Sensory findings after stimulation of the thoracolumbar fascia with hypertonic saline suggest its contribution to low back pain.
Injection of hypertonic saline into deep tissues of the back (subcutis, muscle, or the surrounding fascia) can induce acute low back pain (LBP). So far, no study has analyzed differences in temporal, qualitative, and spatial pain characteristics originating from these tissues. The current study aimed to investigate the role of the thoracolumbar fascia as a potential source of LBP. In separate sessions, 12 healthy subjects received ultrasound-guided bolus injections of isotonic saline (0.9%) or hypertonic saline (5.8%) into the erector spinae muscle, the thoracolumbar fascia (posterior layer), and the overlying subcutis. Subjects were asked to rate pain intensity, duration, quality, and spatial extent. Pressure pain thresholds were determined pre and post injection. Injections of hypertonic saline into the fascia resulted in significantly larger area under the curve of pain intensity over time than injections into subcutis (P<0.01) or muscle (P<0.001), primarily based on longer pain durations and, to a lesser extent, on higher peak pain ratings. Pressure hyperalgesia was only induced by injection of hypertonic saline into muscle, but not fascia or subcutis. Pain radiation and pain affect evoked by fascia injection exceeded those of the muscle (P<0.01) and the subcutis significantly (P<0.05). Pain descriptors after fascia injection (burning, throbbing, and stinging) suggested innervation by both A- and C-fiber nociceptors. These findings show that the thoracolumbar fascia is the deep tissue of the back that is most sensitive to chemical stimulation, making it a prime candidate to contribute to nonspecific LBP but not to localized pressure hyperalgesia.
Chair of Neurophysiology, Centre for Biomedicine and Medical Technology (CBTM), Medical Faculty Mannheim, Heidelberg University, Germany Department of Anesthesiology and Intensive Care Medicine, Medical Faculty Mannheim, Heidelberg University, Germany Mundipharma Research GmbH & Co. KG, Höhenstraβe 10, Limburg (Lahn), Germany.
Andreas
A
Schilder
Ulrich
U
Hoheisel
Walter
W
Magerl
Justus
J
Benrath
Thomas
T
Klein
Rolf-Detlef
RD
Treede
D000328:Adult; D005205:Fascia / Q000000981:diagnostic imaging / Q000187:drug effects*; D005260:Female; D006801:Humans; D007273:Injections, Intramuscular; D017116:Low Back Pain / Q000139:chemically induced* / Q000000981:diagnostic imaging*; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging; D008297:Male; D009619:Nociceptors / Q000187:drug effects / Q000502:physiology; D010147:Pain Measurement / Q000187:drug effects / Q000379:methods*; D012462:Saline Solution, Hypertonic / Q000008:administration & dosage / Q000633:toxicity*; D013268:Stimulation, Chemical; D013904:Thoracic Vertebrae / Q000000981:diagnostic imaging; D014463:Ultrasonography; D055815:Young Adult
D012462:Saline Solution, Hypertonic
Erector spinae muscle; Hypertonic saline; Low back pain; Peripheral sensitization; Thoracolumbar fascia