2.0 ± 1.5) than healthy controls (mean: 1.0 ± 1.5). Active TrPs in the quadratus lumborum, iliocostalis lumborum, and gluteus medius muscles were the most prevalent in patients with nonspecific LBP. More active TrPs was associated with higher pain intensity (rs = 0.602; P < 0.001) and worse sleep quality (rs = 0.338; P = 0.03).
The authors concluded that the local and referred pain elicited by active TrPs in the back and hip muscles contributes to pain symptoms in nonspecific LBP. Individuals with nonspecific LBP had higher disability and worse sleep quality than controls. The number of active TrPs was associated with pain intensity and sleep quality. They added that it is possible that a complex interaction among these factors is present in individuals suffering from nonspecific LBP.